B. All crossings with existing utilities with less than 6 feet separation shall be potholed or accurately located by other means.
C. When the depth of the existing utility is unknown, the utility must be potholed.
D. At the pre-construction meeting, or one week prior to starting the work, the Contractor shall provide the following:
1. Specify tracking system used and its capability for both the forward drilling and the backream.
Design Criteria
City of Santa Clara Public Works Department
~ 27 ~
2. A written verification of experience and qualifications of the tracker.
Experience shall include a minimum of 5 previous jobs and/or 1,000 feet of tracking experience with references.
3. Specify HDD equipment used and its capability.
4. Names of the HDD operator and the responsible tracker.
5. Proposed methods to control, collect, transport, and dispose of drilling fluids and spoils.
6. Emergency procedures for inadvertently boring into a live electric conduit, natural gas line, water line, sanitary sewer line, storm drain line, fiber optic cables, or any other utility in the ground (private or public).
Procedures must comply with all applicable regulations.
E. Geotechnical Engineer shall review the Contractor’s submittal and comment on suitability of the proposed equipment with respect to the subsurface conditions described in the geotechnical report and provide a letter of compliance to the City.
F. Contractor shall provide for the tracking and plotting of the HDD operations at all times.
1. Tracker shall check for electrical interference along drill path prior to construction operations for necessary adjustments to a pre-drill plan.
2. Tracker shall provide continuous monitoring and plotting of pilot bore to establish a general running line and pull back operations to establish final location of the installed line.
9.5 As-built Drawings
A. Contractor shall provide the City with As-Built Drawings, meeting the following minimum criteria:
1. As-Built Drawings shall show the layout and profile at a minimum horizontal scale of 1”=40’ and vertical scale of 1"=10'.
2. As-Built Drawings shall be based upon the plot information provided by the tracker.
3. As-Built Drawings must show new construction, clearances and existing improvements (sidewalk, curb, gutter, roadway, utilities, etc.).
Design Criteria
City of Santa Clara Public Works Department
~ 28 ~
9.6 References
A. Bueno, Sharon M. (1999), “Directional Crossing Contractor Association (DCCA) Roundtable – What Do Industry Leaders Have to Say About Safety, Contracts and Rollups?” Directional Drilling Magazine, Dec., p. 18.
B. California Department of Transportation, “HDD Operator Certification Project (January 18, 2000)”.
C. California Department of Transportation, “Guidelines and Specifications for Horizontal Directional Drilling Installations 2000”, pp. 12-22.” D. Twohing, M.A., “The Directional Crossing Contractor Association (DCCA) Directional Crossing Survey Standards 1998”, p. 5.
E. U.S. Army Corps of Engineers, “Guidelines for Trenchless Technology: Curedin-Place (CIPP), Fold-and-Formed Pipe (FFP), Mini-Horizontal Directional Drilling (Mini-HDD), and Microtunneling”, Construction Productivity Advancement Research (CPAR) Program (Final Report, September 1995).
F. DCM/Joyal Engineering, Review Comments – City of Santa Clara Draft Minimum S.O.P. Requirements for H.D.D. Installation, Marc Gelinas/David Mathy, June 27, 2000.
G. Geotechnical Comments, Proposed City of Santa Clara Draft Requirements – HDD-SOP, Hallenbeck & Associates, Adel Kasim, Ph.D., G.E., June 1, 2000.
City of Santa Clara Public Works Department
Design Criteria
~ 29 ~
EXHIBIT A
Typical Legend Symbols
Note: Include only the “proposed” and “existing” legend symbols that are actually used on the plans.
Symbols other than what is shown in this Exhibit may be used subject to approval.
City of Santa Clara Public Works Department
Design Criteria
~ 30 ~
EXHIBIT B
Typical Abbreviations
Note: Show only those abbreviations that are actually used on the plans.
A
AB aggregate base
ABBC asbestos bonded bituminous coated
Abn abandon
Abut abutment
AC asphalt concrete
ACB asphalt concrete base
ACP asbestos cement pipe
ADL added dead load
Adj adjust
Alt alternate
Approx approximate
AS aggregate subbase
Ave avenue
Avg average
@ at
B
BC begin horizontal curve
BCR begin curve return
Beg begin
Bit Ctd bituminous coated
Bk back
Bkf backfill
Bldg building
Blvd boulevard
BM bench mark
Bot bottom
Br bridge
Brg bearing
BTU british thermal unit
BVC begin vertical curve
C
CAP corrugated aluminum pipe
C-C center to center
CG center of gravity
Chnl channel
CI cast iron
CIP cast iron pipe
CIPCP cast in place concrete pipe
CL chain link
Cl class
Clr clear, clearance
CM corrugated metal
CMP corrugated metal pipe
Co county
Col column
Conc concrete
Cond conduit
Const construct, construction
Cont continuous
Coord coordinate
Cr creek
CSP corrugated steel pipe
CTB cement treated base
CTPB cement treated permeable base
CTPM cement treated permeable material
Ctrs centers
Culv culvert
CL centerline
D
D depth
Dbl double
Deg degree
Det detail, detour
DI drainage inlet, drop inlet
Dia diameter
Diaph diaphragm
Dist distance, district
Dr drive
Dwy driveway
E
E east
Ease easement
EB eastbound
EC end horizontal curve
ECR end curb return
Elec electrolier
Elect electric
Elev elevation
Emb embankment
Engr engineer
EP edge of pavement
EVC end vertical curve
Exc excavation
Exist, (E) existing
Exp expansion, expressway
Exp Jt expansion joint
Ext exterior
City of Santa Clara Public Works Department
Design Criteria
~ 31 ~
F
F & C frame and cover
F & G frame and grate
Fdn foundation
FG finished grade
FH fire hydrant
Fig figure
FL flow line
FS finished surface
Ftg footing
Fwy freeway
G
g acceleration due to gravity
Ga gage
Galv galvanized
GR guard railing
GSP galvanized steel pipe
Gtr gutter
H
H height
h, hr hour
hdwl headwall
HMA hot mixed asphalt
Horiz horizontal
HP high point, horsepower
HW headwall
Hwy highway
I
IB imported borrow
ID inside diameter
Int interior
Inv invert
Irr irrigation
J
Jct junction
JP joint pole
JS junction structure
Jt joint
K
L
L length
Ln lane
Loc location
LS lump sum
Lt left
M
Maint maintenance
Max maximum
Med median
MH manhole
Min minimum
Misc miscellaneous
Mod modified, modify
Mon monument
Mtl material
N
N north
NB northbound
No. number (must have period)
Nos. numbers (must have period)
NTS not to scale
O
OC overcrossing
OD outside diameter
OH overhead
Opp opposite
P
P page
PAP perforated aluminum pipe
PB pull box
PC point of curvature
PCC point of compound curve
PCP perforated concrete pipe
PCVC point of compound vertical curve
Ped pedestrian
Ped OC pedestrian overcrossing
Ped UC pedestrian undercrossing
PI point of intersection
PJP partial joint penetration
P/L property line
POC point of horizontal curve
POT point of tangent
POVC point of vertical curve
PP power pole
PPP perforated plastic pipe
PRC point of reverse curve
PRF pavement reinforcing fabric
PRVC point of reverse vertical curve
PS&E plans, specifications and estimates
PSP perforated steel pipe
PT point of tangency
PVC polyvinyl chloride
Pvmt pavement
City of Santa Clara Public Works Department
Design Criteria
~ 32 ~
Q
Qty quantity
R
R radius
RCP reinforced concrete pipe
Rd road
Reinf reinforced
Ret retaining
Rev revised
Rdwy roadway
RP radius point
RR railroad
Rt right
Rte route
RW redwood
R/W right of way
S
S south
SB southbound
SD storm drain
Sec second
Sht sheet
Sim similar
Specs specifications
St street
Sta station
Std standard
Str structure
Surf surfacing
SW sidewalk
Swr sewer
Sym symmetrical
T
Tan tangent
TC top of curb
TCB traffic control box
Tel telephone
Temp temporary
TG top of grade
Tot total
TP telephone pole
Trans transition
TS traffic signal
Typ typical
U
UC undercrossing
UD underdrain
UON unless otherwise noted
UP underpass
V
V valve
Var variable
VC vertical curve
VCP vitrified clay pipe
Vert vertical
Vol volume
W
W west
WB westbound
WM wire mesh
WS water surface
WSP welded steel pipe
Wt weight
WV water valve
WW wing wall
X
X sec cross section
Xing crossing
Y
Yr year
Yrs Years
Z
City of Santa Clara Public Works Department
Design Criteria
~ 33 ~
EXHIBIT C
General Notes
1. All materials and workmanship shall conform to the City’s Standard Details, Standard Specifications, and General Requirements.
2. Contractor shall secure an Encroachment Permit from the City Engineering Department and pay appropriate fee prior to commencement of work. All work within the public right-of-way shall be done under a single Encroachment Permit.
3. It is the Contractor’s responsibility to verify the location of all existing utilities with the appropriate utility agencies prior to the commencement of construction. Contractor shall notify all public and private utility owners 48 hours prior to commencement of work adjacent to the utility. Contact Underground Service Alert (USA) at 811 or 800- 227-2600.
4. The Contractor shall notify, by circular, all business establishments and residences located in areas affected by the work at least forty-eight (48) hours prior to start of construction. Circular shall be subject to the approval of the City Engineer.
5. Unless otherwise directed by the City Engineer in the field: at each location where new curb/gutter is to be installed on an existing street (driveway installation, driveway abandonment, curb ramp installation, curb face drainage installation, etc.) pavement reconstruction shall be required. An 18-inch wide band of pavement shall be removed and replaced along the entire length of curb/gutter installation. Removal depth (saw cuts required) shall be to the base material on streets with A.C. or P.C.C. pavement four (4) inches or less in thickness. Removal depth shall be two (2) inches minimum on streets with A.C. (grind) and four (4) inches minimum on streets with P.C.C. (saw cut) pavement thickness greater than four (4) inches. Replace with A.C. or P.C.C. (dowels required) to match existing pavement.
6. All sidewalk, curb, and gutter damaged as a result of the project shall be removed and replaced to the nearest score mark or as directed by the City Engineer. Installation of new sidewalk, curb and gutter against existing improvements shall require a sidewalk contact joint (dowels required).
7. Partial replacement of a driveway is not allowed. A driveway that has been cut or damaged must be replaced in its entirety. The new replacement driveway must meet current City Standards which may affect on-site improvements and/or require a sidewalk easement.
8. Slurry seal shall be required on all new street pavement (e.g., trench work, potholes, and street widenings). Slurry seal shall extend twelve inches beyond the limit of pavement reconstruction.
9. All manholes, valve boxes, monument boxes, and other structures in the pavement area shall be adjusted to finish grade before paving final lift.
10. Grade breaks on curbs on sidewalks are to be rounded off on form work and finished surfacing.
City of Santa Clara Public Works Department
Design Criteria
~ 34 ~
11. The contractor shall be responsible for the preservation and/or perpetuation of existing survey monuments (curb tags, iron pipes, street monuments, etc.) noted on the plans or found during construction per Section 8771of the California Business and Professions Code. If a survey monument has the potential of being disturbed or within 3 feet of the Work, the monument shall be located, referenced, and a corner record shall be filed with the Santa Clara County Surveyor, and a duplicate of the corner record shall be submitted to the City Engineer prior to the start of construction. Should any survey monument be damaged or destroyed during construction, the contractor shall reestablish said monument per City standard, file a corner record with the Santa Clara County Surveyor, and submit a duplicate of the corner record to the City Engineer prior to final project notice of completion issued by the Department of Public Works. The contractor shall, at his/her expense, hire a licensed professional civil engineer authorized to practice land surveying or land surveyor to perform the work.
12. All surplus and unsuitable material shall be removed from public right-of-way.
13. Contractor shall provide adequate dust control and keep mud and debris off the public right-of-way at all times.
14. All trenches and excavations shall be constructed in strict compliance with the applicable sections of California and Federal O.S.H.A. requirements and other applicable safety ordinances. Contractor shall bear full responsibility for trench shoring design and installation.
15. Existing utilities shown are based upon record information and are approximate in location and depth. The Contractor shall pothole all existing utilities that may be affected by new facilities in this contract, verify actual location and depth, and report potential conflicts to the Engineer prior to excavating for new facilities.
16. Contractor shall perform his construction and operation in a manner, which will not allow harmful pollutants to enter the storm drain system. To ensure compliance, the Contractor shall implement the appropriate Best Management Practice (BMP) as outlined in the brochures entitled “Best Management Practice for the Construction Industry” issued by the Santa Clara Valley Nonpoint Source Pollution Control Program, to suit the construction site and job condition.
17. Overnight parking of construction equipment in the public right-of-way shall not be permitted, except at location(s) approved by the City Traffic Engineer.
18. All sanitary sewer and/or storm drain mains to be abandoned shall be filled with sand or control density fill (CDF) and plugged at each end with a 6” thick wall of Class “A” P.C.C.
19. Abandonment of sanitary sewer lateral at the property line shall include the complete removal of the Christy Box, all vertical pipes and the 45º Wye. The remaining lateral ends shall be plugged with 6” thick wall of Class “A” P.C.C., ensuring no concrete enters the main. Abandonment of sanitary sewer lateral at the main will occur when lateral connects at a manhole or as determined by the City. Plug the lateral end with 6” thick wall of Class “A” P.C.C., and fill lateral with sand or control density fill (CDF), making a smooth trowel finish on the inside wall of the manhole for manhole connections.
20. Unless otherwise noted, Class 2 A.B. under curb, gutter, and street sections paved with asphalt concrete shall be compacted to 95% relative compaction (minimum).
21. Near completion of the Project, contractor shall replace damaged curb and gutter along Project frontage as directed by the City Engineer.
City of Santa Clara Public Works Department
Design Criteria
~ 35 ~
EXHIBIT D
Figure 3-3 of Sanitary Sewer Capacity Assessment Report, May 2007 City of Santa Clara Public Works Department
Design Criteria
~ 36 ~
EXHIBIT E
Table 3-2 of Sanitary Sewer Capacity Assessment Report, May 2007 City of Santa Clara Public Works Department
Design Criteria
~ 37 ~
EXHIBIT F
Santa Clara County Drainage Manual 2007
Figure B-2: IDF for M.A.P. of 14 Inches
Drainage Manual 2007
County of Santa Clara, California
City of Santa Clara Public Works Department
Design Criteria
~ 38 ~
EXHIBIT G
Standard Form DM-2: Santa Clara County Drainage Manual 2007 Figure C-1: Calculation Sheet, Storm Drain Design by Rational Method Drainage Manual 2007
County of Santa Clara, California
EXAMPLE
Appendix G
City of Santa Clara Standard Details
Appendix G
i
S:\Engineering\Standard Details\Website\2016\00_3-Std. Dwg.TOC.docRevised:3/7/2016
CITY OF SANTA CLARA
DEPARTMENT OF PUBLIC WORKS
STANDARD DETAILS
TABLE OF CONTENTS
Title Detail Page
STREETS:
Driveway Standards ............................................................................................ST-1 1 Driveway Locations ............................................................................................ST-2 2 Driveway Locations at Curb Returns...................................................................ST-3 3 Residential Driveway with Attached Sidewalk ...................................................ST-4 4 Residential Driveway with Separated Sidewalk..................................................ST-5 5 Depressed Driveway for Existing 5’Attached Sidewalk .....................................ST-6 6 Depressed Commercial Driveway for Existing 5’Attached Sidewalk.................ST-7 7 Commercial Driveway with/without Separated Sidewalk...................................ST-8 8 Commercial Driveway with Attached Sidewalk..................................................ST-9 9 Curb-Return Driveway.........................................................................................ST-10 10 Monolithic Curb and Gutter.................................................................................ST-11 11 Monolithic Curb, Gutter and Sidewalk................................................................ST-12 12 Concrete Median Curbs and Valley Gutter..........................................................ST-13 13 Median Cobblestone Installation .........................................................................ST-13A 13A Curved Curb Ramp ..............................................................................................ST-14 14 Straight Curb Ramp .............................................................................................ST-15 15 Curb Ramp Grooving and Truncated Dome Details............................................ST-16 16 Concrete Joints.....................................................................................................ST-17 17 Dowel Connections..............................................................................................ST-18 18 Sidewalk to Curb Connection ..............................................................................ST-19 19 Monument............................................................................................................ST-20 20 Special Monument Box Adjustment....................................................................ST-21 21 Median Island Taper ............................................................................................ST-22 22 Cul-De-Sac...........................................................................................................ST-23 23 Trench Backfill and Pavement Replacement.......................................................ST-24 24 Soil Boring Backfill and Pavement Replacement................................................ST-25 25 Asphalt Concrete Pavement Thickness Requirements .......................................ST-26 26 Steel Plate Benching ............................................................................................ST-27 27 Street Barricade....................................................................................................ST-28 28 STORM DRAINS:
Curb Face Drainage Outlet ..................................................................................SD-1 29 Curb Inlet Catch Basin.........................................................................................SD-2 30 Type "A" Curb Inlet Catch Basin ........................................................................SD-3 31 Drop Inlet Catch Basin.........................................................................................SD-4 32 ii
S:\Engineering\Standard Details\Website\2016\00_3-Std. Dwg.TOC.docRevised:3/7/2016 TABLE OF CONTENTS (CON’T)
STORM DRAINS (CON’T):
Adaptation for Existing Catch Basin in New Driveway......................................SD-5 33 Catch Basin Hood, Frame and Grate ...................................................................SD-6 34 Concrete Lug........................................................................................................SD-7 35 Connection to Public Storm Drain System..........................................................SD-8 36 SANITARY SEWERS:
4” & 6” Sanitary Sewer Clean-Out......................................................................SS-1 37 4” & 6” Sanitary Sewer Lateral Connection........................................................SS-2 38 4” & 6” Sanitary Sewer Lateral Connection to Existing Main............................SS-3 39 Standard Drop Manhole.......................................................................................SS-4 40 Flushing Inlet .......................................................................................................SS-5 41 Sanitary Sewer Manhole Topper .........................................................................SS-6 42 DRAINAGE STRUCTURES:
Manhole ...............................................................................................................DS-1 43 Type "A" Manhole...............................................................................................DS-2 44 Manhole Frame, Cover and Grate........................................................................DS-3 45 Lateral Connection to Existing Manhole .............................................................DS-4 46 Manhole Raising ..................................................................................................DS-5 47 Concrete Collar....................................................................................................DS-6 48 TRAFFIC:
Street Name Sign and Location ...........................................................................TR-1 49 Traffic Signal Controller Cabinet ........................................................................TR-2 50 Traffic Signal Power Panel ..................................................................................TR-3 51 Type III Pole ........................................................................................................TR-4 52 Traffic Signal Trench Details...............................................................................TR-5 53 Traffic Signal Pull Box ........................................................................................TR-6 54 Traffic Signal Detector Loops Spacing Detail.....................................................TR-7 55 Typical Stop Intersection .....................................................................................TR-8 56 LANDSCAPE:
Palm Tree Planting...............................................................................................LS-1 57 Tree Planting........................................................................................................LS-2 58 Tree Staking.........................................................................................................LS-3 59 Tree Well .............................................................................................................LS-4 60 Shrub Planting......................................................................................................LS-5 61 Tree Protection ....................................................................................................LS-6 62 Landscape Trenching Details...............................................................................LS-7 63 Tree and Shrub Bubbler.......................................................................................LS-8 64 iii
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LANDSCAPE (CON’T):
Pop-Up Sprinkler .................................................................................................LS-9 65 Quick Coupler......................................................................................................LS-10 66 Landscape Filter...................................................................................................LS-11 67 Flow Sensor .........................................................................................................LS-12 68 Union Ball Valve .................................................................................................LS-13 69 Pressure Reducing Valve .....................................................................................LS-14 70 Remote Control Valve .........................................................................................LS-15 71 Low Volume Remote Control Valve ...................................................................LS-16 72 Master Remote Control Valve .............................................................................LS-17 73 Backflow Enclosure .............................................................................................LS-18 74 Reduced Pressure Backflow Assembly ...............................................................LS-19 75 Irrigation Valve Box Locations ...........................................................................LS-20 76 Irrigation Satellite (Radio Communication) ........................................................LS-21 77 Low Voltage Irrigation Wire Connection............................................................LS-22 78 MISCELLANEOUS:
Chain Link Fence ................................................................................................MI-1 79 Chain Link Double Swing Gate ..........................................................................MI-2 80 Concrete Saddle Upper Pipe Installation .............................................................MI-3 81 Concrete Saddle Lower Pipe Installation.............................................................MI-4 82 APPENDIX:
Appendix A - General Notes ...............................................................................AP-A 83 Department of Public Works
City of Santa Clara, CA
STANDARD DETAILS
STREET SECTION
DETAILS ST-1 TO ST-28
Department of Public Works
City of Santa Clara, CA
STANDARD DETAILS
STORM DRAIN SECTION
DETAILS SD-1 TO SD-8
Department of Public Works
City of Santa Clara, CA
STANDARD DETAILS
SANITARY SEWER SECTION
DETAILS SS-1 TO SS-6
Department of Public Works
City of Santa Clara, CA
STANDARD DETAILS
DRAINAGE STRUCTURE SECTION
DETAILS DS-1 TO DS-6
Department of Public Works
City of Santa Clara, CA
STANDARD DETAILS
TRAFFIC SECTION
DETAILS TR-1 TO TR-8
Department of Public Works
City of Santa Clara, CA
STANDARD DETAILS
LANDSCAPE SECTION
DETAILS LS-1 TO LS-22
Department of Public Works
City of Santa Clara, CA
STANDARD DETAILS
MISCELLANEOUS SECTION
DETAILS MI-1 TO MI-4
Appendix H
Emergency Response Procedures
RECEIVING A SERVICE REQUEST - DURING BUSINESS HOURS
START
Gather all necessary information
for response: · Caller’s name
· Address of problem
· Cross Street
· Contact phone number(s)
· Description of problem
· Date & Time
Does the description of the
problem sound like it is a possible
sewer related problem?
Dispatch one sewer division
maintenance worker. Continue to
“Responding to a Service
Request” and create a work order
Does the description of the
problem sound like it is the
responsibility of a different City
Department?
Transfer customer’s information to
the appropriate City department
Inform the customer that the
problem is not the City’s
responsibility. Provide the customer
with any helpful direction (if
appropriate) No paperwork is
necessary
STOP
YES
YES
NO
NO
CITY OF SANTA CLARA SPILL EMERGENCY RESPONSE PLAN Latest version - June 5, 2023 RECEIVING A SERVICE REQUEST – AFTER BUSINESS HOURS, WEEKENDS, AND HOLIDAYS START
Gather all necessary information
for response: · Caller’s name
· Address of problem
· Cross Street
· Contact phone number(s)
· Description of problem
· Date & Time
Does the description of the
problem sound like it is a possible
sewer related problem?
Inform the
customer that the
problem is not the
City’s
responsibility. Provide the
customer with any
helpful direction (if
appropriate). No
paperwork is
necessary
Is a Water or Sewer Division on- call maintenance worker available?
STOP
Is the problem the responsibility
of a different City Department?
Follow after hours
procedures for the
appropriate
department
Contact
designated oncall private
contractor and
transfer customer/
problem
information
Dispatch one oncall maintenance
worker. Continue
to “Responding to
a Service
Request” and
create a work
order
Upon initial investigation of the
service request, does the
contractor identify an spill?
Private contractor
addresses service
request
Private contractor
calls Operators. Operators call
Sewer Division
staff working up
the chain of
command until one
is reached and
dispatched. Continue to
“Responding to a
Service Request”
NO
NO NO
NO
YES
YES
YES
YES
CITY OF SANTA CLARA SPILL EMERGENCY RESPONSE PLAN Latest version - June 5, 2023 SOP TITLE: SPILL RESPONSE
PURPOSE:
1. The goals of the outdoor backup response plan are to:
a. Stop, contain, and recover spills as quickly and thoroughly as possible. b. Protect public health, environment, and property.
c. Restore affected areas as quickly as possible.
2. Every effort must be made to prevent spills from reaching surface water.
PPE REQUIRED:
1. General
a. Gloves
b. Rubber Boots
c. Eye protection
d. Safety vest
2. Operating jet truck/ Vac-Con
a. Hearing protection
b. Face protection
SPECIFIC HAZARDS:
1. Raw Sewage
2. Traffic Control
a. Foot
b. Automotive
SAFETY PRECAUTIONS:
1. Secure the area from the public and control traffic using:
a. Cones
b. Arrow board
c. Warning signs
STANDARD OPERATING PROCEDURE:
OPERATING REQUIREMENTS:
1. Jet Truck
a. Class A or B California Driver’s License
2. Vac-Con
a. Training
b. Class A or B California Driver’s License
CITY OF SANTA CLARA SPILL EMERGENCY RESPONSE PLAN
- Page 1
PRE-CHECK OF EQUIPMENT:
1. Jet Truck
a. Refer to “JET TRUCK” SOP
2. Vac-Con
a. Refer to “VAC-CON” SOP
OPERATING PROCEDURE:
PRELIMINARY:
1. Secure the area from the public and control traffic using:
a. Cones
b. Arrow board
c. Warning signs
2. Estimate the flow volume
a. Refer to “ESTIMATE THE FLOW” SOP and/or
b. Photograph the spill such that the flow rate can be determined later.
3. Troubleshoot the cause/location of the spill
a. Check the Block Book to identify which manholes need to be checked. i. Corner lots & properties with sewer easements might have lines on two or more sides.
ii. If there is more than one sewer main in front of or adjacent to the property, all of those mains should be checked.
4. Call for additional support and equipment as needed.
PROCEDURE:
1. Contain the spill
a. Stop and contain the spill prior to storm drain entry. b. Cover drop inlets (DIs) with plastic sheeting.
c. Sand bag area and gutter.
d. Sand bag downstream storm drain if spill has already entered the storm system.
2. Resolve the problem
a. If the spill is the result of a main line blockage:
i. Refer to “JET TRUCK” and “VAC-CON OPERATION”
SOPs to clear the blockage.
ii.If the blockage cannot be cleared quickly, refer to “SETTING UP A BY-PASS” SOP.
CITY OF SANTA CLARA SPILL EMERGENCY RESPONSE PLAN
SOP TITLE: SPILL RESPONSE - Page 2
iii. After clearing the blockage, check to make sure that all high water subsides. It is possible that the main has plugged again, especially with large chunks of grease and root masses.
b. If the spill is the result of a blockage in the portion of the lateral between the property line cleanout and the main:
i. Refer to the “CUTTERS” SOP to clear the blockage.
ii. After clearing the blockage, flush the lower lateral to ensure that it is clear.
3. Perform final volume estimate
a. Refer to “ESTIMATE THE FLOW” SOP
4. Clean Up
a. Vacuum as much of the spill as possible
b. If the spill is near a clean out: sweep, rake, or wash debris and liquid back into the stand pipe.
c. Wash area as necessary and remove all debris. Refer to “CLEAN UP OF GUTTERS AND MANHOLES” SOP as appropriate.
d. Clean any contaminated storm drains. Contain and reclaim waters generated in the cleaning process.
e. Estimate spill volume reclaimed for reporting purposes. f. Once the cleanup is complete, remove all sand bags and plastic sheeting and dispose of properly.
5. Documentation and notifications
a. Photograph the affected area.
b. Follow the “NOTIFY THE CUSTOMER” procedure.
c. Follow the “COMPELTE THE PAPERWORK” procedure.
d. Follow the “SPILL NOTIFICATION” procedure.
e. Notify the Assistant Superintendent of the backup immediately.
SIGNATURE BLOCK:
CITY OF SANTA CLARA SPILL EMERGENCY RESPONSE PLAN
SOP TITLE: SPILL RESPONSE - Page 3
Latest version - June 5, 2023
City of Santa Clara
Spill Notification and Reporting
Effective: September 9, 2013
Did the spill reach surface water and/or reach a
drainage channel tributary to a surface water, or a Municipal Separate Storm Sewer System (MS4) and not fully captured and returned to the sanitary sewer
system1?
Did the spill equal or
exceed 1,000 gallons?
START
1. Any volume of wastewater not recovered from the MS4 is considered to have reached surface water unless the storm drain system discharges to a dedicated storm water or groundwater infiltration basin) e.g., infiltration pit, percolation pond).
2. Spill information requested may include:
- Name of person notifying Cal OES/direct return phone number - Indication of whether the spill has been contained - Estimated spill volume discharged (gallons) - Indication of whether surface water is impacted - If ongoing, estimated spill discharge rate (gallons per minute - Name of surface water impacted by the spill, if applicable - Spill Incident Description - Indication of whether a drinking water supply is or may be impacted by the spill a. Brief narrative - Any other known spill impacts
b. On-scene point of contact for additional information - Spill incident location (address, city, state, and zip code). c. Date/time enrollee became aware of the spill
d. Name of sanitary sewer system agency causing the spill e. Spill cause (if known)
Did the spill equal or
exceed 1,000 gallons?
Within 2 hours of
becoming aware, call Cal OES at
(800) 852-7550
and obtain a
notification control
number2
Did the spill equal or
exceed 50,000 gallons?
Conduct water
quality sampling
within 48 hours
Was the spill caused by
blockages or other problems
within a privately-owned
lateral
This is a Category 2
Spill, see reporting
requirements on
This is a Private
Lateral Sewage
Discharge, see reporting
requirements on
This is a Category 1
Spill, see reporting
requirements on
This is a Category 3
Spill, see reporting
requirements on
Submit Spill
Technical Report
within 45 days (see reporting
requirements on
YES YES
YES
YES
NO
NO NO
NO NO
YES
City of Santa Clara
Spill Notification and Reporting
Effective: September 9, 2013
Category 1 and
Category 2* Spill
Reporting
Requirements
Certified Reports – submitted to CIWQS
within 15 calendar
days of the end date
of the spill
Draft Reports – submitted to CIWQS
within 3 business
days
Category 3 Spill
Reporting
Requirements
Private Lateral
Sewage Discharge
Reporting
Requirements
Spill Technical Report
Requirements
1. Spill Contact Information: Name &
telephone number of enrollee contact
person who can answer specific questions
about the spill being reported. 2. Spill Location Name
3. Location of the spill event by enterting
GPS coordinates 1 4. Whether or not the spill reached surface water, a drainage channel, or entered and
was discharged from a drainage structure. 5. Whether or not the spill reached a municipal separate storm drain system. 6. Whether or not the total spill volume that reached a MS4 drain system was fully
recovered. 7. Estimate of the spill volume, inclusive of all discharge point(s).
8. Estimate of the spill volume that
reached surface water, a drainage channel, or was not recovered from a storm drain. 9. Estimate of the spill volume recovered (if applicable)
10. Number of spill appearance points
11. Description & location of spill
appearance point(s). If a single sanitary
sewer system failure results in multiple
spill appearance points, each appearance
point must be described
12. Spill start date and time
13. Date and time the enrollee was notified, or self-discovered, the spill
14. Estimated operator arrival time
15. For spills greater than or equal to 1,000
gallons, the date and time Cal OES was
called
16. For spills greater than or equal to 1,000
gallons, the Cal OES control number. *Draft Category 2: Items 1-14 from above.
All information in Category 1 Draft Report, and
in addition: 1. Description of spill destination(s).
2. Spill end date and time. 3. Spill Causes (mainline blockage, roots, etc).
4. Spill failure point (main, lateral, etc).
5. Whether or not the spill was associated with
a storm event. 6. Description of spill corrective action, including steps planned or taken to reduce, eliminate, and prevent reoccurrence of the overflow; and a schedule of major milestones
for those steps. 7. Description of spill response activities
8. Spill response completion date. 9. Whether or not there is an ongoing investigation, the reasons for the investigation
and the expected date of completion. 10. Whether or not a beach closure occurred or may have occurred as a result of the spill.
11. Whether or not health warnings were
posted as a result of the spill.
12. Name of beach(es) closed and/or impacted. If no beach impacted, select NA
13. Name of surface water(s) impacted. 14. If water quality samples were collected, identify parameters the water quality samples were analyzed for. If no samples were taken, select NA
15. If water quality samples were taken, identify
which regulatory agencies received sample
results. If no samples taken, select NA. 16. Description of methodology(ies) and type of data relied upon for estimations of the spill
volume discharged and recovered. 17. Spill Certification: Upon spill certification, the CIWQS Online Spill Database will issue a final spill ID number. *Certified Category 2: Items 1-14 in Draft Report, and Items 1-9, and 17 from above.
Items 1-14 in Draft
Reports, and Items
1-6, and 17 in
Certified Reports
May be
voluntarily
reported to
CIWQS
1. Causes and Circumstances of the spill: a. Complete and detailed explanation of how and when the spill was discovered. b. Diagram showing the spill failure point, appearance point(s), and final destination(s) c. Detailed description of the methodology employed and available data used to calculate
the volume of the spill, and if applicable, the
spill volume recovered. d. Detailed description of the cause(s) of the spill.
e. Copies of original field crew records used to
document the spill.
f. Historical maintenance records for the failure
location
2. Enrollee’s Response to SSO: a. Chronological narrative description of all actions taken by enrollee
b. Explanation of how the SSMP Overflow
Emergency Response plan was implemented
to respond to and mitigate the spill
c. Final corrective action(s) completed and/or planned to be completed, including a schedule for actions not yet completed. 3. Water Quality Monitoring: a. Description of all water quality sampling activities conducted including analytical results
and evaluation of the results. b. Detailed location map illustrating all water quality sampling points.
Submitted within 45
calendar days of the
Spill end date for
spills of 50,000
gallons or greater
Certified Report – submitted to CIWQS
within 30 calendar
days of the end of
month in which the
spill occurred
1 if one spill event results in multiple appearance points in a sewer system asset, the enrollee shall complete one spill report in the CIWQS Online Spill Database which includes the GPS coordinates for the location of the spill appearance point closest to the failure point, blockage or location of the flow condition that caused the spill, and provide descriptions of the locations of all other discharge points associated with the spill event.
SOP Title: Jet Truck
Purpose:
To clean sewer Lines to prevent grease, sediment build-up and root blockages.
To identify areas of excessive Fats, oils and grease discharges and root intrusion.
Specific Hazards:
Traffic Safety, working in and around open manhole, hazardous gases, and possible hazardous materials
Safety Precaution:
1. Traffic Hazards- evaluate traffic and set up safety precautions as needed
2. Gas detection monitor with trained individual
3. Working in manhole requires two people to be present Standard Operating Procedure
1. Operating Requirements
a. Must have a class A or B license
2. Pre-Check Equipment
a. Preform Pre-Trip Inspection and fill out DOT tag
b. Check and test truck safety features:
Arrow board, beacon and strobes
c. Make sure fuel tank and DEF tank is adequate for the job d. Make sure water tank is full – can be filled from both sides of truck suing the fill hose
3. Operating Procedure
Preliminary
1. Park Jet Truck with hose reel positioned over the downstream manhole from stoppage
a. Use back-up camera to help position truck
b. Hose reel extends out and pivots left and right
CAUTION: DO NOT RUN WATER PUMP WITHOUT WATER
(THERE IS A LOW WATER LEVEL WARNING LIGHT)
Procedure:
1. Truck in Neutral and Brake engaged, Engage PTO (Work Mode ON) inside the truck cab or on the rear Dash Controls
2. Place Tiger tail hose guide on jet hose
3. Select proper skid and jet head for the project
4. Lower hose down into the manhole facing upstream with Payout switch
5. Zero footage counter
6. Suction valve switch to Open
7. Water jet switch to High (pressure) or Low (pressure)
8. Throttle increase switch to raise motor RPM and Water pressure
9. Throttle Water Pressure up to suggested pressure for size of main DO NOT pressurize more than 2500 psi
10. Jet upstream with Payout switch and Speed control knob
11. Once hose becomes slack the jet head has hit the blockage, allow for the jet head to work through blockage.
12. After blockage is cleared and the main is draining Decrease Throttle, switch to water jet off and suction valve closed
13. Allow for manholes to drain and check downstream manholes for flow
14.. After manhole(s) have drained, follow steps 5-9 to continue upstream jetting to next manhole
15. With Speed control knob and Retrieval hose switch clean main slowly back to starting manhole
16. Black Leader Hose indicates jet head is 20 feet from manhole
17. Throttle Decrease switch to Lower motor RPM and Water pressure
18. Water jet switch OFF
19. Suction valve switch to Closed
20. Retrieve remaining hose
21. Disengage PTO (Work Mode ON) inside the truck cab or on the rear Dash Controls
SOP TITLE: VAC-CON OPERATION
SSMP/SSO REQUIREMENT: If one thousand (1,000) gallons or more of sewage escapes the collection system or sewage reaches the water ways or storm system and is NOT recovered, the Superintendent or Assistant Superintendent must be notified IMMEDIATELY.
PURPOSE: To clean up, remove and properly dispose of any sewage that may have escaped from the collection system
PPE REQUIRED: Hard hat, gloves, safety vest, ear plugs (as needed), face shield (as needed) SPECIFIC HAZARDS: Traffic safety, possible hazardous materials, working in and near open manhole, overhead lines (moving boom, lifting bed) suction tube SAFETY PRECAUTIONS:
1. Any work to be done in the manhole must have at least 2 people
2. Evaluate traffic so proper safety can be set up
3. Gas detection monitor and trained operator
STANDARD OPERATING PROCEDURE:
OPERATING REQUIREMENTS:
1. Must have A/B license to operate
PRE-CHECK OF EQUIPMENT:
1. Do a pre-trip inspection and fill out DOT tag
2. Do a safety check: cones, arrow board, beacon, strobe
3. Check tank for water level/fill if needed - (fill hose on passenger side behind cab) OPERATING PROCEDURE:
PRELIMINARY:
1. Position VAC-CON so that jet hose and vacuum tube are over downstream manhole\
2. Truck in neutral with brake engaged
A. JETTING PROCEDURE:
1. Turn ON secondary motor
2. Control joystick to hose reel control 1%, 25%, 50%, 75% 100% select what is needed
3. Choose proper head and skid to perform tasks
4. Place Tiger tail hose guide on jet hose
5. Lower jet hose into manhole facing upstream using Control Joystick
6. Engage hose reel (hose reel/lever to ON/pump control to ON)
7. Feed out jet hose in upstream direction
8. Throttle water pressure up to required PSI to jet – joystick right side buttons - GREEN Throttle up, RED Throttle down or toggle switch up or down
9. Zero footage counter
10. Throttle water pressure up to suggested pressure for size of main CAUTION: DO NOT PRESSURIZE MORE THAN 2500 PSI
11. Jet upstream using Control Joystick
12. Once hose becomes slack the jet head has hit the blockage, allow for the jet head to work through blockage.
13. After blockage is cleared and the main is draining (Decrease Throttle, disengage hose reel (pump control to OFF/ hose reel/lever to OFF)
14. After manhole(s) have drained, follow steps 1 to 5 to continue upstream jetting to next manhole
15. Jet Downstream using Control Joystick
16. Black Leader Hose indicates jet head is 20 feet from manhole
17. Decrease Throttle, disengage hose reel (pump control to OFF/ hose reel/lever to OFF)
18. Retrieve remaining hose
19. Turn off Secondary motor if done with Jetting and Vacuuming VACUUM PROCEDURE:
1. Main truck engine ON Secondary Motor ON
2. Engage Joystick to boom on display screen
3. Unlatch boom from Support Bracket
4. Attach vacuum tubes to vacuum hose using clamps
5. Engage Vacuum with display or have in Work mode/Vacuum breaker ON
6. Control boom Joystick in boom mode, pull trigger to control while jetting
7. Control vacuum with screen controls and Joystick left side buttons GREEN Throttle up, RED Throttle down or toggle switch up or down Higher the Throttle stronger the Vacuum
8. Use Joystick to move Vacuum tube to location needed
9. When finished Throttle down
10. Remove Vacuum tubes and clamps
11. Relatch boom to Support Bracket
12. EXCAVATING:
1. Display control – vacuum - make sure in work mode/vacuum breaker ON
2. Dirt and mud should have water added when sucking to prevent the tubes, hose and boom from getting clogged
3. Low pressure wand– ball valves x2 for low pressure, one valve on the front passenger bumper second near hose reel
4. High pressure hose – large ball valve near reel
5. Pump control to ON
6. Turn off reverse steps – Pump control to OFF, turn all ball valves to original position
DUMPING AND CLEAN UP:
1. VAC-CON should be cleaned after each use
2. VAC-CON should be dumped at Rabello dump site, right hand side
3. VAC-CON should be dewatered in a manhole using the blue dump hose before emptying the tank
a. To dewater tank, turn on secondary motor and check for overhead obstructions
b. Back up to manhole and place blue dump hose into open manhole c. Open blue dump hose valve
d. Slowly raise tank to dewater
4. VAC-Con should be backed into the dump stall
5. To Dump debris from the tank check overhead for obstructions
6. The manual door locks for the tank should be released if equipped
7. Automatic door locks for the tank should be released (controls on passenger side)
8. Tank should be raised in order to dump solids and debris (controls on passenger side)
9. Inside of tank, door hatch and Exterior of VAC-CON should be washed well to remove additional solids and debris
10. Wash upper vacuum filters to be sprayed clean
11. Lower tank and engage all door locks for tank
12. Visually inspect all door locks have been engaged
13. Turn off secondary motor
ATTACHMENTS:
1. Low Pressure wand and hose
2. High pressure wand and hose
3. Pendant
SIGNATURE BLOCK:
CITY OF SANTA CLARA - SPILL EMERGENCY RESPONSE PLAN
SECTION 1: General Information / Background
Agency Name : City of Santa Clara
Cause Occurred in : Lateral____ Main Line ____ Force Main____ Incident Date : ____________ (MM/DD/YY)
Time of call: ____________
Time of Arrival At Spill Site: ____________
GPS Coordinates/Spill Orientation: _________________________________ Multiple Appearance Points: __________________________________________ Blockbook page: _______ Manhole #:_______
Weather Conditions: Wet______ Dry___ ___
Street Address/Site : _______ ___________________ Cross Street._________________________________ City :_Santa Clara________ County : ___Santa Clara____________ Zip Code :___________ # of Spill Appearance Points: ______ if more than 1, describe each appearance point in section 6 SECTION 2: Estimated and Calculated Spill amounts
Estimated Spill Rate Upon Time Of Arrival1 : _____________________ (GPM) Estimated Spill Start Time And Date2: __________________ Estimated Spill End Time And Date : __________________
Pipe Size:_____ (inches) Pipe Type/Material: _______
Estimated amount Spilled In Gallons3 : ______________________ (Numeric Only) Estimated amount Of Spill Mitigated
And Returned to Sanitary Sewer System
(not including the wash down water): ___________________ (gallons) SECTION 3: Spill Cause, Source, Destination
Spill Cause : ____ Blockage
____ Infrastructure Failure
____ Inflow Infiltration
____ Electrical Power Failure
____ Flow Capacity Deficiency
____ Natural Disaster
____ Bypass
____ Cause Unknown
____ Contractor
If Spill Cause Is Blockage, Please Specify :
____ Grease
____ Debris
____ Roots
____ Debris From Laterals
____ Vandalism
____ Animal Carcass
____ Construction Debris
____ Unknown
____ Multiple Causes
Please List :____________________________
Source Of Spill : ____ Manhole
____ Pipe
____ Clean Out
____ Pump Station
____ Flushing Inlet
____ Other
If Other, Please Specify :____________________________________________ Final Spill Destination: ____ Storm Drain
____ Captured In Storm drain
____ Building Structure
____ Yard/Lawn
____ Street/Curb & Gutter
____ Surface Water Impact; Name: _____________ Est. Spill Volume: _______ ____ Ground Water Impact
____ Unknown
SPILL REPORT - Page 1
SECTION 5: Incident Response and Notification
Incident Response:
Were response/ corrective actions taken: ____ Yes ____No if yes, please describe in section 6 Were clean-up actions taken: ____ Yes ____No
Were disinfection actions taking: ____ Yes ____No
Were samples taken: ____ Yes ____No
If yes, for what parameters? ________________________
Which regulatory agencies received results? ___________ Any ongoing investigation: ____ Yes ____No
If yes, expected completion date: _____________
Reason for investigation: ____________________
Any health or safety warnings posted: ____ Yes ____No
Suspected Responsible Party:
Name: _____________________ Address:_____________________Phone:___________________ City: _______________ County: _________________Zip Code:_______________ Notification: (Category 1 only when ≥ 1,000 gal. reaching surface waters), contact manager/supervisor) OES date called:__________
OES time called:___________
OES contact name:___________
OES Control Number: _________
SECTION 6: Additional Spill Calculation and Estimation information How Was Spill Start Time Determined?
SSCSC Manhole Overflow Gauge:_____
Math Calculation:_______
Spill Location and Spread (Visually assess using photography and GPS)
1. Draw a sketch
2. Photography for:
a. Drainage conveyance system entry location
b. Location(s) if discharge into surface waters
c. Extent of spill spread
d. Location(s) of clean up
3. Total Spill Volume Estimation calculation: Rectangle: L x W x D OR Circle: 3.14 x r 2 x D
4. Receiving Water Visual Observations:
a. Estimated spill volume entering the receiving water
b. Photography of:
i. Waterbody bank erosion
ii. Floating matter
iii. Water surface sheen
iv. (potentially from oil & grease)
v. Discoloration of receiving water, and
vi. Impact of the receiving water, Date of Completion: __________ Time: ________ Description of Multiple Spill Appearance Points, if any:
____________________________________________________________________ ____________________________________________________________________ Description of Spill Response Activities Date of Completion: __________ Time: ________ ________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ Description of Spill Corrective Action
_________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ SPILL REPORT - Page 2
Person Completed _____________________ Date ____/____/______ NOTES:
1 GPM is determined by using “CWEA Manhole Overflow Gauge” Worksheet 2 Estimated Start Time shall be determined by either of the following: Time of call, arrival time or information contained in section 6 3 Calculation: Spill Start Time – Spill End Time = Duration of spill (minutes) Duration of spill (minutes) X Spill rate (gpm) = Spill amount (gallons) SPILL REPORT - Page 3
Comments / Witnesses / Address / Time
____________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ For All Emergency Services - Central Dispatch
Emergency Services 911
Water and Sewer Department (408) 615-2000
Water and Sewer Emergencies (Electric Control) (408) 615-5640 Non-Emergency Dispatch (408) 615-5580
City Police Department - Traffic (408) 615-4760
County Health Officer
During Business Hours - Contact Dr. Sara H.
Cody, M.D.
(408) 792-3798 (Direct Line)
(408) 792-5040 (General Office)
After business hours, contact County
Communication and ask for the County Health
Office on-call
(408) 998-3438
Regional Water Board - Spill Notification (510) 622-2369 Regional Water Board - General Office: (510) 622-2300
Office of Emergency Services (800) 852-7550
PG&E (800) 743-5000
AT&T (800) 310-2355
Comcast XFinity (800) 945-2288
City Public Works/Engineering (408) 615-3000
City Fire Department - Emergency Services (408) 615-4900 City Street Department - Storm Drains (408) 615-3080
Additional Support for Emergency Operations
CITY OF SANTA CLARA SPILL EMERGENCY REPONSE PLAN
CITY OF SANTA CLARA
WATER AND SEWER UTILITIES DEPARTMENT
DIVISION: SEWER UTILITY
STANDARD OPERATION PROCEDURE:
SANITARY SEWER
OVERFLOW SAMPLING
City of Santa Clara • 1500 Warburton Ave • Phone 408-615-2000 City of Santa Clara • 1705 Martin Ave • Phone 408-615-2060
STANDARD
X
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 2 OF 20
S A N I T A R Y S E W E R O V E R F L O W S A M P L I N G S O P Revision History
Rev Description of Change Document
Owner/Editor
Release
Date
001 Initial Release: Sanitary Sewer Overflow Sampling SOP Diane Foronda 4/30/13 If you have any questions about this program, please contact your immediate Supervisor. This plan is maintained by the Compliance Manager. All Managers and Supervisors are to ensure the policies are carried out and the program is effective.
___________________________________
Assistant Director of Water & Sewer Utilities
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 3 OF 20
S T A N D A R D O P E R A T I N G P R O C E D U R E : S A N I T A R Y S E W E R O V E R F L O W I N G S A M P L I N G Table of Contents
1.0 Purpose and Scope 4
2.0 References 4
3.0 Acronyms and Definitions 4
4.0 Responsibilities 5
5.0 Procedure Requirements 6
5.1 When to take SSO Samples 6
5.2 Where to take SSO Samples 6
5.3 What to sample 6
pH
A Dissolved Oxygen (DO)
Fecal coliform
Ammonia
CAM17
5.4 How to take SSO Samples 6
5.5 A Equipment Care between Sample Locations 9
5.6 SSO Sample delivery to laboratory 9
6.0 Records 11
6.1 Standard Operating Procedure:Sanitary Sewer Overflow Sampling 11
6.2 Training and Documentation 11
7.0 Annual Inspection 12
8.0 Attachments
Attachment A: Sanitary Sewer Overflow (SSO) Form 13
Attachment B: Chain of Custody Report (Fecal Coliform) 14 Attachment C: Chain of Custody Report (CAM 17) 15
Attachment D: San Jose Treatment Plant Lab Form (Ammonia) 16 Attachment E: Driving Directions to Plant Lab 17
Attachment F: Driving Directions to San Mateo Lab 18
Attachment G: MSDS Sheets 20
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 4 OF 20
1. Purpose and Scope
1.1. In the event of a sanitary sewer overflow, our utility has developed, implemented and maintains a Standard Operation Procedure to test for various parameters in the event that overflows greater than or equal to 50 gallons reach surface waters.
1.2. The Standard Operation Procedure: Sanitary Sewage Overflow Sampling is developed and implemented for department staff to follow a correct and standardized procedure if an overflow were to occur, and the employer make procedure available to department employees.
1.3. The scope of this procedure applies to the Sanitary Sewer Operations & Maintenance division and Compliance division employees in the City of Santa Clara Water and Sewer Utilities Department.
2. References
2.1. References for this program include the following:
▪ Thermo Scientific User Guide for:
o Thermo Scientific Portable pH/RDO/DO Meter
o RDO Optical Dissolved Oxygen Sensor
o pH/ATC Triode
3. Acronyms and Definitions
Ammonia: A nutrient that contains nitrogen and hydrogen. Its chemical formula is NH3 in the un-ionized state and NH4
+
in the ionized form. Total ammonia is the sum of both
NH3 and NH4
+
. Ammonia can be converted to nitrite and nitrate by bacteria. The neutral, un-ionized form (NH3) is highly toxic.
CAM 17: A list of heavy metals in the California Administrative Manual, which includes antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, lead, mercury, molybdenum, nickel, selenium, silver, thallium, vanadium, and zinc Corrosive: A substance that causes visible destruction of, or irreversible alteration in, living tissue at the site of contact.
Department: City of Santa Clara Water and Sewer Utilities Dissolved Oxygen: Oxygen is measured in its dissolved form as dissolved oxygen (DO). If more oxygen is consumed that is produced, dissolved oxygen levels decline and some sensitive animals may move away, weaken, or die. DO levels vary with water temperature and altitude.
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 5 OF 20
Employee: Any regular, full-time, part-time or temporary employee employed by the department at any level in the organization, including Managers and Supervisors.
Fecal Coliform: Bacteria found in the intestinal tracts of mammals. Their presence in water or sludge is an indicator of possible contamination by pathogens Managers: All unclassified employees in the department, including the Director of Water and Sewer Utilities, Assistant Director of Water and Sewer Utilities, Water and Sewer Superintendent, Assistant Water and Sewer Superintendent, Compliance Manager, Principal Engineer and any employee in an acting role or out of class assignment as a manager within the Water and Sewer Utilities Department. pH: a measure of the number of hydrogen ions or a solution's acidity. In water, small numbers of water molecules will break apart into hydrogen ions (H+) and hydroxide ions (OH-). Other compounds entering the water may react with these, leaving an imbalance in the numbers of hydrogen and hydroxide ions. When more hydrogen ions react, more hydroxide ions are left in solution and the water is basic; when more hydroxide ions react, more hydrogen ions are left and the water is acidic.
POTW: Publicly Owned Treatment Works
Sampling Apparatus: Device used to obtain sample directly from surface water discharge site and transfer to appropriate containers.
Sanitary Sewer Overflow (SSO): A condition whereby untreated sewage is discharged into the environment prior to reaching the wastewater treatment plant.
Qualifying SSO: For purposes of this procedure a qualifying SSO shall mean any Sanitary Sewer Overflow greater than or equal to 50 gallons which reaches surface waters.
4. Responsibilities
4.1. Sanitary Sewer Operations & Maintenance Employees
▪ Are trained on how to correctly sample and record parameters needed for SSO discharge
▪ Follow standardized procedures
▪ Conduct sampling during a qualifying SSO event and notifying the San Mateo Lab upon becoming aware that sampling is necessary ▪ Request for additional sample kits and sample kit refills from the Compliance staff
▪ Notify Compliance staff for any equipment meter calibration, replacement, or maintenance which may include, but not limited to:
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 6 OF 20
▪ Additional AA batteries for pH and DO meter. Battery level is displayed on the meter screen.
▪ Annual replacement of DO Probe RDO Cap (meter will notify when the cap needs to be replaced)
▪ For calibration procedures, refer to the Thermo Scientific meter manual on City Drive
▪ Ensure sample kits are prepared and ready for use at all times. ▪ Direct any additional questions to the Compliance Manager
4.2. Compliance Manager
▪ Reviews, implements and maintains this SOP
▪ Trains and ensures that employees follow the procedures of this SOP
5. Procedure Requirements
5.1. When to take SSO Samples
5.1.1. When an SSO results in an overflow of 50 gallons or greater and reaches surface waters (Qualifying SSO)
5.1.2. When sufficient flow exists to collect a representative, uncontaminated sample and whether weather or other conditions allow City staff to safely obtain a sample
5.1.3. If by March 21, 2015, there are no qualifying SSO event that meets the criteria of 50 gallons or more reaching surface waters, the sample collection for CAM17 analysis will no longer be required.
5.2. Bring Sample Kits to Discharge Location
5.2.1. Two sample kits are available at the Yard. One will be stored in the Sewer Shop and the other will be stored at the Assistant Sewer Superintendent’s office.
5.2.2. The responding team shall bring the sample kit from the Sewer Shop.
5.2.3. As needed, the Superintendent(s) will bring the sample kit from the Assistant Sewer Superintendent’s Office.
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 7 OF 20
5.3. Where to take SSO Samples
5.3.1. Upstream of the surface water discharge location (within 150 feet if possible)
5.3.2. Surface water discharge location
5.3.3. Downstream of the surface water discharge location (within 150 feet if possible)
5.4. What to sample
5.4.1. Sample at each location identified in 5.3
5.4.2. Field Readings
5.4.2.1. pH
5.4.2.2. Dissolved Oxygen (DO)
5.4.3. Grab Samples
5.4.3.1. Fecal coliform
5.4.3.2. Ammonia
5.4.3.3. CAM17
5.5. How to take SSO Samples
5.5.1. Measuring Equipment Needed
5.5.1.1. Thermo Scientific Portable Reader (for pH and DO)
5.5.1.2. pH probe (Thermo Scientific ROSS Ultra pH/ATC Triode)
5.5.1.3. DO probe (Thermo Scientific RDO Optical Dissolved Oxygen Sensor)
▪ Calibration sleeve (should already be attached to DO probe) and stainless steel protective guard (used during sampling)
5.5.2. Equipment Checklist
5.5.2.1. Sampling apparatus
5.5.2.2. Distilled water to rinse pH and DO probes
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 8 OF 20
5.5.2.3. Potable water to rinse sampling apparatus
5.5.2.4. Ice packs
5.5.2.5. Permanent pen/marker
5.5.2.6. Nitrile gloves
5.5.2.7. 2 coolers (for Fecal coliform and Ammonia)
5.5.2.8. 1 box (for CAM17)
5.5.2.9. 3 – Site sampling bottle packs, each consisting of:
▪ 1 – Fecal coliform bottle (100mL)
▪ 1 – Plastic Ammonia bottle (500mL)
▪ 1 – Plastic CAM17 bottles (250mL)
5.5.3. Forms
5.5.3.1. SSO Form (Attachment A)
5.5.3.2. 3 - Chain of Custody Report (for each lab and River Watch)
5.5.4. Using sampling apparatus
5.5.4.1. Wear all safety and protective gears
5.5.4.2. Collect all samples using sampling apparatus
5.5.4.3. Transfer surface water collected by sampling apparatus into sample bottles
5.5.4.4. Do not rinse out any of the sample bottles as they all have certain preservatives or reagents inside. As such, do not use sample bottles to collect water from surface water directly.
5.5.5. pH and Dissolved Oxygen (DO) analyses
5.5.5.1. Conduct pH and DO tests within 15 minutes of grabbing samples using sampling apparatus.
5.5.5.2. Perform both readings simultaneously using appropriate probes connected to Thermo Scientific Portable Reader
▪ Ensure both probes are connected to the top of the Reader (pH→ATC/COND; DO→DO/RDO)
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 9 OF 20
▪ Turn Reader on, wait for Reader to stabilize
▪ Loosen storage bottle solution cap to remove pH probe and immediately insert into water collected with sampling
apparatus, probe must be immersed in solution at all times ▪ Unscrew white calibration sleeve from DO probe and attach stainless steel protective guard
▪ Insert DO probe into the same water sample as the pH probe, being careful to not touch the sensor on the bottom of the probe
▪ Press “Measure”
▪ Wait for readings to stabilize and record readings under pH and DO on SSO form (Attachment A)
▪ Carefully rinse pH probe with distilled water and return to storage bottle solution, ensuring storage bottle cap is screwed on tight
▪ Carefully rinse DO probe with distilled water
5.5.6. Fecal coliform samples
5.5.6.1. Record date and time on bottle label
5.5.6.2. Remove plastic cap and fill bottle past the 100mL fill line with water from sampling apparatus
5.5.6.3. Take care not to overfill bottle or contaminate container, leave enough head space to allow proper mixing of the sample
5.5.6.4. Replace bottle cap immediately and return to Fecal Coliform cooler
5.5.7. Ammonia samples
5.5.7.1. Record date and time on bottle label
5.5.7.2. Remove cap from plastic bottle
5.5.7.3. Fill bottle up to its shoulder with water collected with sampling apparatus
5.5.7.4. Replace cap and return to Ammonia cooler
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 10 OF 20
5.5.8. CAM17 samples
5.5.8.1. Record date and time on bottle label
5.5.8.2. Remove cap from plastic bottle
5.5.8.3. Fill bottle up to its shoulder with water collected with sampling apparatus
5.5.8.4. Take care not to overfill bottle (contains corrosive material, may cause skin irritation)
5.5.8.5. Replace cap and return to CAM17 box
5.6. Equipment Care between Sample Locations
5.6.1. Rinse sampling apparatus with potable water upon finishing at each site before continuing on to the next sampling site
5.6.2. After the last site, remove stainless steel protective guard from DO probe and replace with white calibration sleeve. Open cap of calibration sleeve and moisten the gray sponge with distilled water before continued storage
5.6.3. Return completed Sanitary Sewer Overflow forms to the Compliance Manager
5.6.4. After the last samples and upon returning to the Yard, rinse sampling equipment with potable water and store sampling kit(s) to their storage location.
5.7. SSO Sample delivery to laboratory
5.7.1. Fecal coliform cooler
5.7.1.1. Place ice packs in cooler to ensure an environment of < 10ºC (50ºF)
5.7.1.2. Make a copy of the Chain of Custody Report (Attachment B) for the Compliance Manager and include original in cooler
5.7.1.3. Samples need to be delivered to the laboratory within 4 hours of sample collection
5.7.1.4. Return cooler to Yard and arrange pick up by San Mateo County Lab Courier.
5.7.1.5. Provide location where sample is to be picked up STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 11 OF 20
5.7.1.6. San Mateo County Laboratory Phone Numbers:
▪ Business Hours – Lab Office: (650)-573-2500; June Wong:
(650) 573-2456
▪ After Hours – June Wong (Cell): (650) 339-2322; (Home):
(650) 594-1338
o Sangeeta Singh – (650) 235-6755
o Zelda Berrada – (650) 703-3935; (617) 512-9949; or
(510) 778-1362
5.7.1.7. In the event that the courier service is not available to deliver samples within the 4-hour time frame, City Staff will deliver the samples to the Public Health Laboratory at:
▪ 225 West 37th Ave, Room 113. San Mateo, CA 94403
5.7.2. Ammonia cooler
5.7.2.1. Place ice packs in cooler to ensure an environment of < 6ºC (39.2ºF)
5.7.2.2. Make a copy of the Chain of Custody Report (Attachment D) for the Compliance Manager and include original in cooler
5.7.2.3. Sample has up to 28-day holding time.
5.7.2.4. Deliver cooler to Treatment Plant’s Environmental Services Department Laboratory at:
▪ 700 Esteros Rd. San Jose, CA 95134 (see Attachment E for driving directions and lab location)
▪ Phone Number: (408) 945-3725
▪ Business Hours: Monday through Friday (7:00AM – 5:00 PM) ▪ After Hours/Weekends: Store in refrigerator located in Assistant Water & Sewer Superintendent’s Office and hold until next available business day.
5.7.3. CAM17 box
5.7.3.1. Make a copy of the Chain of Custody Report (Attachment C) for the Compliance Manager and include original in box
5.7.3.2. Keep samples in ambient temperature. No ice is needed.
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 12 OF 20
5.7.3.3. Sample has 6 months holding time
5.7.3.4. Return box to City Hall or release samples to Assistant Superintendent. Contact Compliance Manager to arrange pick up by River Watch.
5.8. Coordination with Compliance Staff
5.8.1. Notify Compliance Staff regarding the SSO.
5.8.2. Submit Chain of Custody forms (fecal coliform, ammonia and CAM 17) and CAM 17 samples to the Compliance Manager.
5.8.3. Compliance Staff to examine Sewer Overflow Sampling kit(s) and refill any materials including forms. Check pH storage reagent and replenish as necessary. Order more sample bottles as necessary from the respective laboratories.
6. Records
6.1. Standard Operating Procedure: Sanitary Sewer Overflow Sampling
6.1.1. This procedure will be reviewed by the Compliance Manager annually.
6.1.2. All records are to be retained for a minimum of 10 years for compliance purposes.
6.2 Training and Documentation
6.2.1. The Compliance Manager will periodically conduct sampling training for new employees or as a refresher.
7. Annual Inspection
7.1. On an annual basis, Compliance Staff shall inspect the two sample kits and perform the following:
7.1.1. Replace membranes on the DO probes.
7.1.2. Calibrate pH and DO probes.
7.1.3. Check pH and DO meter batteries.
7.1.4. Order more sample bottles as necessary.
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 13 OF 20 Attachment A: Sanitary Sewer Overflow Form
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 14 OF 20 Attachment B: Chain of Custody Report (Fecal Coliform San Mateo Lab) STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 15 OF 20 Attachment C: Chain of Custody Report (CAM 17 – For Pick Up) STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 16 OF 20 Attachment D: San Jose Treatment Plant Lab Form (Ammonia) STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 17 OF 20 Attachment E: Driving Directions to Plant Lab
Address: San Jose/Santa Clara Water Pollution Control Plant. 700 Los Esteros Road, San Jose
Business Hours: Monday – Friday. 7 AM – 5 PM
▪ Stop at Main Gate
▪ Have Security Guard call Environmental Services Lab to grant access into facility at (408) 945-3725
▪ Continue into facility and park at the Environmental Services Lab parking lot STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 18 OF 20 Attachment F: Driving Directions to San Mateo Lab
STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 19 OF 20 STANDARD NO. X
SANITARY SEWER OVERFLOW SAMPLING REV. 001 PAGE 20 OF 20 Attachment G: MSDS Sheets
Revised on 12/10/2010 Page 1 of 7
Material Safety Data Sheet
BDH3068-500MLP
BDH3070-2.5LPC
BDH3072-2.5LG
BDH3074-3.8LP
BDH3076-19L
BDH3078-56L
BDH3088-111L
BDH3090-185L
TXBDH307438CPI
Sulfuric Acid
1. PRODUCT AND COMPANY IDENTIFICATION
Product Name: Sulfuric Acid
Synonyms/Generic Names: Oil of Vitriol, Battery Acid, Sulphuric Acid, Dihydrogen Sulfate Product Use: Industrial, Manufacturing or Laboratory use Manufacturer: Columbus Chemical Industries, Inc.
N4335 Temkin Rd. Columbus, WI. 53925
For More Information Call: 920-623-2140 IN CASE OF EMERGENCY CALL: CHEMTREC (Monday – Friday 8:00-4:30) (24 Hours/Day, 7 Days/Week) 800-424-9300 703-527-3887
2. COMPOSITION/INFORMATION ON INGREDIENTS
Weight % Component CAS # EINECS# /
ELINCS# Classification*
95 – 98% Sulfuric Acid 7664-93-9 231-639-5 C; R35, **
Balance Water 7732-18-5 N/A N/A
*Symbol and R phrase according to EC Annex1
** Subject to the reporting requirements of SARA Title III Section 313
3. HAZARDS IDENTIFICATION
Clear, colorless solution with caustic odor.
R35 – Causes severe burns.
S1/2, S26, S30, S45
Routes of Entry: Skin, eyes, inhalation and ingestion.
Ingredients found on carcinogen lists:
INGREDIENT NAME NTP STATUS IARC STATUS OSHA LIST ACGIH
Sulfuric Acid Known Group 1 Not Listed A2
Revised on 12/10/2010 Page 2 of 7
4. FIRST AID INFORMATION
Inhalation: Inhalation of mists can cause corrosive action on mucous membranes. Symptoms include burning, choking, coughing, wheezing, laryngitis, shortness of breath, headache or nausea.
Move casualty to fresh air and keep at rest. Get medical attention if symptoms persist.
Eyes: Contact rapidly causes severe damage. Symptoms include eye burns, watering eyes. Permanent damage to cornea may result. In case of eye contact, rinse with plenty of water and seek medical attention immediately.
Skin: Severe and rapid corrosion from contact. Extent of damage depends on duration of contact.
Symptoms include burning, itching, redness, inflammation and/or swelling of exposed tissues. harmful if absorbed through skin. Immediately flush with plenty of water for at least 15 minutes while removing contaminated clothing and wash using soap. Get medical attention immediately.
Ingestion: Do Not Induce Vomiting! Severe and rapid corrosive burns of the mouth, gullet and gastrointestinal tract will result if swallowed. Symptoms include burning, choking, nausea, vomiting and severe pain. Wash out mouth with water and give a glass of water or milk. Get medical attention immediately.
5. FIRE-FIGHTING MEASURES
FLAMMABLE PROPERTIES:
Flash Point: Not Flammable
Flash Point method: Not Applicable
Autoignition Temperature: Not Applicable
Upper Flame Limit (volume % in air): Not Applicable
Lower Flame Limit (volume % in air): Not Applicable
Extinguishing Media: Product is not flammable. Use appropriate media for adjacent fire. Cool containers with water, keep away from common metals.
Special fire-fighting procedures: Wear self-contained, approved breathing apparatus and full protective clothing, including eye protection and boots. Material can react violently with water (spattering and misting) and react with metals to produce flammable hydrogen gas.
Hazardous combustion products: Emits toxic fumes under fire conditions. (See also Stability and Reactivity section).
Unusual fire and explosion hazards: Contact with organic material may cause fire. Material can react with metals to produce flammable hydrogen gas.
6. ACCIDENTAL RELEASE MEASURES
Personal precautions: See section 8 for recommendations on the use of personal protective equipment.
Environmental precautions: Cleanup personnel need personal protection from inhalation and skin/eye contact. Evacuate and ventilate the area. Prevent spillage from entering drains. Cautiously add water to spill, taking care to avoid splashing and spattering. Neutralize diluted spill with soda ash or lime.
Absorb neutralized spill with vermiculite or other inert absorbent material, then place in a suitable container for disposal. Clean surfaces thoroughly with water to remove residual contamination. Any release to the environment may be subject to federal/national or local reporting requirements.
Dispose of all waste or cleanup materials in accordance with local regulations. Containers, even when empty, will retain residue and vapors.
Revised on 12/10/2010 Page 3 of 7
7. HANDLING AND STORAGE
Normal handling: See section 8 for recommendations on the use of personal protective equipment. Use with adequate ventilation. Wash thoroughly after using. Keep container closed when not in use.
Storage: Store in cool, dry well ventilated area. Keep away from incompatible materials (see section 10 for incompatibilities). Drains for storage or use areas for this material should have retention basins for pH adjustment and dilution of spills.
8. EXPOSURE CONTROLS / PERSONAL PROTECTION
Occupational exposure controls: (consult local authorities for acceptable exposure limits) Chemical name Regulatory List Value and type
Sulfuric Acid UK OES 1 mg/m3 TWA
USA OSHA PEL 1 mg/m3 TWA
STEL 3 mg/m3 (15 minutes)
USA ACGIH 1 mg/m3 TLV
USA NIOSH 1 mg/m3 REL
USA OSHA IDLH 15 mg/m3
VME France 1 mg/m3 TWA 8 hr
VLE France (STEL) 3 mg/m3 (15 minutes)
TWA: Time Weighted Average over 8 hours of work.
TLV: Threshold Limit Value over 8 hours of work.
REL: Recommended Exposure Limit
STEL: Short Term Exposure Limit during 15 minutes.
IDLH: Immediately Dangerous to Life or Health
Ventilation: Provide local exhaust, preferably mechanical.
Respiratory protection: If necessary use an approved respirator with acid vapor cartridges.
Eye protection: Wear chemical safety glasses with a face shield for splash protection.
Skin and body protection: Wear neoprene or rubber gloves, apron and other protective clothing appropriate to the risk of exposure.
Other Recommendations: Provide eyewash stations, quick-drench showers and washing facilities accessible to areas of use and handling. Have supplies and equipment for neutralization and running water available.
Revised on 12/10/2010 Page 4 of 7
9. PHYSICAL AND CHEMICAL PROPERTIES
Appearance: Clear, colorless to slight yellow liquid
Physical state: Liquid
Odor: Caustic
Odor Threshold: Unknown
Specific Gravity: 1.8427
pH: 1
Melting Point/Freezing Point: 10°C (51°F)
Boiling Point/Range: 330°C (626°F)
Flammability: Not Flammable (See section 5)
Flash point: Not Flammable (See section 5)
Evaporation Rate (Butyl Acetate =1): Not Available
Explosive Limits: Not Explosive (See section 5)
Vapor Pressure (at 20ºC): Not Available
Vapor Density (air =1): 3.4
Solubility: Completely soluble in water
Partition coefficient/n-octanol/water: Not Available
% Volatile: Not Available
Autoignition Temperature: See section 5
10. STABILITY AND REACTIVITY
Stability: Stable
Conditions to avoid: Uncontrolled addition of water.
Incompatibility: Moisture, bases, halides, organic material, metals, carbides, cyanides, chlorates, nitrates, picrates, permanganate, peroxides, zinc iodide, azides, perchlorates, phosphorus, nitrites and finely powdered metals.
Hazardous decomposition products: Oxides of sulfur, Hydrogen sulfide gas.
Hazardous polymerization: Will not occur.
11. TOXICOLOGICAL INFORMATION
Acute Effects: See section 4 for symptoms of exposure and effects. Likely routes of exposure are skin, eyes and inhalation.
Target organs: Teeth, blood, liver, bone marrow and cardiovascular system.
Acute Toxicity Data:
Sulfuric acid Oral LD50 (rat): 2140 mg/kg
LC50 (rat): 510 mg/m3
Chronic Effects: Sulfuric Acid mists are listed as a possible carcinogen.
Teratogenicity: Inhalation (rabbit) 20 mg/m3/7hrs, 6-18 days pregnant, result-musculoskeletal deformities.
Mutagenicity: Hamster, 4 MMOL/L, ovary.
Embryotoxicity: Not Available
Synergistic Products/Effects: Not Available
Revised on 12/10/2010 Page 5 of 7
12. ECOLOGICAL INFORMATION
Ecotoxicity (aquatic and terrestrial): Data not available Persistence and Degradability: Data not available
Bioaccumulative Potential: Data not available
Mobility in Soil: Data not available
Other Adverse Effects: Data not available
13. DISPOSAL CONSIDERATIONS
RCRA:
Hazardous waste? Yes RCRA ID number: DOO2
Waste Residues: Carefully dilute with water, neutralize per spill procedures in section 6. Neutralized material may be flushed to sewer (REGULATIONS PERMITTING!) or disposed of through a licensed contractor. Users should review their operations in terms of the applicable federal/nation or local regulations and consult with appropriate regulatory agencies before discharging or disposing of waste material.
Product containers: Containers, if thoroughly cleaned, preferably by rinsing three times and handling the rinse water as waste residues, may be disposed of or recycled as non-hazardous waste. Users should review their operations in terms of the applicable federal/national or local regulations and consult with appropriate regulatory agencies before discharging or disposing of waste material.
The information offered in section 13 is for the product as shipped. Use and/or alterations to the product may significantly change the characteristics of the material and alter the waste classification and proper disposal methods.
14. TRANSPORTATION INFORMATION
DOT: UN1830, Sulfuric Acid, 8, pg II
TDG: UN1830, Sulfuric Acid, 8, pg II
PIN: Not Available
IDMG: UN1830, Sulphuric Acid, 8, pg II
Marine Pollutant: No
IATA/ICAO: UN1830, Sulphuric Acid, 8, pg II
RID/ADR: Class 8, Item 1(b), corrosive, Kemler plate: 80/1830 Revised on 12/10/2010 Page 6 of 7
15. REGULATORY INFORMATION
TSCA Inventory Status: All ingredients are listed on the TSCA inventory.
Federal and State Regulations:
Pennsylvania RTK: Sulfuric Acid
Massachusetts RTK: Sulfuric Acid
SARA 302/304/311/312 extremely hazardous substances: Sulfuric Acid SARA 313 toxic chemical notification and release reporting: Sulfuric Acid CERCLA: Hazardous Substances: Sulfuric Acid
California Proposition 65: Yes - Strong inorganic acid mists containing sulfuric acid.
WHMIS Canada: Class E - corrosive liquid.
DSCL (EEC): R35 – Causes severe burns.
HMIS (U.S.A.)
National Fire
Protection
Association (U.S.A.) Flammability
0 Health 3 2 Reactivity
Specific hazard
Protective Equipment:
ADR (Europe):
Health Hazard 3
Fire Hazard 0
Reactivity 3
Revised on 12/10/2010 Page 7 of 7
TDG (Canada):
DSCL (Europe):
16. OTHER INFORMATION
Current Issue Date: December 10, 2010
Prepared by: S. Brock
Disclaimer: Columbus Chemical Industries, Inc. (“Columbus”) believes that the information herein is factual but is not intended to be all inclusive. The information relates only to the specific material designated and does not relate to its use in combination with other materials or its use as to any particular process. Because safety standards and regulations are subject to change and because Columbus has no continuing control over the material, those handling, storing or using the material should satisfy themselves that they have current information regarding the particular way the material is handled, stored or used and that the same is done in accordance with federal, state and local law. COLUMBUS MAKES NO WARRANTY, EXPRESS OR IMPLIED, INCLUDING (WITHOUT LIMITATION)
WARRANTIES WITH RESPECT TO THE COMPLETENESS OR CONTINUING ACCURACY OF THE INFORMATION CONTAINED HEREIN OR WITH RESPECT TO FITNESS FOR ANY PARTICULAR USE.
Material Safety Data Sheet
Nitric acid, 20-70%
ACC# 16550
Section 1 - Chemical Product and Company Identification MSDS Name: Nitric acid, 20-70%
Catalog Numbers: AC124660000, AC124660010, AC124660011, AC124660025, AC124660026, AC124665000, AC124665001, AC133620000, AC133620010, AC133620011, AC133620025, AC133620026, AC424000000, AC424000025, AC424000026, AC424000250, AC424005000, AC424005001, AC613205000, A198C-212, A198C4X212, A200-212, A200-500, A200-500LC, A200-612GAL, A200212LC, A200C-212, A200C212EA, A200C212LC, A200C4X-212, A200C4X212L, A200S-212, A200S-500, A200S212LC, A200SI-212, A206C-212, A206C4X-212, A467-1, A467-2, A467-250, A467-500, A483-212, A509-212, A509-212LC, A509-500, A509SK-212, A509SK212LC, MCC-030822, NC9596579, S719721, S71972SC Synonyms: Azotic acid; Engraver's acid; Aqua fortis.
Company Identification:
Fisher Scientific
1 Reagent Lane
Fair Lawn, NJ 07410
For information, call: 201-796-7100
Emergency Number: 201-796-7100
For CHEMTREC assistance, call: 800-424-9300
For International CHEMTREC assistance, call: 703-527-3887 Section 2 - Composition, Information on Ingredients
CAS# Chemical Name Percent EINECS/ELINCS
7732-18-5 Water 30-80 231-791-2
7697-37-2 Nitric acid 20-70 231-714-2
Section 3 - Hazards Identification
EMERGENCY OVERVIEW
Appearance: clear to yellow liquid.
Danger! May be fatal if inhaled. Causes severe eye and skin burns. Causes severe respiratory and digestive tract burns. Strong oxidizer. Contact with other material may cause a fire. Acute pulmonary edema or chronic obstructive lung disease may occur from inhalation of the vapors of nitric acid. Corrosive to metal.
Target Organs: Lungs, eyes, skin, mucous membranes.
Potential Health Effects
Eye: Causes severe eye burns. Direct contact with liquid may cause blindness or permanent eye damage.
Skin: Causes skin burns. May cause deep, penetrating ulcers of the skin. Concentrated nitric acid dyes human skin yellow on contact.
Ingestion: May cause severe and permanent damage to the digestive tract. Causes gastrointestinal tract burns.
May cause perforation of the digestive tract. May cause systemic effects.
Inhalation: Effects may be delayed. Causes chemical burns to the respiratory tract. Inhalation may be fatal as a result of spasm, inflammation, edema of the larynx and bronchi, chemical pneumonitis and pulmonary edema.
Aspiration may lead to pulmonary edema. May cause systemic effects. May cause acute pulmonary edema, asphyxia, chemical pneumonitis, and upper airway obstruction caused by edema. Depending on the conditions, the vapor or fumes of nitric acid may actually be a mixture of nitric acid and various oxides of nitrogen. The composition may vary with temperature, humidity, and contact with other organic materials.
Chronic: Exposure to high concentrations of nitric acid vapor may cause pneuomonitis and pulmonary edema which may be fatal. Symptoms may or may not be delayed. Continued exposure to the vapor & mist of nitric acid may result in a chronic bronchitis, & more severe exposure results in a chemical pneumonitis. The vapor & mists of nitric acid may erode the teeth, particularly affecting the canines & incisors.
Section 4 - First Aid Measures
Eyes: Get medical aid immediately. Do NOT allow victim to rub eyes or keep eyes closed. Extensive irrigation with water is required (at least 30 minutes).
Skin: Get medical aid immediately. Immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. Destroy contaminated shoes.
Ingestion: Do not induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
Inhalation: Get medical aid immediately. Remove from exposure and move to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Do NOT use mouth-to-mouth resuscitation. If breathing has ceased apply artificial respiration using oxygen and a suitable mechanical device such as a bag and a mask.
Notes to Physician: Treat symptomatically and supportively.
Section 5 - Fire Fighting Measures
General Information: As in any fire, wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Strong oxidizer. Contact with other material may cause fire. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. Use water spray to keep fire-exposed containers cool. May react with metal surfaces to form flammable and explosive hydrogen gas. Approach fire from upwind to avoid hazardous vapors and toxic decomposition products.
Extinguishing Media: Use extinguishing media most appropriate for the surrounding fire.
Flash Point: Not applicable.
Autoignition Temperature: Not available.
Explosion Limits, Lower:Not available.
Upper: Not available.
NFPA Rating: (estimated) Health: 4; Flammability: 0; Instability: 0; Special Hazard: OX Section 6 - Accidental Release Measures
General Information: Use proper personal protective equipment as indicated in Section 8.
Spills/Leaks: Avoid runoff into storm sewers and ditches which lead to waterways. Clean up spills immediately, observing precautions in the Protective Equipment section. Absorb spill using an absorbent, non-combustible material such as earth, sand, or vermiculite. Do not use combustible materials such as sawdust. Provide ventilation. Evacuate unnecessary personnel. Approach spill from upwind. Use water spray to cool and disperse vapors and protect personnel.
Section 7 - Handling and Storage
Handling: Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Do not breathe dust, mist, or vapor. Do not get in eyes, on skin, or on clothing. Keep container tightly closed. Avoid contact with clothing and other combustible materials. Discard contaminated shoes. Do not use with metal spatula or other metal items. Use only with adequate ventilation or respiratory protection.
Storage: Do not store near combustible materials. Do not store in direct sunlight. Keep container closed when not in use. Store in a cool, dry, well-ventilated area away from incompatible substances. Keep away from metals.
Store away from alkalies. Separate from organic materials. Inspect periodically for damage or evidence of leaks or corrosion.
Section 8 - Exposure Controls, Personal Protection
Engineering Controls: Facilities storing or utilizing this material should be equipped with an eyewash facility and a safety shower. Use adequate general or local exhaust ventilation to keep airborne concentrations below the permissible exposure limits. Use a corrosion-resistant ventilation system.
Exposure Limits
Chemical Name ACGIH NIOSH OSHA - Final PELs
Water none listed none listed none listed
Nitric acid 2 ppm TWA; 4 ppm STEL 2 ppm TWA; 5 mg/m3 TWA 25 ppm IDLH 2 ppm TWA; 5 mg/m3 TWA
OSHA Vacated PELs: Water: No OSHA Vacated PELs are listed for this chemical. Nitric acid: 2 ppm TWA; 5 mg/m3 TWA
Personal Protective Equipment
Eyes: Wear chemical splash goggles and face shield.
Skin: Wear butyl rubber gloves, apron, and/or clothing.
Clothing: Wear appropriate clothing to prevent skin exposure.
Respirators: Follow the OSHA respirator regulations found in 29 CFR 1910.134 or European Standard EN 149.
Use a NIOSH/MSHA or European Standard EN 149 approved respirator if exposure limits are exceeded or if irritation or other symptoms are experienced.
Section 9 - Physical and Chemical Properties
Physical State: Liquid
Appearance: clear to yellow
Odor: strong odor - acrid odor - suffocating odor
pH: 1.0 (0.1M soln)
Vapor Pressure: 51 mm Hg @ 25 deg C
Vapor Density: 2.17 (air=1)
Evaporation Rate:Not available.
Viscosity: 0.761 cps @ 25 deg C
Boiling Point: 86 deg C
Freezing/Melting Point:-42 deg C
Decomposition Temperature:Not available.
Solubility: Soluble in water.
Specific Gravity/Density:1.4
Molecular Formula:HNO3
Molecular Weight:63.01
Section 10 - Stability and Reactivity
Chemical Stability: Stable. Decomposes when in contact with air, light, or organic matter. The yellow color is due to release of nitrogen dioxide on exposure to light.
Conditions to Avoid: High temperatures, light, confined spaces.
Incompatibilities with Other Materials: Metals, reducing agents, strong bases, acetic acid, alcohols, acetone, aniline, hydrogen sulfide, metal powders, carbides, aldehydes, organic solvents, combustible materials, chromic acid, flammable liquids, cyanides, sulfides, Incompatible with many substances.
Hazardous Decomposition Products: Nitrogen oxides.
Hazardous Polymerization: Has not been reported.
Section 11 - Toxicological Information
RTECS#:
CAS# 7732-18-5: ZC0110000
CAS# 7697-37-2: QU5775000; QU5900000
LD50/LC50:
CAS# 7732-18-5:
Oral, rat: LD50 = >90 mL/kg;
.
CAS# 7697-37-2:
Inhalation, rat: LC50 = 260 mg/m3/30M;
Inhalation, rat: LC50 = 130 mg/m3/4H;
Inhalation, rat: LC50 = 67 ppm(NO2)/4H;
.
Carcinogenicity:
CAS# 7732-18-5: Not listed by ACGIH, IARC, NTP, or CA Prop 65.
CAS# 7697-37-2: Not listed by ACGIH, IARC, NTP, or CA Prop 65.
Epidemiology: No information found
Teratogenicity: No information found
Reproductive Effects: No information found
Mutagenicity: No information found
Neurotoxicity: No information found
Other Studies:
Section 12 - Ecological Information
Ecotoxicity: No data available. No information available.
Environmental: Terrestial: During transport through the soil, nitric acid will dissolve some of the soil material, in particular, the carbonate based materials. The acid will be neutralized to some degree with adsorption of the proton also occurring on clay materials. However, significant amounts of acid are expected to remain for transport down toward the ground water table. Upon reaching the ground water table, the acid will continue to move, now in the direction of the ground water flow.
Physical: No information available.
Other: No information available.
Section 13 - Disposal Considerations
Chemical waste generators must determine whether a discarded chemical is classified as a hazardous waste. US EPA guidelines for the classification determination are listed in 40 CFR Parts 261.3. Additionally, waste generators must consult state and local hazardous waste regulations to ensure complete and accurate classification.
RCRA P-Series: None listed.
RCRA U-Series: None listed.
Section 14 - Transport Information
US DOT Canada TDG
Shipping Name: NITRIC ACID NITRIC ACID
Hazard Class: 8 8
UN Number: UN2031 UN2031
Packing Group: II II
Section 15 - Regulatory Information
US FEDERAL
TSCA
CAS# 7732-18-5 is listed on the TSCA inventory.
CAS# 7697-37-2 is listed on the TSCA inventory.
Health & Safety Reporting List
None of the chemicals are on the Health & Safety Reporting List.
Chemical Test Rules
None of the chemicals in this product are under a Chemical Test Rule.
Section 12b
None of the chemicals are listed under TSCA Section 12b.
TSCA Significant New Use Rule
None of the chemicals in this material have a SNUR under TSCA.
CERCLA Hazardous Substances and corresponding RQs
CAS# 7697-37-2: 1000 lb final RQ; 454 kg final RQ
SARA Section 302 Extremely Hazardous Substances
CAS# 7697-37-2: 1000 lb TPQ
SARA Codes
CAS # 7697-37-2: immediate, delayed, fire.
Section 313
This material contains Nitric acid (CAS# 7697-37-2, 20-70%),which is subject to the reporting requirements of Section 313 of SARA Title III and 40 CFR Part 373.
Clean Air Act:
This material does not contain any hazardous air pollutants.
This material does not contain any Class 1 Ozone depletors.
This material does not contain any Class 2 Ozone depletors.
Clean Water Act:
CAS# 7697-37-2 is listed as a Hazardous Substance under the CWA.
None of the chemicals in this product are listed as Priority Pollutants under the CWA.
None of the chemicals in this product are listed as Toxic Pollutants under the CWA.
OSHA:
CAS# 7697-37-2 is considered highly hazardous by OSHA.
STATE
CAS# 7732-18-5 is not present on state lists from CA, PA, MN, MA, FL, or NJ.
CAS# 7697-37-2 can be found on the following state right to know lists: California, New Jersey, Pennsylvania, Minnesota, Massachusetts.
California Prop 65
California No Significant Risk Level: None of the chemicals in this product are listed.
European/International Regulations
European Labeling in Accordance with EC Directives
Hazard Symbols:
C
Risk Phrases:
R 35 Causes severe burns.
Safety Phrases:
S 23 Do not inhale gas/fumes/vapour/spray.
S 26 In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.
S 36 Wear suitable protective clothing.
S 45 In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible).
WGK (Water Danger/Protection)
CAS# 7732-18-5: No information available.
CAS# 7697-37-2: 1
Canada - DSL/NDSL
CAS# 7732-18-5 is listed on Canada's DSL List.
CAS# 7697-37-2 is listed on Canada's DSL List.
Canada - WHMIS
This product has a WHMIS classification of E, C, D1A.
This product has been classified in accordance with the hazard criteria of the Controlled Products Regulations and the MSDS contains all of the information required by those regulations.
Canadian Ingredient Disclosure List
CAS# 7697-37-2 is listed on the Canadian Ingredient Disclosure List.
Section 16 - Additional Information
MSDS Creation Date: 9/30/1998
Revision #16 Date: 2/11/2008
The information above is believed to be accurate and represents the best information currently available to us. However, we make no warranty of merchantability or any other warranty, express or implied, with respect to such information, and we assume no liability resulting from its use. Users should make their own investigations to determine the suitability of the information for their particular purposes. In no event shall Fisher be liable for any claims, losses, or damages of any third party or for lost profits or any special, indirect, incidental, consequential or exemplary damages, howsoever arising, even if Fisher has been advised of the possibility of such damages.
Appendix I
FOG Program Materials and Handouts
Wipe pots, pans, and
work areas prior to
washing.
Limpie las ollas, sarténes,
y áreas de trabajo con
una toalla antes de
lavarlos.
Do not pour cooking
residue directly
into the drain.
No tire residuos de
cocinar directamente
en el desagüe.
Do not pour waste oil
directly into the drain.
No tire aceite
usado directamente
en el desagüe.
Do not wash floor
mats where water will
run off directly into
the storm drain.
No lave tapetes de piso
en un lugar donde el agua
corra hacia el desagüe.
1 2 2
3 3
4 4
1 Dispose of food waste
directly into the trash.
Deseche los desperdicios
de comida en el bote
de basura.
Do not dispose of
food waste into the
garbage disposal.
No ponga desperdicios
de comida en el moledor
de comida.
Clean mats inside
over a utility sink.
Limpie los tapetes de
piso dentro de una tina
o fregador.
Collect waste oil and store
for recycling.
Junte el aceite usado
y guárdelo para que
sea reciclado.
THE
RIGHT WAY
THE
WRONG WAY
Courtesy of Sanitation Districts of Los Angeles County
La Forma Incorrecta La Forma Correcta
Managing
FATS, OIL and GREASE
“It’s Easier than YOU Think!”
Appendix I
put cooking oil,
grease, or greasy food
down the drain.
pour cooled grease
into disposable
containers and place
them into the garbage
once it has hardened.
Use a paper towel to
wipe and absorb
grease or oil on dishes
and pots before
washing them.
If you see a sewer overflow call
408.615.2000 immediately!
Grease was Removed From
Sewer Lines In Your Area!
put cooking oil,
grease, or greasy food
down the drain.
pour cooled grease
into disposable
containers and place
them into the garbage
once it has hardened.
Use a paper towel to
wipe and absorb
grease or oil on dishes
and pots before
washing them.
If you see a sewer overflow call
408.615.2000 immediately!
Grease was Removed From
Sewer Lines In Your Area!
Grease Management
Acceptable Specifications
for Grease Interceptors
All Grease Interceptors
(GIs) shall:
• Be approved by the International
Association of Plumbing and
Mechanical Officials (IAPMO)
per the Sanitary Use Ordinance.
• Be installed to manufacturer’s
specifications and comply
with current local, state, and
federal requirements.
• Be sized by the City of Santa
Clara (CSC)
• Be 500 gallons minimum
(California Plumbing
Code 1014.3.6) unless
authorized by CSC
• Include manholes over the
inlet, outlet, and baffle wall(s)
standpipes for purposes of
access, inspection, and cleaning.
• Include 24-inch diameter round
access covers.
• Include a 12-inch gap from
bottom floor of Grease
Interceptors to bottom
of standpipes.
• Include pre-test observation
by the CSC prior to
backfilling.
Grease in the system causes problems in storm drains and sanitary sewers — and increases your operating costs. •
Include connections to all
grease generating fixtures.
•
Include a sample box (see
reverse side for illustration).
The preferred type is a
minimum 5-gallon capacity
circular sample box and
is located immediately
downstream from the GI.
The sample box shall have
a hydraulic jump of
approximately six (6) inches or
a tee on the influent side
of the sample box (similar
to tee on influent side of GI).
Grease
Interceptor
Sample Box List of Grease
Interceptor vendors
• Jensen Precast
www.jensenprecast.com
(707) 429-5500
• Don Chapin Company
www.donchapin.com
(831) 449-4273
• US Concrete — Precast Group
www.us-concreteprecast.com
(925) 960-8740
• Greenturtle — Proceptor
www.greenturtletech.com
(877) 428-8187
• MC Nottingham
www.mcnottingham.com
(800) 834-9655
It is in no way to be implied or understood
that City of Santa Clara - Water and
Sewer Utilities Department endorses these
companies or their quality of work. This
list is provided as a courtesy and is only
a partial list of GI vendors in this area. It
is the responsibility of the person who is
hiring any of these companies to verify
their qualifications and references as well
as their compliance with regulations on
handling and transport of waste. This
sheet is intended for use in the City of
Santa Clara.
Serving the cities of San José, Santa Clara, and Milpitas, Cupertino Sanitary District, West Valley Sanitation District (including the cities of Campbell, Los Gatos, Monte Sereno, and Saratoga), County Sanitation District No. 2-3, and Burbank Sanitary District.
For more information:
City of Santa Clara
Water and Sewer Utilities
1500 Warburton Avenue
Santa Clara, CA 95050
408.615.2000
www.santaclaraca.gov
If you have any questions, please call 408.615.2000 to speak with a Code Enforcement Technician This and other outreach materials are available at www.santaclaraca.gov Measurement in inches
Grease Management
Grease Control Device Maintenance
Recordkeeping
Device: Grease Interceptor
Cleaning Method: Professional
Pumping Company Only
Establish and maintain a log to track
maintenance and hold receipts from your
professional pumping company. If you have
more than one grease interceptor, establish
and maintain a separate log for each one.
Receipts must include the following information:
• Pumping company name, address, and phone
number.
• Truck IKG number.
• Date and time of pumping service.
• Name and address of your business.
• Location of each grease control device.
• Size and type of your grease control device.
• Approximate quantity of grease and solid food
waste recorded in gallons, inches, or percentages.
• Pumping frequency.
• Details on any structural, maintenance, or repair
issues.
• Grease disposal location.
Grease in the system causes problems in storm drains and sanitary sewers — and increases your operating costs.
All food service establishments are required to keep
maintenance records for their grease traps, interceptors, and mechanical grease control devices for a minimum of three years.
Records must be readily available for review by Environmental Inspectors.
Grease
Interceptor/Trap
Maintenance
Log
Failure to maintain records on site for a minimum of three years is a violation of the local sewer ordinance and may result in fines.
Device: Grease Trap
Cleaning Method: Professional
Pumping Company or Self-Cleaning
Establish and maintain a log to track
maintenance and hold receipts from your
professional pumping company if you use
one. If you have more than one grease trap, establish
and maintain a separate log for each one.
Logs must include the following information:
• Date of cleaning.
• Name of person who cleaned the trap.
• Approximate quantity of grease and solid food
waste recorded in gallons, inches, or percentages.
• Location of each grease control device.
• Waste removal and disposal method.
• Grease disposal location.
• Any other relevant notes.
• Keep receipts with your self-cleaning log sheets if
you use a professional cleaning service.
Business: _______________ Grease Control Device Size: __________ Location of Grease Control Device: ______________________ Date of Name Waste Volume Maintenance Disposal Method Notes Cleaning Observed/Removed Done
07-07-11 John Smith 3-4 gallons Trap emptied, Solids dried, double-bagged, Patched hole FOG & solids removed cleaned put in dumpster. in baffle wall Example
Example of a Recordkeeping Log for a Grease Control Device Serving the cities of San José, Santa Clara, and Milpitas, Cupertino Sanitary District, West Valley Sanitation District (including the cities of Campbell, Monte Sereno, Saratoga, and the Town of Los Gatos), County Sanitation District No. 2-3, and Burbank Sanitary District.
For more information:
City of Santa Clara
Water and Sewer Utilities
1500 Warburton Avenue
Santa Clara, CA 95050
408.615.2000
www.santaclaraca.gov
If you have any questions, please call 408.615.2000 to speak with a Code Enfrocement Technician. This and other outreach materials, are available at www.santaclaraca.gov Whether you contract a professional pumping service,
perform the cleaning yourself, or do both, you are responsible for keeping and maintaining maintenance records.
Acme Cafe 100 lbs Underneath 3-pot sink
You must
keep a separate
log for each
grease
control device.
If you have any questions, please call 408.615.2000 to speak with a Code Enforcement Technician. This and other outreach materials are available at www.santaclaraca.gov 7-07-11 John Smith 3- 4 gallons Trap emptied, Solids dried, double-bagged, Patched hole FOG & solids removed cleaned put in dumpster. in baffle wall Business: ____________________ Grease Control Device Size: _____________________ Location of Grease Control Device: ____________________ Grease Control Device Maintenance Recordkeeping Log
Date of Waste Volume Maintenance
Cleaning Observed/Removed Done Name Disposal Method Notes If you have any questions, please call 408.615.2000 to speak with a Code Enfrocement Technician. This and other outreach materials are available at www.santaclaraca.gov Business: ____________________ Grease Control Device Size: _____________________ Location of Grease Control Device: ____________________ Grease Control Device Maintenance Recordkeeping Log
Date of Waste Volume Maintenance
Cleaning Observed/Removed Done Name Disposal Method Notes Grease Management
Grease Interceptor
Maintenance
What is the Purpose of
a Grease Interceptor?
• A grease interceptor is designed
to separate Fats, Oils, and Grease
(FOG) and solid food waste from
your kitchen wastewater.
• Buildup of FOG and solid
food waste in your plumbing
may cause blockages in either
your plumbing or the sanitary
sewer lines. This can lead to a
sanitary sewer overflow into your
building, a neighbor’s building,
streets, or the environment. It is
important to clean your grease
interceptor regularly.
Cleaning Frequency
• Grease interceptors shall be
cleaned at least once every
90 days. More frequent cleaning
may be necessary to keep your
interceptor operating properly.
Twenty-Five Percent Rule
• Pump your interceptor when
the final chamber is twentyfive percent (25%) full of FOG and solid food waste or within
90 days of the last pumping,
whichever comes first.
Grease in the system causes problems in storm drains and sanitary sewers — and increases your operating costs.
Standards for Evaluating
Grease Interceptors
• Manhole and sample box lids
should be easily removable
for cleaning and inspections.
• The baffle wall and all three
standpipes must be in place
and unbroken, above and below
the water and grease levels.
• If any standpipes are under
water or grease, they must be
raised above the grease level.
High water or grease level
could result from a blockage
in the downstream pipes.
• Downstream blockages could
indicate inadequate interceptor
cleaning frequency.
Grease
Interceptor
Kitchen Best Management Practices (BMPs)
• Grease and solid food waste can build up inside the interceptor and may cause the interceptor to operate less efficiently.
• Scraping grease and food waste to the garbage before washing dishes will minimize the amount of grease and solids going into the grease interceptor and will improve interceptor performance.
Tips on Routine Grease Interceptor Maintenance
• The pumping service should wash and scrape all sides, standpipes, and surfaces inside the interceptor and completely pump out all contents. • The pumping service shall not decant (return) wastewater back into the interceptor; the grease concentration in interceptor wastewater is very high. • Make sure your pumping service cleans the sample box and effluent standpipe of the interceptor. You may need to pump more often if you see fresh grease being discharged into your sample box.
• Require the pumping service to show the disposal destination for your waste on the pumping invoice. Your business may be liable for any illegal dumping or discharge of waste from your facility.
• Do visual inspections after pumping services are performed or when plumbers snake or hydro-jet plumbing or laterals to make sure the interceptor standpipes are not damaged.
• Keep grease interceptor pumping records on site for a minimum of three years. Refer to the Grease Control Device Maintenance Recordkeeping sheet for more information.
Failure to maintain records on site for a minimum of three years is a violation of your local sewer ordinance and may result in fines. See the “Grease Control Device Maintenance Recordkeeping” factsheet for more information.
Serving the cities of San José, Santa Clara, and Milpitas, Cupertino Sanitary District, West Valley Sanitation District (including the cities of Campbell, Monte Sereno, Saratoga and the Town of Los Gatos), County Sanitation District No. 2-3, and Burbank Sanitary District.
For more information:
City of Santa Clara
Water and Sewer Utilities
1500 Warburton Avenue
Santa Clara, CA 95050
408.615.2000
www.santaclaraca.gov
If you have any questions, please call 408.615.2000 to speak with a Code Enforcement Technician. This and other outreach materials are available at www.santaclaraca.gov Discharging anything,
including oil, grease
waste, wash water, or
rinse water to the
storm drain system
is a violation of the local
sewer use ordinance.
Discharging used cooking
or deep fryer oil, rotisserie
fat, or solid food waste
into kitchen sinks, mop
sinks, and floor drains in
your kitchen that are
connected to the
sanitary sewer system
is a violation of your local
sewer use ordinances.
Grease Management
Your Grease
Trap may
look different.
Grease Trap
Maintenance
What is the Purpose
of a Grease Trap?
• A grease trap is designed to
separate Fats, Oils, and Grease
(FOG) and solid food waste
from your kitchen wastewater.
• Buildup of FOG and solid
food waste in your plumbing
may cause blockages in either
your plumbing or the sanitary
sewer lines. This can lead to an
overflow into your building, a
neighbor’s building, streets, or
the environment. It is important
to clean your grease trapregularly.
Cleaning Frequency
• Grease traps shall be cleaned at
least once every 30 days. More
frequent cleaning may be
necessary if:
• Your sinks are draining slowly,
possibly due to buildups in the trap.
• Waterlevels in the traporfloordrains
are high,possiblydue to grease-related
blockages in yourplumbing.
• The grease trap smells bad because
solids are filling the bottom of the
trap quickly.
• Your trap is not sized correctly for
your restaurant operations, menu,
or number of meals served.
Twenty-Five Percent Rule
• Clean the trap when it is twentyfive percent (25%) full of FOG and solid food waste or within
30 days of the last pumping,
whichever comes first.
Grease in the system causes problems in storm drains and sanitary sewers — and increases your operating costs.
Common Problems
Leading to Grease Trap
Repair or Replacement
• Grease trap installed
backwards, without flow
controls, or otherwise in
violation of plumbing codes or
manufacturer specifications.
• Missing or damaged parts,
such as the removable
baffle plates.
• Leaksdue to rust holes or
punctures in the walls orfloors.
• Illegal connection to the
dishwasher or garbage grinder
to the grease trap.
Grease Trap
Kitchen Best Management Practices (BMPs)
• Scraping grease and food waste to the garbage before washing dishes will minimize the amount of grease and solids going into the grease trap and will often improve trap performance.
Tips on Routine Grease Trap Maintenance
• To ensure proper maintenance, we recommend using a professional grease hauling company.
• Cleaning consists of emptying the entire trap, including FOG, wastewater, and solid food waste; making sure the removable baffle plates and parts are thoroughly cleaned and replaced properly after each cleaning.
• Keep a maintenance log sheet posted near the grease trap if you self-clean the trap.
• Melt ice in the sink plumbed to the grease trap an hour or two before cleaning. This helps cool and harden the grease in the trap, making cleaning easier and reducing odors.
• Have an extra gasket available for your grease trap lid and use allen screws (which resist stripping) to secure the lid.
• Run your hood fans during cleaning to reduce odors.
• Call a plumber to snake or hydro-flush your sewer lateral (plumbing) pipes to the street periodically to remove any blockages. • If you choose to self-clean your grease trap, please see the "How to Clean Your Grease Trap" poster for guidance.
Dishwasher or
garbage grinder
waste must
NOT flow to
the trap!
Failure to maintain records on site for a minimum of three years is a violation of your local sewer ordinance and may result in fines. See the “Grease Control Device Maintenance Recordkeeping” factsheet for more information.
Serving the cities of San José, Santa Clara, and Milpitas, Cupertino Sanitary District, West Valley Sanitation District (including the cities of Campbell, Monte Sereno, Saratoga and the Town of Los Gatos), County Sanitation District No. 2-3, and Burbank Sanitary District.
For more information:
City of Santa Clara
Water and Sewer Utilities
1500 Warburton Avenue
Santa Clara, CA 95050
408.615.2000
www.santaclaraca.gov
If you have any questions, please call 408.615.2000 to speak with a Code Enforcement Technician. This and other outreach materials are available at www.santaclaraca.gov Discharging anything,
including oil, grease
waste, wash water, or
rinse water to the
storm drain system
is a violation of the local
sewer use ordinance.
Discharging used cooking
or deep fryer oil, rotisserie
fat, or solid food waste
into kitchen sinks, mop
sinks, and floor drains in
your kitchen that are
connected to the
sanitary sewer system
is a violation of your local
sewer use ordinances.
Printed on recycled paper. 0316/200/EGAD/JV
408.615.2000
www.santaclaraca.gov
Scoop top grease
Saque la grasa acumulada en la parte
superior con una pala / Vớt váng dầu
Scoop out water. Leave solids and sludge behind.
Pour water into a sanitary sewer (indoor) drain.
Let grease trap cool down. Scoop out oil and grease.
Place waste in a plastic bag.
Scrape waste from all sides and bottom of the
grease trap. Place in a plastic bag.
Check and clean all removable parts, baffles,
and/or screens. Place waste in a plastic bag.
Securely tie up bags of waste. Dispose in a trash can
or dumpster. Close lid over trash.
Pour cat litter into bag(s) of waste
and mix until dry. Double-bag the
waste.
Reassemble trap. Tighten lid. Record cleaning on
maintenance log sheet.
Remove water
Saque el agua
Đổ nước đi
Remove solids and sludge
Remueva los sólidos y residuos
Đổ đi chất rắn và bùn
Clean all parts
Limpie todas las partes
Làm sạch các bộ phận
Make waste solid
Solidifique los desechos
Làm đặc
Dispose
Deseche
Vứt bỏ
Reassemble and record
Vuelva a ensamblar, rellene y registre
Lắp ráp lại và ghi chép
CÁCH THỨC LÀM
SẠCH BẪY DẦU
MỠ CỦA BẠN
Giữ dầu mỡ ra khỏi cống rãnh bằng cách
làm theo các bước đơn giản này:
Hãy để cho cái bẫy nguội. Vớt ra phần dầu và mỡ
nổi trên mặt. Bỏ vào túi nhựa.
Bỏ cát mèo (cat litter) vào trong các
túi nhựa chất thải rồi trộn cho đến
khi khô. Để túi vào trong một túi
nhựa khác.
Cột chặt túi lại. Bỏ vào thùng rác. Đậy nắp thùng rác.
Ráp lại cái bẫy. Đậy nắp cho chặt. Ghi vào hồ sơ bảo
trì mọi chi tiết làm sạch bẩy dầu mỡ.
Múc nước ra. Chừa lại chất rắn và bùn. Đổ nước
xuống hệ thống cống thoát nước vệ sinh (trong nhà).
Cạo ra chất thải ở mặt trên, mặt dưới và xung quanh
của cái bẫy dầu mỡ. Bỏ hết chất thải vào túi nhựa.
Kiểm tra và làm sạch các bộ phận rời, vách ngăn,
và/hoặc màn lưới. Bỏ hết chất thải vào túi nhựa.
Saque el agua de la trampa. Deje detrás los sólidos
y residuos. Tire el agua en un drenaje sanitario.
Deje que se enfríe la trampa de grasa. Saque el
aceite y grasa y pongala en una bolsa de plastico.
Raspe los sólidos y residuos de las superficies de
las paredes y del fondo de la grasa y pongala en
una bolsa de plastico.
Inspeccione y limpie las partes y/o pantallas y
pongala en una bolsa de plastico.
Ate las bolsas de residuos de manera segura.
Deshágase de las bolsas en un basurero o
contenedor de basura. Cierre la tapa sobre la basura.
Vierta arena para gatos en las bolsas
con la grasa y residuos, y mezcle
hasta que la grasa se solidifique o
hasta que la grasa se seque.
Después ponga los residuos con la
arena de gato en bolsa doble.
Vuelva a ensamblar la trampa, apriete la tapa y
anote en la hoja de registro de mantenimiento.
COMPLIANCE WARNING: You are required by your sewer use ordinance to keep the grease trap in efficient operating condition. Failure to do so can result in fines or other penalties.
Keep grease out of the sanitary
sewer by following these simple steps:
HOW TO
CLEAN YOUR
GREASE TRAP
CÓMO LIMPIAR
LAS TRAMPAS
DE GRASA
ADVERTENCIA: Usted esta obligado por la ordenanza del uso del alcantarillado sanitario a mantener la trampa de grasa operando en condiciones eficientes. Falta de mantener la trampa de grasa en condición eficiente puede resultar en multas o otros penales.
KHUYẾN CÁO: Về việc phải tuân giữ hợp lê. Luật lệ về việc bảo trì cái bẫy dầu mỡ đòi hỏi bạn luôn luôn giữ gìn cái bẫy dầu mỡ trong điều kiện tốt và điều hành hiệu quả. Mọi khiếm khuyết trong việc tuân hành luật lệ này có thể đem lại việc bị phạt tiền và các hình phạt khác. ¡Mantenga la grasa fuera del alcantarillado,
y proteja nuestros arroyos y la Bahía
siguiendo estos pasos sencillos:
1 2
3 4
7 6
5 !
Tributary agencies served by the treatment plant: San José, Santa Clara, Milpitas, Cupertino Sanitary District, West Valley Sanitation District (including Campbell, Los Gatos, Monte Sereno, Saratoga), County Sanitation Districts 2-3, Burbank Sanitary District.
Hello,
I am a Code Enforcement Technician with the City of Santa Clara. I am here to perform an inspection of your business. Santa Clara conducts inspections of restaurants, cafetereias, and other food service operations. We inspect these businesses to ensure that they are:
1. In compliance with environmental laws, and
2. Not releasing excessive grease into the sanitary sewer that can cause sanitary sewer blockages, backups, and overflows.
The inspection will consist of asking you questions about your business activities, walking through your business site, and reviewing certain records. We will also provide you with educational materials and information that can help your business stay in compliance with water pollution laws and protect the environment.
We appreciate the opportunity to work with you to protect the sanitary sewer system and minimize pollution of our local creeks, rivers, and the Bay. For additional information on this inspection and ways you can help us protect our local waterways, please visit our website www.santaclaraca.gov or call our office at 408.615.2000
Grease Management
Prohibitions on using
Chemicals, Enzymes, or Bacteria
in Grease Traps and Interceptors
Grease in the system causes problems in storm drains and sanitary sewers — and increases your operating costs.
Chemicals: the use
of chemicals to
clean grease traps
or interceptors is
strictly prohibited
because:
• Local sewer use ordinances
prohibit the use of chemicals as
a method to remove grease from
your grease trap or interceptor.
• Cleaners, solvents, caustics,
or other chemicals cannot be
used to dissolve accumulated
grease from your grease trap
or grease interceptor. These
chemicals cause grease to flow
out of your trap or interceptor
in violation of local ordinances.
The grease may deposit on
sewer pipes downstream of your
business, obstructing them and
contributing to sewer overflows.
Enzymes: the use
of enzymes to
clean grease traps
or interceptors is
strictly prohibited
because:
• Whether produced synthetically
or from animals, enzymes cannot
be used to dissolve grease from
your grease trap or interceptor.
• Enzymes can temporarily
alter the chemical form of the
grease, allowing it to dissolve
into the water. However, the
altered grease may reform into
solid matter downstream from
your business, obstructing
sewer pipes.
Bacteria: the use
of bacteria to
clean grease traps
or interceptors is
strictly prohibited
because:
• Bacteria need a reliable
environment to grow and
are sensitive to changes in
temperature, pH, oil and
grease loading, water flow
changes, etc. It is difficult
to maintain the conditions
necessary for bacteria to thrive
in a kitchen environment.
Biological expertise and ongoing
sampling are often needed for
bacteria to be sustainable.
• Even if bacteria survive and
flourish, their effectiveness in
removing grease is limited.
“Partially eaten” (i.e., not broken
down completely) grease may
still enter the plumbing and over
time reform into solid matter
downstream, obstructing the
sewer pipes.
CHEMICALS ENZYMES BACTERIA
Serving the cities of San José, Santa Clara, and Milpitas, Cupertino Sanitary District, West Valley Sanitation District (including the cities of Campbell, Los Gatos, Monte Sereno, and Saratoga), County Sanitation District No. 2-3, and Burbank Sanitary District.
If you have any questions, please call 408.615.2000 to speak with a Code Enforcement Technician.
This and other outreach materials are available at santaclaraca.gov For more information:
City of Santa Clara
Water and Sewer Utilities
1500 Warburton Avenue
Santa Clara, CA 95050
408.615.2000
www.santaclaraca.gov
Per the sewer use ordinance:
“No person shall
discharge…any
substance of any kind
whatsoever tending
to obstruct or injure
the sanitary sewer
system, or to cause a
nuisance or hazard,
or which will in any
manner interfere with
the proper operation or
maintenance of the
sanitary sewer system.”
In general…
• Greasy wastewater may not be discharged to the sanitary sewer system unless it has been treated using a grease trap or interceptor approved by the Environmental Services Department.
• Floating or solid grease matter must be physically removed from your grease removal device by pumping, scraping, scooping, etc. • Maintain your grease trap and interceptor in efficient operating condition by regular removal of accumulated grease.
• The minimum cleaning frequency required for grease interceptors installed in food service facilities is once every 90 days. However, more frequent cleaning may be necessary.
• The minimum cleaning frequency required for grease traps installed in food service facilities is once every 30 days. However, more frequent cleaning may be necessary.
Grease Management
Proper Cleaning and Rinse
Water Disposal for Exhaust Hoods,
Filters, Ducting, Roof Fans, and Floor Mats
Cleaning Exhaust Hoods
and Exhaust Hood Filters
On Site
• Dry-wipe and scrape grease off of
all surfaces before washing.
• Empty and clean the grease
collection trays located inside of
the exhaust hoods regularly.
Cleaning Exhaust
Hood Filters Off Site
• The business owner may choose
to use professional services to
exchange dirty exhaust hood
filters for clean ones.
Cleaning Frequency
• Check your lease agreements and
fire insurance policies to determine
the minimum frequency that you
must clean your equipment.
• More frequent cleaning may be
necessary if grease collects quickly.
Grease in the system causes problems in storm drains and sanitary sewers — and increases your operating costs.
Cleaning Exhaust
Ducting and Rooftop
Exhaust Fans
• Do not allow wash and rinse
water to go into downspouts.
• Do not leave pooled wash and
rinse water on the roof.
• Collect the wash and rinse
water and discharge to the
sanitary sewer drains inside
your business.
Whether you contract with
a professional service,
perform the cleaning yourself,
or do both, you are liable
for any illegal disposal
of waste or rinse water
resulting from cleaning
your exhaust hood, filters,
ducting, and roof fans. This
includes any cleaning that
occurs off site.
Never clean exhaust hoods
or filters outdoors where
wash water may flow to a
storm drain.
Proper Disposal of Filter Bath Solution
• Used bath solution from soaking exhaust hood filters (both hazardous and non-hazardous) should be taken to an off-site disposal facility. You and your property manager are liable for any illegal disposal of your waste.
Proper Disposal of Water from Equipment Cleaning
• Do not dispose of the concentrated solution, wash water, or rinse water from cleaning or degreasing equipment or exhaust hood surfaces into sinks leading to a grease trap or mechanical grease removal device. • Do dispose of the concentrated solution, wash water, or rinse water into a mop-sink, sink, or floor drain connected directly to the sanitary sewer system.
• Do dispose of wastewater from steam cleaning without chemicals to a grease trap or mechanical grease removal device.
• Do not pour concentrated chemicals into sinks, mop sinks, or floor drains plumbed to grease control devices. This may cause liquefied grease to escape the grease control device and could cause a blockage in your drainage system.
Proper Disposal of Water from Cleaning Floor Mats
Wash water from cleaning floor mats must never flow out the back door, onto the parking lots, into a gutter, or into a storm drain. Clean mats:
• In a mop sink or near a floor drain, or
• Outside in a designated area that flows to a sanitary sewer drain, or • In a garbage can; then dispose of the wash water into a mop sink.
Discharging anything,
including oil, grease
waste, wash water, or
rinse water to the
storm drain system
is a violation of the local
sewer use ordinance.
Serving the cities of San José, Santa Clara, and Milpitas, Cupertino Sanitary District, West Valley Sanitation District (including the cities of Campbell, Los Gatos, Monte Sereno, and Saratoga), County Sanitation District No. 2-3, and Burbank Sanitary District.
For more information:
City of Santa Clara
Water and Sewer Utilities
1500 Warburton Ave
Santa Clara, CA 95050
408.615.2000
www.santaclaraca.gov
If you have any questions, please call 408.615.2000 to speak with a Code Enfrocement Technician.
This and other outreach materials, are available at santaclaraca.gov Discharging used cooking
or deep fryer oil, rotisserie
fat, or solid food waste
into kitchen sinks, mop
sinks, and floor drains in
your kitchen that are
connected to the
sanitary sewer system
is a violation of your local
sewer use ordinances.
Do it Right Hágalo bien Lam Cho Ñuùngø
WASTE ÁREA DE
STORAGE CONFINAMIENTO
AREA DE RESIDUOS
Compactors / Dumpsters / Tallow Bins Compactadores / Contenedores / Recipientes de sebo Maintain and clean waste enclosure area
on a regular basis.
Mantenga limpias las áreas de confinamiento de
residuos regularmente.
Thöôøng xuyeân giöõ gìn veä sinh chung quanh choã
ñeå raùc.
Do not hose down dumpsters,
compactors, tallow bins, or the enclosure
area to the storm drain.
No lave con manguera los contenedores, los
compactadores, recipientes de cebo o el área de
residuos al desagüe pluvial.
Khoâng ñöôïc xòt nöôùc ñeå röûa caùc thuøng ñöïng raùc, caùc maùy neùn raùc, caùc thuøng ñöïng daàu môõ, hoaëc
khu vöïc bao quanh xuoáng coáng thoaùt nöôùc möa.
When you clean the enclosure, collect all
wash water and dispose of it in the
sanitary sewer.
Cuando limpie el área de confinamiento de residuos
recoja toda el agua sucia y dispóngala en el alcantarillado sanitario.
Khi doïn saïch khu vöïc ñoå raùc, thu laïi nöôùc röûa vaø ñoå vaøo oáng coáng veä sinh.
Do not put liquid waste in dumpster
or compactor.
No ponga residuos líquidos en el contenedor o
en el compactador.
Khoâng ñoå chaát thaûi öôùt vaøo thuøng ñöïng
raùc lôùn hoaëc maùy neùn raùc.
Train employees to keep waste enclosure
area clean and prevent all wash water
from going to the storm drain.
Entrene a los empleados para mantener limpia el
área de residuos y evitar que el agua sucia vaya a
los desagües pluviales.
Huaán luyeän nhaân vieân veà vieäc giöõ cho khu
vöïc bao quanh choã ñeå raùc ñöôïc saïch seõ, vaø giöõ cho nöôùc röûa khoâng chaûy vaøo coáng thoaùt nöôùc möa.
Prevent spills and leaks, and have spill kit
readily available for clean up.
Prevenga los derrames y fugas y tenga listo un kit de
limpieza de derrames.
Phoøng ngöøa chaát pheá thaûi ñoå ra, vaø chuaån bò saün duïng cuï ñeå lau doïn.
Clean up all spills and leaks immediately
using spill kit. Sweep up absorbent right
away; do not let it sit out overnight or in
the rain.
Limpie todos los derrames y fugas inmediatamente
usando el kit para derrames. Barra enseguida el
absorbente, no lo deje de un día para otro o para
cuando llueve.
Lau doïn ngay taát caû caùc choã ñoå thaùo baèng duïng
cuï ñeå lau doïn. Queùt doïn ngay chaát thaám; khoâng
ñeå chaát naøy beân ngoaøi qua ñeâm hoaëc döôùi möa.
Close lids on all containers after use.
Cierre las tapas de todos los contenedores
después de su uso.
Ñoùng naép ñaäy cho taát caû caùc thuøng ñöïng
sau khi duøng.
Double-bag wet waste. Mix dry
absorbent in with wet waste, then tie off
bags. Use buckets to transfer bagged wet
waste to the dumpster.
Ponga los residuos líquidos en doble bolsa.
Mézclelos con material absorbente, luego amarre las
bolsas. Utilice baldes para pasar la bolsa de residuos
líquidos al contenedor.
Duøng hai bao raùc loàng vaøo nhau ñeå ñöïng raùc öôùt. Troän chaát thaám nöôùc vôùi raùc öôùt, vaø coät bao laïi. Duøng soâ ñöïng ñeå chuyeån bao raùc öôùt tôùi thuøng ñöïng raùc.
Call your hauler to replace leaky bins
immediately.
Llame a su transportista para reemplazar los
contenedores con fugas inmediatamente.
Goïi coâng ty keùo raùc ñeán thay ngay caùc
thuøng ñöïng raùc ñaõ bò thuûng.
Keep your waste storage area clean to protect the Bay
Mantenga limpia el área de confinamiento de residuos para proteger la bahía 408.615.2000
www.santaclaraca.gov
* Failure to be in compliance may subject your business to an Administrative Citation with a fine of $500 or more. *La falta de cumplimiento puede causarle a su negocio una medida administrativa con multa hasta de $500 ó más.
Appendix J
City of Santa Clara Sewer Capacity
Assessment
Water and Environment
May 2007
City of Santa Clara
Sanitary Sewer Capacity
Assessment
FINAL REPORT
Prepared by:
Appendix J
May 31, 2007
Mr. Rajeev Batra
City Engineer
City of Santa Clara Engineering Department
1500 Warburton Avenue
Santa Clara, CA 95050
Subject: Sanitary Sewer Capacity Assessment
Dear Mr. Batra:
RMC Water and Environment is pleased to submit this Final Report on the Sanitary Sewer Capacity Assessment for the City of Santa Clara. The report reflects the collaborative efforts of the RMC team and dedicated staff of the City’s Public Works Engineering Department and Water and Sewer Utilities to prepare a comprehensive assessment of the capacity needs of the City’s trunk sewer system.
The Capacity Assessment has been based on a detailed study methodology encompassing use of sewer flow monitoring, water use, and land use planning data, coupled with stateof-the-art hydraulic modeling, to identify the future capacity requirements of the City’s sanitary sewer system and develop recommended capacity improvement projects. The study also complies with Regional and State regulatory requirements for all collection system agencies to prepare Sewer System Management Plans addressing the operation, maintenance, and management of their systems.
The Capacity Assessment report identifies nine capacity improvement projects in the trunk sewer system, totaling about $20 million in capital costs, that will enable the City to maintain its high level of service to the community and provide adequate capacity to serve proposed future development and redevelopment. The report also includes recommendations and guidelines for implementing the recommended capital improvement program and continuing to track the flows and capacity of the system. The hydraulic model of the trunk sewer system developed for this study will allow the City to update the capacity assessment as changes occur over time.
We appreciate the opportunity to have worked with the City on this very challenging project. We would like to thank you for your oversight and direction of this effort, for the guidance and dedication of the City’s Project Manager, Falguni Amin, and for the input and assistance provided by many other City staff members on this Capacity Assessment project.
Sincerely,
Gisa Ju, P.E. Tammy Qualls, P.E.
Project Manager Project Engineer
City of Santa Clara
Sanitary Sewer Capacity Assessment
Final Report
Prepared by:
Water andEnvironment
May 2007
(This page intentionally left blank)
City of Santa Clara Sanitary Sewer Capacity Assessment Table of Contents May 2007 i
Table of Contents
Executive Summary..............................................................................................................ES-1 Chapter 1 Introduction ...........................................................................................................1-1
1.1 Background and Study Objectives ..........................................................................1-1
1.2 Wastewater Collection System ...............................................................................1-1
1.3 Scope of Study........................................................................................................1-1
1.4 Report Organization................................................................................................1-5 Chapter 2 Land Use and Flow Estimates .............................................................................2-1
2.1 Land Use Projections..............................................................................................2-1
2.1.1 Planning Scenarios .................................................................................................2-1
2.2 Flow Monitoring Program........................................................................................2-4
2.3 Wastewater Flows...................................................................................................2-7
2.3.1 Wastewater Flow Components ...............................................................................2-7
2.3.2 Methods for Estimating Base Wastewater Flows....................................................2-8
2.3.3 Diurnal Base Wastewater Flow Patterns.................................................................2-9
2.3.4 Large Users...........................................................................................................2-11
2.3.5 Infiltration/Inflow ....................................................................................................2-12
2.3.6 Design Event.........................................................................................................2-13
2.3.7 Flows from Cupertino Sanitary District..................................................................2-14
2.3.8 Wastewater Flow Estimates..................................................................................2-15 Chapter 3 Hydraulic Model Development.............................................................................3-1
3.1 Modeled System .....................................................................................................3-1
3.2 Model Network Construction and Validation ...........................................................3-1
3.3 Development of Model Loads .................................................................................3-3
3.3.1 Base Wastewater Loads .........................................................................................3-3
3.3.2 I/I Loads ..................................................................................................................3-3
3.4 Model Calibration ....................................................................................................3-6
3.4.1 Dry Weather Calibration..........................................................................................3-6
3.4.2 Wet Weather Calibration.........................................................................................3-9 Chapter 4 Capacity Analysis .................................................................................................4-1
4.1 Hydraulic Analysis and Design Criteria ...................................................................4-1
4.2 Capacity Analysis Results.......................................................................................4-2
4.2.1 Cupertino Sanitary District Flows............................................................................4-2
4.3 Preliminary Solutions to Capacity Deficiencies.......................................................4-5 Chapter 5 Capacity Improvement Projects ..........................................................................5-1
5.1 Potential Flow Diversion Alternatives......................................................................5-1
5.2 Potential Diversions to New Sewers .......................................................................5-2
5.3 Construction Considerations...................................................................................5-2
5.4 Capacity Relief Projects..........................................................................................5-3
5.4.1 Projects 1 and 2 – Bowers Ave, Mission College Blvd and Great America Pkwy...5-3
5.4.2 New West-to-East Trunk Sewer Alternative............................................................5-5
5.4.3 Projects 4A and 4B – Machado Avenue and Chromite Drive .................................5-6
5.4.4 Project 5 – Monroe Street .......................................................................................5-6
5.4.5 Project 6 – Nobili Avenue and Machado Avenue....................................................5-6
5.4.6 ECR Diversion to Calabazas Trunk Sewer .............................................................5-6 City of Santa Clara Sanitary Sewer Capacity Assessment Table of Contents May 2007 ii
5.4.7 Project 8 – El Camino Real.....................................................................................5-7
5.4.8 Project 9 – Scott Boulevard.....................................................................................5-7
5.4.9 Project 10 – Park Avenue .......................................................................................5-7 Chapter 6 Recommended Capital Improvement Program ..................................................6-1
6.1 Estimated Cost of Proposed Sewer Improvement Projects ....................................6-1
6.2 Comparison of Major Alternatives ...........................................................................6-3
6.3 Prioritization and Schedule for Proposed CIP Projects...........................................6-3
6.4 Implementation Recommendations.........................................................................6-5 List of Tables
Table ES-1 Sewer System Flow Estimates ............................................................................ES-6 Table ES-2 Recommended Capacity Improvement Projects..................................................ES-9 Table ES-3 Project Costs and Priority Groups......................................................................ES-10 Table 2-1 Planned Development/Redevelopment .....................................................................2-2 Table 2-2 Planned Development Summary ...............................................................................2-4 Table 2-3 Flow Monitoring Locations .........................................................................................2-5 Table 2-4 Rain Events during Flow Monitoring Period...............................................................2-7 Table 2-5 Base Wastewater Flow Unit Flow Factors .................................................................2-9 Table 2-6 Large Dischargers ...................................................................................................2-11 Table 2-7 Sewer System Flow Estimates ................................................................................2-15 Table 3-1 Comparison of Meter and Model Flow.......................................................................3-6 Table 3-2 GWI and RDI/I Parameters by Meter Area ..............................................................3-11 Table 4-1 Hydraulic Design Criteria ...........................................................................................4-1 Table 4-2 Capacity Deficiencies and Preliminary Solutions.......................................................4-6 Table 5-1 Recommended Capacity Improvement Projects .......................................................5-3 Table 6-1 Summary of Cost Criteria ..........................................................................................6-2 Table 6-2 Estimated Costs of Capacity Improvement Projects..................................................6-2 Table 6-3 Project Priority Groups...............................................................................................6-4 City of Santa Clara Sanitary Sewer Capacity Assessment Table of Contents May 2007 iii
List of Figures
Figure ES-1 Sewer System.....................................................................................................ES-2 Figure ES-2 Modeled System .................................................................................................ES-4 Figure ES-3 Planned Development/Redevelopment ..............................................................ES-5 Figure ES-4 Predicted Capacity Deficiencies .........................................................................ES-7 Figure ES-5 Recommended Capacity Improvement Projects ................................................ES-8 Figure ES-6 Proposed CIP Schedule ...................................................................................ES-11 Figure 1-1 Study area ................................................................................................................1-2 Figure 1-2 Sewer System ..........................................................................................................1-3 Figure 2-1 Planned Development/Redevelopment ....................................................................2-3 Figure 2-2 Flow Meter Sites.......................................................................................................2-6 Figure 2-3 Wastewater Flow Components.................................................................................2-8 Figure 2-4 Diurnal Curves........................................................................................................2-10 Figure 2-5 RDI/I Hydrograph Components ..............................................................................2-13 Figure 2-6 10-Year Design Storm for San Jose Airport ...........................................................2-14 Figure 3-1 Modeled System.......................................................................................................3-2 Figure 3-2 Subbasins and Load Manholes ................................................................................3-4 Figure 3-3 Flow Meter Areas Used for I/I Analysis ....................................................................3-5 Figure 3-4 Meter Schematic.......................................................................................................3-7 Figure 3-5 Example Dry Weather Calibration Plots ...................................................................3-8 Figure 3-6 Example Wet Weather Calibration Plots ................................................................3-10 Figure 4-1 Model Results – Future PDWF.................................................................................4-3 Figure 4-2 Model Results – Future PWWF ................................................................................4-4 Figure 4-3 Preliminary Capacity Improvements.........................................................................4-7 Figure 5-1 Recommended Capacity Improvement Projects ......................................................5-4 Figure 6-1 Proposed CIP Schedule ...........................................................................................6-5 Appendices
Appendix A - Plots of Flow Monitoring Data
Appendix B - Project Descriptions and Cost Estimates
City of Santa Clara Sanitary Sewer Capacity Assessment Table of Contents May 2007 iv
Acknowledgements
City of Santa Clara
Rajeev Batra, City Engineer
Tom Supan, Principal Engineer
Falguni Amin, Project Manager
Gustavo Gomez, Principal Engineer
Jim Parissenti, Principal Engineer
Kimchi Tran, Civil Engineer I
Robin Saunders, Director of Water and Sewer Utilities
Alan Kurotori, Assistant Director Sewer Utility
Kevin Riley, Director of Planning and Inspection
Doug Handerson, Associate Planner
RMC Water and Environment
Steve Bui, Principal-in-Charge
Gisa Ju, Project Manager
Tammy Qualls, Project Engineer
Carrie Teng
Catherine Greenman
Glenn Hermanson
E2 Consulting Engineers, Flow Monitoring
City of Santa Clara Sanitary Sewer Capacity Assessment Table of Contents May 2007 v
List of Abbreviations and Definitions
ADWF Average dry weather flow: the average flow during dry (non-rainfall) periods APN Assessor parcel number
CIP Capital Improvement Program
City City of Santa Clara
CSJ City of San Jose
CuSD Cupertino Sanitary District
d/D Ratio of flow depth to pipe diameter
DU Dwelling unit
DWF Dry weather flow: the flow during non-rainfall periods, composed of normal sanitary flow contributions from residential, commercial, institutional, and industrial users of a sewer system plus any dry season groundwater infiltration.
E2 E2 Consulting Engineers, Inc.
ECR El Camino Real
ENR-CCI Engineering News Record Construction Cost Index: an index published monthly by Engineering News Record magazine and used to reference construction costs (such as those for wastewater system facilities) to a specific date and location.
FAR Floor-area-ratio: the ratio of building floor space to total parcel area GIS Geographic Information System: a computerized system in which geographical features (e.g., sewer facilities, parcels, land use) are linked to an attribute database to facilitate analysis and presentation of information. gpad or gpd/ac Gallons per day per acre
gpcd Gallons per capita per day
gpd Gallons per day
gpm Gallons per minute
GWI Groundwater infiltration: extraneous water that infiltrates a sewer system from the ground through defective pipes and manholes. Groundwater is considered to be a relatively constant daily flow that varies seasonally and depends on location of sewers with respect to the groundwater table.
City of Santa Clara Sanitary Sewer Capacity Assessment Table of Contents May 2007 vi
IDF Intensity-duration-frequency: rainfall statistics that establish the rainfall intensity over specified durations for various recurrence frequencies I/I Infiltration/inflow: extraneous groundwater and/or storm water that enter a sanitary sewer system.
K Recession coefficient of RDI/I unit hydrograph
lf Linear feet
mgd Million gallons per day
PDWF Peak dry weather flow: the peak flow during non-rainfall periods PS Pump Station
PWWF Peak wet weather flow: the peak flow during a given storm event from dry weather flow plus infiltration and inflow.
R Ratio of RDI/I volume to rainfall volume
R&D Research and Development
RDI/I Rainfall-dependent infiltration/inflow: the infiltration and inflow into a sewer system directly related to a rainfall event. RDI/I may cause rapid, short-term peak flows in the sewer system that recede after the rainfall has ended.
RG Rain gauge
Regional Board Regional Water Quality Control Board: a division of the State Water Resources Control Board that administers wastewater discharge permits in a specific region of California. The City of Santa Clara falls under the jurisdiction of the San Francisco Bay Regional Board.
RMC RMC Water and Environment
SJ/SC WPCP San Jose/Santa Clara Water Pollution Control Plant SSMP Sewer System Management Plan
State Board State Water Resources Control Board
Surcharge The hydraulic condition in a sewer pipeline in which the elevation of the hydraulic gradeline (water level) is above the crown (top) of the pipe. Under such a condition, the water in the pipe rises into the manholes and could overflow onto the ground if the hydraulic gradeline exceeds the elevation of the manhole rims.
T Time to peak of RDI/I unit hydrograph
Executive Summary
City of Santa Clara Sanitary Sewer Capacity Assessment Executive Summary May 2007 ES-1
Executive Summary
This report summarizes the results and recommendations of the Sanitary Sewer System Capacity Assessment for the City of Santa Clara (City). The Capacity Assessment was prepared by RMC Water and Environment (RMC) in close coordination with City staff. The Capacity Assessment will be used to guide improvements to the City’s sanitary sewer system to accommodate current and future development to ensure that the City continues to maintain a high level of service to its customers.
Background and Purpose of Capacity Assessment
The City of Santa Clara is located in central Santa Clara County adjacent to the Cities of San Jose, Cupertino, and Sunnyvale. The City has a population of approximately 110,000 and is served by a wastewater collection system consisting of approximately 270 miles of sewer pipelines and six sewage pump stations. The collection system conveys wastewater flows to the San Jose/Santa Clara Water Pollution Control Plant (SJ/SC WPCP), located north of Highway 237 in San Jose. The City also receives flow from the Cupertino Sanitary District (CuSD) at Homestead Road under an agreement with the City executed in 1985. The City’s sewer system and service area are shown in Figure ES-1.
The City is experiencing significant growth and redevelopment, necessitating an evaluation of the capacity of the sanitary sewer system to handle future wastewater flows. This evaluation will help identify future capital needs for capacity improvements and associated requirements for financing those improvements through increased connection fees or other sources of funding.
Furthermore, the City is also required to complete a capacity evaluation and capacity assurance plan as part of preparing its Sewer System Management Plan (SSMP). The SSMP addresses the overall management, operation, and maintenance of the sanitary sewer system and is required for all sewer system agencies by the Regional Water Quality Control Board, as well as under the Statewide General Waste Discharge Requirements adopted in 2006 by the State Water Resources Control Board.
The overall objectives of this Capacity Assessment study are to develop wastewater flow projections for the City’s collection area using up-to-date water use and land use information; develop a hydraulic model of the trunk sewer system; use the model to identify capacity deficiencies in the existing system and future capacity requirements; and develop a phased Capital Improvement Program, including budget estimates, for implementing the required capacity improvements to the sanitary sewer system.
This Executive Summary is presented in two parts:
▪ How the Capacity Assessment was Prepared describes the scope and methodologies of the planning effort, including the key planning and technical assumptions incorporated into the sewer system capacity analysis.
▪ Recommended Capacity Improvement Program presents the recommended Capital Improvement Program (CIP), including capacity improvement projects, priorities, and estimated costs. In addition, recommendations are presented for implementing the proposed capacity improvement program.
How the Capacity Assessment Was Prepared
The City’s wastewater collection system includes sewer pipelines ranging in size from 4 to 48 inches in diameter. The larger pipes, primarily the 15-inch and larger sewers and a portion of the smaller diameter pipes, comprise the trunk sewer system, which is the primary network for conveying flows generated from the City’s service area to the SJ/SC WPCP. The trunk sewer system was the focus of the capacity assessment in this study.
(This page intentionally left blank)
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
Scott Blvd.
Machado Ave.
Monroe St.
Calabazas Blvd.
Chromite Dr. U.P.R.R.
Walsh Ave.
Central Expwy.
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Parcels
Pump Stations
Sewers by Size
6" and smaller
8" - 10"
12" - 16"
18" - 24"
27" - 48"
Sewer System
Figure ES-1
Flow from
CuSD
Flow To
SJ/SC WPCP
Flow To CSJ
Interceptor in
Zanker Rd
City of Santa Clara Sanitary Sewer Capacity Assessment Executive Summary May 2007 ES-3
The project team used a systematic process that incorporated land use planning information, water use and flow monitoring data, and design criteria for estimating wastewater flows into a computer hydraulic model of the trunk sewer system. The modeled system is shown in Figure ES-2. The model was used to assess how the system would perform under various planning scenarios and identifies pipes that may not have sufficient capacity to convey the predicted flows under future conditions. Improvement projects were developed to provide the required capacity, the capital costs of the required projects were estimated, and the projects were prioritized based on the model results and anticipated timing of development.
Capacity Assessment Considers Existing and Future Planning Scenarios Two planning scenarios, defined based on planning information and discussions with the City’s Planning Department staff, were evaluated for this study. The Existing Scenario examined the current capacity of the sewer system based on existing development and flow monitoring data collected in early 2006. The Future Scenario assumed construction of all currently planned major development and redevelopment projects in the City, as well as potential increased densities in mixed use and transit-oriented mixed use and commercial/office areas consistent with the City’s 2010 General Plan and General Plan Update.
Figure ES-3 shows the location of these planned and recently constructed developments. Planned development and redevelopment represents over 10,000 new residential dwelling units and over 5 million square feet of new commercial and office space. The Future Scenario was used to examine the impact on the system of future increases in wastewater flows due to new development and redevelopment and determine the required sewer system capacity needed to serve that development.
Potential Capacity Deficiencies Were Identified for Future Flow Conditions For each of the planning scenarios examined, projected dry and wet weather flows were simulated in the hydraulic model. The model was calibrated to actual flow monitoring data to ensure that it represents an accurate depiction of system conditions. For this study, a wet weather flow monitoring program consisting of 26 temporary flow meters installed in the system for a period of two months was used to calibrate the hydraulic model and verify existing system flows.
The model integrates various dry and wet weather flow parameters to determine system capacity under different flow and planning scenarios. Key flow components incorporated into the model included: base (dry weather) wastewater flow, estimated based on winter water use data; groundwater infiltration, which occurs when water seeps into pipes under the ground through cracks and pipe joints; and rainfall-induced infiltration and inflow (I/I) during storm events. For this Capacity Assessment, a 10-year recurrence frequency rainfall event was selected as the “design storm” to be consistent with the criteria used by the City of San Jose. The flow during a 10-year design storm represents a peak wet weather flow condition that would be expected to occur, on average, no more frequently than once every ten years.
Table ES-1 presents the estimated existing and future average dry weather flow (ADWF) and peak wet weather flow (PWWF) for a 10-year design storm for the City’s sewer system developed based on the modeling conducted for this study.
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
Scott Blvd.
Machado Ave.
Monroe St.
Calabazas Blvd.
Chromite Dr. U.P.R.R.
Walsh Ave.
Central Expwy.
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Modeled Pump Stations
Pump Stations Not in Model
Modeled Trunk Sewers
Sewer Mains
Parcels
Modeled System
Figure ES-2
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4767 Lafayette St. Detached Family
Home Project
BAREC Area
Train Station
Area
El Camino
Intensification
Downtown Revitalization
Kohl's Site
Taylor Woodrow/BRE
Cherry
Orchard Place
Valley Fair
Mall Expansion
Old Kaiser
Campus Site
Extreme
Networks
North SC Intensification
Future Hotel
Development
HP/ Agilent
Applied Materials
Kaiser
New Hospital
Rivermark
Hyatt Hotel Expansion &
Santa Clara Convention
Center Expansion
Citation Project
Yerba Buena/ Irvine
Santa Clara
University Classroom
Expansion
Marvell
Intel (Juliet site)
Shea Project
Sobrato Project
Intel (Freedom Site)
3600 Pruneridge
Ave. Residential
Project
Vidovich Project
(Homes and Retail)
2250 El Camino Real
Condominiums
(Sal Caruso)
Legend
City Boundary
Parcels
Planned Development/Redevelopment Projects
Commercial/Office/R&D
Residential
Commercial/Residential
Land Use Intensification
Mixed Use
Transit Oriented Mixed Use
Commercial/Office
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity Analysis
Planned
Development/Redevelopment
Figure ES-3
City of Santa Clara Sanitary Sewer Capacity Assessment Executive Summary May 2007 ES-6
Table ES-1 Sewer System Flow Estimates
Existing Flow
(mgd)
Future Flow
(mgd)
System Outfall ADWF PWWF ADWF PWWF
North (to Northside
and Rabello Pump
Stations)
17.7 40.8 21.2 43.1a
East (to San Jose
Trimble Road trunk
sewer)
6.0 13.2 6.9 14.1
Total 24 54 28 57
(a) Assumes peak flow from Cupertino Sanitary District flow does not increase above its contracted maximum capacity of 13.8 mgd.
Model results were examined to determine trunk system capacity needs, as indicated by areas where the flow in the pipes would exceed their capacity and cause surcharge conditions (water levels higher than the tops of the pipes) under peak wet weather flows. Figure ES-4 shows the existing trunk sewers that were determined by the modeling to have insufficient capacity to handle future flows.
The Proposed Improvement Projects Address the Potential Capacity Deficiencies To address the capacity deficiencies identified through the modeling effort, three primary types of capacity relief alternatives were explored:
▪ Upsizing pipes (i.e., replacing existing pipes with larger ones) ▪ Construction of parallel pipes
▪ Flow diversions to other sewers with available capacity or to new sewer pipelines Potential flow routing and capacity improvement alternatives were developed and tested, and proposed improvements were verified using the hydraulic model. Field visits were conducted to each proposed project site to identify site constraints and assess potential construction conditions, methods, and issues.
Based on these analyses, recommended capacity improvement projects were developed.
Figure ES-5 and Table ES-2 present the recommended capacity improvement projects. Note that the recommended plan reflects the construction of a new siphon crossing Calabazas Creek at El Camino Real, which is currently being designed as part of channel improvements being constructed by the Santa Clara Valley Water District (SCVWD). As part of that project, the City is coordinating with SCVWD to divert flows from the siphon outlet to the existing 24-inch Calabazas trunk sewer, thereby alleviating the predicted capacity deficiencies in El Camino Real east of Calabazas Creek and in the 8-inch sewer in the west side of Calabazas Boulevard north of El Camino Real.
The overall capacity improvement plan also shows a “West-to-East Trunk Alternative,” which is an alternative to constructing a major relief trunk sewer in Bowers Avenue and Great America Parkway (Projects 1 and 2), two of the busiest roads in the City that already contain large diameter sewer pipelines.
The West-to-East alternative would likely be easier to construct and could provide additional benefits, including greater system flexibility and potential reduction in costs for pumping flows that now are conveyed to the City’s Rabello and Northside Pump Stations. However, more detailed alignment studies and constructability evaluations would be needed to reach a final decision on whether the Bowers/Great America Parkway relief sewer or West-to-East Trunk is the most viable alternative.
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Predicted Capacity Deficiencies
Modeled Trunk Sewers
Parcels
Predicted Capacity
Deficiencies
Figure ES-4
Monroe St.
Machado Ave.
Chromite Dr. U.P.R.R.
Central Expwy.
Walsh Ave.
Calabazas Blvd.
Scott Blvd.
(This page intentionally left blank)
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
5 Scott Blvd.
Machado Ave.
Monroe St.
Calabazas Blvd.
Chromite Dr.
U.P.R.R.
Walsh Ave.
Central Expwy.
6 2
1 West-to-East
Trunk Alternative
4A
8 9
4B
10 ECR
Diversion
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Capacity Improvement Projects
Modeled Trunk Sewers
Parcels
Recommended Capacity
Improvement Projects
Figure ES-5
City of Santa Clara Sanitary Sewer Capacity Assessment Executive Summary May 2007 ES-9
Table ES-2 Recommended Capacity Improvement Projects
Project
No.a Location US MH DS MH Length
(ft.)
Exist.
Dia. (in.)
Req'd. Dia.
(in.)b
1 Augustine Dr., Lakeside Dr., crossing of U.S.
101, Mission College Boulevard, Great
America Pkwy. from Bowers Ave. to south of
Hetch Hetchy ROW
S73-20 S93-57 7,200 33-36 21 (P)
2 Chromite Dr., Alhambra Dr., Bracher Park,
crossing of UPRR, Bowers Ave. from Bowers
Ave. to Augustine Dr.
S53-34 S73-20 6,200 27-33 21 (P)
West-toEast
Trunkc
Chromite Dr., Alhambra Dr., Bracher Park,
crossing of UPRR, Walsh Ave., Lafayette,
Lafayette St., Central Expwy. From Bowers Dr.
to UPRR
S53-41 S67-18 12,200 NA 24
4A Monroe St. and Chromite Dr. from Machado
Ave. to west of Bowers Ave. S52-80 S53-41 2,200 18 24-27 (R) 4B Machado Ave. from Calabazas Blvd. to
Monroe St. S52-103 S52-80 1,500 15 21 (R)
5 Monroe St. from Fordham Dr. to Chromite Dr. S51-22 S52-65 2,500 10 8(siphon)
12 (R)
8(siphon) (P)
6 Nobili Ave. and Machado Ave. from Flora Vista
Ave. to Calabazas Blvd. S41-53 S52-101 3,100 10-15 15-18 (R) 8 El Camino Real from Flora Vista Ave. to
Calabazas Blvd. S41-113 S32-5 2,600 10 12-15 (R)
9 Scott Blvd. from Serra Ave. to Homestead Rd. S25-37 S35-98 800 8 10 (R) 10 Park Ave. south of Bellomy St. S38-75 S38-66 250 10 12 (R) (a) Note: there are no projects 3 and 7.
(b) P = parallel sewer; R = remove and replace
(c) Alternative to Projects 1 and 2.
Recommended Capacity Improvement Program
The Capital Improvement Program (CIP) recommended in this study is designed to provide for adequate sewer system capacity for the City’s existing and anticipated future development. The total estimated capital cost of the CIP is approximately $20 million, as shown in Table ES-3. These costs include baseline construction costs for gravity trunk sewers using open-cut and trenchless (e.g., microtunneling) methods, costs for lower lateral replacement for remove-and-replace projects, costs for major sewer junction and siphon structures, and costs allowances for project mobilization/demobilization, traffic control, bypass pumping and delay factors for remove-and-replace projects, extra dewatering requirements in areas of high groundwater, and acquisition of temporary and permanent easements if needed. The total estimated capital costs also include a 30 percent allowance for contingencies for unknown conditions and an allowance of 25 to 35 percent of construction cost (depending on project size) for engineering, administration, and legal costs. The estimated costs are considered planning or conceptual level estimates and are considered to have an estimated accuracy range of -30 to +50 percent.
The recommended projects were divided into the two priority groups based on the relative magnitude of predicted capacity deficiencies, as well as the likely timing of developments that may impact the need for the projects. The priority groups are also shown in Table ES-3.
City of Santa Clara Sanitary Sewer Capacity Assessment Executive Summary May 2007 ES-10
Table ES-3 Project Costs and Priority Groups
Project No.
Estimated
Construction
Cost ($)
Estimated Capital
Cost ($)
2 5,286,000 7,324,000
4A 1,489,000 1,861,000
8 945,000 1,276,000
Subtotal 7,720,000 10,461,000
1 4,539,000 5,674,000
4B 1,060,000 1,325,000
5 1,046,000 1,308,000
6 1,139,000 1,424,000
9 256,000 346,000
10 77,000 104,000
Subtotal 8,117,000 10,181,000
Total 15,837,000 20,642,000
West-to-East Alternativea 9,752,000 12,906,000
Total w/West-to-East
Alternative 15,764,000 20,550,000
Priority Group 1
Priority Group 2
(a) Would replace Projects 1 and 2 and be included in Priority Group 1.
A preliminary schedule for completion of the recommended CIP projects over a five-year period was developed based on the project priorities. Figure ES-6 shows a preliminary schedule for the recommended five-year CIP. Two schedules are provided to reflect the two major alternatives. However, the schedules also provide for a preliminary alignment study of both the Bowers/Great America Parkway and the West-to-East trunk alternatives. Note also that the schedule could be compressed to achieve greater economy of scale and potential cost savings by combining individual projects and/or using alternative bid schedules.
Implementation Recommendations
The City should begin implementation of the Capital Improvement Program recommended in this Sanitary Sewer Capacity Assessment, starting with the highest priority projects. The following items should be considered in project scheduling and design, and in future updates of the Capacity Assessment. ▪ The alignments and sizes of all recommended projects should be verified with detailed predesign analyses, including topographic surveys, geotechnical investigations, utility research, and constructability reviews.
▪ The decision to parallel or replace existing sewers should consider the physical condition and remaining useful life of the existing pipelines; the availability of pipeline corridors for new sewer construction; and operation and maintenance concerns.
▪ The hydraulic model has been developed to assist the City in performing capacity analyses and updating the Capacity Assessment in the future. The model should be kept up-to-date with any changes to existing sewer connections, development plans, and sewer system facilities.
City of Santa Clara Sanitary Sewer Capacity Assessment Executive Summary May 2007 ES-11
Figure ES-6 Proposed CIP Schedule
With Projects 1 and 2
Alignment Study
Project 8
Project 4A
Project 2
Project 1
Project 4B
Projects 5&6
Projects 9&10
With West-to-East Trunk Alternative
Alignment Study
Project 8
Project 4A
West-to-East Trunk
Project 4B
Projects 5&6
Projects 9&10
Planning
Design
Bid and Award
Construction
Project Year 1 Year 2 Year 3 Year 4 Year 5
Project Year 1 Year 2 Year 3 Year 4 Year 5
▪ The City should periodically calibrate its permanent flow meters at the Northside and Rabello Pump Stations and on the Trimble Road trunk sewer to ensure that accurate flow information is available to track the changes in the flows in the City’s system over time. ▪ The City should conduct additional flow monitoring at key locations in the sewer system, particularly the area tributary to the Chromite/Machado trunk sewers where the 2006 flow monitoring indicated high I/I flows. Flow levels during large storm events should be compared to the peak flows simulated by the hydraulic model to verify the modeling predictions for the 10-year design storm and confirm the need for and sizing of Projects 4A, 4B, 5, and 6.
▪ The City should consider additional field investigations, including smoke testing, and manhole and pipeline television inspection, in this area to identify potential sources of I/I and possible opportunities for I/I reduction.
▪ The City should coordinate with the Cupertino Sanitary District on flow and planning assumptions to ensure that adequate capacity exists in the Santa Clara system to handle future flows from CuSD.
The City should encourage CuSD to verify the calibration of its flow meter at Homestead Road and confirm its projections of future wastewater flows entering the Santa Clara system. ▪ The City should coordinate with the City of San Jose to ensure that its flow criteria and planning assumptions are consistent with those used by San Jose in its capacity master planning. ▪ The City should assess its connection fees and evaluate financial alternatives to fund the recommended capacity assessment CIP.
This Sanitary Sewer Capacity Assessment report is intended to be a working document to be refined and updated as additional data and new planning information becomes available. The Capacity Assessment should be updated whenever there are major changes in planning assumptions or, at a minimum, every five years.
Introduction
Chapter 1
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 1 Introduction May 2007 1-1
Chapter 1 Introduction
This report presents the results and recommendations of the Sanitary Sewer Capacity Assessment for the City of Santa Clara (City). The report was prepared by RMC Water and Environment (RMC).
1.1 Background and Study Objectives
The City of Santa Clara is located in central Santa Clara County and is bounded by the City of San Jose on the north, east and south, the City of Cupertino on the southwest, and the City of Sunnyvale on the west. As shown in Figure 1-1, the capacity assessment study area compromises the area within the Santa Clara city limits.
The City is experiencing significant growth and redevelopment, necessitating an evaluation of the capacity of the sanitary sewer system to handle future wastewater flows. This evaluation will help identify future capital needs for capacity improvements and associated requirements for financing those improvements through increased connection fees or other sources of funding.
Furthermore, the City is also required to complete a capacity evaluation and capacity assurance plan as part of preparing its Sewer System Management Plan (SSMP). The SSMP addresses the overall management, operation, and maintenance of the sanitary sewer system and is required for all sewer system agencies by the Regional Water Quality Control Board (Regional Board), as well as under the Statewide General Waste Discharge Requirements adopted in 2006 by the State Water Resources Control Board (State Board).
The overall objectives of this Capacity Assessment study are to develop wastewater flow projections for the City’s collection area using up-to-date water use and land use information; develop a hydraulic model of the trunk sewer system; use the model to identify existing capacity deficiencies and future capacity requirements; and develop a phased Capital Improvement Program, including budget estimates, for implementing the required capacity improvements to the wastewater collection system.
1.2 Wastewater Collection System
The City’s wastewater collection system includes approximately 270 miles of sewer pipelines ranging from 4 to 48 inches in diameter, and six sewage pump stations. Flow from Cupertino Sanitary District enters the City’s sewer system at Homestead Road. The collection system conveys wastewater to the San Jose/Santa Clara Water Pollution Control Plant (SJ/SC WPCP), located north of Highway 237 in San Jose. The City of Santa Clara collection system is shown in Figure 1-2.
1.3 Scope of Study
RMC was authorized by the City to provide engineering consulting services for the Sanitary Sewer Flow Monitoring Program and Sanitary Sewer Capacity Assessment under an Agreement with the City dated December 13, 2005, and amended March 21, 2006.
The scope of the Capacity Assessment, as well as a brief discussion of work conducted under each task, is described below.
Task 1 – Project Management and Quality Control. Periodic progress meetings were held with the City staff to review project status and discuss project issues, and monthly status reports were prepared to document the work completed. Quality control was carried out, including checking of data and calculations, as well as senior review of proposed criteria, recommendations, and project deliverables.
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Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd.Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
Scott Blvd.
Machado Ave.
Monroe St.
Calabazas Blvd.
Chromite Dr.
U.P.R.R.
Walsh Ave.
Central Expwy.
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Parcels
Study Area
Figure 1-1
(This page intentionally left blank)
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
Scott Blvd.
Machado Ave.
Monroe St.
Calabazas Blvd.
Chromite Dr. U.P.R.R.
Walsh Ave.
Central Expwy.
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Parcels
Pump Stations
Sewers by Size
6" and smaller
8" - 10"
12" - 16"
18" - 24"
27" - 48"
Sewer System
Figure 1-2
Flow from
CuSD
Flow To
SJ/SC WPCP
Flow To CSJ
Interceptor in
Zanker Rd
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 1 Introduction May 2007 1-4
Task 2 – Flow Monitoring Site Selection. Sanitary sewer system maps and previous reports were reviewed in order to delineate the trunk sewer network and refine major sewer basins and subbasins.
Meter and rain gauge sites were identified, investigated, and finalized. A flow monitoring plan with a listing and map of the final sites, schedule for the field work and site traffic control plans was prepared.
Task 3 – Flow Monitoring. A flow monitoring program, consisting of the 26 meters and 3 rain gauges installed in the collection system for a period of about two months during the 2005-2006 wet weather season, was conducted to obtain data to characterize flows in the system and calibrate the hydraulic model. In addition, two existing City-owned ISCO flow meters were also calibrated and utilized for the study.
Task 4 – Flow Monitoring Report. A flow monitoring report containing copies of monitor site reports, weekly plots of flow and rainfall, and summary tables of average, minimum, and maximum daily flows for each meter was submitted to the City. In addition, all data in electronic format were also submitted.
Task 5 - Compile and Review Existing Information. This task involved assembling, organizing, reviewing maps and documents, and compiling the information in a format that was useful for subsequent tasks.
Task 6 – Develop Land Use Planning Information and Parcel Loads. Meetings were held with the City Planning staff to identify and obtain pertinent land use planning data, vacant land inventory and other information required for the Capacity Assessment, and to discuss specific planning issues and potential growth or redevelopment areas in the City. The City’s 2010 General Plan and General Plan Amendment were reviewed. Water use data was compiled for existing customers. The information collected was used to develop estimates of existing and future wastewater flows. Task 7 – Develop Design Flow and Hydraulic Criteria. This task involved developing criteria used for estimating wastewater generation and wet weather flows in the sanitary sewer system. ).
Design flow criteria were developed, including base wastewater flow and infiltration/inflow factors, as well as an appropriate design storm to be used for analyzing and determining the required capacity of sewer system facilities. Hydraulic criteria were proposed for evaluating and sizing system facilities for the capacity assessment.
Task 8 – Develop Hydraulic Model. In this task, the model network files were built using the District’s mapping and sewer inventory files and additional data developed for this project. A digital sewer subbasin map was developed for the model. Flow input data for the model were compiled using the water use and land use data and design flow criteria developed under previous tasks. The model was verified for system connectivity, calibrated for dry weather conditions, and then calibrated for wet weather conditions using actual storm events from the flow monitoring program. Task 9 – Evaluate System Hydraulic Performance. Under this task, the model was used to determine collection system capacity requirements for peak dry and wet weather conditions. The model runs identified capacity deficiencies in the existing system and the required system capacity to serve future development. Preliminary solutions to capacity deficiencies were identified and tested in the model.
Task 10 – Model Training and Support. Training of City staff in use of the model was deferred until after completion of the study.
Task 11 – Develop Capital Improvement Projects. Detailed analysis was conducted to refine and further develop the proposed solutions for capacity deficiencies. This work included investigation of alternative alignments and assessment of design and constructability issues.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 1 Introduction May 2007 1-5
Task 12 – Develop Sewer System Capital Improvement Program. Unit construction costs for components of sewer construction were developed, and estimated capital costs for the recommended improvement projects were prepared. In conjunction with City staff, the recommended improvement projects were prioritized, and a phased Capital Improvement Program (CIP) was developed. Task 13 – Prepare Capacity Assessment Report. This report was prepared to summarize and present the results and recommendation of the study.
1.4 Report Organization
This report includes six sections, which are described below. Section 1, Introduction, presents the background, objectives, and scope of the Sanitary Sewer Capacity Assessment.
Section 2, Land Use and Flow Estimates, discusses the planning area land use projections, the basis for developing estimates for each component of wastewater flows, and the flow projections for the service area.
Section 3, Hydraulic Model Development, describes the modeled sewer system, development of the model network and model loads, and model calibration.
Section 4, Capacity Analysis, describes the capacity analysis and design criteria, model results, and preliminary solutions for identified capacity deficiencies. Section 5, Capacity Improvement Projects, explains the process for development of capacity improvement projects, and presents the recommended projects. Section 6, Recommended Capital Improvement Program, presents the recommended CIP, including project costs, prioritization, CIP schedule, and implementation recommendations.
The Appendices to this report include plots of the flow monitoring data and documentation for the recommended CIP, including project descriptions and cost estimates. (This page intentionally left blank)
Land Use and Flow Estimates
Chapter 2
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-1
Chapter 2 Land Use and Flow Estimates
This chapter presents the land use and design wastewater flow estimates for the City of Santa Clara. The section describes existing and projected future land uses for the City, which form the basis for generating flows in the hydraulic model. Flow monitoring was conducted to verify existing flows in major trunk sewers. Design flow estimates were developed based on criteria developed for each flow component:
base wastewater flow, groundwater infiltration, and rainfall-dependent infiltration and inflow.
2.1 Land Use Projections
Land use data form the basis for estimating wastewater flows in the sewer system. Land use data for the City of Santa Clara are based on the City’s 2010 General Plan and General Plan Amendment, and information on specific developments provided by the City’s Planning Department.
2.1.1 Planning Scenarios
The Sanitary Sewer Capacity Assessment Project includes two modeling scenarios: Existing and Future.
For the purposes of this Capacity Assessment, the Existing Scenario was defined as current development as of winter 2005-2006. Actual water use data were used to estimate wastewater flows for the existing scenario, and flow monitoring data collected during this time period were used to calibrate the hydraulic model for existing flows.
The Future Scenario assumes construction of all currently planned major development and redevelopment projects in the City, as well as potential increased densities in mixed use and transit-oriented mixed use and commercial/office areas consistent with the City’s current General Plan. The future scenario was used to examine the impact on the system of future increases in wastewater flows due to new development and redevelopment.
RMC met with the City’s Planning Department in July 2006 in order to identify planned development and redevelopment for the Future Scenario. Table 2-1 lists the planned development and redevelopment projects based on information provided by the Planning Department and compiled from the General Plan and General Plan Amendment. It includes the following categories of development/redevelopment:
• Developments under construction or recently constructed • Planned developments, approved
• Planned developments, not yet approved
• Land use intensification per General Plan and General Plan Amendment, no specific development plan available
Figure 2-1 shows the locations of these planned and recently constructed developments. Table 2-2 summarizes the quantity of residential and non-residential development represented by the planned developments listed in Table 2-1 and shown in Figure 2-1.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-2
Table 2-1 Planned Development/Redevelopment
Name Type a Planned
Development b, c
Intel (Juliet site) Commercial 100,000 SF
Intel (Freedom site) Commercial 400,000 SF
Applied Materials R&D 840,000 SF
Kaiser -New Hospital Commercial 675,000 SF
HP/ Agilent R&D 727,500 SF
Marvell Site (previously 3Com Pal) R&D 278,000 SF
Yerba Buena/ Irvine Commercial 910,000 SF
Hotel Development (previously Marriott) Hotel 225 Rooms Commercial 8,800 SF Vidovich Project Multi Family 64 DU Santa Clara University Commercial 250,000 SF
Citation Project Single Family 413 DU
Sobrato Project Apartment 306 DU
3600 Pruneridge Single Family 31 DU
Multi Family 2 DU
Shea Project Multi Family 130 DU
4767 Lafayette St Single Family 27 DU
Hyatt Regency Hotel Expansion (previously Westin) Hotel 250 Rooms 2250 El Camino Real (Sal Caruso) Condominiums 45 DU
Citation Project 2 Multi Family 59 DU
Rivermark Multi Family 964 DU
Taylor Woodrow/BRE Single Family 63 DU
Rental Condominiums 277 DU
Kohl's Site Development Condominiums 490 DU
Commercial 52,300 SF
Extreme Networks TOMU 15 Acres
Santa Clara Convention Center New Ballroom Commercial 24,000 SF Valley Fair Mall Expansion Commercial 22,000 SF
Downtown Revitalization MU 7 Acres
Train Station Area MU 17 Acres
BAREC Area Single Family 110 DU
Multi Family 165 DU
El Camino Real Intensification MU 9 Acres
North Santa Clara Intensification Higher Intensity Office 524 Acres Cherry Orchard Place Single Family 14 DU
Old Kaiser Campus Medium Density Residential 27 Acres
General Plan Developments MU 142 Acres
General Plan Developments TOMU 62 Acres
(a) R&D = Research & Development; MU = Mixed Use; TOMU = Transit-Oriented Mixed Use; Multi Family = condominiums/townhouses
(b) DU = dwelling units; SF = square feet
(c) MU and TOMU assumed to be moderate and medium density residential, respectively (added to existing commercial area)
4767 Lafayette St. Detached Family
Home Project
BAREC Area
Train Station
Area
El Camino
Intensification
Downtown Revitalization
Kohl's Site
Taylor Woodrow/BRE
Cherry
Orchard Place
Valley Fair
Mall Expansion
Old Kaiser
Campus Site
Extreme
Networks
North SC Intensification
Future Hotel
Development
HP/ Agilent
Applied Materials
Kaiser
New Hospital
Rivermark
Hyatt Hotel Expansion &
Santa Clara Convention
Center Expansion
Citation Project
Yerba Buena/ Irvine
Santa Clara
University Classroom
Expansion
Marvell
Intel (Juliet site)
Shea Project
Sobrato Project
Intel (Freedom Site)
3600 Pruneridge
Ave. Residential
Project
Vidovich Project
(Homes and Retail)
2250 El Camino Real
Condominiums
(Sal Caruso)
Legend
City Boundary
Parcels
Planned Development/Redevelopment Projects
Commercial/Office/R&D
Residential
Commercial/Residential
Land Use Intensification
Mixed Use
Transit Oriented Mixed Use
Commercial/Office
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity Analysis
Planned
Development/Redevelopment
Figure 2-1
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-4
Table 2-2 Planned Development Summary
Type of Development/Redevelopment Quantity Units
Single Family 658 DUs
Condominiums/Townhouses 2,196 DUs
Apartments 306 DUs
Hotel 475 Rooms
Commercial 2,442,100 Sq. Ft.
R&D 1,845,500 Sq. Ft.
Commercial/Office Intensification a 913,018 Sq. Ft.
Additional Mixed Use per GP b 4,444 DUs
Additional Transit-Oriented Mixed Use per GP c 2,772 DUs
Total Additional DUs 10,376
Total Additional Sq. Ft. Commercial/Office/R&D 5,200,618 (a) Assumes increase in floor-area-ratio (FAR) on 0.04. (b) Assumes residential density of 22 DU/acre.
(c) Assumes residential density of 36 DU/acre.
2.2 Flow Monitoring Program
Flow monitoring was conducted by field services staff of E2 Consulting Engineers, subcontractor to RMC, to obtain data to quantify flows in the system and enable analysis of wet weather infiltration/inflow (I/I) and calibration of a hydraulic model. The flow monitoring program consisted of 26 flow meters and three rain gauges operating for a period of approximately ten weeks.
The flow monitoring sites are listed in Table 2-3 and shown on Figure 2-2. The meters were installed from January 19 to 24, 2006, and most were removed on about April 3. Five of the meters were left in place for a few additional weeks to further verify meter calibration parameters. The meter sites utilized Sigma 910 meters with pressure depth transducers and Doppler velocity sensors. Along with the 26 meters, two existing City-owned ISCO flow meters installed on the parallel 33-inch lines at the east side of Santa Clara near Highway 101 were also calibrated per the City’s request. In addition, Cupertino Sanitary District has a flow monitor installed at Homestead Road to measure sewer flows that enter Santa Clara at the western city limits; RMC also obtained data from this meter during the flow monitoring period.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-5
Table 2-3 Flow Monitoring Locations
Flow
Monitor Location
Manhole
Number
Pipe Size
(in.)
1 Easement off of Lafayette St. north of Calle De Mundo S104-23 33 2 Lafayette St. north of Calle de Mundo S104-30 42
3 Primavera Lift Station S105-34 24
4 Lafayette St. south of Calle De Luna S104-36 36
5 Montague Expwy. east of Lafayette S86-17 18
6 Lafayette at Montague Expwy. S86-20 30
7 Mission College Blvd. north of Our Lady's Way S83-21 33 8 Mission College Blvd. north of Our Lady's Way S83-22 33 9 Calabazas Creek south of Kifer Rd. S62-40 24
10 Bowers Ave. at Chromite Dr. S53-34 30
11 Chromite Dr. at Bowers Ave. S53-41 18
12 Scott Blvd. south of Central Expwy. S65-34 24
13 Scott Blvd. south of Central Expwy. S65-33 18
14 Central Expwy. west of UPRR S67-16 27
15 De La Cruz Blvd. south of Central Expwy. S67-26 48
16 Brokaw Rd. north-east of UPRR S48-36 18
17 Benton St. west of The Alameda S38-1 12
18 Los Padres Blvd. at Bray Ave. S45-80 18
19 Los Padres Blvd. at Karen Dr. S25-1 15
20 San Tomas Expwy. at Warburton S44-57 15
21 Bowers Ave. south of Warburton S43-86 27
22 Kiely Blvd. north of Homestead S23-20 18
23 Saratoga Creek west of Kiely Blvd. S23-12 21
24 Homestead Rd. east of Bing Dr./Princeton Way S2147 18 25 Homestead Rd. east of Bing Dr./Princeton Way S21-54 15 26 Wren Ave. at Lerwick Ct. S21-23 24
During the flow monitoring period, all of the monitoring sites were visited weekly to check meter operation and site conditions, obtain field calibration measurements, and download collected data. Field calibration involves taking manual depth measurements and flow velocity measurements using a portable velocity meter. These calibration measurements were compared to and used to adjust monitor-recorded depth and velocity if needed. Calibration measurements were taken at different times of day in order to obtain calibration points for the full range of typical diurnal flows.
Three rain gauges were installed to collect representative rainfall over the service area during the monitoring period. The rain gauge locations were:
Rain Gauge 1: Santa Clara Corporation Yard
Rain Gauge 2: Primavera Pump Station
Rain Gauge 3: Santa Clara Tank Site, off of Highway 280 and Lawrence Expressway Approximately 12 storm events occurred during the flow monitoring period, totally about six inches of rainfall. Most of the events, however, were relatively small. The duration and the total rainfall for each event are summarized in Table 2-4.
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Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
Flow from
CuSD
9 8
7 6
5 3
4 2
1 26
25 24
23 22
21 20
19 18 17 16
15 14 13
12 11
10 ISCO-23
ISCO-01
3 1
2 0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Flow Meter and ID 5
Rain Gauge and ID 1
Modeled Trunk Sewers
Sewer Subbasins
Parcels
Flow Meter Sites
Figure 2-2
Machado Ave.
Monroe St. Chromite Dr. U.P.R.R.
Walsh Ave.
Central Expwy.
Scott Blvd.
Calabazas Blvd.
Flow To
SJ/SC WPCP
Flow To CSJ
Interceptor in
Zanker Rd
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-7
Table 2-4 Rain Events during Flow Monitoring Period
Start Duration Storm Rainfall (in.) Max. Hour (in.)
Date/Time
End
Date/Time (hours) Avg. RG1 RG2 RG3 RG1 RG2 RG3
2/17/06 12 PM 2/17/06 8 PM 8 0.23 0.20 0.19 0.31 0.09 0.08 0.15 2/26/06 11 PM 2/28/06 2 AM 27 1.16 1.14 0.99 1.34 0.17 0.16 0.19 3/2/06 12 AM 3/2/06 4 AM 4 0.27 0.25 0.30 0.27 0.10 0.14 0.10 3/3/06 1 AM 3/3/06 5 PM 16 0.26 0.42 0.03 0.32 0.19 0.02 0.13 3/5/06 3 PM 3/6/06 4 AM 13 0.68 0.56 0.66 0.81 0.12 0.13 0.13 3/10/06 6 PM 3/11/06 7 AM 13 0.23 0.28 0.26 0.15 0.08 0.12 0.06 3/13/06 11 PM 3/14/06 7 AM 8 0.38 0.34 0.39 0.42 0.10 0.14 0.12 3/16/06 9 PM 3/17/06 12 AM 3 0.39 0.39 0.37 0.40 0.26 0.26 0.24 3/20/06 10 AM 3/21/06 5 AM 19 0.74 0.71 0.92 0.58 0.22 0.24 0.18 3/24/06 5 PM 3/25/06 6 AM 13 0.61 0.53 0.65 0.66 0.13 0.13 0.19 3/29/06 3 AM 3/29/06 10 AM 7 0.20 0.18 0.13 0.28 0.06 0.05 0.10 4/2/06 4 PM 4/3/06 2 PM 22 0.71 0.74 0.66 0.74 0.11 0.12 0.10 Following the completion of flow monitoring, E2 prepared a summary report containing copies of the meter site reports and photographs; 7-day graphs of the flow and rainfall data; and summary tables of minimum, maximum, and average daily flows and rainfall. In addition, electronic files of all data were provided to the City. The final flow monitoring report has been provided to the City as a separate attachment. Summary plots of the flow and rainfall data are included in Appendix A of this report.
2.3 Wastewater Flows
The components of wastewater flows and methodology for quantifying each flow component are discussed below.
2.3.1 Wastewater Flow Components
Wastewater flows include three components: base wastewater flow (BWF), groundwater infiltration (GWI), and rainfall-dependent infiltration/inflow (RDI/I), as illustrated conceptually in Figure 2-3. BWF represents the sanitary and process flow contributions from residential, commercial, institutional, and industrial users of the system. GWI is groundwater that infiltrates into defects in sewer pipes and manholes, particularly in winter and springtime in low-lying areas. GWI is typically seasonal in nature and remains relatively constant during specific periods of the year. RDI/I is storm water inflow and infiltration that enter the system in direct response to rainfall events, typically through direct connections such as holes in manhole covers or illegally connected roof leaders or area drains, or, more commonly, through defects in sewer pipes, manholes, and service laterals. RDI/I typically results in short term peak flows that recede quickly after the rainfall ends.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-8
Figure 2-3 Wastewater Flow Components
(Not to scale)
Flow
Rainfall
Time
(24 Hours)
RDI/I
BWF
GWI
2.3.2 Methods for Estimating Base Wastewater Flows
Base wastewater flow consists of the normal sanitary flow contribution from residential, commercial, institutional, and industrial users of the sewer system. Base wastewater flows are typically calculated by applying unit BWF factors (in gpd per acre or gpd per DU) to existing and/or future land use quantities.
For residential areas, BWF factors depend primarily on residential density and the average number of persons per dwelling unit. For commercial and industrial areas, BWF factors depend primarily on the type and distribution of the commercial and industrial establishments. Since BWF factors would be expected to be similar for communities with similar types of development, BWF factors are often developed based on published values and verified by flow monitoring or analysis of water consumption data for a particular community.
For the City’s Sanitary Sewer Capacity Assessment, BWF loads were developed for both existing and future development conditions. Existing loads were developed based on actual winter water use data from the City’s customer billing records, and future loads were based on projected development and redevelopment projects anticipated by the City. The unit flow factors used to compute BWF from future development are summarized in Table 2-5. The residential factors shown in the table are consistent with the City’s standard residential design flow rate of 70 gallons per capita per day (gpcd) and residential densities for various land use classifications. The rates per square foot for commercial/office and office/research & development (R&D) development are based on typical design factors used for other similar areas.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-9
Table 2-5 Base Wastewater Flow Unit Flow Factors
Type of Development Unit Flow Factor Basis
Single Family Detached 245 gpd/DU 3.5 people/DU @ 70 gpcd Townhouses/Condominiums 175 gpd/DU 2.5 people/DU @ 70 gpcd Apartments 154 gpd/DU 2.2 people/DU @ 70 gpcd
Hotels 100 gpd/room
Commercial/Office 0.1 gpd/sq. ft.
Office/R&D 0.15 gpd/sq. ft.
Moderate Density Residential
(Mixed Use) 3,200 gpd/acre 21 DU/acre @154 gpd/DU
Medium Density Residential
(Transit-Oriented Mixed Use) 4,600 gpd/acre 30 DU/acre @ 154 gpd/DU Commercial/Office/R&D
Intensificationa + 300 gpd/acre + 0.04 FAR @ 0.15 gpd/sq. ft. (a) Applied to areas of North Santa Clara where existing development is anticipated to increase in intensity from a current average floor-area-ratio (FAR) of 0.41 to a future average of 0.45.
2.3.3 Diurnal Base Wastewater Flow Patterns
In most sewer systems, BWF exhibits typical diurnal patterns depending on the type of land use. For Santa Clara, typical diurnal curves were developed for residential, commercial, and industrial areas, for both weekend and weekday conditions. These curves are shown in Figure 2-4. Each area of the system was assigned a diurnal curve according to its predominant land use type.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-10
Figure 2-4 Diurnal Curves
0.0 0.2
0.4 0.6
0.8 1.0
1.2 1.4
1.6 1.8
2.0 0 3 6 9 12 15 18 21 24
Hour
Ratio to Average Flow
Residential Weekend Residential Weekday
0.0 0.2
0.4 0.6
0.8 1.0
1.2 1.4
1.6 1.8
2.0 0 3 6 9 12 15 18 21 24
Hour
Ratio to Average Flow
Commerical Weekday and Weekend
0.0 0.2
0.4 0.6
0.8 1.0
1.2 1.4
1.6 1.8
2.0 0 3 6 9 12 15 18 21 24
Hour
Ratio to Average Flow
Industrial Weekend Industrial Weekday
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-11
2.3.4 Large Users
For purposes of this study, a “large” discharger was defined as one discharging more than an average of 40,000 gallons per day (gpd) average flow or 50,000 gpd maximum month flow during the winter months. Based on winter 2005-2006 water and recycled water billing records provided by the City, there are eighteen large dischargers that meet the criteria outlined above. Wastewater flows for large users were based on average winter flow.
All dischargers to the sewer system are included in the City’s water billing database and are therefore accounted for in the calculation of existing BWF loads. However, some large dischargers do not exhibit typical industrial diurnal wastewater flow patterns and therefore must be accounted for separately.
Typically, these are users that discharge wastewater on a relatively constant basis, 24 hours per day and 7 days per week (24/7). These users were given separate constant diurnal profiles in the hydraulic model.
Table 2-6 lists the eighteen large dischargers in the Santa Clara system and those that are considered 24/7 users.
Table 2-6 Large Dischargers
Large Water User APN Address Average Flow a
(gpd)
Maximum
Month Flow a
(gpd)
KOLL 104-13-090 2151 Mission College Blvd 934,461 1,101,270
CONTAINER CORP OF
AMERICA b,c 230-03-100 2600 De La Cruz Blvd 381,870 413,739
NEWARK GROUP
INDUSTRIES INC b,c 230-03-090 525 Mathew St 473,003 561,917 SILICONIX INC b 104-39-023 2201 Laurelwood Rd 411,666 422,353 DVR POWER PLANT d 224-36-047 850 Duane Ave 103,354 576,000 RENAULT 216-49-019 3320 Scott Blvd 165,222 181,586
OWENS-CORNING
FIBERGLAS CORP b,c 224-07-099 960 Central Expy 19,715 21,242 ANADITE INC 104-14-047 1440 Norman Ave 142,536 148,429
INTEL CORPORATION 104-48-010 3603 Juliette Ln 118,250 120,743 INTERNATIONAL INTEL 216-46-015 3065 Bowers Ave 91,713 97,439
AGILENT
TECHNOLOGIES INC 316-17-018 5301 Stevens Creek Blvd 88,963 131,152 SCP 2001PE LLC 104-13-083 2175 Mission College Blvd 88,922 98,976
APPLIED MATERIALS
INC 216-49-024 3070 Bowers Ave 88,129 100,579
DLC ASSOCIATES II 097-31-062 3495 De La Cruz Blvd 67,262 75,719 LEON MARDIROSSIAN 224-06-170 1415 Richard Ave 64,683 66,340
NATIONAL
SEMICONDUCTOR
CORPORATION
205-39-022 2900 Semiconductor Dr 57,636 72,896
SIGMA CIRCUITS INC 230-47-112 351 Mathew St 54,302 57,047
ADVANCED
CARDIOVASCULAR
SYSTEMS INC
216-30-040 3200 Lakeside Dr 35,261 51,453
(a) For December 2005 through March 2006 period.
(b) 24/7 discharger.
(c) Derived from water use data adjusted by a factor provided by the City. (d) Based on DVR Power Plant data provided by the City.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-12
2.3.5 Infiltration/Inflow
Infiltration/inflow is extraneous groundwater and storm water that enter the sewer system through illegal connections or defects in sewer pipelines, manholes, and service laterals. The primary types of I/I are groundwater infiltration and rainfall-dependent I/I.
Groundwater Infiltration
Groundwater infiltration is generally quantified based on actual flow monitoring data, since it is difficult to predict GWI rates based on physical system data alone. In the context of design flow criteria, GWI represents the incremental groundwater infiltration that occurs during the wet weather season above the “baseline” infiltration level during the driest months of the year.
GWI can be estimated based on minimum flows during non-rainfall periods during a wet weather flow monitoring period. Minimum flows typical occur during the nighttime or early morning hours when base wastewater flows are at a low. Alternatively, GWI can be estimated as the difference between average metered flow during non-rainfall periods and computed average BWF. In either case, the resulting GWI, is expressed on a unit basis (gpd/acre or gpad) by dividing by the sewered acreage of the monitored area.
Typical GWI rates may range from 100 to over 1,000 gpad.
GWI flows were estimated through the model calibration process (described in the next chapter of this report) by comparing model-simulated BWF to actual flow measurements from the temporary flow monitoring program conducted in January through April 2006. Cases where model-predicted BWF was noticeably lower than monitored flow indicated the possible occurrence of GWI.
Rainfall-Dependent I/I
RDI/I flows result from rainfall events that produce infiltration and inflow of storm water runoff into the sewer system. RDI/I can be quantified as the difference between the total flow during and immediately following a storm event and the non-rainfall “base flow” (BWF plus GWI) that is estimated to have occurred during the storm period. The magnitude of the resulting RDI/I response is typically described by the percentage of the rainfall volume (called the “R value”) represented by the volume of the RDI/I hydrograph. The R value can vary from storm to storm, depending on such factors as the degree of soil saturation (due to antecedent rainfall) prior to the storm event.
The shape of the RDI/I hydrograph is also important in determining the peak RDI/I response. The RDI/I hydrograph shape in often defined by separating the total RDI/I hydrograph volume into components, representing different response times to rainfall (fast, medium, and slow). Each component is identified by a percentage of the total RDI/I volume and specific time to peak (T) and recession coefficient (K), illustrated in Figure 2-5. The R component percentages and T and K values can be applied to each hour of rainfall to generate a “synthetic hydrograph” that approximates the volume and shape of the hydrograph from the actual observed event. These parameters, when applied to a different rainfall pattern, can be used to estimate the RDI/I response to that particular rainfall event. This methodology is used to synthesize RDI/I hydrographs for a “design storm” for collection system modeling.
Design criteria for RDI/I include design R values and hydrograph shape parameters and the hourly rainfall for the selected design storm event. As described in the next chapter of this report, R values and hydrograph parameters are determined through the process of model calibration, in which actual observed rainfall events are simulated in the hydraulic model, and the resulting model hydrographs are compared to the measured flows at flow meters locations. The RDI/I parameters are adjusted as needed to achieve the best match of modeled to monitored flows. Once calibrated, the model RDI/I parameters can be applied to a design storm to simulate wet weather flows for a design event.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-13
Figure 2-5 RDI/I Hydrograph Components
2.3.6 Design Event
Wastewater collection systems are typically sized for a specific “design” condition, often represented by a development condition (e.g., “buildout”) under a design wet weather event, in combination with a designated system performance criterion.
Generally, the performance criterion is defined by the maximum allowable water level in the system, which may be at the ground surface (i.e., “no overflows”), a specified distance below the ground (say 5 feet below the manhole rims), or more conservatively, by a maximum allowable flow depth to pipe diameter (d/D) ratio. The maximum d/D may vary by pipe size. A maximum allowable d/D of 1.0 (i.e., “no surcharge”) is commonly used, although a smaller value (e.g., 0.75) may be used for smaller diameter sewers to account for the greater potential for reduced capacity due to obstructions in the pipes, or to add more conservatism to sizing of new pipes.
The “design event” establishes the maximum recurrence frequency under which the design performance criterion can be exceeded. Thus, if the performance criterion is “no surcharge” and the recurrence T1
T2
T2 K2
T3 T3K3
RDI/I
R1
R2
R3
R = R1+R2+R3
P
P is rainfall intensity over 1 hour
Total Rainfall Volume = P x Drainage Area
1 hour
Triangular Hydrograph 1
(fast response)
Triangular Hydrograph 2
(medium response)
Triangular Hydrograph 3
(slow response)
Total RDI/I Hydrograph
Time
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-14
frequency is 10 years, then the system must be designed such that pipes would not surcharge any more frequently than once every 10 years.
In practice, the design event is often equated to a specified recurrence frequency rainfall event, which can be developed based on historical rainfall intensity-duration-frequency (IDF) statistics. The City of San Jose has adopted a 10-year design storm for its capacity assessment program. Based on IDF data and guidelines from the County of Santa Clara Storm Design Requirements, a synthetic 10-year, 24-hour design storm was determined for the San Jose Airport (see Figure 2-6 below) and applied to other areas of the system in proportion to average annual rainfall. Applying this approach to Santa Clara, the design rainfall would be approximately 1.0 to 1.2 times the San Jose Airport rainfall (varying over the service area from north to south).
Figure 2-6 10-Year Design Storm for San Jose Airport
10-Year, 24-hour Storm
0.00 0.10
0.20 0.30
0.40 0.50
0.60 0.70
0:00
2:00
4:00
6:00
8:00
10:00
12:00
14:00
16:00
18:00
20:00
22:00
Rainfall (in)
To develop the projected RDI/I flows for the design event, the RDI/I hydrograph parameters determined from the wet weather calibration would be applied to the design storm rainfall. Note that the design event can be superimposed on an average base wastewater flow condition, based on the assumption that the peak rainfall could potentially occur at any time of the day, or it can be constructed so that the peak RDI/I roughly coincides with the peak BWF for a typical residential diurnal pattern, providing a higher level of conservatism in the design flows. The City of San Jose utilizes the more conservative assumption for sewer system planning. Therefore for Santa Clara, it was recommended that the same design event criteria be used. This is a reasonable assumption given that peak wet weather flows in the Santa Clara sewer system are relatively low.
2.3.7 Flows from Cupertino Sanitary District
Flows from Cupertino Sanitary District (CuSD) enter the City’s sewer system on Homestead Road.
CuSD maintains a flow meter at the discharge point to the City’s system. Initially, data from the District’s meter was reviewed in order to estimate CuSD flows discharging into Santa Clara; however, the data was found to be inconsistent, with unexplained changes in average daily flows over the course of the City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 2 Land Use and Flow Estimates May 2007 2-15
10-month period (January through October 2006). It is believed that this meter may have been out of calibration and was calibrated at some point during the year.
As part of a separate study conducted for CuSD, RMC estimated existing and future average dry weather flow (ADWF) from CuSD based on data on sewer connections, land use, and population density. The existing flow from the metered area of CuSD (portion tributary to Santa Clara, which represents about 89 percent of the total service area flow) was estimated to be 4.9 mgd, which matches well to the total flows at the temporary meters immediately downstream of the CuSD discharge point. Therefore, for purposes of the Santa Clara model, this value was used as the existing CuSD flow. The RMC study estimates the total future (year 2030) ADWF for CuSD at about 7.2 mgd; therefore, a preliminary estimate of future ADWF from CuSD entering the Santa Clara system at Homestead Road is 6.4 mgd (89 percent of the total future flow).
2.3.8 Wastewater Flow Estimates
The estimated existing and future average dry weather flow (ADWF), peak dry weather flow (PDWF), and design storm PWWF flows for the City’s system were developed based on modeling as described in Chapters 3 and 4 of this report. The results are summarized in Table 2-7.
Table 2-7 Sewer System Flow Estimates
Existing Flow (mgd) Future Flow (mgd) System Outfall ADWF PDWF PWWF ADWF PDWF PWWF North (to Northside and
Rabello Pump Stations) 17.7 23.6 40.8 21.2 28.7 43.1a
East (to San Jose Trimble
Road trunk sewer) 6.0 8.7 13.2 6.9 10.0 14.1
Total 24 32 54 28 38 57
Note: ADWF and PDWF represent a non-rainfall wintertime condition and include groundwater infiltration.
PWWF represents a 10-year frequency design storm.
(a) Assumes peak flow from Cupertino Sanitary District does not increase above its contracted maximum capacity of 13.8 mgd.
Hydraulic Model Development
Chapter 3
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 3 Hydraulic Model Development May 2007 3-1
Chapter 3 Hydraulic Model Development
The City, in conjunction with RMC, selected DHI’s MIKE URBAN™ with EPA SWMM 5 as the software to be used for the Sewer System Capacity Assessment. EPA SWMM 5 is the latest version of the U.S. EPA’s public domain Storm Water Management Model, which provides a fully dynamic solution for modeling storm water and sanitary sewer systems. MIKE URBAN is an ArcGIS-based model interface that provides the user environment for building and running the model and viewing model results. RMC also utilized another modeling program, InfoWorks™, to help in model construction and validation. The process of developing the model for use in the capacity assessment is described below.
3.1 Modeled System
The hydraulic model developed for the City’s Sewer System Capacity Assessment represents the trunk sewer system, the network of larger diameter pipes that comprises the “backbone” of the system. The wastewater is conveyed from the City to the San Jose/Santa Clara Water Pollution Control Plant (SJ/SC WPCP) at two locations: at the northeast corner of the City just east of Lafayette Street, where flow is pumped via the Northside and Rabello Pump Stations and force mains to the WPCP; and on the eastern side of the City east of De La Cruz Boulevard and Highway 101, where flow discharges by gravity into a 48-inch sewer in Trimble Road that conveys the flow to the City of San Jose’s interceptor in Zanker Road. The City also receives flows from the Cupertino Sanitary District (CuSD), which discharge into the Santa Clara sewer system on Homestead Road at Swallow Drive.
The City’s wastewater collection system includes a total of approximately 270 miles of sewer pipelines, of which approximately 28 percent, or 76 miles, are included in the modeled system. The modeled network includes almost all of the 15-inch and larger pipes, about 40 percent of the 10- and 12-inch pipes, and a few 6- and 8-inch pipes. The modeled system also includes four of the system’s six wastewater pump stations: Westside, Primavera, Tasman, and De La Cruz. The Northside and Rabello Pump Stations are not explicitly modeled, as their downstream hydraulic control points are governed by the downstream force mains and hydraulic gradeline at the WPCP. Rather, the northern outlet of the model is located at the junction manhole (S114-19) just upstream of the Rabello Pump Station. The modeled network is shown in Figure 3-1.
3.2 Model Network Construction and Validation
Network data for the model were provided by the City in the form of AutoCAD mapping and Excel files with manhole and pipe attribute data (manhole coordinates and rim elevations; pipe diameters, lengths, and invert elevations). Through a multi-step process, the AutoCAD file and attribute data were imported into ArcGIS to create GIS datasets of all of the pipes and manholes in the City’s system. The pipes and manholes to be included in the modeled network, described previously, were then extracted out of those datasets. The GIS files of the modeled pipes and manholes formed the basis for model construction and validation; these files were imported into the modeling environment in InfoWorks and subsequently into MIKE URBAN.
The model construction and validation process included the following steps:
▪ The modeled network was checked for connectivity, i.e., verifying that correct upstream/downstream manholes were identified for each pipe and there were no missing links in the network. ▪ Profiles were plotted for each series of pipe segments in the modeled network to visually check for missing or suspect data. Examples of missing or suspect data included missing rim or invert elevations, negative pipe slopes, or abrupt steps up or down in pipe inverts. Where appropriate, missing or suspect data were interpolated, or verification in the form of additional survey information or as-built drawings were requested from the City.
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Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
Scott Blvd.
Machado Ave.
Monroe St.
Calabazas Blvd.
Chromite Dr. U.P.R.R.
Walsh Ave.
Central Expwy.
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Modeled Pump Stations
Pump Stations Not in Model
Modeled Trunk Sewers
Sewer Mains
Parcels
Modeled System
Figure 3-1
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 3 Hydraulic Model Development May 2007 3-3
▪ As-built information was used to manually input details for each of the 22 inverted siphons in the modeled network. Dummy nodes were created as needed for the siphon angle points so that the three “legs” of the siphon (downward, horizontal, and upward) could be represented explicitly. ▪ As-built information was used to manually input details on the modeled pump stations. Information required included wet well elevations and dimensions, number of pumps, pump capacities, on/off levels, and discharge curves.
▪ Flow splits (manholes with more than one outlet pipe) were identified for further verification of outlet pipe elevations and/or the existence of weir overflows or other control structures. Field verification and/or as-built drawings were requested from the City as needed. Two structures in particular, the diversion structure at manhole S20-10 and the “flume” structure at manhole S65-30 required special investigations and model configurations.
3.3 Development of Model Loads
Flows are loaded into the model at “load manholes,” each of which represents the point where flows from unmodeled sewers discharge into the modeled network. The unmodeled sewers were grouped into sewer subbasins, each with a unique load manhole in the network. Approximately 175 sewer subbasins were delineated for defining the model loads. The subbasins and load manholes are shown in Figure 3-2.
3.3.1 Base Wastewater Loads
The City’s water billing data and recycled water discharge data from December 2005 to March 2006 were used to develop existing loads to the hydraulic model. The billing data provided by the City was compiled into a database, with each billing record (account) associated with its Santa Clara County Assessor’s Parcel Number (APN). Since many of the water billing records contained incorrect APNs or no APN at all, an extensive process was used to acquire these APNs from street address cross reference tables and other information supplied by the City. Water usage for multiple water accounts associated with the same parcel were added together. The average water use by parcel was then determined by averaging the monthly use for the four winter months (December through March). Winter water use is considered a reasonable approximation of wastewater flow because outdoor water use (irrigation) during the wintertime is minimal.
The water billing records were then linked to the City’s parcel GIS file. Each of the parcels was associated with the appropriate sewer subbasin. Finally, the total average base wastewater flow per sewer subbasin was computed by adding the flows (water use) for all parcels contained with the subbasin. Each subbasin was also characterized based on its predominant land use type (residential, commercial, or industrial) in order to apply an appropriate diurnal wastewater pattern to simulate the flows in the model.
Flows from large dischargers were removed from the cumulative sewer subbasin flow and added to the model as point loads at specific locations in the modeled system. As noted in Chapter 2, model loads for large users were based on average winter flow.
3.3.2 I/I Loads
GWI and RDI/I flows were also loaded to the model by subbasin by associating each subbasin with a flow meter area. The flow meter areas are shown in Figure 3-3. For each subbasin, the total sewered area (i.e., area that potentially contributes I/I) was determined by summing the acreage of non-open space land uses in the subbasin. Non-open space land uses include residential, commercial, industrial, and institutional uses, but do not include parks, drainage channels, and large roadways such as freeways. I/I flows for each subbasin were computed in the model by applying the appropriate meter area GWI and RDI/I parameters (determined during the model calibration process described below) to the sewered area of the subbasin.
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Modeled Trunk Sewers
Subbasin Load Manholes
Sewer Subbasins
Parcels
Subbasins and Load
Manholes
Figure 3-2
Machado Ave.
Monroe St. Chromite Dr. U.P.R.R.
Walsh Ave.
Central Expwy.
Scott Blvd.
Calabazas Blvd.
(This page intentionally left blank)
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
M_01
M_04
M_11
M_02
M_14
M_10
M_03
M_06
M_17
M_21
M_18
M_20
M_05
M_16
M_08 M_07
M_12
M_15
M_22
M_19
M_25
M_23
M_24
M_09
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Modeled Trunk Sewers
Meter Tributary Area
Parcels
Flow Meter Areas Used for
I/I Analysis
Figure 3-3
Monroe St. Chromite Dr. U.P.R.R.
Walsh Ave.
Central Expwy.
Machado Ave.
Calabazas Blvd.
Scott Blvd.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 3 Hydraulic Model Development May 2007 3-6
3.4 Model Calibration
Model calibration is the process of comparing model-computed flows to observed (monitored) flows to verify that the model is accurately simulating flows in the sewer system. The model is calibrated for both dry and wet weather conditions.
As described in Chapter 2, a temporary flow monitoring program consisting of 26 flow meters and 3 rain gauges installed in the Santa Clara system for a period of about two months (late January through early April 2006) provided data for calibration of the hydraulic model. A flow meter schematic is shown in Figure 3-4.
3.4.1 Dry Weather Calibration
The 7-day dry period from February 4 to 10, 2006, was used as the dry weather calibration period for the model. The dry weather calibration process was used to verify BWF loads and diurnal curves, and to quantify GWI (as indicated by monitored flows that were higher than estimated BWF). The model calibration resulted in a reasonably good match of modeled to metered flow at most locations, but some significant differences at others. These differences may be due to inaccuracies in the meter data, in water use loadings, or in the configuration of the system (e.g., upstream flow splits). The calibration process did result in further investigation and adjustments to several flow split locations in the model. Every effort was made to resolve as many of the calibration differences as possible. As shown in Table 3-1, the total flows in the system, as indicated by the sum of the flows at the most downstream meters (Meters 1, 2, 3, 4, 14, and 15), were within 3 percent of the modeled flows, which provides confidence that the overall flows in the model are reasonably accurate.
Table 3-1 Comparison of Meter and Model Flow
Meter Meter Avg.
Flow (mgd)
Model Avg.
Flow (mgd)
Difference
(mgd)
Percent
Difference
1 5.45 6.06 0.61 11%
2 6.17 6.66 0.49 8%
3 1.06 0.70 -0.36 -34%
4 4.25 4.20 -0.05 -1%
14 2.15 2.23 0.08 4%
15 4.06 3.90 -0.16 -4%
Total 23.13 23.74 0.61 3%
Figure 3-5 shows example plots of model vs. metered flow for two locations in the system (Meters 1 and 15).
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 3 Hydraulic Model Development May 2007 3-7
Figure 3-4 Meter Schematic
S62-8
Outfall
Outfall
ISCO 1/2 ISCO 3
22 Flow from CuSD
25 26
24 23
21 9
10 11
8 7
1 2
3 4
5 6
12 13
20 18
19 16
17 14 15
S20-9
S20-10
gates
S20-16
S10-29
S32-68 S33-5
S22-64
S23-27
S32-101
S93-53 S93-52
S73-29
S52-5
S41-113 &
S41-104
S42-104
S53-34
S68-15
S65-30
flume
S64-32
S64-46
Legend
24 S20-16
Flow Meter
Modeled flow split and node ID
Flow path
Alternate flow path
S10-29
S62-8
Outfall
Outfall
ISCO 1/2 ISCO 3
22 Flow from CuSD
25 26
24 23
21 9
10 11
8 7
1 2
3 4
5 6
12 13
20 18
19 16
17 14 15
S20-9
S20-10
gates
S20-16
S10-29
S32-68 S33-5
S22-64
S23-27
S32-101
S93-53 S93-52
S73-29
S52-5
S41-113 &
S41-104
S42-104
S53-34
S68-15
S65-30
flume
S64-32
S64-46
Legend
24 S20-16
Flow Meter
Modeled flow split and node ID
Flow path
Alternate flow path
S10-29
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 3 Hydraulic Model Development May 2007 3-8
Figure 3-5 Example Dry Weather Calibration Plots
Meter/Model Comparison at Meter 1
0 2
4 6
8 10
12 14
16 2/4 2/5 2/6 2/7 2/8 2/9 2/10 2/11
Date
Flow (mgd)
Model Meter
Meter/Model Comparison at Meter 15
0 1
2 3
4 5
6 7
8 9
10 2/4 2/5 2/6 2/7 2/8 2/9 2/10 2/11
Date
Flow (mgd)
Model Meter
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 3 Hydraulic Model Development May 2007 3-9
3.4.2 Wet Weather Calibration
Two of the larger storm events from the 2006 monitoring period, February 27 and March 5-6, were used for wet weather calibration. In general, the response to rainfall in the Santa Clara system is relatively small, as evidenced by the relatively low peak flow response to the rainfall events. As described in Chapter 2, RDI/I response to rainfall events was quantified in terms of three sets of triangular unit hydrograph parameters that represent the volume percentage of rainfall that enters the system as RDI/I and the shape of the RDI/I hydrograph as a function of each hour of rainfall. Through the wet weather calibration process, RDI/I hydrograph parameters were developed for each meter area. Additionally, wet weather GWI, as evidenced by elevated flows following the rainfall events, was determined for some areas.
Figure 3-6 presents some wet weather calibration plots for the same meters as shown in Figure 3-5.
Table 3-2 lists the GWI rates that were used for the dry and wet weather calibration by flow meter area and the RDI/I “R values” (percentages of rainfall) for each area.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 3 Hydraulic Model Development May 2007 3-10
Figure 3-6 Example Wet Weather Calibration Plots
Meter/Model Comparison at Meter 1
0 2
4 6
8 10
12 14
16 3/4 3/5 3/6 3/7 3/8 3/9 3/10 3/11
Date
Flow (mgd)
0.00 0.05
0.10 0.15
0.20 Rainfall per 15-minute Interval (in.)
Rain Gauge 1 Model Meter
Meter/Model Comparison at Meter 15
0 1
2 3
4 5
6 7
8 9
10 3/4 3/5 3/6 3/7 3/8 3/9 3/10 3/11
Date
Flow (mgd)
0.00 0.05
0.10 0.15
0.20 Rainfall per 15-min Interval (in.)
Rain Gauge 2 Model Meter
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 3 Hydraulic Model Development May 2007 3-11
Table 3-2 GWI and RDI/I Parameters by Meter Area
Meter Areaa
Dry
Weather
GWIb
(gpd/acre)
Wet
Weather
GWIc
(gpd/acre)
R1 RDI/I
Vol. (%)
(2 hrs. to
peak)
R2 RDI/I
Vol. (%)
(6 hrs. to
peak)
R3 RDI/I
Vol. (%)
(12 hrs. to
peak)
M_01 0 0 0.5 0.8 0.8
M_02 0 0 0.5 0.8 0.8
M_03 0 0 0.6 0.1 0.1
M_04 500 1,300 0.6 0.1 0.1
M_05 700 1,000 0.6 0.1 0.1
M_06 0 0 0.6 0.1 0.1
M_07 1,900 1,900 0.3 0.5 0.5
M_08 0 0 0.3 0.5 0.5
M_09 0 0 0.6 0.1 0.1
M_10 0 0 0.6 0.1 0.1
M_11 1,600 2,300 0.9 1.7 6.0
M_12 0 0 0.9 1.0 0.5
M_14 0 0 0.6 0.1 0.1
M_15 300 700 1.0 0.2 0.2
M_16 900 1,600 1.0 0.2 0.2
M_17 200 200 0.6 0.1 0.1
M_18 0 0 0.8 1.0 0.1
M_19 0 0 0.3 0.1 0.1
M_20 0 0 0.6 0.1 0.1
M_21 0 0 0.6 0.1 0.1
M_22 0 0 0.6 0.1 0.1
M_23 0 0 0.6 0.1 0.1
M_24 0 0 0.6 0.1 0.1
M_25 0 0 0.6 0.1 0.1
CuSD 0 0 0.5 0.2 0.4
(a) See Figure 3-3.
(b) Represents GWI during non-rainfall periods (e.g., early to mid-February) of the 2006 flow monitoring period.
(c) Represents GWI immediately following rainfall events. (This page intentionally left blank)
Capacity Analysis
Chapter 4
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 4 Capacity Analysis May 2007 4-1
Chapter 4 Capacity Analysis
This chapter describes the hydraulic analysis and design criteria used to evaluate system performance and size capacity relief projects, the capacity deficiencies based on the results of model runs, and preliminary solutions to identified capacity deficiencies.
4.1 Hydraulic Analysis and Design Criteria
Hydraulic analysis criteria define the conditions under which an existing component of the sewer system is considered to be deficient in capacity. As discussed in Chapter 2, these conditions are based on the design flow and performance criteria established for the system. In the case of Santa Clara, it was recommended that the trunk sewer system be evaluated with respect to its ability to convey peak flows from a 10-year design storm at service area buildout under a peak base wastewater flow condition. Based on discussions with City staff, it was also recommended that a performance criterion of no surcharge (or, more practically, minimal surcharge, e.g., no more than about one foot of surcharge if the sewer is reasonably deep) be used to identify capacity-deficient sewers.
Hydraulic analysis criteria may different from the hydraulic design criteria used to size new or relief system facilities. Hydraulic design criteria needed for sewer system capacity planning include pipe friction factor, minimum pipe diameter and depth, maximum allowable flow depth to diameter ratio (d/D), and minimum and maximum pipe slopes and velocities. Table 4-1 presents the recommended hydraulic design criteria for the Santa Clara sewer system capacity assessment. These criteria are consistent with the City’s current sanitary sewer design criteria.
Table 4-1 Hydraulic Design Criteria
Criterion Description Value
Manning’s ‘n’ Pipe friction factor 0.013
Pipe Diameter
(gravity sewers) Minimum
8 inches in residential areas, 10 inches
in commercial areas, 12 inches in
industrial areas
Pipe Depth Minimum cover over pipe 6 feet
Design Pipe Capacity Pipe capacity at peak design wet
weather flow 0.75 d/D for new or relief sewers
Minimum (pipe full or half full) 2 feet/second
Velocity
Maximum (at peak design flow) 10 feet/second
Minimum Sufficient to obtain minimum velocity
Pipe slope
Maximum Less than slope that would produce
maximum velocity
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 4 Capacity Analysis May 2007 4-2
4.2 Capacity Analysis Results
The results of model runs for future peak dry weather flow (PDWF) and design storm peak wet weather flow (PWWF) scenarios are shown in Figure 4-1 and Figure 4-2, respectively. The figures show pipes that are predicted to surcharge due to capacity deficiency or backwater from a downstream capacity deficiency. Note that the results shown reflect an “unrelieved” system, meaning that peak flows are dampened out in pipes that are under heavy surcharge due to backwater from downstream constrictions, and the true peak flows cannot be determined until the downstream capacity deficiencies are relieved.
Therefore, the data shown for percent full capacity are only approximations of system performance.
The majority of the predicted future capacity deficiencies in the system are located on the west side of the City along the 27- through 36-inch trunk sewer in Great America Parkway and Bowers Avenue and extending upstream into the smaller trunk sewers in Chromite Drive and Machado Avenue). There are also additional areas of predicted capacity deficiencies in portions of Calabazas Boulevard north of El Camino Real (ECR), ECR east and west of Calabazas Boulevard, Machado Avenue and Nobili Avenue west of Calabazas Boulevard, Monroe Street west of Chromite Drive, Scott Boulevard north of Saratoga Avenue, and Park Avenue south of Bellomy Street.
Using the model software, hydraulic profiles were generated for all areas of the system identified as being surcharged under the future design PWWF scenario. The profiles were reviewed to identify where relief capacity would be required to eliminate surcharged conditions.
It should be noted that a number of capacity deficiencies are identified in the area of the system tributary to the 18-inch trunk sewer in Chromite Drive west of Bowers Avenue (area designated as M_11 in Figure 3-3). This area is roughly bounded by Monroe Avenue and Chromite Drive on the north, ECR on the south, Bowers Avenue on the east, and the city limits on the west. The flow data from Meter 11 showed a very high volume, delayed response to rainfall, as indicated by the high values for R2 and R3 for this meter in Table 3-2. When applied to the 10-year design storm rainfall, these parameters produce a high peak response several hours after the peak of the storm. It is possible that the calibration parameters, which reasonably approximate the observed flow response to the smaller observed rainfall events in the 2006 flow monitoring period, may overestimate the response for a larger, more intense rainfall event like the 10-year design storm. Therefore, the City should consider conducting further wet weather flow monitoring in this area to verify RDI/I response prior to the design of capacity improvements.
4.2.1 Cupertino Sanitary District Flows
Based on preliminary model runs for future conditions, the projected PWWF from CuSD was estimated to be about 16 mgd. This exceeds CuSD’s contracted maximum capacity of 13.8 mgd in the Santa Clara system. Model runs were also conducted assuming no future growth in CuSD, which resulted in a peak flow of 13.9 mgd, or approximately equal to the contract capacity. Therefore, for purposes of the capacity assessment presented in this report, the maximum contract flow of 13.8 mgd was assumed for CuSD.
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Parcels
Modeled Trunk Sewers
Percent of Full Pipe Capacity
100 - 150
> 150
Surcharged due to Backwater
Model Results
Future PDWF
Figure 4-1
Scott Blvd.
Machado Ave.
Monroe St.
Calabazas Blvd.
Chromite Dr. U.P.R.R.
Walsh Ave.
Central Expwy.
(This page intentionally left blank)
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Surcharged due to Backwater
Modeled Trunk Sewers
Percent of Full Pipe Capacity
100 - 150
> 150
Parcels
Model Results
Future PWWF
Figure 4-2
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 4 Capacity Analysis May 2007 4-5
4.3 Preliminary Solutions to Capacity Deficiencies
Based on the model results and hydraulic profiles, the identified capacity-deficient locations were further reviewed to determine if they should be recommended for capacity improvement. The criterion used to make this determination was that the capacity deficiency results in at least one foot of surcharge above pipe crown, or less than five feet of freeboard under the design storm PWWF condition. This criterion allows for flexibility to eliminate the need to provide potentially expensive capacity relief projects for barely surcharged sewers.
Based on the identified capacity deficiencies, the sizes of required replacement sewers to handle the predicted future PWWF were determined. The model was then re-run with the upsized pipes to confirm that they would resolve the predicted surcharge. The development of relief solutions was an iterative process of gradually upsizing needed pipes to eliminate any significant surcharge in the system under the design peak flow condition.
The required improvements were refined by determining parallel pipe sizes that would be equivalent to pipe replacement for larger diameter sewers requiring capacity relief (the parallel pipe sizes were estimated based on model flows and existing pipe slopes). Parallel pipes were considered an alternative to replacement for trunk sewers with required diameters of 21 inches and larger. Replacement pipes were generally assumed for smaller diameter sewers. During project refinement, other factors such as constructability issues, or the need to rehabilitate or replace a pipe that may be nearing the end of its useful life, would also be taken into consideration in determining whether to parallel or replace a capacity deficient sewer.
The preliminary capacity solutions are listed in Table 4-2 and shown in Figure 4-3. Note that a capacity deficiency (identified as Project 3) was initially identified on the 24-inch Calabazas Trunk Sewer based on the initial estimate of 16 mgd future flow from CuSD. However, if CuSD flows do not exceed the
13.8 mgd contract capacity, the project would not be needed. Therefore, this project was eliminated from consideration and is not shown in Table 4-2 or Figure 4-3.
The identified projects represent preliminary solutions to the identified capacity deficiencies in the Santa Clara trunk sewer system. In the next chapter of the report, other alternatives for addressing these capacity deficiencies, including possible diversions to other trunk sewers with available capacity, or alternative relief sewer alignments that may be more cost effective to construct, are developed and evaluated in order to develop more definitive estimates for the City’s long-term Capital Improvement Program for the sanitary sewer system.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 4 Capacity Analysis May 2007 4-6
Table 4-2 Capacity Deficiencies and Preliminary Solutions Project
No. Location US MH DS MH Length (ft.)
Design
Flow
(mgd)
Exist.
Dia. (in.)
Req'd.
Dia. (in.)
Parallel
Dia. (in.)
1A
Great America Pkwy. from
Mission College Blvd. to Hetch
Hetch crossing
S83-12 S93-57 1,900 23 36 39 21
1B
Great America Pkwy. from
north side of US 101 to Mission
College Blvd.
S73-1 S83-12 1,800 22 33 39 21
2A Bowers Ave. from Kifer Rd. to
north side of US 101 S63-20 S73-1 5,000 20 30-33 39 21
2B Bowers Ave. from Chromite Dr.
to Kifer Rd. S53-34 S63-20 2,600 19 27 33 21
4A
Chromite Dr. and Monroe St.
from Machado Ave. to west of
Bowers Ave.
S52-80 S53-41 2,200 5.0-6.9 18 24-27 18-21
4B Machado Ave. from Calabazas
Blvd. to Monroe St. S52-103 S52-80 1,500 4.1 15 21 15
5 Monroe St. from Fordham Dr.
to Chromite Dr. S51-22 S52-65 2,500 0.96 10
8(siphon)
12 10(siphon) --
6 Nobili Ave. and Machado Ave.
from Flora Vista Ave. to
Calabazas Blvd.
S41-53 S52-101 3,100 2.2-3.5 10-15 15-18 --
7 Calabazas Blvd. from El
Camino Real to Cabrillo Ave. S42-106 S42-30 2,400 0.47 8 10 -- 8A El Camino Real from Pomeroy
Ave. to Bowers Ave. S42-121 S33-5 2,600 1.2 10
6(siphon)
15 8/10(siphon) --
8B El Camino Real from Flora
Vista Ave. to Pomeroy Ave. S41-113 S42-121 1,800 1.0 10 12 -- 9 Scott Blvd. from Serra Ave. to
Homestead Rd. S25-37 S35-98 800 0.56 8 10 --
10 Park Ave. south of Bellomy St. S38-75 S38-66 250 0.84 10 12 -- (This page intentionally left blank)
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
7 5
2A
2B
1B
8B
4A
9 4B
8A
10 6
1A
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Preliminary Capacity Improvements
Modeled Trunk Sewers
Parcels
Preliminary Capacity
Improvements
Figure 4-3
Monroe St.
Machado Ave.
Chromite Dr. U.P.R.R.
Central Expwy.
Walsh Ave.
Calabazas Blvd.
Scott Blvd.
(This page intentionally left blank)
Capacity Improvement Projects
Chapter 5
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 5 Capacity Improvement Projects May 2007 5-1
Chapter 5 Capacity Improvement Projects
This section summarizes the improvement projects recommended for Santa Clara’s wastewater collection system. Recommended improvements were developed from the results of hydraulic modeling of the trunk sewer system for predicted future flow conditions, as described in Chapter 4. This section discusses the projects, including alternative projects, needed to address potential capacity deficiencies in the existing trunk sewer system.
5.1 Potential Flow Diversion Alternatives
The first step in developing project alternatives was to identify potential flow diversions that could possibly relieve capacity deficiencies without the need for relief sewers, or by significantly reducing the length of needed relief sewers. The following potential flow diversions were identified:
Divert a portion of the flow from the east trunk sewer to the west trunk sewer in Great America Parkway. This diversion could potentially eliminate the need for Projects 1A and/or 1B. Divert flow from the south sewer in El Camino Real (ECR) into the 24-inch trunk sewer that runs along the east side Calabazas Boulevard. This diversion would relieve the capacity deficiency in the south sewer in ECR, which causes flow to back up into the north sewer and then flow north into the 8-inch sewer located on the west side of Calabazas Boulevard. The diversion could be accomplished by diverting flow from the south sewer in ECR into the 24-inch Calabazas trunk sewer just east of Calabazas Creek. This diversion could potentially eliminate the need for Project 7 and Project 8A, and reduce the flow to Projects 4B and 4A.
Divert flow from the sewer in Machado Avenue west of Calabazas Boulevard into the 24-inch Calabazas trunk sewer. This diversion could potentially eliminate the need for or reduce the required sizes of Projects 4B and 4A.
Divert flow from the sewer in Monroe Avenue west of Calabazas Creek into the 24-inch Calabazas trunk sewer. This diversion could potentially eliminate the need for the portion of Project 5 east of Calabazas Creek, and reduce the size of Project 4A.
Modeling indicated that diversion of flow from the east to the west trunk sewer in Great America Parkway would not be effective in eliminating the need for capacity relief for that area of the system. A possible connection between manhole S83-18 on the east side of Great America Parkway and S83-17 on the west side of Great America Parkway was evaluated as a potential alternative. However, since the west pipe was higher in elevation than the east pipe a cross connection to relieve the surcharged east pipe is not feasible. The lack of available capacity in both of these pipes further downstream makes the idea of an intertie along Great America Parkway even less feasible.
Modeling of the potential flow diversions to the Calabazas trunk sewer determined that the diversion at ECR and Calabazas Creek could eliminate the need for Project 7 and the portion of Project 8B east of Calabazas Creek. However, the amount of capacity available further downstream in the Calabazas trunk sewer is limited to approximately 1 mgd based on the critical pipe segment between Kifer Road and Scott Boulevard (MHs S62-37 to S72-20). Any additional diversions (e.g., at Machado or Monroe) would result in too much flow in the Calabazas trunk sewer. Furthermore, a diversion at Machado does not appear to be hydraulically feasible because there is insufficient elevation difference between the Machado and Calabazas sewers. Therefore, only the diversion at ECR to the Calabazas trunk sewer was carried forward as a feasible alternative.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 5 Capacity Improvement Projects May 2007 5-2
5.2 Potential Diversions to New Sewers
The second step in the alternatives analysis process was to identify locations where flows could be diverted to new trunk sewers that could be less difficult or less costly to construct than paralleling or replacing capacity deficient sewers in the same alignment. The following potential diversions to new sewers were identified:
Divert flow from the Bowers Avenue trunk sewer into a new trunk sewer that would convey flow to the eastern side of the system and ultimately to the system outfall in Trimble Road. This diversion could potentially eliminate the need for Projects 1 and 2. Divert flow from the south sewer in ECR into a new sewer in Flora Vista Avenue that would convey flow to Project 6 in Nobili Avenue. This diversion and new sewer would eliminate Project 8B and the need for construction in ECR, but Project 6, 4B and 4A would likely need to be increased in size.
Examination of the model results determined that the eastern portion of the trunk sewer system has excess capacity downstream (east) of Lafayette Street, where the trunk sewer in Central Expressway increases in size to 27 inches and then to 48 inches at De La Cruz Boulevard. Therefore, constructing a new trunk sewer from Bowers Avenue to Central Expressway east of Lafayette to divert flow from the western to the eastern part of the system could potentially reduce the flow in the Bowers Avenue and Great America Parkway trunk sewers sufficiently enough to eliminate the need for capacity relief. In order to ensure adequate grade between the flow diversion point on Bowers Avenue to the connection point to the existing system at Central Expressway, flow would need to be diverted from the existing 18-inch sewer in Chromite Drive just west of Bowers Avenue, which is about 5 feet higher than the Bowers Avenue trunk.
Modeling of this alternative indicates that up to 3.5 mgd could be diverted, which would be sufficient to eliminate the need for capacity relief for the Bowers Avenue/Great America Parkway trunk sewer.
Therefore, a potential new west-to-east trunk sewer was carried forward as a feasible alternative.
The potential diversion of flow into a new sewer in Flora Vista Avenue is also feasible. However, this alignment would be longer than the project in ECR, would require extensive construction through residential neighborhoods, and would ultimately increase the flow to the sewers in Machado Avenue, Chromite Drive, and Bowers Avenue. Therefore, although this alternative reduces the amount of construction on ECR, it does not offer any significant advantage over the preliminary capacity solution (Project 8B).
5.3 Construction Considerations
To further develop the proposed capacity improvement projects, field visits were conducted to evaluate the proposed project alignments, identify feasible pipeline corridors, and assess potential constructability issues. Utility maps were also obtained to identify potential conflicts with major utilities (e.g., storm drains, large water or recycled water mains) in the proposed project corridors. Based on these investigations, the proposed project alignments and construction methods were refined, as described below. In general, for relief projects to be constructed in the same alignment as existing capacitydeficient trunk sewers, it was assumed that the existing pipeline would be replaced rather than paralleled.
This provides a more conservative estimate, appropriate for the planning phase of these projects. For those projects in which the existing sewer is recommended for replacement with a new sewer of one or two pipe diameters larger, however, pipe bursting could also be considered as an alternative to remove and replace.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 5 Capacity Improvement Projects May 2007 5-3
5.4 Capacity Relief Projects
Table 5-1 summarizes the recommended projects. The locations of the proposed projects are shown in Figure 5-1 and described in the paragraphs below.
Table 5-1 Recommended Capacity Improvement Projects
Project
No.a Location US MH DS MH Length
(ft.)
Exist.
Dia. (in.)
Req'd. Dia.
(in.)b
1 Augustine Dr., Lakeside Dr., crossing of U.S.
101, Mission College Boulevard, Great
America Pkwy. from Bowers Ave. to south of
Hetch Hetchy ROW
S73-20 S93-57 7,200 33-36 21 (P)
2 Chromite Dr., Alhambra Dr., Bracher Park,
crossing of UPRR, Bowers Ave. from Bowers
Ave. to Augustine Dr.
S53-34 S73-20 6,200 27-33 21 (P)
West-toEast
Trunkc
Chromite Dr., Alhambra Dr., Bracher Park,
crossing of UPRR, Walsh Ave., Lafayette,
Lafayette St., Central Expwy. From Bowers Dr.
to UPRR
S53-41 S67-18 12,200 NA 24
4A Monroe St. and Chromite Dr. from Machado
Ave. to west of Bowers Ave. S52-80 S53-41 2,200 18 24-27 (R) 4B Machado Ave. from Calabazas Blvd. to
Monroe St. S52-103 S52-80 1,500 15 21 (R)
5 Monroe St. from Fordham Dr. to Chromite Dr. S51-22 S52-65 2,500 10 8(siphon)
12 (R)
8(siphon) (P)
6 Nobili Ave. and Machado Ave. from Flora Vista
Ave. to Calabazas Blvd. S41-53 S52-101 3,100 10-15 15-18 (R) 8 El Camino Real from Flora Vista Ave. to
Calabazas Blvd. S41-113 S32-5 2,600 10 12-15 (R)
9 Scott Blvd. from Serra Ave. to Homestead Rd. S25-37 S35-98 800 8 10 (R) 10 Park Ave. south of Bellomy St. S38-75 S38-66 250 10 12 (R) (a) P = parallel sewer; R = remove and replace
(b) Alternative to Projects 1 and 2.
5.4.1 Projects 1 and 2 – Bowers Ave, Mission College Blvd and Great America Pkwy These projects would provide capacity relief for the trunk sewer in Bowers Avenue from Chromite Drive to Highway 101 and the east trunk sewer in Great America Parkway from Highway 101 to just south of the Hetch Hetchy right-of-way. Crossing the Union Pacific Railroad (UPRR) and Highway 101 present particular challenges for this alignment, as well as dealing with the heavy traffic along the entire pipeline alignment. Furthermore, there are several large-diameter utilities in the area of Projects 1 and 2.
The proposed project would consist of a parallel 21-inch pipeline to provide capacity relief along this alignment. The majority of the pipeline could be constructed by open trench methods. Because of the need to cross the UPRR (where Bowers Avenue is depressed below grade at the railroad crossing) and Highway 101, and because portions of the existing trunk sewer are located in utility easements that contain other sewer and storm drain pipelines, the new sewer alignment could not exactly parallel the existing trunk sewer. Therefore, a new alignment was developed to facilitate the UPRR and Highway 101 crossings, as well as to keep the pipeline in the public right-of-way as much as possible. (This page intentionally left blank)
Great America
Theme Park
Mission
College
Santa Clara
University
El Camino Real
US 101
US 101
Montague Expwy.
San Tomas Expwy.
Lawrence Expwy.
Lafayette St.
Lafayette St.
De La Cruz Blvd.
Stevens Creek Blvd. Bowers Ave. Great America Pkwy. Kiely Blvd.
Homestead Rd.
Hwy 237
Trimble Rd.
5 Scott Blvd.
Machado Ave.
Monroe St.
Calabazas Blvd.
Chromite Dr.
U.P.R.R.
Walsh Ave.
Central Expwy.
6 2
1 West-to-East
Trunk Alternative
4A
8 9
4B
10 ECR
Diversion
0 0.5 1
Miles
City of Santa Clara
Sanitary Sewer Capacity
Assessment
Legend
Study Area Boundary / City Limit
Capacity Improvement Projects
Modeled Trunk Sewers
Parcels
Recommended Capacity
Improvement Projects
Figure 5-1
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 5 Capacity Improvement Projects May 2007 5-5
Starting at the intersection of Bowers Avenue and Chromite Drive (manhole S53-34), the pipeline would extend eastward along Chromite Drive to Alhambra Drive and then north to Bracher Park. From the south end of Bracher Park, the pipeline would be tunneled roughly 850 feet underneath the park and the UPRR and underneath a private parking lot, and would then be tunneled approximately 500 feet roughly parallel to the northern edge of the City’s power substation property, terminating at approximately the intersection of Bowers Avenue and Mead Avenue. Temporary and permanent easements would be required for construction in the properties adjacent to the City’s power substation.
Extending north from Mead Avenue, the pipeline could be aligned along the east side of Bowers Avenue to Central Expressway. Trenchless construction methods would be used to cross Central Expressway.
The pipeline would continue north on the west side of Bowers until turning west on Augustine Drive. At Lakeside Drive it would turn north again. Junction structures would be needed where the proposed pipeline crosses the alignment of the existing 21-inch and 30-inch sewers in Lakeside Drive. From near manhole S73-6 on Lakeside Drive, the pipeline would be tunneled approximately 500 feet across Highway 101 to Mission College Boulevard, parallel to the existing 30-inch sewer crossing.
The pipeline would extend north and then east on Mission College Boulevard to Great America Parkway.
It is assumed that an inverted siphon would be used to cross under the existing 33- and 36-inch trunk sewers and the 54-inch storm drain located in the utility easement that crosses the east-west segment of Mission College Boulevard. From Mission College Boulevard, the pipeline would follow the east side of Great America Parkway, terminating at manhole S93-57.
5.4.2 New West-to-East Trunk Sewer Alternative
As described above, a new west-to-east trunk sewer would be a possible alternative to Projects 1 and 2.
The project would involve intercepting a portion of the flow from the sewer in Chromite Drive just west of Bowers Avenue, which currently discharges to the Bowers Avenue trunk sewer, and diverting it into a new 24-inch sewer that would run in a general west-to-east direction, discharging to the existing 27-inch trunk sewer in Central Parkway east of Lafayette Street. The advantage of this alignment would be avoiding the potentially difficult construction that would be required for Projects 1 and 2 (described above), as well as reducing the flow to the Northside and Rabello Pump Stations, thereby saving in pumping costs. A new west-to-east trunk sewer would also increase the overall flexibility of the system by connecting the west and east basins.
Various alignments for a west-to-east trunk sewer were evaluated using aerial mapping as well as field investigation. The most difficult challenge of the sewer alignment would be the crossing of the UPRR right-of-way. Based on field verification, the preferred alignment would be similar to that proposed for Project 2 from the intersection of Chromite Drive and Bowers Avenue, east to Alhambra Drive, and then north to Bracher Park. As in that project, the pipeline would be tunneled under Bracher Park and across the UPRR to the parking lot behind the buildings on Walsh Avenue. The new sewer would then turn east and be tunneled through the parking lot to Walsh Avenue, then continue east along Walsh Avenue. Twin 15-inch siphons would be installed across San Tomas Aquino Creek. The pipeline would also be tunneled underneath San Tomas Expressway. An inverted siphon would also need to be installed at the Scott Boulevard crossing to avoid a 42-inch storm drain.
On Walsh Avenue between Scott and Lafayette, the existing alignment of utilities makes placing a new 24-inch sewer a challenge. Roughly 1,500 feet of an existing 8-inch water pipeline may need to be moved to provide room for the new sewer pipeline. At Lafayette, the new sewer line would turn north, with a siphon needed to cross Lafayette Street at the south side of Central Expressway to cross under an existing storm drain.
Because the existing 27-inch trunk in Central Expressway at Lafayette Street is located in the center of the road, the proposed new trunk sewer would turn east and follow the southern shoulder of Central Expressway before connecting into the 27-inch line. To alleviate a potential backwater condition due to a City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 5 Capacity Improvement Projects May 2007 5-6
very flat section of pipe that crosses under the UPRR further downstream, the proposed west-to-east trunk pipeline was extended downstream to manhole S67-18.
The west-to-east trunk sewer would increase the peak design flow in the 48-inch Trimble Road trunk sewer from 14.1 to 16.7 mgd. Note that the most downstream parallel 33-inch lines in Trimble Road between North First Street and Zanker Road, where the City’s Trimble Road trunk sewer connects into the City of San Jose’s interceptors, were not included in the hydraulic model. It is assumed that these lines would have sufficient capacity to handle the increased flows. It is also assumed that the additional flow from the Trimble Road trunk sewer would have minimal impact on the flows in the interceptors in Zanker Road.
5.4.3 Projects 4A and 4B – Machado Avenue and Chromite Drive This project would provide capacity relief on Machado Avenue, Monroe Street, and Chromite Drive from Calabazas Boulevard to just west of Bowers Avenue (manholes S52-103 to S53-41). (The existing 12- inch siphon across Calabazas Creek would not need to be upsized.) The existing 15- and 18-inch sewers would need to be replaced with 21-, 24-, and 27-inch pipes. A parallel sewer could be an option; however, there is limited room in these streets for another sewer because of other utilities. Approximately 85 lower laterals and cleanouts would also need to be replaced along this alignment, in accordance with the City’s policy of replacing lower laterals whenever the main sewer is replaced. Because it is generally considered inadvisable to connect laterals to larger diameter pipelines (e.g., larger than about 18 inches), possibly a parallel 8-inch line could be installed above or adjacent to the new pipe, to which the laterals could be connected.
5.4.4 Project 5 – Monroe Street
Along Monroe Street, from Fordham Drive to Chromite Drive, approximately 2,500 feet of 10-inch sewer would be replaced with 12-inch pipe in order to increase the capacity of this sewer from manholes S51-22 to S52-65. Additionally, a parallel siphon at Calabazas Creek would be installed to increase the capacity of the existing single 8-inch siphon. It is estimated that eight lower laterals would need to be replaced as part of this project.
The portion of the project from MHs S52-51 to S52-65 could possibly be eliminated by a diversion into the 24-inch Calabazas trunk sewer. However, the model indicates that there would be limited capacity available in this pipeline once the El Camino Real Diversion is constructed, so this alternative is not recommended at this time. The diversion, or a potential partial diversion (e.g., with an overflow weir) could be considered in the future if capacity in the Calabazas trunk sewer appears to be adequate.
5.4.5 Project 6 – Nobili Avenue and Machado Avenue
This project would replace 3,100 feet of pipeline along Nobili and Machado Avenues, extending from manholes S41-53 to S52-101. The existing 10-, 12- and 15-inch sewers would be replaced with 15- and 18-inch pipe. Approximately 52 lower laterals would also need to be replaced along this alignment.
5.4.6 ECR Diversion to Calabazas Trunk Sewer
As an alternative to preliminary projects 7 and 8A, a diversion on El Camino Real can be constructed to direct flow into the 24-inch Calabazas trunk sewer. For this diversion, a new pipe would be needed to connect the sewer just downstream of the siphon on the ECR south sewer to divert the flow into the 24- inch Calabazas trunk (at approximately manhole S32-8). This diversion is not listed as a capacity improvement project in Table 5-1 because it is assumed that the connection will be coordinated with the siphon upgrade at Calabazas Creek (replacement of the existing 6-inch siphon with an 8- and 10-inch double siphon) being constructed in conjunction with the channel work being conducted by the Santa Clara Valley Water District. Only a small segment of pipe would be needed to complete this diversion, making it a cost effective alternative to preliminary projects 7 and 8A.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 5 Capacity Improvement Projects May 2007 5-7
5.4.7 Project 8 – El Camino Real
The existing 10-inch pipeline on the south side of El Camino Real between Flora Visa Avenue and Calabazas Boulevard should be upsized to 12-inch diameter from Flora Visa Avenue to Pomeroy Avenue and to 15-inch diameter from Pomeroy Avenue to Calabazas Creek. This capacity relief project would involve replacing roughly 2,600 feet of pipeline and twelve lower laterals, from manholes S41-113 to S32-5.
5.4.8 Project 9 – Scott Boulevard
This capacity upgrade project is located on Scott Boulevard from Serra Avenue to Homestead Road. It would involve replacing 800 feet of 8-inch sewer with 10-inch pipe and 14 lower laterals, from manholes S25-37 to S35-98.
5.4.9 Project 10 – Park Avenue
The 10-inch pipe on Park Avenue, south of Bellomy Street should be replaced with a 12-inch pipe in order to provide capacity relief. This project would involve 250 feet of pipeline, from manhole S38-75 to manhole S38-66, including two lower laterals.
Recommended Capital
Improvement Program
Chapter 6
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 6 Recommended Capital Improvement Program
May 2007 6-1
Chapter 6 Recommended Capital Improvement Program
This chapter presents the recommended Capital Improvement Program (CIP) for capacity improvements to the Santa Clara wastewater collection system, along with estimated project costs and proposed schedule for construction.
6.1 Estimated Cost of Proposed Sewer Improvement Projects The estimated costs of the proposed projects were refined based on more detailed quantity takeoffs and evaluation of likely construction methods and requirements. Unit cost criteria (updated to current dollars) and cost assumptions developed for the City of San Jose’s Phase I Sanitary Sewer Master Plan Capacity Assessment were used in developing the cost estimates. These criteria include baseline construction costs for gravity trunk sewers using open-cut and trenchless (e.g., microtunneling) methods, costs for lower lateral replacement for remove-and-replace projects, costs for major sewer junction structures and siphon inlet and outlet structures, and costs allowances for project mobilization/demobilization, traffic control, bypass pumping and delay factors for remove-and-replace projects, extra dewatering requirements in areas of high groundwater, and acquisition of temporary and permanent easements if needed. A 30 percent allowance for contingencies for unknown conditions was also included, as well as an allowance of 25 to 35 percent of construction cost (depending on project size) for engineering, administration, and legal costs.
Table 6-1 summarizes the cost criteria used for preparing the project cost estimates. These cost estimates are planning or conceptual level estimates, and are considered to have an estimated accuracy range of -30 to +50 percent. This level of accuracy corresponds to an “order of magnitude” or “Class 5” cost estimate as defined by the American Association of Cost Estimators. These estimates are suitable for use for budget forecasting, CIP development, and project evaluations, with the understanding that refinements to the project details and costs would be necessary as projects proceed into the design and construction phases.
Table 6-2 presents the estimated construction and capital costs for the proposed projects and major project alternatives. More detailed breakdowns of the costs for each project are included in Appendix B.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 6 Recommended Capital Improvement Program
May 2007 6-2
Table 6-1 Summary of Cost Criteria
Item Description/ Assumptions Unit Costa
Open-Cut Gravity Trunk Sewers 10" - 27" diameter, 8' - 16' depth $160 - $240/lf 36" - 49" casing $90 - $1,200/lf
Jacking/Receiving Pits $70,000/$40,000
Lower Lateral Replacement $2,000
Special Structures Junctions, siphon inlet/outlet $6,000 - $9,000 High Groundwater (north of
Highway 101)
Dewatering plus extra sheeting
and shoring
$100/lf
Bypass Pumping/Diversion 10%
Remove/Replace Delay Factor 2%
Mobilization/Demobilization 5%
Traffic Control 10%
Contingencies 30%
Temporary Easement Easement width = 80 ft $4/sq. ft.
Permanent Easement Easement width = 30 ft $25/sq. ft.
Engineering, Administration,
and Legal Costs
% of Construction Cost Total
(varies depending on magnitude
of Estimated Construction Cost)
25% - 35%
Baseline Pipeline Construction Costs
% of Baseline Construction Cost
for remove and replace projects
Construction Cost Allowances
Easement Acquisition
Site Specific Construction Costs
% of Construction Cost Subtotal
Microtunneling
(a) Based on an Engineering News Record (ENR) Construction Cost Index for the San Francisco Bay Area of 9103 (March 2007).
Table 6-2 Estimated Costs of Capacity Improvement Projects Project No.
Estimated
Construction
Cost ($)
Estimated Capital
Cost ($)
1 4,539,000 5,674,000
2 5,286,000 7,324,000
4A 1,489,000 1,861,000
4B 1,060,000 1,325,000
5 1,046,000 1,308,000
6 1,139,000 1,424,000
8 945,000 1,276,000
9 256,000 346,000
10 77,000 104,000
Total 15,837,000 20,642,000
West-to-East Alternative 9,752,000 12,906,000
Total w/West-to-East
Alternative 15,764,000 20,550,000
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 6 Recommended Capital Improvement Program
May 2007 6-3
6.2 Comparison of Major Alternatives
As described in Chapter 5, two major alternatives were evaluated for providing capacity relief for the major trunk sewers in Bowers Avenue and Great America Parkway: paralleling or replacement of those sewers, or diverting flow to a new West-to-East trunk sewer. As presented above, the two alternatives are virtually equal in terms of estimated capital cost. Other factors that should be considered in comparing these alternatives are:
Constructability. Bowers Avenue and Great America Parkway are two of the busiest roads in the City. Construction in those corridors would require extensive traffic control and potentially have significant impact on businesses in the area. The sewer alignment also has a number of significant other utilities (e.g., large storm drains). The West-to-East trunk sewer would likely have fewer traffic impacts, but could require the realignment of about 1,500 feet of water main along part of the corridor, siphon crossings under San Tomas Aquino Creek and several large storm drains, and some construction along the shoulder of busy Central Expressway. Permits and Easements. The Bowers/Great America Parkway project would require a permit from Caltrans for a new sewer crossing under Highway 101. Both projects would require crossing the UPRR west of Bowers, including obtaining a permanent sewer easement across properties adjacent to the City’s power substation on the north side of the UPRR. The West-to-East trunk would require coordination with Santa Clara Valley Water District for the crossing of San Tomas Aquino Creek.
Both projects would require permits from the County for work in or crossing Central Expressway and, in the case of the West-to-East project, San Tomas Expressway. Project Phasing/Flexibility. The Bowers/Great America Parkway project could be constructed and put into operation in phases, whereas the West-to-East project could not be used until the entire project was constructed. However, that project would provide greater overall system flexibility by linking the west and east basins by a major trunk.
Coordination with Development and Other City Projects: Current development activity on the west side of the City may provide opportunities for the City to coordinate with developers in construction of some capacity improvement projects. For example, proposed developments in the area of El Camino Real and Lawrence Expressway may construct or fund improvements, such as the El Camino Real relief sewer (Project 8), to allow those developments to move forward more quickly.
Other potential projects, either by City or other utilities, may also impact the desirability of one or the other of the major trunk system alternatives.
Long-term Cost Savings. Diverting flow from the west to the east basin could reduce the overall flows to the Rabello and Northside Pump Stations. The amount of such reduction would depend on the configuration of the flow diversion to the West-to-East trunk. A rough estimate of the reduction in average daily flow would indicate a potential annual cost savings of about $10,000 based on City’s estimate of $8,000 per mgd cost for power for pumping.
Because the estimated capital costs of the two major alternatives are nearly identical, it is recommended that the City pursue additional predesign level alignment and constructability evaluations of both alternatives before making a decision on which alternative to implement as part of the overall capacity improvement program.
6.3 Prioritization and Schedule for Proposed CIP Projects A preliminary schedule for completion of the recommended CIP projects over a five-year period has been developed based on assigning relative priorities to the proposed capacity improvements. Priorities have been based on the relative magnitude of the predicted capacity deficiencies, as well as the likely timing of City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 6 Recommended Capital Improvement Program
May 2007 6-4
developments that may impact the need for the projects. Based on these considerations, the projects have been divided into two priority groups, as listed in Table 6-3.
Table 6-3 Project Priority Groups
Project No.
Estimated
Construction
Cost ($)
Estimated Capital
Cost ($)
2 5,286,000 7,324,000
4A 1,489,000 1,861,000
8 945,000 1,276,000
Subtotal 7,720,000 10,461,000
1 4,539,000 5,674,000
4B 1,060,000 1,325,000
5 1,046,000 1,308,000
6 1,139,000 1,424,000
9 256,000 346,000
10 77,000 104,000
Subtotal 8,117,000 10,181,000
Total 15,837,000 20,642,000
West-to-East Alternativea 9,752,000 12,906,000
Total w/West-to-East
Alternative 15,764,000 20,550,000
Priority Group 1
Priority Group 2
(a) Would replace Projects 1 and 2 and be included in Priority Group 1.
For each project, a preliminary estimate of time required to implement the project has been developed, considering time required for design and construction, including obtaining necessary permits and easements. Based on the project schedules and priorities, Figure 6-1 shows a preliminary schedule for the recommended five-year capacity improvement CIP. The schedule is based on proceeding with the Bowers/Great America Parkway relief sewer, but provides for a preliminary alignment study of both this and the West-to-East trunk alternative, as recommended above. If the City decides to proceed with the West-to-East alternative in lieu of the Bowers/Great America Parkway relief, then the overall CIP schedule would need to be modified.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 6 Recommended Capital Improvement Program
May 2007 6-5
Figure 6-1 Proposed CIP Schedule
With Projects 1 and 2
Alignment Study
Project 8
Project 4A
Project 2
Project 1
Project 4B
Projects 5&6
Projects 9&10
With West-to-East Trunk Alternative
Alignment Study
Project 8
Project 4A
West-to-East Trunk
Project 4B
Projects 5&6
Projects 9&10
Planning
Design
Bid and Award
Construction
Project Year 1 Year 2 Year 3 Year 4 Year 5
Project Year 1 Year 2 Year 3 Year 4 Year 5
6.4 Implementation Recommendations
The City should begin implementation of the Capital Improvement Program recommended in this Sanitary Sewer Capacity Assessment, starting with the highest priority projects. The following items should be considered in project scheduling and design, and in future updates of the Capacity Assessment. ▪ The alignments and sizes of all recommended projects should be verified with detailed predesign analyses, including topographic surveys, geotechnical investigations, utility research, and constructability reviews.
▪ The decision to parallel or replace existing sewers should consider the physical condition and remaining useful life of the existing pipelines; the availability of pipeline corridors for new sewer construction; and operation and maintenance concerns.
▪ The hydraulic model has been developed to assist the City in performing capacity analyses and updating the Capacity Assessment in the future. The model should be kept up-to-date with any changes to existing sewer connections, development plans, and sewer system facilities. ▪ The City should periodically calibrate its permanent flow meters at the Northside and Rabello Pump Stations and on the Trimble Road trunk sewer to ensure that accurate flow information is available to track the changes in the flows in the City’s system over time. ▪ The City should conduct additional flow monitoring at key locations in the sewer system, particularly the area tributary to the Chromite/Machado trunk sewers (flow meter 11 area). Flow levels during large storm events should be compared to the peak flows simulated by the hydraulic model to verify the modeling predictions for the 10-year design storm and confirm the need for and sizing of Projects 4A, 4B, 5, and 6.
City of Santa Clara Sanitary Sewer Capacity Assessment Chapter 6 Recommended Capital Improvement Program
May 2007 6-6
▪ The City should consider additional field investigations, including smoke testing, and manhole and pipeline television inspection, in the flow meter 11 area to identify potential sources of I/I and possible opportunities for I/I reduction in this area.
▪ The City should coordinate with the Cupertino Sanitary District on flow and planning assumptions to ensure that adequate capacity exists in the Santa Clara system to handle future flows from CuSD.
The City should encourage CuSD to verify the calibration of its flow meter at Homestead Road and confirm its projections of future wastewater flows entering the Santa Clara system. ▪ The City should coordinate with the City of San Jose to ensure that its flow criteria and planning assumptions are consistent with those used by San Jose in its capacity master planning. ▪ The City should assess its connection fees and evaluate financial alternatives to fund the recommended capacity assessment CIP.
This Sanitary Sewer Capacity Assessment report is intended to be a working document to be refined and updated as additional data and new planning information becomes available. The Capacity Assessment should be updated whenever there are major changes in planning assumptions or, at a minimum, every five years.
Plots of Flow Monitoring
Data
Appendix A
Site 1 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 1
86420
201816141210
1/23 1/25 1/27 1/29 1/31 2/2 2/4 2/6 2/8 2/10 2/12 2/14 2/16 2/18 2/20 2/22 2/24 2/26 2/28 3/2 3/4 3/6 3/8 3/10 3/12 3/14 3/16 3/18 3/20 3/22 3/24 3/26 3/28 3/30 4/1 4/3 Date
Flow (mgd)
Site 2 072906.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 2
86420
201816141210
1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 3 072906.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 3
5.04.54.03.53.02.52.01.51.00.50.0 1/23 1/25 1/27 1/29 1/31 2/2 2/4 2/6 2/8 2/10 2/12 2/14 2/16 2/18 2/20 2/22 2/24 2/26 2/28 3/2 3/4 3/6 3/8 3/10 3/12 3/14 3/16 3/18 3/20 3/22 3/24 3/26 3/28 3/30 4/1 4/3 Date
Flow (mgd)
Site 4 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 4
9876543210
121110
1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 5 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 5
55443322110
1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 6 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 6
5.04.54.03.53.02.52.01.51.00.50.0 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 7 072906.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 7
86420
1816141210
1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 8 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 8
9876543210
10 1/23 1/25 1/27 1/29 1/31 2/2 2/4 2/6 2/8 2/10 2/12 2/14 2/16 2/18 2/20 2/22 2/24 2/26 2/28 3/2 3/4 3/6 3/8 3/10 3/12 3/14 3/16 3/18 3/20 3/22 3/24 3/26 3/28 3/30 4/1 4/3 4/5 Date
Flow (mgd)
Site 9 072906.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 9
9876543210
10 1/23 1/25 1/27 1/29 1/31 2/2 2/4 2/6 2/8 2/10 2/12 2/14 2/16 2/18 2/20 2/22 2/24 2/26 2/28 3/2 3/4 3/6 3/8 3/10 3/12 3/14 3/16 3/18 3/20 3/22 3/24 3/26 3/28 3/30 4/1 4/3 Date
Flow (mgd)
Site 10 061406.xls, Flow ]
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 10
86420
201816141210
1/23 1/25 1/27 1/29 1/31 2/2 2/4 2/6 2/8 2/10 2/12 2/14 2/16 2/18 2/20 2/22 2/24 2/26 2/28 3/2 3/4 3/6 3/8 3/10 3/12 3/14 3/16 3/18 3/20 3/22 3/24 3/26 3/28 3/30 4/1 4/3 Date
Flow (mgd)
Site 11 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 11
876543210
1/19 1/21 1/23 1/25 1/27 1/29 1/31 2/2 2/4 2/6 2/8 2/10 2/12 2/14 2/16 2/18 2/20 2/22 2/24 2/26 2/28 3/2 3/4 3/6 3/8 3/10 3/12 3/14 3/16 3/18 3/20 3/22 3/24 3/26 3/28 3/30 4/1 4/3 Date
Flow (mgd)
Site 12 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 12
9876543210
10 1/18 1/20 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 13 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 13
1.00.90.80.70.60.50.40.30.20.10.0 1/18 1/20 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 4/6 4/8 4/10 4/12 4/14 Date
Flow (mgd)
Site 14 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 14
9876543210
10 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 15 072906.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 15
9876543210
10 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 16 072906.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 16
55443322110
1/18 1/20 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 4/6 4/8 4/10 4/12 4/14 4/16 4/18 Date
Flow (mgd)
Site 17 081106.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 17
1.21.00.80.60.40.20.0 1/20 1/23 1/26 1/29 2/1 2/4 2/7 2/10 2/13 2/16 2/19 2/22 2/25 2/28 3/3 3/6 3/9 3/12 3/15 3/18 3/21 3/24 3/27 3/30 4/2 4/5 4/8 4/11 4/14 4/17 4/20 4/23 4/26 4/29 5/2 Date
Flow (mgd)
Site 18 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 18
4.03.53.02.52.01.51.00.50.0 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 19 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 19
3.02.52.01.51.00.50.0 1/20 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 20 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 20
2.01.81.61.41.21.00.80.60.40.20.0 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 4/6 4/8 4/10 4/12 4/14 4/16 4/18 Date
Flow (mgd)
Site 21 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 21
86420
201816141210
1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 22 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 22
2.01.81.61.41.21.00.80.60.40.20.0 1/20 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 23 072906.xls, Flow \
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 23
9876543210
10 1/20 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 24 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 24
9876543210
10 1/20 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Site 25 061406.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 25
1.00.80.60.40.20.0 1/20 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 4/6 4/8 4/10 4/12 4/14 4/16 4/18 Date
Flow (mgd)
Site 26 072906.xls, Flow
City of Santa Clara
Sanitary Sewer Flow Monitoring, Site 26
9876543210
10 1/22 1/24 1/26 1/28 1/30 2/1 2/3 2/5 2/7 2/9 2/11 2/13 2/15 2/17 2/19 2/21 2/23 2/25 2/27 3/1 3/3 3/5 3/7 3/9 3/11 3/13 3/15 3/17 3/19 3/21 3/23 3/25 3/27 3/29 3/31 4/2 4/4 Date
Flow (mgd)
Project Descriptions and
Cost Estimates
Appendix B
PROJECT ID:…………………………………………………………1
PROJECT LOCATION:………………………………………………
BRIEF PROJECT DESCRIPTION:……………………
SANITARY SEWER PLAT MAP(S):……………………………
LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:…………………………..
ALTERNATIVES:……………………………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH*
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
Augustine Dr, Lakeside Dr. and HWY 101 Crossing 21 8-16 2,300' 210 $/ft $483,000 HWY 101 (casing) 43 Microtunnel 700' 1,000 $/ft $700,000 Mission College Blvd. 21 8-16 2,900' 210 $/ft $609,000
Mission College Blvd. double 15" Siphon under utilties 49 Microtunnel 50' 1,200 $/ft $60,000 Carrier piping for 15-inch double siphon 15 Carrier pipe 100' 180 $/ft $18,000 Great America Parkway 21 8-16 2,000' 210 $/ft $420,000
Jacking Pits 2 pits $70,000 $140,000
Receiving Pits 2 pits $40,000 $80,000
Structures
Sewer Junction Structure: Lakeside and Augustine $6,000 $6,000 Sewer Junction Structure: Lakeside Drive near HWY 101 $6,000 $6,000 Siphon structures at Mission College Blvd 2 structures $6,000 $12,000 Sewer Junction Structure: Great America Pkwy. near
Patrick Henry $6,000 $6,000
Sewer Junction Structure: connection to S93-57 $6,000 $6,000
SITE SPECIFIC CONSTRUCTION COST
High Groundwater
Dewatering (North of HWY 101) 4,900' 50 $/ft $245,000
Sheeting/Shoring
Solid Shoring (North of HWY 101) 4,900' 50 $/ft $245,000 SUBTOTAL $3,036,000
Mobilization and Demobilization 5% $151,800
Traffic Control 10% $303,600
CONSTRUCTION COST SUBTOTAL $3,491,400
Contingencies 30% $1,047,420
CONSTRUCTION COST TOTAL $4,538,820
Engineering and Inspection Costs 25% $1,134,705
CAPITAL IMPROVEMENT COST TOTAL $5,673,525
ENR = 9103 (S.F. March 2007) rounded $5,674,000
* Pipe lengths include carrier pipe for siphons, double siphons and tunneled sewers. 63, 73, 83, 93
TRUNK SEWER SYSTEM PROJECT DESCRIPTION
Augustine Dr., Lakeside Dr., crossing of U.S. 101, Mission College Boulevard, Great America Pkwy. from Bowers Ave. to south of Hetch Hetchy ROW
Near MH S73-20 to MH S93-57
Install 7,200 feet of 21-inch pipeline.
New West-to-East pipeline extending from Bowers at Chromite to Central east of Lafayette.
Bowers Ave., Mission College Blvd., and Great America Pkwy. from Augustine Dr. to south of Hetch Hetchy ROW
Diameter of existing deficient pipes: 33"-36"
Caltrans permit required for crossing Hwy. 101. Best placement of new sewer in Lakeside Dr. is along the west side (to avoid 21" sewer, 12" water, and 24" storm drain). Best placement of new sewer in Mission College Blvd. is along west side (to avoid 18" storm drain and 30" and 33" sewers).
Assume siphon under 54" storm drain and 33" and 36" sewers in Mission College Blvd. west of Great America Pkwy. Best placement for new sewer is along east side of Great America Pkwy. (to avoid 66" to 72" storm drain on west side).
City of Santa Clara
Sanitary Sewer Capacity Assessment Project 1 May 2007
PROJECT ID:………………………………………………………2
PROJECT LOCATION:……………………………………………
BRIEF PROJECT DESCRIPTION:……………………
SANITARY SEWER PLAT MAP(S):……………………………
LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:…………………………..
ALTERNATIVES:……………………………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH*
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
Chromite, Alhambra, Bracher Park, easement to Bowers 21 8-16 2,300' 210 $/ft $483,000 UPRR Crossing (casing) 43 Microtunnel 1,350' 1,000 $/ft $1,350,000 Central Expressway (casing) 43 Microtunnel 600' 1,000 $/ft $600,000 Bowers Ave (Mead to Augustine) 21 8-16 3,900' 210 $/ft $819,000 Jacking Pits 2 pits $70,000 $140,000
Receiving Pits** 3 pits $40,000 $120,000
Structures
Sewer Junction Structure: Bowers and Chromite $6,000 $6,000 Sewer Junction Structure: Bowers and Walsh $6,000 $6,000 Sewer Junction Structure: Bowers and Central $6,000 $6,000 Sewer Junction Structure: Bowers and Scott $6,000 $6,000 SUBTOTAL $3,536,000
Mobilization and Demobilization 5% $176,800
Traffic Control 10% $353,600
CONSTRUCTION COST SUBTOTAL $4,066,400
Contingencies 30% $1,219,920
CONSTRUCTION COST TOTAL $5,286,320
Land Acquisition - Temporary Easement Cost
(Trenchless staging) 150' wide 150' 4 $/sf $78,750
Land Acquisition - Permanent Easement Cost
(Pipeline Alignment) 30' wide 850' 25 $/sf $637,500
Engineering and Inspection Costs 25% $1,321,580
CAPITAL IMPROVEMENT COST TOTAL $7,324,150
ENR = 9103 (S.F. March 2007) rounded $7,324,000
* Pipe lengths include carrier pipe for siphons, double siphons and tunneled sewers. ** For tunneling under UPRR to Bowers, two receiving pits and one jacking pit are needed. 53, 63
TRUNK SEWER SYSTEM PROJECT DESCRIPTION
Chromite Dr., Alhambra Dr., Bracher Park, crossing of UPRR, Bowers Ave. from Bowers Ave. to Augustine Dr.
MH S53-34 to near MH S73-20
Install 6,200 feet of 21-inch pipe.
New West-to-East pipeline extending from Bowers at Chromite to Central east of Lafayette. Alternative UPRR crossing from Park through City-owned substation not selected due to utility conflicts (this alignment might be feasible, but it is not considered best alternative).
Bowers Ave. from Chromite Dr. to Augustine Dr.
Diameter of existing deficient pipes: 27"-33"
UPRR permit required for crossing. County permit required for crossing Central Expwy. Permanent easements required through properties on Walsh and Bowers north of UPRR. Best placement for new sewer is along east side of Bowers south of Central Expwy. and along west side of Bowers north of Central Expwy (to avoid 12" water and 42" storm drain). Trenchless crossing assumed under Central Expwy.
City of Santa Clara
Sanitary Sewer Capacity Assessment Project 2 May 2007
PROJECT ID:…………………………………………………………. West-to-East Alternative PROJECT LOCATION:…………………………………………………
BRIEF PROJECT DESCRIPTION:……………………
SANITARY SEWER PLAT MAP(S):…………………………… 53, 54, 55, 56, 63, 64, 66, 67 LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:…………………………..
ALTERNATIVES:……………………………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH*
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
Chromite, Alhambra, Bracher Park, easement to Walsh 24 8-16 2,300' 220 $/ft $506,000 Walsh, Lafayette, and Central Expwy. 24 8-16 9,900' 220 $/ft $2,178,000 UPRR Crossing (casing)** 49 Microtunnel 1,350' 1,200 $/ft $1,620,000 San Tomas Aquino Creek Crossing Siphon (casing) 49 Microtunnel 200' 1,200 $/ft $240,000 San Tomas Expwy. Crossing (casing) 49 Microtunnel 400' 1,200 $/ft $480,000 Scott Blvd. siphon under street and strom drain (casing) 49 Microtunnel 300' 1,200 $/ft $360,000 Lafayette at Central siphon under storm drain (casing) 49 Microtunnel 50' 1,200 $/ft $60,000 Carrier piping for 15-inch double siphons 15 Carrier Pipe 1,100' 180 $/ft $198,000 Relocate existing waterline on Walsh due to utility conflicts 8 1,500' 150 $/ft $225,000 Jacking Pits 5 pits $70,000 $350,000
Receiving Pits 6 pits $40,000 $240,000
Structures
Sewer Junction Structure: Chromite $6,000 $6,000
Sewer Junction Structure: Walsh and Northwestern Pkwy. $6,000 $6,000 Siphon structures- San Tomas Aquino Creek 2 structures $6,000 $12,000 Sewer Junction Structure: Wash and San Tomas Expwy. $6,000 $6,000 Siphon structures- Scott Blvd 2 structures $6,000 $12,000 Siphon structures- Lafayette St. 2 structures $6,000 $12,000 Sewer Junction Structure: Central Expwy. at S67-15 $6,000 $6,000 Sewer Junction Structure: Central Expwy. at S67-18 $6,000 $6,000 SUBTOTAL $6,523,000
Mobilization and Demobilization 5% $326,150
Traffic Control 10% $652,300
CONSTRUCTION COST SUBTOTAL $7,501,450
Contingencies 30% $2,250,435
CONSTRUCTION COST TOTAL $9,751,885
Land Acquisition - Temporary Easement Cost
(Trenchless staging) 150' wide 150' 4 $/sf $78,750
Land Acquisition - Permanent Easement Cost
(Pipeline Alignment) 30' wide 850' 25 $/sf $637,500
Engineering and Inspection Costs 25% $2,437,971
CAPITAL IMPROVEMENT COST TOTAL $12,906,106
ENR = 9103 (S.F. March 2007) rounded $12,906,000
* Pipe lengths include carrier pipe for siphons, double siphons and tunneled sewers. ** For tunneling under UPRR to Walsh, two receiving pits and one jacking pit are needed.
TRUNK SEWER SYSTEM PROJECT DESCRIPTION
Chromite Dr., Alhambra Dr., Bracher Park, crossing of UPRR, Walsh Ave., Lafayette, Lafayette St., Central Expwy. From Bowers Dr. to UPRR MH S53-41 to MH S67-18
Install 12,200 feet of 24-inch pipe.
Projects 1 and 2.
Bowers Ave., Mission College Blvd., and Great America Pkwy. from Chromite to south of Hetch Hetchy ROW
Diameter of existing deficient pipes: 27"-36"
UPRR Permit required for crossing. Permanent easement needed for crossing into parking lot on north side of UPRR to Walsh. SCVWD permit required for crossing San Tomas Creek. County permit required for crossing San Tomas Expwy. and work in Central Expwy. Best placement for new sewer along Walsh is on north side (to avoid 15" sewer, 12" water, and 15" storm drain. On Walsh between Scott and Lafayette, reolcation of existing water line may be needed. Best placement for new sewer along Lafayette is on west side (to avoid 45" storm drain and 12" water). Siphons (assume twin 15") required to cross San Tomas Aquino Creek and storm drains at Scott and Lafayette.
City of Santa Clara
Sanitary Sewer Capacity Assessment Project WEST-TO-EAST May 2007 PROJECT ID:…………………………………………4A
PROJECT LOCATION:………………………………
BRIEF PROJECT DESCRIPTION:…………………
SANITARY SEWER PLAT MAP(S):…………………
LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:………………………
ALTERNATIVES:………………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
Monroe St. 24 8-16 600' 220 $/ft $132,000
Chromite Dr. 27 8-16 1,600' 240 $/ft $384,000
Collector line on Monroe St 8 8-16 600' 160 $/ft $96,000 Collector line of Chromite Dr. 8 8-16 1,600' 160 $/ft $256,000 Lower Laterals plus Cleanout (Monroe St.) 8 $2,000 $16,000 Lower Laterals plus Cleanout (Chromite Dr.) 22 $2,000 $44,000 Structures
Sewer Junction Structure: Chromite and Monroe $6,000 $6,000
SITE SPECIFIC CONSTRUCTION COST
Bypass Pumping / Flow Diversion Costs 10% of baseline pipe cost 10% $51,600 Remove and Replace Factor 2% of baseline pipe cost 2% $10,320 SUBTOTAL $995,920
Mobilization and Demobilization 5% $49,796
Traffic Control 10% $99,592
CONSTRUCTION COST SUBTOTAL $1,145,308
Contingencies 30% $343,592
CONSTRUCTION COST TOTAL $1,488,900
Engineering and Inspection Costs 25% $372,225
CAPITAL IMPROVEMENT COST TOTAL $1,861,126
ENR = 9103 (S.F. March 2007) rounded $1,861,000
Parallel pipe (if space available)
Same as project location
Diameter of existing deficient pipes: 18"
Assume parallel 8" collector sewer for lateral connections. 52, 53
TRUNK SEWER SYSTEM PROJECT DESCRIPTION
Monroe St. and Chromite Dr. from Machado Ave. to west of Bowers Ave.
MH S52-80 TO S53-41
Replace 600 feet of 18-inch pipe with 24-inch pipe. Replace 1,600 feet of 18- inch pipe with 27-inch pipe.
City of Santa Clara
Sanitary Sewer Capacity Assessment Project 4A May 2007
PROJECT ID:……………………………………………………… 4B
PROJECT LOCATION:……………………………………………
BRIEF PROJECT DESCRIPTION:……………………
SANITARY SEWER PLAT MAP(S):……………………………
LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:…………………………..
ALTERNATIVES:……………………………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
Machado 21 8-16 1,500' 210 $/ft $315,000
Collector line on Machado 8 8-16 1,500' 160 $/ft $240,000 Lower Laterals plus Cleanout (Machado) 55 $2,000 $110,000 Structures
Sewer Junction Structure: Machado and Monroe $6,000 $6,000
SITE SPECIFIC CONSTRUCTION COST
Bypass Pumping / Flow Diversion Costs 10% of baseline pipe cost 10% $31,500 Remove and Replace Factor 2% of baseline pipe cost 2% $6,300 SUBTOTAL $708,800
Mobilization and Demobilization 5% $35,440
Traffic Control 10% $70,880
CONSTRUCTION COST SUBTOTAL $815,120
Contingencies 30% $244,536
CONSTRUCTION COST TOTAL $1,059,656
Engineering and Inspection Costs 25% $264,914
CAPITAL IMPROVEMENT COST TOTAL $1,324,570
ENR = 9103 (S.F. March 2007) rounded $1,325,000
52 TRUNK SEWER SYSTEM PROJECT DESCRIPTION
Machado Ave. from Calabazas Blvd. to Monroe St.
MH S52-103 TO S52-80
Replace 1,500 feet of 15-inch pipe with 21-inch pipe.
Parallel pipe (if space available)
Same as project location.
Diameter of existing deficient pipes: 15"
Assume parallel 8" collector sewer for lateral connections.
City of Santa Clara
Sanitary Sewer Capacity Assessment Project 4B May 2007
PROJECT ID:…………………………………………………………5
PROJECT LOCATION:………………………………………………
BRIEF PROJECT DESCRIPTION:……………………
SANITARY SEWER PLAT MAP(S):……………………………
LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:…………………………..
ALTERNATIVES:……………………………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
Monroe 12 8-16 2,400' 170 $/ft $408,000
Siphon at Calabazas Creek (casing) 36 Microtunnel 100' 900 $/ft $90,000 Siphon pipe 8 Carrier Pipe 100' 150 $/ft $15,000
Lower Laterals plus Cleanout (Monroe) 8 $2,000 $16,000
Jacking Pits 1 pits $70,000 $70,000
Receiving Pits 1 pits $40,000 $40,000
Structures
Siphon structure- Calabazas Creek 2 structures $6,000 $12,000
SITE SPECIFIC CONSTRUCTION COST
Bypass Pumping / Flow Diversion Costs 10% of baseline pipe cost 10% $40,800 Remove and Replace Factor 2% of baseline pipe cost 2% $8,160 SUBTOTAL $699,960
Mobilization and Demobilization 5% $34,998
Traffic Control 10% $69,996
CONSTRUCTION COST SUBTOTAL $804,954
Contingencies 30% $241,486
CONSTRUCTION COST TOTAL $1,046,440
Engineering and Inspection Costs 25% $261,610
CAPITAL IMPROVEMENT COST TOTAL $1,308,050
ENR = 9103 (S.F. March 2007) rounded $1,308,000
Project extents from S52-51 to S-52-65 could possibly be eliminated by diversion into 24" Calabazas trunk sewer if sufficient capacity is available.
Pipe bursting could be an alternative to remove and replace.
Same as project location
Diameter of existing deficient pipes: 10" (6" siphon)
51, 52
TRUNK SEWER SYSTEM PROJECT DESCRIPTION
Monroe St. from Fordham Dr. to Chromite Dr.
MH S51-22 TO S52-65
Replace 2,400 feet of 10-inch pipe with 12-inch pipe. Parallel 6" siphon under Calabazas Creek with 8-inch siphon.
City of Santa Clara
Sanitary Sewer Capacity Assessment Project 5 May 2007
PROJECT ID:………………………………………6
PROJECT LOCATION:……………………………
BRIEF PROJECT DESCRIPTION:………………
SANITARY SEWER PLAT MAP(S):………………
LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:……………………
ALTERNATIVES:……………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
Nobili Ave 15 8-16 700' 180 $/ft $126,000
Nobili Ave and Machado Ave 18 8-16 2,400' 190 $/ft $456,000 Lower Laterals plus Cleanout (Nobili Ave) 31 $2,000 $62,000 Lower Laterals plus Cleanout (Machado Ave) 21 $2,000 $42,000 Structures
Sewer Junction Structure: Machado and Calabazas $6,000 $6,000
SITE SPECIFIC CONSTRUCTION COST
Bypass Pumping / Flow Diversion Costs 10% of baseline pipe cost 10% $58,200 Remove and Replace Factor 2% of baseline pipe cost 2% $11,640 SUBTOTAL $761,840
Mobilization and Demobilization 5% $38,092
Traffic Control 10% $76,184
CONSTRUCTION COST SUBTOTAL $876,116
Contingencies 30% $262,835
CONSTRUCTION COST TOTAL $1,138,951
Engineering and Inspection Costs 25% $284,738
CAPITAL IMPROVEMENT COST TOTAL $1,423,689
ENR = 9103 (S.F. March 2007) rounded $1,424,000
Pipe bursting could be an alternative to remove and replace.
Same as project location.
Diameter of existing deficient pipes: 10"-15"
41, 51, 52
TRUNK SEWER SYSTEM PROJECT DESCRIPTION
Nobili Ave. and Machado Ave. from Flora Vista Ave. to Calabazas Blvd.
MH S41-53 TO S52-101
Replace exisiting 10-inch, 12-inch and 15-inch pipe with 700 feet of 15-inch pipe and 2,400 feet of 18-inch pipe.
City of Santa Clara
Sanitary Sewer Capacity Assessment Project 6 May 2007
PROJECT ID:………………………………………8
PROJECT LOCATION:……………………………
BRIEF PROJECT DESCRIPTION:………………
SANITARY SEWER PLAT MAP(S):………………
LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:……………………
ALTERNATIVES:……………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
El Camino Real, Flora Vista to Pomeroy 12 8-16 1,800' 170 $/ft $306,000 El Camino Real, Pomeroy to Calabazas 15 8-16 800' 180 $/ft $144,000 Lower Laterals plus Cleanout (El Camino Real) 12 $2,000 $24,000
SITE SPECIFIC CONSTRUCTION COST
Bypass Pumping / Flow Diversion Costs 10% of baseline pipe cost 10% $45,000 Remove and Replace Factor 2% of baseline pipe cost 2% $9,000 Concrete Pavement Replacement Allowance 2,600' 40 $/ft $104,000 SUBTOTAL $632,000
Mobilization and Demobilization 5% $31,600
Traffic Control 10% $63,200
CONSTRUCTION COST SUBTOTAL $726,800
Contingencies 30% $218,040
CONSTRUCTION COST TOTAL $944,840
Engineering and Inspection Costs 35% $330,694
CAPITAL IMPROVEMENT COST TOTAL $1,275,534
ENR = 9103 (S.F. March 2007) rounded $1,276,000
31, 32, 41, 42
TRUNK SEWER SYSTEM PROJECT DESCRIPTION
El Camino Real from Flora Vista Ave. to siphon at Calabazas Creek.
MH S41-113 TO S32-5
Replace 2,600 feet of 10-inch pipe with 12- and 15-inch pipe.
Pipe bursting could be an alternative to remove and replace. Possible alternative alignment on Flora Visa Ave, from El Camino Real to Nobili (upstream end of project 6).
Same as project location
Diameter of existing deficient pipes: 10"
Permits required from Caltrans.
City of Santa Clara
Sanitary Sewer Capacity Assessment Project 8 May 2007
PROJECT ID:………………………………………9
PROJECT LOCATION:……………………………
BRIEF PROJECT DESCRIPTION:………………
SANITARY SEWER PLAT MAP(S):………………
LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:……………………
ALTERNATIVES:……………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
Scott Blvd. 10 8-16 800' 160 $/ft $128,000
Lower Laterals plus Cleanout (Scott Blvd.) 14 $2,000 $28,000
SITE SPECIFIC CONSTRUCTION COST
Bypass Pumping / Flow Diversion Costs 10% of baseline pipe cost 10% $12,800 Remove and Replace Factor 2% of baseline pipe cost 2% $2,560 SUBTOTAL $171,360
Mobilization and Demobilization 5% $8,568
Traffic Control 10% $17,136
CONSTRUCTION COST SUBTOTAL $197,064
Contingencies 30% $59,119
CONSTRUCTION COST TOTAL $256,183
Engineering and Inspection Costs 35% $89,664
CAPITAL IMPROVEMENT COST TOTAL $345,847
ENR = 9103 (S.F. March 2007) rounded $346,000
Pipe bursting could be an alternative to remove and replace.
Same as project location.
Diameter of existing deficient pipes: 8"
25, 35
TRUNK SEWER SYSTEM PROJECT DESCRIPTION
Scott Blvd. from Serra Ave. to Homestead Rd.
MH S25-37 TO S35-98
Replace 800 feet of 8-inch pipe with 10-inch pipe.
City of Santa Clara
Sanitary Sewer Capacity Assessment Project 9 May 2007
PROJECT ID:………………………………………10
PROJECT LOCATION:……………………………
BRIEF PROJECT DESCRIPTION:………………
SANITARY SEWER PLAT MAP(S):………………
LOCATION OF CAPACITY DEFICIENCY: ……
SPECIAL CONSIDERATIONS:……………………
ALTERNATIVES:……………………………………
MAJOR ITEMS DIA. (in.) DEPTH
(feet)
LENGTH
(feet) UNIT COST COST
BASELINE CONSTRUCTION COST
Pipe Construction
Park Ave. 12 8-16 250' 170 $/ft $42,500
Lower Laterals plus Cleanout (Park Ave.) 2 $2,000 $4,000
SITE SPECIFIC CONSTRUCTION COST
Bypass Pumping / Flow Diversion Costs 10% of baseline pipe cost 10% $4,250 Remove and Replace Factor 2% of baseline pipe cost 2% $850 SUBTOTAL $51,600
Mobilization and Demobilization 5% $2,580
Traffic Control 10% $5,160
CONSTRUCTION COST SUBTOTAL $59,340
Contingencies 30% $17,802
CONSTRUCTION COST TOTAL $77,142
Engineering and Inspection Costs 35% $27,000
CAPITAL IMPROVEMENT COST TOTAL $104,142
ENR = 9103 (S.F. March 2007) rounded $104,000
38 TRUNK SEWER SYSTEM PROJECT DESCRIPTION
Park Ave. south of Bellomy St.
MH S38-75 TO S38-66
Replace 250 feet of 10-inch pipe with 12-inch pipe.
Pipe bursting could be an alternative to remove and replace.
Same as project locatin.
Diameter of existing deficient pipes: 10"
City of Santa Clara
Sanitary Sewer Capacity Assessment Project 10 May 2007
Water and Environment
2290 North First Street
Suite 212
San Jose, CA 95131
T 408.240.8160
F 408.240.8161
www.rmcwater.com
City of Santa Clara
Sanitary Sewer Master Plan Update
Final Report
Prepared by:
April 2016
City of Santa Clara
Sanitary Sewer Master Plan Update
April 2016 i
Table of Contents
Executive Summary ...................................................................................................................... 1 Background and Purpose of Master Plan ..................................................................................... 1 How the Capacity Assessment Was Prepared ............................................................................. 2 Recommended Capacity Improvement Program .......................................................................... 6 Chapter 1 Introduction ............................................................................................................. 1-1
1.1 Background and Study Objectives .......................................................................... 1-1
1.2 Scope of Study ........................................................................................................ 1-2
1.3 Report Organization ................................................................................................ 1-4 Chapter 2 Basis of Flow Estimates .......................................................................................... 2-1
2.1 Wastewater Flow Components ............................................................................... 2-1
2.2 Base Wastewater Flow ........................................................................................... 2-2
2.2.1 Existing Base Wastewater Flow .............................................................................. 2-2
2.2.2 Future Base Wastewater Flow ................................................................................ 2-2
2.2.3 Diurnal Curves ........................................................................................................ 2-5
2.3 Groundwater Infiltration ........................................................................................... 2-7
2.4 Rainfall-Dependent I/I ............................................................................................. 2-7
2.5 Flow from Cupertino Sanitary District ...................................................................... 2-8 Chapter 3 Hydraulic Model Development ................................................................................ 3-1
3.1 Modeling Terminology ............................................................................................. 3-1
3.2 Delineation of Modeled System .............................................................................. 3-1
3.3 Model Network Construction and Validation ........................................................... 3-4
3.4 Flow Monitoring Program ........................................................................................ 3-4
3.5 Model Calibration .................................................................................................... 3-9
3.5.1 Dry Weather Calibration .......................................................................................... 3-9
3.5.2 Wet Weather Calibration ....................................................................................... 3-11 Chapter 4 Capacity Analysis .................................................................................................... 4-1
4.1 Design Event Criteria .............................................................................................. 4-1
4.1.1 Design Storm Condition .......................................................................................... 4-1
4.2 Hydraulic Capacity Criteria ...................................................................................... 4-2
4.2.1 Capacity Deficiency Criteria .................................................................................... 4-3
4.2.2 Sizing Criteria for New Sewer Facilities .................................................................. 4-4
4.3 Capacity Analysis Results and Proposed Solutions ................................................ 4-5
4.3.1 Pump Station Firm Capacity Analysis ..................................................................... 4-8 Chapter 5 Recommended Capacity Improvement Program .................................................. 5-10
5.1 Development of Capacity Improvement Projects .................................................. 5-10
5.2 Implementation Recommendations ....................................................................... 5-13 Appendices
Appendix A - Plots of Flow Monitoring Data and Summary of Daily Flows Appendix B - Dry Weather Flow Calibration Graphs
Appendix C - Wet Weather Flow Calibration Graphs
Appendix D - Model Hydraulic Profiles of Capacity Deficiencies Appendix E - Rabello & Northside Pump Station Capacity and Forcemain Calibration TM Appendix F - Project Descriptions and Cost Estimates
Appendix G - General Plan Land Use and Recent (2009-2015) Developments City of Santa Clara
Sanitary Sewer Master Plan Update
April 2016 ii
List of Tables
Table ES-1: Collection System Flow Estimates ............................................................................ 6 Table ES-2: Recommended Capacity Improvement Projects ..................................................... 10 Table 2-1: Base Wastewater Flow Unit Flow Factors ................................................................ 2-4 Table 2-2: Base Wastewater Flow Estimates ............................................................................ 2-5 Table 2-3: City’s Large Water Users .......................................................................................... 2-6 Table 3-1: Sewer Collection System Model Summary ............................................................... 3-2 Table 3-2: Collection System Pump Station Summary .............................................................. 3-2 Table 3-3: Summary of Flow Monitoring Sites ........................................................................... 3-5 Table 3-4: Dry Weather Flow Calibration Results .................................................................... 3-10 Table 3-5: Wet Weather Flow Calibration Results ................................................................... 3-12 Table 4-1: Summary of Capacity Analysis Results .................................................................... 4-5 Table 4-2: Capacity Deficiencies and Proposed Solutions ........................................................ 4-6 Table 4-3: Pump Station Firm Capacity Analysis ....................................................................... 4-8 Table 4-4: Recommended Revised Set Levels for Lift Stations ................................................. 4-9 Table 5-1: Recommended Capacity Improvement Projects .................................................... 5-11 List of Figures
Figure ES-1: Sanitary Sewer Collection System Overview ........................................................... 3 Figure ES-2: Modeled Trunk System ............................................................................................ 4 Figure ES-3: Recent and Future Growth Areas ............................................................................ 5 Figure ES-4: Model Predicted System Surcharge Under Future PWWF ...................................... 8 Figure ES-5: Capacity Improvement Projects and Project for Entitlement Compliance ................ 9 Figure 1-1: Study Area ............................................................................................................... 1-3 Figure 2-1: Wastewater Flow Components ................................................................................ 2-1 Figure 2-2: Recent and Future Growth Areas ............................................................................ 2-3 Figure 2-3: Wastewater Diurnal Curves ..................................................................................... 2-5 Figure 2-4: RDI/I Hydrograph Components ............................................................................... 2-8 Figure 3-1: Modeled Trunk System ............................................................................................ 3-3 Figure 3-2: Subcatchments and Loading Manholes .................................................................. 3-6 Figure 3-3: Flow Meter and Rain Gauge Locations ................................................................... 3-7 Figure 3-4: Trunk Sewer System Schematic ............................................................................. 3-8 Figure 3-5: Example Dry Weather Calibration Graphs ............................................................ 3-11 Figure 3-6: Example Wet Weather Calibration Graphs for 2014 Storm Period........................ 3-13 Figure 4-1: Design Storm Pattern for the San Jose International Airport MAP Area ................. 4-2 Figure 4-2: PWWF Hydraulic Deficiency Criteria for Gravity Sewers ......................................... 4-4 Figure 4-3: Model Predicted System Surcharge Under Future PWWF...................................... 4-7 Figure 5-1: Capacity Improvement Projects and Project for Entitlement Compliance ............. 5-12 City of Santa Clara
Sanitary Sewer Master Plan Update
April 2016 iii
Acknowledgements
City of Santa Clara
Rajeev Batra, Director of Public Works/City Engineer
Falguni Amin, Principal Civil Engineer
Evelyn Liang, Senior Civil Engineer (Project Manager)
Kimchi Tran, Civil Engineer
Christopher de Groot, Director of Water and Sewer Utilities Shilpa Mehta, Principal Engineer
Garrett Brown, Sanitary Sewer Assistant Superintendent
Gloria Sciara, Development Review Officer
Jeff Schwilk, Associate Planner
Debby Fernandez, Project Planner
Payal Bhagat, Associated Planner
RMC Water and Environment
Gisa Ju, Principal-in-Charge/Technical Director
Steve Bui, Project Manager
Winola Cheong, Project Engineer
V&A Consulting Engineers, Flow Monitoring
Schaaf & Wheeler Consulting Civil Engineers, Pump Station Capacity Assessment City of Santa Clara
Sanitary Sewer Master Plan Update
April 2016 iv
Abbreviations and Definitions
ABAG Association of Bay Area Governments
ABWF Average base wastewater flow
ADWF Average dry weather flow
APN Assessor parcel number
Backwater A condition in which the hydraulic gradeline (see definition of HGL below) increases upstream of a location in the system due to a downstream hydraulic constriction.
BWF Base wastewater flow: sanitary and process flow contributions from residential, commercial, institutional, and industrial users.
CIP Capital Improvement Program
City City of Santa Clara
CSJ City of San Jose
CuSD Cupertino Sanitary District
d/D Ratio of flow depth to pipe diameter
Design Storm A rainfall event, defined based on statistical probability of occurrence, which determines the peak wet weather flow conditions for which the capacity of sewer system facilities are evaluated and/or designed.
Diurnal Curve Change in dry weather flow over a typical 24-hour period on an hourly basis.
DU Dwelling unit
DWF Dry weather flow: the flow during non-rainfall periods, composed of normal base wastewater flow plus any dry season groundwater infiltration.
ENR-CCI Engineering News Record Construction Cost Index; an index published monthly by Engineering News Record magazine and used to reference construction costs (such as those for wastewater system facilities) to a specific date and location.
Firm capacity The capacity of a pump station with the largest pump out of service. fps Feet per second
GIS Geographic Information System: a computerized system in which geographical features (e.g., sewer facilities, parcels, land use) are linked to an attribute database to facilitate analysis and presentation of information
gpad or gpd/ac Gallons per day per acre
gpcd Gallons per capita per day
gpd Gallons per day
GWDR General Waste Discharge Requirements for Sanitary Sewer Systems: regulations adopted by the State Water Resources Control Board in 2006 that address the operation, maintenance, and management of publicly-owned sanitary sewer systems in California
City of Santa Clara
Sanitary Sewer Master Plan Update
April 2016 v
GWI Groundwater infiltration: extraneous water that infiltrations into a sewer system from the ground through defective pipes and manholes. Groundwater infiltration is considered to be a relatively constant daily flow that varies seasonally and depends on location of sewers with respect to the groundwater table.
HGL Hydraulic Grade Line: in a gravity pipeline system, the water surface elevation in the pipes; or in a system flowing under pressure, the elevation representing the sum of pressure head plus elevation head
Hydrograph A graph of flow versus time.
IDF Intensity-duration-frequency: rainfall statistics that establish the rainfall intensity over specified durations for various recurrence frequencies I/I Infiltration/inflow (see definitions below)
Infiltration Extraneous groundwater or storm water that enters sewer pipes, manholes, and service laterals via the soil through breaks, cracks, and defective joints.
Inflow Storm water that enters the sewer system from the ground surface through direct drainage connections (e.g., directly connected catch basins, area drains, or roof drains) or through manhole or cleanout lids.
Inverted Siphon A sewer configuration (also called a “siphon”), typically consisting of a downward leg, horizontal section, and upward leg, in which the flow is forced through the pipe by the pressure head created by the elevation difference between the upstream and downstream ends of the siphon. An inverted siphon is typically used to cross under a creek, channel, or another pipeline.
Isohyetal A contour of equal precipitation (typically average annual rainfall) K Recession coefficient of RDI/I unit hydrograph (see Figure 2-4) lf Linear feet
Loading Manhole A manhole in the modeled sewer network to which flows from unmodeled sewers discharge into the modeled network (also see definition of subcatchment below).
LS Lift Station
MAP Mean annual precipitation
mgd Million gallons per day
NAICS North American Industrial Classification System
O&M Operations and maintenance
PDWF Peak dry weather flow: the peak flow during non-rainfall periods.
PS Pump Station
PWWF Peak wet weather flow: the peak flow during a given storm event from dry weather flow plus infiltration and inflow.
R Ratio of RDI/I volume to rainfall volume
RDI/I Rainfall-dependent infiltration/inflow: the infiltration and inflow into a sewer system directly related to a rainfall event. RDI/I may cause rapid, short-term peak flows in the sewer system that recede after the rainfall has ended.
RG Rain gauge
RMC RMC Water and Environment
City of Santa Clara
Sanitary Sewer Master Plan Update
April 2016 vi
sf or sq. ft. Square feet
SCVWD Santa Clara Valley Water District
SECAP System Evaluation and Capacity Assurance Plan
Siphon See Inverted Siphon
SJ/SC RWF San Jose / Santa Clara Regional Wastewater Facility SSMP Sewer System Management Plan
SSO Sanitary sewer overflow
Subcatchment A small area of the sewer system that contributes flow to the modeled sewer network, in which the unmodeled collection sewers are assumed to discharge to a common point (manhole) in the modeled network
Surcharge The hydraulic condition in a sewer pipeline in which the elevation of the hydraulic gradeline (water level) is above the crown (top) of the pipe. Under such a condition, the water in the pipe rises into the manholes and could overflow onto the ground if the hydraulic gradeline exceeds the elevation of the manhole rims.
T Time to peak of RDI/I unit hydrograph (see Figure 2-4) TM Technical Memorandum
WWF Wet weather flow: the flow during rainfall periods, composed on base wastewater flow, wet season groundwater infiltration, and rainfall-dependent I/I.
City of Santa Clara
Sanitary Sewer Master Plan Update Executive Summary
April 2016 ES-1
Executive Summary
This report summarizes the results and recommendations of the Sanitary Sewer Master Plan Update (Master Plan) for the City of Santa Clara (City). The Master Plan was prepared by RMC Water and Environment (RMC) in close coordination with City staff. The Master Plan will be used to guide improvements to the City’s sanitary sewer system to accommodate current and future development and ensure that the City continues to provide a high level of service to its customers.
Background and Purpose of Master Plan
The City of Santa Clara is located in central Santa Clara County adjacent to the Cities of San Jose, Cupertino, and Sunnyvale. The City has a population of approximately 120,000 and is served by a wastewater collection system consisting of approximately 270 miles of sewer pipelines and seven sewage pump stations. The system collects wastewater flows generated within the City limits and also flows from the major portion of the Cupertino Sanitary District (CuSD) via a connection at Homestead Road and Swallow Drive. Flow is conveyed eastward to the City of San Jose’s interceptor sewer on Zanker Road and also northward to the Northside and Rabello Pump Stations, where the flow is pumped to the San Jose/Santa Clara Regional Wastewater Facility (SJ/SC RWF) for treatment and disposal. The City’s sewer system and service area are shown in Figure ES-1.
The City’s last sanitary sewer master plan was completed in 20071 . Since that time, the City has completed
a number of sewer improvement projects and is experiencing significant growth and redevelopment in a number of areas, necessitating an evaluation of the capacity of the sanitary sewer system to handle future wastewater flows. This Master Plan will help identify future capital needs for capacity improvements and associated requirements for financing those improvements through increased connection fees or other sources of funding.
The City is also required to comply with the Statewide General Waste Discharge Requirements for Sanitary Sewer Systems (GWDR) adopted in 2006 by the State Water Resources Control Board. The GWDR, which applies to all publicly-owned sewer systems in California, includes the requirement to complete a Sewer System Management Plan (SSMP). The SSMP addresses the overall management, operation, and maintenance of the sanitary sewer system and must include a System Evaluation and Capacity Assurance Plan (SECAP). Therefore, this Master Plan is also intended to satisfy the SECAP requirements of the SSMP.
The overall objectives of this Master Plan are to develop wastewater flow projections for the City’s collection area using up-to-date water use and land use information and flow monitoring data; develop an updated hydraulic model of the trunk sewer system; use the model to identify existing capacity deficiencies and future projected capacity requirements; and develop a Capital Improvement Program (CIP), including budget estimates, for implementing the required capacity improvements to the collection system.
This Executive Summary is presented in two parts:
How the Capacity Assessment Was Prepared describes the scope and methodologies of the planning effort, including the key planning and technical assumptions incorporated into the sewer system capacity analysis.
Recommended Capacity Improvement Program presents the recommended CIP, including capacity improvement projects, priorities, and estimated costs. In addition, recommendations are presented for implementing the proposed capacity improvement program.
1 City of Santa Clara Sanitary Sewer Capacity Assessment, RMC Water and Environment, May 2007.
City of Santa Clara
Sanitary Sewer Master Plan Update Executive Summary
April 2016 ES-2
How the Capacity Assessment Was Prepared
The City’s wastewater collection system includes sewer pipelines ranging in size from 4 to 48 inches in diameter. The larger pipes, primarily the 10-inch and larger sewers and a portion of the smaller diameter pipes, comprise the trunk sewer system, which is the primary network for conveying flows generated from the City’s service area and CuSD to the SJ/SC RWF. The trunk sewer system, comprising about 34 percent of the total pipe footage in the system, was the focus of the capacity assessment in this study.
The project team used a systematic process that incorporated land use planning information, water use and flow monitoring data, and design criteria for estimating wastewater flows, applied in a computer hydraulic model of the trunk sewer system. The modeled system is shown in Figure ES-2. The model was used to assess how the system would perform under various planning and flow scenarios and identify pipes and/or pump stations that may not have sufficient capacity to convey the predicted flows under existing or future conditions. Improvement projects were developed to provide the required capacity, the capital costs of the required projects were estimated, and the projects were prioritized based on the model results.
Capacity Assessment Considers Existing and Future Planning Scenarios Two planning scenarios were evaluated for this study: existing (2015) and future (2035) scenarios. The existing scenario examined the current capacity of the sewer system based on existing land use, with flows defined based on winter water use data and calibrated to flow monitoring data collected in the 2014/15 winter season. The future scenario incorporated information on planned development provided by the City.
Figure ES-3 shows the location of the areas of anticipated development. Planned development within the City represents over 15,000 new residential dwelling units and over 20 million square feet of commercial and industrial building floor space. In addition, CuSD has also projected an increase in their base wastewater flow due to anticipated additional development. Together, these projections are estimated to increase current base wastewater flows by over two folds. The future scenario was used to examine the impact on the system of future increases in wastewater flows due to anticipated development and determine the required sewer system capacity needed to serve both existing and future users.
Potential Capacity Deficiencies under Existing and Future Flow Conditions For each of the planning scenarios, projected dry and wet weather flows were simulated in the hydraulic model. The model was calibrated to flow monitoring data to ensure that it represents a reasonably accurate depiction of system conditions. For this study, a flow monitoring program consisting of 25 temporary flow meters installed in the system during the 2014/15 wet weather season was conducted to provide data to calibrate the hydraulic model and verify existing system flows. The collected data was useful for confirming dry weather flows and characterizing the relative wet weather flow response in different areas of the system.
The model integrates various dry and wet weather flow parameters to determine system capacity under different flow and planning scenarios. Key flow components incorporated into the model included: base (dry weather) wastewater flow (BWF), estimated based on winter water use data; groundwater infiltration (GWI), which occurs when water seeps into pipes under the ground through cracks and pipe joints; and rainfall-dependent infiltration and inflow (RDI/I) during storm events. For this Master Plan, a 10-year return period, 24-hour duration rainfall event was selected as the “design storm” to serve as the basis for computing design peak wet weather flows in the system. A 10-year return period has become a standard design storm criterion for many Bay Area agencies. Table ES-1 presents the estimated existing and future average dry weather flow (ADWF) and peak wet weather flow (PWWF) for the selected design storm for the City’s sewer system, based on the modeling conducted for this study. 0 0.5
1 Mile µ Legend
Sew ers by Diam eter:
≤ 6"
8" - 10"
12" - 16"
18" - 24"
≥ 27"
ÉP Pum p/Lift Station
Santa Clara Force Mains
San Jose Interceptors
City Lim it
J:\Projects\149 SANTA CLARA\149-008 Santa Clara 2015 Sanitary Sew er MP U pdate\G. GIS Files\_MXDs\Master Plan Report Figures\MPFigES1_System Overview _05Apr2016.m xd City of Santa Clara
Sanitary Sew er
Master PlanU pdate
Figure ES-1
Sanitary Sewer Collection
System Overview
0 0.5
1 Mile µ Legend
Modeled Trun k Sew ers
≤ 6"
8" - 10"
12" - 16"
18" - 24"
≥ 27"
ÉP Modeled Pum p/Lift Station
Un m odeled Sew ers
San Jose In terceptors
City Lim it
J:\Projects\149 SANTA CLARA\149-008 San ta Clara 2015 San itary Sew er MP Update\G. GIS Files\_MX Ds\Master Plan Report Figures\MPFigES2_ModeledNtw k_05Apr2016.m xd City of San ta Clara
San itary Sew er
Master Plan Update
Figure ES-2
Modeled Trunk System
0 0.5 1 Mile
Legend
Recent (2009-2015) Development Projects
General Plan Phase 3 (2035) Development
µ
ÉP Pump/Lift Station
Modeled Trunk Sewers
Unmodeled Sewers
San Jose Interceptors
City Limit
J:\Projects\149 SANTA CLARA\149-008 Santa Clara 2015 Sanitary Sewer MP Update\G. GIS Files\_MXDs\Master Plan Report Figures\MPFigES3_Dvpt_05Apr2016.mxd City of Santa Clara
Sanitary Sewer
Master Plan Update
Figure ES-3
Recent and
Future Growth Areas
CSJ Interceptor
(not modeled)
San Jose / Santa Clara
Regional
Wastewater Facility
SC Influent
Junction Structure
CuSD Flow
City of Santa Clara
Sanitary Sewer Master Plan Update Executive Summary
April 2016 ES-6
Table ES-1: Collection System Flow Estimates
Existing
ADWF (2)
(mgd)
Existing
PDWF (2)
(mgd)
Existing
PWWF (3)
(mgd)
Future
ADWF (2)
(mgd)
Future
PDWF (2)
(mgd)
Future
PWWF (3,4)
(mgd)
Flow Estimates by System Outfall (1)
North (to Northside and Rabello
Pump Stations) 10.2 15.2/16.0 27.9 24.6 33.5/34.4 41.0
East (to San Jose Zanker Road
Interceptor) 4.7 6.4 11.7 9.8 13.3 18.3
Total 14.9 21.6/22.4 39.6 34.4 46.8/47.7 59.4
Flow Estimates by Agency (1)
Santa Clara System 11.3 15.4/16.2 26.8 27.5 34.6/35.5 45.6 Cupertino Sanitary District 3.5 6.2 12.8 6.9 12.2 13.8
Total 14.9 21.6/22.4 39.6 34.4 46.8/47.7 59.4
1. Assuming that trunk sewer capacity deficiencies are relieved with recommended capital improvement projects presented in Table ES-2.
2. Includes groundwater infiltration for a typical wintertime period. ADWF and first value shown for PDWF includes typical non-game day flow from Levi’s Stadium; second value shown for PDWF includes a peak game day flow from Levi’s Stadium.
3. For 10-year design storm; assumes non-game day flow from Levi’s Stadium.
4. Assuming peak wet weather flow from CuSD would not increase above its contractual maximum flow of 13.8 mgd.
Model results were examined to determine trunk system capacity needs, as indicated by areas where the flow in the pipes would exceed their capacity and cause surcharge conditions (water levels higher than the tops of the pipes). Figure ES-4 shows the capacity assessment results for future PWWF conditions, indicating existing trunk sewers that were predicted by the model to be surcharged due to “throttle” conditions (peak flow exceeding full pipe capacity) or due to backwater from a downstream throttle condition, and locations of where the model predicts a surcharge condition severe enough to violate the City’s capacity criteria, defined as water level that exceeds one (1) foot above the top of pipe. Most of these locations were predicted to be capacity issues only under future PWWF. Note that the locations of criteria violations are not necessarily the locations of the actual capacity-deficient pipes, but are typically located further upstream due to backwater from downstream deficiencies.
Note that no overflows are predicted under design storm conditions. Furthermore, all of the modeled pump stations have adequate firm capacity (capacity with largest pumping unit out of service) to convey the predicted PWWF without violating freeboard criteria or resulting in sewer overflows, although for two of the stations (Westside and Tasman), noticeable backwater surcharge was predicted because the switch-on set points for the lead pumps are higher than the influent lines.
Recommended Capacity Improvement Program
The Capital Improvement Program (CIP) recommended in this study is designed to provide for adequate sewer system capacity for the City’s existing and anticipated future development. Figure ES-5 and Table ES-2 present the recommended capacity improvement projects. Projects have been assigned relative priorities based on the extent of criteria violations or surcharge. Priority 1 and 2 projects are required to address capacity deficiencies that result in criteria violations under current conditions, while Priority 3 projects are those that result in criteria violations under future conditions. In addition to these projects, there was also an additional project (Project E1) that was triggered by an entitlement requirement, discussed in more detail in Chapter 5.
City of Santa Clara
Sanitary Sewer Master Plan Update Executive Summary
April 2016 ES-7
As indicated in Table ES-2, the total estimated cost of the recommended capacity improvement program (without Project E1) is about $1.7 million. The total estimated cost, if the City implements Project P6-Alt instead of P6, would be approximately $2.8 million. Note that implementing Project P6-Alt would also increase the peak flow to the Rabello and Northside Pump Stations by about 1 mgd to each pump station, which could require further evaluation of and potential improvements to increase pump station capacity.
Implementation Recommendations
The City should begin implementation of the Capital Improvement Program recommended in this Master Plan, starting with the highest priority projects. The following items should be considered in project scheduling and design, and in future updates of the Master Plan. ▪ The alignments and sizes of projects should be verified with detailed predesign analyses, including topographic surveys, geotechnical investigations, utility research, and constructability reviews. ▪ The estimated costs assumed open cut construction, but alternative methods such as trenchless construction or construction of parallel relief pipes could be considered during design. The decision to parallel or replace existing sewers should consider the physical condition and remaining useful life of the existing pipelines; the availability of pipeline corridors for new sewer construction; and operation and maintenance concerns.
▪ The hydraulic model has been developed to assist the City in performing capacity analyses and updating the Master Plan in the future. The model should be kept up-to-date with changes to existing sewer connections, development plans, and sewer system facilities. ▪ The City should conduct additional flow monitoring at key locations in the sewer system, particularly the area tributary to the Chromite/Machado trunk sewers where both the 2006 and 2015 flow monitoring programs indicated high I/I. The City should also conduct smoke testing and television inspection to identify potential sources of I/I. Flow levels during large storm events should be compared to the peak flows simulated by the hydraulic model to verify the modeling predictions for the 10-year design storm and confirm the need for and sizing of Project P3 (Cabrillo Avenue Sewer Improvement). ▪ The City should coordinate with the CuSD on flow and planning assumptions to ensure that adequate capacity exists in the Santa Clara system to handle future flows from the District. The City should encourage CuSD to monitor the flows at the flow meter that it operates and maintains on Homestead Road at Swallow Drive on an on-going basis and periodically confirm meter calibration to verify the wastewater flows entering the Santa Clara system.
▪ The City should coordinate with the City of San Jose to ensure that its flow criteria and planning assumptions are consistent with those used by San Jose in its capacity master planning. ▪ The City should verify the need to implement project E1 (Tracy Drive Sewer Improvement). The project is triggered by the large sewer discharge assumed for parcel APN 316-17-018, which holds an entitlement agreement to discharge a potential flow of 0.95 mgd; however, it is currently discharging less than 10 percent of the entitled rate. While the City is obligated to provide capacity for entitlement holders, it is important to note that implementing this project now may result in oversized sewers where the current daily flow is not sufficient to provide the minimum cleaning velocity and thus creating potential debris and odor issues.
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Sanitary Sewer
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Figure ES-5
Capacity Improvement
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City of Santa Clara
Sanitary Sewer Master Plan Update Executive Summary
April 2016 ES-10
Table ES-2: Recommended Capacity Improvement Projects
Project
ID Priority Project Name U/S MHID D/S MHID Description Est. Capital Improvement Cost1 P12 1 Westside Lift Station Set Point Adjustment N/A N/A Adjust the set points for the pumps to a lower elevation to eliminate unnecessary backups in the influent line. -- P22 2 Tasman Lift Station Set Point Adjustment N/A N/A Adjust the set points for the pumps to a lower elevation to eliminate unnecessary backups in the influent line. -- P3 2 Cabrillo Avenue Sewer Improvement S41-13 S41-20 Upsize 1,600 feet of 8-inch line in Cabrillo Ave. between Lawrence Expressway and Nobili Ave. to a 12-inch line. $1,097,000 P4 3 Tasman Drive Sewer Improvement S93-24 S93-35 Upsize 600 feet of 12-inch line in Tasman Dr. between Old Ironsides Dr. and Great America Pkwy. to a 15-inch line. $327,000 P5 4 Sewer Diversion at Los Prades Boulevard and Saratoga Avenue S25-85 S25-85
Install a weir in manhole S25-85 located in the intersection of Padres Blvd. and Saratoga Ave. to divert flow northwest to the existing 12-in line in Los Padres Blvd. $77,000
P6 4
Sewer Diversion at Calabazas Boulevard and Machado Avenue U/S of
S52-93 S52-120
Install a new manhole upstream of S52-93 in the intersection of Calabazas Blvd. and Machado Ave., and install a new 15-inch high-level diversion line (approximately 200 feet) to divert excess flow from the existing 24-inch line in Calabazas Blvd. to the 21-inch line in Machado Ave. The diversion line should be about 6 inches higher than the invert of the 24-inch line. $166,000
P6-Alt.3 4 Calabazas Creek Sewer Improvement S62-31 S72-20 Upsize 1,800 feet of 24-inch line next to Calabazas Creek between Kifer Rd. and Scott Blvd. to a 27-inch line. $1,334,000 Estimated Total Cost for Recommended Projects P1 to P6:
Estimated Total Cost for Projects P1 to P5 and P6-Alt:
$1,667,000 $2,835,000
E14 N/A Tracy Drive Sewer Improvement S10-77 S22-51
Upsize approximately 6,600 feet of 10- to 12-inch line in Tracy Dr. and Pomeroy Ave. to a 15-inch line; install a new 15-inch line between manholes S22-55 and S22-46 in Pomeroy Ave. and Homestead Rd. (approximately 50 feet) to divert flow into Homestead Rd., and upsize approximately 1,400 feet of 18-inch line downstream to a 21-inch. $4,654,000
Estimated Total Cost (P1 to P6) including Project E1:
Estimated Total Cost (P1 to P5 and P6-Alt) including Project E1:
$6,321,000 $7,489,000
1. All costs are presented in 2015 dollars and include 30 percent allowance for contingencies for unknown conditions and 25 percent for engineering, administration, and legal costs. 2. These proposed projects are operational, not capital improvements. Refer to Table 4-4 for recommended set points. 3. Project P6-Alt is presented for the purpose of identifying the solution and associated cost to maintain the current system flow configuration. Project P6 is the recommended project. 4. Project E1 addresses the potential capacity deficiency when parcel APN 316-17-018 begins to discharge its entitled flow of 0.95 mgd into the City’s system.
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 1
Introduction
April 2016 1-1
Chapter 1 Introduction
This report presents the results and recommendations of the Sanitary Sewer Master Plan Update (Master Plan) for the City of Santa Clara (City). The report was prepared by RMC Water and Environment (RMC).
1.1 Background and Study Objectives
The City of Santa Clara is located in central Santa Clara County adjacent to the Cities of San Jose, Cupertino, and Sunnyvale. The City has a population of approximately 120,000 and is served by a wastewater collection system consisting of approximately 270 miles of sewer pipelines and seven sewage pump stations. The system collects wastewater flows generated within the City’s service area and also wastewater flows from the major portion of the Cupertino Sanitary District (CuSD) via a connection at Homestead Road and Swallow Drive. Flow is conveyed eastward to the City of San Jose’s interceptor sewer on Zanker Road and also northward to the Northside and Rabello Pump Stations, where the flow is pumped to the San Jose/Santa Clara Regional Wastewater Facility (SJ/SC RWF) for treatment and disposal. The City’s sewer system and service area are shown in Figure 1-1.
The City’s last sanitary sewer master plan was completed in 20072 . Since that time, the City has completed
a number of sewer improvement projects and is experiencing new development in a number of areas, necessitating an evaluation of the capacity of the sanitary sewer system to handle future wastewater flows.
This evaluation will help identify future capital needs for capacity improvements and associated requirements for financing those improvements through increased connection fees or other sources of funding. This Master Plan will confirm flows in the collection system and identify capital needs for capacity improvements.
The City is also required to comply with the Statewide General Waste Discharge Requirements for Sanitary Sewer Systems (GWDR) adopted in 2006 by the State Water Resources Control Board. The GWDR, which applies to all publicly-owned sewer systems in California, includes the requirement to complete a Sewer System Management Plan (SSMP). The SSMP addresses the overall management, operation, and maintenance of the sanitary sewer system and must include a System Evaluation and Capacity Assurance Plan (SECAP). Therefore, this Master Plan is also intended to satisfy the SECAP requirements of the SSMP.
The overall objectives of this Master Plan are to develop wastewater flow projections for the City’s collection area using up-to-date water use and land use information and flow monitoring data; develop an updated hydraulic model of the trunk sewer system; use the model to identify existing capacity deficiencies and future anticipated capacity requirements; and develop a phased Capital Improvement Program (CIP), including budget estimates, for implementing the required capacity improvements to the collection system.
2 City of Santa Clara Sanitary Sewer Capacity Assessment, RMC Water and Environment, May 2007.
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 1
Introduction
April 2016 1-2
1.2 Scope of Study
The scope of the Master Plan, as well as a brief discussion of work conducted under each task, is described below.
Task 1 – Project Management and Coordination. Periodic progress meetings were held with City staff to review project status and discuss project issues, and monthly status reports were prepared to document the work completed. Quality control was carried out, including checking of data and calculations, as well as senior review of proposed criteria, recommendations, and project deliverables. Task 2 – Data Collection and Review. Data, maps, geographic information system (GIS) files, and previous reports related to the wastewater collection system were reviewed to identify the information available for completing the Master Plan.
Task 3 – Flow Monitoring. A flow monitoring program, consisting of the 23 meters and 4 rain gauges installed in the collection system for a period of about two months during the 2014/15 wet weather season was conducted to obtain data to characterize flows in the system and calibrate the hydraulic model. Two additional FloDar meters were also installed at the Guadalupe Chart Station on the Trimble Road trunk sewer to confirm flows recorded by the City’s existing permanent meters at that site. Four of the sites were installed early, including a meter at Levi’s Stadium to capture the 2014 Thanksgiving Day football game, and at the three most downstream meters to capture total flows to the Rabello and Northside Pump Stations.
Task 4 – Hydraulic Model Update. An expanded hydraulic model of the City’s trunk sewer system was developed using InfoWorks™ CS modeling software. Subcatchments (small areas of unmodeled sewers that contribute flow to the modeled system) were delineated to define areas loading to the model, and flow loads to the model were compiled using water use and land use data and flow factors representing unit base wastewater flow (BWF) rates, diurnal BWF patterns, and infiltration/inflow (I/I).
The expanded model also included the Northside and Rabello Pump Stations, the two associated force mains, and a junction structure between the pump stations and the SJ/SC RWF. Meetings were held with City planning staff to identify and obtain pertinent land use data and to discuss specific planning issues and potential growth or development areas in the City. Additional meetings were also held with the City of Cupertino and the CuSD to obtain updated flow projections. The model was verified for system connectivity, calibrated for dry weather conditions, and then calibrated for wet weather conditions using actual storm events from the flow monitoring program under Task 3. Task 5 – Evaluate System Hydraulic Performance and Develop Capital Improvement Projects.
The model was used to determine sewer system capacity requirements and identify capacity deficiencies under peak dry and wet weather flow conditions, defined based on a design storm and system performance criteria. Potential solutions to capacity deficiencies were identified and tested in the model, and capacity improvement projects and associated costs were developed based on these analyses. The model was also used to confirm the results of the City’s 2010 Pump Station Evaluation to determine if the City’s pump stations are adequate to convey future flows. The recommended capacity improvement projects were prioritized to develop a Capital Improvement Program (CIP). Task 6 – Prepare Sanitary Sewer Master Plan (Update) Report. This report was prepared to summarize and present the results and recommendation of the study. 0 0.5
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Figure 1-1
Sanitary Sewer Collection
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City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 1
Introduction
April 2016 1-4
1.3 Report Organization
This report includes five Chapters, which are described below. Chapter 1, Introduction, presents the background, objectives, and scope of the Sanitary Sewer Master Plan Update.
Chapter 2, Basis of Flow Estimates, discusses the planning area land use projections, the basis for developing estimates for each component of wastewater flows, and the base wastewater flow projections for the service area.
Chapter 3, Hydraulic Model Development, describes the modeled sewer system, development of the model network and model loads, flow monitoring program, and model calibration. Chapter 4, Capacity Analysis, describes the capacity analysis and design criteria, model results, and potential solutions for identified capacity deficiencies. Chapter 5, Recommended Capacity Improvement Program, presents the recommended capacity improvement CIP, including project costs, prioritization, and implementation recommendations.
The Appendices to this report include plots of the flow monitoring data, model calibration graphs, model hydraulic profiles, and documentation for the recommended CIP, including project descriptions and cost estimates.
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 2
Basis of Flow Estimates
April 2016 2-1
Chapter 2 Basis of Flow Estimates
This chapter presents the basis of wastewater flow estimates for the City’s sanitary sewer system. The section describes the wastewater flow components used in the hydraulic model and the existing and projected future land uses for the City, which form the basis for generating base wastewater flows. Design flow estimates were developed based on criteria developed for each flow component: base wastewater flow, groundwater infiltration, and rainfall-dependent infiltration and inflow, and confirmed through model calibration, as described in Chapter 3 of this report.
2.1 Wastewater Flow Components
Wastewater flows include three components: base wastewater flow (BWF), groundwater infiltration (GWI), and rainfall-dependent infiltration/inflow (RDI/I), as illustrated conceptually in Figure 2-1. BWF represents the sanitary and process flow contributions from residential, commercial, institutional, and industrial users of the system. GWI is groundwater that infiltrates into defects in sewer pipes and manholes, particularly in winter and springtime in low-lying areas. GWI is typically seasonal in nature and remains relatively constant during specific periods of the year. RDI/I is storm water inflow and infiltration that enter the system in direct response to rainfall events, typically through direct connections such as holes in manhole covers or illegally connected roof leaders or area drains or, more commonly, through defects in sewer pipes, manholes, and service laterals that may have resulted from poor initial construction, settlement of trench backfill, or deterioration due to age. RDI/I typically results in short-term peak flows that recede quickly after the rainfall ends.
Figure 2-1: Wastewater Flow Components
Flow
Rainfall
Time
(24 Hours)
RDI/I
BWF
GWI
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 2
Basis of Flow Estimates
April 2016 2-2
2.2 Base Wastewater Flow
For the City’s Master Plan Update, BWF loads were developed for both existing and future development conditions. Existing loads were developed based on average winter water use data from the City’s customer billing records, and future loads were based mainly on the General Plan Phase 3 (2035) development forecast and known development and redevelopment projects that had occurred in recent years. The loading methodology for existing conditions and for projecting future BWF are discussed in the following subsections.
2.2.1 Existing Base Wastewater Flow
Existing BWF was estimated based on actual water billing records in the City’s customer billing database.
Data were first processed to exclude non-wastewater generating accounts such as fire, construction, or irrigation accounts; data for the remaining accounts were converted to average water use (in gallons per day, gpd) using the billing dates and quantities. Each account’s BWF was estimated based on the average water use during the four winter periods between December 2010 and February 2014. Each user was also assigned one of three land use types (residential, commercial, or industrial) according to the account’s North American Industry Classification System (NAICS) designation.
The City also has customers who use domestic wells and/or recycled water. The BWF for these customers were individually estimated based on their winter well usage data and recycled water billing data.
The BWF data (both water use and land use type) were further processed in GIS by geocoding the data to their corresponding parcels using the account’s service address. The total BWF for each sewer subcatchment was then estimated by overlaying the subcatchment boundary on the parcels and summing the BWF of all parcels within each subcatchment.
The data were then imported into the hydraulic model to perform a dry weather simulation run, and the results were compared to the flow data collected during the most recent flow monitoring program, in which a total of 25 meters were installed at selected locations throughout the system and collected actual flow data between November 2014 and March 2015 (see further discussion of model calibration in Chapter 3). It was noticed that the modeled flows were consistently about 10 to 20 percent higher than the observed flows.
One possible explanation was that there was some level of irrigation activities occurring even in the winter months due to the lack of rainfall in recent years. As such, a wastewater return factor of 10 to 20 percent was applied to the estimated BWF based on the water use data to attain a more reasonable match with actual flows observed in the field. The revised estimated BWF including the wastewater return factor is 6.5 million gallons per day (mgd) for residential accounts and 4.4 mgd for commercial and industrial accounts. These estimates do not include flow from the Levi’s Stadium, which varies widely depending on the use of the venue and could potentially generate daily peak flows ranging from less than 0.1 mgd (for local events such as team practice or stadium public tours) to 1.0 mgd or higher (for major events such as the Super Bowl).
2.2.2 Future Base Wastewater Flow
The future scenario for this Master Plan Update refers to the projected flow condition in year 2035, which is the planning horizon for the City’s current General Plan. The BWF for this scenario was estimated using multiple data sources, including the original General Plan Phase 3 development forecast that was prepared in 2009 plus various additions and corrections that City staff identified in 2015, development and redevelopment projects that have occurred between 2009 and 2015, and entitlement agreements for specific parcels. These areas are shown in Figure 2-2. A more detailed map and tabulation of the recent developments are included in Appendix G.
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Figure 2-2
Recent and
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SC Influent
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CuSD Flow
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 2
Basis of Flow Estimates
April 2016 2-4
The original future BWF projection was developed in 2009 as part of the City’s overall General Plan Update effort, in which over one thousand parcels with development potential were identified and their developments were quantified in terms of dwelling units (for residential developments) and/or building square footage (for non-residential developments). The development quantities were multiplied by the corresponding unit flow factors depending on land use to convert the information into BWF estimates.
These unit flow factors are summarized in Table 2-1.
Table 2-1: Base Wastewater Flow Unit Flow Factors
Type of Development Unit Flow Factor (1) Basis
Single Family Detached 245 gpd/DU 3.5 people/DU, 70 gpcd Townhouse or Condominiums 175 gpd/DU 2.5 people/DU, 70 gpcd Apartments 154 gpd/DU 2.2 people/DU, 70 gpcd
Hotels 100 gpd/room n/a
Commercial Offices 0.1 gpd/sq. ft. n/a
R&D Offices 0.15 gpd/sq.ft. n/a
1. All unit flow factors are consistent with factors used in the 2007 Capacity Assessment.
Parcels that were not identified with development potential were assumed to retain the same land use through 2035 and therefore also maintain approximately the same level of wastewater generation, which was developed based on their 2005-2006 winter water billing data. This version of the future BWF projection has since then been used for various capacity evaluations, and was updated regularly when new development or redevelopment project applications were submitted to the City for capacity evaluation.
In 2015, the City identified a number of additional developments that were not accounted for in the original General Plan Phase 3 development forecast prepared in 2009. The City also identified a list of parcels with entitlement agreements that allow the owners of these parcels to discharge wastewater up to a certain flow rate without applying for permission or notifying the City. Neither set of data was accounted for in the original projection. Furthermore, the revised existing BWF estimates are noticeably lower than those developed based on the 2005-2006 winter water billing data. The decline could be mostly attributed to increased water conservation activities in response to the recent drought. This is also evidenced in the City’s potable water sales records, which shows a sharp decline in the past ten years despite continuous population growth in the City. While it is possible that water use could rebound if and when the drought is over (e.g., behavioral changes such as reverting back to longer showers), some of the reduction is likely to remain permanent as a result of installing water-efficient plumbing fixtures and greater awareness of the need to continue conserving water.
In light of the various changes in water use and development information, a focused effort was undertaken to revise the City’s future BWF projections. Parcels that were identified to have development potential in the revised General Plan Phase 3 forecast were re-processed using the updated development quantities.
Parcels that were not identified with development potential were assumed to maintain their current water use, which is the updated existing BWF described in the previous section, instead of the original BWF based on previous 2005-2006 water use data, plus a 10 percent rebound factor to account for possible increase in water use in the future. For parcels that are on the list of development/redevelopment projects that the City has received between 2009 and 2015, their BWF was estimated according to the development quantities specified in their project applications. For parcels that hold entitlement agreements, BWF was set to their entitled flow rates.
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 2
Basis of Flow Estimates
April 2016 2-5
Table 2-2 summarizes the existing (circa 2015) and future (2035) BWF for residential and non-residential sectors. Based on these estimates, BWF is projected to increase by over two fold to 27.1 mgd in 2035.
Table 2-2: Base Wastewater Flow Estimates
Land Use Existing Flow
(mgd)
Future Flow
(mgd)
Residential 6.5 10.7
Non-Residential (1) 4.4 16.4
Total (2) 11.0 27.1
1. Does not include flow from the Levi’s Stadium, which varies greatly depending on the use of the venue; average flow on a peak game day is approximately 0.19 mgd based on flow monitoring conducted as part of this project.
2. Does not include flow from the Cupertino Sanitary District (CuSD), which is discussed in section 2.5.
2.2.3 Diurnal Curves
In most sewer systems, BWF typically exhibits distinctive diurnal patterns depending on the land use, usually categorized as residential, commercial, and industrial. For Santa Clara, flow monitoring data showed typical responses to commercial and industrial patterns, but also two residential patterns: the northeastern part of the City in the vicinity of Lafayette Street and Montague Expressway appeared to have a more pronounced morning peak flow and a lower evening peak, while the rest of the City had a less peaky morning peak and a somewhat higher evening peak. As such, two residential diurnal curves were created to represent these two patterns.
The diurnal curves are shown in Figure 2-3. Each subcatchment was assigned one of the residential curves according to its location (Lafayette Area vs. all other areas); and one of the non-residential curves according to the primary type of non-residential establishments (commercial or industrial).
Figure 2-3: Wastewater Diurnal Curves
Figure 5A: Typical Residential Flow Figure 5B: Lafayette Area Residential Flow
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Sanitary Sewer Master Plan Update
Chapter 2
Basis of Flow Estimates
April 2016 2-6
Figure 5C: Commercial Flow Figure 5D: Industrial Flow
Some of the City’s large water users do not exhibit typical diurnal curves. To ensure their flow patterns are accurately reflected in the model, nonresidential accounts with average water use of over 50,000 gpd were identified and individually researched. A total of 18 such large users were identified, and City staff contacted each user to collect operational information regarding their sewer discharge pattern. Individual diurnal curves were created for each based on the operational hours indicated on their wastewater discharge permits or surveys. These large water users are summarized in Table 2-3.
Table 2-3: City’s Large Water Users
Account Holder APN Address Est. Average
Flow (mgd)
Graphic Packaging Intl. Inc. 230-03-100 2600 De La Cruz Blvd. 0.587 Siliconix Inc. 104-39-023 2201 Laurelwood Rd. 0.405
Streamline Circuits Corp. 224-06-170 1415 Richard Ave. 0.308 Intel Corporation 104-48-010 3600 Juliette Ln. 0.191
Intel Corporation 216-46-015 3065 Bowers Ave. 0.099
Marvell Semiconductor Inc. 104-52-024 5488 Marvell Ln. 0.081 APCT Inc. 101-15-033 3495 De La Cruz Blvd. 0.074
Perkin Elmer Optoelectronics 104-13-083 2175 Mission College Blvd. 0.071 Owens Corning Sales LLC 224-07-099 960 Central Exp. 0.069 Applied Materials 216-49-024 3070 Bowers Ave. 0.067
Reaction Technology Inc. 104-51-001 3400 Bassett St. 0.067 City of Santa Clara – Electrical Dept. 230-03-067 524 Robert Ave. 0.065 Abbott Diagnostics Div. 104-50-016 5440 Patrick Henry Dr. 0.063 Diana Fruit Co. Inc. 224-40-001 651 Mathew St. 0.061
Oracle America Inc. 097-08-114 4100 Network Cl. 0.058
Digital 3011 Lafayette LLC 224-36-052 3011 Lafayette St. 0.053 Intel Corporation 104-39-020 2200 Mission College Blvd. 0.053 Agilent Technology 316-17-018 5301 Stevens Creek Blvd. 0.051
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Sanitary Sewer Master Plan Update
Chapter 2
Basis of Flow Estimates
April 2016 2-7
2.3 Groundwater Infiltration
Groundwater infiltration is generally quantified based on actual flow monitoring data, since it is difficult to predict GWI rates based on physical system data alone. In the context of design flow criteria, GWI represents the incremental groundwater infiltration that occurs during the wet weather season above the “baseline” infiltration level during the driest months of the year.
GWI can be estimated based on minimum flows during non-rainfall periods during a wet weather flow monitoring period. Minimum flows typical occur during the nighttime or early morning hours when base wastewater flows are at a low. Alternatively, GWI can be estimated as the difference between average metered flow during non-rainfall periods and computed average BWF. In either case, the resulting GWI, is expressed on a unit basis (gpd/acre or gpad) by dividing by the sewered acreage of the monitored area.
Typical GWI rates may range from about 100 to 1,000 gpad.
GWI were estimated through the model calibration process (described in Chapter 3) by comparing modelsimulated BWF to actual flow measurements from the temporary flow monitoring programs. Cases where model-predicted BWF was noticeably lower than monitored flow indicated the possible occurrence of GWI.
2.4 Rainfall-Dependent I/I
RDI/I flows result from rainfall events that produce infiltration and inflow of storm water into the sewer system. RDI/I can be quantified as the difference between the total flow during and immediately following a storm event and the non-rainfall “base flow” (BWF plus GWI) that is estimated to have occurred during the storm period. The magnitude of the resulting RDI/I response is typically described by the percentage of the rainfall volume (called the “R value”) represented by the volume of the RDI/I hydrograph. The R value can vary from storm to storm, depending on such factors as the degree of soil saturation (due to antecedent rainfall) prior to the storm event.
The shape of the RDI/I hydrograph is also important in determining the peak RDI/I response. The RDI/I hydrograph shape is often defined by separating the total RDI/I hydrograph volume into components, representing different response times to rainfall (fast, medium, and slow). Each component is identified by a percentage of the total RDI/I volume and specific time to peak (T) and recession coefficient (K), illustrated in Figure 2-4. The R component percentages and T and K values can be applied to each hour of rainfall to generate a “synthetic hydrograph” that approximates the volume and shape of the hydrograph from the actual observed event. These parameters, when applied to a different rainfall pattern, can be used to estimate the RDI/I response to that particular rainfall event. This methodology is used to synthesize RDI/I hydrographs for a “design storm” for collection system modeling (see Chapter 3 for discussion of design storms).
Design criteria for RDI/I include design R values and hydrograph shape parameters and the hourly rainfall for the selected design storm event. As described in the next chapter, R values and hydrograph parameters are determined through the process of model calibration, in which actual observed rainfall events are simulated in the hydraulic model, and the resulting model hydrographs are compared to the measured flows at flow meters locations. The RDI/I parameters are adjusted as needed to achieve the best match of modeled to monitored flows. Once calibrated, the model RDI/I parameters can be applied to a design storm to simulate wet weather flows for a design event.
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 2
Basis of Flow Estimates
April 2016 2-8
Figure 2-4: RDI/I Hydrograph Components
2.5 Flow from Cupertino Sanitary District
CuSD provides sewer collection services for the majority of City of Cupertino, portions of the City of Saratoga, and several unincorporated areas within Santa Clara County east of San Jose. Most of the flow is discharged into the Santa Clara system via a 27-inch sewer line in Homestead Road; the rest is discharged into the City of San Jose (CSJ) system at various other connection points.
CuSD maintains a permanent flow meter at its discharge point in Homestead Road. Meter data between November 2014 and March 2015 were reviewed and analyzed; the average dry weather flow (ADWF) was about 3.5 mgd. Similar to the declining trend observed for the City, CuSD’s flow has also declined over 28 percent from the 2007 estimates of 4.9 mgd to the current estimates of 3.5 mgd, most likely also due to increased water conservation activities in response to the recent drought.
Multiple meetings were held with City staff and CuSD staff to discuss development projections within the CuSD service areas in an effort to estimate the future BWF for the CuSD system. Information from sources such as the City of Cupertino’s General Plan 2020 and General Plan 2040, CuSD-SJ Joint Interceptor Cost Sharing Agreement (which indicates how much flow CuSD would be discharging into the San Jose system), ABAG projections, and CuSD meter data were discussed. Characteristics of the CuSD system, such as system age and I/I, planned sewer improvements, and known large development projects were also considered. Preliminary model simulations were conducted to understand the potential impact of the CuSD flow on the Santa Clara system under future peak design storm condition. For this Master Plan Update, City staff has directed RMC to use 6.90 mgd as CuSD’s future ADWF, and cap its future PWWF at 13.8 mgd, which is the maximum flow rate set forth in the agreement3 between the City and CuSD.
3 Agreement between the City of Santa Clara and the Cupertino Sanitary District for (a) the purchase of capacity in Cupertino’s sanitary interceptor sewer within the City of Santa Clara and (b) continued use by Cupertino Sanitary District of 13.8 MGD Peak Capacity in the City of Santa Clara’s interceptor sewer system.
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 3
Hydraulic Model Development
April 2016 3-1
Chapter 3 Hydraulic Model Development
This chapter describes the process of developing and calibrating the hydraulic model for use in the capacity assessment, including the flow monitoring program that was conducted for this study.
3.1 Modeling Terminology
Network refers to the representation of the physical facilities being modeled. The primary components of the modeled network are pipes, manholes, and pump stations.
Nodes are primarily manholes, but also include pump station wet wells, outfalls (discharge points of the modeled system) and breaks (changes in slope or diameter without a structure, such as at the vertical bends in inverted siphons). The primary data associated with nodes are rim and invert elevations. In the case of wet wells, the data also includes the diameter (for a circular well) or cross-sectional area.
Pipes are connections between nodes. The primary data associated with pipes are upstream and downstream node IDs, pipe length, diameter, and upstream and downstream invert elevations. Pipes include both gravity sewers and force mains.
Pumps are represented by links connecting the wet well node(s) and the discharge manhole or upstream end of the force main. Pumps are controlled by a number of user-defined parameters, including the switchon and switch-off levels, types of pumps, and head discharge curves.
Other model components include Gates and Weirs, which are represented by links with zero length.
Primary data associated with gates are the opening width and invert; data associated with weirs are the crest width and crest elevation.
Subcatchments are areas that contribute flow to the modeled sewer network and represent the unmodeled sewers in the collection system. Data associated with subcatchments include base wastewater (sanitary) flow (computed based on population, water use, or other available data), type of land use (which defines the diurnal profile associated with the base wastewater flow), infiltration/inflow (I/I) parameters, and the node at which the flow from the subcatchment enters the modeled system.
Loads are the flows assigned to each subcatchment. Components of model loads include residential and commercial base wastewater flow (BWF), groundwater infiltration (GWI), and rainfall-dependent I/I (RDI/I). As a sum, they represent the total wastewater flow applied to the model.
Models are the combination of a modeled network, its associated subcatchments and loads, and other data files (e.g., rainfall, diurnal profiles, etc.) that comprise a specific model scenario.
3.2 Delineation of Modeled System
A hydraulic model is typically developed to represent the trunk sewer system, which is the network of larger diameter pipes that comprises the “backbone” of the entire system. The City’s original hydraulic model was developed by RMC as part of the 2007 Capacity Assessment project and included approximately 28 percent (about 76 miles) of the total sewer pipelines and four of the pump stations. The model was originally constructed using modeling software MIKE URBANTM (SWMM version) and was converted to InfoWorksTM CS in 2008. RMC has continuously maintained and updated the model as sewer improvement projects were implemented or when new network data became available.
For this Master Plan Update, the model was expanded to include approximately 34 percent (about 92 miles) of the total pipelines and all seven pump stations. The force mains downstream of the Rabello and Northside pump stations were also added. A summary of the system’s pipeline inventory is provided in Table 3-1.
The modeled network is shown in Figure 3-1.
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Table 3-1: Sewer Collection System Model Summary
Pipe Diameter (in) Total Length1
(ft)
Length Modeled1
(ft)
Percent
Modeled
4-6 197,400 1,800 0.9%
8 619,600 48,300 8%
10 132,300 65,200 49%
12 224,900 120,300 53%
14-16 62,800 59,400 95%
18 43,700 42,000 96%
20-21 15,300 15,300 100%
24 49,600 49,600 100%
27 15,000 15,000 100%
30 25,900 25,900 100%
>30 38,100 38,100 100%
Force Main 13,000 13,000 100%
Total (feet) 1,437,600 493,900 34%
Total (miles) 272.3 93.5 34%
Approx. No. of Manholes 5,260 1,870 36%
No. of Siphons2 53 53 100%
1. Rounded to the nearest hundred feet.
2. This refers to the total number of barrels. Some siphons have multiple barrels.
All seven pump stations in the system are included in the model. A survey was conducted to collect information on pump curves and the operational sequences, as summarized in Table 3-2 below. Pump capacity analysis was conducted for all stations and the results are summarized in Chapter 4 of this report.
Table 3-2: Collection System Pump Station Summary
No. Station Name No. of
Pumps Description Emergency Bypass
1 Westside Lift Station 2 Identical Flygt 3127 pumps. Yes 2 Tasman Lift Station 2 Identical Flygt 3127 pumps. Yes 3 De La Cruz Lift Station 2 Identical Flygt 3127 pumps. Yes 4 Primavera Lift Station 6 Identical Flygt 3127 pumps. Yes 5 Stadium Lift Station 6
New lift station completed in 2014. Two
identical low-flow pumps (Flygt 3127) and
four identical high-flow pumps (Flygt 3153).
Yes
6 Rabello Pump Station 8 Identical Flygt 3202 pumps. Four new pumps installed in 2013 and in 2014. Yes
7 Northside Pump Station 4 Four identical Flygt 3356 pumps. Yes 0 0.5
1 Mile µ Legend
Modeled Trun k Sew ers
≤ 6"
8" - 10"
12" - 16"
18" - 24"
≥ 27"
ÉP Modeled Pum p/Lift Station
Un m odeled Sew ers
San Jose In terceptors
City Lim it
J:\Projects\149 SANTA CLARA\149-008 San ta Clara 2015 San itary Sew er MP Update\G. GIS Files\_MX Ds\Master Plan Report Figures\MPFig3-1_ModeledNtw k_05Apr2016.m xd City of San ta Clara
San itary Sew er
Master Plan Update
Figure 3-1
Modeled Trunk System
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 3
Hydraulic Model Development
April 2016 3-4
Flows are loaded into the model at “loading manholes,” each representing the point where flows from adjacent parcels or parcels connected to unmodeled sewers discharge to the modeled network. The parcels connected to unmodeled sewers were grouped into sewer subcatchments based on the modeled manhole to which the unmodeled sewers drain. Each subcatchment was associated with a unique load manhole in the model network. Approximately 860 sewer subcatchments and associated loading manholes were delineated for defining the model loads. The subcatchments and load manholes are shown in Figure 3-2.
3.3 Model Network Construction and Validation
Data of the expanded network were compiled from available as-built drawings, field measurements, and Excel files from previous modeling efforts. The network was also validated using the following steps:
The entire modeled network (both the original network and the expanded portion) was checked for connectivity, i.e., verifying that correct upstream/downstream manholes were identified for each pipe and there were no missing links in the network.
Profiles were plotted for each series of pipe segments to visually check for missing or suspect data, such as missing rim or invert elevations, negative pipe slopes, or abrupt steps up or down in pipe inverts.
Where appropriate, data were interpolated or verified through field investigation or as-built drawings. As-built drawings and field data were used to develop details for the modeled pump stations, such as wet well elevations and dimensions, number of pumps, pump types, on/off levels, and discharge curves. Flow splits (manholes with more than one outlet pipe) were identified, and field verification and/or asbuilt drawings were requested as needed for further verification of outlet pipe elevations and/or the existence of weirs or other flow diversion structures.
3.4 Flow Monitoring Program
Flow monitoring was conducted between November 2014 and March 2015 to measure actual flows in the system for analysis and calibration purposes. The monitoring was conducted by V&A Consulting Engineers (V&A) as subcontractor to RMC. The flow monitoring program originally consisted of 23 flow meters and four rain gauges. Most of the meters were installed and operational from December 10, 2014 to March 4, 2015 (approximately 12 weeks). Four of the meters, Meters 1 through 4, were installed earlier on November 22, 2014 to collect data during scheduled game events at the new Levi’s Stadium.
Factors that were considered in selecting the flow meter sites included:
Location of sites used in 2006 flow monitoring program for the City’s previous sewer system capacity assessment study
Similar sized tributary areas
Ability to isolate areas to characterize flows for model calibration Provides more specific information about flow splits
Preferred hydraulic conditions (i.e., manholes on a straight line preferred over manholes on bends or with multiple incoming pipes)
Ease of access and safety considerations
In addition to the 23 sites, the City also owns and maintains two permanent flow meters at the Guadalupe Chart Station just upstream of the connection with the City of San Jose’s Interceptors. Upon review of the data collected at these two meters, it was determined that a field calibration was necessary. V&A performed field calibration, and also installed two temporary flow meters at the same site to verify and ensure data quality of the two permanent meters.
The flow monitoring sites are listed in Table 3-3 and shown on Figure 3-3. A flow meter schematic is shown on Figure 3-4. Four rain gauges were installed to collect representative rainfall data over the service area during the monitoring period. The rain gauge locations are also shown on Figure 3-3.
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April 2016 3-5
Table 3-3: Summary of Flow Monitoring Sites
Meter
ID Location Manhole ID
Pipe Size
(in)
Avg.
Flow (1)
(mgd)
Peak
Flow (2)
(mgd)
1 (3) Lafayette St. north of Calle de Mundo S104-28 36 3.91 7.95 2 (3) Golf course private road west of Lafayette St. S104-26 33 3.97 8.36 3 (3) Lafayette St. north of Calle de Mundo S104-30 42 3.05 9.24 4 (3, 4) Parking lot of the new Levis Stadium S94-35 24 0.22 0.94 5 Mission College Blvd. north of Our Lady’s Wy. S83-21 33 3.97 10.3 6 Mission College Blvd. north of Our Lady’s Wy. S83-22 30 2.60 6.37 7 Upstream of Primavera Lift Station. S105-34 24 0.89 1.81 8 Lafayette St. north of Montague Expwy. S86-12 30 1.79 4.80 9 Calabazas Creek south of Kifer Rd. S62-40 24 1.98 6.34 10 San Juan Ave. and Monroe St. S52-79 24 0.80 2.80
11 Chromite Dr. and Pilot Knob Dr. S53-40 24 1.06 4.76
12 Chromite Dr. and Alhambra S53-23 24 1.19 4.74
13 Bowers Ave. just north of Bonnie Dr. S53-54 30 3.50 7.22 14 South Dr. south of Loma Vista Ln. S54-16 15 0.53 1.12 15 Nvidia Parking lot, west off of Scott Blvd. south of Central Expwy. S65-50 18 0.45 1.44
16 Central Expwy west of UPRR S67-13 27 1.43 2.70
17 De La Cruz Blvd. north of Martin Ave. S58-9 24 0.40 1.48 18 De La Cruz Blvd. north of Martin Ave. S58-8 24 1.14
19 North of intersection of Wren Ave. at Kent Avenue S21-18 24 1.63 3.13 20 Homestead Rd. west of Cherry Orchard Place S21-47 18 1.74 4.00 21 Kiely Blvd. south of Kaiser Dr. S23-6 24 2.25 3.68
22 Los Padres Blvd. at Bray Ave. S45-80 18 0.76 4.60
23 Brokaw Rd. north-east of UPRR S48-31 18 0.58 1.81
M1 (5) Guadalupe Chart Station East Line N/A 33 (6) 3.89 5.80 M2 (5) Guadalupe Chart Station West Line N/A 33 1.07 2.64
1. Average flow during non-rainfall period in mid- to late January.
2. Peak 15-minute flow during flow monitoring period (during December 11-12, 2014 storm event for most meters)
3. Meters 1 through 4 were installed on November 22, 2014. All other meters were installed on or around December 10, 2014.
All meters were removed on or around March 4, 2015.
4. Average flow represents a typical non-game day flow; peak flow represents a game day flow.
5. Meters M1 and M2 were installed starting January 9, 2015 in addition to the two permanent meters at the Guadalupe Chart Station.
6. Field measurements and observation show this line to be a 36-inch pre-fabricated T-lock lined pipe, while design drawings show its diameter to be 33 inches. A research was done to verify the pipe diameter but did not reach a conclusive result. As such, this pipe remains a 33-inch in the model.
0 0.5
1 Mile
Legend !( Loading Manholes
µ
ÉP Modeled Pump/Lift Station
Modeled Trunk Sewers
Unmodeled Sewer
San Jose Interceptors
Subcatchment
City Limit
J:\Projects\149 SANTA CLARA\149-008 Santa Clara 2015 Sanitary Sewer MP Update\G. GIS Files\_MXDs\Master Plan Report Figures\MPFig3-2_NtwkSubs_05Apr2016.mxd City of Santa Clara
Sanitary Sewer
Master Plan Update
Figure 3-2
Subcatchments and
Loading Manholes
0 0.5
1 Mile
Legend !( Flow Monitoring Site & ID
µ
Õ Rain Gauge Site and ID ÉP Modeled Pump/Lift Station
Modeled Trunk Sewers
Unmodeled Sewer
San Jose Interceptors
City Limit
J:\Projects\149 SANTA CLARA\149-008 Santa Clara 2015 Sanitary Sewer MP Update\G. GIS Files\_MXDs\Master Plan Report Figures\MPFig3-3_FM&RGs_05Apr2016.mxd City of Santa Clara
Sanitary Sewer
Master Plan Update
Figure 3-3: Flow Meter
and Rain Gauge Locations
20-26
21-49
10-29 11-41
15”@
126.8’
15”@
127.4
Gate 1
Gate 2
103-22 103-23
93-53
83-17
104-21
33”@-8.14
33”@-7.89
104-22
Calle PS
Westside PS
93-36
Tasman PS
33”@-2.61
93-52
33”@2.32
83-18
33”@6.89
73-7
21”@
19.76 18”@
19.98 73-30
63-20
53-34
62-6
62-8
62-10
53-105
10”
@40.9
62-5
15”@27.37
12”@31.06 21”@27.76
15”@31.01
61-17
61-16
73-29
8”@40.77+6”@43.47
52-4
32-102
ECR siphon
10”@76.16
32-101
15”@75.23 32-8
32-45
15”@75.45 33-33 33-34
15”@83.23
15”@82.83
12”@91.73
15”@91.53
32-68
15”@75.45
12”@113.06 22-55
21”@
100.23
10”@100.23
22-64
22-52
23-14
33-63
10”@131.94
23-27 24-32
10”@131.89
15”@
109.91 12”@
94.62 18”@
90.32 23-24
33-5
15-13
25-85
34-6
104-35
104-37
64-34
57-54
58-12
65-30
58-21
58-11
58-22
57-37
58-23
48-2
47-54
35-2
47-58
Trimble to
San Jose Interceptor
36-83
47-59
47-77
48-3
48-11
12”@
65.32 38-5
38-4
24”@
32.8 15”@
56.37 12”@
58.15 15”@
57.55 12”@
63.77 24”@35.52
48-48
24”@
28.91 57-57
38-14
37-48
12”@
58.89 15”@30.51
48-38
47-30
18”@37.07
58-3
68-23
18”@33.15
18”@33 18”@32.9
30”@
25.75 18”@26.75
68-20
33-4
27”@65.78
12”@72.03
64-41
25-9
64-46
64-44
64-45
105-37
104-33
105-35
105-6
21”@-11.15
21”@-11.15
105-7
105-36
18”@-2.7 15”@-2.71
104-49
104-31
105-27
24”@-9.19
12”@-9.04
22 6
4 3
2 Figure 8: City of Santa Clara Trunk Sewer System Schematic Last Updated: April 4, 2016
De La Cruz PS
1 # 2015 Flow Monitoring Sites
City’s Permanent Meters
Pump Station
Flow Split Manhole
Junction Manhole
Rabello PS
104-19
Northside PS
Santa Clara
Influent Structure 1
(San Jose)
52-65
10 41-104 10”@83.48
10”@
84.16 42-104 10”@78.98
10”@78.98
20-9
5 9
11 12 13
17 18
23 12”@
71.33 12”@
71.48 15
15”@
129.78
27”@
129.28
20-16
19 20
14 Walsh Line
M
M2
M1
97-10
Flow Diversion Structure (e.g., weir)
Stadium PS
86-20
New MH
16 21
8 7
Flow Direction
High‐Level Overflow
63-33
54-101
54-100
15”@
36.45 12”@
36.45 64-32
41-125
41-113 41-121
41-123
42-125
12”@
39.6 27”@
37.82 M
Santa Clara
Junction Structure
M
42”
42”
36”
42”
Control
Chamber
48”
36”
36”
48” FM
D
C
B
A
E
SJ Interceptors
M
24-62
13-38
13-27
13-55
12-50
23-51
23-28
26-44
35-42
26-70
35-20
35-37
35-25
35-17 35-87
36-1
47-60
47-32
47-55
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April 2016 3-9
During the flow monitoring period, all of the monitoring sites and the two permanent meter sites at the Guadalupe Chart Station were visited approximately biweekly to check meter operation and site conditions, obtain field calibration measurements, and download collected data. Field calibration involves taking manual depth measurements and flow velocity measurements using a portable velocity meter. These calibration measurements were compared to and used to adjust monitor-recorded depth and velocity if needed. Calibration measurements were taken at different times of day in order to obtain calibration points for the full range of typical diurnal flows.
Approximately four storm events occurred during the flow monitoring period. The biggest event occurred on December 11, 2014, in which over 3 inches of rainfall were recorded within a 24-hour period, with a peak hour rainfall of 0.38 inch between 9 a.m. and 10 a.m. This is the event used for wet weather flow calibration, discussed further in Chapter 3.
Plots of the flow monitoring data and a tabular summary of daily average, minimum, and maximum flows for each meter are included in Appendix A.
3.5 Model Calibration
Model calibration is the process of comparing model-computed flows to observed (monitored) flows to verify that the model is accurately simulating flows in the sewer system. As described above, temporary flow monitoring programs consisting of 25 flow meters installed in the Santa Clara system during the 2014/15 winter season as part of the study. The data collected during this flow monitoring program were used for model calibration.
3.5.1 Dry Weather Calibration
The 14-day non-rainfall period from January 17 to January 30, 2015 was used for dry weather calibration.
The dry weather calibration process was used to verify BWF loads and diurnal curves, and to quantify GWI (as indicated by monitored flows that were higher than estimated BWF). Table 3-4 compares the model vs. metered average dry weather flow (ADWF) at each of the meter locations. Figure 3-5 shows an example plot of model vs. metered flow for one of the flow monitoring locations in the system (Meter 5). Dry weather calibration graphs for all meters are included in Appendix B.
Overall, the model calibration resulted in a reasonably good match at most locations, but there were differences at some locations. These differences may be due to inaccuracies in the meter data, water use loadings, or configuration of the system (e.g., upstream flow splits, weir settings, etc.). Extensive effort was made to resolve as many of the calibration differences as possible. As shown in Table 3-4, the sum of the observed flows at the most downstream meters (Meters 1, 2, 3, M1 and M2) was within 6 percent of the modeled flows, which provides confidence that the overall flows in the model are reasonably accurate.
Note that the total model ADWF is higher than the estimated existing BWF shown in Table 2-2 because the model ADWF also accounts for the CuSD flow (observed flow data was used, which was approximately
3.57 mgd for the calibration period) and about 0.35 mgd of GWI that was added to the system during the calibration process, which was applied to the basins tributary to meters 10 and 11, at an estimated rate of 1,000 gpd/acre. As described in Chapter 2, GWI is calculated based on the difference between average flow on non-rainfall days during the flow monitoring period and estimated BWF for meters for which estimated BWF is noticeable lower than monitored flow. Other meter areas may also include some nominal dry weather GWI, which is assumed to be included in the BWF estimates.
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Table 3-4: Dry Weather Flow Calibration Results
Meter ID Meter
Avg. Flow (mgd)
Model
Avg. Flow (mgd)
Difference
(mgd)
Percent
Difference
1 3.91 3.42 -0.49 -12%
2 3.97 3.71 -0.26 -7%
3 3.05 3.27 0.21 7%
4 (1) 0.22 0.22 0.00 0%
5 3.97 3.99 0.02 0%
6 2.60 2.54 -0.06 -2%
7 0.89 0.74 -0.16 -17%
8 1.79 1.70 -0.09 -5%
9 1.98 2.25 0.27 13%
10 0.80 0.80 0.00 0%
11 1.06 1.10 0.04 4%
12 1.19 1.14 -0.05 -4%
13 3.50 3.59 0.09 3%
14 0.53 0.51 -0.02 -4%
15 (2) 0.45 0.81 0.36 79%
16 (2) 1.43 1.06 -0.37 -26%
15 & 16 (2) 1.88 1.87 -0.01 -1%
17 0.40 0.54 0.14 34%
18 1.14 0.99 -0.15 -13%
19 1.63 1.56 -0.07 -4%
20 1.74 1.51 -0.23 -13%
21 2.25 2.09 -0.15 -7%
22 0.76 0.91 0.14 19%
23 (3) 0.58 0.69 0.11 18%
M1 (Guadalupe East) 3.89 3.41 -0.48 -12%
M2 (Guadalupe West) 1.07 1.16 0.09 8%
Sum of D/S Meters (4) 15.90 14.97 -0.92 -6%
1. Meter 4 was installed immediately downstream of the Levi’s stadium with the intention to collect data to study flow patterns during major game events. The meter did capture good flow data for a number of game events, but also encountered a technical issue in late January that caused data collected between January 20 and February 18 (overlapping with the calibration period) to be unrecoverable. As such, data collected between January 11 and January 18 (a 7-day non-rainfall period when the venue was not used for any games) was used to establish the baseline flow for the stadium.
2. Meters 15 and 16 had an unexpected shift in flow distribution between late December 2014 and early January 2015, possibly caused by a temporary blockage upstream of the two meters. City staff was informed of this shift but could not provide an explanation. Although the meter flows did return to a higher level in late January 2015, they never returned to the pre-shift level. As such, their data was deemed not suitable to be used for calibration for each meter basin individually; instead, their tributary subcatchments were calibrated together as one basin using the combined data of the two meters.
3. Meter 23 was located downstream of the Santa Clara University. The dry weather calibration period coincided with the registration week of the school’s winter quarter when student population was not at its maximum. The observed flow for this meter was therefore noticeably lower than the modeled flow (which was developed based normal school period).
4. Downstream (D/S) Meters are meters 1, 2, 3, M1, and M2. See system schematic in Figure 3-4.
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Figure 3-5: Example Dry Weather Calibration Graphs
3.5.2 Wet Weather Calibration
The storm that occurred on December 11, 2014 was used for wet weather calibration. As described previously, RDI/I response to rainfall events was quantified in terms of three sets of triangular unit hydrograph parameters that represent the volume percentage of rainfall that enters the system as RDI/I and the shape of the RDI/I hydrograph as a function of each hour of rainfall. Through the wet weather calibration process, RDI/I hydrograph parameters were developed for each meter area. In general, the response to rainfall in the Santa Clara system is relatively small, as evidenced by the relatively low peak flow response to the rainfall event, with the exception of areas in the western portion of the City near Monroe Street, which showed both a high peak inflow during the rainfall event and an extended period of infiltration after the event.
Table 3-5 lists the “R values” (as percentages of rainfall) for each flow meter area. Figure 3-6 shows an example plot of model vs. metered flow for one of the flow monitoring locations in the system (Meter 5).
A complete set of wet weather calibration graphs of modeled vs. metered flow for all meter locations are included in Appendix C.
Obs.
...n Runs>DWF_1/17/2015+14D (w/GWI)>DWF
Flow (MGD)
Min
1.390
1.380
Max
6.323
6.119
Volume (US Mgal)
55.644
55.886
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Table 3-5: Wet Weather Flow Calibration Results
Meter ID R1 RDI/I Vol. (%) R2 RDI/I Vol. (%) R3 RDI/I Vol. (%) Total R (%) 1 0.3% 0.3% 0.8% 1.4%
2 0.1% 0.5% 0.8% 1.4%
3 0.1% 0.1% 0.1% 0.3%
4 1.0% 0.1% 0.1% 1.2%
5 0.1% 1.0% 1.5% 2.6%
6 0.1% 0.5% 1.5% 2.1%
7 0.2% 0.5% 0.8% 1.5%
8 0.3% 0.5% 1.2% 2.0%
9 0.5% 3.5% 8.0% 12.0%
10 1.0% 4.2% 8.0% 13.2%
11 0.1% 2.0% 15.0% 17.1%
12 0.2% 1.0% 20.0% 21.2%
13 0.1% 0.1% 0.8% 1.0%
14 0.4% 0.1% 0.5% 1.0%
15 & 16 (1) 0.1% 0.1% 0.3% 0.5%
17 0.5% 0.5% 0.5% 1.5%
18 0.5% 0.8% 1.0% 2.3%
19 0.3% 0.4% 0.5% 1.2%
20 0.1% 0.1% 0.1% 0.3%
21 0.2% 0.1% 0.1% 0.4%
22 0.1% 0.2% 0.1% 0.4%
23 0.5% 0.2% 0.1% 0.8%
CuSD 0.25% 0.35% 0.5% 1.1%
1. Meters 15 and 16 were calibrated together due to unexpected field conditions. See note 2 under Table 3-4.
City of Santa Clara
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Chapter 3
Hydraulic Model Development
April 2016 3-13
Figure 3-6: Example Wet Weather Calibration Graphs for 2014 Storm Period Rain
Obs.
...Rainfall Event (11/18-3/05)
Rainfall
Depth (in)
4.990
Peak (in/hr)
1.280
Average (in/hr)
0.019
Flow (MGD)
Min
1.319
1.515
Max
10.323
9.470
Volume (US Mgal)
53.945
52.096
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Sanitary Sewer Master Plan Update
Chapter 4
Capacity Analysis
April 2016 4-1
Chapter 4 Capacity Analysis
This chapter describes the hydraulic analysis and design criteria used to evaluate system performance and size capacity relief projects, the capacity deficiencies based on the results of model runs, and preliminary solutions to identified capacity deficiencies. The chapter also summarizes the pump station capacity evaluation and analysis.
4.1 Design Event Criteria
Peak design flows for sewer systems consist of dry weather base wastewater flow (BWF), groundwater infiltration (GWI), and rainfall-dependent infiltration/inflow (RDI/I). Criteria for computing existing BWF, GWI, and RDI/I (developed as part of model calibration), and unit flow assumptions for future development were discussed in the previous chapters. However, the peak design flow criteria must also specify the set of conditions (e.g., design storm rainfall and timing with respect to seasonal GWI and diurnal BWF) that will generate the highest peak flows that the sewer system must be capable of hydraulically conveying.
The following subsections discuss design storm criteria, present data from recent storm events, and identify options and recommendations for selection of a design event for use in this Master Plan Update.
4.1.1 Design Storm Condition
The use of wet weather design events as the basis for sewer capacity evaluation is a well-accepted practice.
The approach is to first calibrate a hydraulic model of the system to match wet weather flows from observed storms, and then apply the calibrated model to a design rainfall event to identify capacity deficiencies and size improvement projects. The design event may be synthesized from rainfall statistics, or may be an actual historical rainfall event of appropriate duration and intensity.
A design storm is used to simulate a peak wet weather flow condition to identify system deficiencies and develop solutions for them. Design storms are typically classified by their return period and duration. The return period defines the probability that the design rainfall will be exceeded in any given year. For example, a storm with a 10-year return period means there is a 1 in 10 chance, or 10 percent probability, of exceeding the design rainfall in a given year. The chosen return period reflects the degree of risk an agency will tolerate of experiencing sanitary sewer overflows (SSOs) due to future storm events. However, choosing a design storm with a very high return period (reflecting a very low risk tolerance) could lead to the identification of so many system capacity deficiencies that the cost of improvements is prohibitive. Additionally, sizing a system for a very rare event could mean that the system does not function well under typical conditions during much lower flows (due to slow velocities in oversized pipes, or oversized pump stations).
A storm duration must be specified along with the return period. Most Bay Area agencies use a 24-hour storm, though shorter or longer durations may sometimes be appropriate depending on system size and how quickly or slowly the system responds to rainfall. Design storm may be actual historical rainfall events or synthetic events that are designed to represent a certain return period for a specified storm duration or durations.
The City’s 2007 Capacity Assessment used a 10-year, 24-hour storm, with one-hour and six-hour 10-year events included within the 24-hour event. This storm was based on the Santa Clara County intensityduration-frequency (IDF) curve that was current at the time, representing rainfall statistics at the San Jose International Airport. To reflect differences in rainfall characteristics across the service area, the storm was scaled for different areas based on the isohyetal map of average annual rainfall from the Consoer, Townsend & Associates Sanitary Sewer I/I Analysis, dated 1974.
Since the completion of the Capacity Assessment, Santa Clara County released a new County Drainage Manual in October 2007. The Manual includes updated mean annual precipitation isohyetal lines from Santa Clara Valley Water District (SCVWD) and updated, distinct IDF curves for each mean annual City of Santa Clara
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Capacity Analysis
April 2016 4-2
precipitation area. In addition to the IDF curves, Appendix D of the 2007 manual includes a 24-hr design storm pattern. According to the manual, this storm pattern is based on an actual event that occurred in December 1955, but with some adjustments to better reflect IDF statistics for various storm durations. Like the previous design storm, the design storm used for this Master Plan Update is also a 10-year, 24-hour storm that varies across the service area, but the storm pattern and hourly rainfall intensities are based on this updated Santa Clara County Drainage Manual. Figure 4-1 shows the design storm hourly rainfall as it occurs in the vicinity of the San Jose International Airport. At this location, the total rainfall for the 1, 6-, and 24-hour durations is 0.65, 1.49, and 2.92 inches, respectively.
Figure 4-1: Design Storm Pattern for the San Jose International Airport MAP Area The design storm represents the “point precipitation” at any single location in the system. The storm is applied in the model at the subcatchment level, with the assumption that the rainfall occurs simultaneously on all subcatchments, which is a conservative assumption.
As noted previously, the timing of the design storm also affects the resulting peak wastewater flows. If the design storm is timed to cause peak RDI/I at the same time as peak base wastewater flow, the total peak wet weather flow will be higher than if the design storm occurs during minimum or average base wastewater flow. Due to variations in the diurnal flow patterns as well as variations in the calibrated I/I response throughout the system, it is not possible to time the rainfall to create a peak-on-peak response everywhere in the system. However, the design storm was timed to achieve a peak-on-peak response in most areas of the system, with the peak hour rainfall occurring at 8:00 a.m. on a weekday.
4.2 Hydraulic Capacity Criteria
The hydraulic capacity criteria determine which sewer pipes should be relieved or replaced due to inadequate capacity to convey existing or future peak flows, and how large the new sewers should be. The criteria adopted by the City should ideally be stringent enough to ensure that sewer overflows caused by capacity limitations (as distinguished from other causes such as obstructions or structural failures) are very rare occurrences, but not so conservative that they cause the City to spend capital improvement funds unnecessarily or result in pipes that are so large that cleaning velocities cannot be achieved under normal flow conditions, causing solids build up and related problems.
The capacity deficiency criteria identify the need to replace an existing facility, while design criteria determine the sizing of new facilities. These criteria are discussed in the paragraphs below. 0 0.1
0.2 0.3
0.4 0.5
0.6 0.7
0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00 Rainfall Intensity (in/hr)
Hour
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Chapter 4
Capacity Analysis
April 2016 4-3
4.2.1 Capacity Deficiency Criteria
The capacity deficiency criteria are used to determine when the capacity of an existing sewer facility is exceeded to the extent that a relief sewer or larger replacement sewer or potential pump station capacity upgrade is required. Capacity deficiency criteria are sometimes called “trigger” criteria in that they trigger the need for a capacity relief project. These criteria often differ from criteria that are applied to determine the size of a new facility, which are typically more conservative.
It is important that the capacity deficiency criteria be coordinated with the peak design flow criteria. For example, if the peak design flow were to be based on only peak dry weather flow (PDWF), the deficiency criteria would need to be conservative (e.g., require pipes to flow less than full to allow capacity for I/I).
On the other hand, if the peak design flow includes I/I from an infrequent storm event, it may be appropriate to allow the sewers to flow surcharged to some extent, since the peak flows will be infrequent and brief in duration.
Gravity Sewers
Since the peak wet weather design flow as recommended in the previous section of this chapter includes RDI/I from a 10-year return period event and is assumed to be concurrent with peak BWF, the City should consider it acceptable to allow gravity sewers to flow surcharged to some extent before a capacity relief project is triggered. For example, significant surcharging may be acceptable in larger, deeper sewers provided the hydraulic gradeline remains a reasonable distance below the ground surface and no surcharging occurs during dry weather flow conditions. For smaller or shallow sewers, a more conservative criteria could be considered to account for the chance that capacity could also be compromised by factors such as offset joints, roots, grease, and debris (which cannot be accounted for in the hydraulic model), or that surcharge could result in flow backing up into connecting laterals.
Based on discussion of these considerations, the following criteria are proposed under which gravity sewers would be considered capacity deficient:
PDWF: No surcharge allowed (d/D ≤ 1.0)
PWWF:
o Gravity sewer with less than 6 feet of cover: no surcharge allowed (i.e., d/D ≤ 1.0) o Gravity sewer with 6 feet or more of cover: surcharge of up to 1 foot under PWWF (see Figure 4-2 for clarification)
Case-by-case exceptions could be made for isolated short pipe reaches. Conversely, more stringent criteria could be applied for sewers located in areas where the consequences of an overflow would be greater (e.g., adjacent to creeks, schools, or hospitals). Note that for evaluating the performance of existing sewers, a Manning’s “n” value of 0.013 is assumed for all pipes, regardless of material or age. Although new pipes, particularly plastic materials, would provide a lower initial roughness factor, it is assumed that over time, a “slime layer” formation on the walls of the pipes and/or other obstructions in the sewer, such as roots, debris, or structural defects, may increase pipe roughness. Therefore, an assumption of 0.013 for all pipes is considered to be appropriately conservative for master planning purposes.
Pump Stations and Force Mains
For master planning capacity assessments, the performance of pump stations and force mains are typically evaluated based on pumping capacity and peak force main velocities. Pump stations are considered to be capacity deficient if the station’s firm capacity (capacity with largest pumping unit out of service) is insufficient to convey the peak design flow. Force mains are considered to be deficient if velocity under peak design flow exceeds 10 feet per second (fps).
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Figure 4-2: PWWF Hydraulic Deficiency Criteria for Gravity Sewers Scenario A:
Shallow Pipe (cover less than 6 feet)
Criteria: d/D ≤ 1.0
Scenario B:
Deep Pipe (cover of or more than 6 feet)
Criteria: Surcharge ≤ 1.0 foot
4.2.2 Sizing Criteria for New Sewer Facilities
The following criteria are proposed for sizing new trunk gravity sewers as part of the Master Plan. They are consistent with the City’s current sanitary sewer design criteria. Note that the City may use somewhat different criteria for new developments or actual design, e.g., varying Manning’s n for different pipe materials, or a more conservative d/D for smaller diameter sewer mains. These criteria would be based on the modeled design storm peak wet weather flows in the system. Maximum allowable flow depth-to-diameter ratio (d/D) of 0.75 under peak design flow A Manning’s ‘n’ of 0.013
Minimum pipe size of 8 inches diameter in residential areas; 10 inches in commercial areas; and 12 inches in industrial areas
Minimum velocity of 2 feet per second (fps) at half-full pipe Maximum velocity of 10 fps at peak design flow
Downstream pipes at least as large as upstream pipes
Minimum and maximum pipe slopes determined based on above velocity criteria to the extent feasible (it is recognized that elevation constraints in the existing system may prevent achieving desired minimum slopes for some projects, and terrain may dictate higher maximum slopes in some cases)
Minimum pipe cover of 6 feet
Gravity Sewer
D
d
Cover (<6’)
Freeboard (≥5’)
Cover (≥6’)
Surcharge (≤1’)
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4.3 Capacity Analysis Results and Proposed Solutions
Based on the criteria described above, the hydraulic model was run for four sets of conditions representing combinations of existing or future development and dry weather flow or design storm wet weather flow.
Figure 4-3 shows the model results for future PWWF conditions. Pipes shown in red are predicted to be surcharged due to “throttle” (peak flow exceeding full pipe capacity), and pipes shown in blue are surcharged due to backwater from a downstream throttle condition. Locations of capacity criteria violations (surcharge of more than 1 foot due to either throttle or backwater conditions) are highlighted in yellow (pipes with criteria violations under both existing and future conditions) or orange (future conditions only).
Note that the locations of criteria violations (i.e., higher than allowable surcharge) are not necessarily the locations of the actual capacity-deficient pipes, but are typically located further upstream due to backwater from downstream throttle conditions. Appendix D includes model hydraulic profiles for each of these areas.
Potential solutions for the identified capacity deficiencies were developed in order to assess the potential extent of required capacity improvements and to estimate the resulting peak flow to the SJ/SC RWF once capacity deficiencies are relieved. Table 4-1 summarizes the predicted flow under each condition. Table 4-2 describes the solutions. The solutions model results indicate that the combined total estimated design storm future PWWF from the City’s system (including flows from CuSD) would be approximately 59 mgd.
Table 4-1: Summary of Capacity Analysis Results
Existing
ADWF (2)
(mgd)
Existing
PDWF (2)
(mgd)
Existing
PWWF (3)
(mgd)
Future
ADWF (2)
(mgd)
Future
PDWF (2)
(mgd)
Future
PWWF (3,4)
(mgd)
Flow Estimates by System Outfall (1)
North (to Northside and Rabello
Pump Stations) 10.2 15.2/16.0 27.9 24.6 33.5/34.4 41.0
East (to San Jose Zanker Road
Interceptor) 4.7 6.4 11.7 9.8 13.3 18.3
Total 14.9 21.6/22.4 39.6 34.4 46.8/47.7 59.4
Flow Estimates by Agency (1)
Santa Clara System 11.3 15.4/16.2 26.8 27.5 34.6/35.5 45.6 Cupertino Sanitary District 3.5 6.2 12.8 6.9 12.2 13.8
Total 14.9 21.6/22.4 39.6 34.4 46.8/47.7 59.4
1. Assuming that trunk sewer capacity deficiencies are relieved with recommended capital improvement projects presented in Table ES-2.
2. Includes groundwater infiltration for a typical wintertime period. ADWF and first value shown for PDWF includes typical nongame day flow from Levi’s Stadium; second value shown for PDWF includes a peak game day flow from Levi’s Stadium.
3. For 10-year design storm; assumes non-game day flow from Levi’s Stadium.
4. Assuming peak wet weather flow from CuSD would not increase above its contractual maximum flow of 13.8 mgd.
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April 2016 4-6
Table 4-2: Capacity Deficiencies and Proposed Solutions Def.
ID
Deficiency
Location (1)
Trigger
Scenario Surcharge or Criteria Violation (2) Proposed Solution 1 Westside Lift Station 2015 PDWF
Current set point of the lead pump is about 5 feet above the invert of the influent line, causing backup issues upstream between MH S102-3 and S103-8 (station wet well).
Adjust the set point of the lead pump to be equal or lower than the invert of the influent gravity line. 2 Tasman Lift Station 2015 PDWF
Current set point of the lead pump is about 2 feet above the invert of the influent line, causing backup issues upstream between MH S93-24 and S93-35 (station wet well).
Adjust the set point of the lead pump to be equal or lower than the invert of the influent gravity line. 3 Cabrillo Avenue 2015 PWWF
Surcharge of up to 5 feet from MH S41-13 to S41-20 under existing PWWF scenario and potential overflow in S41-13, S41-14 and S41-15 under future PWWF scenarios.
Conduct smoke testing and television inspection in the flow tributary area to identify and address high inflow/infiltration sources. If field investigations indicate that I/I reduction is not feasible or cost-effective, then upsize the existing 8-inch line to a 12-inch between S41-13 and S41-20. 4 Tasman Drive and Old Ironsides Drive 2035 PWWF Surcharge of up to 3 feet upstream of Tasman Lift Station. Upsize 800 feet of existing 12-inch line between S93-24 and S93-35 to a 15-inch line. 5 Scott Blvd. 2035 PWWF Surcharge of up to 1 foot between S25-78 and S26- 44, and S26-57 and S25-37. Install a weir in S25-85 to divert flow northwest to Los Padres Blvd. 6 Calabazas Creek Trunk Sewer 2035 PWWF Surcharge of up to 3 feet in the existing 24-inch line along Calabazas Creek between S52-52 and S62-14. Install a new 200-ft 15-inch line between S42-12 and S52- 93 (Calabazas Blvd. and Machado Ave.) to partially divert flow from the 24-inch to the 21-inch on Machado Ave. 7 Tracy Dr., Pomeroy Ave., and Homestead Rd.
2035
PWWF
Surcharge and potential overflow between S10-77 and S22-55.
Upsize the existing 10- to 12-inch line between S10-77 and S22-55 to a 15-inch line, install a new 15-inch diversion line between S22-55 and S22-46, and upsize the existing 18-inch line between S22-46 and S22-51 to a 21-inch line.
1. Refer to Figure 4-3 for deficiency locations
2. Under PWWF conditions.
0 0.5
1 Mile µ Legend
Surcharge due to Backwater
Surcharge due to Throttle
Surcharge Criteria Violation
under Existing PWWF
Surcharge Criteria Violation
under Future PWWF
Õ Deficiency ID ÉP Modeled Pump/Lift Station
Modeled Trunk Sewers
Unmodeled Sewers
San Jose Interceptors
City Limit
J:\Projects\149 SANTA CLARA\149-008 Santa Clara 2015 Sanitary Sewer MP Update\G. GIS Files\_MXDs\Master Plan Report Figures\MPFig4-3_Deficiencies_05Apr2016.mxd City of Santa Clara
Sanitary Sewer
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Figure 4-3
Model Predicted
System Surcharge
D1
D1
D2
D4
D3
D7
D5
D6
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Chapter 4
Capacity Analysis
April 2016 4-8
4.3.1 Pump Station Firm Capacity Analysis
All seven lift and pump stations in the system were evaluated to determine if each station had adequate firm capacity to handle the design peak flow. Firm capacity is defined as the capacity of a station with the largest pump out of service. Table 4-3 below provides a summary of station firm capacity compared with peak inflow for future PWWF conditions.
Table 4-3: Pump Station Firm Capacity Analysis
No. Station Name No. of
Pumps
Estimated
Peak Inflow
(mgd) (1)
Estimated
Firm
Capacity
(mgd)
Firm Capacity Status(6)
1 Westside Lift Station 2 0.6 0.6 (3) Sufficient firm capacity 2 Tasman Lift Station 2 1.5 1.5 (3) Sufficient firm capacity 3 De La Cruz Lift Station 2 1.2 1.7 (3) Sufficient firm capacity 4 Primavera Lift Station 6 2.0 5.7 (3) Sufficient firm capacity 5 Stadium Lift Station 6 1.0 6.0 (4) Sufficient firm capacity 6 Rabello Pump Station 8 20 (2) 20 (5) Sufficient firm capacity 7 Northside Pump Station 4 21 (2) 21 (5) Sufficient firm capacity
1. Peak inflow refers to the maximum flows predicted by the model under future peak wet weather scenario using the solution network. The solution network eliminates flow restrictions upstream of the pump stations.
2. Peak inflow reflects the maximum flows predicted by the solution network in which CIP Project P6 (Sewer Diversion at Calabazas Boulevard and Machado Avenue) is implemented, which would divert excess flow from the 24-inch sewer line along Calabazas Boulevard into the 21-inch sewer line in Machado Ave, ultimately flowing to the City of San Jose’s interceptor in Zanker Road. This would reduce the flow conveyed north to the Rabello and Northside Pump Stations to the values shown in the table. Conversely, implementation of Project P6-Alt. would increase the peak flow to the Rabello and Northside Pump Stations by about 1 mgd to each pump station, which could require further evaluation of and potential improvements to increase pump station capacity.
3. Source: Table 1 (Pump Station Firm Capacities and Inflows) of the City of Santa Clara Sanitary Sewer Pump Station Evaluation, Schaaf & Wheeler, December 2010. The firm capacities of Primavera, Tasman, Westside, and De La Cruz lift stations were determined by performing a drawdown test.
4. Based on results from field drawdown tests conducted on September 17, 2015.
5. Source: Rabello and Northside Pump Station Capacity and Forcemain Calibration Technical Memorandum, Schaaf & Wheeler, November 13, 2015. See Appendix E.
6. The lift and pump stations have sufficient firm capacities within the accuracy of the estimated peak flows and capacities.
Although no capacity issues were identified for the pump stations, review of pump station drawings and current on/off set points for the pumps revealed that four of the stations may experience backwater issues in the influent pipes. The current set point of the lead pump at Tasman, Westside, and De La Cruz is above the crown of the influent gravity line. Under this condition, the lead pump will not turn on until the influent line is completely submerged, causing backwater issues upstream. This can be resolved by adjusting the set points to be equal or lower than the invert of the influent line. Primavera Lift Station has a similar condition with the set point of the lag pump. Table 4-4 summarizes the review findings and presents the suggested set points for each of the four stations. Set point revisions for Westside and Tasman are needed to address capacity criteria violations (Deficiencies 1 and 2 in Table 4-2). These settings should be evaluated by the City's pump operators to determine feasibility and if there are other operational issues that should be considered.
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Table 4-4: Recommended Revised Set Levels for Lift Stations Pump Station
Maximum
Starts Per Hour
Per Pump w/
Existing Set
Levels (1)
Maximum
Starts Per Hour
Per Pump w/
Recommended
Set Levels (1)
Set points
Recommended
Revised Set
Points (ft from
Wet Well Floor) (2)
Westside Lift Station
No. of Pumps: 2 7.2 3.7
Level Alarm: High | Low 8.0 | 1.2
Lead Pump on | off 6.0 | 1.7
Lag Pump on | off 7.0 | 2.2
Tasman Lift Station
No. of Pumps: 2 4.6 6.4
Level Alarm: High | Low 7.0 | 1.2
Lead Pump on | off 6.0 | 1.7
Lag Pump on | off 6.5 | 2.2
De La Cruz Lift Station
No. of Pumps: 2 4.8 6.2
Level Alarm: High | Low 6.0 | 1.2
Lead Pump on | off 5.5 | 1.7
Lag Pump on | off 6.0 | 2.2
Primavera Lift Station
No. of Pumps: 6 1.0 2.0
Level Alarm: High | Low 6.0 | 1.2
Lead Pump on | off 5.5 | 1.7
Lag Pump 1 on | off 6.0 | 2.2
Lag Pump 2 on | off 6.0 | 1.2
Lag Pump 3 on | off 5.5 | 1.7
Lag Pump 4 on | off 6.0 | 2.2
Lag Pump 5 on | off 6.0 | 1.2
1. Based on predicted future peak wet weather flow condition.
2. Recommendations provided by Schaaf & Wheeler based on pump information provided by RMC.
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Chapter 5
Recommended Capacity
Improvement Program
April 2016 5-10
Chapter 5 Recommended Capacity Improvement Program
This section summarizes the capacity improvement projects recommended for the City of Santa Clara’s sanitary sewer system. Recommended improvements were developed from the results of hydraulic modeling of the trunk sewer system for predicted flow conditions, as described in Chapter 4. This section discusses the projects needed to address potential capacity deficiencies and unnecessary backups in the existing trunk sewer system including estimated capital costs and priorities for construction.
5.1 Development of Capacity Improvement Projects
Based on the proposed solutions described above, each proposed project was reviewed to identify potential design, permitting, environmental, and constructability issues. Feasible construction methods were also identified for each project, and preliminary estimates of probable construction costs were prepared.
Estimated costs for capacity improvements were based on cost data compiled by RMC from similar projects. The costs are conceptual level estimates, considered to have an estimated accuracy range of -30 to +50 percent, suitable for use for budget forecasting, capital improvement program development, and project evaluations, with the understanding that refinements to the project details and costs would be necessary as projects proceed to design and construction. All costs are presented in 2015 dollars and include a 30 percent allowance for contingencies for unknown conditions and a 25 percent allowance for engineering, administration, and legal costs.
Figure 5-1 shows the locations of the proposed improvements, and Table 5-1 presents the recommended capacity improvement projects, including brief project descriptions and estimated capital costs. Relative priorities have been assigned to the projects based on the flow scenario in which deficiency criteria are violated. Priority 1 and Priority 2 projects are required to address deficiencies that result in criteria violations under current flow conditions. Priority 3 projects are required to address deficiencies that result in criteria violations under future (2035) flow conditions.
Note that an alternative for Project P6 is also presented. While substantially more expensive than Project P6, this alternative would maintain the current system flow configuration of conveying all flows in the Calabazas Creek trunk sewer (including flows from CuSD) to the Northside and Rabello Pump Stations and avoid increasing flows in the Machado, Chromite, and Walsh Avenue trunk sewers that may be needed in the future to handle additional new development within the City. Implementation of Project P6-Alt would also increase flow to the Rabello and Northside Pump Stations by about 1 mgd to each pump station, which could require further evaluation of and potential improvements to increase pump station capacity.
The total estimated cost of the recommended capacity improvement program is approximately $1.7 million.
The total estimated cost, if the City were to implement Project P6-Alt instead of P6, would be approximately $2.8 million. More detailed project descriptions and cost estimates and maps of the recommended capacity improvement projects are included in Appendix F.
One of the projects was triggered due to the large sewer discharge assumed for parcel APN 316-17-018, which holds an entitlement agreement to discharge a potential flow of 0.95 mgd; however, it is currently discharging less than 10 percent of the entitled rate. While the City is obligated to provide capacity for entitlement holders, it is important to note that implementing this project may result in oversized sewers where the daily flow is not sufficient to provide the minimum cleaning velocity and thus creating potential debris and odor issues. This project is included in the summary table as project E1 (Tracy Drive Sewer Improvement), and is not part of the recommended Capital Improvement Program. It is recommended that the City implement project E1 as part of its Capital Improvement Program before the parcel begins to discharge its entitled flow of 0.95 mgd.
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Table 5-1: Recommended Capacity Improvement Projects
Project
ID Priority Project Name U/S MHID D/S MHID Description Est. Capital Improvement Cost1 P12 1 Westside Lift Station Adjustment N/A N/A Adjust the set points for the pumps to a lower elevation to eliminate unnecessary backups in the influent line. -- P22 2 Tasman Lift Station Adjustment N/A N/A Adjust the set points for the pumps to a lower elevation to eliminate unnecessary backups in the influent line. -- P3 2 Cabrillo Avenue Sewer Improvement S41-13 S41-20 Upsize 1,600 feet of 8-inch line in Cabrillo Ave. between Lawrence Expressway and Nobili Ave. to a 12-inch line. $1,097,000 P4 3 Tasman Drive Sewer Improvement S93-24 S93-35 Upsize 600 feet of 12-inch line in Tasman Dr. between Old Ironsides Dr. and Great America Pkwy. to a 15-inch line. $327,000 P5 4 Sewer Diversion at Los Prades Boulevard and Saratoga Avenue S25-85 S25-85
Install a weir in manhole S25-85 located in the intersection of Padres Blvd. and Saratoga Ave. to divert flow northwest to the existing 12-in line in Los Padres Blvd. $77,000
P6 4
Sewer Diversion at Calabazas Boulevard and Machado Avenue U/S of
S52-93 S52-120
Install a new manhole upstream of S52-93 in the intersection of Calabazas Blvd. and Machado Ave., and install a new 15-inch high-level diversion line (approximately 200 feet) to divert excess flow from the existing 24-inch line in Calabazas Blvd. to the 21-inch line in Machado Ave. The diversion line should be about 6 inches higher than the invert of the 24-inch line. $166,000
P6-Alt.3 4 Calabazas Creek Sewer Improvement S62-31 S72-20 Upsize 1,800 feet of 24-inch line next to Calabazas Creek between Kifer Rd. and Scott Blvd. to a 27-inch line. $1,334,000 Estimated Total Cost for Recommended Projects P1 to P6:
Estimated Total Cost for Projects P1 to P5 and P6-Alt:
$1,667,000 $2,835,000
E14 N/A Tracy Drive Sewer Improvement S10-77 S22-51
Upsize approximately 6,600 feet of 10- to 12-inch line in Tracy Dr. and Pomeroy Ave. to a 15-inch line; install a new 15-inch line between manholes S22-55 and S22-46 in Pomeroy Ave. and Homestead Rd. (approximately 50 feet) to divert flow into Homestead Rd., and upsize approximately 1,400 feet of 18-inch line downstream to a 21-inch. $4,654,000
Estimated Total Cost (P1 to P6) including Project E1:
Estimated Total Cost (P1 to P5 and P6-Alt) including Project E1:
$6,321,000 $7,489,000
1. All costs are presented in 2015 dollars and include 30 percent allowance for contingencies for unknown conditions and 25 percent for engineering, administration, and legal costs. 2. These proposed projects are operational, not capital improvements. Refer to Table 4-4 for recommended set points. 3. Project P6-Alt is presented for the purpose of identifying the solution and associated cost to maintain the current system flow configuration. Project P6 is the recommended project. 4. Project E1 addresses the potential capacity deficiency when parcel APN 316-17-018 begins to discharge its entitled flow of 0.95 mgd into the City’s system. 0 0.5 1 Mile
µ Legend
Modeled Trunk Sewer
Unmodeled Sewer
Santa Clara Force Mains
San Jose Interceptors
Recommended Capital Improvement Projects
Project for Entitlement Compliance
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Figure 5-1
Capacity Improvement
Projects and Project for
Entitlement Compliance
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Recommended Capacity
Improvement Program
April 2016 5-13
5.2 Implementation Recommendations
The City should begin implementation of the Capital Improvement Program recommended in this Master Plan, starting with the highest priority projects. The following items should be considered in project scheduling and design, and in future updates of the Master Plan. ▪ The alignments and sizes of all recommended projects should be verified with detailed predesign analyses, including topographic surveys, geotechnical investigations, utility research, and constructability reviews.
▪ The estimated costs assumed open cut construction, but alternative methods such as trenchless construction or construction of parallel relief pipes could be considered during design. The decision to parallel or replace existing sewers should consider the physical condition and remaining useful life of the existing pipelines; the availability of pipeline corridors for new sewer construction; and operation and maintenance concerns.
▪ The hydraulic model has been developed to assist the City in performing capacity analyses and updating the Master Plan in the future. The model should be kept up-to-date with any changes to existing sewer connections, development plans, and sewer system facilities. ▪ The City should conduct additional flow monitoring at key locations in the sewer system, particularly the area tributary to the Chromite/Machado trunk sewers where both the 2006 and 2015 flow monitoring programs indicated high I/I. City should also conduct smoke testing and television inspection to identify potential sources of I/I. Flow levels during large storm events should be compared to the peak flows simulated by the hydraulic model to verify the modeling predictions for the 10-year design storm and confirm the need for and sizing of Project P3 (Cabrillo Avenue Sewer Improvement). ▪ The City should coordinate with the CuSD on flow and planning assumptions to ensure that adequate capacity exists in the Santa Clara system to handle future flows from the District. The City should encourage CuSD to monitor the flows at the flow meter that it operates and maintains on Homestead Road at Swallow Drive on an on-going basis and periodically confirm meter calibration to verify the wastewater flows entering the Santa Clara system.
▪ The City should consider adjusting its set points for the four lift stations identified in Table 4-4 to address upstream backwater issues and capacity criteria violations. These settings should be evaluated by the City's pump operators to determine feasibility and if there are other operational issues that should be considered. In addition, the City should continue to conduct regular maintenance as needed to maintain adequate firm pumping capacity at all pump stations, including cleaning the force mains as needed.
▪ The City should coordinate with the City of San Jose to ensure that its flow criteria and planning assumptions are consistent with those used by San Jose in its capacity master planning. ▪ Parcel APN 316-17-018 holds an entitlement agreement to discharge up to 0.95 mgd into the City’s system; however, it is currently discharging less than 10 percent of its entitled rate. While the City is obligated to provide capacity for entitlement holders, it is important to note that implementing this project may result in oversized sewers where the daily flow is not sufficient to provide the minimum cleaning velocity and thus creating potential debris and odor issues. However, the City should implement project E1 (Tracy Drive Sewer Improvement) to address the potential capacity deficiency before the parcel begins to discharge its entitled flow of 0.95 mgd.
City of Santa Clara
Sanitary Sewer Master Plan Update
Chapter 5
Recommended Capacity
Improvement Program
April 2016 5-14
This Master Plan report is intended to be a working document to be refined and updated as additional data and new planning information becomes available. The capacity assessment should be updated whenever there are major changes in planning assumptions or, at a minimum, every ten years.
Sanitary Sewer
Master Plan
Update
Draft Report
0012307.00
City of Santa Clara
December 2024
woodardcurran.com
51 East Campbell Avenue | Suite 128
Campbell, California 95008
800.426.4262
City of Santa Clara (0012307.00) TOC-1 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
TABLE OF CONTENTS
SECTION PAGE NO.
EXECUTIVE SUMMARY...........................................................................................................................ES-1
1. INTRODUCTION..............................................................................................................................1-1
1.1 Background and Study Objectives ...........................................................................................................1-1
1.2 Sanitary Sewer System and Service Area...............................................................................................1-1
1.3 Report Organization ......................................................................................................................................1-4
2. WASTEWATER FLOW ASSUMPTIONS...........................................................................................2-1
2.1 Flow Monitoring Program ...........................................................................................................................2-1
2.1.1 Flow Monitoring and Rain Gauge Sites .....................................................................................2-1
2.1.2 Flow Monitoring Data.......................................................................................................................2-6
2.1.3 Additional Monitoring for Dry Weather Flow Verification .................................................2-7
2.2 Basis of Hydraulic Model’s Wastewater Flow Estimates ..................................................................2-7
2.2.1 Wastewater Flow Components .....................................................................................................2-7
2.2.2 Base Wastewater Flow Estimates..................................................................................................2-8
2.2.2.1 Existing BWF Loads ............................................................................................................2-9
2.2.2.2 Future BWF Loads............................................................................................................ 2-12
2.2.3 Groundwater Infiltration ............................................................................................................... 2-15
2.3 Rainfall-Dependent I/I................................................................................................................................ 2-16
3. HYDRAULIC MODEL DEVELOPMENT AND VALIDATION ............................................................3-1
3.1 Hydraulic Modeling Software and Modeling Terminology............................................................3-1
3.2 Hydraulic Model Network Development...............................................................................................3-2
3.2.1 Modeled System .................................................................................................................................3-2
3.2.2 Model Network Construction and Validation .........................................................................3-3
3.2.3 Subcatchments ....................................................................................................................................3-4
3.2.4 Special Structures and Flow Splits ...............................................................................................3-5
3.2.5 Pump Stations ......................................................................................................................................3-5
3.2.5.1 Siphons ...................................................................................................................................3-6
3.2.5.2 Flow Splits..............................................................................................................................3-7
3.3 Model Calibration Process and Results ..................................................................................................3-7
3.4 Dry Weather Flow Calibration....................................................................................................................3-7
3.4.1 Dry Weather Flow Calibration Methodology...........................................................................3-8
3.4.1.1 Review of Largest Water Users ......................................................................................3-8
3.4.1.2 Diurnal Pattern Development and Refinement.................................................... 3-12
3.4.2 Base Flow Adjustments and Addition of GWI ...................................................................... 3-13
3.4.3 Dry Weather Flow Calibration Results ..................................................................................... 3-14
3.4.3.1 Differences Between 2022-2023 & 2014-2015 Flow Monitoring Data ...... 3-19
3.5 Wet Weather Flow Calibration................................................................................................................ 3-21
3.5.1 Wet Weather Flow Calibration Methodology ...................................................................... 3-21
3.5.2 Wet Weather Flow Calibration Results.................................................................................... 3-21
3.5.2.1 RDI/I Response.................................................................................................................. 3-26
4. SYSTEM CAPACITY ANALYSIS .......................................................................................................4-1 City of Santa Clara (0012307.00) TOC-2 Woodard & Curran, Inc.
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4.1 Hydraulic Assumptions Used for the Capacity Analysis ..................................................................4-1
4.1.1 Summary of Design Storm, Performance Criteria, and Design Criteria ........................4-1
4.1.2 Physical Model Network ..................................................................................................................4-9
4.1.2.1 Lined Model Network Assumptions......................................................................... 4-10
4.2 Capacity Evaluation Results ..................................................................................................................... 4-13
4.3 Gravity Sewer System Capacity Deficiencies ..................................................................................... 4-13
4.4 Pump Station and Force Main Capacity Deficiencies .................................................................... 4-16
4.5 Capacity Improvement Projects ............................................................................................................. 4-17
4.5.1 Agilent.................................................................................................................................................. 4-21
4.5.2 Homestead Road ............................................................................................................................. 4-21
4.5.3 Kiely Boulevard ................................................................................................................................. 4-22
4.5.4 Victoria Avenue ................................................................................................................................ 4-22
4.5.5 Cabrillo Avenue ................................................................................................................................ 4-23
4.5.6 CMC Basin........................................................................................................................................... 4-23
4.5.7 Bowers Avenue ................................................................................................................................. 4-24
4.5.8 Calabazas Trunk ............................................................................................................................... 4-24
4.5.9 Freedom Circle.................................................................................................................................. 4-24
4.5.10 GAP West Trunk ............................................................................................................................... 4-25
4.5.11 GAP East Trunk ................................................................................................................................. 4-25
4.5.12 Bunker Hill Lane East...................................................................................................................... 4-26
4.5.13 Lafayette Street................................................................................................................................. 4-26
4.6 Infiltration and Inflow Discussion .......................................................................................................... 4-26
4.6.1 Completed Infiltration and Inflow Investigations ............................................................... 4-27
4.6.2 I/I Source Detection and Control Methods ........................................................................... 4-29
4.6.3 I/I Investigation Recommendations for Santa Clara .......................................................... 4-30
5. RECOMMENDED SEWER CAPACITY CAPITAL IMPROVEMENT PROGRAM ...............................5-1
5.1 Project Development Process ....................................................................................................................5-1
5.2 Project Prioritization Methodology..........................................................................................................5-1
5.3 Project Level of Confidence ........................................................................................................................5-2
5.4 Project Cost Estimates...................................................................................................................................5-3
5.5 Other Costs........................................................................................................................................................5-3
5.6 Project Costs Financed by Developers ...................................................................................................5-4
5.7 Summary of Recommended Capacity Improvement Projects ......................................................5-4
5.7.1 Agilent.....................................................................................................................................................5-7
5.7.2 Homestead Road ................................................................................................................................5-7
5.7.3 Kiely Boulevard ....................................................................................................................................5-7
5.7.4 Victoria Avenue ...................................................................................................................................5-7
5.7.5 Cabrillo Avenue ...................................................................................................................................5-8
5.7.6 CMC Basin..............................................................................................................................................5-8
5.7.7 Bowers Avenue ....................................................................................................................................5-8
5.7.8 Calabazas Trunk ..................................................................................................................................5-9
5.7.9 Freedom Circle.....................................................................................................................................5-9
5.7.10 GAP West Trunk ..................................................................................................................................5-9
5.7.11 GAP East Trunk ................................................................................................................................. 5-10
5.7.12 Bunker Hill East Lane...................................................................................................................... 5-10
5.7.13 Lafayette Street................................................................................................................................. 5-10 City of Santa Clara (0012307.00) TOC-3 Woodard & Curran, Inc.
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5.8 Schedule .......................................................................................................................................................... 5-10
5.9 Implementation Recommendations ..................................................................................................... 5-11 TABLES
Table ES-1: Summary of Sanitary Sewer System Infrastructure Table ES-2: Average Base Wastewater Flow Assumptions for Santa Clara1 Table ES-3: Wastewater Flow Assumptions for CuSD1
Table ES-4: Summary of Hydraulic Model Calibration Results1 Table ES-5: Summary of Design and Performance Criteria
Table ES-6: Summary of Capacity Analysis Model Scenarios Table ES-7: Summary of Recommended Sewer Capacity CIP
Table ES-8: Capacity Improvement Project Details
Table 1-1: Summary of Sanitary Sewer System Infrastructure Table 2-1: Flow Meter Sites
Table 2-2: Summary of BWF Loads for Existing, Near-Term, and Future Conditions1 Table 2-3: Land Use Classifications and Existing BWFs by Use Category Table 2-4: Unit Flow Factors Used to Estimate Future BWF Loads Table 2-5: Wastewater Flow Assumptions for CuSD1
Table 3-1: Sewer System Model Pipe Summary
Table 3-2: Sewer System Model Pump Station Summary
Table 3-3: City’s Largest Water Users (water use greater than 50,000 gpd) Table 3-4: Dry Weather Flow Calibration Results Summary1 Table 3-5: Dry Weather Flow Calibration Results vs. 2022-2023 Flow Monitoring Data1 Table 3-6: Dry Weather Flow Calibration Results vs. Select 2014-2015 Flow Monitoring Data1 Table 3-7: Dry Weather Flow Summary (Existing Conditions) Table 3-8: Rainfall Events Referenced for Wet Weather Calibration1 Table 3-9: Wet Weather Flow Calibration Results Summary1 Table 3-10: Wet Weather Flow Calibration Results vs. 2022-2023 Flow Monitoring Data1 Table 3-11: Wet Weather Flow Calibration Results vs. Select 2014-2015 Flow Monitoring Data1 Table 4-1: Rainfall Design Event Criteria Used for Santa Clara Master Plan Update Table 4-2: Characteristics of Design Storm Distributions Considered1 Table 4-3: Capacity Deficiency Criteria Used for Santa Clara Master Plan Update Table 4-4: Design Criteria Used for Santa Clara Master Plan Update Table 4-5: Future Liner Thickness Assumptions for RCP Trunks and Siphons (Lined Model Network Only)1 Table 4-6: RCP Trunks Identified for Future Lining (Lined Model Network Only) Table 4-7: Summary of Model-Predicted Gravity Sewer Capacity Deficiencies Table 4-8: Summary of Model-Predicted Pump Station and Force Main Capacity Deficiencies Table 4-9: Summary of Capacity Improvement Projects
Table 5-1: Project Prioritization Ranking1
Table 5-2: Project Flow Confirmation Levels
Table 5-3: Other Costs in Addition to Sewer Capacity CIP Project costs Table 5-4: Capacity Improvement Projects
Table 5-5: Capacity Improvement Projects Schedule
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FIGURES
Figure ES-1: Santa Clara Sanitary Sewer System and Service Area Figure ES-2: Flow Monitoring Program
Figure ES-3: RDI/I Rate by Flow Meter Basin
Figure ES-4: Overview of Capacity Deficiencies
Figure ES-5: Overview of Capacity Improvement Projects
Figure 1-1: Santa Clara Sanitary Sewer System and Service Area Figure 2-1: Flow Monitoring Program
Figure 2-2: Trunk Sewer System Schematic
Figure 2-3: Plot of Typical Flow Data for 2022-2023 Flow Monitoring Period Figure 2-4: Wastewater Flow Components
Figure 2-5: Water Billing Data
Figure 2-6: RDI/I Hydrograph Components
Figure 3-1: Sample Siphon Profile
Figure 3-2: Flume Diversion Structure to Homestead Rd. or Lawrence Expwy.
Figure 3-3: City’s Top Water Users (water use greater than 50,000 gpd) Figure 3-4: Residential Diurnal Patterns
Figure 3-5: Non-Residential Diurnal Profiles
Figure 3-6: Dry Weather Calibration Graph (FM 1)
Figure 3-7: Dry Weather Calibration Graph (FM 2)
Figure 3-8: Dry Weather Calibration Graph (FM 3)
Figure 3-9: Daily Rainfall Observed During 2022-2023 Flow Monitoring Period (in)1 Figure 3-10: Wet Weather Calibration Results at FM 1
Figure 3-11: Wet Weather Calibration Results at FM 2
Figure 3-12: Wet Weather Calibration Results at FM 3
Figure 3-13: Wet Weather Calibration Results – RDI/I Response at FM 31 Figure 3-14: Wet Weather Calibration Results – RDI/I Response at FM 27 Figure 3-15: Wet Weather Calibration Results – RDI/I Rates by Flow Meter Basin Figure 4-1: Design Storm Event for Central Santa Clara (MAP ~14.5 inches) Figure 4-2: Design Storm Event for Central Santa Clara (Weekend) Figure 4-3: Design Storm Event for Central Santa Clara (Weekday) Figure 4-4: Spatial Variation of Rainfall Throughout Santa Clara’s Service Area Figure 4-5: RCP Trunks Identified for Future Lining (Lined Model Network Only) Figure 4-6: Capacity Deficiencies Overview Map
Figure 4-7: Capacity Improvement Projects Overview Map
Figure 4-8: CMC Basin Tributary Area
Figure 4-9: Observed flow monitoring data at FM 31 (S62-50, 10”) Figure 4-10: NOAA Rainfall Statistics Compared to Observed January 2023 Rainfall in Santa Clara, CA
APPENDICES
Appendix A: Flow Monitoring Data Plots
Appendix B: Future Development Assumptions
Appendix C: Pump Station Capacity Calculations
Appendix D: Field-Collected Survey Information Data Sheets City of Santa Clara (0012307.00) TOC-5 Woodard & Curran, Inc.
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Appendix E: Calibration Results
Appendix F: Siphon Lining Assumptions
Appendix G: Sewer Capacity CIP Project Cost Estimates, Maps, and Profiles
ACKNOWLEDGEMENTS
City of Santa Clara
Craig Temple, Principal Engineer (Project Manager)
Falguni Amin, Principal Engineer
Woodard & Curran
Kraig Erickson, Project Manager
Nuria Bertran-Ortiz, Technical Manager
Stephanie Estabrook, Project Engineer
Nery Barrera, Staff Engineer
Cathy Greenman, Technical Reviewer
Gisa Ju, Technical Reviewer
Subconsultants
V&A Consulting Engineers, Inc. (Flow Monitoring)
LIST OF ACRONYMS AND ABBREVIATIONS
ADWF Average Dry Weather Flow
APN Assessor Parcel Number
BWF Base Wastewater Flow
CCTV Closed-Circuit Television
CIP Capital Improvement Program or Capital Improvement Plan CIPP Cured-in-Place Pipe
City City of Santa Clara
CMC Chromite-Machado-Cabrillo
County Santa Clara County
CSJ City of San Jose
CuSD Cupertino Sanitary District
d/D Depth to Diameter Ratio
DDF Depth, Duration, Frequency
DIP Ductile Iron Pipe
DTM Digital Terrain Model
DU Dwelling Unit
DWF Dry Weather Flow
EL Existing Loads
ENR CCI Engineering News Record Construction Cost Index FAR Floor-area-ratio
FM Flow Meter
fps Feet per second
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GAP Great America Parkway
GIS Geographic Information System
GP General Plan
gpd Gallons per day
gpcd Gallons per capita per day
GWI Groundwater Infiltration
I/I Infiltration and Inflow
ICM InfoWorks ICM™
IDF Intensity, Duration, Frequency
LiDAR Light Detection and Ranging
LF Linear Feet
LMN Lined Model Network (Future)
LTFL Long-Term Future Loads
MAP Mean Annual Precipitation
mgd Million gallons per day
MH Sanitary Sewer Manhole
MP Master Plan
NAICS North American Industry Classification System
NAVD North American Vertical Datum of 1988
NGVD National Geodetic Vertical Datum of 1929
NOAA National Oceanic and Atmospheric Administration
NRCS Natural Resources Conservation Service
NTFL Near-Term Future Loads
PDWF Peak Dry Weather Flow
PHD Patrick Henry Drive
PS Pump Station
PVC Polyvinyl Chloride (Pipe)
PWWF Peak Wet Weather Flow
RCP Reinforced Concrete Pipe
RDI/I Rainfall-Dependent Infiltration and Inflow
SCADA Supervisory Control and Data Acquisition
SCS Soil Conservation Service
SD Specific Development
SF Square Feet
SJ/SC RWF San Jose / Santa Clara Regional Wastewater Facility SMH Sanitary Sewer Manhole
SSO Sanitary Sewer Overflow
UMN Unlined Model Network (Current)
USDA United States Department of Agriculture
V&A V&A Consulting Engineers, Inc.
VCP Vitrified Clay Pipe
VFD Variable Frequency Drive
W&C Woodard & Curran
WWF Wet Weather Flow
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EXECUTIVE SUMMARY
This report summarizes the results and recommendations of the Sanitary Sewer Master Plan Update (Master Plan Update) for the City of Santa Clara (City or Santa Clara). Woodard & Curran prepared the Master Plan Update in close coordination with City staff. The Master Plan Update will be used to guide improvements to the City’s sewer system to accommodate current and future development and to help the City continue to provide a high level of service to its customers.
The overall objectives of this Master Plan Update were to develop wastewater flow projections for the City’s sewer service area using up-to-date development and land use information and flow monitoring data; update and expand its existing hydraulic model of the sanitary sewer system; use the model to identify existing capacity deficiencies and future capacity requirements; and develop a phased Capital Improvement Program (CIP), including cost estimates, for implementing the required capacity improvements to the sewer system.
The Master Plan Update included preparation of the following four (4) key technical memoranda (TMs), which were referenced for development of this Master Plan Update report:
• TM #1 – Santa Clara Sewer Model Development and Calibration • TM #2 – Santa Clara Sewer Performance and Design Criteria • TM #3 – Santa Clara Sewer Performance Evaluation
• TM #4 – Capital Improvement Plan Report
This Executive Summary provides a concise summary of the Master Plan Update report, highlighting critical information including objectives, findings, conclusions, and recommendations. It is presented in three parts:
1) Introduction to the City’s Existing Sewer System and Service Area (Section ES-1) discusses the City of Santa Clara’s existing sewer system infrastructure and service area. 2) Description of How the Capacity Analysis was Prepared (Section 0) describes the scope and methodologies of the planning effort, including the key planning and technical assumptions incorporated into the sewer system capacity analysis.
3) Recommended Capital Improvement Program (Section ES-3) presents the recommended CIP, including capacity improvement projects, phasing, and estimated costs. In addition, recommendations are presented for implementing the proposed CIP.
ES-1 Introduction to the City’s Existing Sewer System and Service Area Santa Clara is located in central Santa Clara County adjacent to the cities of San Jose, Cupertino, and Sunnyvale and covers approximately 18 square miles. The City has a population of approximately 130,000 and is served by a wastewater system comprising approximately 288 miles of sewer pipelines generally ranging from 4 to 48 inches in diameter (including 12 miles of private sewer pipelines) and seven (7) sewage pump stations.
The City collects wastewater generated within the City’s service area from approximately 25,000 City customers (connections). Based on the City’s billing database, roughly 90% of the City’s existing customers are residential users and the remaining 10% are non-residential users, including commercial, municipal, and industrial users. In addition to collecting wastewater flows from customers within its service area, the City City of Santa Clara (0012307.00) ES-2 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
also has an agreement to convey wastewater flows from a major portion of the Cupertino Sanitary District (CuSD) via a connection at Homestead Road and Swallow Drive.
Wastewater flows collected are generally conveyed eastward and northward. A portion of the City’s flow continues eastward to the Trimble Trunk and conveyed to the City of San Jose’s interceptor sewers on Zanker Road. The remainder of the City’s flow and all the CuSD flow travels northward to the City’s Northside and Rabello Pump Stations, where the flow is pumped to the San Jose/Santa Clara Regional Wastewater Facility (SJ/SC RWF) for treatment and disposal. The City’s sewer system and service area are shown in Figure ES-1. A summary of the City’s sanitary sewer system infrastructure is presented in Table ES-1.
TABLE ES-1: SUMMARY OF SANITARY SEWER SYSTEM INFRASTRUCTURE Infrastructure Quantity Unit
Sewer Mains (Pipes) 1,456,4001/ 276 Feet / Miles
Manholes 5,500 -
Siphons 34 (59 barrels2) -
Pump Stations 7 -
1Total length is rounded to the nearest one hundred feet. 2Some siphons have multiple barrels: Three (3) siphons have three (3) barrels, 19 siphons have two (2) barrels, and the remaining 12 siphons have a single barrel.
De La Cruz LS
Primavera LS
Westside LS
Rabello PS
Northside PS
Tasman LS
Stadium LS
SC Influent
Junction
Structure
CuSD Flow
Legend
Figure ES-1
Sanitary Sewer System
and Service Area
Sewer Master Plan Update
Figure Exported: 12/27/2024 By: SEstabrook Using: \\woodardcurran.net\shared\Projects\0012307.00 Santa Clara CA Sewer Master Plan Update\wip\C. GIS\3. ArcGIS Pro\SantaClaraSewerMasterPlan2024_Report.aprx City Boundary
Pump Station
Santa Clara Force Mains
San Jose Interceptors
CuSD Joint Usage Sewers
Sewers by Diameter
≤6"
8"-10"
>10"-16"
>16"-24"
≥27"
CSJ Interceptor
(Not Modeled)
San Jose/Santa Clara
Regional
Wastewater Facility
Project #: 0012307.00
Map Created: December 2024
Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions.
Any reliance upon the map or data contained herein shall be at the users’ sole risk. ±
0 0.25 0.5 1
Miles
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ES-2 Description of How the Capacity Analysis was Prepared This study is intended to provide a comprehensive update of the City’s Sanitary Sewer Master Plan to reflect the most current and accurate information on wastewater flows, projected growth, and system performance.
To accomplish this, the City recognizes the need to update the hydraulic model of its sewer system, which is used to assess system performance and identify system capacity needs for both existing and projected future wastewater flows. This section describes how the capacity analysis was prepared and discusses the wastewater flow assumptions, hydraulic model development and calibration, design and performance criteria, and capacity analysis scenarios and results.
Wastewater Flow Assumptions
Wastewater flow assumptions are required to develop a hydraulic model that is an accurate representation of reality. The Santa Clara model includes both existing and future projected wastewater flow scenarios.
Existing base wastewater flow (BWF) was estimated for each parcel within the City’s service area based on recent customer water usage records obtained from the City’s water billing database.
Future BWF projections were estimated by incorporating the most current development information that was available for the City’s service area, which included development projects in review, specific plans, General Plan, and entitlement agreements. Based on the timing and type of development, the future base wastewater flows were assigned to one of two scenarios: near-term future or long-term future. The longterm future scenario included all development assumptions applied to the near-term future scenario plus development assumptions associated with the City’s General Plan and entitlement agreements. The City’s billing database records show that many entitlement holders have historically discharged less than their flow entitlements; however, considering the City is required to provide capacity to these users should they have the need to increase their discharges, the long-term future BWF scenario conservatively assumes that all entitlement holders would make use of their full discharge allowances.
Table ES-2 summarizes the average BWF assumptions applied to the hydraulic model for the City’s service area.
TABLE ES-2: AVERAGE BASE WASTEWATER FLOW ASSUMPTIONS FOR SANTA CLARA1 Land Use Residential Non-Residential Total
Flow Scenario (mgd) (mgd) (mgd)
Existing 6.72 4.50 11.22
Near-Term Future 10.11 6.09 16.20
Long-Term Future2 13.58 15.48 29.06
1Does not include sewer flows from the Cupertino Sanitary District (CuSD). Refer to Table ES-3. 2 Includes 5.09 mgd assumed for entitlement agreements, mostly for non-residential land uses.
The Santa Clara hydraulic model includes flow scenarios that represent both dry weather (non-rainfall) and wet weather (rainfall) conditions. In dry weather conditions, the base wastewater flows presented above account for the vast majority of total discharges to the sewer system. During wet weather conditions, total discharges to the sanitary sewer system increase due to the introduction of storm water inflow and infiltration, which enters the sanitary sewer system in direct response to rainfall events through holes in manhole covers, defects in sewer pipelines and service laterals, or illegally connected storm drainage infrastructure. If groundwater levels are high enough, some infiltration can also occur during dry weather conditions as it infiltrates into sewer infrastructure from below through defects. Wet weather flows are generated by simulating a design storm rainfall event in the hydraulic model.
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Because CuSD discharges to Santa Clara’s sanitary sewer system, the existing and future projected wastewater flow scenarios in the hydraulic model also include wastewater flow assumptions for CuSD for both dry and wet weather conditions. CuSD flows were incorporated into the hydraulic model as inflow hydrographs, which define the rate of wastewater flow entering a specific point (i.e., manhole) in the network during a simulation. CuSD flows for existing dry weather conditions were based on flow monitoring data.
CuSD flows for existing wet weather conditions, near-term future dry and wet weather conditions, and longterm future dry and wet weather conditions were based on flows from CuSD’s hydraulic model, which was most recently re-calibrated in 2023 by AKEL Engineering. For these flow scenarios, Woodard & Curran created inflow hydrographs based on the results that were exported from CuSD’s re-calibrated model; the magnitude of flows was maintained but the timing was slightly shifted to match the diurnal usage pattern observed in the flow monitoring data and to align the peak wet weather response where applicable. For the long-term future wet weather flow scenario only, the peak flow was conservatively scaled up to match the contractual limit (13.8 mgd) defined in Santa Clara’s agreement with CuSD.
Table ES-3 summarizes CuSD’s average BWF assumptions applied to the hydraulic model for the City’s service area.
TABLE ES-3: WASTEWATER FLOW ASSUMPTIONS FOR CUSD1
Flow Scenario Average Dry Peak Dry Average Wet Peak Wet (mgd) (mgd) (mgd) (mgd)
Existing 3.7 5.6 4.1 10.7
Near-Term Future 4.2 6.3 4.6 11.3
Long-Term Future 4.6 6.7 5.9 13.82
1Based on CuSD’s hydraulic model results for a seven (7) day period. 2Assumed to be contractual limit defined in agreement between Santa Clara and CuSD.
Hydraulic Model Network Development
A hydraulic model of the City’s sewer system was developed for this study. The model includes all Cityowned pipes and manholes within the sanitary sewer system, excluding approximately 12 miles of privatelyowned sewer mains. Therefore, the model network consists of about 276 miles of sewers, including 2.7 miles of force mains, or roughly 96% of the total 288 miles of sewer pipeline within the City’s system. The model also includes all seven sewage pumping stations. The model is a significant expansion of the model used for the 2016 Master Plan, which was developed to represent the trunk or “backbone” of the sewer system and as such contained approximately 34% (or 94 miles) of the total length of the City’s sewers. Since 2016, Woodard & Curran has maintained and updated the City’s model as sewer improvement projects were implemented, development reviews were requested, or when new network data became available, and this Master Plan Update builds on that work by significantly expanding the model network to include all Cityowned sewer pipelines.
The model was used to assess how the system would perform under various planning and flow scenarios and to identify pipes or pump stations that may not have sufficient capacity to convey the predicted flows under existing or future conditions.
Hydraulic Model Calibration
Before the hydraulic model can be used for the capacity analysis performance evaluation, it must be calibrated to confirm that it is an accurate representation of the flows and hydraulic conditions in the City’s sanitary sewer system. Model calibration is the process of comparing model-simulated flows to observed flows and adjusting the model assumptions and parameters as needed until a reasonably good match is City of Santa Clara (0012307.00) ES-6 Woodard & Curran, Inc.
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achieved. Generally, the model calibrator attempts to match flow volumes and peak flows between the model-simulated and observed data.
Model calibration is first performed for dry weather flows to achieve an accurate prediction of the base wastewater flows and baseline groundwater infiltration if present during non-rainfall conditions. Wet weather calibration is then performed to achieve an accurate prediction of the storm water inflow and infiltration that discharges to the sanitary sewer system during rainfall events.
A temporary flow monitoring program (shown in Figure ES-2) was conducted as part of this study to facilitate model calibration. The program obtained flow depth and velocity data (used to compute flow rate) at 31 strategically identified locations throughout Santa Clara’s sanitary sewer system during both dry weather and wet weather conditions and rainfall data at three distinct locations. The observed data were compared to the model-simulated flows during the calibration process to confirm actual flows and system routing and characterize infiltration and inflow into the sewers within each distinct flow meter (FM) basin.
The model calibration process also included reviewing key flow splits in the City’s sewer system to confirm flow routing, refining diurnal flow patterns to accurately represent the typical variation of flows throughout the day, and reviewing the City’s largest dischargers and their discharge locations.
Table ES-4 summarizes the final model calibration results for the overall system based on discharge location by comparing model-simulated to observed flows during both dry weather and wet weather conditions for the downstream most flow meters. It was determined that a reasonably good match was achieved for the overall system considering the observed average dry weather flows and peak wet weather flows were within 10% of the model-simulated flows at both discharge locations. The period used for the dry weather calibration was the seven (7) day dry period from December 17 through December 23, 2022. Wet weather calibration was performed for the full 2022-2023 season because the flow monitoring program captured several rainfall events. The January 13-16, 2023 rainfall event produced the largest flow response and was used as the primary basis for calibrating the model to match observed peak wet weather flows. Several storms occurred within a short amount of time during the flow monitoring period, so there were likely cumulative impacts that increased the inflow and infiltration response during the subsequent storms.
Additionally, the calibration focused on selecting parameters to conservatively match peak flows observed during the mid-January event which occurred later in the season after significant rainfall had already fallen and soils were generally saturated. As a result, the modeled and metered peak flows and volumes typically matched better for the later season rainfall events.
TABLE ES-4: SUMMARY OF HYDRAULIC MODEL CALIBRATION RESULTS1 Average Dry Weather Flows (mgd) Peak Wet Weather Flows (mgd) Discharge Location Observed Modeled Difference2 Observed Modeled Difference2 Santa Clara Northside and
Rabello Pump Stations3
10.54 10.09 -4.3% 23.03 24.22 +5.2%
Trimble Trunk 4.65 4.46 -4.1% 13.65 13.93 +2.1%
1Model results are compared to the 2022-2023 flow monitoring data. 2Difference is reported as modeled minus observed flow. 3 Includes flows from CuSD.
The infiltration and inflow response to rainfall, which is referred to as rainfall-dependent infiltration and inflow (RDI/I), was quantified within each flow meter basin through the wet weather calibration process.
Figure ES-3 presents a visual representation of the wet weather calibration model results in terms of the City of Santa Clara (0012307.00) ES-7 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
total RDI/I rate that was applied to the model for each meter basin to match model-simulated and observed flows. The total RDI/I rate (or “Total R”) is a percentage that represents the total amount of rainfall that becomes runoff and eventually enters the sanitary sewer system as RDI/I. As shown in the figure, half of the City’s flow meter basins had RDI/I rates of less than 5%. In contrast, flow meter basins concentrated within the central western portion of Santa Clara’s system displayed very high RDI/I rates of greater than 80%.
These flow meter basins are located within the Chromite-Machado-Cabrillo (CMC) tributary area and the adjacent Agate Drive tributary area. The flow monitoring data showed that the nature of the RDI/I responses to rainfall in these areas were indicative of significant infiltration, as the response was generally slower and took a long time to recede (i.e., several weeks following rainfall). Moreover, because consecutive rainfall events occurred within a short period of time during the flow monitoring period, the infiltration response did not fully recede before another rainfall event occurred. The flow monitoring results were consistent with the findings of other field investigations completed recently in the CMC basin, which concluded that rainfalldependent infiltration appeared to be the most significant contributor to the wet weather response, possibly from defects in tributary sewer laterals and mains.
During the dry weather calibration process, a total of 0.158 mgd of additional GWI flow was applied to the system uniformly throughout two (2) of the 31 flow meter areas (i.e., FM 26 and FM 31), which were located in the CMC and Agate Drive tributary areas, respectively. GWI represents a seasonal increase in wastewater flows due to infiltration into the sewers during non-rainfall conditions, typically in low-lying areas or areas close to creeks or other water bodies. The need to add GWI to these flow meter basins to calibrate for dry weather conditions further suggests that significant infiltration is occurring, likely through defects in tributary sewer laterals and mains.
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23 2&3
1 5
31 22
13 19&20
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28 21
24 6
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10 25
16 29
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11 17
7 20
27 30
3 FM 1
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FM
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FM 20
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3 FM 30
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FM 5
FM 6
FM
7 FM 8
FM 9A
FM 31
CuSD Meter
De La
Cruz LS
Westside LS Primavera LS
Rabello PS
Northside PS
Tasman LS
Stadium LS
SC Influent
Junction
Structure
Legend
Figure Exported: 12/31/2024 By: SEstabrook Using: \\woodardcurran.net\shared\Projects\0012307.00 Santa Clara CA Sewer Master Plan Update\wip\C. GIS\3. ArcGIS Pro\SantaClaraSewerMasterPlan2024_Report.aprx Project #: 0012307.00
Map Created: December 2024
Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions.
Any reliance upon the map or data contained herein shall be at the users’ sole risk. % 2014-2015 & 2022-2023 Flow Meter Site
% 2022-2023 Flow Meter Site
%, CuSD Flow Meter Site (FM 32)
City of Santa Clara Boundary
Pump Station
San Jose Interceptors
Trunk Mains
Gravity Main
Force Main
Small Diameter Mains
Flow Meter Basin
1 10
11 12
13 14
15 16
17 18
19&20
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20 21
22 23
24 25
26 27
28 29
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31 4
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9A&24
9A&30
9A&31
Figure ES-2
Flow Monitoring
Program
Sewer Master Plan Update
±
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San Jose/Santa Clara
Regional
Wastewater Facility
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Legend
Figure Exported: 12/27/2024 By: SEstabrook Using: \\woodardcurran.net\shared\Projects\0012307.00 Santa Clara CA Sewer Master Plan Update\wip\C. GIS\3. ArcGIS Pro\SantaClaraSewerMasterPlan2024_Report.aprx Project #: 0012307.00
Map Created: December 2024
Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions.
Any reliance upon the map or data contained herein shall be at the users’ sole risk.
City of Santa Clara Boundary
2022-23 Flow Meters
% 2014-2015 & 2022-2023 Flow Meter Site
% 2022-2023 Flow Meter Site
RDI/I Rate (Total R)
0 - < 5
5 - 10
> 10 - 20
> 20 - 40
Figure ES-3 > 80
RDI/I Rate by
Flow Meter Basin
Sewer Master Plan Update
±
0 0.25 0.5 1
Miles
City of Santa Clara (0012307.00) ES-10 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
Design and Performance Criteria
The capacity analysis requires selection of design and performance criteria, which are applied so that the hydraulic model can be used to determine if sewer facilities would have adequate capacity under the flow scenarios developed or if the capacity would be exceeded, requiring system improvements. Table ES-5 presents and describes the design and performance criteria that were selected for this Master Plan Update.
TABLE ES-5: SUMMARY OF DESIGN AND PERFORMANCE CRITERIA
Criterion Purpose Selected
Design
Storm
Rainfall
Single event rainfall
assumed to produce peak
flows generated from a
rainfall event of a desired
return period to assess
system capacity during
wet weather conditions.
• Return Period: 10 years
• Duration: 24 hours
• Rainfall Depth and Temporal Distribution: Based on
Santa Clara County Drainage Manual (developed
from historical rainfall event in December 1955)
• Storm Timing: Peak-on-peak1(weekday)
• Antecedent Conditions: Wet, saturated soils
• Spatial Distribution: Lowest intensity north and
highest intensity southwest
Performance
(Capacity
Deficiency)
Used to determine if the
capacity of an existing
sewer facility is inadequate
to the extent that a
capacity improvement
project would be needed.
• Gravity Sewers: Flow depth exceeds full pipe (d/D2 >
1) during either dry weather or design storm wet
weather conditions (i.e., no surcharge is allowed).
• Pump Stations: Firm capacity3 greater than the peak
wet weather flow during the design storm.
• Force Mains: Velocity exceeds 8 feet per second (fps).
Design
Used for the purpose of
sizing new or relief
facilities based on the
City’s desired level of
service and are generally
more conservative than
the performance criteria
because new facilities
should be designed to a
higher standard.
Gravity Sewers:
• d/D < 0.75 under future peak wet weather flows
• Minimum Velocity = 2 fps for daily dry weather
• Maximum Velocity = 10 fps at peak design flow
• Minimum Pipe Diameter = 8 inches
• Minimum Cover = 6 feet (ground to pipe crown)
Pump Stations: Firm capacity greater than the peak wet
weather flow during the design storm.
Force Mains:
• Minimum/Maximum Velocity: 3 fps /8 fps
• Minimum Cover = 6 feet (ground to pipe crown)
1Peak RDI/I occurs at approximately the same time as peak BWF for most areas of the sewer system. 2d/D = Depth-to-Diameter Ratio representing the depth of flow within the pipe. 3Capacity of the pump station assuming that the largest pump is out of service.
The design and performance criteria selected for sewer master planning efforts vary by agency and are reflective of the level of risk that is acceptable to each agency. Common criteria for several agencies both inside and outside of California were reviewed during the process of selecting the City’s criteria. Ultimately, Santa Clara elected to apply relatively conservative criteria in order to identify all potential projects, recognizing that conditions may change in the future due to variable factors such as sewer condition, additional development, and climate change. However, engineering judgment was used when applying the City of Santa Clara (0012307.00) ES-11 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
performance criteria to avoid identifying capacity deficiencies where gravity sewers showed only minor criteria violations.
Capacity Analysis Scenarios and Results
The capacity analysis is performed using the calibrated hydraulic model to identify sewer facilities that may not have sufficient capacity to convey the predicted flows based on the selected performance criteria. A total of 12 model scenarios were developed to assess system performance and were a combination of the wastewater flow scenario (existing, near-term future, or long-term future), design flow (dry or wet weather), and physical network assumptions (with or without assumed lining of City-identified reinforced concrete sewers likely to be in poor condition) listed in Table ES-6.
TABLE ES-6: SUMMARY OF CAPACITY ANALYSIS MODEL SCENARIOS Wastewater Flow Design Flow Physical Network
Existing Dry Weather Unlined: Current system with no future lining assumed Near-Term Future Wet Weather Lined: Assumes future lining of City-identified RCP trunks in poor condition Long-Term Future
The capacity analysis identified a total of 16 gravity sewer deficiencies, the locations of which are shown in Figure ES-4. In the figure, pipes shown in pink are predicted to surcharge due to “throttle” conditions, indicating that the full capacity of the pipe is less than the predicted peak flow. Pipes shown in purple are predicted to surcharge due to backwater from a downstream throttle condition. A total of 15 capacity improvement projects were developed to relieve the gravity sewer capacity deficiencies identified through the capacity analysis. The project locations and extents are shown in Figure ES-5. Most projects were developed to either replace the existing, capacity-deficient pipe with a larger pipe or to re-direct a portion of flows to other existing sewers with adequate available capacity. Replacement pipes were sized based on the selected design criteria to convey flow for the most conservative model scenario (i.e., long-term future wastewater flow, wet weather design flow, and lined physical network). The number of projects developed (15) is less than the number of capacity deficiencies identified (16) because model runs showed that the Agate Drive deficiency would be relieved once the Calabazas Trunk project was implemented.
The capacity analysis did not identify any pump station or force main capacity deficiencies. The firm and total capacities of each of the City’s seven sewer pump stations were estimated based on basic information, pump settings, pump curves, and system curves provided by the City. Those theoretical capacities were then compared to the model-predicted peak wet weather flows generated from the design storm rainfall event.
Because the theoretical firm capacity of each station did not exceed the model-predicted flow into the station, it was assumed that each station had adequate capacity to convey flows during the most conservative condition evaluated based on the City’s performance criteria. Model-predicted force main velocities were also within the specified performance criteria (i.e., less than 10 fps) during the most conservative condition evaluated, and similarly, no capacity deficiencies were identified. Although the capacity analysis did not identify any pump station capacity deficiencies, the model-predicted peak design flows to the Rabello and Northside Pump Stations during long-term future wet weather conditions (44.8 mgd) are close to the combined firm capacities of these two stations (45.2 mgd). Based on discussions with the City’s Water and Sewer Department, the diversion box upstream of these two pump stations contains a wet well with weir slots that the City has the ability to adjust by dropping in weir boards to control the flow.
Under dry weather conditions and normal settings, approximately 80% of flows go to the Rabello PS and the remaining 20% go to the Northside PS. City staff had not observed flows overtopping the weir boards towards Northside PS, but suspects there may be a gap underneath the weir boards considering SCADA City of Santa Clara (0012307.00) ES-12 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
confirms that flows go to both pump stations. The City should continue to monitor influent flows to these two pump stations as future developments come online and adjust the diversion box weir settings as needed to maximize the available capacity.
Crossman Ave
E Caribbean Dr
237 G2
Sunnyvale
Baylands
County Park
E Arques Ave
Kifer Rd
Stewart Dr
Lakebird Dr
B al zingwood Dr
Tasman Dr
G2
Henderson Ave
Azalea Dr
Reed Ave
Aster Ave
Benton St
Qu
ail Ave
Teal Dr
Bryant Way
Lily Ave
Lillick Dr
Nobili
Ave
Briarwood
Dr
Vireo
Ave
Sequoia Dr
Lorne Way
d Rd
G2
Sunken
Gardens
Golf
Course
Marian A
Peterson Middle
School
Kaiser
Permanente
Santa Clara
Medical Center
Pruneridge Ave
Har vard
Ave
Calvert Dr
N Tantau Ave
allco Pkwy
Stern Ave
Judy Ave
Calvert Dr
Holger Way
N 1st St
Great America Pkwy
Tasman Dr
W Tasman Dr
Gold St
237
Ulistac Natural
Area
Santa
Clara Golf
and
Tennis
Club
Lakeside Dr
Agnew Rd
Agnew Rd
Wals h Ave
Laurelwood Rd
Oakmea
d Pk
wy
Kifer Rd
Norman Ave
Clyde
Ave
Hope Dr
Comstock St
Cheeney
St
Lake shore Dr
Torrance Ave
Tasman Dr
Great A
meri
ca Pkwy
Central Expy
Montague Expy
101
Fairwood Park
Lick Mill Park
California's
Great America
Levi's Stadium
West Valley
College Mission
Campus
Harrison St
Benton St
Pomer
oy A
ve
Pomeroy Ave
Martin Ave
Reeve St
Nobili Ave
Walsh Ave
Chromite Dr
Warburton Ave War burton Ave Scott Blvd
Anna Dr
Calabazas Blvd
Newhall St
Los
Olivos
Dr
Richard Ave
Main St
Mark Ave
Enright Ave
Macha do Ave
Francis Ave
El Sobrante St
Agate Dr
Victoria Ave
Borax Dr Bray Ave
Toledo Ave
Homestead Rd
Bellomy St
Kiely Blvd
Saratoga Ave
Bowers
A
ve
La
fayette St
Monroe St
82 Santa Clara
High School
S A N T A
C L A R A
Wood hams Rd
Northlake Dr
Fo rbes Ave
Forest Ave
Pruneridge Ave
Albany Dr
Harold
Ave
Cronin Dr
Rodonovan
Dr
McKinley Dr
Estella Dr
Rebeiro Ave
Rosita Ave
Saratoga
Ave
Stevens Creek Blvd
Kiely Blvd
N Winchester Blvd
Pruneridge
Golf Club
Coy o te Cree
Ce k
nter Rd
C
ente
r Rd
Cisco Way
Balboa St
Holger Way
E Tasman Dr
N
1st St
237
Gua
dalupe Rive r
Innovation Dr
Aldo Ave
River Oaks Pkwy
Laurelwood Rd
Laurie Av e
Ewert Rd
N 1st
St
E Trimble R
Lick Mill B
lvd
G4
101
Alviso St
Newhall St
Main St
Jackson
St
Emory St
Boxwood Dr
Brokaw Rd
Airport Blvd
Lafayette St
Market St
The Alameda
De La Cruz Blvd
82 Santa Clara
Catholic
Cemetery
PayPal Park
San José Mineta
International
Airport
Santa Clara
University
University Ave
Olive Ave Shasta A
Woodland Ave
Bradley Ave
Bailey Ave
Cherrystone Dr
Kenwood Ave
Elliott St
N Bascom
Ave
Stevens Creek Blvd
Naglee Ave
Westfield Valley
Fair ATM
Agilent
CMC Basin
GAP W
GAP E
Calabazas Trunk
Lafayette St
Bowers Ave Kiely Blvd GAP W
Agilent
GAP E
CMC Basin
Homestead
Victoria Ave
Freedom Circle
Bunker Hill Ln E
Cabrillo Ave
Agate Dr
Legend
±
Figure ES-4
Overview of Capacity
Deficiencies
Sewer Master Plan Update
Figure Exported: 12/27/2024 By: SEstabrook Using: \\woodardcurran.net\shared\Projects\0012307.00 Santa Clara CA Sewer Master Plan Update\wip\C. GIS\3. ArcGIS Pro\SantaClaraSewerMasterPlan2024_Report.aprx 0 0.25 0.5 1
Miles
Modeled Sewers
Surcharge State
<1 (no surcharge)
1 (backwater surcharge)
2 (throttle surcharge)
Project #: 0012307.00
Map Created: December 2024
Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions.
Any reliance upon the map or data contained herein shall be at the users’ sole risk.
Crossman Ave
E Caribbean Dr
237 G2
Sunnyvale
Baylands
County Park
E Arques Ave
Kifer Rd
Stewart Dr
Lakebird Dr
B al zingwood Dr
Tasman Dr
G2
Henderson Ave
Azalea Dr
Reed Ave
Aster Ave
Benton St
Qu
ail Ave
Teal Dr
Bryant Way
Lily Ave
Lillick Dr
Nobili
Ave
Briarwood
Dr
Vireo
Ave
Sequoia Dr
Lorne Way
d Rd
G2
Sunken
Gardens
Golf
Course
Marian A
Peterson Middle
School
Kaiser
Permanente
Santa Clara
Medical Center
Pruneridge Ave
Har vard
Ave
Calvert Dr
N Tantau Ave
allco Pkwy
Stern Ave
Judy Ave
Calvert Dr
Holger Way
N 1st St
Great America Pkwy
Tasman Dr
W Tasman Dr
Gold St
237
Ulistac Natural
Area
Santa
Clara Golf
and
Tennis
Club
Lakeside Dr
Agnew Rd
Agnew Rd
Wals h Ave
Laurelwood Rd
Oakmea
d Pk
wy
Kifer Rd
Norman Ave
Clyde
Ave
Hope Dr
Comstock St
Cheeney
St
Lake shore Dr
Torrance Ave
Tasman Dr
Great A
meri
ca Pkwy
Central Expy
Montague Expy
101
Fairwood Park
Lick Mill Park
California's
Great America
Levi's Stadium
West Valley
College Mission
Campus
Harrison St
Benton St
Pomer
oy A
ve
Pomeroy Ave
Martin Ave
Reeve St
Nobili Ave
Walsh Ave
Chromite Dr
Warburton Ave War burton Ave Scott Blvd
Anna Dr
Calabazas Blvd
Newhall St
Los
Olivos
Dr
Richard Ave
Main St
Mark Ave
Enright Ave
Macha do Ave
Francis Ave
El Sobrante St
Agate Dr
Victoria Ave
Borax Dr Bray Ave
Toledo Ave
Homestead Rd
Bellomy St
Kiely Blvd
Saratoga Ave
Bowers
A
ve
La
fayette St
Monroe St
82 Santa Clara
High School
S A N T A
C L A R A
Wood hams Rd
Northlake Dr
Fo rbes Ave
Forest Ave
Pruneridge Ave
Albany Dr
Harold
Ave
Cronin Dr
Rodonovan
Dr
McKinley Dr
Estella Dr
Rebeiro Ave
Rosita Ave
Saratoga
Ave
Stevens Creek Blvd
Kiely Blvd
N Winchester Blvd
Pruneridge
Golf Club
Coy o te Cree
Ce k
nter Rd
C
ente
r Rd
Cisco Way
Balboa St
Holger Way
E Tasman Dr
N
1st St
237
Gua
dalupe Rive r
Innovation Dr
Aldo Ave
River Oaks Pkwy
Laurelwood Rd
Laurie Av e
Ewert Rd
N 1st
St
E Trimble R
Lick Mill B
lvd
G4
101
Alviso St
Newhall St
Main St
Jackson
St
Emory St
Boxwood Dr
Brokaw Rd
Airport Blvd
Lafayette St
Market St
The Alameda
De La Cruz Blvd
82 Santa Clara
Catholic
Cemetery
PayPal Park
San José Mineta
International
Airport
Santa Clara
University
University Ave
Olive Ave Shasta A
Woodland Ave
Bradley Ave
Bailey Ave
Cherrystone Dr
Kenwood Ave
Elliott St
N Bascom
Ave
Stevens Creek Blvd
Naglee Ave
Westfield Valley
Fair ATM
Agilent
CMC Basin
GAP W
GAP E
Calabazas Trunk
Lafayette St
Bowers Ave Kiely Blvd GAP W
Agilent
Agilent
CMC Basin
Homestead
Victoria Ave
Freedom Circle
Bunker Hill Ln E
Cabrillo Ave
Legend
±
Figure ES-5
Overview of Capacity
Improvement Projects
Sewer Master Plan Update
Figure Exported: 12/27/2024 By: SEstabrook Using: \\woodardcurran.net\shared\Projects\0012307.00 Santa Clara CA Sewer Master Plan Update\wip\C. GIS\3. ArcGIS Pro\SantaClaraSewerMasterPlan2024_Report.aprx 0 0.25 0.5 1
Miles
Modeled Sewers
Capacity Improvement Project
Bunker Hill Ln E
Agilent
Bowers Ave
CMC Basin
Calabazas Trunk
GAP E Trunk
GAP W Trunk
Homestead Rd
Kiely Blvd
Lafayette St
Victoria Ave
Freedom Circle
Cabrillo Extent (Not Actual Project) Project #: 0012307.00 Map Created: December 2024
Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions.
Any reliance upon the map or data contained herein shall be at the users’ sole risk.
City of Santa Clara (0012307.00) ES-15 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
ES-3 Recommended Sewer Capacity Capital Improvement Plan The Sewer Capacity CIP recommended in this study is designed as guidance for the City to provide adequate sewer system capacity for the City’s existing and anticipated future development. Table ES-7 and Table ES-8 provide a summary and detail of the recommended capacity improvement projects, respectively. The wastewater flow, design flow, and physical network triggers listed next to each project in Table ES-8 represent the least conservative condition (i.e., lowest flow and available capacity) that first caused the deficiency to occur. Relative priorities of “1” (highest priority) to “7” (lowest priority) were assigned to each project based on a combination of factors including the wastewater flow trigger, design flow trigger, and physical network trigger, and assumed structural condition. Therefore, projects that address existing deficiencies without future lining assumptions in place were assigned the highest priority because they pose the greatest risk of a sanitary sewer overflow (SSO). Those projects were subsequently scheduled for earlier implementation, assuming a start date in 2025. The remaining projects, which would be triggered by future loading conditions, were assigned an implementation start date of 2035. Projects were also assigned a flow confidence level from “1” (highest confidence) to “5” (lowest confidence) to reflect the level of confidence in the data that were used to calibrate the hydraulic model, forecast flows, and identify deficiencies. Projects which were assigned a confidence level “4” or “5” had no reliable confirmation of model flows; thus, conducting flow monitoring on these project reaches prior to design would provide a greater level of confidence in modeled flows.
The total estimated capital cost of the Sewer Capacity CIP is approximately $100.6 million in 2024 dollars.
These costs include baseline construction costs for new sewer mains and sewer structures using open-cut methods; and cost allowances for project mobilization/demobilization, traffic control, and bypass pumping as needed. The total estimated construction costs also include a 30% allowance for contingencies for unknown conditions, and the total estimated capital cost includes an allowance of 25% of construction cost for engineering, administration, construction management, and legal costs. Costs for lining City-identified RCP trunks are not included in the Sewer Capacity CIP as these are condition-related maintenance costs.
The estimated costs are planning or conceptual level estimates to be used for budgeting purposes only and are considered to have an estimated accuracy range of -30% to +50%. Note that the Sewer Capacity CIP does not include costs for two of the specific developer-driven capacity improvement projects, Patrick Henry Drive (PHD) and Mission Point, as the developers will fund those improvements. Additionally, it is assumed that the City’s overall sewer system CIP will also include costs for condition-related improvements; however, these projects are not addressed in this Master Plan Update report.
TABLE ES-7: SUMMARY OF RECOMMENDED SEWER CAPACITY CIP
Description Quantity Notes
Number of Projects 13 3 to be implemented in 2025; 10 after 2035 Total Length of New Sewers 38,100 LF Approximately 7.2 miles Range of New Sewer Diameters 8” – 48” Standard pipe sizes only (inside diameters) Number of New Weirs 4 Used to modify flow routing
Total Estimated CIP Cost1 $100.6M Based on August 2024 dollars Total Other Costs2
$75K annually
$950K every 7 years
$25K annually
Hydraulic Model Maintenance and Support;
Future Master Plan updates (next in 2029);
Technical Analyses for Model Verification
1Designed to reflect costs derived directly from construction of the capacity improvement projects only. 2Other costs associated with improvement of flow conveyance in the system.
City of Santa Clara (0012307.00) ES-16 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
TABLE ES-8: CAPACITY IMPROVEMENT PROJECT DETAILS
1Projects are numbered from upstream to downstream. Table does not include Project Nos. 10 (Patrick Henry Drive) and 11 (Mission Point) because project costs will be paid for by the developers. 2Pre-project pipe diameters include future lining assumptions. 3Projects are prioritized based on wastewater flow, design flow, and physical network triggers as well as assumed structural condition. 4Rating assigned to validate the need for the project through review of flow monitoring data and reported surcharging and operational issues, and compatibility between flow meter data and the model. Descriptions of the flow confidence levels are as follows: N/A = Not assigned because project would be triggered by entitlement flow or specific development; 1 = Flow meter on or very near to the project reach surcharged during metered storm; 2 = Flow meter on or very near to the project reach confirms flow, but did not surcharge during metered storm; 3 = Flow meter near the project reach (upstream or downstream) confirms flow; 4 = No flow meter near the project reach to confirm flow; 5 = Conflicting flow between meter and model. 5EL = Existing Loads; LTFL = Long-Term Future Loads; DWF = Dry Weather Flow; WWF = Wet Weather Flow; UMN = Unlined Model Network; LMN = Lined Model Network. 6Costs are based on August 2024 ENR CCI of 15367.24 for the San Francisco Area and are Class 5 estimates (planning level).
Project No.1 Project ID Project Location Pre-Project Pipe Diameter(s)2
Project Description Priority3
Flow Confidence
Level4
Wastewater Flow
Trigger5
Design Flow
Trigger5
Physical Network
Trigger
5 Project Cost
6 1 Agilent Tracy Dr, Pomeroy Ave, Homestead
Rd (S Trunk), Kiely Blvd 10 to 22.8-inch 12,313 LF of 15 to 27-inch diameter pipe 7 N/A LTFL (entitlement) DWF UMN $26,942,000 2 Homestead Road N Homestead Trunk from Swallow
Wy to Saratoga Creek 18 to 30-inch 6,407 LF of 24 to 33-inch diameter pipe 3 3 LTFL WWF UMN $17,156,000 3 Kiely Boulevard Orthello Wy to S of El Sobrante St 8-inch 266 LF of 10-inch diameter pipe 6 4 LTFL WWF UMN $513,000
4 Victoria Avenue Fowler Ave & Pomeroy Ave to
Nobili Ave & Victoria Ave 8-inch 764 LF of 10-inch diameter pipe 6 3 LTFL WWF UMN $1,337,000 5 Cabrillo Avenue Halford Ave & Buckley St; St.
Lawrence Dr, W of Lawrence Expwy 8-inch
Flow Diversion Weirs
only. No pipe
replacement.
1 3 EL WWF UMN $154,000
6 CMC Basin Santa Maria Ave & Francis Ave;
Amethyst Dr 8 to 12-inch 3655 LF of 12 to 15-inch diameter pipe 1 1 & 2 EL WWF UMN $7,263,000 7 Bowers Avenue Bowers Ave from Chromite Dr to
Walsh Ave 25.7-inch 2605 LF of 30-inch diameter pipe 4 5 LTFL WWF LMN $8,047,000 8 Calabazas Trunk Calabazas Creek from S of Agate Dr
to Central Expwy 22.8 to 27-inch 2791 LF of 18 to 27-inch diameter pipe 2 5 EL WWF LMN $8,731,000 9 Freedom Circle Mission College Blvd from Freedom
Cir to west of Great America Pkwy 12 to 15-inch 1886 LF of 15-inch diameter pipe 5 N/A LTFL (specific development) DWF UMN $3,830,000 12 GAP West Trunk S of West Tasman Dr to Lafayette St 28.5 to 35.7-inch 4810 LF of 36 to 42- inch diameter pipe 3 2 LTFL WWF UMN $17,781,000
13 GAP East Trunk Old Glory Ln to S of Bunker Hill Ln;
Stars and Stripes Dr 31.4-inch 231 LF of 39-inch diameter pipe 4 2 LTFL WWF LMN $1,002,000 14 Bunker Hill Lane East E of Great America Pkwy 6-inch 107 LF of 8-inch diameter pipe 7 N/A LTFL (entitlement) WWF UMN $301,000 15 Lafayette Street N of Calle del Mundo to S of Great
America Wy 34.2 to 40.3-inch 2290 LF of 42 to 48-inch diameter pipe 3 2 LTFL WWF UMN $7,515,000 TOTAL
ESTIMATED
COST
$100,572,000
City of Santa Clara (0012307.00) ES-17 Woodard & Curran, Inc.
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Implementation Recommendations
The City should begin implementation of the Capital Improvement Program recommended in this Master Plan Update, starting with projects needed to address existing system capacity deficiencies. The following items should be considered in project scheduling and design, and in future updates of the Master Plan:
• The City should consider conducting additional flow monitoring or observation to document flow levels during large storm events at locations in the system where the model predicts significant surcharge or where there is a significant difference between previous flow monitoring conducted and the model results. Flow levels during large storm events should be compared to the water levels simulated by the hydraulic model to verify if the modeling predictions for the design storm seem reasonable, and to confirm the need for and, if necessary, refine project sizing. • The alignments and sizes of all recommended projects should be verified with detailed pre-design analyses, including topographic surveys, geotechnical investigations, utility research, and constructability reviews. Detailed pre-design analyses should consider feasibility of trenchless construction methods including pipe-bursting and Pilot Tube Guided Auger Boring (PTGAB), especially at major roadway, railway, and creek crossings. • The decision to parallel or replace existing sewers should consider the physical condition and remaining useful life of the existing pipelines and laterals; the availability of pipeline corridors for new sewer construction; and operation and maintenance concerns. • Capacity improvement projects triggered by long-term future flow assumptions associated with entitlement agreements would not need to be implemented until the entitled parcel(s) begin to discharge their entitled flow(s).
• The hydraulic model has been developed to assist the City in performing capacity analyses and updating the Master Plan in the future. The model should be kept up to date with any changes to existing sewer connections, development plans, and sewer system facilities.
This Master Plan Update report is intended to be a working document to be refined and updated as additional data and new planning information become available. The capacity assessment should be updated whenever there are major changes in planning assumptions or, at a minimum, every five to ten years.
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Master Plan Report - Draft December 2024
1. INTRODUCTION
This introductory section identifies the background and study objectives for the Master Plan Update, briefly describes the City’s sanitary sewer system and service area and presents an overview of the report’s organization by summarizing the content discussed within each section.
1.1 Background and Study Objectives
Prior to this study, the City last conducted a comprehensive assessment of its wastewater system in its 2016 Sanitary Sewer Master Plan Update1(2016 Master Plan). Of the seven (7) capacity improvement projects recommended in the 2016 Master Plan, three (3) projects were implemented: two (2) of which were operational adjustments to the set points for the Westside and Tasman Pump Stations to eliminate unnecessary backups in the influent gravity sewers, and the third was a capital project to upsize approximately 1,800 feet of 24-inch sewers along the Calabazas Creek trunk between Kifer Road and Scott Boulevard to 27-inch sewers.
Since 2016, in addition to completing a few sewer improvement projects, the City has experienced a significant amount of new development, necessitating an update to the 2016 Master Plan that includes an evaluation of the capacity of the sanitary sewer system to handle existing and future wastewater flows.
Several development reviews have also been completed since the 2016 Master Plan. These development reviews are conducted using the City’s hydraulic model to assess if the sanitary sewer system has enough available system capacity for the individual development to connect to the system.
Thus, the purpose of this study is to build an updated, comprehensive hydraulic model of the City’s sewer system, calibrate the model to current flow monitoring data, and identify needed capacity improvements based on existing and projected future flows. This Master Plan Update summarizes the basis of the sewer flow estimates and the hydraulic model development and calibration process, presents the criteria used for the capacity analysis and the deficiencies identified, and describes the proposed projects to address identified capacity deficiencies. Due to the relatively high rates of I/I in specific areas of the system, this assessment also included identifying areas of higher I/I appropriate for further investigation.
1.2 Sanitary Sewer System and Service Area
Santa Clara is a city of approximately 130,000 people located in central Santa Clara County adjacent to the cities of San Jose, Cupertino, and Sunnyvale and covers approximately 18 square miles. The City’s wastewater system serves approximately 25,000 City customers in its service area (primarily residential users) through approximately 288 miles of sewer pipelines generally ranging from 4 to 48 inches in diameter (including 12 miles of private sewer pipelines) and seven (7) sewage pump stations. The City also has an agreement to convey wastewater flows from a major portion of the Cupertino Sanitary District (CuSD) via a connection at Homestead Road and Swallow Drive. Wastewater flows collected are generally conveyed eastward and northward. A portion of the City’s flow continues eastward to the Trimble Trunk and is conveyed to the City of San Jose’s interceptor sewers on Zanker Road. The remainder of the City’s flow and all the CuSD flow travels northward to the City’s Northside and Rabello Pump Stations, where the flow is pumped to the San Jose/Santa Clara Regional Wastewater Facility (SJ/SC RWF) for treatment and disposal.
A summary of the City’s sanitary sewer system infrastructure is presented in Table ES-1. The City’s sewer system and service area are shown in Figure ES-1.
1 City of Santa Clara, Sanitary Sewer Master Plan Update, RMC Water and Environment, April 2016.
City of Santa Clara (Project 0012307.00) 1-2 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
TABLE 1-1: SUMMARY OF SANITARY SEWER SYSTEM INFRASTRUCTURE Infrastructure Quantity Unit
Sewer Mains (Pipes) 1,456,4001/ 276 Feet / Miles
Manholes 5,500 -
Siphons 34 (59 barrels2) -
Pump Stations 7 -
1Total length is rounded to the nearest one hundred feet. 2Some siphons have multiple barrels: Three (3) siphons have three (3) barrels, 19 siphons have two (2) barrels, and the remaining 12 siphons have a single barrel.
De La Cruz LS
Primavera LS
Westside LS
Rabello PS
Northside PS
Tasman LS
Stadium LS
SC Influent
Junction
Structure
CuSD Flow
Legend
Figure 1-1
Sanitary Sewer System
and Service Area
Sewer Master Plan Update
Figure Exported: 12/27/2024 By: SEstabrook Using: \\woodardcurran.net\shared\Projects\0012307.00 Santa Clara CA Sewer Master Plan Update\wip\C. GIS\3. ArcGIS Pro\SantaClaraSewerMasterPlan2024_Report.aprx City Boundary
Pump Station
Santa Clara Force Mains
San Jose Interceptors
CuSD Joint Usage Sewers
Sewers by Diameter
≤6"
8"-10"
>10"-16"
>16"-24"
≥27"
CSJ Interceptor
(Not Modeled)
San Jose/Santa Clara
Regional
Wastewater Facility
Project #: 0012307.00
Map Created: December 2024
Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions.
Any reliance upon the map or data contained herein shall be at the users’ sole risk. ±
0 0.25 0.5 1
Miles
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Master Plan Report - Draft December 2024
1.3 Report Organization
The contents of each of the sections and appendices of this Master Plan Update report are described below. • Section 1 – Introduction: This introductory section provides background information on the objectives and scope of the Master Plan Update, the City’s sanitary sewer system and service area, and the contents and organization of this report.
• Section 2 – Wastewater Flow Assumptions: This section describes the flow monitoring program and basis for estimating model flows for existing conditions and future conditions with projected development.
• Section 3 – Hydraulic Model Development and Validation: This section describes the modeled sanitary sewer system, development of the hydraulic model network, and the calibration of the hydraulic model for dry and wet weather flow conditions. • Section 4 – System Capacity Analysis: This section defines the basis for the capacity assessment of the system, including the selected design storm and performance criteria used to identify deficiencies, and presents the capacity deficiencies identified based on the model results. The section also identifies areas of the system with high I/I and recommends additional investigations to isolate potential direct inflow sources in those areas. • Section 5 – Recommended Capital Improvement Plan: This section presents the recommended capacity improvement projects based on the results of the system capacity analysis using the calibrated hydraulic model. Each recommended project is documented with a general description, planning level capital cost estimate, relative priority rating, and flow confidence level. • Appendices: The appendices to the report provide additional detailed information to support the findings and recommendations presented in the report sections, including plots of flow monitoring and rainfall data and model calibrations, future land use assumptions, and detailed project descriptions, cost estimates, and figures for capacity improvement projects.
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Master Plan Report - Draft December 2024
2. WASTEWATER FLOW ASSUMPTIONS
This section describes the flow monitoring program and basis for estimating model flows for existing conditions and future conditions with projected development.
2.1 Flow Monitoring Program
To support the development of the hydraulic model and Master Plan Update, a temporary flow monitoring program was conducted as part of this study. The purpose of the flow monitoring program was to obtain data to quantify actual flows and characterize infiltration and inflow (I/I) within the sewer system, and to calibrate the hydraulic model for both dry and wet weather conditions.
2.1.1 Flow Monitoring and Rain Gauge Sites
One critical purpose of a flow monitoring program is to aid in the calibration of the model, which is discussed further in Section 3.3. Considerations for flow meter (FM) placement to support model calibration generally include:
• Isolate areas to characterize flows for model calibration; • Select sites on downstream trunks for flow confirmation; • Align the location with flow meters previously used;
• Further divide tributary areas with suspected high I/I based on previous flow monitoring data to further isolate I/I;
• Prioritize preferred hydraulic conditions (i.e., manholes on a straight line preferred over manholes on bends or with multiple incoming pipes); and • Consider ease of access and safety.
Santa Clara has conducted citywide flow monitoring programs in 2006 and 2015 as part of the City’s sewer system capacity assessment study and sewer master plan, respectively. The City also conducted additional selective flow monitoring in the Chromite-Machado-Cabrillo (CMC) tributary area (an area with suspected high I/I based on previous monitoring programs) as detailed in a September 2020 report1.
The 2022-2023 flow monitoring program for this Master Plan Update included 31 temporary gravity flow meters. Prioritizing the placement of the flow meters in the same locations used for previous monitoring programs is beneficial because it allows for comparison to the previously monitored flows to identify changes over time (e.g., increase in I/I). Therefore, the 2022-2023 program included placement of flow meters in all the same locations as in 2015 except for FM2, which was moved three manholes upstream due to safety concerns, and FM9, which was moved farther downstream to be north of Scott Blvd. The 2022- 2023 program also included installation of 8 additional flow meters that were not part of the 2015 program, including a flow meter along Uranium Drive south of Mead Avenue which the City added onto the initial program. Four (4) rain gauges were also installed during the 2022-2023 program, all in the same locations as the rain gauges installed during 2015 and placed to capture spatial variability of rainfall within the City.
V&A Consulting Engineers (V&A), under sub-contract to Woodard & Curran, installed the flow meters and rain gauges and conducted the monitoring program. The flow meters and rain gauges were installed and 1 Sewer Flow Monitoring and Inflow/Infiltration Study prepared by V&A in September 2020 included flow monitoring at 20 sites conducted during two phases.
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Master Plan Report - Draft December 2024
operational from December 13, 2022 to February 13, 2023 (approximately 9 weeks). The flow meters collected flow depth and velocity data which were used to compute flow rate.
In addition to the 31 temporary flow meter sites, CuSD also maintains a permanent flow meter at the CuSD’s and City’s sewer connection point to monitor CuSD flows discharging to the City’s sewer system. CuSD provided V&A with flow data recorded by the permanent meter for the duration of the flow monitoring period.
The location of the flow monitoring sites and rain gauges are shown in Figure 2-1. The figure also shows the associated tributary area (basin) for each flow meter. Note that some meters were located downstream of other meters. In those cases, the meter tributary areas are “incremental” (areas between the flow meter and tributary basins of the upstream flow meters). Table 2-1 lists the flow meter locations and pipe diameters, and notes if the meter is incremental (i.e., has upstream flow meters). A schematic of the City’s trunk sewer system including the temporary flow meters, pump stations, flow split manholes, and diversion structures is presented as Figure 2-2. Plots of the flow monitoring data, including flow, velocity, and level, are provided as Appendix A.
During the flow monitoring period, V&A visited all the temporary flow monitoring sites approximately monthly to check meter operation and site conditions, obtain field calibration measurements, and download collected data. Field calibration involves taking manual depth measurements and flow velocity measurements using a portable velocity meter. These calibration measurements were compared to and used to adjust monitor-recorded depth and velocity, if needed. Calibration measurements were taken at different times of day to obtain calibration points for the full range of typical diurnal flows.
TABLE 2-1: FLOW METER SITES
FM
ID Site Location MH ID1 Upstream Meter ID(s) Pipe Size (in)2 1 Lafayette St. north of Calle de Mundo S104-28 4, 7-8, 10-12, 14-15, 19- 22, 26-29 36
2 Parking Lot east of Great America Pkwy and
north of Stars and Stripes Dr S104-26 6, 9, 19-20, 29-30 33 3 Lafayette St. north of Calle de Mundo S104-30 5-6, 9-13, 19-21, 24, 26- 31 42
4 Parking lot of Levis Stadium S94-35 -- 24
5 Mission College Blvd. north of Our Lady’s Wy. S83-21 10, 11, 12, 13, 20, 21, 24, 26, 27, 28, 29, 30, 31 33
6 Mission College Blvd. north of Our Lady’s Wy. S83-22 9, 19-20, 29-30 30 7 Upstream of Primavera Lift Station. S105-34 -- 24
8 Lafayette St. north of Montague Expwy. S86-12 11-15, 20-22, 26-29 30 9 Calabazas Creek north of Scott Blvd. S72-17 19, 20, 29 30 10 San Juan Ave. and Monroe St. S52-79 26-27 24
11 Chromite Dr. and Pilot Knob Dr. S53-40 10, 26-28 24
12 Chromite Dr. and Alhambra Dr. S53-23 10-11, 26-28 24 13 Bowers Ave. just north of Bonnie Dr. S53-54 20-21, 29 30 14 South Dr. south of Loma Vista Ln. S54-16 20-21, 29 15 City of Santa Clara (Project 0012307.00) 2-3 Woodard & Curran, Inc.
Master Plan Report - Draft December 2024
FM
ID Site Location MH ID1 Upstream Meter ID(s) Pipe Size (in)2 15 Nvidia Parking lot, west off of Scott Blvd.
south of Central Expwy. S65-50 22 18
16 Central Expwy west of UPRR S67-13 10-12, 14, 20-22, 26-29 27 17 De La Cruz Blvd. north of Martin Ave. (western
sewer) S58-9 22 24
18 De La Cruz Blvd. north of Martin Ave. (eastern
sewer) S58-8 22-23 24
19 North of intersection of Wren Ave. at Kent
Avenue S21-18 -- 24
20 Homestead Rd. west of Cherry Orchard Place S21-47 -- 18 21 Kiely Blvd. north of Hearth Pl. and south of
Kaiser Dr. S23-6 20, 29 24
22 Los Padres Blvd. at Bray Ave. S45-80 -- 18
23 Brokaw Rd. northeast of UPRR S48-31 -- 18
24 Bowers Ave. (southbound) north of Central
Expwy. S63-1 10-13, 20-21, 26-29, 31 33
25 West of De La Cruz Blvd. (southbound) and
east of Walsh Ave. S57-56 10-12, 26- 28 30
26 Machado Ave. east of Santa Cruz Ave. S52-87 -- 21
27 Francis Ave. north of Cabrillo Ave. S43-2 -- 10
28 Amethyst Dr. south of Chromite Dr. and north
of Kearney Ave. S53-46 -- 8
29 Homestead Rd. west of Bond Pl. and east of
Cherry Orchard Pl. S21-55 -- 15
30 Parking lot south of Scott Blvd, north of
Central Expwy., west of Oakmead Village Dr. S72-33 -- 15 31 Uranium Dr. south of Mead Ave. S65-50 -- 10
32 CuSD FM at Homestead Rd. and Swallow Dr. S20-9 -- 15 1 Flow meters were placed on the downstream end of the influent pipe. 2 GIS pipe diameter. Actual diameter as measured by V&A may be slightly different. When manholes have multiple incoming manholes, the largest pipe was monitored.
%
%
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%
%
%
%
%
%
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%%
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%,
23 2&3
1 5
31 22
13 19&20
18 14
28 21
24 6
12 26
10 25
16 29
4 2
15 9A&31
8 9A
11 17
7 20
27 30
3 FM 1
FM 10
FM
11 FM 12
FM 13
FM 14
FM 15
FM 16
FM 17
FM 18
FM 19
FM 2
FM 20
FM 21
FM 22
FM 23
FM 24
FM 25
FM 26
FM 27
FM 28
FM 29
FM
3 FM 30
FM 4
FM 5
FM 6
FM
7 FM 8
FM 9A
FM 31
CuSD Meter
De La
Cruz LS
Westside LS Primavera LS
Rabello PS
Northside PS
Tasman LS
Stadium LS
SC Influent
Junction
Structure
Legend
Figure Exported: 12/31/2024 By: SEstabrook Using: \\woodardcurran.net\shared\Projects\0012307.00 Santa Clara CA Sewer Master Plan Update\wip\C. GIS\3. ArcGIS Pro\SantaClaraSewerMasterPlan2024_Report.aprx Project #: 0012307.00
Map Created: December 2024
Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions.
Any reliance upon the map or data contained herein shall be at the users’ sole risk. % 2014-2015 & 2022-2023 Flow Meter Site
% 2022-2023 Flow Meter Site
%, CuSD Flow Meter Site (FM 32)
City of Santa Clara Boundary
Pump Station
San Jose Interceptors
Trunk Mains
Gravity Main
Force Main
Small Diameter Mains
Flow Meter Basin
1 10
11 12
13 14
15 16
17 18
19&20
2 2&3
20 21
22 23
24 25
26 27
28 29
3 30
31 4
5 6
7 8
9A
9A&24
9A&30
9A&31
Figure 2-1
Flow Monitoring
Program
Sewer Master Plan Update
±
0 0.3 0.6 1.2
Miles
San Jose/Santa Clara
Regional
Wastewater Facility
20-26
21-49
10-29 11-41
103-22 103-23
93-53
83-17
104-21 33”@-7.99
104-22
Primavera PS
Westside PS
93-36
Tasman PS
93-52
83-18
73-7
73-30
63-20
53-34
62-6
62-8
62-10
53-105
61-17
61-16
73-29
32-102
ECR
siphon
32-101
32-8
32-45
33-33 33-34
32-68
22-55 22-64
22-52
23-14
33-63
23-24 23-27 24-32
33-5
15-13
25-85
34-6
104-35
104-37
64-34
57-54
58-12
65-30
58-21
58-11
58-22
57-38
58-23
48-2
47-54
35-2
47-58
Trimble to
San Jose Interceptor
36-83
47-59
47-77
48-3
48-11
38-5
38-4 48-48
57-57
38-14
37-48
48-38
47-30
58-3
68-23 68-20
33-4
54-102
25-9
64-46
64-47
56-2
105-37
104-33
105-35
105-6
105-7
105-36
104-49
104-31
105-27
22 6
4 3
2 Figure 2-2: City of Santa Clara Trunk Sewer System Schematic De La Cruz PS
1 # 2014-2015 Temporary Flow Meter Site
Permanent Flow Meter Site
Pump Station
Flow Split Manhole
Junction Manhole
Rabello PS
104-19
Northside PS
Santa Clara
Influent Structure 1
(San Jose)
52-65
10 41-104 42-100
20-9
5 11
12 13
17 18
23 20-16
19 20
14 Walsh Line
M
M2
M1
97-10
Flow Diversion Structure (e.g., weir)
Stadium PS
86-20
95-133
21 8
7 Flow Direction
High-Level Overflow
63-33
54-101
54-100
64-32
41-125
41-113
42-121
42-123 42-125
M
Santa Clara
Junction Structure
M
42”
42”
36”
42”
Control
Chamber
48”
36”
36”
48” FM
D
C
B
A
E
SJ Interceptors
M
24-62
13-38
13-27
13-55
12-50
23-51
23-28
26-44
35-42
26-70
35-20
35-37
35-25
35-17 36-87
36-1
47-60
47-32
47-55
24 25
28 53-47
29 30
9A
82-9
31 52-5
52-4
52-15
2014-2015 and 2022-2023 Temporary Flow Meter Site
52-80
53-74
26 27
# 2022-2023 Temporary Flow Meter Site
#
9 M
20-10
13-26
53-110
15 16
58-17
58-18
58-7 58-6
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Master Plan Report - Draft December 2024
2.1.2 Flow Monitoring Data
During the flow monitoring program, V&A routinely inspected the flow meters as discussed above, and temporary flow meter data was uploaded on a regular basis to an online portal (Claros). Claros generates tabular reports and graphs of recorded level and velocity, as well as scattergraphs of level versus velocity.
In addition to V&A’s internal data review and quality analysis procedures, Woodard & Curran staff periodically reviewed the preliminary flow meter data over the course of the monitoring program to inspect for changes in flow indicating potential problems with the flow meter (e.g., debris buildup on the sensor), change in system operation, or customer discharges, or response to wet weather events. V&A provided “final” (quality controlled and adjusted data) after the conclusion of the program.
Two (2) of the temporary flow meters in the Chromite Drive and Machado Avenue area (FMs 11 and 28) experienced data loss during the flow monitoring period that coincided with wet weather events. Although the data loss occurred during periods with significant rainfall, there were still data available at these sites from other rainfall events that occurred during the flow monitoring period. V&A used the available data to recreate data for the missing periods.
Figure 2-3 shows typical plots of measured flow and rainfall for one flow meter for the flow monitoring period between December 2022 and February 2023. Plots of the flow monitoring data, including flow, velocity, and level, are provided for all meters as Appendix A.
FIGURE 2-3: PLOT OF TYPICAL FLOW DATA FOR 2022-2023 FLOW MONITORING PERIOD
0.0 0.5
1.0 1.5
2.0 2.5
0.0 3.0
1.0 2.0
3.0 4.0
5.0 6.0
7.0 8.0
9.0 10.0
12/16 12/23 12/30 1/6 1/13 1/20 1/27 2/3 2/10 2/17
Rainfall (in/hr)
Flow (mgd)
Date
FM 3 (S104-30, 42-in)
Flow 2022-23 (mgd)
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Master Plan Report - Draft December 2024
2.1.3 Additional Monitoring for Dry Weather Flow Verification In addition to the systemwide flow monitoring program conducted during the winter of 2022-2023, V&A also performed selective monitoring per direction from the City and Woodard & Curran as described below.
Review of the flow monitoring data versus model dry weather flows revealed that FM 12 was placed in the incorrect location during the initial winter 2022-2023 flow monitoring program. To remedy this, Woodard & Curran and the City requested that V&A collect one week of dry weather flow data at the correct location over the summer to enable confirmation of model dry weather flows.
Per the City’s request, additional dry weather flow monitoring was also performed by V&A at eight (8) FM sites during a 7-day dry period from December 9-15, 2023 (site map included in Appendix E). The purpose of the additional flow monitoring was to confirm if the sewer system’s routing of dry weather flows was in alignment with the City’s normal operating conditions. The City’s desire for confirmation was due to discrepancies observed during the winter 2022-2023 flow monitoring program and the previous flow monitoring program conducted during the winter of 2014-2015, which were identified during the model calibration process and are discussed further in Section 3.3.
2.2 Basis of Hydraulic Model’s Wastewater Flow Estimates This section presents the basis of wastewater flow estimates for the City’s sanitary sewer system. It describes the wastewater flow components used in the hydraulic model and the existing and projected future land uses for the City, which form the basis for generating base wastewater flows that are applied to the model.
Design flow estimates are based on criteria developed for three major flow components discussed below and confirmed through model calibration as described in Section 3.3.
2.2.1 Wastewater Flow Components
Wastewater flows include three components: base wastewater flow (BWF), groundwater infiltration (GWI), and rainfall-dependent infiltration/inflow (RDI/I), as illustrated conceptually in Figure 2-4.
Base Wastewater Flow (BWF)
BWF represents the sanitary and process flow contributions from residential, commercial, institutional, and industrial users of the system. BWF varies throughout the day, but typically follows predictable diurnal patterns depending on the type of land use. (Note: the hydraulic modeling software refers to BWF as “foul flow.”)
Groundwater Infiltration (GWI)
GWI is groundwater that infiltrates into defects in sewer pipes and manholes, particularly in winter and springtime in low-lying areas. GWI is typically seasonal in nature and remains relatively constant during specific periods of the year. However, rainfall typically has long-term impacts on GWI rates, as evidenced by measurable increases in GWI after prolonged periods of rainfall. (Note: the hydraulic modeling software refers to GWI as “baseflow.”)
Rainfall-Dependent Infiltration and Inflow (RDI/I)
RDI/I is storm water inflow and infiltration that enter the system in direct response to rainfall events, either through direct connections such as holes in manhole covers or illegally connected roof leaders or area drains, or, more commonly, through defects in sewer pipes, manholes, and service laterals. RDI/I typically result in short term peak flows that recede relatively quickly after the rainfall ends. The magnitude of RDI/I City of Santa Clara (0012307.00) 2-8 Woodard & Curran, Inc.
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flows are related to the intensity and duration of the rainfall, the relative soil moisture at the time of the rainfall event, and the condition of the sewers.
FIGURE 2-4: WASTEWATER FLOW COMPONENTS
2.2.2 Base Wastewater Flow Estimates
For the City’s Master Plan Update, BWF loads were developed for existing conditions, near-term future development conditions, and long-term future development conditions. Existing loads were developed based on average winter water use data from the City’s customer billing records, and future loads were based mainly on specific, known development and redevelopment projects combined with the City’s 2035 General Plan (GP) development forecast. The loading methodology for existing conditions and projected near-term and long-term future BWF are discussed further in the following subsections. A summary of the BWF loads associated with both existing and future land use conditions is presented in Table 2-2.
TABLE 2-2: SUMMARY OF BWF LOADS FOR EXISTING, NEAR-TERM, AND FUTURE CONDITIONS1 Existing Conditions Future Conditions
Flow Component Existing Load (mgd)2 Near-Term Load (mgd) Long-Term Load (mgd)3 Residential BWF 6.72 10.11 13.58
Non-Residential BWF 4.49 6.09 15.48
Total Average BWF 11.21 16.20 29.06
1Does not include loads from CuSD, which are discussed in subsequent subsections. 2Estimated existing BWF calculated from winter water use data. 3 Includes 5.09 mgd assumed for entitlement agreements, mostly for non-residential land uses.
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2.2.2.1 Existing BWF Loads
Existing BWF was estimated based on actual water billing records exported from the City’s customer billing database. The City’s Information Technology (IT) group used the Esri ArcGIS software (GIS) to add location identifier fields to the raw billing data, including the assessor parcel number (APN) and service address.
Raw billing data were first processed to exclude non-wastewater generating accounts, which consisted of selecting only the billing data records with field “utility_type” equal to “S” for sewer. By isolating the sewer accounts, the metered potable water and recycled water accounts that do not generate sewer discharges (e.g., meters that serve fire, construction, or irrigation uses) were removed. The City also has customers who use domestic wells and/or recycled water; however, the BWF for these customers were assumed to be included in the sewer billing data per conversations with the City’s finance department.
Each account’s BWF was estimated based on the average water use for three winter periods (December through March) between December 2019 and March 2022. Metered water use during the winter months most closely approximates wastewater generation because outdoor water use is at a minimum. Each user was also assigned one of two land use types (i.e., residential or non-residential) according to the account’s use category designation as shown in Table 2-3.
TABLE 2-3: LAND USE CLASSIFICATIONS AND EXISTING BWFS BY USE CATEGORY Assigned Land Use Use Category1 Use Category Description Existing BWF (mgd) Residential SF Single-family residential 3.20
MF Multi-family residential 3.522
Non-Residential
CI Commercial industrial 3.782
MU Municipal 0.46
MJ Major sewer users 0.25
Total 11.21
1Based on billing data field “CustomerType_Category”.
2A portion of the customers assigned to the “CI” use category in the City’s billing database were re-assigned to the “MF” use category for the purpose of estimating BWFs because they represented water use from multi-family residential buildings. Detailed land use descriptions based on the North American Industry Classification System (NAICS) were used to identify these customers.
The billing data were further processed in GIS for the purpose of associating each billing data point with its physical service location. Most water billing records were geocoded according to the APN from the City’s land parcels dataset. Where parcel APN did not match between the parcel shapefile and the water billing data, billing records were geocoded according to service address. A visual assessment of the City’s water meter locations and parcels using GIS confirmed that the data were available for most significantly developed parcels within the City. Figure 2-5 shows the geocoded water billing data by customer type.
The procedure used to determine the loading point of each parcel is discussed in Section 3.2.3.
Existing Flow from Cupertino Sanitary District (CuSD)
CuSD provides sewer services for the majority of City of Cupertino, portions of the City of Saratoga, and several unincorporated areas within Santa Clara County adjacent to San Jose. Most of the flow is discharged into the Santa Clara system via a 27-inch sewer line in Homestead Road; the rest is discharged into the City of San Jose (CSJ) system at various other connection points.
CuSD maintains a permanent flow meter at its discharge point in Homestead Road. Meter data between December 2022 and February 2023 were reviewed and analyzed; based on the raw data, monitored average City of Santa Clara (0012307.00) 2-10 Woodard & Curran, Inc.
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dry weather flow (ADWF) and peak dry weather flow (PDWF), based on the period from December 17-23, 2022, were about 3.6 and 5.7 mgd, respectively. Similar to the declining trend observed for the City, CuSD’s ADWF has also declined over 20% compared to the 2007 estimate of 4.9 mgd but increased slightly compared to the 2015 estimate of 3.5 mgd. The initial reduction can likely be explained by increased water conservation activities in response to drought and increased efficiency of water fixtures over time as new homes are built or existing homes are remodeled.
For the purposes of model calibration (discussed further in Section 3.3), the monitored flows were used as the BWF loads from CuSD in the model and were applied to the model network as inflow hydrographs.
However, the raw CuSD flow data were adjusted (i.e., reduced by approximately 5% by volume, resulting in a revised ADWF closer to 3.45 mgd) when applied to the model because it was suspected that the CuSD flow meter was recording higher than actual flows. The CuSD flow meter was not calibrated prior to or during the City’s flow monitoring period, whereas the temporary meters installed throughout the City were calibrated by V&A several times. Moreover, the summation of flow data recorded at FMs 19, 20, and 29 (downstream of CuSD) was less than the CuSD recorded flows prior to the adjustment.
Legend
Figure 2-5
Water Billing Data
Sewer Master Plan Update
Figure Exported: 12/27/2024 By: SEstabrook Using: \\woodardcurran.net\shared\Projects\0012307.00 Santa Clara CA Sewer Master Plan Update\wip\C. GIS\3. ArcGIS Pro\SantaClaraSewerMasterPlan2024_Report.aprx Project #: 0012307.00
Map Created: December 2024
Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions.
Any reliance upon the map or data contained herein shall be at the users’ sole risk.
City of Santa Clara Boundary
Billing Data
Customer Type
CI - Non-Residential
MF - Residential
MJ - Non-Residential
MU - Non Residential
SF - Residential
±
0 0.25 0.5 1
Miles
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2.2.2.2 Future BWF Loads
Future loads, for both near-term and long-term projected land use conditions, were estimated based on development information tracked by Woodard & Curran, additional development information provided by the City, and unit flow factors developed for the 2016 Master Plan. The development of future load estimates, including the assumed unit flow factors, is discussed further in the following subsections.
Unit Flow Factors for Projected Future Development
Unit flow factors, which are representative of the typical per unit wastewater usage associated with a specific land use type, were referenced for the future load calculations. All unit flow factors used for the calculation are from the 2016 Master Plan and the San José-Santa Clara Regional Wastewater Facility (RWF) sewage coefficient table and are presented in Table 2-4, which also shows the associated density and floor-arearatio (FAR) assumptions where applicable (i.e., for parcels associated with the City’s 2035 General Plan). Unit flow factors were also calculated based on the recent billing data that were used to develop existing BWF loads. The multi-family residential unit flow factors calculated using the recent billing data were around 165 gallons per day per dwelling unit (gpd/DU) on average, which is comparable to the 2016 Master Plan unit flow factor values (i.e., 154 gpd/DU for apartments and 175 gpd/DU for condos and townhomes). However, the single-family residential unit flow factor calculated using the recent billing data (i.e., approximately 175 gpd/DU) was significantly lower compared to the 2016 Master Plan unit flow factor of 245 gpd/DU. The reduction observed in per unit water use consumption for single-family dwellings is reasonable considering that outdoor water use is higher for single-family residential customers and several water use restrictions have targeted outdoor water use and irrigation in response to prolonged drought conditions in California.
However, for the purpose of this Master Plan Update effort, the City elected to use the single-family residential unit flow factor from the 2016 Master Plan, given that this is a planning exercise, and it is a more conservative assumption.
TABLE 2-4: UNIT FLOW FACTORS USED TO ESTIMATE FUTURE BWF LOADS Land Use Category Description Unit Flow Factor2 Density/FAR Assumed3
Very High Density Residential 121 gpd/DU -
Apartments 154 gpd/DU -
Corridor Mixed Use and Community Commercial (Residential) 154 gpd/DU 25 DU/acre Regional Commercial Mixed (Residential) 154 gpd/DU 40 DU/acre Condos and Townhomes 175 gpd/DU -
Corridor Residential 175 gpd/DU -
Single Family Residential 245 gpd/DU -
Office (Low Density) 0.1 gpd/SF -
Agricultural Open Space 0 gpd/SF -
Retail 0.1 gpd/SF -
Community 0.1 gpd/SF -
Amenity 0.1 gpd/SF -
Research and Development (R&D) Office and High-Density Office 0.15 gpd/SF - Daycare 0.183 gpd/SF -
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Land Use Category Description Unit Flow Factor2 Density/FAR Assumed3
Police 0.21 gpd/SF -
Swim center 0.3 gpd/SF -
Retail Mixed or High-Density Retail 0.3 gpd/SF -
Corridor Mixed Use (Non-Residential)1 0.335 gpd/SF -
Regional Commercial Mixed (Non-Residential)1 0.335 gpd/SF - Fitness 0.42 gpd/SF -
Beauty Parlor 0.47 gpd/SF -
Hotel 0.48 gpd/SF or
100 gpd/room -
Medical Office 0.51 gpd/SF -
Restaurant (Small Food Service) 0.9 gpd/SF -
Restaurant (Full Service) 1.04 gpd/SF -
Public (Educational Facilities) 15 gpd/student or
0.21/SF 0.2
Theater 5 gpd/seat -
Assisted Living Facility 77 gpd/bed -
University Residences 70 gpd/bed -
Medium Density Residential 154 gpd/DU 25 DU/acre
High Density Residential 154 gpd/DU 40 DU/acre
Low Density Residential 245 gpd/DU 25 DU/acre
Neighborhood Commercial (Residential) 154 gpd/DU 25 DU/acre Parks/Recreation 0 gpd/SF 0.2
Neighborhood Commercial (Non-Residential) 0.1 gpd/SF 0.3 Community Commercial (Non-Residential) 0.1 gpd/SF 0.4
Regional Commercial (Non-Residential) 0.1 gpd/SF 0.5
Heavy Industrial 0.15 gpd/SF 1.25
Light Industrial 0.15 gpd/SF 0.85
1 Unit Flow factor assumes 25% of full-service restaurants and 75% commercial. 2 gpd = gallons per day. DU = dwelling unit. SF = square foot. 3 Only used for the GP Phase 3 developments. For specific developments, the square footage was provided by the City or the developer.
BWF Loads for Near-Term Future Projected Development
A list of the near-term future development parcels as well as a figure depicting their locations are provided in Appendix B. Near-term future development parcels were identified based on a development tracking spreadsheet that Woodard & Curran created and updated regularly as part of the on-call hydraulic modeling services provided to the City, including near-term future load projections and several development reviews. In January 2023, the City Planning Department reviewed the spreadsheet and City of Santa Clara (0012307.00) 2-14 Woodard & Curran, Inc.
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updated the project development assumptions, including project status and timeline, number of units for projects with residential development and development square footage for projects with non-residential development, where applicable. If the City indicated that a specific development was “approved” or “under construction” as of January 2023, it was assumed to be a near-term future development. City Planning indicated a phased approach would be applied to some of the larger development projects associated with specific plans (e.g., Patrick Henry Drive), in which case a portion of the development was included in the near-term future loading scenario and the remainder was applied to the long-term future development scenario. The land use assumptions (e.g., number of units, office square footage) associated with development projects identified as near-term in the updated tracking spreadsheet were multiplied by the appropriate unit flow factors presented in Table 2-4 to calculate the BWF loads. For near-term specific developments that were also associated with development reviews, the development reviews were referenced to confirm the calculated BWF loads.
When applying the near-term future BWF loads to the model, it was assumed that the existing BWF loads associated with the parcels identified as near-term developments would be replaced.
BWF Loads for Long-Term Future Projected Development
A list of the long-term future development parcels as well as a figure depicting their locations are provided in Appendix B. Long-term future development parcels were identified based on Woodard & Curran’s development tracking spreadsheet discussed above and the City’s 2035 General Plan assumptions. Some of the specific developments in the development tracking spreadsheet were assumed to be long-term future rather than near-term future, mostly in cases where projects were associated with specific plans (e.g., Patrick Henry Drive) and City Planning indicated a phased approach would be applied as discussed in the previous section. Like the near-term BWF loads, the BWF loads associated with the long-term future specific development projects were calculated based on the specific project’s development assumptions and the corresponding unit flow factors. Parcels identified as Phase 3 developments in the City’s 2035 General Plan were also identified as long-term future developments. Some parcels were removed from the original Phase 3 General Plan development parcels dataset, including parcels that were already associated with specific developments and parcels that had been removed from the General Plan based on feedback provided by City Planning. The General Plan designation field (GPLANCRT) of the General Plan parcels shapefile (GeneralPlanParcels_Shapefile.shp) provided by the City was used to assign the appropriate unit flow factors, density, and FAR assumptions to the Phase 3 parcels based on the corresponding land use. The long-term future BWF loads for the Phase 3 parcels were then calculated by applying those assumptions to the square footage (SF) of the parcel. For example, BWF loads for a parcel associated with a GPLANCRT of “Office (High Density)” were calculated by multiplying the area of the parcel by the unit flow factor (0.15 gpd/SF per Table 2-4) and the FAR (1.25 per Table 2-4).
BWFs for the long-term future development scenario also included flow assumptions for entitlement holders that discharge to the City’s sewers. The City is obligated to provide sewer system capacity for entitlement holders up to the flows specified in the entitlement agreements. The City’s billing database records show that many entitlement holders have historically discharged less than their flow entitlements; however, considering the City is required to provide capacity to these users should they have the need to increase their discharges, the long-term future BWF scenario conservatively assumes that all entitlement holders would make use of their full discharge allowances. Flow assumptions for entitlement holders were also included in the City’s 2016 Master Plan. The City reviewed the entitlement flow assumptions that were included in the 2016 Master Plan and updated those assumptions for this Master Plan Update based on available information. The long-term future BWF scenario includes flow assumptions for entitlement holders totaling approximately 5.09 mgd, the vast majority of which is allocated to non-residential land users. In City of Santa Clara (0012307.00) 2-15 Woodard & Curran, Inc.
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limited cases where entitlement flow assumptions were applied to the same parcels with planned future development, the higher flow was applied. Therefore, where entitlement flows were assumed to be less than future flows, the more conservative future flows were used in the model for the long-term future scenario.
The entitlement flow assumptions are documented in Appendix B.
When applying the long-term future BWF loads to the model, it was assumed that the existing BWF loads associated with the parcels identified as long-term developments would be replaced.
Future Projected Flow from Cupertino Sanitary District
Future projected load assumptions for CuSD were incorporated into Santa Clara’s Master Plan Update based on the latest information available from CuSD’s hydraulic model, which was most recently re-calibrated in 2023 by AKEL Engineering. CuSD exported the results from its re-calibrated hydraulic model and provided the flow hydrographs to Woodard & Curran for both near-term and long-term future development projections during both dry weather and wet weather flow conditions. Woodard & Curran created inflow hydrographs based on the results that were exported from CuSD’s re-calibrated model; the magnitude of flows were maintained but the timing was slightly shifted to match the diurnal usage pattern observed in the flow monitoring data and to align the peak wet weather response where applicable. Table 4-6 summarizes the wastewater flow assumptions applied to Santa Clara’s hydraulic model to represent the future projected inflows from CuSD. Note that for the long-term future wet weather flow scenario only, the peak flow was conservatively scaled up to match the contractual limit defined in Santa Clara’s agreement with CuSD which is equal to 13.8 million gallons per day (mgd).
TABLE 2-5: WASTEWATER FLOW ASSUMPTIONS FOR CUSD1
Flow Scenario Average Dry Peak Dry Average Wet Peak Wet (mgd) (mgd) (mgd) (mgd)
Near-Term Future 4.2 6.3 4.6 11.3
Long-Term Future 4.6 6.7 5.9 13.82
1Based on CuSD’s hydraulic model results for a seven (7) day period. 2Assumed to be contractual limit defined in agreement between Santa Clara and CuSD.
2.2.3 Groundwater Infiltration
GWI represents a seasonal increase in wastewater flows due to infiltration into the sewers, typically in lowlying areas or areas close to creeks or other water bodies. In the context of design flow criteria, GWI represents the incremental groundwater infiltration that occurs during the wet weather season which is in addition to the “baseline” groundwater level during the driest months of the year.
GWI is applied in the model as a constant flow in addition to the BWF. The amount of GWI in any particular area of the sewer system is determined during model calibration by comparing the modeled flows to the actual observed dry weather (non-rainfall period) flows at points in the system where flow data are available (e.g., at flow meter sites). Where modeled BWF is noticeably less than monitored dry weather flow by a constant value throughout the day, the difference is assumed to represent GWI. Note that because GWI is seasonal in nature, the modeled GWI is intended to represent a typical GWI rate during the wet weather season (wintertime) rather than a dry season (summertime) GWI. Typical wintertime GWI rates may range from about 100 to 1,000 gallons per acre per day (gpad).
The GWI determined at the monitoring location is then distributed to the upstream meter tributary area on a weighted per-contributing drainage area basis. For Santa Clara, contributing areas for most parcels were set equal to the total area of those parcels. For parcels identified as open space or parks, the contributing City of Santa Clara (0012307.00) 2-16 Woodard & Curran, Inc.
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area was set equal to 0. For parcels identified as schools, the contributing area was assumed to be half of the total area to exclude grass sports fields from the contributing area calculation. All parcels with total areas greater than 5 acres were visually inspected, and the contributing area was zeroed out or reduced if it was determined that significant areas within those parcels did not contribute sewer flows.
2.3 Rainfall-Dependent I/I
RDI/I flows result from rainfall events that produce infiltration and inflow of storm water runoff into the sanitary sewer system. RDI/I can be quantified as the difference between the total flow during and immediately following a storm event and the non-rainfall “base flow” (BWF plus GWI) that is estimated to have occurred during the storm period. RDI/I varies depending on many factors including the magnitude and intensity of the storm event, area topography, type of soil and the degree of soil saturation (due to antecedent rainfall) prior to the storm event, and the condition of the sewers, manholes, and service laterals.
RDI/I is usually expressed as a volume or a percentage of the rainfall volume (termed the “R value”) entering the sewer system from subcatchment contributing areas for each of several flow components representing different response patterns to rainfall events (e.g., fast, medium, slow).
For this modeling effort, five RDI/I response components were used, with each component identified by a percentage of the total RDI/I volume and other parameters that reflect the timing of the flow response, as illustrated conceptually in Figure 2-6. The “fast” component of the hydrograph has the largest impact on the magnitude of the peak wet weather flow response, while the slower components can contribute significantly to the total volume of the RDI/I response. The slowest response component can extend out many days or weeks after the rainfall (alternately, this component could be represented as an increase in GWI). Summing all of the component hydrographs for the duration of the rainfall events results in the total RDI/I hydrograph for that area. R values and hydrograph parameters are determined through the process of wet weather model calibration, discussed in Section 3.5 of this report, in which actual observed rainfall events are simulated in the hydraulic model, and the resulting model hydrographs are compared to the measured flows at the flow meter locations. The RDI/I parameters are adjusted as needed to achieve the best match of modeled to monitored flows. The same calibrated parameters are generally applied to all subcatchments within each meter area. Once calibrated, the model RDI/I parameters can be applied to a design storm to simulate wet weather flows for a design event.
FIGURE 2-6: RDI/I HYDROGRAPH COMPONENTS
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3. HYDRAULIC MODEL DEVELOPMENT AND VALIDATION
This section provides an overview of the hydraulic modeling software and modeling terminology and describes the hydraulic model development and validation process, which includes discussion of the modeled sewer network and facilities as well as the methodology and results associated with calibration of the hydraulic model.
3.1 Hydraulic Modeling Software and Modeling Terminology The modeling software used for development of the Master Plan Update hydraulic model was InfoWorks ICM™ by Autodesk (InfoWorks or ICM), a fully dynamic hydraulic model that was used for Santa Clara’s 2016 Master Plan and the development reviews completed since as well as for many other wastewater systems in the Bay Area, including San Jose and Sunnyvale. InfoWorks uses the implicit method to solve fully dynamic equations of motion (St. Venant equations) for all pipe segments simultaneously at each time step. Detailed information regarding the model software and hydraulic theory (i.e., solution model, equation system, solver, and modeling features) can be found on Innovyze’s help webpage1. Implicit solvers tend to be more stable than explicit solvers with pumping situations and perform better than explicit solvers when dealing with short pipes and loops in the network. Woodard & Curran used its own InfoWorks licenses for this work.
Key hydraulic modeling terms are defined below.
• Network refers to the representation of the physical facilities being modeled. Modeled network components include pipes, manholes, pump stations, etc. • Nodes are primarily manholes, but also include pump station wet wells and outfalls (discharge points from the modeled system). Key data associated with nodes include manhole ground elevations and pump station wet well elevations and cross-sectional areas. • Pipes or conduits are connections between nodes and include both gravity sewers and force mains.
Key data associated with pipes are upstream and downstream node IDs, pipe length, diameter, roughness and headloss factors, and upstream and downstream invert elevations. • Pumps are modeled individually, connecting pump station wet wells with the upstream node of associated force mains. Data associated with pumps include type (e.g., fixed or variable speed), on and off levels, pump capacities, and pump discharge curves. • Subcatchments (also called sewersheds or subbasins) are areas that contribute flow to the modeled sewer network. Data associated with subcatchments include sanitary flow (computed based on population, water use, or other available data), type of diurnal sanitary flow profile (which is a function of land use), infiltration/inflow (I/I) parameters, and the node at which the flow from the subcatchment enters the modeled system.
• Model loads are the flows entering the modeled sewer system from each subcatchment. Model loads include residential and commercial sanitary or BWF, GWI, and RDI/I. As a sum, they represent the total sewer system flow applied to the model. Development of model loads is discussed in Section 2.2.
1 Innovyze Help Menu Documentation on Hydraulic Model Theory, available online at:
https://help2.innovyze.com/infoworksicm/Content/HTML/ICM_ILCM/Hydraulic_Theory.htm.
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• Models are the combination of a modeled network, its associated subcatchments and loads, and other data (e.g., rainfall, diurnal profiles, inflows from other areas, etc.) that comprise a specific model scenario.
3.2 Hydraulic Model Network Development
The hydraulic model network includes the pipes, manholes, and other physical facilities that comprise the modeled sewer system. This section describes the modeled system, including how the sewer facilities are represented in the model, the data attributes that describe the facilities, and the processes for validating those data.
3.2.1 Modeled System
The hydraulic model network developed for this Master Plan Update includes all City-owned pipes within the sanitary sewer system based on the City's GIS data layers. Approximately 12 miles of privately-owned sewer mains were excluded from the model network; therefore, the network consists of about 276 miles of sewers, including 2.7 miles of force mains, or roughly 96% of the total 288 miles of sewer pipeline within the City’s system. The hydraulic model also includes all seven sewage pumping stations. The 2016 Master Plan model was developed to represent the trunk or “backbone” of the sewer system and as such contained approximately 34% (or 94 miles) of the total length of the City’s sewers. Woodard & Curran has maintained and updated the model as sewer improvement projects were implemented, development reviews were requested, or when new network data became available, and this Master Plan Update built on that work by significantly expanding the model network to include all City-owned sewer pipelines. A summary of the pipes and other facilities included in the hydraulic model network is presented in Table 3-1.
TABLE 3-1: SEWER SYSTEM MODEL PIPE SUMMARY
Pipe Diameter (in) Total Length1(ft)
4-6 199,600
8-10 757,800
11-12 222,000
14-16 63,800
17-21 60,100
22-24 48,200
27-29 16,200
30 26,600
>30 47,700
Force Main 14,400
Total Length (feet) 1,456,400
Total Length (miles) 276
Approx. No. of Manholes 5,500
No. of Siphons 34 (59 barrels2)
1Rounded to the nearest hundred feet.
2Some siphons have multiple barrels: Three (3) siphons have three (3) barrels, 19 siphons have two (2) barrels, and the remaining 12 siphons have a single barrel.
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3.2.2 Model Network Construction and Validation
The updated and expanded model network was constructed using the City’s current GIS files of the sewer system, network data from the previous trunk model, 2020 LiDAR ground elevation data, invert data obtained during previous master planning efforts on the small diameter pipes in the system, review of selected record drawings, and limited field investigations.
The GIS shapefiles were used to spatially define the model network, as well as to initially populate asset properties of pipe diameter, pipe length, and pipe material. Invert and rim elevation data were not included in the City’s GIS data but are essential for the model. Therefore, elevation data were obtained from a combination of data sources.
For manhole rims, elevations were assigned based on LiDAR ground elevation data as obtained from the County of Santa Clara1. Elevations were adjusted from NAVD 88 to NGVD 29 by -2.69 feet based on the National Geodetic Survey Coordinate Conversion and Transformation Tool2. The same datum adjustment was used for the 2016 Master Plan and ongoing modeling studies.
For sewer pipe inverts, elevations were populated using the trunk model that was developed for previous master plan efforts (updated on an ongoing basis), small-diameter pipe invert elevations obtained during previous master planning efforts, and depth data from the City’s current GIS (invert estimated by subtracting the depth from the inferred manhole rim), in order of priority. For areas with missing data or in areas where more information was needed to construct the model, additional as-built drawings and field investigations were requested and incorporated.
For sewer pipe diameters, diameters of trunk sewer pipes were assigned based on the trunk model that was developed for previous master plan efforts (updated on an ongoing basis). In select cases where as-builts from specific pipeline lining projects were available (e.g., along the Calabazas trunk near Kifer Road), diameters for lined pipes in the trunk system were updated to reflect their internal diameters. Nominal diameters were assumed for all other pipes. Diameters of small-diameter pipes (not included in the trunk model) were populated from the City’s current GIS.
Several model construction and validation processes were applied to review the initial data that were imported into the model network. The goal of the review was to resolve potential connectivity and data entry errors associated with the GIS data. The result of the model construction and validation process was a fully connected, all-pipe model network representing the City’s physical sewer infrastructure (i.e., pipes, manholes, and special structures) and sewer system inflows from individual parcels throughout the City (i.e., subcatchments).
Model construction and network validation processes included the following:
• The model network was checked for connectivity, i.e., verifying that correct upstream/downstream manholes were identified for each pipe and that there were no missing links in the network.
• Model special structures, such as siphons, sluice gates, weirs, orifices, and pumps were added as described in Section 3.2.4. As-built drawings and field data were used to develop details for 1 Elevation data (2-foot resolution, hydro flattened digital terrain model (DTM) developed based on LiDAR) were published by the County of Santa Clara. The data are available for download here:
https://www.arcgis.com/home/item.html?id=44a391b570a14d4687591fa2e89ebb11 (last updated October 2022). 2 Tool used to determine height adjustments between vertical datums at specific locations of interest. Available online at: https://geodesy.noaa.gov/NCAT/.
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the modeled pump stations, such as wet well elevations and dimensions, number of pumps, pump types, on/off levels, and discharge curves.
• Flow splits (manholes with more than one outlet pipe) were identified, and field verification and/or as-built drawings were requested as needed for further verification of outlet pipe elevations and/or the existence of weirs or other flow diversion structures (refer to Section
3.2.4).
• Manhole and pipeline network data, including rim and invert elevations and pipeline sizes, were assigned based on the following:
▪ In select locations, record drawings for several pipelines were provided by the City and were used to refine elevation, size, and connectivity information. User text fields within the model were used to document the title of the referenced record drawing.
▪ Where invert elevation data were missing or inconsistent with nearby elevations, and not determined through as-built information, interpolated values between known values were used as appropriate or pipe slope was used to infer invert elevations at the upstream ends of the system.
▪ Elevation data in the as-builts were adjusted as needed to the NGVD 29 datum. • Based on the data provided by the sources above, SQL scripts were created and run in order to identify missing or suspect data in the modeled network. Profiles were plotted for each series of pipe segments identified by the scripts to visually check for missing rim or invert elevations, negative or reverse pipe slopes, or abrupt steps up or down in pipe inverts. Where data indicated a discrepancy, an approach to resolve the discrepancy was identified and data were either interpolated or verified through field investigations conducted by the City or as-built drawings. Profiles were also plotted for major trunk sewers and a random subset of sewers within the system to check for missing or suspect data. • The sources of model data (e.g., GIS, as-built/record drawings, survey/field investigation) were documented using “flags” in the model database.
• All gravity pipelines were modeled assuming a Manning’s n of 0.013. • Headloss coefficients for pipelines were inferred using InfoWorks ICM’s “Inference Data Editor” tool, which infers the upstream and downstream headloss coefficients for a pipe based on the planar intersection angle at manholes or other model nodes. Larger intersection angles correspond to higher headloss coefficients.
• Model subcatchments were created to represent parcels and their wastewater discharges as discussed in Section 3.2.3.
3.2.3 Subcatchments
Model subcatchments define areas tributary to the modeled pipe network. For this new all-pipe model, each subcatchment represents a single assessor parcel within the City and “loads” to a pipe or pipes in the modeled network to define where flow from that parcel enters the sewer system. The model includes approximately 23,300 subcatchments, ranging in size from less than 1 acre to 110 acres.
To assign the load pipes to subcatchments, the laterals shapefile from the City’s GIS was used. Load pipes were assigned to subcatchments based on proximity to the closest lateral and were defined as the sewer City of Santa Clara (0012307.00) 3-5 Woodard & Curran, Inc.
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pipe intersecting with the closest lateral. This process assigned a loading pipe to each of the parcels. A visual inspection complemented the process where parcels either did not have a lateral nearby or had multiple laterals. The load pipes are then refined as needed as part of the calibration process (discussed in Section
3.3). Additional discussion of model load development and allocation is provided in Section 2.2.
3.2.4 Special Structures and Flow Splits
Special structures discussed in this section include siphons, gates, weirs, and pumps. Some of these structures were not included in the GIS database of pipes and manholes and therefore were manually added to the model network based on their location. In most cases, the trunk model data were referenced when manually adding these special structures to the model network because most of the special structures were already included in the trunk model used for development reviews. The information specific to each structure that was extracted from the existing trunk network was complemented with information from asbuilt drawings and/or other information provided by the City where available. Overall, the trunk network included 26 weirs, three (3) gates (at two (2) manholes), and one (1) orifice. The all-pipe model network includes the same number of gates and orifices but two (2) additional weirs, so 28 weirs in total.
3.2.5 Pump Stations
All seven (7) of the City’s sewage pumping stations are included in the model network. Pump data summary sheets provided by the City and available record drawings for the lift stations were used to configure the pump stations in the model. Pump on/off levels (converted to elevations) were based on the on/off wet well levels indicated in the pump station summary sheets and as-builts received as part of the 2016 Master Plan and updates received since. Firm capacity (i.e., capacity with the largest pump out of service) and total capacity for each pump station were estimated based on basic information, pump settings, pump curves, and system curves provided by the City. City staff confirmed that none of the pump stations are equipped with variable frequency drives (VFDs). Table 3-2 presents a summary of modeled pump stations, including their estimated firm and total capacities; the calculations for which are provided in Appendix C. The locations of the City’s pump stations are shown in Figure 1-1.
TABLE 3-2: SEWER SYSTEM MODEL PUMP STATION SUMMARY
No. Pump Station Name No. of Pumps Firm Capacity
(mgd)1
Total Capacity
(mgd)
1 Westside 2 1.552 2.532
2 Tasman 2 1.612 2.342
3 De La Cruz 2 1.612 2.522
4 Primavera 6 5.722 6.392
5 Stadium 6 2.562 2.682
6 Rabello 8 25.43 27.94
7 Northside 4 19.83 21.34
1 Firm capacity is defined as the capacity with the largest pump out of service. 2 Theoretical firm and total capacities were estimated for Westside, Tasman, De La Cruz, Primavera, and Stadium Pump Stations based on basic information, pump settings, pump curves, and system curves provided by the City. Refer to Appendix C for detailed calculations for each pump station. 3 Theoretical firm capacities for Rabello and Northside Pump Stations were estimated by Schaaf & Wheeler Consulting Civil Engineers (S&W) as reported in a memorandum titled “Northside and Rabello Pump Station Firm Capacity Evaluation”, dated July 5, 2022.
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4 Theoretical total capacities for Rabello and Northside Pump Stations were estimated using excel spreadsheet tools developed by Schaaf & Wheeler as part of the firm capacity study (refer to footnote 3). System curves for total capacities were estimated based on inferred data because Schaaf & Wheeler did not collect test points with all pumps running.
3.2.5.1 Siphons
The model includes 59 inverted siphons ranging in diameter from 6 to 24 inches; 12 of these are singlebarrel siphons, 38 are part of double-barrel siphons (i.e., at 19 locations), and 9 are triple-barrel siphons (i.e., at 3 locations). Siphons were added to the model as pipes with lengths that reflect actual siphon geometry as obtained from record drawings (sum of downslope, horizontal, and upslope portions). A sample siphon profile is shown in Figure 3-1.
FIGURE 3-1: SAMPLE SIPHON PROFILE
Siphons include downslope, horizontal, and upslope portions, but can be modeled appropriately without the downslope and upslope segments as shown in Figure 3-1. Record drawing information incorporated into the model includes siphon size, invert elevations, segment lengths and locations of the angle points.
Where record drawings were not available, GIS data and/or other information provided by the City was referenced. The following rules were applied in the modeling of siphons:
• Siphons with two or more barrels were represented as separate pipes connecting to the same upstream and downstream nodes with diameter and elevations specified for each pipe. • The friction factor (Manning’s “n”) was set to the same value (0.013) as those specified for gravity pipes elsewhere in the modeled system.
All siphons were assumed to operate under self-cleansing conditions preventing any major sediment buildup. Therefore, no sediment was included in the model siphons.
A list of the siphons included in the hydraulic model and the corresponding assumptions is provided in Appendix F.
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3.2.5.2 Flow Splits
Flow splits, or diversions, are nodes in the system with two or more downstream pipes. The City collected survey information at key flow split locations that Woodard & Curran identified to confirm invert elevations, rim elevations, and flow conditions. The field-collected survey information (data sheets included as Appendix D) was used to update the model attribute information.
Examples of key connections, flow splits, and diversion structures include the following:
• Connection at Homestead Rd. and Swallow Dr. that sends CuSD’s sewer flows to Santa Clara’s system via a 27-inch sewer line.
• Diversion structure modeled to divert part of the flow going to Northside PS and to Rabello PS. • Flume structure modeled to split the flow to the sewer going north on Lawrence Expwy and the sewer going east on Homestead Rd. (refer to Figure 3-2).
FIGURE 3-2: FLUME DIVERSION STRUCTURE TO HOMESTEAD RD. OR LAWRENCE EXPWY.
3.3 Model Calibration Process and Results
This section discusses the model calibration methodology and results. Model calibration is the process of comparing model-simulated flows to monitored (observed) flows and adjusting model parameters until a reasonably good match is achieved. It is not expected that the calibration results in an exact match between modeled and observed flows at every meter at all times; however, modeled flows at most meters should reasonably match the flow volumes and peak flows in the observed data. Model calibration was achieved first through comparing modeled versus metered flows during a dry weather (non-rainfall) period to achieve an accurate prediction of BWF and GWI, and then during a wet weather period to estimate the RDI/I response.
3.4 Dry Weather Flow Calibration
This section discusses the methodology and procedures used to calibrate the model for dry weather flow conditions and presents the results of the dry weather calibration.
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3.4.1 Dry Weather Flow Calibration Methodology
The goal of dry weather calibration is to confirm that the modeled flows and hydraulic conditions are reasonable compared to the metered flows during non-rainfall periods. Dry weather calibration is an iterative process; if legitimate differences are found between modeled and metered flows, these differences are investigated, and adjustments would be made to the modeled flows as appropriate.
The general approach to dry weather flow calibration was as follows:
1) Confirm overall model loads match metered flows. Compare total model flows to metered flows at the most downstream flow meters (FM1, FM2, FM3). If significant discrepancies are identified, review the model loads and billing data for major issues. Investigate and resolve issues. 2) Compare modeled and metered average flows to identify major discrepancies. Starting at the upstream ends of the system and continuing downstream until the model outfall, identify any flow meters where the difference between average modeled and metered flows is greater than 30%. If discrepancies are identified at a meter, review the tributary model loads and associated billing for major issues and/or flow routing at flow splits and diversion structures. Investigate and resolve issues.
3) Compare modeled and metered average flows to identify modest discrepancies. Starting at the upstream ends of the system and continuing downstream until the model outfall, identify any flow meters where the difference between average modeled and metered flows is between 10% and 30%. If discrepancies are identified at a meter, review parcel loading assignments, major dischargers, or need to use a return factor or discharge cap for selected residential customers. Some modest discrepancies in average flows could be due to the need to add GWI, which are considered in conjunction with review of diurnal patterns. Investigate and resolve issues. 4) Compare modeled average flows to pump station SCADA. If hourly pump station SCADA are available, compare the data to modeled flows.
5) Review diurnal patterns. Balance adjustment of diurnal patterns with the need to add constant GWI. Adjust patterns as needed or as available information allows for large users (customers with average water use above 50,000 gpd), permitted industrial dischargers (particularly those with batch discharges), and event venues with highly variable use (e.g., Levi Stadium). 6) Review flow monitoring and model surcharge status. If the model predicts any surcharge during DWF, those locations should be reviewed for potential network data errors.
For meters that are downstream of multiple other meters, a flow balance was performed to confirm that the total upstream metered flow is less than or equal to the downstream metered flow (e.g., if FM 3 is downstream of FM 1 and FM 2, then FM 1 flows + FM 2 flows should be ≤ FM 3 flows).
3.4.1.1 Review of Largest Water Users
A total of 22 accounts with average winter water use of over 50,000 gpd were identified based on the billing data, which are summarized in Table 3-3 and shown in Figure 3-3. During calibration, average flows from these large users were reviewed. Only base flows from the account located at 444 Saratoga Avenue were adjusted from the initial water consumption value presented below to better match modeled and metered flows; base flows were reduced by approximately 20% because an 80% return factor was applied to the FM 22 tributary area as discussed in Section 3.4.2. This adjustment was reasonable given that it is a very large multi-family residential property with a significant amount of irrigated landscape surrounding the 468 units.
Several of these large users were assigned distinct diurnal patterns as discussed in Section 3.4.1.2.
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