Attachment C - Draft Exhibit 1 — Council Water Committee, October 13, 2022

PREPARED BY
Wastewater Master Plan Update

PREPARED FOR
City of Stockton
FINAL/DRAFT REPORT | MONTH YEAR FINAL REPORT | SEPTEMBER 2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
FINAL REPORT | SEPTEMBER 2022
Wastewater Master Plan Update
Prepared for
City of Stockton
Project No. 129-60-20-42
09-07-2022
Project Manager: Patrick Johnston Date
09-07-2022
QA/QC Review: Jeffrey Pelz Date

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
i City of Stockton
Wastewater Master Plan Update
September 2022
Table of Contents
EXECUTIVE SUMMARY ................................ ................................ ................................ .................. ES-1 ES.1 Introduction ............................................................................................................................... ES-1 ES.2 Existing Wastewater Collection System .................................................................................... ES-1 ES.3 Wastewater Flows ..................................................................................................................... ES-4 ES.4 Collection System Planning, Design, and Performance Criteria ................................................ ES-4 ES.5 Hydraulic Model Development .................................................................................................. ES-8 ES.6 Analysis of Existing Flow Conditions .......................................................................................... ES-8 ES.7 Analysis of Future Flow Conditions ......................................................................................... ES-13 ES.8 Recommended Wastewater Collection System CIP ................................................................ ES-23 CHAPTER 1 Introduction ................................ ................................ ................................ .................. 1-1

1.1 Need for the Project ...................................................................................................................... 1-1

1.2 Master Plan Objectives and Priorities ........................................................................................... 1-1

1.3 Previous and Ongoing Studies ....................................................................................................... 1-2

1.3.1 Wastewater Master Plan, 2008 ........................................................................................... 1-3

1.3.2 City of Stockton Gravity Sanitary Sewer Collection System Asset Management and Master Plan, 2018 ........................................................................................................ 1-3

1.3.3 RWCF Capital Improvement and Energy Management Plan, 2011 ..................................... 1-3

1.3.4 RWCF Modifications Project Basis of Design Report, 2019 ................................................. 1-3

1.3.5 Envision Stockton 2040 General Plan, 2018 ........................................................................ 1-4

1.3.6 Wastewater Cost of Service Rate Study, 2019 ..................................................................... 1-5

1.3.7 Water Master Plan Update, 2021 ........................................................................................ 1-5

1.4 Report Organization ...................................................................................................................... 1-5

1.5 Acknowledgements ....................................................................................................................... 1-6 CHAPTER 2 Existing Wastewater Collection System ................................ ................................ .......... 2-1

2.1 Existing Service Area ...................................................................................................................... 2-1

2.1.1 Service Area Description ...................................................................................................... 2-1

2.1.2 Service Connections and Customers .................................................................................... 2-2

2.2 Existing Collection System Facilities .............................................................................................. 2-7

2.2.1 Gravity Sewers ..................................................................................................................... 2-7

2.2.2 Force Mains .......................................................................................................................... 2-7

2.2.1 Pump Stations ...................................................................................................................... 2-9 CHAPTER 3 Existing Wastewater Flows ................................ ................................ ............................ 3-1

3.1 Wastewater Flow Components ..................................................................................................... 3-1

3.1.1 Average Dry Weather Flow .................................................................................................. 3-1

3.1.2 Sanitary Peak Flow ............................................................................................................... 3-1

3.1.3 Infiltration and Inflow .......................................................................................................... 3-1

3.1.4 Peak Wet Weather Flow ...................................................................................................... 3-2

ATTACHMENT C
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DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
ii City of Stockton
Wastewater Master Plan Update
September 2022
Table of Contents

3.2 Flow Metering Locations ............................................................................................................... 3-2

3.3 Rainfall Results .............................................................................................................................. 3-2

3.4 Flow Monitoring Results ................................................................................................................ 3-6

3.4.1 Evidence for Backwater Conditions ..................................................................................... 3-9

3.5 Investigation of Flow Splits .......................................................................................................... 3-14 CHAPTER 4 Collection System Planning, Design, and Performance Criteria ................................ ........ 4-1

4.1 Existing City Planning and Design Standards ................................................................................. 4-1

4.2 Planning and Assessment criteria Used in This Analysis ............................................................... 4-2

4.2.1 Flow Factors for General Plan Land Use Categories ............................................................ 4-3

4.2.2 Modeling of Peak Wet Weather Flow Conditions ............................................................... 4-4

4.2.3 Capacity Assessment of Existing Facilities ........................................................................... 4-6 CHAPTER 5 Hydraulic Model Development ................................ ................................ ...................... 5-1

5.1 Model Construction ....................................................................................................................... 5-1

5.1.1 Modeling Software............................................................................................................... 5-1

5.1.2 Model Geometry .................................................................................................................. 5-1

5.1.3 Assignment of Parcel-Generated Flows to Model Nodes .................................................... 5-4

5.2 Dry Weather Flow Calibration ....................................................................................................... 5-5

5.2.1 Dry Weather Flow Generation ............................................................................................. 5-5

5.2.2 Pandemic Shift Analysis ....................................................................................................... 5-6

5.2.3 Criteria for Dry Weather Flow Calibration ........................................................................... 5-9

5.2.4 Diurnal Flow Patterns .......................................................................................................... 5-9

5.2.5 Metered versus Modeled Dry Weather Flows ................................................................... 5-10

5.3 Wet Weather Calibration ............................................................................................................ 5-11

5.3.1 RTK Method ....................................................................................................................... 5-14

5.3.2 Criteria for Wet Weather Flow Calibration ........................................................................ 5-15

5.3.3 Metered versus Modeled Wet Weather Flows ................................................................. 5-15

5.3.4 Smart Cover Results ........................................................................................................... 5-19

5.3.5 Pump Station Results ......................................................................................................... 5-21

5.4 Design Storm Development......................................................................................................... 5-23 CHAPTER 6 Analysis of Existing Flow Conditions ................................ ................................ ............... 6-1

6.1 Model Results for Existing Conditions ........................................................................................... 6-1

6.2 Modeled Capacity Deficiencies ..................................................................................................... 6-4

6.3 Improvements to Address Existing Capacity Deficiencies ............................................................. 6-4

6.4 Previously Identified System Condition Deficiencies .................................................................... 6-9 CHAPTER 7 Analysis of Future Flow Conditions ................................ ................................ ................ 7-1

7.1 2040 Development and Flow Generation Areas ........................................................................... 7-1

7.1.1 General Plan Major Development Areas ............................................................................. 7-1

7.1.2 General Plan Study Areas ..................................................................................................... 7-1

ATTACHMENT C
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DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
iii City of Stockton
Wastewater Master Plan Update
September 2022
Table of Contents

7.1.3 Additional 2040 Development Areas ................................................................................... 7-1

7.1.4 Unincorporated County Islands ........................................................................................... 7-5

7.1.5 Areas on Septic Tanks .......................................................................................................... 7-5

7.2 Analysis of 2040 Conditions .......................................................................................................... 7-6

7.2.1 System Infrastructure to Serve Future Development .......................................................... 7-6

7.2.2 Model Results for 2040 Conditions ...................................................................................... 7-6

7.2.3 Improvements to Address 2040 Capacity Deficiencies........................................................ 7-8

7.3 Analysis of Buildout Flow Conditions .......................................................................................... 7-13

7.3.1 Buildout Model Flow Assumptions .................................................................................... 7-13

7.3.2 Buildout Model Results ...................................................................................................... 7-14 CHAPTER 8 Recommended Wastewater Collection System CIP ................................ ......................... 8-1

8.1 Cost Estimating Assumptions ........................................................................................................ 8-1

8.2 Recommended Capital Improvements .......................................................................................... 8-2

8.2.1 Pump Station and Force Main Improvements, Existing System .......................................... 8-6

8.2.2 Rehabilitation of Existing Gravity Sewer Facilities ............................................................... 8-7

8.2.3 Capacity Improvements to Existing Gravity Sewer Facilities ............................................... 8-7

8.2.4 Recommended Studies ........................................................................................................ 8-7

8.2.5 Watch List Items .................................................................................................................. 8-7

8.2.6 Projects to be Excluded from the City’s Existing CIP List ..................................................... 8-8

8.2.7 Additional Items Not Included in This Analysis .................................................................... 8-8

8.3 Review of Potential Impacts on Rates and Fees ............................................................................ 8-8

8.4 Conclusions and Recommendations ........................................................................................... 8-10

LIST OF TABLES
Table ES-1. Estimated Wastewater Flow Generation Rates by General Plan Land Use Category .... ES-5 Table ES-2. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, Existing Development Conditions .................................................................................. ES-9 Table ES-3. Theoretical Upsizing Improvements that Would Alleviate Existing Capacity Deficiencies ................................................................................................... ES-10 Table ES-4. City-Identified Pump Stations and Force Mains with Condition-Related Concerns ........................................................................................ ES-13 Table ES-5. Previously Identified Gravity Sewer Condition-Related Deficiencies ........................... ES-14 Table ES-6. Modeled Gravity Sewer Capacity Deficiencies, 2040 Development Conditions, 10-Year, 24-Hour Design Storm ................................................................................... ES-18 Table ES-7. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, 2040 Development Conditions .................................................................................... ES-19 Table ES-8. Modeled Gravity Sewer Capacity Deficiencies, Buildout Development Conditions, 10-Year, 24-Hour Design Storm ................................................................................... ES-20

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
iv City of Stockton
Wastewater Master Plan Update
September 2022
Table of Contents
Table ES-9. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, Buildout Development Conditions ............................................................................................. ES-21 Table ES-10. New Pump Station and Force Main Facilities Needed to Serve Buildout Development ............................................................................................... ES-23 Table ES-11. Recommended Capital Improvement Plan ................................................................. ES-25 Table 2-1. Collection System Tributary Areas ..................................................................................... 2-2 Table 2-2. Summary Information for Stockton Unincorporated Islands ............................................. 2-3 Table 2-3. City of Stockton Land Use and Parcel Information for Systems 1 through 10 ................... 2-6 Table 2-4. Significant Industrial Users, City of Stockton ...................................................................... 2-8 Table 2-5. Gravity Mains by Diameter ................................................................................................. 2-9 Table 2-6. Gravity Mains by Pipe Materia) ........................................................................................ 2-10 Table 2-7.Gravity Mains by Installation Year..................................................................................... 2-10 Table 2-8. Force Main Quantities by Pipe Diameter ......................................................................... 2-13 Table 2-9. Wastewater Pump Station Summary Information ........................................................... 2-14 Table 3-1. Summary of Flow Monitoring Locations ............................................................................ 3-3 Table 3-2. Stockton Temporary Rain Gauge Results, October 2020 through March 2021 ................. 3-5 Table 3-3. Return Period Information, January 27 and 28, 2021 Storm Event ................................... 3-5 Table 3-4. Flow and I&I Statistics ........................................................................................................ 3-7 Table 3-5. Flow Depth and Velocity Statistics ................................................................................... 3-10 Table 4-1 Existing City of Stockton Collection System Flow Factors ................................................... 4-2 Table 4-2. Estimated Wastewater Flow Generation Rates by General Plan Land Use Category ........ 4-5 Table 4-3. Existing Gravity Main Capacity Criteria .............................................................................. 4-7 Table 5-1. Pandemic Shift Analysis Results ......................................................................................... 5-8 Table 5-2. Metered versus Modeled Average Dry Weather Weekday Flows ................................... 5-12 Table 5-3. Metered versus Modeled Peak Dry Weather Weekday Flows ......................................... 5-13 Table 5-4. Metered versus Modeled Peak Dry Weather Flow Depths .............................................. 5-14 Table 5-5. Metered versus Modeled Peak Wet Weather Flows ....................................................... 5-16 Table 5-6. Metered versus Modeled Wet Weather Flow Volumes ................................................... 5-17 Table 5-7. Metered versus Modeled Peak Wet Weather Flow Depths ............................................ 5-18 Table 5-8. SmartCover Results, January 27–28, 2021 ....................................................................... 5-20 Table 5-9. Modeled Pump Station Results, January 27–28, 2021 Calibration Storm ....................... 5-22 Table 5-10. Top Ten RWCF Influent Daily Flow Totals, 2011–2021 .................................................. 5-24 Table 6-1. Modeled Average and Peak Flows for Existing Development Conditions.......................... 6-2

ATTACHMENT C
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DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
v City of Stockton
Wastewater Master Plan Update
September 2022
Table of Contents
Table 6-2. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, Existing Development Conditions...................................................................................... 6-3 Table 6-3. Theoretical Upsizing Improvements that Would Alleviate Existing Capacity Deficiencies ......................................................................................................... 6-6 Table 6-4. Notes and Recommendations for Addressing Identified System Deficiencies, Existing Development Conditions...................................................................................... 6-8 Table 6-5. Previously Identified Gravity Sewer Condition-Related Deficiencies ............................... 6-10 Table 6-6. City-Identified Pump Stations and Force Mains with Condition-Related Concerns ......... 6-11 Table 7-1. Major Development Areas, 2040 General Plan Conditions ................................................ 7-2 Table 7-2. Study Areas, 2040 General Plan Conditions ....................................................................... 7-4 Table 7-3. Additional 2040 Development Areas ................................................................................. 7-5 Table 7-4. Modeled Gravity Sewer Capacity Deficiencies, 2040 Development Conditions, 10-Year, 24-Hour Design Storm ....................................................................................... 7-10 Table 7-5. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, 2040 Development Conditions ........................................................................................ 7-11 Table 7-6. Model Results for 2040 Conditions at Future Pump Station Facilities ............................. 7-12 Table 7-7. Available Flow Capacity in Systems 7 and 8 ..................................................................... 7-12 Table 7-8. Study Area 1 Development Quantities, 2040 vs. Buildout ............................................... 7-13 Table 7-9. Modeled Gravity Sewer Capacity Deficiencies, Buildout Development Conditions, 10-Year, 24-Hour Design Storm ....................................................................................... 7-17 Table 7-10. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, Buildout Development Conditions .................................................................................. 7-18 Table 7-11. Model Results for Buildout Conditions at Future Pump Station Facilities ..................... 7-19 Table 8-1. Recommended Capital Improvement Plan ........................................................................ 8-3

LIST OF FIGURES
Figure ES-1. Collection System Service Areas and Unincorporated Islands ...................................... ES-2 Figure ES-2. Existing Wastewater Collection System ........................................................................ ES-3 Figure ES-3. Flow Metering and Rain Gauge Locations ..................................................................... ES-6 Figure ES-4. Flow Split Investigation Results ..................................................................................... ES-7 Figure ES-5. Modeled Collection System Facilities .......................................................................... ES-11 Figure ES-6. Tentative Improvements to Address Existing Capacity Deficiencies ........................... ES-12 Figure ES-7. Condition-Related Deficiencies Identified by the City ................................................. ES-15 Figure ES-8. Areas of 2040 Development and Flow Generation ..................................................... ES-16

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
vi City of Stockton
Wastewater Master Plan Update
September 2022
Table of Contents
Figure ES-9. Modeled Future Collection System Facilities .............................................................. ES-22 Figure ES-10. CIP Projects and Other Facilities Serving Future Development ................................ ES-28 Figure 2-1. Collection System Service Areas and Unincorporated Islands .......................................... 2-4 Figure 2-2. Existing Wastewater Collection System ............................................................................ 2-5 Figure 2-3. Collection System Pipe Material ..................................................................................... 2-11 Figure 2-4. Collection System Pipe Installation Year ......................................................................... 2-12 Figure 3-1. Flow Metering and Rain Gauge Locations ......................................................................... 3-4 Figure 3-2. RWCF Influent Flows and I&I, January 25 through 30, 2021 ............................................. 3-8 Figure 3-3. Level-Velocity Scatterplots and Correlation Coefficients (R) .......................................... 3-11 Figure 3-4. Flow Split Investigation Results ....................................................................................... 3-15 Figure 4-1. Gravity Sewer Capacity Exceedance Criteria ..................................................................... 4-8 Figure 5-1. Modeled Collection System Facilities ................................................................................ 5-2 Figure 5-2. NOAA Type III Rainfall Distribution, City of Stockton 10-Year Storm, 24-Hour Storm ............................................................................................................... 5-23 Figure 5-3. RWCF Influent Flows, January 10–11, 2017 .................................................................... 5-25 Figure 6-1. Modeled Capacity Deficiencies, 10-Year, 24-Hour Storm, Existing Development Conditions .................................................................................... 6-5 Figure 6-2. Tentative Improvements to Address Existing Capacity Deficiencies ................................ 6-7 Figure 6-3. Collection System Condition-Related Deficiencies ......................................................... 6-12 Figure 7-1. Areas of 2040 Development and Flow Generation ........................................................... 7-3 Figure 7-2. Modeled Future Collection System Facilities .................................................................... 7-7 Figure 7-3. Model Surcharging Results 10-Year, 24-Hour Storm 2040 Development Conditions ...... 7-9 Figure 7-4. Parcel-Based Flow Generation Existing vs. Future .......................................................... 7-15 Figure 7-5. Modeled Surcharging Results 10-Year, 24-Hour Storm Buildout Development Conditions ............................................................................................... 7-16 Figure 8-1. Collection System CIP Projects and Other Future Facilities .............................................. 8-9

ATTACHMENT C
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DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
vii City of Stockton
Wastewater Master Plan Update
September 2022
Table of Contents

LIST OF APPENDICES
Appendix A. Collection System Flow Metering Locations
Appendix B. Collection System Flow Split Locations
Appendix C. Flow Split Survey Notes
Appendix D. Modeled vs. Metered Dry Weather Diurnal Flows Appendix E. Modeled vs. Metered Wet Weather Flows
Appendix F. Modeled vs. Metered Wet Weather Flow Depths Appendix G. Existing City Wastewater Facilities CIP
Appendix H: Wastewater Systems Financial Analysis

LIST OF ACRONYMS AND ABBREVIATIONS
AACE Association for the Advancement of Cost Engineering 8 ABS Acrylonitrile Butadiene Styrene 2-9
ACP Asbestos Cement 2-9
AV Area-velocity 3
CalWater California Water Service 2-2
CCTV Closed-Circuit Television 1-3
CIEMP Capital Improvement and Energy Management Plan 1-2 CIP Capital Improvement Plan 1-2
City City of Stockton 1-1
CIWEM Chartered Institution of Water and Environmental Management 5- CIWQS California Integrated Water Quality System Project 5- D Pipe Diameter 3
d Flow Depth 3
DIP Ductile Iron Pipe 2-9
ENR CCI Engineering News Record Construction Cost Index 8 fps Feet per second 4
FY Fiscal Year 8
General Plan Envision Stockton 2040 General Plan 1-1
GIS Geographic Information System 2-1
gpd Gallons per Day 3
HGL Hydraulic Grade Line 4
I&I Infiltration and inflow 3
LIDAR Laser Imaging, Detection, and Ranging 5-
MH Maintenance Hole 3
NAVD 88 North American Vertical Datum of 1988 5-
NGVD 29 National Geodetic Vertical Datum of 1929 5-
NOAA National Oceanic Atmospheric Administration 3

ATTACHMENT C
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N-129-60-20-42-WP-R-WWMP
viii City of Stockton
Wastewater Master Plan Update
September 2022
Table of Contents
PE Polyethylene 2-9
PF Peaking Factor 3
PS Pump Station 3
PVC Polyvinyl Chloride 2-6
Qa Average Dry Weather Flow 3
Qd Design Flow 4
Qp Peak Wet Weather Flow 3
R Depth-Velocity Correlation 3
RCM Reinforced Plastic Mortar 2-9
RCP Reinforced Concrete 2-9
RDII Rainfall-dependent Infiltration and Inflow 5-
RWCF Regional Wastewater Control Facility 1-2
SIUs Significant Industrial Users 2-6
SOI Sphere of Influence 1-4
SSO Sanitary Sewer Overflow 6
V Velocity 3
VCP Verified Clay Pipe 2-6

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
ES-1 City of Stockton
Wastewater Master Plan Update
September 2022
Executive Summary
ES.1 INTRODUCTION
The purpose of this Wastewater Master Plan Update (Master Plan) for the City of Stockton (City) is to evaluate existing wastewater collection system infrastructure, to address potential impacts of near-term and long -term planned growth , and to develop a comprehensive road map for the City’s wastewater system Capital Im provement Program . The City’s Municipal Utilities Department operates the City’s wastewater collection and treatment systems, which serve customers throughout the City and some outlying areas immediately to the east and south of the City limits.

Completion of the City’s Envision Stockton 2040 General Plan (General Plan), in conjunction with changing wastewater generation rates over time, have created a need to reassess the City’s wastewater collection capacity and treatment infrastructure needs for existing and future conditions. The primary objectives of this Master Plan are: 1) to evaluate historical and existing wastewater flows; 2) to refine collection system performance and planning criteria ; 3) to u pdate and calibrate the City’s wastewater co llection system hydraulic model; 4) to evaluate the need for new wastewater collection system facilities to meet existing, near-term, and buildout needs; and 5) to update and prioritize the City’s Capital Improvement Plan (CIP) for wastewater collection system improvements.

This Master Plan report is organized into the following chapters, which are described briefly in this Executive Summary:
• Chapter 1. Introduction
• Chapter 2. Existing Wastewater Collection System
• Chapter 3. Existing Wastewater Flows
• Chapter 4. Collection System Planning, Design, and Performance Criteria • Chapter 5. Hydraulic Model Development
• Chapter 6. Analysis of Existing Flow Conditions
• Chapter 7. Analysis of Future Flow Conditions
• Chapter 8. Recommended Wastewater Collection System CIP ES.2 EXISTING WASTEWATER COLLECTION SYSTEM
The City of Stockton is the county seat and the largest city in San Joaquin County. According to the California Department of Finance, the population of the City in January 2021 was estimated to be 320,876 residents. The existing City limits encompass an area of 41,777 acres, or approximately 65 square miles.

The existing wastewater collection system service area includes residential, commercial, industrial, municipal, and mixed-use areas within the City, as well as 17 unincorporated areas that are partially or fully enclosed by the Stockton City limits boundary and are referred to as “unincorporated islands”.

The City’s collection system can be separated into 10 existing sub -areas or “syste ms”. The City’s wastewater collection system conveys all flows to the Regional Wastewater Control Facility (RWCF), which is located along the San Joaquin River on the south side of Navy Drive at the western edge of the City. The City’s wastewater collection system comprises just over 1,000 miles of gravity mains ranging from 4-inch diameter to 84 -inch diameter, as well as 35 pump stations and approximately 37 miles of active force mains ranging from 2-inch diameter to 42-inch diameter.

Figure ES-1 shows the existing collection system service areas, City limits, Sphere of Influence, and unincorporated islands. Figure ES-2 shows all 12-inch diameter and larger sewer lines, the locations of all public sanitary sewer pump stations, and the location of the RWCF.

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Colonial Heights
Oakridge-Swenson Park
Stockton
Northeast
Elkhorn
Rancho
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Wagner
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Country Club
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Collection System Service Areas
Unincorporated Islands
City of Stockton Limits
City of Stockton Sphere of Influence
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 2\Figure 2-1. Collection System Service Areas and Unincorporated Islands.mxd - jsteiner - 6/15/2022 1-10
Figure ES-1
Collection System Service Areas
and Unincorporated Islands
City of Stockton
Wastewater Master Plan Update
Notes:

1. 2018 aerial imagery obtained from the USDA Farm Service Agency.

2. City limits based on GIS shapefile obtained from San Joaquin County website.

3. Unincorporated Island boundaries sourced from the City of Stockton Sphere of Influence Municipal Service Review, prepared by PlaceWorks on April 23, 2020.

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M E D I C A L C E N T E R
( M A P L E S T R E E T )
P I XI E WO O D S
G R I N D E R
P U M P
AR C H
AI R PO R T R D
HAR N EY LN
M O R AD A LN
FR EM O N TST
M AI N
ST
EI G H T M I LE R D
DR M AR TI N LU TH ERKI NG JRBLVD CH AR TERW AY
CEN TU R Y
BLVD
BAR BAR ATER R YBLVD
CALI FO R N I A
ST
FI LBER T
ST
PER SH I N G AVE
M AI N ST
CEN TER ST
DAVI S R D
CEN TU R Y
BLVD
M ATH EW S
R D
FAR M I N G TO NR D
LATH R O P
R D
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M O R AD A
LN
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HO W AR DR D
PACI FI C AVE
EL D O R AD O ST
BEN JAM I N H O LT D R
SPER R YR D
W I LSO N
W AY
HU TC H I N S
ST
AI R PO R T W AY
HAM LN
W EBER
AVE
O AK
ST
PAR K
ST
M AI N
ST
M C KI NLEY
AVE
KETTLEM AN LN
HAR N EY
LN
HO LM AN R D
HAM M ER LN
ALPI N EAVE
LATH R O P R D
CO U N TR Y
CLU B BLVD
FR EN C H C AM P R D
G ST
SW AI NR D
M AI N ST
M AR CH LN
THO R N TO N
R D
UN I O N
R D
HAR LAN
R D
NAVY DR
CH ER O KEE R D
LO U I SE AVE
M AR I PO SA R D
G O LD EN
VALLEY PK
M AN TH EY
R D
R O TH R D
AR C H R D
W EST LN
HAR LAN R D
Figure ES-2
Existing Wastewater
Collection System
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 2\Figure 2-2. Existing Wastewater Collection System.mxd - jsteiner - 6/15/2022 C o l l e c t io n S y s t e m S e r vic e A r e a s C it y o f S t o c k t o n S ph e r e o f I nf l u e nc e

TF C W R
U R e g io na l Wa s t e w a t e r C o nt r o l F a c il it y [PS
± P u m p S t a t io ns
1 2 - 2 4 I nc h G r a vit y M a in > 2 4 I nc h G r a vit y M a in > 2 4 I nc h F o r c e M a in
< 1 2 I nc h G r a vit y M a in "d 2 4 I nc h F o r c e M a in
1-10
C it y o f S t o c k t o n L im it s

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Executive Summary
N-129-60-20-42-WP-R-WWMP
ES-4 City of Stockton
Wastewater Master Plan Update
September 2022
Within Systems 1 through 10, parcels designated as Residential land use account for approximately 90 percent of all par cels by count , and approximately 41 percent of all parcels by area, with the large majority of those having a Low-Density Residential land use designation. Of the non-residential land uses, the Commercial category makes up the largest group by parcel count, and the Industrial category makes up the largest group by parcel area. Among the Industrial land use category, there are 54 Significant Industrial Users.

ES.3 WASTEWATER FLOWS
For this Master Plan, a collection system flow monitoring study was conducted from late October 2020 through mid-March 2021. A total of 25 temporary flow meters were deployed in sewer lines at various locations throughout the collection system, as shown in Figure ES-3 and as detailed in Appendix A.

The flow monitoring data were used to perform an assessment of both dry and wet weather flow conditions throughout the City’s collection system. The most significant storm event of the season occurred on January 27–28, 2021, which produced 2.92 inches of rain over 48 hours, and which represents an 8-year return period for a 48-hour duration event. The peak measured flow at the RWCF during this event was 55.4 million gallons per day (mgd).

The flow monitoring program revealed that b ackwater conditions (i.e., gravity sewer surcharging during periods when flows are well below full-pipe capacity) routinely occur at five of the flow metering locations.

These conditions indicate that pumping operations routinely do not keep up with incoming flows at Swenson Pump Station (PS), Waterloo and Roosevelt PS, Cumberland & 5-Mile Creek PS, and 14-Mile Slough PS.

An analysis of collection system flow splits was conducted following field surveys performed in September 2020. The flow split locations are shown in detail in Appendix B, and the field data obtained from the September 2020 surveys are shown in Appendix C. These data were used in the development of the hydraulic model of the City’s collection system. The results of the flow split investigation are summarized in Figure ES-4.

ES.4 COLLECTION SYSTEM PLANNING, DESIGN, AND PERFORMANCE CRITERIA The criteria presented in this Master Plan are considered adjunct to existing City Standards and are not intended to replace or supersede those standards unless specifically stated otherwis e. Key criteria addressed in this Master Plan include flow factors for General Plan land use categories, modeling of peak wet weather flow conditions, and capacity assessment of existing facilities.

Proposed flow factors to be used to estimate flow generat ion for future development are presented in Table ES-1. The flow factors are conservatively estimated using an “upper average” value derived from the flow monitoring data, as described in Chapter 4.

The estimation of peak wet weather flows in the collection system is based on the use of a 10 -year, 24-hour storm event, per standard practice. According to the NOAA, the 10-year, 24 -hour storm for Stockton has a magnitude of 2.43 inches.

For this analysis, g ravity mains are considered undersized if excess surcharging occurs, as defined in Chapter 4. Pump stations are considered undersized if the associated firm capacity (i.e., with the largest pump out of service) is not sufficient to accommodate modeled peak flows. Force mains are considered undersized if the maximum velocity exceeds 8 feet per second (fps) at modeled peak flows.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table ES-1. Es
timated Wastewater Flow Generation Rates by General Plan Land Use Category Land Us
e Parcel Count Area, acres
Average Pa
rcel
Size, acres
Winter Water
Demand,
mgd
Return to
Sewer, mgd
Unit Flow by
Area, gpd/acre
Unit Flow by Pa
rcel,
gpd/parcel
Upper Average
,
gpd/acre
Upper Average
,
gpd/parcel
Proposed
Flow
Factor for Future
Growth, gp
d/acre Notes
Residential 80,
724 15,155 0.19 18.334 16.500 1,089 204 -- -- --
High Density Residential 1,379 615 0.45 1.687 1.518 2,467 1,101 5,772 n/a 6,000 Low Density Residential 72,985 13,331 0.18 14.587 13.128 985 180 1,878 310 2,000 City standard = 300 gpd/unit Medium Density Residential 6,360 1,209 0.19 2.059 1.853 1,533 291 3,230 n/a 3,500 Residential Estate 0 0 -- 0 0 -- -- -- -- 2,000 Assumed same as Low Density Res.

Commercial/Industrial/Institutional 3,556 7,595 2.14 6.317 5.685 748 1,599 -- -- -- Administrative Professional 314 335 1.07 0.435 0.391 1,169 1,247 3,497 n/a 3,500 Commercial 2,050 1,829 0.89 2.107 1.896 1,037 925 2,988 n/a 3,000 Economic and Education Enterprise 0 0 -- 0 0 -- -- -- n/a 1,500 Assumed same as Institutional Industrial 800 3,302 4.13 2.921 2.629 796 3,286 1,846 n/a 2,000 Institutional 42 1,853 44.11 0.676 0.608 328 14,480 1,152 n/a 1,500 Mixed Use 350 277 0.79 0.178 0.160 579 458 1,815 n/a 2,000 Downtown 450 187 0.42 0.409 0.368 1,968 819 -- -- --
Downtown Commercial 342 160 0.47 0.302 0.271 1,698 794 4,366 n/a 4,500 Downtown Industrial 10 5 0.53 0.002 0.002 419 221 557 n/a 2,000 Assumed same as Industrial Downtown High Density Residential 60 17 0.28 0.051 0.046 2,699 765 6,305 n/a 6,500 Downtown Medium Density Residential 38 5 0.13 0.007 0.006 1,157 154 1,973 n/a 3,500 Assumed same as Medium Density Res.

Other 847 4,248 5.02 0.048 0.043 10 51 -- -- --
Open Space/Agriculture 1 7 7.04 0.00002 0.00001 2 15 2 n/a 0 Parks and Recreation 46 940 20.42 0.048 0.043 46 934 162 n/a 200 Not specified 800 3,302 4.13 0 0 0 0 -- n/a TBD
TOTAL 85,577 27,186 0.32 25.059 22.553 -- -- -- -- --
Parcels w/Non-Zero Water Demands
N-129-60-20-4
2-WP-R-WWMP
City of
Stockton
Wastewater Master Plan Update
Last Revised: 2-23-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Figure ES-3
Flow Metering and
Rain Gauge Locations

C i t y of S t oc kt on
W a s t e w a t e r M a s t e r P l a n U p d a t e L a s t S a v e d : 6 / 1 5 / 2 0 2 2 1 0 : 0 5 : 3 9 A M N : \ C l i e nt s \ 1 2 9 S t oc kt on\ 6 0 - 2 0 - 4 2 S t oc kt on W W MP \ G I S \ M X D \ W W M P \ C ha p t e r 3 \ F i gu r e 3 - 1 . F l ow M e t e r i ng a nd R a i n G a u ge L oc a t i ons . m x d : j s t e i ne r !( F l ow M e t e r s
£¥ R a i n G a u ge s
[PS
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TF C W RUR e gi ona l W a s t e w a t e r C ont r ol F a c i l i t y G r a v i t y M a i ns ( D "e 1 2 i nc he s ) F or c e Ma i ns
C i t y of S t oc kt on L i m i t s C i t y of S t oc kt on S p he r e of I nf l u e nc e

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Collection System Service Areas
1
2
3
4
5
6
7
8
9
1 0

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Figure ES-4
Flow Split
Investigation Results

C i t y of S t oc kt on
W a s t e w a t e r M a s t e r P l a n U p d a t e L a s t S a v e d : 6 / 1 5 / 2 0 2 2 1 0 : 1 2 : 4 2 A M N : \ C l i e nt s \ 1 2 9 S t oc kt on\ 6 0 - 2 0 - 4 2 S t oc kt on W W MP \ G I S \ M X D \ W W M P \ C ha p t e r 3 \ F i gu r e 3 - 4 . F l ow S p l i t I nv e s t i ga t i on R e s u l t s . m x d : j s t e i ne r

TF C W RU
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Collection System Service Areas
1
2
3
4
5
6
7
8
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Flow Split Category
!( C onf i r m e d G r a v i t y M a i n F l ow S p l i t !( C onf i r m e d F or c e M a i n F l ow S p l i t !( S u r c ha r ge d / H i gh- F l ow C ond i t i on F l ow S p l i t !( N o S e c ond a r y O u t l e t
TF C W RU R e gi ona l W a s t e w a t e r C ont r ol F a c i l i t y G r a v i t y M a i ns ( D "e 1 2 i nc he s ) F or c e M a i ns
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F ou nd
[PS
± P u m p S t a t i ons
C i t y of S t oc kt on L i m i t s C i t y of S t oc kt on S p he r e of I nf l u e nc e

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Executive Summary
N-129-60-20-42-WP-R-WWMP
ES-8 City of Stockton
Wastewater Master Plan Update
September 2022
ES.5 HYDRAULIC MODEL DEVELOPMENT
The hydraulic model of the City’s collection system was developed using Innovyze InfoSWMM™ software, which is a fully dynamic modeling software package that is well-suited for the City’s collection system due to the existence of flow splits throughout the system that di rect flows into multiple pathways. The hydraulic model of the collection system includes all gravity mains of 12 -inch diameter and larger, plus smaller diameter lines that were previously modeled in and around the Downtown area. The hydraulic model also includes a total of 23 pump stations and their associated force mains. The modeled facilities are shown schematically in Figure ES-5.

Pipe invert elevations are derived from a combination of field survey data and City GIS data, with adjustments applied as described in Chapter 5. Ground surface elevations are derived from a combination of field survey data and LIDAR (Laser Imaging, Detection, and Ranging) data provided by the City.

For existing conditions, flows in the model are generated based on parcel-based water use data from the winter of 2019, with adjustments made to account for return-to-sewer ratios and pandemic shift effects.

The model was calibrated first to dry weather conditions and then to wet weather conditions. The dry weather calibration was based on sewer flow data collected from October and November 2020. The wet weather calibration was based on the storm that occurred on January 27–28, 2021, which produced a peak flow at the RWCF of 55.4 mgd, as noted above . As described in Chapter 5, on two occasions since 2012, RWCF influent flows plateaued as high 73.6 mgd for an extended period, indicating that the limits of the influent flow meter were reached and that the actual peak flows were somewhat higher.

The assignment of parcel-based flows to the model, the calibration process, and the analysis of pandemic effects on flow generations are all described in detail in Chapter 5. Comparisons of m etered versus modeled dry weather diurnal flow patterns for the 25 metering sites and for the RWCF are presented in Appendix D. Comparisons of the modeled versus metered wet weather flows are presented in Appendix E.

Comparisons of the modeled versus metered wet weather flow depths are presented in Appendix F.

Modeled collection system pump station results and flow depth monitoring results from the City’s existing SmartCover® sites for the January 27–28, 2021 calibration storm are presented in Chapter 5. The model was successfully calibrated such that the simulated flows satisfactorily matched the conditions observed during the flow monitoring period based on calibration guidelines developed by the Chartered Institution of Water and Environmental Management (CIWEM).

ES.6 ANALYSIS OF EXISTING FLOW CONDITIONS
For a simulated 10-year, 24-hour design storm at existing development conditions, the model predicts a peak flow of 78.5 mgd at the RWCF, which is consistent with available RWCF influent data from the past ten years, as discussed above. Modeled peak flow results for existing conditions at the 23 modeled pump stations are summarized in Table ES-2. Firm capacity exceedances are indicated for the Cumberland & 5-Mile Slough PS and the Don Avenue & Santiago PS. The maximum force main velocity criterion of 8 fps is not exceeded at any pump stations.

Theoretical pipe upsizing improvements to eliminate gravity sewer capacity deficiencies are listed in Table ES-3 and are shown schematically in Figure ES-6. The improvements are listed as Priority 1 (indicating the potential surcharging to less than 4 feet from the ground surface), Priority 2 (indicating the potential surcharging of 4 feet to 8 feet of the ground surface), and Priority 3&4 (indicating less severe surcharging than Priorities 1 and 2).

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table
ES-2. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, Existing Development Conditions Pump Sta
tion System
Firm
Capacity, mgd
Peak
Flow, mgd (a)
Force Main
Diameter,
in
Maximum Force Main
Velocity, ft/sec
14-Mile Slough 10 (b) 10.59 30 3.3
Alexandria
& 14-Mile Slough 2 1.97 1.21 15 1.5
Arch Road 8 8.70 0.55 24 0.3
Blossom Ranch 2 1.30 0.48 8 2.1
Brookside Estates 10 8.64 2.62 20 1.9
Camanche & Ridgeway 2 2.40 0.87 none --
County Hospital -- 2.16 0.19 dual 10 0.3
Cumberland & 5-Mile Creek 1 4.32 5.73 16 6.3
Don Ave & Santiago 2 0.79 1.31 15 1.7
Drake & Highway 99 4 3.54 3.18 14 4.6
Grupe Business Park 7 0.86 0.036 8 0.2
Kelly & Mosher Slough 1 4.32 1.77 12 3.5
March-Brookside & I-5 2 1.15 0.76 8 3.4
Origone 9 5.18 0.001 16 0.0
Plymouth & 5-Mile Creek 1 1.25 0.49 8 2.2
Sanguinetti 9 15.98 0.24 24 0.1
Sinclair Avenue & Highway 4 7 4.32 0.123 10 0.3
Smith Canal & Fontana 3 37.92 31.34 dual 30 4.9
Swenson (North) 2 20.16 18.42 dual 24 4.5
Thornton & Davis 2 1.22 1.18 8 5.2
Waterloo & Roosevelt 4 2.74 2.59 12 5.1
Weston Ranch 8 15.98 2.60 dual 30 0.4
(a) Excee
dances of pump station firm capacity and the force main velocity criterion of 8 ft/sec are highlighted in yellow. (b) Cannot be calculated
due to unknown pump capacities; see Table 2-9.

N-129-60-20-42-WP-R-
WWMP
City of Stoc
kton
Wastewater Master Plan Update
Last Revised: 06-10-22

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table ES-3. Th
eoretical Upsizing Improvements That Would Alleviate Existing Capacity Deficiencies ID # Des
ignation Priorities System
GIS Year
Constructed
Upstream
MH ID
Upstream
MH Location
Downstream
MH ID
Downstream
MH Location
GIS Pipe
Dia, in
Upsized
Pipe Dia, in
Total
Length, ft
No. of Pipe
Segments
Depth to Pipe
Crown, ft
Maximum
Flow, mgd
Maximum
Surcharge, ft
Minimum
Headspace, ft
Priority 1 Group
1-1 E. Marsh Street sewer 1,2,4 6 1895–1940 32R072 Olympic Circle 33P105 S. Sierra Nevada Street 18 24 7,406 21 4.0 to 10.4 4.04 5.1 0 1-2 El Dorado Street /
S. Center Street sewer 1,2,4 6 1905–1915 37N043 E. 6th Street 36M016 E. Charter Way 16 21,24 2,832 9 10.5 to 12.1 3.54 8.9 0.4 1-3 S. Wilson Way sewer 1,2 6 1947 34P082 E. Worth Street 35P012 Mormon Slough 10,12 21 1,001 5 7.6 to 8.6 2.73 8.1 0 1-4 E. 6th Street sewer 1,2 6 1900 37N034 S. San Joaquin Street 37N043 El Dorado Street 12 18 701 4 10.2 to 10.8 1.89 10.7 0 Priority 2 Group
2-1 E. Main Street sewer 2,4 6 1910–1984 33S033 Anteros Avenue 33Q014 E. Washington Street 12,16 18 7,605 24 7.6 to 10.3 1.74 6.1 2.1 2-2 W. Washington Street /
Port Road 23 sewer 2 5 no data 34J016 west of Port Road 13 36H003 north of Navy Drive 12,15,18 18,21 3,800 9 5.6 to 11.8 2.92 4.9 4.0 2-3 Don Avenue /
Meadow Avenue sewer 2 2 1957–1973 20G060 Santiago Way 21G051 Oak Creek Drive 12 15 2,171 10 8.1 to 9.8 1.44 3.7 4.6 2-4 S. El Dorado Street sewer 2,4 6 1900–1910 35N064 E. Worth Street 36N016 E. Charter Way 12 15 2,184 6 8.9 to 11.5 1.13 1.8 7.1 Priority 3&4 Group
4-1 Market Street sewer 4 5 1900–1920 33M079 S. El Dorado Street 34L002 S. Lincoln Street 16,18 27 2,320 8 11.5 to 16.1 1.82 2.0 11.6 4-2 Church Street /
Pershing Avenue sewer 4 5,6 1917 34L022 S. Harrison Street 35L027 S. Pershing Avenue 24 30 3,992 11 9.8 to 15.0 3.30 1.9 9.5 4-3 Waterloo Road sewer 4 3 1920–1984 29Q063 Williams Street 30P039 Hiawatha Avenue 12,15 15,18 1,834 8 21.9 to 23.7 2.30 1.8 20.1 N-129-60
-20-42-WP-R-WWMP
City of
Stockton
Wastwater Master Plan Update
Last Revised: 6-7-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Last Saved: 6/15/2022 10:16:56 AM N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 5\Figure 5-1. Stockton Wastewater Model Network.mxd : jsteiner [PS
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0 1.50.75
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Gravity Main by Diameter
GM < 12"
GM 12" - 24"
GM > 24"
Force Main by Diameter
FM < 12"
FM 12" - 24"
FM > 24"
TF C W RU Regional Wastewater Control Facility
[PS
±Pump Stations
City of Stockton Limits
City of Stockton Sphere of Influence
Figure ES-5
Modeled Collection
System Facilities
C
ity of Stockton
Wastewater Master Plan Update

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
0 1.250.625
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M O R A D A L N

F R E M O N T S T

M A I N S T

D R M A R T I N

L U T H E R K I N GJ R B L V D

C H A R T E R W A Y

W A S H I N G T O N S T

B A R B A R AT E R R YB L V D

C A L I F O R N I A S T

F I L B E R T
S T

P E R S H I N G A V E

M A I N S T

C E N T E R S T

D A V I S R D

M A T H E W S
R D

H A R D I N GW A Y

F A R M I N G T O NR D

L A T H R O P
R D

A L P I N E A V E

C O T T A G E
A V E

H O W A R DR D

P A C I F I C A V E

E L D O R A D O S T

B E N J A M I N

H O L T D R

S P E R R Y R D

M C K E E

B L V D

W I L S O N
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G O L D E N

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Figure ES-6
Tentative Improvements to
Address Existing Capacity Deficiencies
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 6\Figure 6-2. Existing Deficiencies Improvements.mxd - jsteiner - 7/15/2022 TF C W RU Regional Wastewater Control Facility
[PS
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8 1-10 Collection System Service Areas
X-X Deficiency ID
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TF C W RU
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1-1
1-2
1-3
1-4
2-1
2-2
2-4
4-1
4-2
4-3Proposed Lincoln Street
Pump Station

M A I N
S T

F A R M I N G T O NR D

M A R I P O S A R D

F R E M O N T S T

M A I N S T

M A R K E T S T

D R M A R T I N

L U T H E R K I N GJ R B L V D

C H A R T E R W A Y

W A S H I N G T O N S T

C A L I F O R N I A S T

F I L B E R T S T

P E R S H I N G A V E

P A C I F I C
A V E

C E N T E R S TH A R D I N G W A Y
P O R T1 3 R D

A I R P O R T W A Y

E L D O R A D O S T

W I L S O N W A Y

S I E R R A

N E V A D A S T

W E B E R
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O A K S T

H A Z E L T O NA V E

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ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Executive Summary
N-129-60-20-42-WP-R-WWMP
ES-13 City of Stockton
Wastewater Master Plan Update
September 2022
It should be noted that these theoretical improvements do not necessarily equate to a recommendation to proceed forward with design and construction of replacement sewers. In all cases, system geometry (including pipe depths, diameters, and rim elevations) should be confirmed by field surveys. In addition, it is recommended that the City install flow depth monitoring devices (e.g., SmartCovers®) to monitor for possible surcharging at the locations indic ated in Table 6-4. It is also recommended that the modeled capacity exceedances at the Cumberland & 5 -Mile Slough PS and the Don Avenue & Santiago PS be confirmed through flow metering and/or pump run time logging. In addition, the operational conditions resulting in upstream surcharging at Swenson PS, Waterloo and Roosevelt PS, and 14 -Mile Slough PS should be investigated and corrected where appropriate.

In addition to modeled capacity concerns, the City maintains and updates a C IP list that includes recommended collection system rehabilitation improvements to address condition -related deficiencies.

Condition-related deficiencies involving pump stations and force mains (designated as P -#) are summarized in Table ES-4. Condition -related deficiencies requiring rehabilitation of gravity sewers (designated as R-#) are summarized in Table ES-5. Both groups are presented schematically in Figure ES-7.

It is also recommended that the City undertake a City-wide pump station as sessment to determine whether any other pump stations may require modification or rehabilitation.

Table ES-4. City-Identified Pump Stations and Force Mains with Condition-Related Concerns Designation Facilities Priority City Project No.

P-1 14-Mile Slough PS High UW20022/M20022
P-2 5-Mile Slough Force Main High M18015
P-3 Lincoln Street PS and Force Main High UW24005
P-4 Westside Interceptor Parallel Force Main High UW22004 P-5 Swenson (North) PS High UW24003
P-6 Brookside Estates PS Medium UW23003
P-7 College Park PS Medium UW25003
P-8 Don & Santiago PS Medium UW13010/M13010
P-8 Drake & Hwy-99 PS Medium UW25005
P-10 Kelley & Mosher PS Medium UW24004
P-11 Quail Lakes PS Medium UW21015/M21015
P-12 Thornton & Davis PS Medium UW13009/M13009
P-13 Waterloo & Roosevelt PS Medium UW25004
P-14 Camanche & Ridgeway PS Medium UW25002
P-15 Plymouth & 5 Mile Creek PS Medium UW23001
ES.7 ANALYSIS OF FUTURE FLOW CONDITIONS
Modeled conditions for the 2040 timeframe consist of flows for existing development conditions plus future flows from areas that do not currently discharge to the City’s wastewater collection system. These future areas include General Plan Major Development Areas, General Plan Study Areas, additional 2040 development areas, unincorporated island s, and areas within the City limits currently served by septic tanks. The areas in question are shown on Figure ES-8.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table ES-5. Previous
ly Identified Gravity Sewer Condition-Related Deficiencies Designat
ion Name Extents Existi
ng Pipe Diameter, in Approximate Length, LF Priority City Project No.

R-1 Church Street/Pers
hing Avenue trunk sewer Harrison Street to Navy Drive 24 5,600 High UW17023/M17023 R-2 Mormon Slough trunk sewer Jefferson Street to Worth Street 24 2,700 High UW18030/M18030 R-3 Navy Drive I-5 trunk sewer Anderson Street to Swift Way 42 & 54 1,700 High M17026 R-4 Navy Drive parallel trunk sewers Swift Way to west of Fresno Avenue 24, 30 & 48 8,700 High M15003 R-5 Oak Street trunk sewer Wilson Way to Pershing Avenue 21 & 24 11,000 High UW20016/M20016 R-6 Pershing Avenue sewer Oak Street to Tuxedo Avenue 24 4,300 High UW23008 R-7 Ralph Avenue trunk sewer, Phase 1 Mariposa Road to B Street 30 9,200 High M18024 R-8 Sierra Nevada Street trunk sewer Hazelton Avenue to Worth Street 36 1,100 High UW18029/M18029 R-9 Union Street sewer Harding Way to Oak Street 10 & 12 4,300 High UW21007/M21007 R-10 Worth Street trunk sewer Sierra Nevada Street to Anderson Street 36 8,400 High M18028 R-11 Airport Way trunk sewer San Joaquin Fairgrounds to Ralph Avenue 30 5,800 Medium UW21017/M21017 R-12 Alturas Avenue sewer Quincy Street to Swain Road 12 2,000 Medium UW23010 R-13 E. Bianchi Street/ Pardee Lane sewer Townehome Drive to March Lane 12, 15 & 18 6,900 Medium UW24008 R-14 Harding Way sewer Wilson Street to Union Street 12 1,500 Medium UW25008 R-15 Hazelton Avenue trunk sewer Della Street to Pilgrim Street 24 & 36 1,900 Medium UW24011 R-16 Lincoln Road trunk sewer Pershing Avenue to Alexandria Place 36 3,000 Medium UW21018/M21018 R-17 Longview Avenue sewer El Dorado Street to Pacific Avenue 12 3,200 Medium UW23006 R-18 March Lane trunk sewer I-5 to Brookside Estates PS 24 & 30 8,400 Medium UW25006 R-19 Ralph Avenue trunk sewer, Phase 2 Airport Way to Perlman Drive 42 2,400 Medium UW25012 R-20 Rosemarie Lane sewer Manchester Avenue to Crowne Avenue 12 1,400 Medium UW23014 R-21 Ryde Avenue trunk sewer River Drive to Telegraph Avenue 30 & 36 1,400 Medium UW25009 R-22 Sperry Road/Gibraltar Court sewer Airport Way to Industrial Drive 24 & 27 6,200 Medium UW23009 R-23 Tuxedo Avenue sewer Kensington Way to Orange Street 16 1,900 Medium UW23007 R-24 Backyard and smaller diameter sewers Scribner/7th/Howard/Pilgrim Streets 6 & 8 TBD Medium various N-129-60-
20-42-WP-R-WWMP
City of
Stockton
Wastewater Master Plan Update
Last Revised: 06-09-2022

TF C W RU
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C H A R T E R W A Y

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S T

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S T

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D A V I S R D

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Figure ES-7
Condition-Related Deficiencies
Identified by the CIty
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 6\Figure 6-3. Condition-Related Deficiencies Identified by the City.mxd - jsteiner - 6/15/2022 1 2
3 4
10 8
7 9
6 5
10 8
1-10 Collection System Service Areas
Modeled Gravity Sewer
Modeled Gravity Sewer Identified for Rehab
Unmodeled Gravity Sewer Identified for Rehab (Project R-24) Force Main
Force Main Identified for Rehab
Proposed Force Main
[PS
±Pump Station
[PS
±Pump Station Identified for Rehab
[PS
±Proposed Pump Station
R-4
R-10
R-3
R-8
R-1
R-5
R-7
R-6
R-2
R-18
R-19
R-11
R-9
R-22
R-23
R-15
R-12
R-17
R-13
R-14
R-16
R-21
R-20
Notes:

1. Non-location-specific rehabilitation projects R-25, R-26, and R-27 not shown.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
0 1.50.75
Miles
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Insurance
Auto Auction
Hammer Lane
Hotel
VA Project
AOB-96
Study Area1 Stockton
Northeast
Elkhorn
Rancho San
Joaquin
Wagner Heights
Oakridge-Swenson
CSA-15
Study
Area16
Study Area14
Study Area13
Study Area12
Study Area11
Study Area10
Study Area9Study Area8
Study
Area7Study
Area6Study
Area5
Study Area4
Study Area3
Study Area2
Study Area1
(this portion not expected to develop before 2040)
Study Area15

A R C H

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F R E M O N TS T

M A I N
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E I G H T M I L E R D

D R M A R T I N

L U T H E R K I N GJ R B L V D

C H A R T E RW A Y

W A S H I N G T O N S T

B A R B A R AT E R R YB L V D

F I L B E R T
S T

P E R S H I N G A V E

M A I N S T

C E N T U R Y B L V D

M A T H E W S
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H A R D I N GW A Y

C H E R O K E E
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M A I N
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A L P I N E A V E

L A T H R O P
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C O T T A G E
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P A C I F I C A V E

E L D O R A D O S T

B E N J A M I N H O L T D R

S P E R R YR D

H U T C H I N S
S T

A I R P O R T W A Y

H A ML N

O A K S T

P A R K S T

L A T H R O P R D

M C K I N L E Y
A V E

K E T T L E M A N
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H A R N E Y
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B U C K L E Y

C O V E W A Y

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H A M M E R L N

A L P I N EA V E

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C O U N T R Y

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Weber Grant
El
Dorado-Airport
Crystal Bay
Sanctuary
Delta Cove
Mariposa Road
Community
Westlake
Villages
Cannery
Park
North
Stockton
Projects III
Airpark 599
Tra Vigne
NorCal
Logistics
Center Sanchez-Hoggan
Annexation
University
Park
Mariposa
Industrial Park
South Stockton
Commerce Center
Figure ES-8
Areas of 2040 Development and
Flow Generation
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 7\Figure 7-1. Areas of 2040 Development and Flow Generation.mxd - jsteiner - 6/15/2022 Major Developments
General Plan Study Area
Unincorporated Islands Not Currently Connected
Areas on Septic Tanks to be Sewer Connected
Additional 2040 Flow Contributing Areas
City of Stockton Sphere of Influence
Stockton City Limits

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Executive Summary
N-129-60-20-42-WP-R-WWMP
ES-17 City of Stockton
Wastewater Master Plan Update
September 2022
Modeled future system infrastructure, including pump stations, force mains, and gravity sewer pipes of 12-inch diameter and larger, is shown in Figure ES-9. The indicated infrastructure layout is based on preliminary layout s by recent development project proponent s, or is based on an analysis of surface topography, critical surface features (such as highways, railroads, and stream channels), and sewer pipe depths. The exact configuration of collection system facilities serving future areas is subject to change as development plans proceed.

Modeled system deficiencies for 2040 conditions are only slightly more severe than those shown above for existing conditions. Gravity sewer deficiencies for 2040 conditions are shown in Table ES-6. Pump station results for 2040 conditions are shown in Table ES-7. As shown in Table ES-6, t hree additional gravity sewers show either Priority 2 or Priority 3&4 surcharging for modeled 2040 development conditions that did not surcharge under modeled existing peak flow conditions. As shown in Table ES-7, Don Avenue & Santiago PS, Cumberland & 5 -Mile Slough PS, and Westlake PS are all over capacity at modeled 2040 peak flow conditions, while the force mains for 14 -mile Slough PS and Westlake PS are undersized for modeled 2040 peak flow conditions.

It should be noted that the model may overstate peak flows at the Westlake PS because the tributary development areas have previously been defined to include approximately 87 acres of existing and planned lakes that are designated as Low Density Residential development. Removing such areas from the calculation results in 2040 peak flows much closer to the firm capacities of the pump station and force main.

In addition to evaluating 2040 flow conditions, it is also necessary to consider collection system flows associated with the buildout of the City’s Sphere of Influence. The analysis of buildout flow conditions is needed to ensure that any future upsizing of collection system pipes is adequate to accommodate development consistent with planned future land uses through General Plan buildout.

Development of the buildout model requires adding future flow inputs that are not accounted for in the 2040 conditio ns model, specifically: 1) currently vacant parcels not accounted for in any of the 2040 development areas; and 2) additional flows that may be added to the 2040 development areas after 2040.

As shown in Table ES-8, the number of pipes where the model indicates surcharging is substantially greater for buildout than for 2040 conditions. Specifically, the model shows a total of 14 sewer runs where modeled surcharging is indicated for buildout conditions but not for existing or 2040 conditions.

Buildout model results for existing pump stations are presented in Table ES-9. Buildout model results for future pump stations are presented in Table ES-10. In addition to the stations previously identified as being over capacity for 2040 conditions, the Drake & Highway-99 PS, Smith Canal & Fontana PS, Swenson (North) PS, and Waterloo & Roosevelt PS are all shown as over capacity for buildout peak flow conditions.

Moreover, in addition to the 14 -Mile Slough PS force main and the Westla ke PS force main being undersized for buildout peak flow conditions (as also indicated for 2040 conditions), the Sinclair & Highway-4 PS force main is also shown as being undersized for buildout peak flow conditions.

One issue of note involves the pump st ation location and force main alignment that would serve the Mariposa Road Community development area planned for 2040 and beyond. Previous collection system planning showed the force main alignment along a northerly route through Systems 6 and 5, but this alignment included construction through relatively congested areas. The preferred force main alignment would follow existing major trunk sewer routes either through System 7 or through System 8, as shown in Figure ES-9.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table ES-6.

Modeled Gravity Sewer Capacity Deficiencies, 2040 Development Conditions, 10-Year, 24-Hour Design Storm ID # Designati
on Priorities System
GIS Year
Constructed
Upstream
MH ID
Upstream
MH Location
Downstream
MH ID
Downstream

MH Location
GIS Pipe
Dia, in
Upsized Pipe
Dia, in
Total
Length, ft
No. of Pipe
Segments
Depth to Pipe
Crown, ft
Maximum
Flow, mgd
Maximum
Surcharge, ft
Minimum
Headspace, ft
Priority 1 Group
1-1 E. Marsh Street sewer 1,2,4 6 1895–1940 32R072 Olympic Circle 33P105 S. Sierra Nevada Street 18 24 7,406 21 4.0 to 10.4 4.01 5.3 0 1-2 El Dorado Street /
S. Center Street sewer 1,2,4 6 1905–1915 37N043 E. 6th Street 36M016 E. Charter Way 16 21,24 2,832 9 7.4 to 12.1 3.54 8.9 0 1-3 S. Wilson Way sewer 1,2 6 1947 34P082 E. Worth Street 35P012 Mormon Slough 10,12 21 1,001 5 7.6 to 8.6 2.73 8.1 0 1-4 E. 6th Street 1,2 6 1900 37N034 S. San Joaquin Street 37N043 El Dorado Street 12 18 701 4 10.2 to 10.8 1.89 10.7 0 Priority 2 Group
2-1 E. Main Street sewer 2,4 6 1910–1984 33T029 S. Oro Avenue 33Q014 E. Washington Street 12,16 18 8,756 27 7.6 to 10.3 1.74 6.1 2.1 2-2 W. Washington Street /
Port Road 23 sewer 2,3 5 no data 34J016 west of Port Road 13 36H003 north of Navy Drive 12,15,18 18,21 3,800 9 5.6 to 11.8 2.93 4.9 4.0 2-3 Don Avenue / Meadow
Avenue sewer 2 2 1957–1973 20G060 Santiago Way 21G051 Oak Creek Drive 12 15 2,171 10 8.1 to 9.8 1.59 5.7 2.6 2-4 S. El Dorado Street sewer 2,4 6 1900–1910 35M031 E. Worth Street 36N016 E. Charter Way 12 15 1,815 5 8.9 to 11.5 1.19 2.0 6.9 2-5 Del Norte Street sewer 2,4 5 1949–1959 34K004 Force main outlet 35K030 W. Scotts Avenue 36 42 4,132 12 4.4 to 9.3 22.06 1.3 4.2 Priority 3&4 Group
4-1 Market Street sewer 4 5 1900–1920 33M079 S. El Dorado Street 34L002 S. Lincoln Street 12,14,16,18 18,24 2,320 8 12.4 to 16.1 1.94 2.6 11.2 4-2 Church Street/Pershing
Avenue sewer 4 5 1917 34L022 S. Harrison Street 36L035 Navy Drive 24 30 5,613 15 9.5 to 15.0 3.73 2.3 9.2 4-3 Waterloo Road sewer 4 3 1920–1984 29Q063 Williams Street 30P039 Hiawatha Avenue 12,15 15,18 1,834 8 21.9 to 23.7 2.30 1.8 20.1 4-4 N. Lincoln Street sewer 4 5 1920 33L036 upstream terminus 33L039 N. Lincoln Street 4 8 161 4 14.0 to 14.8 0.18 2.2 11.8 N-C-129-60-
20-42-wp-r-tables-cha7
City of Stockton
Was
tewater Master Plan Update
Last Revised: .6-10-22

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table
ES-7. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, 2040 Development Conditions Pump Sta
tion System
Firm
Capacity, mgd
Peak Flow,
mgd (a)
Force Main

Diameter, in
Maximum Fo
rce Main
Velocity,
ft/sec (a)
14-Mile Slough 10 (b) 30.82 30 9.7
Alexandria
& 14-Mile Slough 2 1.97 1.21 15 1.5
Arch Road 8 8.70 0.92 24 0.5
Blossom Ranch 2 1.30 0.56 8 2.5
Brookside Estates 10 8.64 2.61 20 1.9
Camanche & Ridgeway 2 2.40 0.94 none --
County Hospital -- 2.16 0.20 dual 10 0.3
Cumberland & 5-Mile Creek 1 4.32 5.68 16 6.3
Don Ave & Santiago 2 0.79 1.45 15 1.8
Drake & Highway 99 4 3.54 3.39 14 4.9
Grupe Business Park 7 0.86 0.036 8 0.2
Kelly & Mosher Slough 1 4.32 1.96 12 3.9
March-Brookside & I-5 2 1.15 0.76 8 3.4
Origone 9 5.18 0 16 0.0
Plymouth & 5-Mile Creek 1 1.25 0.49 8 2.2
Sanguinetti 9 15.98 4.70 24 2.3
Sinclair Avenue & Highway 4 7 4.32 0.123 10 0.3
Smith Canal & Fontana 3 37.92 37.36 dual 30 5.9
Swenson (North) 2 20.16 18.89 dual 24 4.7
Thornton & Davis 2 1.22 1.13 8 5.0
Waterloo & Roosevelt 4 2.74 2.60 12 5.1
Westlake 10 4.35 5.18 12 10.2
Weston Ranch 8 15.98 5.53 dual 30 0.9
(a) Excee
dances of pump station firm capacity and the force main velocity criterion of 8 ft/sec are highlighted in yellow. (b)
Cannot be calculated due to unknown pump capacities; see Table 2-9.

N-C-129-60-20-41-WP-R-
TABLES-CHA7
City of Stoc
kton
Wastewater Master Plan Update
Last Revised: 06-10-22

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table ES-8. Modeled Gr
avity Sewer Capacity Deficiencies, Buildout Development Conditions, 10-Year, 24-Hour Design Storm ID # De
signation Priorities System
GIS Year
Constructed
Upstream
MH ID
Upstream
MH Location
Downstream
MH ID
Downstream
MH Location
GIS Pipe
Dia, in
Total
Length, ft
No. of Pipe
Segments
Depth to Pipe
Crown, ft
Maximum
Flow, mgd
Maximum
Surcharge, ft
Minimum
Headspace, ft
Priority 1 Group (Ex. And 2040 Conditions)
1-1 E. Marsh Street sewer 1,2,4 6 1895–1940 32R072 Olympic Circle 33P105 S. Sierra Nevada
Street 18 7,406
21 4.0 to 10.4 4.34 5.9 0
1-2 El Dorado Street /
S. Center Street sewer 1,2,4 6 1905–1915 37N043 E. 6th Street 36M016 E. Charter Way 16 2,832 9 7.4 to 12.1 3.58 10.0 0 1-3 S. Wilson Way sewer 1,2 6 1947 34P082 E. Worth
Street 35P012 Mormon Slough 10,12 1,001 5 7.6 to 8.6 2.97

8.1 0
1-4 E. 6th Street 1,2 6 1900 37N034 S. San Joaquin
Street 37N043 El Dorado
Street 12 701 4 10.2 to 10.8 1.77 10.7 0
Priority 2 Group (Ex. & 2040 Conditions)
2-1 E. Main Street sewer 2,4 6 1910–1984 33T029 S. Oro Avenue 33Q014 E. Washington Street 12,16 8,756 27 7.6 to 10.3 1.95 8.2 0
2-2 W. Washington Street /
Port Road 23 sewer 2,3 5 no data 34J016 west of Port
Road 13 36H003 north of Navy
Drive 12,15,18 3,800 9 5.6 to 11.8 2.92 5.2 3.6
2-3 Don Avenue / Meadow
Avenue sewer 2 2 1957–1973 20G060 Santiago Way 21G051 Oak Creek Drive 12 2,171 10 8.1 to 9.8 1.75 8.4 0 2-4 S. El Dorado Street sewer 2,4 6 1900–1910 35M031 E. Worth Street 36N016 E. Charter Way 12 1,815 5 8.9 to 11.5 1.20 2.9 6.1 2-5 Del Norte Street sewer 2,4 5 1949–1959 34K004 Force main outlet 35K030 W. Scotts
Avenue 36 4,132 12 4.4 to 9.3 21.19 3.3 1.9
Priority 3&4 Group (Ex. & 2040 Conditions)
4-1 Market Street sewer 4 5 1900–1920 33M079 S. El Dorado Street 34L002
S. Lincoln Str
eet 12,14,16,
18 2,320 8 12.4 to 16.1 1.98

4.1 9.5
4-2 Church Street/Pershing
Avenue sewer 4 5 1917 34L022 S. Harrison
Street 36L035 Navy Drive 24 5,613 15 9.5 to 15.0 4.62 3.9 8.2 4-3 Waterloo Road sewer 4 3 1920–1984 29Q063
Williams Str
eet 30P039 Hiawatha
Av
enue 12,15 1,834 8 21.9 to 23.7 2.57 2.9 19.0
4-4 N. Lincoln Street sewer 4 5 1920 33L036 upstream
terminus 33L039 N. Lincoln
Street 4 161 4 14.0 to 14.8 0.05 1.8 12.4
Buildout-Only Group
B-1 Sierra Nevada Street
sewer 1,2 3,6 1895–1900 32P048 E. Lindsay
Street 33P105 E. Sonora Street 18 3,312 9 5.1 to 10.5 3.69 6.2 0 B-2 Church Street trunk sewer 4 5,6 1895–1985 33P105 E. Sonora Street 34L037 S. Harrison
Street 27 9,558 27 9.4 to 13.0 7.59 2.5 8.8
B-3 Mormon Slough sewer 2,4 6 1956 34Q037 E. Jefferson
Street 34P088 Worth Street 24 2,617 5 4.7 to 18.6 7.08 3.7 1.2 B-4 Worth Street trunk sewer 4 6 1920–1945 34P088 S. Sierra Nevada Street 35L034 W. Anderson
Street 36 8,502 17 6.7 to 20.8 14.71 3.0 4.2
B-5 Navy Drive west trunk
sewer (42") 1,2,4 5 1997 34G023 San Joaquin
River crossing 36H902 RWCF 42 4,602 12 7.8 to 14.2 63.52 13.8 0 B-6 Oak Street trunk sewer 2,4 3 1900–1958 31P131 Grant Street 33K010 McNabb Place 21,24 8,444 25 8.8 to 11.8 4.49 2.2 7.4 B-7 N Pershing Avenue trunk
sewer 2,4 3 1958 33K010 Oak Street 31K106 Tuxedo Avenue 20,24 4,260 21 9.1 to 16.2 5.40 1.5 7.7 B-8 Oro Avenue / Horner
Avenue 1,2,4 4,6 1984 33T027 E. Main Street 32S052 S. Drake Avenue 12,18 2,817 10 21.5 to 25.8 4.34 10.2 11.3 B-9 Oak Creek Drive / Park
Woods Drive 4 2 1957 21G062 Meadow
Avenue 22G031 Bonniebrook
Drive 12 1,511 8 10.6 to 12.6 1.23 1.3 9.5
B-10 Union Street sewer 2,3 3 1890–1918 30N015 Harding Way 32N016 Oak Street 10,12 3,305 8 6.1 to 10.7 1.00 1.0 5.1 B-11 A.G. Spanos Boulevard
sewer 2,4 10 1993–2006 14F017 Thornton Road 16F018 Whistler Way 24 4,399 14 13.7 to 16.9 7.68 5.8 9.4 B-12 Weber Avenue sewer 3,4 5 1920 33L067 Mormon
Slough 33L048 N. Lincoln
Street 6,8 1,791 7 6.3 to 12.7 0.52 2.0 5.9
B-13 Navy Drive west trunk
sewer (30") 2 5 1959 34G016 San Joaquin
River crossing 36H007 RWCF 30,36 4,080 9 4.6 to 10.2 24.62 2.2 5.4 B-14 S. Airport Way sewer 1,2,4 8 1974 45R005 S. Longe Street 42R024 Sperry Road 18 5,022 16 7.5 to 12.3 15.20 12.9 0 B-15 Performance Drive 1,2 8 1974 44Q001 Aviation Drive 44R013 S. Airport Way 12 2,073 6 3.6 to 9.4 1.22 8.2 0 N-C-129-60
-20-42-wp-r-tables-cha7
City of Sto
ckton
Wastewater Master Plan Update
Last Revised: 06-10-22

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table
ES-9. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, Buildout Development Conditions Pump Sta
tion System
Firm
Capacity, mgd
Peak Flow,
mgd (a)
Force Main

Diameter, in
Maximum Fo
rce Main
Velocity,
ft/sec (a)
14-Mile Slough 10 (b) 60.58 30 19.1
Alexandria
& 14-Mile Slough 2 1.97 1.23 15 1.5
Arch Road 8 8.70 4.39 24 2.2
Blossom Ranch 2 1.30 0.66 8 2.9
Brookside Estates 10 8.64 2.72 20 1.9
Camanche & Ridgeway 2 2.40 1.20 none --
County Hospital -- 2.16 0.89 dual 10 1.3
Cumberland & 5-Mile Creek 1 4.32 6.10 16 6.8
Don Ave & Santiago 2 0.79 1.60 15 2.0
Drake & Highway 99 4 3.54 4.34 14 6.3
Grupe Business Park 7 0.86 0.397 8 1.8
Kelly & Mosher Slough 1 4.32 1.86 12 3.7
March-Brookside & I-5 2 1.15 0.76 8 3.4
Origone 9 5.18 2.16 16 2.4
Plymouth & 5-Mile Creek 1 1.25 0.49 8 2.2
Sanguinetti 9 15.98 8.83 24 4.3
Sinclair Avenue & Highway 4 7 4.32 1.58 10 4.5
Smith Canal & Fontana 3 37.92 44.30 dual 30 7.0
Swenson (North) 2 20.16 20.23 dual 24 5.0
Thornton & Davis 2 1.22 1.20 8 5.3
Waterloo & Roosevelt 4 2.74 3.46 12 6.8
Westlake 10 4.35 5.03 12 9.9
Weston Ranch 8 15.98 10.03 dual 30 1.6
(a) Excee
dances of pump station firm capacity and the force main velocity criterion of 8 ft/sec are highlighted in yellow. (b)
Cannot be calculated due to unknown pump capacities; see Table 2-9.

N-C-129-60-20-41-WP-R-
TABLES-CHA7
City of Stoc
kton
Wastewater Master Plan Update
Last Revised: 06-10-22

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
0 1.50.75
Miles
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±[PS
±
[PS
± [PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
§¨¦5
ÄÆ4
ÄÆ99
Gateway
PS
Sanctuary
PS
Newton
Road PS
Mariposa
PS
System 8
PSTidewater
PS
Priest
Road PS
Mariposa Road PS Force MainSystem 7 Alignment
Mariposa Road PS Force MainSystem 8 Alignment A R C H

A I R P O R T R D

H A R N E Y
L N

M O R A D A L N

F R E M O N TS T

M A I N S T

E I G H T M I L E R D

D R M A R T I N

L U T H E R K I N GJ R B L V D

C H A R T E R W A Y

W A S H I N G T O N S T

B A R B A R AT E R R YB L V D

C A L I F O R N I A S T

F I L B E R T
S T

P E R S H I N G A V E

M A I N S T

C E N T E R S T

D A V I S R D

C E N T U R Y B L V D

G U I L D
A V E

H A R D I N GW A Y

F A R M I N G T O NR D

U N I O N
R D

S T O C K T O N S T

A L P I N E A V E

L A T H R O P
R D

C O T T A G E
A V E

P A C I F I C A V E

E L D O R A D O S T

B E N J A M I N H O L T D R

S P E R R YR D

W I L S O N
W A Y

H U T C H I N S
S T

A I R P O R T W A Y

H A ML N

W E B E R
A V E
O A K
S T

P A R K S T

M A I N S T

C H E R O K E E
L N

M C K I N L E Y
A V E

K E T T L E M A N L N

H A R N E Y
L N

B U C K L E Y

C O V E W A Y

H O L M A N R D

M A I N S T

H A M M E R L N

A L P I N EA V E

L A T H R O P R D

C O U N T R Y

C L U B B L V D

F R E N C H C A M P R D

L O W E R S A C R A M E N T O R D

W I L S O N
W A Y

S W A I NR D

M A R C H L N

T H O R N T O N R D

R E Y N O L D SR A N C H P K

H A R L A N
R D

N A V Y D R M A R I P O S A R D

G O L D E N

V A L L E Y P K

M A N T H E Y
R D

R O T H R D

A R C H R D

W A T E R L O O R D

W E S T L N

P O R T O F

S T O C K T O N E Y

H A R L A N R D
24"
15"
18"
15"
12"
24"
21"
18"
15"
27"
27"
30"
15"
12"
27"
8"
12"
15"
12"
12"
15"
15"
42"
12"
36"
12"
21"
12"
18"
24"
18"
15"
12"
24"
30"
36"
12"
18"
12"
15"
15"
24"
12"
15"
30"
12"
18"
8"
12"
15"
27"
15"
15"
24"
12"
15"
15"
12"
18"
18"
21"
15"
21"
15"
18"
12"
21"
8"
18"
12"
27"
21"
24"
33"
12"
12"
21"
24"
12"
15"
12"
18"
30"
12"
27"
45"
12"
15"
24"
18"
21"
18"
33"
18"
18"
15"
15"
18"
18"
8"
12"
12"
21"
18"
12"
21"
21"
12"15"
54"
Figure ES-9
Modeled Future
Collection System Facilities
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 7\Figure 7-2. Modeled 2040 Collection System Facilities.mxd - jsteiner - 9/2/2022 Modeled Existing Gravity Sewer
Modeled Existing Force Main
Future Gravity Sewer
Future Force Main
[PS
±Existing Pump Station
[PS
±Future Pump Station
Major Developments
General Plan Study Area
Unincorporated Islands
Areas on Septic Tanks to be Sewer
Connected
Additional 2040 Developments
City of Stockton Sphere of Influence
Notes:

1. Facilities constructed during preparation of this Master Plan.

2. This figure does not include improvements identified in Chapter 6.

See Note 1

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Executive Summary
N-129-60-20-42-WP-R-WWMP
ES-23 City of Stockton
Wastewater Master Plan Update
September 2022
Table ES-10. New Pump Station and Force Main Facilities Needed to Serve Buildout Development Name
Development
Area
Peak
Flow, mgd
Force Main
Length, feet
Force Main
Diameter, inches
Peak Flow
Velocity, feet/sec
Gateway Study Area 1 14.88 <10 24 7.3
Mariposa Mariposa Road Community 25.22 36,100(a) 30 8.0 Newton Road CSA-15/Insurance Auto Auction 4.50 2,200 14 6.5 Priest Road South Stockton Commerce
Center/Study Area 16 4.52 2,300 14 6.5
Sanctuary Sanctuary 4.24 <10 14 6.1
System 8 South Stockton Commerce
Center/Study Area 16 15.26 4,300 24 7.5
Tidewater South Stockton
Commerce Center 23.71 2,800 30 7.5
(a) System 7 alignment assumed for a force main from the development area to the RWCF. However, it is recommended. that a shorter force main be constructed in the interim that is directed into the existing trunk sewer along the System 8 pathway.

The Mariposa Road Community development area is predicted to produce a peak flow of 14.0 mgd by 2040 and 23.9 mgd by buildout, based on the planning factors presented in Chapter 4. The model indicates that existing gravity trunk sewers could accommodate these flows for an interim period, especially along the System 8 pathway. However, the model also indicates that insufficient gravity flow capacity exists to accommodate buildout flows from this area. Accordingly, the City will need to decide what infrastructure is needed right away to accommodate the Mariposa Road development area and whether some infrastructural requirements can be delayed. For purposes of master planning, it is recommended that the Mariposa Road development area pump station be constructed to allow for future expansion that can accommodate equipment capable of pumping all flows directly to the RWCF, but that a shorter force main be constructed in the interim that is directed into the existing trunk sewer along the System 8 pathway.

ES.8 RECOMMENDED WASTEWATER COLLECTION SYSTEM CIP
Preliminary planning level cost estimates prepared for this Master Plan are considered Class 5 Estimates in accordance with the guidelines of the Association for the Advancement of Cost Engineering (AACE) International. Construction and capital cost estimates are presented in March 2022 dollars. Construction costs were developed based on a combination of data supplied from manufacturers, historical bids on other wastewater facilities design projects built by other public ag encies, construction costs previously estimated by West Yost, and standard cost estimating guides. Subsequent preliminary and detailed design efforts will serve to refine and confirm the estimates . The estimates have not been adjusted to account for unusual market conditions occurring in 2022 which may dramatically increase the cost of projects constructed in 2022 and potentially in 2023 or later.

Costs developed in this Master Plan include those for traditional gravity sewer construction, trenchless pipe construction, pump stations, and force main piping. In addition, the t otal CIP costs include a design and construction contingency of 35 percent, and a project cost allowance of 45 percent (including 15 percent for engineering, 15 percent for construction management, and 15 percent for implementation). It is assumed that the recommended facilities will be developed in public rights-of-way or on public property; therefore, land acquisition costs have not been included. Construction cost estimates do not include costs for annual O&M nor any allowance for project financing costs.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Executive Summary
N-129-60-20-42-WP-R-WWMP
ES-24 City of Stockton
Wastewater Master Plan Update
September 2022
A recommended CIP list is presented in Table ES-11. The City’s existing CIP list is included as Appendix G.

The major categories shown in Table ES-11 include:
• Pump Station and Force Main Improvements, Existing Conditions (designated as P-#) • Rehabilitation of Existing Gravity Sewer Facilities (designated as R-#) • Capacity Improvements to Existing Gravity Sewer Facilities (designated as C-#) • Future (2040) CIP Facilities (designated as F-#)
• Recommended Studies (designated as S-#)
• Watch List Items (designated as W-#)
• Projects to be Removed from the City’s Existing CIP List (designated as X-#) All of these items except the recommended studies and the projects to be excluded from the City’s existing CIP list are shown schematically in Figure ES-10.

There are 17 items shown for the Pump Station and Force Main Improvements category, all but two of which were identified in the City’s existing CIP list. The most significant items in the list are the 14-Mile Slough PS improvements (Item P-1), the 5-Mile Slough Force Main investigation and improvements (Item P-2), the Lincoln Street PS and Force Main (Item P-3), the Westside Interceptor Parallel Force Main (Item P-4), and the Swenson PS (Item P-5). The remaining items on the list involve inspecting existing pump station components and/or capacities and determining needed improvements. Item P -17 is a general recommendation to rehabilitate and modernize pump stations not otherwise identified in the City’s existing CIP list.

There are 27 items shown for the Rehabilitation of Existing Gravity Sewer Facilities category, all of which were identified in the City’s existing CIP list. Items R-1 through R-10 are considered to be high priority and are recommended for completion within a five -year time frame (2027). Items R -11 through R -24 are considered to be medium priority and are recommended for completion within a ten -year time frame (2032). Items R-25 though R-27 are general rehabilitation categories that are not location-specific.

There are nine items shown for the Capacity Improvements to Existing Gravity Sewer Facilities category, only two of which (Items C-5 and C-9) were identified in the City’s existing CIP list. Items C-1 through C-9 reflect the items shown in Table ES-6 for the Priority 1 Group and the Priority 2 Group. In all cases, it is recommended that the City proceed with surcharge and/or flow monitoring of the lines in question before proceeding with the design of improvements.

There are four items shown for the Recommended Studies category. Items S -1 and S-2 are existing City CIP projects to perform assessments on all pump stations and force main not otherwise identified in the City’s existing CIP list. Additionally, a corrosion and odor control study (S-3) is recommended to assess the effectiveness of existing odor/corrosion control facilities and to identify necessary improvements, and a West Side Interceptor alignment study (S-4) is recommended in advance of Items P-4 above.

There are seven items shown for the Watch List category. Items on this list either show significant surcharging that does not approach outflows under existing conditions, or are modeled as flowing more than 80 percent full and were previously identified in the City’s CIP list. For all of these items, either flow metering or remote level monitoring (e.g., SmartCover® or equivalent) is recommended.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table ES-11. Recomm
ended Capital Improvement Plan
ID Name Descr
iption Justification Time Frame Quantities Actions/Notes Capital Cost, $M City CIP Project Pump Stat
ion and Force Main Improvements, Existing System
P-1 14-Mile
Slough PS Improvements Modify existing pump station to address mechanical equipment failures.

Existing pump station suffers from chronic mechanical failures that warrant modifications to accommodate different pumping
equipment.
2027
(start by
2023)
Pump station modifications
Proceed wi
th design and construction of station
improvement
s to address short-term operational
concerns; conduct evaluation by 2023 to identify long-
term ca
pacity needs

3.60 UW20
022/M20022
P-2 5-Mile Slough Force Main Inspect and rehabilitate or replace existing force main piping Previously identified as needing inspection/rehabilitation 2027
(start
by
2023)
Force main m
odification/
replacement
Proceed with inspection, assessment, and
rehabilitation/ replacement

0.3 (City estimate;
assessment only) M18015
P-3 Lincoln Street PS and Force Main Construct PS and force main; abandon existing siphon; redirect local flow inputs
Existing siphon is over 100 years old and in poor condition; siphon failure would have severe consequences for system operations 2027
(start
by
2023)
~4 mgd pump sta
tion and ~1,800 LF
of force main(a) Update pr
evious design; proceed with construction 8.60 UW24005
P-4 Westside Interceptor Parallel Force Main Construct new parallel force main serving 14-Mile Slough PS and other tributary pump stations
Existing pump force main sizing not adequate for future flow conditions; condition of existing force main unknown
2027
(start
by
2023)
~32,000
LF of 36-inch diameter
parallel force main(a)
Proceed wi
th design and construction of parallel force
main; estimated costs do not include ROW acquisition 51.8 none P-5 Swenson (North) PS Assess pump station components, operation, and capacity
Pump station is not keeping up with incoming flows for both wet and dry weather conditions
2027
(start
by
2023)
TBD Proceed wi
th inspection, assessment, and
rehabilitation/ replacement 2.90 UW24003
P-6 Brookside Estates PS Inspect
and rehabilitate existing pump station
componen
ts Previous
ly identified as needing inspection/rehabilitation 2027 TBD Proceed wi th inspection, assessment, and
rehabil
itation/ replacement 0.90 UW23
003
P-7 College Park (Park View) PS Inspect
and rehabilitate existing pump station
componen
ts Previous
ly identified as needing inspection/rehabilitation 2027 TBD Proceed wi th inspection, assessment, and
rehabil
itation/ replacement 0.80 UW25
003
P-8 Don Avenue & Santiago PS Inspect and rehabilitate existing pump station components; upsize existing PS capacity, as needed
Previously identified as needing inspection/rehabilitation; modeled peak flows exceed station capacity 2027 TBD
Proceed wi
th inspection, assessment, and
rehabil
itation/ replacement; flow or pump runtime
monitoring is recommended to confirm capacity
concerns

0.50 UW13
010/M13010
P-9 Drake & Hwy-99 PS Inspect
and rehabilitate existing pump station
componen
ts Previous
ly identified as needing inspection/rehabilitation 2027 TBD Proceed wi th inspection, assessment, and
rehabil
itation/ replacement 1.30 UW25
005
P-10 Kelley & Mosher PS Inspect
and rehabilitate existing pump station
componen
ts Previous
ly identified as needing inspection/rehabilitation 2027 TBD Proceed wi th inspection, assessment, and
rehabil
itation/ replacement 0.50 UW24
004
P-11 Quail L
akes (Alexandria and 14-Mile
Slough) PS
Inspect
and rehabilitate existing pump station
componen
ts Previous
ly identified as needing inspection/rehabilitation 2027 TBD Proceed wi th inspection, assessment, and
rehabil
itation/ replacement 0.60 UW21
015/M21015
P-12 Thornton & Davis PS Inspect
and rehabilitate existing pump station
componen
ts Previous
ly identified as needing inspection/rehabilitation 2027 TBD Proceed wi th inspection, assessment, and
rehabil
itation/ replacement 0.70 UW13
009/M13009
P-13 Waterloo & Roosevelt PS Inspect and rehabilitate existing pump station components
Previous
ly identified as needing inspection/rehabilitation; pump statio
n is not keeping up with incoming flows for both wet and dry weathe
r conditions
2027 TBD Proceed
with inspection, assessment, and
rehabilitation/ replacement 0.60 UW25004
P-14 Camanche & Ridgeway PS Inspect
and rehabilitate existing pump station
componen
ts
Previous
ly-identified capacity upgrade; no current indication of capaci
ty concerns 2032 -- Assess ph
ysical condition and functionality of pump
statio
n; address any major defects 0.60 UW25
002
P-15 Plymouth & 5 Mile Creek PS Inspect
and rehabilitate existing pump station
componen
ts
Previous
ly-identified capacity upgrade; no current indication of capaci
ty concerns 2032 -- Assess ph
ysical condition and functionality of pump
statio
n; address any major defects 2.40 UW23
001
P-16 Cumberland & 5-Mile Creek PS Assess pump station components, operation, and capacity; upsize existing PS capacity, as needed
Modeled peak flows exceed station capacity; pump station is not keeping up with incoming flows for both wet and dry weather conditions
2032 6.6 mgd pump station
Flow or pump run
time monitoring is recommended to
confirm cap
acity concerns; cost estimate assumes a
new pump station; however, existing station may be
able to acc
ommodate larger pumps

6.0 none
P-17 Pump Stat
ion Rehabilitation and
Modernization
Implement improvements identified under
Recommended Studies Item S-2 below
Aging pump station throughout the City are in need of rehabilitation or replacement
Annual,
ongoing
Structur
al, mechanical, electrical,
control
s, site and security
rehabil
itation and modernization
Adjust annu
al budgeted amount upon completion of
Item S-2 2.0/year none
N-129-60-
20-42-R-WWMP-TABLES Page 1 of 3
City
of Stockton
Wastewater Master Plan Update
Last Revised: 09-01-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table ES-11. Recomm
ended Capital Improvement Plan
ID Name Descr
iption Justification Time Frame Quantities Actions/Notes Capital Cost, $M City CIP Project Rehabilit
ation of Existing Gravity Sewer Facilities
R-1 Church S
treet/Pershing Avenue trunk
sewer
Replace/realign/upsize existing 24-inch diameter VCP
along Church Street and Pershing Avenue from Harrison
Street to Navy Drive
Existing VCP line has adverse slopes, is more than 100 years old, and is in advanced state of deterioration 2027 ~5,600 LF of 30-inch diameter pipe; ~20 MHs
(a)
Finaliz
e existing design; proceed with construction of
identified improvements; should be implemented in
conjunction with Lincoln Street PS project (see above)

8.50 UW17023/M17023
R-2 Mormon Slough trunk sewer
Upsize/re
configure ~2,700 LF of 24-inch diameter pipe;
Jeffers
on Street to Worth Street Identifi
ed by City as needing rehabilitation 2027 TBD Extend des ign of replacement sewer to Worth Street;
proceed
with construction 6.80 UW18
030/M18030
R-3 Navy Drive I-5 trunk sewer CIPP line ~1,700 LF of 54-inch and 42-inch diameter pipe Pipe is in an advanced state of deterioration 2027 Same as existing Design complete; proceed with construction 1.90 M17026 R-4 Navy Drive parallel trunk sewers CIPP line
~8,700 LF of 48-inch, 30-inch, and 24-inch
diameter pi
pe Pipe is in a
n advanced state of deterioration 2027 Same as existing Design complete; proceed with construction 2.80 M15003 R-5 Oak Street trunk sewer Rehabil
itate ~11,000 LF of 24-inch and 21-inch diameter
pipe;
Wilson Way to Pershing Avenue Identifi
ed by City as needing rehabilitation 2027 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 11.70 UW
20016/M20016
R-6 Pershing Avenue sewer Rehabil
itate ~4,300 LF of 24-inch diameter pipe; Oak
Street to Tux
edo Avenue Identifi
ed by City as needing rehabilitation 2027 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 1.50 UW23
008
R-7 Ralph Avenue trunk sewer, Phase 1 Rehabil
itate ~9,200 LF of 30-inch diameter pipe;
Maripos
a Road to B Street Identifi
ed by City as needing rehabilitation 2027 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 1.00 M180
24 R-8 Sierra Neva
da Street trunk sewer CIPP line
~1,100 LF of 36-inch diameter pipe Identifi
ed by City as needing rehabilitation 2027 Same as exis
ting Design compl
ete; proceed with construction 2.10 UW1802
9/M18029
R-9 Union Stre
et sewer Upsize/reconfigure existing 10-inch/ 12-inch diameter line; Harding Way to Oak Street
Line is severely damaged, prone to grease/debris accumulation, and subject to SSOs (per City staff); line is approaching full-pipe capacity 2027 ~4,300 LF of 15-inch diameter pipe; ~10 MHs
(a)
Proceed wi
th design and construction of replacement
sewer 4.3 UW21007/M21007
R-10 Worth Stre
et trunk sewer CIPP line
~8,500 LF of 36-inch diameter pipe Pipe is in a
n advanced state of deterioration 2027 Same as exis
ting Design compl
ete; proceed with construction 4.80 M18028
R-11 Airport Wa
y trunk sewer Rehabil
itate ~5,800 LF of 30-inch diameter pipe; San
Joaqui
n Fairgrounds to Ralph Avenue Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 5.00 UW21
017/M21017
R-12 Alturas Avenue sewer Rehabil
itate ~2,000 LF of 12-inch diameter pipe; Quincy
Street to S
wain Road Identifi
ed by City as needing rehabilitation 2032 TBD Assess ph ysical condition of line; address any major
defects 0.60 UW23
010
R-13 E. Bianchi Street/ Pardee Lane sewer Rehabil
itate ~7,000 LF of 12-inch and 15-inch diameter
pipe;
Quincy Street to Swain Road Identifi
ed by City as needing rehabilitation 2032 TBD Assess ph ysical condition of line; address any major
defects 16.70 UW
24008
R-14 Harding Way sewer Rehabil
itate ~1,600 LF of 12-inch diameter pipe; Wilson
Street to Uni
on Street Identifi
ed by City as needing rehabilitation 2032 TBD Assess ph ysical condition of line; address any major
defects 1.60 UW25
008
R-15 Hazelton Avenue trunk sewer Rehabil
itate ~1,900 LF of 24-inch and 36-inch diameter
pipe;
Della Street to Pilgrim Street Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 2.10 UW24
011
R-16 Lincoln Road trunk sewer Rehabil
itate ~3,000 LF of 36-inch diameter pipe;
Pershing Roa
d to Alexandria Place Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 5.90 UW21
018
R-17 Longview Avenue sewer Rehabil
itate ~3,200 LF of 12-inch diameter pipe; El
Dorado Stree
t to Pacific Avenue Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 1.10 UW23
006
R-18 March Lane trunk sewer Rehabil
itate ~8,400 LF of 24-inch and 30-inch diameter
pipe;
I-5 to Brookside Estates PS Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 6.30 UW25
006
R-19 Ralph Avenue trunk sewer, Phase 2 Rehabil
itate ~2,400 LF of 42-inch diameter pipe; Airport
Way to Perl
man Drive Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 2.50 UW25
012
R-20 Rosemarie Lane sewer Rehabil
itate ~1,400 LF of 12-inch diameter pipe;
Manches
ter Avenue to Crown Avenue Identifi
ed by City as needing rehabilitation 2032 TBD Assess ph ysical condition of line; address any major
defects 1.60 UW23
014
R-21 Ryde Avenue trunk sewer Rehabil
itate ~1,400 LF of 30-inch and 36-inch diameter
pipe;
River Drive to De Ovan Avenue Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 3.40 UW25
009
R-22 Sperry Road/Gibraltar Court sewer Rehabil
itate ~6,200 LF of 24-inch and 27-inch diameter
pipe;
Airport Way to Industrial Drive Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 4.60 UW23
009
R-23 Tuxedo Avenue sewer Rehabil
itate ~1,900 LF of 16-inch diameter pipe;
Kensington
Way to Orange Street Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th assessment of existing pipes and design
of improvemen
ts 0.50 UW23
007
R-24 Backyard and smaller diameter sewers Replace 6-in
ch diameter sewers near Scribner/ 7th/
Howard/
Pilgrim Streets Identifi
ed by City as needing rehabilitation 2032 TBD Proceed wi th design and construction of replacement
sewer 1.9 vari
ous
R-25 Sewer Maint
enance Hole Rehab Existi
ng City CIP line item Identifi
ed by City as needing rehabilitation Ongoing TBD As needed 2.10 UW2001 1/M20011
R-26 Sanitar
y Sewer Small Diameter Lines
Replacemen
t Existi
ng City CIP line item Identified by City as needing rehabilitation Ongoing TBD As needed 1.80 UW21016/M21016 R-27 Sanitar
y Sewer Large Diameter Lines
Replacemen
t Existi
ng City CIP line item Identified by City as needing rehabilitation Ongoing TBD As needed 4.50 UW20020/M20020 N-129-60-
20-42-R-WWMP-TABLES Page 2 of 3
City
of Stockton
Wastewater Master Plan Update
Last Revised: 09-01-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table ES-11. Recomm
ended Capital Improvement Plan
ID Name Descr
iption Justification Time Frame Quantities Actions/Notes Capital Cost, $M City CIP Project Capacity Impr
ovements to Existing Gravity Sewer Facilities
C-1 E. Marsh
Street sewer Upsize existing 18-inch diameter sewer Existing conditions model shows potential for severe surcharging and/or SSOs 2035 ~7,400 LF of 2
4-inch diameter pipe;
22 MHs(a) Monitor wi
th level sensor and/or flow meter 11.8 none
C-2 El Dorado Street /
S. Center Street sewer
Upsize existing 16-inch, 18-inch and 24-inch diameter
sewers
Existing conditions model shows potential for severe surcharging and/or SSOs 2035
~2,800 LF of 2
4-inch diameter pipe;
10 MHs(a) Monitor wi
th level sensor and/or flow meter 4.5 none
C-3 S. Wilson Way sewer Upsize existing 10-inch and 12-inch diameter sewers Existi ng conditions model shows potential for severe surcharging and/or S
SOs 2035 ~1,000 LF of 2
1-inch diameter pipe;
6 MHs Monitor wi
th level sensor and/or flow meter 1.5 none
C-4 E. 6th Street Upsize existing 12-inch diameter sewer Existing conditions model shows potential for severe surcharging and/or SSOs 2035
~700 LF of 18
-inch diameter pipe;
5 MHs(a) Monitor wi
th level sensor and/or flow meter 0.9 none
C-5 E. Main Street sewer Upsize existing 12-inch and 16-inch diameter sewers Existing conditions model shows potential for excessive surcharging 2035 ~8,700 LF of 1 8-inch diameter pipe;
~30 MHs(a) Monitor wi
th level sensor and/or flow meter 10.7 none
C-6 W. Washington Street / Port Road 23
sewer
Upsize existing 12-inch, 15-inch and 18-inch diameter
sewers Existing conditions model shows potential for excessive surcharging 2035 ~3,800 LF of 2
1-inch diameter pipe;
10 MHs(a) Monitor wi
th level sensor and/or flow meter 5.3 none
C-7 Don Avenue / Meadow Avenue sewer Upsize existing 12-inch and 16-inch diameter sewers Existing conditions model shows potential for excessive surcharging 2035 ~2,200 LF of 1
5-inch diameter pipe;
2,200 LF of 2
1-inch diameter pipe;
18 MHs(a)
Monitor wi
th level sensor and/or flow meter 5.5 none
C-8 S. El Dorado Street sewer Upsize existing 12-inch diameter sewer Existing conditions model shows potential for excessive surcharging 2035 ~1,800 LF of 1 5-inch diameter pipe;
6 MHs(a) Monitor wi
th level sensor and/or flow meter 1.9 none
C-9 Del Norte Street sewer Upsize existing 36-inch diameter sewer Existing conditions model shows potential for excessive surcharging 2035 ~4,100 LF of 4 2-inch diameter pipe;
~20 MHs(a) Monitor wi
th level sensor and/or flow meter 11.4 UW25010
Recommende
d Studies
S-1 Asset Condit
ion Assessment for Sanitary
Sewer Force Mains Existing City CIP line item
Pump statio
ns not listed above may have deficiencies; assessments
are warr
anted; power management technologies may reduce
operati
ng costs
2027 TBD Unde
rtake a program to prioritize and assess all City
pump stations

1.1 (City estimate) UW20018/M20018
S-2 Asset Condition Assessment for Sanitary
Sewer Pump Stations Existing City CIP line item
Force mains no
t listed above may have deficiencies; assessments are
warran
ted; power management technologies may reduce operating costs
2027 TBD Unde
rtake a program to prioritize and assess all City
pump station force mains

0.5 (City estimate) UW20019/M20019
S-3 Corrosion and Odor Control Study
Evaluat
e existing and potential future odor control and
corrosio
n control options, including innovative
technol
ogies where appropriate
Effectiv
eness of existing odor/corrosion control facilities should be periodically reassessed for effectiveness 2027 TBD Perform the study to identify needs and confirm current operations 0.3 none
S-4 West Side Interceptor Alignment Study
Identify
and evaluate alternative alignments and costs
for paral
lel force main from 14-Mile Slough PS to the
RWCF
An alignment s
tudy is needed in advance of force main design 2027 TBD Perform the alignment study to confirm project costs and provide a basis for design 0.5 none
Watch Li
st Items, Existing Conditions
W-1 Hammer Lane
trunk sewer UPRR to Pershing Avenue Existi
ng conditions model shows pipe flowing >80% of gravity
capaci
ty; past SSOs at UPRR undercrossing -- TBD Monitor thi
s line with level sensor and/or flow meter -- none
W-2 Market Street sewer El Dorado Street to Lincoln Street Existing conditions model shows potential for significant surcharging -- TBD Monitor with level sensor and/or flow meter 3.40 M18014 W-3 N. Lincoln Street sewer Upstream terminus to N. Lincoln Street Existing conditions model shows potential for significant surcharging -- TBD Monitor with level sensor and/or flow meter -- none W-4 Ponce De Leon
to Etna Street backyard
sewer Ponce De Leon
Avenue to Etna Street Existi
ng conditions model shows pipe flowing >80% of gravity
capaci
ty -- TBD Monitor thi
s line with level sensor and/or flow meter 1.50 UW23013 W-5 Scotts Avenue trunk sewer Pershing Avenue to Navy Drive Existi ng conditions model shows pipe flowing >80% of gravity
capaci
ty -- TBD Monitor wi
th level sensor and/or flow meter 0.30 UW24009
W-6 Thornton Road sewer MacDuff Avenue to Hammer Lane Existi ng conditions model shows pipe flowing >80% of gravity
capaci
ty -- TBD Monitor wi
th level sensor and/or flow meter 4.00 UW25011
W-7 Waterloo Road sewer Williams Street to Hiawatha Avenue Existing conditions model shows potential for significant surcharging -- TBD Monitor with level sensor and/or flow meter -- none Projects to b
e Excluded from Existing CIP (pending condition assessments) X-1 N. El Dora
do Street sewer E. Sonoma Avenue to E. Wyandotte Street Identifi ed in the 2008 Wastewater Master Plan; current modeling shows no
current or future capacity issues -- -- Assess ph
ysical condition of line; address any major
defects 1.30 UW23
011
X-2 N. El Dorado Street sewer E. Main Street to E. Oak Street Identifi ed in the 2008 Wastewater Master Plan; current modeling shows no
current or future capacity issues -- -- Assess ph
ysical condition of line; address any major
defects 2.50 UW2301
2;
UW2401
0 X-3 Pershing Avenu
e trunk sewer Meadow Avenue to W. Lincoln Road Identifi ed in the 2008 Wastewater Master Plan; current modeling shows no
current or future capacity issues -- -- Assess ph
ysical condition of line; address any major
defects 3.30 UW22
003
X-4 Wyandotte Street sewer California Street to Pacific Avenue Identifi ed in the 2008 Wastewater Master Plan; current modeling shows no
current or future capacity issues -- -- Assess ph
ysical condition of line; address any major
defects 3.50 UW25
007
(a) Sizing ba
sed on buildout model results.

N-129-60-
20-42-R-WWMP-TABLES Page 3 of 3
City
of Stockton
Wastewater Master Plan Update
Last Revised: 09-01-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Figure ES-10
Collection System CIP Projects
and Other Future Facilities
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 8\Figure 8-1. Proposed Collection System CIP Projects.mxd - jsteiner - 9/2/2022

TF C W RU
[PS
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§¨¦5
ÄÆ4
ÄÆ99
C-1
C-2
C-3
C-4
C-5
C-6
C-8
W-2
W-7
C-7
W-5
C-9
R-21
R-17
W-6
R-16
R-4
R-10
R-3
R-8R-1
R-5
R-7
R-6
R-2
R-18
R-22
R-11
R-19
R-9
R-23
R-15
W-4
W-1
Gateway
PS
Sanctuary
PS
Newton
Road PS
Mariposa
PS
System 8
PSTidewater
PS
Priest
Road PS
W-3
R-12
R-13
R-14
R-20
See Note 1

A R C H

A I R P O R T R D

M O R A D A L N

F R E M O N TS T

M A I N
S T

E I G H T M I L E R D

C H A R T E R W A Y

C A L I F O R N I A
S T

F I L B E R T S T

P E R S H I N G A V E

M A R I P O S A
R D

C E N T E R S T

D A V I S R D
P O R T1 3 R D

F A R M I N G T O NR D

A L P I N E A V E

H O W A R DR D

P A C I F I C A V E

E L D O R A D O S T

B E N J A M I N

H O L T D R

S P E R R Y R D

S I E R R A

N E V A D A S T

A I R P O R T W A Y

O A K S T

H A Z E L T O NA V E

P A R K S T

B U C K L E Y

C O V E W A Y

H O L M A N R D

H A M M E R L N

A L P I N E A V E

E L D O R A D O S T

C O U N T R Y

C L U B B L V D

F R E N C H C A M P R D

L O W E R

S A C R A M E N T O R D

W I L S O N W A Y

M A R C H L N

T H O R N T O N R D

N A V Y D R

C H E R O K E E R D

M A R I P O S A R D

M A N T H E Y
R D

R O T H R D

A R C H R D

W A T E R L O O R D

W E S T L N

P O R T O F

S T O C K T O N E Y

H A R L A N R D
24"
15"
18"
15"
18"
15"
12"
24"
18"
27"
27"
30"
15"
12"
27"
8"
12"
15"
12"
12"
15"
21"
15"
42"
36"
12"
36"
21"
12"
18"
24"
15"
18"
15"
12"
24"
30"
36"
12"
18"
12"
15"
15"
24"
12"
15"
30"
12"
18"
8"
12"
15"
27"
15"
24"
15"
12"
18"
15"
12"
18"
21"
15"
21"
18"
12"
21"
8"
18"
12"
27"
21"
24"
24"
33"
12"
12"
21"
24"
12"
15"
30"
12"
27"
45"
12"
15"
24"
18"
21"
18"
33"
18"
18"
15"
15"
18"
18"
8"
12"
21"
18"
12"
21"
18"
21"
12"15"
54"
Existing Gravity Sewer
Existing Gravity Sewer Identified for Rehab
Gravity Sewer Capacity Deficiency
Watch List
Future Gravity Sewer
Existing Force Main
Existing Force Main Identified for Rehab
Future Force Main
[PS
± Existing Pump Station
[PS
± Pump Station Identified for Improvements
[PS
± Future Pump Station
TF C W RU Regional Wastewater Control Facility
Major Developments
General Plan Study Area
Unincorporated Islands
Additional 2040 Flow Contributing Areas
City of Stockton Sphere of Influence
Notes:

1. Facilities constructed during preparation of this Master Plan.

2. Items R-24 through R-27 not shown; see Figure 6-3.
0 1.250.625
Miles

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Executive Summary
N-129-60-20-42-WP-R-WWMP
ES-29 City of Stockton
Wastewater Master Plan Update
September 2022
Finally, there are four items shown for the Projects to be Excluded from the City’s Existing CIP List category.

These items were identified in previous planning as requiring upsizing to accommodate existing or future development conditions. However, due to updated information obtained and modeling performed for this Master Plan, none of the facilities in question appear to be approaching capacity within the time frame of identified 2040 development and , therefore, should not be included in the CIP for capacity reasons. However, if one or more of these facilities are found to be in an advanced state of deterioration, those facilities should remain on the City’s CIP list for rehabilitation.

Appendix H provides an analysis of how the conclusions of this Master Plan affect the current rate and connection fees. The most recent rate study was adopted in 2019 and included a capital project list , as well as O&M costs for the wastewater utility. The analysis presented in Appendix H does not replace the adopted rate study, but rather assesses whether the conclusions of the 2019 Rate Study remain valid and whether the planned annual rate increases continue to be supported by anticipated costs. The analysis presented in Appendix H indicates that annual rate increases, consistent with the most recently adopted rate study, will be sufficient to fund the recommended CIP presented in this Master Plan while meeting the other revenue requirements for the wastewater utility. While connection fees may be appropriately used to fund a portion of some improvements needed to serve grow th throughout the City, is assumed, for the purposes of the financial review , that connection fee reserves will not be used to meet the predicted revenue requirements of the utility. A review and update of connection fees is being conducted under a separate, ongoing process.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
1-1 City of Stockton
Wastewater Master Plan Update
September 2022
CHAPTER 1
Introduction
The purpose of this Wastewater Master Plan Update (Master Plan) for the City of Stockton (City) is to evaluate the existing wastewater collection system infrastructure, to address potential impacts of near- term and long-term planned growth, and to develop a comprehensive road map for the City’s wastewater system capital improvement program. The City’s Municipal Utilities Department operates the City’s wastewater collection and treatment systems, which serve customers throughout the City and some outlying areas immediately to the east and south of the City limits. This Master Plan addresses the existing and planned wastewater service areas. The key topics covered in this chapter include:
• Need for the Project
• Master Plan Objectives and Priorities
• Previous and Ongoing Studies
• Report Organization
• Acknowledgements

1.1 NEED FOR THE PROJECT
The City completed its most recent wastewater facilities master plan in 2008. Since that time, the City has completed its Envision Stockton 2040 General Plan (General Plan), which provides an updated framework for future development in the City through 2040. In addition, the severe drought conditions that occurred during the period of 2013 through 2016 led to State-mandated water conservation practices, coupled with new legislation establishing statewide water efficiency standards , which have resulted in reduced per - capita wastewater generation rates.

All of the se factors have created a need to reassess the City’s wastewater collection capacity and treatment infrastructure needs to support the planning and funding of safe and reliable wastewater facilities serving existing and future residents and businesses.

1.2 MASTER PLAN OBJECTIVES AND PRIORITIES
The primary objectives of this Master Plan are to:
• Evaluate historical and existing wastewater flows to understand recent patterns and trends, and develop future collection system flow projections for General Plan buildout conditions. • Review and refine performance and planning criteria under which the wastewater system will be evaluated and recommendations for future facilities will be formulated. • Update and calibrate the City’s wastewater collection system hydraulic model to provide an accurate tool for evaluating various collection system development scenarios. • Evaluate the need for new wastewater collection system facilities (including pipelines and pumping facilities) to meet existing, near-term, and buildout needs. • Update and prioritize the City’s capital improvement program for wastewater collection system improvements.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 1
Introduction
N-129-60-20-42-WP-R-WWMP
1-2 City of Stockton
Wastewater Master Plan Update
September 2022
This Master Plan has been prepared to be consistent with the mission of the City’s Municipal Utilities Department:

The City of Stockton Municipal Utilities Department’s mission is to provide high- quality drinking water on demand; collect, treat, and dispose of wastewater; and collect and dispose of stormwater, all in accordance with applicable regulations and responsible business practices.

Key priorities for this Master Plan include the following:
• Clearly define long-term wastewater system needs so that collection system infrastructure is properly sized
• Develop an updated hydraulic model that:
— Accurately represents the wastewater collection system — Identifies existing capacity deficiencies
— Simulates current flows within pipelines scheduled for rehabilitation — Allows for accurate assessment of needed infrastructure to serve proposed future development projects, which can be easily updated to evaluate future changes • Develop an updated Capital Improvement Plan (CIP) to provide a basis for future wastewater rates and connection fees based on current wastewater capacity needs (confirmed through field measurements) and projected future wastewater flows based on proposed development
• Identify applicable regulatory requirements and develop strategies for ongoing compliance with those requirements
• Plan for future extensions of service to areas currently served by onsite treatment and disposal (septic tanks) within the planning boundary
• Produce a Master Plan report that will serve as a user-friendly reference tool both for City staff and for developers

1.3 PREVIOUS AND ONGOING STUDIES
Studies relevant to this Master Plan that have been completed include:
• Wastewater Master Plan, 2008
• City of Stockton Gravity Sanitary Sewer Collection System Asset Management and Master Plan, 2018
• Regional Wastewater Control Facility (RWCF) Capital Improvement and Energy Management Plan, 2011
• RWCF Modifications Project Basis of Design Report, 2019 • Envision Stockton 2040 General Plan, 2018
• Wastewater Cost of Service Rate Study, 2019
• Water Master Plan Update, 2021
Each of these studies is described briefly below.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 1
Introduction
N-129-60-20-42-WP-R-WWMP
1-3 City of Stockton
Wastewater Master Plan Update
September 2022

1.3.1 Wastewater Master Plan, 2008
The City’s previous Wastewater Master Plan was completed in 2008 to support future development in accordance with the City’s 2035 General Plan. The 2008 Wastewater Master Plan addressed the following:
• Likely collection system capacity constraints under existing and future flow conditions • The need for additional trunk sewers and pump stations to serve areas of future growth • The need for documentation of wastewater treatment facility needs and potential future regulatory changes triggering additional improvements
• The need to implement a planned capital improvement program with significant funding to accommodate growth
As noted above, the current Master Plan is a comprehensive update that will be based on extensive flow monitoring data and the results of field investigations that were not available for the 2008 evaluation.

1.3.2 City of Stockton Gravity Sanitary Sewer Collection System Asset Management and Master Plan, 2018
In 2018, HDR Engineering evaluated comprehensive closed-circuit television (CCTV) inspection records for nearly all collection system gravity pipelines , and subsequently prepared the Gravity Sanitary Sewer Collection System Asset Management and Master Plan report. The report provides a prioritized CIP to rehabilitate gravity sewers that have deteriorated due to age and environmental conditions.

1.3.3 RWCF Capital Improvement and Energy Management Plan, 2011 The Capital Improvement and Energy Management Plan ( CIEMP), which was completed in August 2011, was a planning-level document identifying a series of improvements needed at the City’s RWCF where all wastewater generated within the City’s wastewater service area is treate d. The CIEMP focused on rehabilitating or replacing major portions of the aging RWCF, and adding or modifying processes to achieve regulatory compliance. The CIEMP considered wind and solar energy production at the RWCF and concluded that the most cost -effective option to reduce outside energy dependence at the plant is to enhance the existing cogeneration system and increase biogas production. When the City began implementation of the CIEMP by initiating design of a new headworks facility, unexpected high costs were estimated for that project, which led to the conclusion that a more detailed evaluation and modified approach to rehabilitating the RWCF was necessary.

1.3.4 RWCF Modifications Project Basis of Design Report, 2019 To control short -term and long-term costs, the City entered into a progressive design -build contract in 2016 to design and construct comprehensive preliminary, primary, secondary , and tertiary treatment system improvements at the RWCF. The initial engineering work for the project was compl eted in 2018 and resulted in a revised approach to achieving infrastructure rehabilitation and regulatory compliance at the RWCF. The results of this detailed analysis are documented in the Basis of Design Report dated January 3, 2019. Detailed design and construction of the improvements began in 2019 and are expected to be completed in 2023. A portion of the work will add treatment facilities to remove nitrogen from the effluent in order to meet the 2024 regulatory deadline. The project will modernize a sub stantial portion of the RWCF, thus reducing operating and maintenance costs associated with the existing facilities that are reaching the end of their useful life. Upgrades and capacity improvements to the RWCF are not addressed further in this Master Plan.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 1
Introduction
N-129-60-20-42-WP-R-WWMP
1-4 City of Stockton
Wastewater Master Plan Update
September 2022

1.3.5 Envision Stockton 2040 General Plan, 2018
The Envision Stockton 2040 General Plan (General Plan) was adopted in December 2018. The General Plan process included a comprehensive evaluation of the City’s planning boundaries, including the City’s Sphere of Influence (SOI).

A key objective of the General Plan was the establishment of a strategy for urban growth that reflected the community’s vision and supported the City’s Climate Action Plan. This objective was achieved through extensive community outreach and engagement, resulting in a land use plan that emphasizes infill development in the City’s core and supports employment and economic development City-wide.

Key achievements of the General Plan are summarized as follows:

Increased allowable residential densities and intensity of development downtown and in the greater downtown area, as compared to the previous General Plan. Policies encouraging infill are prevalent, particularly for downtown and South Stockton.

Reduced by almost 8,000 acres (12 square miles) the amount of agricultural land that could be converted to urban land uses, as compared to the previous General Plan.

Featured a new policy to create an agricultural belt between Stockton and Lodi in collaboration with Lodi, San Joaquin County, and local property owners.

Provided guidance for reevaluating the City’s public infrastructure, such as roadways and water and sewer distribution systems, which will help the City to determine whether infrastructural capital and maintenance costs can be supported by development projects.

Through the 2040 General Plan Update process, the City evaluated infrastructure capacity in light of land use alternatives considered, and developed recommendations for updating backbone infrastructure plans to reflect the adopted land use plan. The 2040 General Plan Update also included the preparation of an Infrastructure Financing Strategy to address the identified infrastructure needs.

The City is committed to protecting water quality by e nsuring adequate collection, treatment, and safe disposal of wastewater. The City is also committed to limiting or reducing per capita wastewater generation rates through water use conservation and reduction measures . General Plan goals, policies , and actions with potential relevance to wastewater service within the City include the following:
• Require water and energy conservation and efficiency in both new construction and retrofits.
• Carefully plan for future development and proactively mitigate potential impacts. • Ensure that all neighborhoods have access to well-maintained public facilities and utilities that meet community service needs.
• Require new development to install non-potable water infrastructure for irrigation of large, landscaped areas where feasible.
• Investigate and implement code amendments to allow installation of dual plumbing and/or rainwater capture systems to enable use of recycled water and/or captured rainwater generated on-site.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 1
Introduction
N-129-60-20-42-WP-R-WWMP
1-5 City of Stockton
Wastewater Master Plan Update
September 2022

1.3.6 Wastewater Cost of Service Rate Study, 2019
The City prepared a Wastewater Cost of Service Rate Study and adopted a five-year rate plan in 2019. The study r eviewed and analyze d updated cost information from administration, collection, treatment , maintenance, capital project s, and debt service coverage. This Master Plan provide s a list of recommended wastewater system improvements that may be used to confirm the basis of the Rate Study.

The recommended wastewater system improvements address both existing and future system needs .

System improvements needed to meet existing system deficiencies are allocated to existing users and are to be funded through rates. System improvements needed to expand the collection and treatment systems to serve future planned development are allocated to future users and are to be funded through wastewater service connection fees.

1.3.7 Water Master Plan Update, 2021
A recent update to the City’s Water Master Plan was also prepared by West Yost and was adopted by City Council on February 23, 2021. Where applicable, the data and assumptions used in this Master Plan have conformed with those of the Water Master Plan Update to ensure that the two plans are consistent in their assumptions, projections, and recommendations. In particular, it is important to ensure that land use assumptions are consistent between the two reports, and that water demand projections and wastewater flow projections are consistent so that both facilities within systems are appropriately sized.

1.4 REPORT ORGANIZATION
This Master Plan is organized into the following chapters:
• Chapter 1. Introduction
• Chapter 2. Existing Wastewater Collection System
• Chapter 3. Existing Wastewater Flows
• Chapter 4. Collection System Planning, Design, and Performance Criteria • Chapter 5. Hydraulic Model Development
• Chapter 6. Analysis of Existing Flow Conditions
• Chapter 7. Analysis of Future Flow Conditions
• Chapter 8. Recommended Wastewater Collection System CIP The following appendices to this Master Pla n contain additional technical information, assumptions , and calculations:
• Appendix A. Collection System Flow Metering Locations • Appendix B. Collection System Flow Split Locations
• Appendix C. Flow Split Survey Notes
• Appendix D. Modeled vs. Metered Dry Weather Diurnal Flows • Appendix E. Modeled vs. Metered Wet Weather Flows
• Appendix F. Modeled vs. Metered Wet Weather Flow Depths • Appendix G. Existing City Wastewater Facilities CIP
• Appendix H. Wastewater Systems Financial Analysis

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 1
Introduction
N-129-60-20-42-WP-R-WWMP
1-6 City of Stockton
Wastewater Master Plan Update
September 2022

1.5 ACKNOWLEDGEMENTS
This Master Plan was made possible by the focused involvement and assistance of City staff. In particular, the following staff provided comprehensive information, significant input , and important insights throughout development of this Master Plan:
• Mel Lytle, Director, Municipal Utilities Department
• John Abrew, former Director, Municipal Utilities Department • Deedee Antypas, Deputy Director, Wastewater Division
• Gemma Biscocho, Senior Civil Engineer, Engineering Division • Stephen Kenning, former Assistant Municipal Utilities Department Director • Ali Gharegozloo, Engineering Services Manager, Engineering Division • Ann Okubo, Senior Civil Engineer, Engineering Division • Jeff Marasovich, Deputy Director, Collections Division • Mario Caballero, former Program Manager III, Collections Division • Matt Diaz, Planning Manager, Community Development Department • Eric Johnson, Senior Plant Maintenance Supervisor
• Ernesto Lopez, Junior Engineer, Engineering Division
• Michael McDowell, Deputy Director, Planning & Engineering, CDD • Nicole Moore, Senior Planner, Community Development Department • Dagmara Saini, Program Manager III, Collections Division

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
2-1 City of Stockton
Wastewater Master Plan Update
September 2022
CHAPTER 2
Existing Wastewater Collection System
This chapter describes the City’s existing wastewater collection system, which is managed by the City of Stockton Municipal Utility Department. The wastewater collection system information presented in this chapter is based on a review of previous studies, design reports, maps, plans, ope rating records, geographic information system (GIS) data, and discussions with City staff. The following topics are addressed in this chapter:
• Existing Service Area
• Existing Collection System Facilities

2.1 EXISTING SERVICE AREA
Key topics discussed in this section include:
• Service Area Description
• Service Connections and Customers

2.1.1 Service Area Description
The City of Stockton is the county seat and the largest city in San Joaquin County. According to the California Department of Finance, the population of the City in January 2021 was estimated to be 320,876.

The City experienced significant growth (approximately 2.3 percent per year) from 2000 to 2008 , and more moderate growth (approximately 0.8 percent) since 2008. The existing City limits encompass an area of 41,777 acres, or approximately 65 square miles.

The existing wastewater collection system service area includes residential, commercial, industrial, municipal, and mixed -use areas within the City , as well as surrounding and embedded urbanized but unincorporated county areas that are represented by the following five satellite agencies:
• Country Club Sanitary Maintenance District
• San Joaquin County Maintenance Division
• Port of Stockton
• Northern California Youth Correctional Center
• California Health Care Facility
The City’s collection system can be separated into 10 existing sub-areas or “systems”. Systems 1 through 7 have been in existence for at least 25 years and encompass most of the City. System 8 serves southern portions of the City and is currently partially developed. System 9 serves the eastern edge of the City along Highway 99, and most of this system is either undeveloped or developed but not connected; however, the backbone trunk sewer and two pump stations for System 9 were completed in 2007. System 10 serves northern portions of the City and is currently partially developed. Four additional systems, designated as Systems 12 through 15, are undeveloped and were previously identified as areas of long-term future growth; however, those areas are no longer planned for significant development based on the recent General Plan update. The total acreages for Systems 1 through 10, including developed and undeveloped portions, are summarized in Table 2-1.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 2
Existing Wastewater Collection System
N-129-60-20-42-WP-R-WWMP
2-2 City of Stockton
Wastewater Master Plan Update
September 2022
Table 2-1. Collection System Tributary Areas
System
Tributary area, acres
Total Developed Undeveloped
1 2,037 2,037 0
2 9,420 9,420 0
3 6,516 6,516 0
4 2,222 2,222 0
5 3,620 3,620 0
6 5,060 3,786 1,274
7 5,351 4,781 570
8 11,500 7,312 4,188
9 2,312 1,272 1,040
10 9,224 5,174 4,050
TOTAL 57,262 46,140 11,122
There are 17 areas that are partially or fully enclosed by the Stockton City limits boundary and are referred to here as unincorporated islands. The islands are partially or fully-developed areas that were never annexed into the City, and are therefore not under City jurisdiction. The water sources for these areas include the City, California Water Service (CalWater), or private wells. Some portions of the unincorporated islands are connected to the City’s wastewater collection system, with the remainder served by onsite treatment (septic tanks and leach fields). Some of the areas are under the jurisdiction of a San Joaquin County Maintenance District. Table 2-2 presents a summary of these unincorporated islands and indicates which of the unincorporated islands are currently connected to the City’s wastewater collection system and which are served by septic tanks and leach field systems.

The City’s wastewater collection system conveys all flows to the RWCF, which is located along the San Joaquin River on the south side of Navy Drive on the western edge of the City. All existing and planned development areas and the unincorporated islands are expected to be served by the RWCF under buildout development conditions, regardless of water source, as a prudent planning assumption for the purposes of the Master Plan; however, this assumption should not be construed to be a commitment or agreement to serve any particular area.

Figure 2-1 shows t he existing collection system service areas, City limits, Sphere of Influence, and unincorporated islands. Figure 2-2 shows all 12-inch diameter and larger sewer lines, the locations of all public sanitary sewer pump stations, and the location of the RWCF.

2.1.2 Service Connections and Customers
A summary of land use and parcel information, developed as part of the 2018 General Plan process, is presented in Table 2-3. The results are limited to parcels within Systems 1 through 10, and are presented both in terms of total parcels and parcels with non -zero water demands, the latter of which provides a rough indicator of parcel occupancy.

ATTACHMENT C
DRAFT
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Table 2-2
. Summary Information for Stockton Unincorporated Islands LAFCO Are
a Area, acres Population Sanitary System Sewer Pipes in GIS? Potable Water System Water Meters in GIS? Stockton Northeast 48.30 161 Septic Tanks No Unknown No Elkhorn 131.46 251 Septic Tanks No Master Meter No
Rancho San Joaquin 45.79 163 Septic Tanks No Master Meter No Wagner Heights 68.19 222 Septic Tanks No Unknown Yes, City(a) Colonial Heig
hts 227.47 City Connection Yes Master Meter No
Lincoln Village 460.46 City Connection Yes Master Meter No Oakridge-Swenson Park 102.15 Septic Tanks No Private Wells Yes, City(a) West I-5 6

4.10 347 City Connection Yes Master Meter No
Weber Grant 21.99 21 Septic Tanks No Individual Meters Yes, Cal Water Sperry Tract 4.16 36 Septic Tanks Yes Individual Meters Yes, Cal Water West Lane 46.58 488 City Connection Yes Individual Meters Yes, Cal Water North Oaks 51.73 653 City Connection Yes Individual Meters Yes, Cal Water Rose Terrace 32.82 254 City Connection Yes Individual Meters Yes, Cal Water Country Club 1320.80 9,226 City Connection Yes Individual Meters Yes, Cal Water Boggs Tract 96.91 229 City Connection Yes Individual Meters Yes, Cal Water Mosswood Park 297.11 1,200 City Connection Yes Individual Meters Yes, Cal Water El Dorado/Airport 241.91 0 none indicated No None Yes, Cal Water(a) (a) Part
ial information only.
6,51
6 N-129-60-20
-42-WP-R-WWMP
City of Stockton
Wa
stewater Master Plan Update
Last Revised: 06-10-2022

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Figure 2-1
Collection System Service Areas
and Unincorporated Islands
City of Stockton
Wastewater Master Plan Update
Collection System Service Areas
Unincorporated Islands
City of Stockton Limits
City of Stockton Sphere of Influence
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 2\Figure 2-1. Collection System Service Areas and Unincorporated Islands.mxd - jsteiner - 6/15/2022 1-10
Notes:

1. 2018 aerial imagery obtained from the USDA Farm Service Agency.

2. City limits based on GIS shapefile obtained from San Joaquin County website.

3. Unincorporated Island boundaries sourced from the City of Stockton Sphere of Influence Municipal Service Review, prepared by PlaceWorks on April 23, 2020.

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WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 2\Figure 2-2. Existing Wastewater Collection System.mxd - jsteiner - 6/15/2022 C o l l e c t io n S y s t e m S e r vic e A r e a s C it y o f S t o c k t o n S ph e r e o f I nf l u e nc e

TF C W R
U R e g io na l Wa s t e w a t e r C o nt r o l F a c il it y [PS
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1-10
Figure 2-2
Existing Wastewater
Collection System
City of Stockton
Wastewater Master Plan Update
C it y o f S t o c k t o n L im it s

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 2-3. Ci
ty of Stockton Land Use and Parcel Information for Systems 1 through 10 Land Use
Parcel
Count
Area,
acres
Average Parc
el
Size, acres
Portion of
Total Count
Portion of
Total Area
Parcel
Count
Area,
acres
Portion of Tot
al
Non-Zero
Demand Count
Portion of Tot
al
Non-Zero
Demand Area
Percentage of
Parcels Occupi
ed
(By Count)(a)
Percentage of
Parcels Occupi
ed
(By Area)(a)
Resident
ial 90,406 23,143 0.26 89.93% 41.49% 78,639 14,738 94.31% 55.13% 86.98% 63.68% High Density Residential 3,238 971 0.30 3.22% 1.74% 1,437 630 1.72% 2.35% 44.38% 64.86% Low Density Residential 79,474 19,892 0.25 79.06% 35.66% 70,829 12,898 84.95% 48.25% 89.12% 64.84% Medium Density Residential 7,534 1,893 0.25 7.49% 3.39% 6,373 1,210 7.64% 4.53% 84.59% 63.94% Residential Estate 160 388 2.42 0.16% 0.70% 0 0.0 0% 0% 0% 0% Commercial/Industrial/Institutional 7,738 20,727 2.68 7.70% 37.16% 3,885 7,742 4.66% 28.96% 50.21% 37.35% Administrative Professional 874 487 0.56 0.87% 0.87% 314 335 0.38% 1.25% 35.93% 68.77% Commercial 4,123 3,612 0.88 4.10% 6.48% 2,369 1,970 2.84% 7.37% 57.46% 54.55% Industrial 2,184 9,705 4.44 2.17% 17.40% 810 3,307 0.97% 12.37% 37.09% 34.08% Institutional 143 5,627 39.35 0.14% 10.09% 42 1,853 0.05% 6.93% 29.37% 32.93% Mixed Use 414 1,296 3.13 0.41% 2.32% 350 277 0.42% 1.04% 84.54% 21.36% Other 2,381 11,906 5.00 2.37% 21.35% 857 4,254 1.03% 15.91% 35.99% 35.73% Open Space/Agriculture 50 626 12.53 0.05% 1.12% 1 7.0 0.00% 0.03% 2.00% 1.12% Parks and Recreation 147 1,575 10.71 0.15% 2.82% 46 940 0.06% 3.51% 31.29% 59.65% Not specified 2,184 9,705 4.44 2.17% 17.40% 810 3,307 0.97% 12.37% 37.09% 34.08% TOTAL 100,525 55,777 0.55 100% 100% 83,381 26,733 100% 100% 82.95% 47.93% (a) As an approximation, it is
assumed that all developed and occupied parcels have non-zero water demands.

All Parcels Parcel
s w/Non-Zero Water Demands
N-129-60-20
-42-WP-R-WWMP
City of Stockton
Wastewater Master Pla
n Update
Last Revised: 02
-15-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 2
Existing Wastewater Collection System
N-129-60-20-42-WP-R-WWMP
2-7 City of Stockton
Wastewater Master Plan Update
September 2022
As indicated in Table 2-3, parcels designated as Residential land use account for approximately 90 percent of all parcels b y count, and approximately 41 percent of all parcels by area, with the large majority of those having a Low-Density Residential land use designation. In terms of parcels with non -zero water demands, Residential land use parcels account for approximately 9 4 percent of all parcels by count and approximately 55 percent of all parcels by area. If non -zero water demands are taken as a measure of parcel occupancy, then approximately 87 percent of Residential parcels are occupied in terms of parcel count and approximately 64 percent are occupied in terms of parcel area. Of the non-residential land uses, the Commercial category makes up the largest group by parcel count (approximately 4,100 parcels), and the Industrial category makes up the largest group by parcel area (approximately 9,700 acres). Among the Industrial land use category, t here are 54 Signific ant Industrial Users (SIUs), which are summarized in Table 2-4.

2.2 EXISTING COLLECTION SYSTEM FACILITIES
The City’s existing wastewater collection system consists of gravity sewers, force mains, and pump stations. Information regarding these facilities, as reported in the City’s GIS database and provided by City staff, is presented below. City staff have indicated that the existing GIS information is subject to confirmation and/or revision. All pipeline quantities discussed here exclude lines that are indica ted as either abandoned or proposed in the City’s GIS database.

2.2.1 Gravity Sewers
The City’s wastewater collection system comprises just over 1,000 miles of gravity mains ranging from 4-inch diameter to 84-inch diameter. Table 2-5 provides a summary of gravity sewer pipelines by pipe diameter. As shown on Table 2-5, approximately 70 percent of existing gravity sewer pipes are 6-inch and 8-inch diameter. Approximately 1 percent are of unknown diameter or have a reported diameter that is shown as non-standard (e.g., 7-inch) and are therefore possibly misreported.

The gravity main materials are summarized in Table 2-6 and presented on Figure 2-3. The most common pipe materials are vitrified clay pipe (VCP) and polyvinyl chloride (PVC) pipe, which combined account for approximately 77 percent of the system by pipe length. An additional roughly 11 percent of the system is of unidentified pipe materials, with the remainder consisting of various other pipe materials.

The installation years for gravity mains are summarized in Table 2-7 and are presented on Figure 2-4.

According to the City’s GIS data, approximately 50 percent of the system was constructed between 1970 and 2010, 12 percent of the system has an unknown installation year. The data indicate that less than 1 percent of the lines were constructed since 2010. The remaining approximately 37 percent of the system has an installation date before 1970, with the earliest installation year listed as 1890.

2.2.2 Force Mains
The City’s existing wastewater collection system contains approximately 37 miles of active force mains ranging from 2 -inch diameter to 42 -inch diameter. Force main pipe diameters by pipe length are summarized in Table 2-8.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 2-4. Significant Industrial U
sers, City of Stockton
Significant Industrial
User Address
Maximum Allowable
Discharge, MG/month
Average 2019 Discharge,
MG/month(a) Comments
Adva
nced Industrial Coatings, Inc. 950 Industrial Drive -- -- Discharge limit and monitoring data not provided Aero Turbines, Inc. 6800 S. Lindbergh Street -- -- Discharge limit and monitoring data not provided American Biodiesel 809-C Snedeker Avenue 0.21 -- Monthly discharge not provided American Building Supply 1488 Tillie Lewis Drive 0.0063 0.0045 Discharge occurs year round Applied Aerospace Structures Corp 3437 S. Airport Way 0.65 0.2 Discharge occurs year round Aramark Uniform & Career Apparel, LLC 7679 S. Longe Street 6.93 4.67 Discharge occurs year round B & C Painting Solutions, Inc 107 Val Dervin Parkway -- -- Discharge limit and monitoring data not provided CALAMCO 2323 Port Road -- -- Discharge limit and monitoring data not provided California Department of Fish & Wildlife 2109 Arch Airport Road -- -- Discharge limit and monitoring data not provided California Tank Lines, Inc. 3105 S. El Dorado Street 1 0.34 Discharge occurs year round Campbell Soup Supply Company 760 Industrial Drive 65 20.45 Discharge occurs June - October Cintas Corporation #922 1877 Industrial Drive 3.6 2.65 Discharge occurs year round City of Stockton Delta WTP 11373 N. Lower Sacramento Road -- -- Discharge limit and monitoring data not provided Comtech Rotor Blades, LLC 6700 CE Dixon Street -- -- Discharge limit and monitoring data not provided Dameron Hospital - Main Hospital 525 W. Acacia Street 2.2 -- Monitoring data not provided Diamond Foods 1050 S. Diamond Street 4.7 1.31 Discharge occurs year round Donaldson Co., Inc. 1641 E. Citation Street 0.027 0.00365 Discharge occurs year round DTE Stockton, LLC 2526 W. Washington Street 5.5 3.16 Discharge occurs year round Dupont Market Inc 2716 E. Miner Street 3 1.62 Discharge occurs year round Duraflame West 1340 W. Washington Street 3.1 0.06 Discharge occurs year round Foodliner, Inc. 2467 E. Mariposa Road 0.51 0.18 Discharge occurs year round Heinz North America 6755 CE Dixon Street 0.012 0.007 Discharge occurs year round Ingredion Incorporated, Stockton Plant 1021 Industrial Drive 6 2.93 Discharge occurs year round Inland Industrial Tire North, Inc. 3039 Transworld Drive -- -- Discharge limit and monitoring data not provided International Paper 3550 Bozzano Road -- 0.037 Discharge limit not provided Le Tote 3021 Boeing Way 0.35 0.12 Discharge occurs year round Metal Finishing Solutions 1325 El Pinal Drive 0.15 0.097 Discharge occurs year round New Stockton Poultry, Inc. 302 S. San Joaquin Street 1.05 0.66 Discharge occurs year round Niagara Bottling, LLC 1025 Runway Drive 7.5 5.41 Discharge occurs year round Niagara Bottling, LLC 811 Zephyr St 811 Zephyr Street 7.86 5.18 Discharge occurs year round Old World Industries, LLC 812 Luce Avenue 0.44 0.12 Discharge occurs year round Pacific Spray Dry (Vapore Technology) 818 McCloy Avenue 0.6 0.037 Discharge occurs year round Port City Operating Company, LLC 1800 N. California Street -- -- Discharge limit and monitoring data not provided Premier Coatings, Inc. 7910 S. Longe Street 0.05 0.028 Discharge occurs year round Production Chemical 1000 E. Channel Street -- -- Discharge limit and monitoring data not provided S J County General Hospital 500 Hospital Road 1.7 -- Monitoring data not provided San Joaquin Regional Rail Commission 1020 E. Alpine Avenue 0.1 -- Monitoring data not provided San Joaquin Regional Transit District 2849 E. Myrtle Street 0.001 -- Monitoring data not provided Shepard Bros 4407 Giannecchini Lane 0.028 0.019 Discharge occurs year round Simplot Grower Solutions 4863 E Carpenter Road -- -- Discharge limit and monitoring data not provided SJ Co French Camp Complex 1005 W. Mathews Road 51 8.71 Discharge occurs year round Stockton Sanitary Washrack Group 1505 Navy Drive 0.64 0.15 Discharge occurs year round Sulfuric Acid Trading Company, Inc. 2829 W. Washington Street 0.048 0.012(b) Discharge occurs y ear round
Sumiden Wire Products Corp. 1412 El Pinal Drive 2.1 0.49 Discharge occurs year round Tankerwash USA, Inc. 743 W. Anderson Street 1.3 0.85 Discharge occurs year round Tiger-Sul Products LLC 65 Stork Road -- -- Discharge limit and monitoring data not provided Truck Tub International, Inc. 1707 French Camp Turnpike Road 0.0775 0.054 Discharge occurs year round UniFirst Corporation 819 N. Hunter Street 3.25 1.93 Discharge occurs year round Valimet, Inc. 431 Sperry Road -- -- Discharge limit and monitoring data not provided Valley Plating 1236 N. Filbert Street -- -- Discharge limit and monitoring data not provided Value Products, Inc. 2128 Industrial Drive 0.038 0.017 Discharge occurs year round Western Square Industries, Inc. 1621 N. Broadway Avenue 0.012 -- Monitoring data not provided Wilmar Oils and Fats, LLC 2008 Port Road 1 0.24 Discharge occurs year round Yosemite Foods, Inc. 4221 E. Mariposa Road 5.1 3.7 Discharge occurs year round (a) Unless othe
rwise noted, the 2019 average monthly discharge is to reflect pre-pandemic conditions. (b) The 2020 average monthly discharge is displayed due to lack of 2019 discharge data. n\c\129\60-20-=42
City of Stockton
Wast
ewater Master Plan Update
Last Revised: 02-17-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 2
Existing Wastewater Collection System
N-129-60-20-42-WP-R-WWMP
2-9 City of Stockton
Wastewater Master Plan Update
September 2022

2.2.1 Pump Stations
There are 35 pump stations included in the City’s GIS data that are within or tributary to the City’s wastewater collection system, as shown on Figure 2-2. Key pump station information, including station name, system number, rated firm capacity, and station type (fixed -speed versus variable speed), are summarized in Table 2-9. The firm capacity is defined as the maximum pumping capacity at the pump station with the largest pump out of service. Information on pump capacities was not available for the privately-owned pump stations shown in Table 2-9.

Table 2-5. Gravity Mains by Diameter(a)
Pipe Diameter, inches Count Length, feet
Portion of Total
Length, percent
4 694 50,924 0.96
6 7,534 1,576,999 29.7
8 8,265 2,146,339 40.5
10 1,329 358,754 6.8
12 1,482 402,014 7.6
14 21 5,183 0.10
15 367 110,666 2.1
16 98 28,273 0.53
18 310 86,221 1.6
20 42 16,963 0.32
21 55 15,385 0.29
24 365 110,693 2.1
27 117 37,582 0.71
30 186 69,807 1.3
33 41 14,573 0.27
36 124 50,316 0.95
42 117 48,166 0.91
48 142 59,359 1.1
54 17 9,603 0.18
60 4 473 0.009
66 22 9,241 0.17
72 58 25,828 0.49
78 2 166 0.003
84 6 1,989 0.037
Unknown/Non-standard 1,118 68,492 1.3
TOTAL 22,516 5,304,011 100
(a) Data summarized from the City of Stockton's GIS sanitary line feature class transmitted, July 2020. Excludes pipes designated as abandoned or proposed.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 2
Existing Wastewater Collection System
N-129-60-20-42-WP-R-WWMP
2-10 City of Stockton
Wastewater Master Plan Update
September 2022
Table 2-6. Gravity Mains by Pipe Material(a)
Pipe Material Count Length, feet
Portion of Total
Length, percent
Vitrified Clay (VCP) 9,253 2,461,957 46.4
Polyvinyl Chloride (PVC) 6,457 1,632,961 30.8
Reinforced Concrete (RCP) 653 246,787 4.7
Reinforced Plastic Mortar (RPM) 447 123,402 2.3
Polyethylene (PE) 239 68,652 1.3
Asbestos Cement Pipe (ACP) 171 46,765 0.9
Acrylonitrile Butadiene Styrene (ABS) 135 35,050 0.7
Ductile Iron Pipe (DIP) 96 22,867 0.4
Unknown 4,708 573,164 10.8
Other Materials 314 77,074 1.5
(a) Data summarized from the City of Stockton's GIS sanitary line feature class transmitted in July 2020. Excludes pipes designated as abandoned or proposed.

Table 2-7.Gravity Mains by Installation Year(a)
Installation Year Count Length, feet
Portion of Total
Length, percent
Pre-1910 925 235,948 4.4
1910s 1,059 295,228 5.6
1920s 971 234,904 4.4
1930s 374 90,058 1.7
1940s 1,597 408,097 7.7
1950s 1,540 415,543 7.8
1960s 1,148 288,657 5.4
1970s 2,254 572,240 10.8
1980s 2,214 584,444 11.0
1990s 2,660 657,545 12.4
2000s 2,913 812,125 15.3
2010s 182 48,600 0.9
Unknown 4,679 660,620 12.5
(a) Data summarized from the City of Stockton's GIS sanitary line feature class transmitted in July 2020. Excludes pipes designated as abandoned or proposed.

ATTACHMENT C
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DRAFT EXHIBIT 1
0 1.50.75
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Figure 2-3
Collection System
Pipe Material
City of Stockton
Wastewater Master Plan Update
Pipe by Material
Asbestos-Cement
Cast Iron
Concrete
Corrugated Metal
Ductile Iron
PolyVinyl Chloride
Polyethylene
Polypropylene
Vitrified Clay
Other
City Limits
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 2\Figure 2-3. Collection System Pipe Material.mxd - jsteiner - 6/15/2022 Notes:

1. Data summarized from the City of Stockton's GIS.

Excludes pipes designated as abandoned or proposed.

TF C W RURegional Wastewater Control Facility

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
0 1.50.75
Miles

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Figure 2-4
Collection System
Pipe Installation Year
City of Stockton
Wastewater Master Plan Update
Pipe by Installation Year
1940s or earlier
1950s
1960s
1970s
1980s
1990s
2000s
2010s
No Data Available
City Limits
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 2\Figure 2-4. Existing Wastewater Collection System by Installation Year.mxd - jsteiner - 6/15/2022 Notes:

1. Data summarized from the City of Stockton's GIS.

Excludes pipes designated as abandoned or proposed.

TF C W RURegional Wastewater Control Facility

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 2
Existing Wastewater Collection System
N-129-60-20-42-WP-R-WWMP
2-13 City of Stockton
Wastewater Master Plan Update
September 2022
Table 2-8. Force Main Quantities by Pipe Diameter(a)
Pipe Diameter, inches Segment Count(b) Length, feet
2 1 785
4 2 225
6 5 2,902
8 28 14,448
10 32 32,429
12 53 26,023
14 2 3,239
15 1 48
16 6 3,211
18 9 432
20 2 433
24 56 32,495
30 60 44,414
33 36 28,624
36 11 2,191
42 5 5,226
unknown 2 176
TOTAL 311 197,301
(a) Data summarized from the City of Stockton's GIS sanitary line feature class transmitted in July 2020. Excludes pipes designated as abandoned or proposed.
(b) The GIS data is organized such that one force main may consist of multiple segments.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 2-9. Wastewat
er Pump Station Summary Information
Station ID Na
me/Location System Pump Manufacturer No. of Pumps Pump Capacity Ratings, gpm Firm Capacity, mgd Pump Speed 22D008 14-Mile Slough 10 Fairbanks Morse/Flygt 4 2000/2000/????/???? (a) Variable 25H013 Alexandria & 14-Mile Slough (Quail Lakes) 10 Vaughan 2 1370/1370 1.97 Constant 42U054 Arch Road 10 Flygt 4 1190/2425/2425/2425 8.70 Variable 23P010 Blossom Ranch 10 Vaughan 3 450/450/450 1.30 Constant 28D015 Brookside Estates 10 Fairbanks Morse 4 2000/2000/2000/2000 8.64 Variable 29D029 Buckley Cove 10 Flygt 2 205/205 0.30 Constant
24L070 Camanche & Ridgeway 10 Fairbanks Morse 3 835/835/835 2.40 Constant 46M005 County Pump Station (Hospital/Mathews) 10 Aurora 3 750/750/750 2.16 Constant 29G014 County Pump Station (Pacific Garden/Kirk) 10 Flygt 2 600/600 0.86 Constant 22E031 Cumberland & 5-Mile Creek 10 Vaughan 3 1500/1500/1500 4.32 Variable 20G059 Don Avenue & Santiago 10 Vaughan 2 550/550 0.79 Constant 32S052 Drake & Highway 99 10 Smith & Loveless Inc. 3 1230/1230/1230 3.54 Constant 43N022 Grupe Business Park 10 Paco 2 600/600 0.86 Constant 18E073 Kelly & Mosher Slough 10 Vaughan/Fairbanks Morse 4 1000/1000/1000/1000 4.32 Variable 33T064 Main Street & Coolidge Avenue (Wilhelma) 10 Flygt 2 286/286 0.41 Variable 28G078 March-Brookside & I-5 10 Flygt 2 800/800 1.15 Constant 28H040 Mission & Del Rio 10 Vaughan 1 125 0 Constant
22Q001 Origone 10 Flygt 4 1200/1200/1200/1200 5.18 Variable 30N047 Parkview (College Park) 10 (a) 2 (a) (a) Constant 32G072 Pixie Woods Grinder Pump 10 Liberty 1 (a) (a) Constant 22F103 Plymouth & 5-Mile Creek 10 Smith & Loveless Inc. 2 870/870 1.25 Constant 18H049 Private Pump Station (Thorton) 10 (a) 0 (a) (a) Constant 23K037 Private Pump Station (Glendora) 10 (a) 0 (a) (a) Constant 34E001 Private Pump Station (Ellsberg) 10 (a) 0 (a) (a) Constant 33M045 Private Pump Station (Weber) 10 (a) 0 (a) (a) Constant 26P045 Sanguinetti 10 Flygt 2 3600/3750 15.98 Variable
36U044 Sinclair Avenue & Highway 4 (Duck Creek) 10 Flygt 3 1500/1500/1500 4.32 Constant 31H086 Smith Canal & Fontana 10 Vaughn /Aurora 5 4520/5710/8600/8600/7500 37.92 Variable 30M112 St. Joseph's Medical Center 10 Flygt 2 419/419 0.60 Constant 22G053 Swenson & 5-Mile Creek (North Pump Station) 10 Worthington 4 3500/8000/3500/2000 20.16 Variable 29E007 Temporary Pump Station - Brookside Estates (Abandoned) 10 (a) 0 (a) (a) Constant 19H072 Thornton & Davis (Stonewood) 10 Vaughan 2 850/850 1.22 Constant 30P069 Waterloo & Roosevelt (East Stockton-North) 10 Vaughan 3 950/950/950 2.74 Constant 16B030 Westlake 10 Vaughan 3 1510/1510/1510 4.35 Constant 42K005 Weston Ranch 10 Vaughan/Fairbanks Morse 4 1300/1300/8500/8500 15.98 1 variable, 3 constant (a) Pump m
ake and/or capacity information not available
N-129-60-20-42-WP-R-W
WMP
CIty of Stockt
on
Wastewater Master Plan Update
Last Revised: 09-02-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
3-1 City of Stockton
Wastewater Master Plan Update
September 2022
CHAPTER 3
Existing Wastewater Flows
The purpose of this chapter is to present information on existing dry and wet weather flow conditions in the City of Stockton wastewater collection system. The major topics covered in this chapter include:
• Wastewater Flow Components
• Flow Metering Locations
• Rainfall Results
• Flow Monitoring Results
• Investigation of Flow Splits

3.1 WASTEWATER FLOW COMPONENTS
Key components of wastewater collection system flows include the following:
• Average Dry Weather Flow
• Sanitary Peak Flow
• Infiltration and Inflow
• Peak Wet Weather Flow

3.1.1 Average Dry Weather Flow
Average dry weather flow (Qa) is a term that describes average wastewater flow conditions that typically occur later in the dry season when groundwater infiltration into the collection system is at a seasonal minimum and prior to the onset of significant rainfall events. Depending on groundwater elevations and system porosity, Qa may have a component of groundwater infiltration that is present year -round.

Otherwise, Qa represents sanitary flow contributions from residential, commercial, institutional, and industrial dischargers to the collection system.

3.1.2 Sanitary Peak Flow
Sanitary peak flow is defined as the diurnal flow peak during baseline dry weather flow conditions. The timing of sanitary peak flow typically depends on the contributing land use types. Residential dischargers tend to produce higher flows in the morning hours and in the evening hours, while commercial dischargers tend to have steady discharge during business hours but very low discharge outside of business hours.

Industrial dischargers have flow patterns that depend upon their individual processes.

3.1.3 Infiltration and Inflow
The term infiltration and inflow (I&I) refers to the portion of wastewater flow that does not come from indoor sanitary flow generating activities, but instead enters the collection system in the form of elevated groundwater infiltration (over an d above the year -round groundwater infiltration component that may be present in the Qa), and/or flows entering the collection system during and immediately after rainfall events. This latter component is referred to as rainfall-dependent I&I, and is defin ed as storm-induced flow that enters the collection system through porous and/or defective maintenance holes (MHs), sewer mains and service laterals, or illicit connections such as roof leaders that otherwise should be connected to storm drain facilities. The magnitude of rainfall-dependent I&I flows is related to the intensity and duration of the rainfall and the degree of soil saturation and increas ed groundwater levels arising from antecedent rainfall conditions.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 3
Wastewater Flows
N-129-60-20-42-WP-R-WWMP
3-2 City of Stockton
Wastewater Master Plan Update
September 2022

3.1.4 Peak Wet Weather Flow
Peak wet weather flow (Qp) is composed of sanitary flow plus a combination of groundwater infiltration and rainfall-dependent I&I and is generally defined as the highest flow that occurs during a given storm or wet season. The magnitude of the peak wet weather fl ow is thus dependent on storm intensity and duration, antecedent rainfall conditions, and the time of day at which the peak I&I occurs. The highest Qp values are typically associated with large, intense storm events, and tend to be greater following a series of other storm events after soils become saturated. Moreover, a large storm occurring during the day will have a higher Qp than a similar storm occurring at night due to the elevated sanitary flows that occur during the day.

3.2 FLOW METERING LOCATIONS
For this Master Plan, a collection system flow monitoring study was conducted that covered the period of late October 2020 through mid-March 2021. The flow monitoring study provided the data used to perform an assessment of both dry and wet weather flow conditions throughout the City’s collection system.

Under the flow monitoring study, a total of 25 temporary area-velocity (AV) flow meters were deployed in sewer lines at various locations throughout the City in support of this Master Plan . The flow metering locations are depicted on Figure 3-1 and are summarized in Table 3-1. Graphical representations of each flow metering location are presented in Appendix A of this report.

The flow metering locations were chosen through a collaboration of West Yost and City staff and were chosen to satisfy the following goals:

1. Capture a significant portion of all the contributing collection system sub-areas (Systems 1-10).

2. Capture the full range of different land uses throughout the City.

3. Capture both wet and dry weather flows.

4. Determine dry weather baseline flows and peak wet weather flows.

5. Establish flow conditions at areas of concern identified by the City.

6. Repeat previous monitoring locations (where appropriate) to provide continuity of data.

3.3 RAINFALL RESULTS
A total of seven temporary rain gauges were deployed at locations throughout the City in support of the flow monitoring study . The rain gauge locations are depicted on Figure 3-1. Rainfall statistics for the months of October 2020 through March 2021 are summarized in Table 3-2. As indicated in Table 3-2, reported rainfall amounts were highest at the East gauge and lowest at the Northwest gauge.

The total rainfall for the monitoring period, averaged among the seven rain gauges, was 7.20 inches. This result compares with the National Oceanic and Atmospheric Administration (NOAA) long-term average of

13.99 inches over the same period. Thus, the observed rainfall was only about half the long-term average.

The most significant storm event of the season occurred on January 27 and 28, 2021, which produced

2.92 inches of rain over 48 hours when averaged over the seven gauges. The next most significant event occurred on December 13, 2020, which produced 1.04 inches of rain over 24 hours when averaged over the seven gauges.

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N-129-60-20-42-WP-R-WWMP
City of Stockton
Wastewater Master Plan Update
June 2021
Table 3-1. Summary of Flow Monitoring Locations
Site ID MH ID GIS Pipe D, in Location Tributary Area
1-1 22E038 27 Cumberland Place and Stone River Circle Southern portion of System 1 2-1 23G001 48 Alexandria Place and Lincoln High School Southern portion of System 2 2-2 22H056 36 West Lincoln Avenue west of Richmond Place Northeastern portion of System 2 3-1 30K050 24 North Pershing Avenue and Elmwood Avenue Northeastern portion of System 3 3-2 30K109 30 North Orange Street north of Middlefield Avenue Southeastern portion of System 3 3-3 29G003 18 Calariva Drive and North Stiles Place Country Club area of System 3 4-1 32R081 18 East Marsh Street and Burkett Avenue Southern portion of System 4 4-2 30P060 18 Waterloo Road and Hiawatha Avenue Northern portion of System 4 4-3 30Q038 10 North Filbert Street and East Anita Street Flow split within System 4 4-4 31R031 16 East Fremont Street west of North Filbert Street Flow split within System 4 5-1 35M014 24 West Scotts Avenue and South Van Buren Street Portions of Systems 4 and 6 5-2 34M018 24 South Lincoln Street and West Washington Street Portions of Systems 5 and 6 6-1 35R026 24 East Charter Way and Mariposa Road Southeastern portion of System 6 6-2 33P111 33 Della Street north of East Hazelton Avenue Portions of Systems 4 and 6 6-3 34N024 27 Church Street and Aurora Street Portions of Systems 4 and 6 6-4 36M046 24 West Charter Way east of I-5 Southern portion of System 6 6-5 35N004 36 East Worth Street east of South Stanislaus Street Southeastern portion of System 6 6-6 34M050 27 East Church Street and South Center Street Portions of Systems 4 and 6 7-1 39P004 42 Ralph Avenue east of Perlman Drive Eastern portion of System 7 7-2 38K038 72 West 8th Street west of South Fresno Avenue Portions of Systems 7, 8, and 14 8-1 38J059 48 Houston Avenue south of Tilden Park Street Western portion of System 8 8-2 42Q007 27 Gibraltar Court south of Industrial Drive Central portion of System 8 8-3 41Q020 33 South Airport Way south of Industrial Drive Airport area of System 8 8-4 41R005 42 Industrial Drive east of South Airport Way Northeastern portion of System 8 10-1 18D012 54 Bear Creek levee south of Otto Drive System 10

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±P u m p S t a t i ons
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C i t y of S t oc kt on L i m i t s C i t y of S t oc kt on S p he r e of I nf l u e nc e

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Chapter 3
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N-129-60-20-42-WP-R-WWMP
3-5 City of Stockton
Wastewater Master Plan Update
September 2022
Table 3-2. Stockton Temporary Rain Gauge Results, October 2020 through March 2021 Month
Temporary Rain Gauge Location
Northwest Northeast
Center-
North West Center East South
7-Gauge
Avg
October 0 0 0 0 0 0.01 0 0
November 0.40 0.19 0.25 0.20 0.24 0.18 0.06 0.22
December 1.51 2.31 2.17 1.90 2.00 2.55 2.00 2.06
January 2.57 3.49 3.72 2.79 3.19 4.72 4.04 3.50
February 0.73 1.12 0.94 0.73 0.61 1.25 0.88 0.89
March 0.43 0.69 0.58 0.60 0.52 0.43 0.42 0.53
Total 5.63 7.80 7.65 6.22 6.56 9.15 7.39 7.20
January 27–28 2.06 2.91 3.19 2.37 2.70 3.92 3.28 2.92
Storm event return period information for the January 27 and 28, 2021 storm event was estimated using NOAA online resources. The estimated return periods (in years) for that event are summarized in Table 3-3. The peak 6-hour, 12-hour, and 24-hour rainfall totals represent return periods in the 1.5 -year to 1.7-year range; however, the peak 48-hour rainfall was an 8-year event. Specifically, a 1.5-year, 24-hour event on January 27, 2021 was immediately followed by a 1.1 -year, 24-hour event on January 28, 2021, which resulted in an 8-year return period for the 48-hour rainfall total.

Table 3-3. Return Period Information, January 27 and 28, 2021 Storm Event Duration Max Rainfall, in Start Time Return Period, years 6-hour 0.88 1/27/2021 13:45 1.7
12-hour 1.12 1/28/2021 10:40 1.5
24-hour 1.55 1/26/2021 21:05 1.5
48-hour 2.92 1/26/2021 23:00 8.0
Source: NOAA National Weather Service
While event rainfall was substantial, antecedent rainfall preceding the January 27 and 28, 2021 event was minor, with a prior 7 -day rainfall of 0.40 inches, a prior 30 -day rainfall of 0.66 inches, and a season -to- date rainfall of 2.83 inches. As a result, saturated soils and high groundwater levels, which may contribute significantly to peak I&I conditions, were not present for that event.

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Chapter 3
Wastewater Flows
N-129-60-20-42-WP-R-WWMP
3-6 City of Stockton
Wastewater Master Plan Update
September 2022

3.4 FLOW MONITORING RESULTS
Key flow monitoring results discussed in this section include:
• Flow and I&I Statistics
• Evidence for Backwater Conditions

3.4.1 Flow and I&I Statistics
Flow and I&I at the RWCF influent for the period up to, including, and immediately following the January 27 and 28, 2021 storm event is shown in Figure 3-2. Flow and I&I statistics for the 25 temporary flow metering sites and from the RWCF are presented in Table 3-4. Because Sites 4 3 and 4 4 are both immediately downstream of the same flow split, the results for those two sites are shown in the table both separately and as a combined flow. Key flow and I&I statistics shown in Table 3-4 include:
• Data Period: Start and end dates
• Qa: The average dry season flow, typically calculated from flows measured during October and November 2020
• Qp: The maximum observed hourly average flow rate
• Time: Peak Flow
• Peaking Factor (PF): The peak flow divided by the Qa
• Maximum Storm I&I: The maximum calculated I&I rate during rainfall periods • Tributary Area: The total flow-producing parcel acreages for each flow meter • Maximum I&I Rate: The max storm I&I divided by the tributary area Notable findings from Table 3-4 include the following:

1. Peak flows occurred during the January 27–28, 2021 storm event at all metering sites except 1-1, 2-1, 3-3, 4-2, 4-4, and 10 1, none of which had peak flows associated with significant storm events.

2. The peak flow at the RWCF was 55.35 mgd.

3. The City-wide peak I&I rate during the January 27 and 28, 2021 storm event is approximately 1,000 gallons per day (gpd) per acre.

4. The tributary areas associated with Sites 1-1, 2-1, 3-2, 4-3+4-4, 6-2, 6-3, 6-4, and 7-1 all had maximum I&I rates well in excess of the City-wide total.

5. The tributary areas associated with Sites 8-3 and 10-1 had peak I&I rates well below the City-wide total.

6. I&I rates could not be calculated for Sites 4-3, 4-4, 5-1, 5-2, 6-5 and 6-6 due to the presence of one or more upstream flow splits that make it impossible to define the tributary area for the individual meters.

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Table 3-4. Flow
and I&I Statistics
Metering Site Start Date
End Date Qa, mgd
Qp, mgd T
ime of Peak Flow PF Max Storm I&I, mgd Tributary Acreage, acres Max I&I Rate, gpd/acre (a) 1-1 10/20/2020 3/15/
2021 0.98 3.91 Nov-19-2020 5:55 4.0 2.04 690 3,000
2-1 10/13/2020 3/15/2021 2.86 9.51 Dec-14-2020 13:20 3.3 6.14 2,080 3,000 2-2 10/13/2020 3/15/2021 3.98 7.35 Jan-27-2021 15:35 1.8 2.58 2,990 900 3-1 10/24/2020 3/15/2021 1.02 2.12 Jan-27-2021 18:05 2.1 0.86 950 900 3-2 10/13/2020 3/15/2021 1.61 4.22 Jan-27-2021 17:45 2.6 2.27 1,120 2,000 3-3 11/3/2020 3/15/2021 0.19 1.19 Nov-3-2020 9:10 6.3 0.27 250 1,100 4-1 10/14/2020 3/15/2021 0.57 1.85 Jan-28-2021 13:40 3.3 1.14 900 1,300 4-2 10/20/2020 3/15/2021 0.53 1.86 Feb-22-2021 10:25 3.5 0.82 550 1,500 4-3 10/20/2020 3/15/2021 0.029 0.39 Jan-28-2021 16:15 13.3 0.37 (b) (b) 4-4 10/24/2020 3/13/
2021 0.094 0.64 Feb-21-2021 18:45 6.8 0.15 (b) (b)
4-3+4-4 10/24/
2020 3/13/2021 0.12 0.57 Jan-28-2021 16:35 4.8 0.42 150 2,800 5-1 11/27/2020 3/15/2021 1.02 2.69 Jan-28-2021 14:50 2.7 1.65 (b) (b) 5-2 10/14/2020 3/12/
2021 0.51 1.59 Jan-28-2021 17:50 3.1 0.93 (b) (b)
6-1 10/27/2020 3/15/
2021 0.41 0.91 Jan-28-2021 18:10 2.2 0.38 300 1,300
6-2 10/14/2020 3/15/2021 0.63 3.46 Jan-28-2021 20:55 5.5 2.60 480 5,400 6-3 10/14/2020 3/15/2021 0.96 3.11 Jan-28-2021 13:15 3.2 1.91 1,010 1,900 6-4 11/14/2020 3/15/2021 0.55 2.75 Jan-28-2021 20:55 5.0 2.00 390 5,100 6-5 10/20/2020 3/15/2021 0.65 3.75 Jan-28-2021 21:10 5.8 2.92 (b) (b) 6-6 10/14/2020 3/15/
2021 1.07 3.95 Jan-28-2021 13:40 3.7 2.62 (b) (b)
7-1 10/14/2020 3/15/
2021 1.29 3.59 Jan-28-2021 14:00 2.8 2.02 930 2,200
7-2 11/14/2020 3/15/2021 3.26 8.04 Jan-28-2021 18:25 2.5 3.75 5,180 700 8-1 11/14/2020 3/15/2021 1.35 2.54 Jan-27-2021 17:20 1.9 0.94 1,080 900 8-2 10/14/2020 3/15/2021 0.40 1.06 Jan-27-2021 16:50 2.6 0.44 420 1,000 8-3 10/14/2020 3/15/2021 0.42 0.85 Jan-25-2021 11:40 2.0 0.37 1,390 300 8-4 10/14/2020 3/15/2021 0.52 1.14 Jan-27-2021 17:55 2.2 0.45 560 800 10-1 10/20/2020 3/15/2021 2.16 3.60 Nov-26-2020 13:00 1.7 0.79 2,340 300 RWCF 10/1/2020 2/28/2021 24.01 55.35 Jan-28-2021 21:59 2.3 24.80 24,970 1,000 (a) Round
ed off to the nearest 100 gpd/acre.
(b) Tributary acreage and I&I rate cannot be calculated do to one or more upstream flow splits. n\c\129\
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Last Revised: 06-09-2022

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N-129-60-20-42-ENG
-FDA-WPCFOCT-FEB2021
City of Stoc
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Wastewater Master Plan Update
Last Revised: 03-25-22
0 0.1

0.2 0.3

0.4 0.5

0.6 0.7

0.80 10
20 30
40 50
60 70
80 Jan-25
Jan-26
J
an-27
Jan-28
Jan-29
Jan-30
Jan-31
Rain, inches/hour
Flow, mgd
Figure 3
-2. RWCF Influent Flows and I&I, January 25 through 30, 2021 I&I Hourly
Rain Hourly
Flow

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Chapter 3
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September 2022

3.4.1 Evidence for Backwater Conditions
The temporary flow metering sites use area-velocity meter technology that measures flow depth, flow velocity and flow rate on 5 -minute intervals. The measurement of both depth and velocity allow for an assessment of whether a given line is flowing unimpeded, or whether backwater conditions exist.

Table 3-5 presents the following relevant information for each metering site:
• Pipe Diameter (D)
• Average Flow Depth (d): The long-term average measured pipe flow depth • Average d/D: The ratio between the average measured flow depth and the pipe diameter • Maximum Flow Depth (d): The maximum measured pipe flow depth • Maximum (Max d/D): The maximum ratio between the measured flow depth and the pipe diameter
• Time of Maximum Depth
• Maximum Surcharge: The maximum surcharge (if any) above the pipe crown • Minimum Headspace: The remaining MH headspace associated with the maximum surcharge
• Average Velocity (Avg V): The long-term average measured pipe flow velocity • Minimum Velocity (Min V): The minimum instantaneous pipe flow velocity during the data period
• Depth-Velocity Correlation (R): The calculated correlation coefficient between the measured depth and measured velocity readings
In general, a correlation coefficient above 0.5 indicates unimped ed flow conditions, a correlation coefficient of 0 to 0.5 indicates partially impeded flow conditions, and a negative correlation coefficient indicates significantly impeded flow conditions. For purposes of this analysis, the identification of backwater conditions is accomplished through comparison of maximum flow depths with the given pipe diameter, through visual inspection of depth -velocity scatterplots at each site, and through the consideration of the R -value for each metering location. Figure 3-3 shows scatterplots and associated correlation coefficients for metering Site 6-3 and metering Site 1-1, which represent the highest and lowest R-values, respectively, of the 25 temporary flow metering sites.

It should be noted that a power failure during the January 27 and 28, 2021 storm resulted in certain pump stations being non -operational during that event, which contributed to the observed backwater conditions at metering sites 1 -1, 2 -1, 2-2, 4 -2, and 10 -1. However, those sites also routinely exhibit backwater conditions during dry weather flow conditions.

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Table 3-5. F
low Depth and Velocity Statistics
Metering Site Pipe D,
in Avg Depth (d), in Avg d/D Max Depth (d), in Max d/D Time of Max Depth Max Surcharge, ft Min Headspace, ft Avg V, ft/sec Min V, ft/sec D-V Correlation (R) 1-1 27 37.6 1.39 91.8 3.40 Nov-19 5:50 5.4 11.5 0.401 -0.284 -0.845 2-1 48 34.9 0.73 117.4 2.45 Dec-14 13:05 5.8 8.8 0.500 0.000 -0.370 2-2 36 25.9 0.72 110.0 3.05 Dec-14 13:15 6.2 12.5 1.308 0.121 -0.587 3-1 24 9.1 0.38 13.5 0.56 Jan-28 22:35 -- -- 1.444 0.810 0.831 3-2 30 8.2 0.27 14.8 0.49 Jan-28 17:25 -- -- 2.045 1.284 0.855 3-3 18 3.1 0.17 9.7 0.54 Nov-3 9:40 -- -- 0.974 -1.015 0.901 4-1 18 5.6 0.31 29.5 1.64 Nov-19 7:15 1.0 5.8 1.798 0.029 0.896 4-2 18 22.5 1.25 247.8 13.77 Feb-21 21:25 19.2 7.0 0.731 0.005 -0.292 4-3 10 3.7 0.37 70.9 7.09 Feb-21 20:40 5.1 11.0 0.406 -0.130 0.269 4-4 14 3.3 0.23 8.8 0.63 Jan-28 16:25 -- -- 0.701 0.010 0.836 5-1 24 7.3 0.30 29.5 1.23 Jan-28 20:20 0.5 11.8 1.985 0.860 0.637 5-2 24 8.9 0.37 45.9 1.91 Jan-28 18:10 1.8 12.2 0.876 0.210 0.137 6-1 24 7.0 0.29 17.2 0.72 Jan-28 22:00 -- -- 0.828 0.240 0.826 6-2 30 8.0 0.27 18.8 0.63 Jan-28 21:25 -- -- 0.866 0.264 0.843 6-3 27 6.4 0.24 14.1 0.52 Jan-28 13:40 -- -- 1.879 0.129 0.932 6-4 24 9.1 0.38 16.8 0.70 Jan-28 21:05 -- -- 0.790 0.108 -0.027 6-5 36 10.5 0.29 70.6 1.96 Jan-28 21:35 2.9 17.3 0.757 0.379 0.315 6-6 27 6.8 0.25 13.5 0.50 Jan-28 14:05 -- -- 2.014 0.612 0.930 7-1 42 8.3 0.20 17.7 0.42 Jan-28 14:55 -- -- 1.483 0.281 0.263 7-2 72 12.3 0.17 20.2 0.28 Jan-28 22:20 -- -- 1.571 0.669 0.838 8-1 48 8.7 0.18 12.2 0.25 Feb-7 13:50 -- -- 1.310 0.038 0.576 8-2 27 6.8 0.25 13.7 0.51 Oct-15 10:15 -- -- 0.769 0.056 0.307 8-3 33 4.4 0.13 6.8 0.21 Jan-22 15:55 -- -- 1.178 0.389 0.732 8-4 42 2.9 0.07 5.1 0.12 Jan-11 12:50 -- -- 2.741 1.218 0.447 10-1 54 8.5 0.16 76.3 1.41 Mar-1 23:25 1.9 18.8 2.179 0.000 -0.291 n\c\129\60-20-42\Wp\R
CIty of S
tockton
Wastewater Master Plan Update
Last Revised: 06-09-2022

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Figure 3-3
: Level-Velocity Scatterplots and Correlation Coefficients (R) 0 2
4 6
8 10
12 14
16 0 0.5 1 1.5 2 2.5 3
Level (in)
Vel (fps)
Site 6
-3 Level-Velocity Scatterplot
R = 0.932
0 10
20 30
40 50
60 70
80 90
100
-0.5 0 0.5 1 1.5 2 2.5
Level (in)
Vel (fps)
Site 1
-1 Level-Velocity Scatterplot
R = -0.845
N-129-60-20-42-ENG
-FDA-All Flows
City of Stockt
on
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Plan Update
Last Revi
sed: 03-25-22

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Based on a review of the depth-velocity data with consideration of the collection system configuration, the following conclusions have been reached:
• Site 1-1: This site has no clear diurnal flow patterns, frequently reports negative flows, and is frequently submerged, with an average d/D value of 1.39. The maximum observed flow depth was approximately 92 inches, which is 3.4 times the pipe diameter, and represents approximately 5.4 feet of surcharging in a MH with a rim to crown depth of 16.7 feet (per the City’s GIS) leaving 11.5 feet of additional headspace. The R-value at this site was –0.845, which is the lowest of all 25 sites. The metering location is just upstream of the Cumberland & Five Mile Creek Pump Station (PS) in one of two large diameter inlets of a junction MH, the other inlet of which receives flow from the Kelly & Mosher PS. It therefore appears that the Cumberland & Five Mile Creek PS is either not keeping up with the incoming flows, or the pump set points are such that the upstream sewers frequently surcharge. Moreover, it appears that the operation of the Kelly & Mosher PS pushes flow back up into the flow metered line on a regular basis, resulting in negative flow velocities at the metering location. • Site 2-1: This site had a maximum observed flow depth of approximately 117 inches, which is 2.5 times the pipe diameter, and represents approximately 5.8 feet of surcharging in a MH with a rim to crown depth of 14.5 feet (per the City’s GIS) leaving 8.8 feet of additional headspace. The R-value at this site was –0.370, which indicates frequent backwater conditions. The metering location is just upstream of the Swenson (North) PS. It therefore appears that the Swenson PS is either not keeping up with the incoming flows, or the pump set points are such that the upstream sewers frequently surcharge. • Site 2-2: This site had a maximum observed flow depth of approximately 110 inches, which is 3.1 times the pipe diameter, and represents approximately 6.2 feet of surcharging in a MH with a rim to crown depth of 18.7 feet (per the City’s GIS), leaving 12.5 feet of additional headspace. The R-value at this site was –0.587, which indicates frequent backwater conditions. The metering location is just upstream of the Swenson PS. It therefore appears that the Swenson PS is either not keeping up with the incoming flows, or the pump set points are such that the upstream sewers frequently surcharge. • Site 4-1: This site had one episode on November 19, 2020 where the depth, velocity, and flow all spiked upward, and the d/D value peaked at 1.64, which equates to a maximum surcharge of 1.0 feet in a MH with a rim to crown depth of 6.7 feet (per the City’s GIS).

Otherwise, the site operated without surcharging and with unimpeded flows. The site is a relatively short distance downstream of the Drake & Highway 99 PS, which suggests that the pump station ceased operating for a period on November 19, 2020, storing flow in its wet well and possibly the upstream gravity sewers and MHs, and then overloaded the downstream pipe when operations resumed.
• Site 4-2: This site has no clear diurnal flow patterns and is frequently submerged, with an average d/D value of 1.25. The maximum observed flow depth was approximately 248 inches, which is 13.8 times the pipe diameter, and represents approximately 19.2 feet of surcharging in a MH with a rim to crown depth of 26.2 feet (per the City’s GIS), leaving

7.0 feet of additional headspace. The R-value at this site was –0.292, which indicates frequent backwater conditions. The metering location is just upstream of the Waterloo & Roosevelt PS.

It therefore appears that this pump station is either not keeping up with the incoming flows, or the pump set points are such that the upstream sewers frequently surcharge.

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• Site 4-3: This site is immediately downstream of a flow split, and typically receives less flow than the other flow split outlet (which is captured by Site 4-4). Even though this site is more than a mile upstream of the Waterloo & Roosevelt PS, there is a clear correlation between the flow backups at this site and the more extreme flow backups at Site 4-2. The maximum observed flow depth at this site was approximately 71 inches, which is 7.1 times the pipe diameter and represents approximately 5.1 feet of surcharging in a MH with a rim to crown depth of 16.1 feet (per the City’s GIS) leaving 11.0 feet of additional headspace. The R-value was 0.269, which reflects the fact that this site flowed unimpeded in the absence of severe backups at Site 4-2.
• Site 5-1: This site surcharged during the January 27 and 28 storm event but did not surcharge at any other time. It appears that the surcharge was a combination of backwater and pressure flow conditions given that flow velocities decreased but did not approach zero during the surcharge period. The maximum observed flow depth was approximately 30 inches in a 24-inch diameter pipe and represents approximately 0.5 feet of surcharging in a MH with a rim to crown depth of 12.3 feet (per the City’s GIS) leaving 11.8 feet of additional headspace.
• Site 5-2: As with Site 5-1, this site surcharged during the January 27 and 28 storm event but did not surcharge at any other time. It appears that the surcharge was a combination of backwater and pressure flow conditions given that flow velocities decreased but did not approach zero during the surcharge period. The maximum observed flow depth was approximately 46 inches in a 24-inch diameter pipe and represents approximately 1.8 feet of surcharging in a MH with a rim to crown depth of 14.0 feet (per the City’s GIS) leaving

12.2 feet of additional headspace.
• Site 6-4: This site was the only site that had a negative R-value (–0.027) without ever surcharging. This result indicates that backwater conditions are common, but never enough to generate surcharging at this point in the system.
• Site 6-5: This site surcharged during four different storm events, with a maximum surcharge during the January 27 and 28 storm event, but at no other times. Velocities were relatively low but consistent at the site, thereby indicating backwater flow conditions. The maximum observed flow depth was approximately 71 inches in a 36-inch diameter pipe and represents approximately 2.9 feet of surcharging in a MH with a rim to crown depth of 20.2 feet (per the City’s GIS) leaving 17.3 feet of additional headspace. • Site 10-1: On three different occasions, this site surcharged, and velocities went to zero.

One of these episodes occurred toward the end of the January 27 and 28 storm event, but the other two were not associated with storm events. The maximum observed flow depth was approximately 76 inches (during dry weather conditions), which is 1.4 times the 54-inch pipe diameter, and represents approximately 1.9 feet of surcharging in a MH with a rim to crown depth of 20.7 feet (per the City’s GIS) leaving 18.8 feet of additional headspace. The R-value at this site was – 0.291, which is largely due to the three surcharge episodes. In the absence of these three episodes, a positive correlation exists between depth and velocity.

The metering location is just upstream of the 14-Mile Slough PS. It therefore appears that this pump station shuts off at certain times while flows build up in the upstream sewer, after which time normal pump station operations resume.

ATTACHMENT C
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DRAFT EXHIBIT 1
Chapter 3
Wastewater Flows
N-129-60-20-42-WP-R-WWMP
3-14 City of Stockton
Wastewater Master Plan Update
September 2022

3.5 INVESTIGATION OF FLOW SPLITS
As part of this Master Plan, a special field survey was conducted in September 2020 to evaluate apparent flow splits indicated in the City’s sewer GIS data. A flow split is defined as an MH that has two outlet pipes, and therefore has the potential to direct flows along two separate pathways. The September 2020 field survey supplemented earlier survey work performed in 2018. These surveys either confirmed or refuted the existence of the indicated flow splits, while also providing sewer invert and rim elevation data that has been used to confirm or supplement the City’s sewer GIS data.

In the September 2020 survey, a total of 18 potential flow splits were investigated , involving surveys of 48 MHs either at or downstream of the suspected flow splits. Two other active flow splits in the downtown area were confirmed in 2018. In addition, five force main flow splits are known to exist, although these splits were not included in any field surveys.

The locations of the 18 flow split locations are presented graphically in Appendix B of this report. The field data sheets obtained from the September 2020 field surveys are presented in Appendix C of this report.

As a result of the various surveys and GIS information, the known or suspected flow splits in the system can be categorized as follows:
• Confirmed flow split under normal gravity flow conditions (six cases) • Confirmed force main flow split (five cases)
• Apparent flow split only under peak flow or surcharged conditions (six cases) • Secondary outlet non-existent, blocked, or not found, i.e., flow split not present or unconfirmed (ten cases)
The various locations of these flow splits are summarized on Figure 3-4. In addition, the City’s sewer GIS data indicates that numerous lesser flow splits may exist throughout the collection system. However, for the following reasons, these potential flow splits are not considered to be significant:

1. The suspected split is on a small diameter line and flows entering the split are expected to be minor, thereby having an insignificant effect on the downstream system.

2. The two flow split paths reconverge a short distance downstream of the split.

3. The flow split MH has two outlets and no inlets, which represents a high point in the system.

Accordingly, these lesser flow splits are not shown on Figure 3-4 and are not considered further in this Master Plan.

ATTACHMENT C
DRAFT
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L a s t S a v e d : 6 / 1 5 / 2 0 2 2 1 0 : 1 2 : 4 2 A M N : \ C l i e nt s \ 1 2 9 S t oc kt on\ 6 0 - 2 0 - 4 2 S t oc kt on W W MP \ G I S \ M X D \ W W M P \ C ha p t e r 3 \ F i gu r e 3 - 4 . F l ow S p l i t I nv e s t i ga t i on R e s u l t s . m x d : j s t e i ne r

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ATTACHMENT T C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
4-1 City of Stockton
Wastewater Master Plan Update
September 2022
CHAPTER 4
Collection System Planning, Design, and Performance Criteria The purpose of this chapter is to present planning, design , and performance criteria applicable to the City’s wastewater collection system. These criteria are relevant to the analysis of the existing system, as well as to the assessment of future capacity needs. The criteria presented in this chapter serve as the basis for the recommended CIP presented later in this report. Key topics addressed in this chapter include:
• Existing City Planning and Design Standards
• Planning and Assessment Criteria Used in This Analysis

4.1 EXISTING CITY PLANNING AND DESIGN STANDARDS
The criteria presented in this chapter are considered adjunct to existing City Standards and are not intended to replace or supersede those standards unless specifically stated otherwise. The City Standards exist as Standard Specifications and Standard Drawings for sewer, storm drain, water and street utilities/infrastructure.

The Standard Specifications for sewers address pipe materials, maintenance holes, trenchin g and construction, and related topics. The Standard Drawings include various drawings related to pipe and maintenance hole construction, plus various system criteria that include the following:
• Dry weather flow factors for various land use categories • Calculation of flow peaking factors
• I&I rates
• Design flow calculations
• Pipe slope, diameter, velocity, and Manning’s “n” requirements for pipe sizing • Pump station and force main design requirements
The pipe, pump station, and force main requirements are not being revised as part of the Master Plan and are assumed to remain in effect. The other standards in the above list are subject to reevaluation in this report.

The City’s existing dry weather flow factors for collection system planning and design are summarized in Table 4-1. The values shown in the table are used to calculate Q a. The City Standards also specify the following formulas, where Qa is expressed in units of mgd:

For Qa < 0.5 mgd: PF = 2.29*Qa–0.338
For Qa = 0.5–1.8 mgd: PF = 2.50*Qa–0.216
For Qa > 1.8 mgd: PF = 2.37*Qa–0.124
I&I is calculated by applying a factor of 400 gpd per acre multiplied by the tributary area in acres. The design flow (Qd) is then calculated by applying the PF value to the sum of the Qa and the I&I, as follows:

Qd = PF * (Qa + I&I)

ATTACHMENT T C
DRAFT
DRAFT EXHIBIT 1
Chapter 4
Planning, Design, and Performance Criteria
N-129-60-20-42-WP-R-WWMP
4-2 City of Stockton
Wastewater Master Plan Update
September 2022
Table 4-1 Existing City of Stockton Collection System Flow Factors Category
Planning Values Design Values
gpd/acre gpd/unit gpd/1,000 sq. ft.

Residential
Single-Family 2,100 300 --
Multi-Family 6,800 270 --
Planned Unit Residential Development 3,700 270 --
Commercial
Office 2,400 -- 90
Retail 2,000 -- 80
Eating and Drinking 8,600 -- 500
Wholesale, Storage 800 -- 40
Industrial
Food processing -- Special Special
Light 3,000 -- 150
Heavy (low wastewater) 3,000 -- 150
Heavy (high wastewater) -- Special Special
Schools
Primary 1,800 0 340
Secondary 1,400 0 310
Source: City of Stockton Standard Drawings, Drawing No. S-1, Sanitary Sewer Design Data, 9/27/2016.

The categories shown in Table 4-1 do not align with the land use categories in the City’s General Plan, and therefore cannot be used in conjunction with General Plan land use data to estimate existing and future collection sys tem flows. Moreover, while the flow factors in Table 4-1 may be suitable for design of collection system facilities, they do not reflect current wastewater flow generation trends throughout the City. For the purposes of this Master Plan, it is therefore necessary to develop a set of flow factors for the land use categories identified in the General Plan, as described in the Section 4.2. This Master Plan does not include recommendations for modifying the City Standards shown in Table 4-1, which continue to function as design criteria for sizing of collection system facilities.

4.2 PLANNING AND ASSESSMENT CRITERIA USED IN THIS ANALYSIS Specific issues not addressed in the existing City Standards that need to be considered in this Master Plan include the following:
• Flow Factors for General Plan Land Use Categories
• Modeling of Peak Wet Weather Flow Conditions
• Capacity Assessment of Existing Facilities

ATTACHMENT T C
DRAFT
DRAFT EXHIBIT 1
Chapter 4
Planning, Design, and Performance Criteria
N-129-60-20-42-WP-R-WWMP
4-3 City of Stockton
Wastewater Master Plan Update
September 2022

4.2.1 Flow Factors for General Plan Land Use Categories As described in detail in Chapter 5, winter water demands from February through March 2019 serve as the basis for the development of flow estimates for existing Qa conditions throughout the City. These demands are also used to determine typical wastewater flow generation rates for each General Plan land use category.

Table 4-2 shows flow generation rates by land use category, assuming a 90 percent return to sewer ratio (defined as the wastewater flow divided by the winter water demands). The results are shown both i n terms of flow per acre and flow per parcel. Flow per residential dwelling unit cannot be calculated because the General Plan Land use database does not contain existing and planned future dwelling unit counts.

Nevertheless, it is expected that the flow per parcel estimates can still be estimated for the Low-Density Residential category, which would typically have one dwelling unit per parcel.

The land use-based flow factors in Table 4-2 are grouped into the following categories:
• Residential
• Commercial/Industrial/Institutional
• Downtown
• Other
The Downtown category includes both Residential and Commercial/Industrial/Institutional categories but are separated out with the understanding that land uses in the Downtown area may have different flow generation characteristics when compared to other areas of the City.

Table 4-2 also indicates the variation in the results by presenting “upper average” values for the flow per acre and flow per parcel calculations. This upper average is calculated as being the average of all parcel - specific results that exceed the overall average value for the cate gory. For example, the High -Density Residential category shows an average (mean) unit flow of 2,467 gpd/acre. The average of all values above the mean is 5,772 gpd/acre. This latter value provides some sense of the spread in the individual results.

The following comparisons can be made between the flow generation rates in Table 4-2 and the City flow factors in Table 4-1:

The Low-Density Residential category upper average value of 310 gpd/parcel in Table 4-2 can be compared to the City’s existing Single-Family Residential flow factor of 300 gpd/unit in Table 4-1.

The High-Density Residential category upper average value of 5,772 gpd/acre in Table 4-2 can be compared to the City’s existing Multi-Family Residential flow factor of 6,800 gpd/acre in Table 4-1.

The Administrative Professional upper average value of 3,497 gpd/acre in Table 4-2 can be compared to the City’s existing Office flow factor of 2,400 gpd/acre in Table 4-1.

The Commercial upper average value of 2,988 gpd/acre in Table 4-2 can be compared to the City’s existing Retail flow factor of 2,000 gpd/acre and Eating and Drinking flow factor of 8,600 gpd/acre in Table 4-1.

The Industrial upper average value of 1,846 gpd/acre in Table 4-2 can be compared to the City’s existing Industrial Light and Heavy (low wastewater) flow factors of 3,000 gpd/acre in Table 4-1.

ATTACHMENT T C
DRAFT
DRAFT EXHIBIT 1
Chapter 4
Planning, Design, and Performance Criteria
N-129-60-20-42-WP-R-WWMP
4-4 City of Stockton
Wastewater Master Plan Update
September 2022
Table 4-2 also shows proposed land use -based dry weather flow factors that are rounded off from the upper average values. These factors would be applied to future growth portion of buildout flows in the model, whereas existing conditions dry weather flows will be based on existing water demands, as described in detail in Chapter 5 of this report.

The Industrial flow factor shown in Table 4-2 may require special attention , as i ndustrial flows can be highly industry specific. Many industrial activities (such as warehouses) are extremely low -flow on a per acre basis, while others (such as canneries) are extremely high -flow. Accordingly, while the use of the proposed 2,000 gpd/acre value may be suitable in some situations , higher and/or lower values may be applicable on a case-by-case basis.

Finally, a flow factor for the Economic and Education Enterprise land use category cannot be estimated directly due to a lack of existing development. The only area zoned for this land use is an approximately 3,800-acre area north of Eight Mile Road. For this analysis, it is assumed that the Institutional flow factor would be reasonable approximation for future flow generation for this category.

4.2.2 Modeling of Peak Wet Weather Flow Conditions
The existing City Standards describe how to perform design flow calculations for collection system facilities. The City Standards do not, however, address flow modeling methodologies and assumptions, such as the simulation of peak wet weather flow (Q p) conditions throughout the City’s wastewater collection system. Design flows and peak wet weather flows are similar ; however, whereas design flows are intended for the sizing of new facilities in specific areas of the collection system (such as new areas of development), Qp values are generally derived for locations throughout the collection system. Also, design flows are used to size gravity sewers such that the sewer pipe must not flow more than 100 percent full, whereas some amount of system surcharging may be considered acceptable for Qp conditions.

Surcharging occurs when flow exceeds the open channel flow capacity of a gravity flow pipelin e, which causes the water level in maintenance holes to begin rising above the adjacent pipe crown elevation.

Under surcharged conditions, the pipe flows under pressure and can carry additional flow. Gravity sewers are generally designed to flow partially full, or full without surcharging. However, short periods of surcharging can be accommodated within certain limits without justifying the cost of upsizing an existing pipeline. Such limits are discussed further in Section 4.2.3.

For estimating both design flows and Qp conditions, a Qa condition is established first. For design flows, a peaking factor is derived and a constant rate of I&I is assumed, as described above. For Qp conditions, a hydraulic model is used to apply a diurnal flow pattern to the Qa condition, and then I&I resulting from a simulated severe storm event is superimposed on the dry weather flow pattern. The diurnal flow patterns used in this analysis are described in Chapter 3.

It is common practice to use a 24-hour storm with a 10-year return period as the basis for the simulation of I&I that produces simulated Qp conditions. According to the NOAA, the 10 -year, 24 -hour storm for Stockton has a magnitude of 2.43 inches. The application of the 10-year storm to the collection system is described in Chapter 5.

ATTACHMENT T C
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Table 4-2. Estimate
d Wastewater Flow Generation Rates by General Plan Land Use Category Land Use Parcel Count Area, acres
Average Parcel
Size, acres
Winter Water
Demand, mgd
Return to
Sewer, mgd
Unit Flow by
Area, gpd/acre
Unit Flow by Parcel,
gpd/parcel
Upper Average,
gpd/acre
Upper Average,
gpd/parcel
Proposed Flow
Factor for Future
Growth, gpd/a
cre Notes
Residential 80,724
15,155 0.19 18.334 16.500 1,089 204 -- -- --
High Density Residential 1,379 615 0.45 1.687 1.518 2,467 1,101 5,772 n/a 6,000 Low Density Residential 72,985 13,331 0.18 14.587 13.128 985 180 1,878 310 2,000 City standard = 300 gpd/unit Medium Density Residential 6,360 1,209 0.19 2.059 1.853 1,533 291 3,230 n/a 3,500 Residential Estate 0 0 -- 0 0 -- -- -- -- 2,000 Assumed same as Low Density Res.

P-R-WWMP
City of Sto
ckton
Wastewater Master Plan Update
Last Revised: 04-02-2022

ATTACHMENT T C
DRAFT
DRAFT EXHIBIT 1
Chapter 4
Planning, Design, and Performance Criteria
N-129-60-20-42-WP-R-WWMP
4-6 City of Stockton
Wastewater Master Plan Update
September 2022

4.2.3 Capacity Assessment of Existing Facilities
The following collection system capacity assessment criteria are used in this Master Plan:
• Gravity mains are considered undersized if the criteria presented in Table 4-3 are not met.

Figure 4-1 provides a graphical depiction of the capacity criteria summarized in Table 4-3. • Pump stations are considered undersized if the associated firm capacity (i.e., capacity with the largest pump out of service) is not sufficient at modeled Qp conditions. • Force mains are considered undersized if the maximum velocity exceeds 8 feet per second (fps) at modeled Qp conditions, which is based on commonly used standards in the industry.

A lower maximum velocity may trigger an improvement for very long or large diameter force mains, which will be considered on a case-by-case basis.

In Table 4-3 and Figure 4-1, the hydraulic grade line (HGL) elevation is compared to the ground surface elevation at each MH to assess the severity of surcharging. Surcharging that is predicted to reach an elevation near the ground surface is considered severe and would warrant classification as a high priority (Priority 1) capital improvement under modeled conditions. The nature and location of the improvement will depend on the cause of the surcharging and may not pertain to the same location where severe surcharging is predicted, but instead may be attributable to downstream restrictions.

ATTACHMENT T C
DRAFT
DRAFT EXHIBIT 1
Chapter 4
Planning, Design, and Performance Criteria
N-129-60-20-42-WP-R-WWMP
4-7 City of Stockton
Wastewater Master Plan Update
September 2022
Table 4-3. Existing Gravity Main Capacity Criteria
Capacity Category Criteria (a) Comments
Priority 1 – Possible
Sanitary Sewer Overflows

1. Qp>Qfull; and,

2. HGL within 1 foot of ground surface
These gravity sewers have the
potential to produce sanitary sewer
overflows during peak wet weather
flow events.

Priority 2 – Excessive
Surcharging

1. Qp> Qfull; and,

2. HGL from 1 to 4 feet below ground surface
These gravity sewers have the
potential to backup into service
laterals and drains at low elevations
during peak wet weather flow
events. There is some apparent risk
of overflows.

Priority 3 – Moderate
Surcharging

1. Qp> Qfull; and,

2. HGL from 4 to 8 feet below ground surface
(or)

3. HGL more than 1 foot above crown in sewers
less than 8 feet deep
These gravity sewers have the
potential to backup into service
laterals and drains at low elevations
during severe peak wet weather
flow events. There is reduced
apparent risk of overflows. Field
investigations and flow/surcharge
monitoring is warranted if an
improvement is not otherwise
recommended. Additional flow from
new development is not acceptable
without improvements.

Priority 4 – Minimal
Surcharging/ Reported
Adverse Slope

1.Qp> Qfull; and,

2. HGL more than 8 feet below ground surface
(or)

3. HGL less than 1 foot above crown in sewers
5 to 8 feet deep
(or)

4. Sewer line sloped adversely (negative slope
in the direction of flow)
These sewers have an apparently
acceptable level of peak flow
surcharging. Additional flow from
new development is not acceptable
without capacity improvements.

Sewers with reported adverse
slopes should be field investigated
to verify invert elevations.

Approaching Full-Pipe
Capacity Qp ranges between 90-100% of Qfull;
These sewers do not exceed City
design criteria, but should be
investigated further with flow
monitoring before permitting
additional flows from upstream
development.
(a) “Qfull” is the flow at which no more flow can be accommodated without surcharging.

ATTACHMENT T C
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N-129-60
-20-42-WP-R-WWMP
1 City of St
ockton
Wastewater Master Plan Update
July 2022
Priority 2 Criteria (HG
L 1-4 feet deep)

1. Peak flow exce
eds full-pipe capacity for
gravity flow

2. HGL is between 1–4 feet deep
Priority 4 Criteria

1. Peak flow exce
eds full-pipe capacity for
gravity flow

2. HGL is more than 8 feet deep
Priority 2 Criteria (HG
L 4-8 feet deep)

1. Peak flow exce
eds full-pipe capacity for
gravity flow

2. HGL is between 4–8 feet deep

3. HGL is more than 1 foot above the crown
of the pipe
Priority 3 Criteria

1. Peak flow exce
eds full-pipe capacity
for gravity flow

2. HGL is between 4–8 feet deep

3. HGL  1 foot above the crown of the
pipe
Priority 1 Criteria

1. Peak flow exce
eds full-pipe
capacity for gravity flow

2. HGL is less than 1 foot deep or
flows above the ground surface
(i.e. a potential SSO)
Ground Surface
1 foot deep
4 feet deep
8 feet deep
Notes:

1. Figure Not to Scale

2. SSO means “sanitary sewer
overflow”

3. HGL means “hydraulic grade
line”, the level to which water
would rise in a manhole under
the modeled peak flow
condition.

Figure 4
-1
. Gravity Sewer Capacity Exceedance Criteria
Water Level in MH:

Hyd
raulic Grade Line (HGL)

ATTACHMENT T C
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N-129-60-20-42-WP-R-WWMP
5-1 City of Stockton
Wastewater Master Plan Update
September 2022
CHAPTER 5
Hydraulic Model Development
The purpose of this chapter is to present the development of the hydraulic model of the Stockton wastewater collection system . The hydraulic model described in this chapter and used to support this Master Plan is the most comprehensive collection system model ever developed for the City. Past modeling projects were based on very limited flow and system geometry information, whereas the current model development is based on extensive flow information (as describe d in Chapter 3) and on a detailed analysis of system geometry. The major topics addressed in this chapter include the following:
• Model Construction
• Dry Weather Flow Calibration
• Wet Weather Calibration
• Design Storm Development

5.1 MODEL CONSTRUCTION
The key elements of collection system model construction addressed in this section include the following:
• Modeling Software
• Model Geometry
• Assignment of Parcel-Generated Flows to Model Nodes

5.1.1 Modeling Software
The hydraulic model of the City’s collection system was developed using Innovyze InfoSWMM™ software.

InfoSWMM is a fully dynamic model ing software package that is especially appropriate for the City’s collection due to the existence of flow splits throughout the system that direct flows into multiple pathways. Software that is not fully dynamic is not well -suited for the complex hydraulics of the City’s system because such software cannot reliably simulate the effects of these flow splits.

For purposes of this analysis, InfoSWMM is used to simulate periods of b oth dry and wet weather flow.

The model allows for multiple flow inputs at each node/MH, each of which allows for a diurnal flow pattern to be applied, if appropriate. The following flow input categories are included in the collection system model:
• Residential flows: Diurnal flow pattern
• Industrial flows: Diurnal flow pattern
• Commercial/institutional flows: Diurnal flow pattern
• Groundwater infiltration: Continuous, nonvarying flow pattern • Rainfall-dependent infiltration and inflow (RDII): Storm-dependent flow pattern

5.1.2 Model Geometry
The hydraulic model of the collection system includes all gravity mains of 12 -inch diameter and larger, plus smaller diameter lines that were previously modeled in and around the Downtown area. The hydraulic model also includes a total of 23 pump stations and their associated force mains. The modeled facilities are shown schematically in Figure 5-1.

ATTACHMENT T C
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Figure 5-1
Modeled Collection
System Facilities
C
ity of Stockton
Wastewater Master Plan Update
Last Saved: 6/15/2022 10:16:56 AM N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 5\Figure 5-1. Stockton Wastewater Model Network.mxd : jsteiner [PS
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September 2022
The City maintains a GIS database of its collection system facilities, as described in Chapter 2 of this report.

Included in the GIS pipe data are fields that define the upstream and downstream invert elevations of any given pipe. However, many of the invert elevation values in the database are shown as zero, which indicates that no data exist for these locations. Approximately 40 percent of the pipes in the model have one or both invert elevations missing from the GIS data.

Collection system rim and invert depths and elevations are available from field surveys performed in 2018 as part of previous collection system analyses (total of 39 MHs), and in 2020 under this Master Plan (total of 48 MHs ). Although t hese surveys represent only about 2 percent of the modeled MHs, the data obtained from these surveys are considered reliable and are assumed to supersede the corresponding invert elevation data in the City’s GIS database.

The pipe invert elevations from the City’s collection system GIS do not specify what vertical datum is being used. Comparisons between the surveyed inverts and the City GIS data indicate that the GIS data are consistently in the National Geodetic Vertical Datum of 1929 (NGVD 29), whereas the recent MH surveys used the North American Vertical Datum of 1988 (NAVD 88). In the City , the NAVD 88 datum is approximately 1.91 feet higher than the NGVD 29 datum.

Given the various pipe invert data gaps and datum issues, the following procedure was used to determine invert elevations throughout the modeled portion of the collection system:

1. Invert data from the 2018 and 2020 surveys (collected on the NAVD 88 datum) are considered reliable without adjustment.

2. Non-zero invert data from the City GIS are adjusted by 1.91 feet to account for the difference between the NGVD 29 and NAVD 88 datums.

3. Any datum -adjusted City GIS inverts that are clearly inconsistent with the upstream and downstream inverts are not used.

4. If the upstream end of a pipe exiting a MH has no invert value, but one or more pipes entering the same MH have invert values, the exit pipe invert is assumed to equal the known invert of the largest entering pipe. It is thus assumed that there is no drop through the MH.

5. If a pipe entering a MH has no invert value, but the upstream end of the pipe exiting a MH has an invert value, the entering pipe invert is assumed to be the same as the exit pipe invert.

It is thus assumed that there is no drop through the MH.

6. If the largest diameter pipe inlet and the pipe outlet in a MH have no invert values, the inverts of the inlet and outle t are assumed to equal each other , and those inverts are linearly interpolated between the nearest known/calculated upstream invert elevation and the nearest known/calculated downstream invert elevation, if such invert values exist.

7. If the upstream end of a series of pipe segments has no invert value, or if the downstream end of a series of pipe segments has no invert value before discharging into a pump station, a standard minimum pipe slope value is assumed.

Except where rim elevation data were collected as part of the collection system surveys performed in 2018 and 2020, MH rim elevations used in the model are generally taken from existing LIDAR (Laser Imaging, Detection, and Ranging) data provided by the City. A comparison of the LIDAR results with those of the rim elevation surveys indicates that the LIDAR data generally provide a reasonable approximation of actual rim elevations.

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5.1.3 Assignment of Parcel-Generated Flows to Model Nodes This section describes ho w flows are assigned to the appropriate nodes within the collection system model. As described below in sections 5.2 and 5.3, both dry and wet weather flow inputs are assumed to originate at the parcel level. However, it is not always clear how a given parcel connects to the collection system. Moreover, as noted above, not all collection system pipes are included in the model. Accordingly, it was necessary to develop a methodology for assigning parcels to model nodes and to address complications that were encountered. The issues to be addressed in this process and the actions that were taken to address those issues are summarized below:
• Issue 1: The City’s collection system GIS data does not include private service laterals, so it is not always clear which parcels are actually connected to the collection system.

Action: A GIS proximity analysis was performed wherein any parcel within 300 feet of a sewer MH is assumed to be connected, while any parcel not within 300 feet of a sewer MH is assumed to be unconnected. The proximity analysis involved all sanitary sewer MHs in the City’s GIS whether or not the MH is included in the model. • Issue 2: The collection system model is limited to gravity mains of 12-inch diameter and larger (except for smaller diameter lines that were previously modeled in and around the greater Downtown area).

Action: All unmodeled MHs are assigned to the nearest downstream modeled MH. This process is accomplished by stepping one pipe at a time downstream from each unmodeled MH until a modeled MH is encountered, and then assigning all flows from the upstream unmodeled MHs to the given modeled MH.
• Issue 3: The City’s GIS data does not include collection system facilities in the unincorporated island areas described in Chapter 2.

Action: Flows for the areas known to be connected to the collection system (per Table 2-2 in Chapter 2) are assigned to the nearest model node based on the nearest point of system connection using GIS tools and confirmed through a visual assessment of the GIS data. • Issue 4: Some areas of the City remain on septic tanks even though there are sewer lines in the street.

Action: City staff provided a GIS point file showing active sewer connection locations. Any parcels designated as Low Density Residential with no sewer account were thus assumed to be on septic. This method was not considered a reliable approach for other land use categories because such categories often occupy multiple parcels. For example, a multi- family apartment complex might occupy five different parcels, but only one of those parcels will show a sewer account. In this example, it would not be logical to assume that the other four parcels are on septic.

The process of tracking unmodeled MHs to the nearest downstream modeled MH revealed numerous GIS disparities that needed to be corrected, including:

1. Pipe segments where the upstream and downstream nodes in the pipe designation were reversed.

2. Pipe segments where the upstream node in the pipe designation did not match the designation of the upstream MH.

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3. Pipe segments where the downstream node in the pipe designation did not match the designation of the downstream MH.

4. Pipe segments where an active sewer line was shown to be upstream of an abandoned sewer line or upstream of a planned but not yet constructed sewer line.

5.2 DRY WEATHER FLOW CALIBRATION
Having established the hydraulic model geometry and connectivity, the next step in model development is to calibrate the model to appropriate dry weather flow conditions . The dry weather flow calibration process involves bringing the model dry weather flow generation into conformance with the dry weather flow monitoring results from October and November 2020 that were addressed in Chapter 3 of this report.

The dry weather flow calibration process is complicated by the fact that the collection system flow monitoring program coincided with the pandemic period. The net effect of the pandemic on collection system flows is that flow conditions throughout the City were distorted when compared to pre-pandemic conditions; specifically, residential areas tended to generate higher flows for pandemic conditions than for pre-pandemic conditions, while the reverse was true for many commercial and institutional areas.

Accordingly, some co nsideration of a “pandemic shift” is appropriate when considering baseline dry weather flow conditions. Based on the results presented below, the dry weather model is found to be calibrated to the degree necessary to provide the basis for prudent collectio n system capacity analysis and planning.

With these considerations in mind, the following topics are addressed in this section:
• Dry Weather Flow Generation
• Pandemic Shift Analysis
• Criteria for Dry Weather Flow Calibration
• Diurnal Flow Patterns
• Metered versus Modeled Dry Weather Flows

5.2.1 Dry Weather Flow Generation
The following two distinct methods were considered for the generation of dry weather flows to be used by the hydraulic model for existing development conditions:
• Method 1: Use the dry weather flow monitoring results to generate flow factors for each of the land use categories discussed in Chapter 4 and apply those flow factors to the various land use categories, thus generating modeled baseline dry weather flows. • Method 2: Use winter potable water demands as the basis for the generation of modeled baseline dry weather flows, while applying appropriate adjustments to those demands to bring them into conformance with the dry weather flow monitoring data from October/November 2020.

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For this Master Plan, it was determined that Method 2 likely provides a much more reliable estimate of baseline dry weather flow conditions than Method 1. Specifically, Method 2 accurately captures how flows are distributed throughout the City even within the various land use categories, whereas Method 1 uses a City -wide average flow factor for each land use c ategory and therefore does not account for any variability within those categories.

The use of potable water demands as the basis for collection system dry weather flow conditions does, however, introduce the following complications:

1. In the Central Valley of California, potable water demands most closely match baseline dry weather collection system flows during the winter months of a wet year when outdoor irrigation activities are at a minimum. However, collection system flows most closely represent baseline conditions in the fall prior to the onset of any rains. Therefore, baseline collection system flow and baseline (indoor-only) potable water demands do not occur simultaneously.

2. The most recent period of above average rainfall occurred during the months of February and March 2019, which precedes the pandemic, whereas all of the flow monitoring performed for this Master Plan occurred during pandemic conditions.

The first complication can be addressed by assuming that underlying dry weather baseline flows i n the collection system did not change significantly between February/March 2019 and October/November 2020. The second complication requires an analysis of the effects of the pandemic on water demands.

5.2.2 Pandemic Shift Analysis
As noted above, the effects of the pandemic on collection system flows are dependent on the area of the City under consideration . Specifically, flows from residential areas tended to increase during the pandemic, while flows from commercial and institutional areas tended to decrease. Therefore, the effects of the pandemic shift must be considered separately for each flow metered area under consideration.

Accordingly, the following procedure was used in comparing potable water demands to the collection system flow metering results:

1. February/March 2019 potable water demands from all flow producing parcels are aggregated together for each collection system flow metering area. As noted above, these demands represent a pre-pandemic baseline (minimal outdoor irrigation) condition.

2. October/November 2020 potable water demands from all flow producing parcels are aggregated together for each collection system flow metering area. These demands represent potable water use conditions (indoor and outdoor) coincident with the dry weather collection system flow metering period.

3. October/November 2019 potable water demands from all flow producing parcels are aggregated together for each collection system flow metering area. These demands represent potable water use conditions (indoor and outdoor) that are analogous to the October/November 2020 potable water demand conditions, except that they represent the pre-pandemic period.

4. The difference between the October/November 2020 potable water demands and the October/November 2019 potable water demands is assumed to be solely due to the effects of the pandemic, which assumes that actual irrigation patterns are similar for both periods.

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5. The difference between the October/November 2020 potable water demands and the October/November 2019 potable water demands is added to the February/March 2019 potable water demands to produce an adjusted potable water demand baseline (minimal outdoor irrigation) condition. The result is directly comparable to the October/November 2020 collection system flow metering results.

6. For any given collection system flow metering area, October/November 2020 flow metering result is divided by the adjusted baseline potable water demand just discussed to produce a wintertime return-to-sewer ratio. In general, the expectation is that the wintertime return-to-sewer ratio will be around 90 percent and should fall in the range of 85 to 95 percent, consistent with the findings from similar collection systems throughout the region. Return-to-sewer ratios generally fall below 100 percent due to a combination of wintertime irrigation activities and potable water losses from water distribution system leaks.

7. If the calculated wintertime return to sewer ratio is above 95 percent, it is assumed that such a result is due to the presence of groundwater infiltration. Accordingly, the groundwater infiltration value is calculated to be the measured collection system flow minus 90 percent of the adjusted baseline potable water demand; however, the groundwater infiltration cannot be higher than the low point in the diurnal curve and is thus limited accordingly. The resultant groundwater infiltration value is then distributed equally among all of the modeled MHs in the given flow meter tributary area.

8. If the calculated wintertime return to sewer ratio is below 85 percent, it is assumed that such a result is due to the occurrence of “excess irrigation”, which is assumed to reflect higher rates of irrigation during the February/March 2019 baseline and/or in the difference between October/November 2020 and October/November 2019. Accordingly, the excess infiltration value is calculated to be 90 percent of the adjusted baseline potable water minus the measured collection system flow. This excess irrigation value results in a demand reduction that is applied equally among all of the modeled MHs in the given flow meter tributary area.

The results of applying this methodology are summarized in Table 5-1. The results are limited only to those flow meters that do not have major flow splits upstream of them because the existence of an upstream flow split makes it impossible to define the upstream tributary area. The only exceptions are flow meters 4-3 and 4-4, both of which are immediately downstream of a flow split. Accordingly, the results from these two meters are combined together to represent the tributary area upstream of the flow split.

As indicated in Table 5-1, flow meters 8 -1 and 10 -1 were the only two that had return -to-sewer ratios between 85 and 95 percent. Twelve of the meters showed return-to-sewer ratios above 95 percent, thus indicating the presence of groundwater infiltratio n in the sewer flow monitoring results . The remaining six sites were calculated to have an excess irrigation component in the water demand results.

In addition to the groundwater infiltration results shown in Table 5-1, a further 0.20 mgd of groundwater infiltration was added to model nodes immediately upstream of flow metering site 5-1 to bring the model into conformance with the flow metering results at that location. As a result , the total estimated dry weather groundwater infiltration entering the collection system is estimated to be 2.8 mgd.

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Table 5-1
. Pandemic Shift Analysis Results
Flow
Meter ID
Winter 2019
Wa
ter
Demand, mgd
Oct/Nov 2019
Water
Demand, mgd
Oct/Nov 2020
Water
Demand, mgd
Pandemic
Diffe
rence,
mgd
Adj. Winter
Wa
ter
Demand, mgd
Metered Dry
Weath
er Flow,
mgd
Return-to-
Sewer Ra
tio,
percent
Groundwater
In
filtration,
mgd
Excess
Irrigatio
n, mgd
1-1 0.598 1.737 1.586 -0.151 0.447 0.976 218% 0.574 0
2-1 2.788 4.933 4.843 -0.090 2.698 2.863 106% 0.435 0
2-2 3.776 5.878 6.153 0.275 4.050 3.982 98% 0.336 0
3-1 0.952 1.560 1.827 0.267 1.219 1.023 84% 0 0.070
3-2 1.537 2.262 2.716 0.454 1.991 1.611 81% 0 0.180
3-3 0.209 0.338 0.456 0.118 0.327 0.190 58% 0 0.100
4-1 0.664 0.802 1.052 0.250 0.914 0.566 62% 0 0.260
4-2 0.536 0.877 0.791 -0.086 0.451 0.528 117% 0.122 0
4-3/4-4 0.093 0.149 0.164 0.015 0.107 0.120 112% 0.024 0 6-1 0.338 0.498 0.539 0.041 0.380 0.406 107% 0.064 0
6-2 0.606 0.869 1.097 0.229 0.835 0.633 76% 0 0.120
6-3 1.321 1.829 2.029 0.200 1.520 0.962 63% 0 0
6-4 0.611 0.602 0.842 0.240 0.851 0.547 64% 0 0.220
6-5 0.435 0.613 0.689 0.076 0.511 0.649 127% 0.189 0
7-1 0.534 0.878 1.021 0.143 0.677 1.293 191% 0.501 0
8-1 1.153 1.762 2.102 0.340 1.493 1.351 90% 0 0
8-2 0.322 0.465 0.458 -0.007 0.316 0.403 128% 0.119 0
8-3 0.320 0.236 0.206 -0.029 0.290 0.419 144% 0.157 0
8-4 0.569 0.535 0.488 -0.047 0.521 0.521 100% 0.052 0
10-1 1.983 4.249 4.699 0.451 2.434 2.161 89% 0 0
N-129-60-20-42-WP-R WW
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City of Stockt
on
Wastewater Master Plan Update
Last Revised: 06-09-2022

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5.2.3 Criteria for Dry Weather Flow Calibration
The criteria used for assessing the accuracy of the dry weather flow calibration are taken from the Chartered Institution of Water and Environmental Managemen t (CIWEM) guidelines, which are summarized as follows:
• The volume of modeled versus metered flow should be in the range of ±10-percent. • The modeled versus metered peak flow rate should be in the range of ±10-percent. • The modeled versus metered peak flow depth should be in the range of ±0.5 feet.

In general, for this analysis, the above criteria are viewed as objectives rather than as inviolable standards.

If one or more of these criteria are not met, any such deviation is viewed in terms of whether the model maintains acceptable accuracy while remaining adequately conservative in its predictive capabilities , based on professional judgment.

5.2.4 Diurnal Flow Patterns
In establishing diurnal flow patterns throughout the system, the following procedure was followed:

1. In general, for areas tributary to the flow metering locations with no upstream flow splits, the diurnal flow pattern for all flow -producing parcels within the given area was assumed to follow the observed diurnal dry weather flow patterns at the flow meter for that area.

2. Exceptions were made for flow metering areas in which the observed diurnal flow pattern was significantly distorted by downstream pump station operations (specifically meters 1 -1 and 4-2), as described in Chapter 3. For these areas, diurnal patterns were used from flow metering areas that are nearby and/or have similar land use characteristics.

3. For areas downstream of the flow meters just discussed, diurnal patterns are assigned by land use type, as follows:
a. For residential inputs, use the diurnal pattern from meter 3-3, which has a tributary area that is 99 percent residential.
b. For industrial inputs, use the diurnal pattern from meter 8 -2, which has a tributary area that is 88 percent industrial.
c. For non-residential, non-industrial inputs, use the diurnal pattern from meter 8-3, which has a tributary area that is 77 percent commercial/institutional.

4. If the resultant model diurnal curve has a time lag (due to the effect of long flow travel times), a time offset is applied to the input curve to achieve better agreement between the metered and modeled diurnal flow patterns.

5. If the resultant model diurnal curve is flattened (due to the effect of flow attenuation), an exponential “amplification factor” is applied to the inp ut curve to achieve better agreement between the metered and modeled diurnal flow patterns.

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The metered versus modeled diurnal flow patterns for all 25 metering sites and for the RWC F are presented in Appendix D. In general, very close agreement was achiev ed between the modeled and metered diurnal patterns. Notable disparities include the following:

1. Metering sites 1-1 and 4-2 show significantly different modeled versus metered diurnal patterns. As discussed in Chapter 3, the flow metering pattern is significantly distorted at both of these sites by downstream pump station operations. Specifically, it appears that the Cumberland & Five Mile Creek PS downstream of metering site 1-1 and the Waterloo & Roosevelt PS downstream of metering site 4-2 routinely allow flows to back up into the upstream gravity system, which has the effect of significantly flattening the diurnal flow pattern.

2. Metering sites 4-3 and 4-4, which are located just downstream of the two outlets of a flow split MH, have offsetting disparities where the metered versus modeled combined flow of the two sites almost exactly match. The flows in the two outlet lines are sufficiently low that the individual disparities are not expected to substantially influence peak flow conditions.

3. Metering sites 6-3 and 7-1 show notable differences in magnitude between the modeled and metered flows, as discussed in the next subsection.

4. The modeled diurnal pattern for site 5-2 could not be made to match the metered pattern.

This difference is likely due to the complex effects of various upstream flow splits.

5. The metered diurnal pattern for site 8-4 is very erratic and the model could not be made to match it, although the modeled pattern provides an acceptable approximation.

5.2.5 Metered versus Modeled Dry Weather Flows
In this section, modeled versus metered flows are compared to assess the accuracy of the dry weather calibration and to determine where unexplained disparities exist. Modeled versus met ered average weekday flows for all 25 flow metering areas are compared in Table 5-2, modeled versus metered peak weekday flows are compared in Table 5-3, and modeled versus metered peak flow depths for weekday flow conditions are compared in Table 5-4. As indicated in the three tables, modeled versus metered dry weather flows compare very well for most metering sites. Notable disparities include the following:
• Sites 1-1 and 4-2: As noted in Chapter 3 and in the previous subsection of this chapter, measured peak flows and flow depths at these two locations are distorted by downstream operations of the Cumberland & Five Mile Creek PS and the Waterloo & Roosevelt PS, respectively. However, the modeled versus metered average flows at these sites match to within 2 percent.
• Sites 2-1 and 2-2: As noted in Chapter 3 and in the previous subsection of this chapter, measured peak flows and flow depths at these two locations are distorted by downstream operations of the Swenson PS and the Waterloo & Roosevelt PS, respectively. The modeled versus metered average and peak flows are in conformance with the criteria, but modeled flow depths are well below the metered depths, the latter of which indicates prevalent backwater conditions.
• Site 4-3: Measured flows at site 4-3 (located immediately downstream of a flow split) behave erratically, and the model does not reproduce these flow irregularities. The observed disparities between metered and modeled flow are small enough (0.011 mgd for average flow and 0.019 mgd for peak flow) that they are not expected to significantly distort the downstream results.

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• Site 4-4: The modeled peak flows at this site are slightly more than 10 percent below the metered flows, which essentially offsets the disparity at site 4-3. The peak flow disparity is approximately 0.014 mgd, which is not expected to significantly distort any downstream results.
• Site 6-3: For this site, the model could not be brought into conformance with the observed results. It should be noted that this site is located downstream of sites 4-1 and 4-2, which have measured average dry weather flows that add up to more than the measured average dry weather flow at site 6-3, plus there are additional flows entering the system downstream of sites 4-1 and 4-2 but upstream of site 6-3. A close review of the flow metering data does not give any indication of anomalous measurements at any of these three sites. It is thus possible that an unidentified flow split exists somewhere between sites 4-1 and 4-2 and site 6-3 that is diverting flows into a different part of the system. • Site 6-4: For this site, the modeled versus metered average and peak flows are in conformance with the criteria, but the model predicts average flow depths that are slightly more the

0.5 feet below the metered flow, which suggests either backwater effects the model does not capture or inaccuracies in the system geometry downstream of the flow meter. • Site 7-1: For this site, the model could not be brought into conformance with the observed results. The totality of demands within the 7-1 tributary area was substantially lower than the dry weather flow metering results. Moreover, the low point in the flow metered diurnal curve precluded assuming a high enough amount of groundwater infiltration to bring the model into conformance with the metering results. A close review of the flow metering data does not give any indication of anomalous results. It is thus possible that an unidentified flow split exists somewhere upstream of site 7-1 that is diverting flows from other tributary areas into that part of the system.

5.3 WET WEATHER CALIBRATION
As described in Chapter 3 of this report, the most significant storm event of the 2020/2021 wet season occurred on January 27 –28, 2021, and produced 2.92 inches of rain over 48 hours when averaged over the seven gauges. This storm event p rovides the basis for wet weather calibration of the collection system model.

Based on the results presented below, the model is calibrated to a degree adequate to provide the basis for sound collection system capacity analysis and planning. It should be understood, however, that the collection system response to major storm events may be highly variable, based on such factors as total event rainfall, peak storm intensity, antecedent rainfall, and possibly other factors. It is therefore appropriate in collection system planning to use an adequately conservative design storm condition that considers such uncertainties, as discussed in section 5.4 below. The following t opics are addressed in this section:
• RTK Method
• Criteria for Wet Weather Flow Calibration
• Metered versus Modeled Wet Weather Flows
• Smart Cover Results
• Pump Station Results

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Table 5-2. Metered versus Modeled Average Dry Weather Weekday Flows Flow
Meter ID
Metered Weekday
Flow, mgd
Modeled Weekday
Flow, mgd
Disparity,
mgd
Disparity,
percent
1-1 0.97 0.98 0.010 1.1
2-1 2.87 2.87 0.006 0.2
2-2 3.99 4.00 0.007 0.2
3-1 1.03 1.05 0.022 2.1
3-2 1.62 1.64 0.016 1.0
3-3 0.19 0.20 0.006 3.0
4-1 0.56 0.57 0.005 0.9
4-2 0.53 0.54 0.010 1.8
4-3 0.019 0.030 0.011 46.2
4-4 0.096 0.091 -0.005 -5.5
4-3/4-4 0.12 0.12 0.001 1.2
5-1 1.03 1.03 0.000 0.0
5-2 0.53 0.50 -0.028 -5.5
6-1 0.41 0.41 0.001 0.3
6-2 0.66 0.67 0.016 2.4
6-3 0.95 1.23 0.274 25.1
6-4 0.55 0.54 -0.012 -2.2
6-5 0.65 0.68 0.033 4.9
6-6 1.07 1.10 0.034 3.1
7-1 1.35 1.17 -0.177 -14.0
7-2 3.40 3.61 0.203 5.8
8-1 1.34 1.34 0.001 0.0
8-2 0.46 0.47 0.010 2.2
8-3 0.44 0.45 0.005 1.1
8-4 0.55 0.55 -0.003 -0.5
10-1 2.14 2.20 0.055 2.5
RWCF 24.05 25.99 1.939 7.7%

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Table 5-3. Metered versus Modeled Peak Dry Weather Weekday Flows Flow
Meter ID
Metered Weekday
Flow, mgd
Modeled Weekday
Flow, mgd
Disparity,
mgd
Disparity,
percent
1-1 1.08 1.14 0.058 5.2
2-1 3.53 3.39 -0.149 -4.3
2-2 4.90 4.80 -0.108 -2.2
3-1 1.30 1.42 0.119 8.7
3-2 2.21 2.21 -0.002 -0.1
3-3 0.25 0.25 0.003 1.2
4-1 0.82 0.88 0.054 6.4
4-2 0.62 0.70 0.085 12.9
4-3 0.024 0.043 0.019 55.6
4-4 0.13 0.12 -0.014 -11.8
4-3/4-4 0.16 0.16 0.000 -0.2
5-1 1.26 1.31 0.044 3.4
5-2 0.67 0.72 0.043 6.2
6-1 0.57 0.54 -0.026 -4.7
6-2 0.92 0.91 -0.001 -0.1
6-3 1.37 1.75 0.378 24.3
6-4 0.81 0.79 -0.025 -3.1
6-5 0.83 0.84 0.008 1.0
6-6 1.48 1.50 0.023 1.5
7-1 1.80 1.49 -0.315 -19.1
7-2 4.51 4.58 0.076 1.7
8-1 1.73 1.70 -0.036 -2.1
8-2 0.64 0.66 0.018 2.9
8-3 0.58 0.57 -0.015 -2.6
8-4 0.78 0.71 -0.067 -8.9
10-1 2.77 2.97 0.194 6.8
RWCF 31.05 31.63 0.576 1.8%

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Table 5-4. Metered versus Modeled Peak Dry Weather Flow Depths Flow Meter ID Pipe D, in
Metered Max
Depth, in
Modeled Max
Depth, in Disparity, in
1-1 27 38.7 7.9 -30.8
2-1 48 36.3 14.2 -22.1
2-2 36 28.9 14.7 -14.1
3-1 24 10.4 7.5 -2.9
3-2 30 10.3 9.0 -1.2
3-3 18 3.5 3.7 0.2
4-1 18 6.6 6.1 -0.5
4-2 18 14.9 6.2 -8.7
4-3 10 2.4 1.5 -0.9
4-4 14 3.7 3.3 -0.5
5-1 24 8.0 8.6 0.6
5-2 24 10.4 8.4 -2.1
6-1 24 8.0 4.8 -3.2
6-2 30 9.3 6.6 -2.8
6-3 27 7.8 9.4 1.6
6-4 24 11.8 5.3 -6.5
6-5 36 11.2 6.0 -5.1
6-6 27 7.9 10.3 2.3
7-1 42 10.1 9.2 -0.9
7-2 72 14.1 12.6 -1.4
8-1 48 9.5 7.6 -1.9
8-2 27 9.6 5.1 -4.4
8-3 33 5.3 5.0 -0.3
8-4 42 3.4 4.4 1.0
10-1 54 9.1 9.0 -0.2

5.3.1 RTK Method
This analysis makes use of the RTK method for wet weather calibration of the InfoSWMM model. The RTK parameters are defined as follows:
• R: The portion of total rainfall within the tributary area that enters the collection system in the form of I&I.
• T: The time from the onset of rainfall to the peak of the I&I response. • K: The ratio of the time-to-recession to the time-to-peak of the hydrograph, where the time- to-recession is defined as the time from the peak to the point in time where there is no longer any appreciable I&I response.

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The RTK parameters are derived for each flow -metered area for which applicable peak flow data exist , including areas downst ream of the meters used in the flow monitoring program but upstream of the RWCF. The resultant RTK parameters established through calibration are then applied to the collection system model using the 10 -year, 24 -hour design storm for both existing and buil dout development conditions. RTK values for future development areas are conservatively approximated from those developed in the wet weather calibration process.

5.3.2 Criteria for Wet Weather Flow Calibration
The criteria used for assessing the accuracy of the wet weather flow calibration are taken from CIWEM guidelines noted previously, and are summarized as follows:
• The modeled versus metered peak flow rate should be in the range of –15 percent to +25 percent.
• The volume of modeled versus metered flow during and following the calibration storm should be in the range of –10 percent to +20 percent.
• The modeled versus metered non-surcharged flow depth should be in the range of ±0.5 feet.
• The modeled versus metered depth of surcharge should be in the range –0.5 feet to +1.6 feet.

As with the dry weather calibration, these criteria should be viewed as objectives rather than as inviolable standards. If one or more of these criteria are not met, any such deviation should be viewed in terms of whether the model is a dequately conservative in its predictive capabilities. Of the above criteria, agreement between modeled and metered peak flows is considered the most important criterion, given that peak flows are what define the sizing needs of existing and future collection system facilities.

Major rains came to an end late on the 28 th or early on the 29th, but the effects of rainfall dependent I&I continued for 24 to 48 hours afterward. Accordingly, in assessing the comparison of flow volumes, the 4-day period of January 27–30, 2021 is used for the calculation.

5.3.3 Metered versus Modeled Wet Weather Flows
In this section, modeled versus metered flows are compared to assess the accuracy of the wet weather calibration and to determine where unexplained disparities exist. Modeled versus metered peak flows are compared in Table 5-5, modeled versus metered flow volumes are compared in Table 5-6, and modeled versus metered peak flow depths for weekday flow conditions are compared in Table 5-7. Graphical comparisons of the modeled versus metered wet weather flows are presented in Appendix E. Graphical comparisons of the modeled versus metered wet weather flow depths are presented in Appendix F.

Notable disparities in the wet weather calibration results are summarized as follows:
• Sites 1-1, 2-1, 2-2, 4-2, and 10-1: All of these sites show maximum flow depths well below those that were observed during the flow metering. As noted previously, this result indicates that the various pump station facilities located immediately downstream of these sites did not keep up with the incoming flows during the January 27–28, 2021 storm event, due either to a power failure during the event, or due to operational issues that routinely cause flows to back up into the upstream pipes.

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Table 5-5. Metered versus Modeled Peak Wet Weather Flows Flow
Meter ID
Metered Peak
Flow, mgd
Modeled Peak
Flow, mgd
Disparity,
mgd
Disparity,
percent
1-1 3.03 2.93 -0.10 -3.4
2-1 6.11 5.81 -0.30 -5.0
2-2 7.35 6.97 -0.38 -5.3
3-1 2.12 2.26 0.15 6.6
3-2 4.22 3.90 -0.32 -7.9
3-3 0.49 0.48 -0.01 -2.2
4-1 1.85 1.90 0.05 2.8
4-2 1.42 1.60 0.17 11.6
4-3 0.39 0.22 -0.17 -54.3
4-4 0.24 0.30 0.06 23.2
4-3/4-4 0.57 0.53 -0.05 -8.7
5-1 2.69 2.49 -0.21 -8.1
5-2 1.59 1.39 -0.20 -13.6
6-1 0.91 0.94 0.03 2.9
6-2 3.46 3.29 -0.17 -4.9
6-3 3.11 3.91 0.80 22.9
6-4 2.75 2.96 0.21 7.2
6-5 3.75 4.13 0.38 9.7
6-6 3.95 3.61 -0.34 -8.9
7-1 3.59 3.53 -0.05 -1.5
7-2 8.04 7.88 -0.16 -2.0
8-1 2.54 2.34 -0.20 -8.0
8-2 1.06 0.97 -0.09 -8.9
8-3 0.80 0.70 -0.11 -14.1
8-4 1.14 1.07 -0.08 -7.0
10-1 3.43 3.39 -0.04 -1.2
RWCF 55.35 56.43 1.08 1.9%

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Table 5-6. Metered versus Modeled Wet Weather Flow Volumes Flow
Meter ID
Metered Flow
Volume, Mgal
Modeled Flow
Volume, Mgal
Disparity,
Mgal
Disparity,
percent
1-1 4.67 5.01 0.35 7.1
2-1 14.00 14.27 0.27 1.9
2-2 18.09 18.37 0.28 1.5
3-1 4.70 5.11 0.41 8.3
3-2 7.25 7.94 0.69 9.1
3-3 1.14 1.12 -0.02 -2.0
4-1 2.86 2.99 0.13 4.6
4-2 2.65 2.93 0.29 10.3
4-3 0.48 0.37 -0.11 -25.8
4-4 0.33 0.44 0.11 28.3
4-3/4-4 0.82 0.81 0.00 -0.2
5-1 6.00 5.22 -0.78 -14.0
5-2 3.15 3.08 -0.07 -2.3
6-1 1.93 2.03 0.10 4.9
6-2 3.83 4.26 0.43 10.5
6-3 5.03 6.81 1.78 30.1
6-4 3.07 3.33 0.25 7.9
6-5 4.74 5.31 0.58 11.5
6-6 5.39 5.88 0.49 8.8
7-1 7.41 6.79 -0.62 -8.7
7-2 18.03 18.38 0.35 1.9
8-1 6.03 6.01 -0.02 -0.3
8-2 2.23 2.09 -0.14 -6.4
8-3 1.95 1.93 -0.02 -1.1
8-4 2.38 2.48 0.10 3.9
10-1 7.90 9.46 1.55 17.9
RWCF 126.64 134.51 7.87 6.0%

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Table 5-7. Metered versus Modeled Peak Wet Weather Flow Depths Flow
Meter ID
Pipe
Diameter, in
Metered
Flow
Depth, in
Modeled
Flow
Depth, in
Disparity,
in
Meter
d/D
Model
d/D
1-1 27 54.0 24.1 -29.9 2.00 0.89
2-1 48 84.0 21.6 -62.5 1.75 0.45
2-2 36 79.5 21.4 -58.2 2.21 0.59
3-1 24 13.5 10.5 -3.0 0.56 0.44
3-2 30 14.8 13.8 -1.0 0.49 0.46
3-3 18 8.1 5.9 -2.2 0.45 0.33
4-1 18 12.5 11.1 -1.4 0.69 0.62
4-2 18 40.2 11.1 -29.1 2.23 0.62
4-3 10 7.3 4.0 -3.4 0.73 0.40
4-4 14 8.8 6.2 -2.6 0.63 0.44
5-1 24 29.5 13.2 -16.3 1.23 0.55
5-2 24 45.9 13.1 -32.8 1.91 0.55
6-1 24 17.2 7.2 -10.1 0.72 0.30
6-2 30 18.8 13.8 -5.0 0.63 0.46
6-3 27 14.1 16.9 2.8 0.52 0.63
6-4 24 16.8 10.5 -6.3 0.70 0.44
6-5 36 70.6 16.1 -54.5 1.96 0.45
6-6 27 13.5 18.8 5.3 0.50 0.70
7-1 42 17.7 15.7 -2.0 0.42 0.37
7-2 72 20.2 18.2 -2.0 0.28 0.25
8-1 48 12.0 10.2 -1.8 0.25 0.21
8-2 27 11.0 7.1 -3.9 0.41 0.26
8-3 33 6.7 6.6 -0.1 0.20 0.20
8-4 42 4.9 6.1 1.2 0.12 0.14
10-1 54 61.7 10.9 -50.8 1.14 0.20

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• Sites 4-3 and 4-4: The model was unable to reproduce the behavior of the flow split upstream from these two sites. The model directs too much flow down the site 4-3 route in dry weather and not enough in wet weather. For purposes of this analysis, it was determined that the metered peak wet weather flow at site 4-3 (0.39 mgd) was small enough relative to the full-pipe capacity of that line (0.70 mgd) that there is no expectation this line will reach its full-pipe capacity under peak wet weather conditions. • Sites 5-1, 5-2, and 6-5: These sites, which are located toward the downstream end of the system, all surcharged during the January 27–28, 2021 storm event, whereas the model does not reproduce such surcharging. City staff have indicated that chronic grease and debris accumulation occurs in various lines downstream of these meters due to substandard or adverse pipe slopes, thus resulting in system flow restrictions. In addition, the model moderately underpredicts flow volume; however, this disparity is considered an acceptable deviation provided the peak flows meet the criteria.
• Sites 6-1 and 6-4: These sites show greater flow depths than indicated in the model, although neither of them surcharged during the January 27–28, 2021 storm event. The disparities may be attributable to a combination of imperfect pipe invert information (i.e., flatter actual pipe slopes than those in the model) or to the effects of backwater further downstream, which affected sites 5-1, 5-2, and 6-5, as just noted. • Site 6-3: This site meets the requisite peak flow and flow depth criteria, but the model generates approximately 30 percent more total volume than was observed at the flow meter. As noted above in the dry weather calibration results, questions exist about this site because it includes the flows from sites 4-1 and 4-2, but the dry weather flows for site 6-3 added up to less than the sum of the flows from those two sites. For purposes of this analysis, the excessive volume at site 6-3 is considered an acceptable deviation provided the peak flows meet the criteria.
• Site 10-1: The site could not be brought into conformance with the criterion for flow volume.

However, t site is located just upstream of a pump station (14-Mile Slough) that stopped pumping during the later period of the storm. Eventually, the backed-up flows were drawn down, but it appears that the velocities were lower than the detection limits of the flow meter. Therefore, the flow meter likely under-reported flow volumes during the drawdown period, which suggests that the model is actually in line with the true flow volumes.

5.3.4 Smart Cover Results
The City deploys SmartCover™ devices at multiple locations throughout the City . A SmartCover is an ultrasonic water level sensing device installed within a MH to measure flow depths. For this study, City staff provided SmartCover results for 22 collection system locations, as summarized in Table 5-8. The table shows the street address closest to the MH, the system number, the pipe diameter, the maximum depth of flow during the January 27 –28, 2021 storm (if available), the MH ID number, and whether the sewer line in question is included in the modeled portion of the collection system.

As indicated in Table 5-8, all but four of the SmartCover devices are located in Systems 2 and 3, and all but six of them are on smaller diameter lines that are not included in the collection system model. Seven sites either had bad data (negative depths) or no data at all during the January 27–28, 2021 storm event.

Two other devices reported results in inches below the sensor without a clear indication of the sensor height, thus making it impossible to assess flow depth, although neither device indicated wet weather results substantially different from those obtained during dry weather.

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Table 5-8. SmartCover Results, January 27–28, 2021
Address System Pipe D, in MH ID Maximum Depth, in(a)
Modeled
Line?
7102 Richland Way 1 10 22F055 21.7 no
105 Edan Avenue 2 6 21K159 bad data (<0) no
238 Lincoln Court 2 6 22K050 no storm data no
405 Pardee Lane 2 15 26K018 29.0 YES
417 Jill Circle 2 8 21L007 8.4 no
4550 Shelley Court 2 6 26L023 6.0 no
4703 Greensboro Way 2 10 25M049 2.9 no
6410 Kermit Lane 2 6 22L062 no storm data no
6808 Villa Drive 2 6 22L010 bad data (<0) no
7011 Leesburg Place 2 6 22H105 no storm data no
Carnelian Drive and
Pleasant Court 2 10 23M038 5.1 no
Hammer Lane and
Albany Drive 2 33 21L096 66.1 YES
March Lane and
Palm Plaza 2 15 24M148 26 (into deadband) YES
1205 Brookside Road 3 8 28J007 11.6 below sensor (depth unclear) no 1440 N. Hunter Street 3 6 30M096 3.0 no
1810 Allston Way 3 6 30L120 bad data (<0) no
2204 Kensington Way 3 16 30L109 18.6 YES
4404 Manchester Avenue 3 8 27K065 13.7 below sensor (depth unclear) no Brookside Road and
Crown Avenue 3 18 28J016 no storm data YES
9007 Sherill Court 5 8 18H067 3.8 no
S. American Street and
E. 8th Street 6 8 37P058 7.9 no
2203 Georgia Avenue 7 12 38L053 0.8 YES
(a) Yellow highlighting denotes evidence of surcharging.

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A total of five SmartCover devices show indications of system surcharging during the January 27–28, 2021 storm event. The results and the possible causes are summarized as follows:

1. The device at 7102 Richland Way in System 1 measured a depth of 21.7 inches, thus surcharging to 11.7 inches above the crown of the 10-inch diameter pipe. The model does not show capacity restrictions in the area, but the site is located a short distance upstream of the Plymouth & 5-Mile Creek PS, which may have undergone a power failure during the storm. Moreover, the SmartCover data indicate that this site routinely surcharges, even during dry weather conditions, thus suggesting that the pump station setpoints allow flows to back up into the upstream gravity system.

2. The device at 405 Pardee Lane in System 2 measured a depth of 29.0 inches, thus surcharging to 14 inches above the crown of the 15-inch diameter pipe. The model does not show capacity restrictions in the area; however, the data indicate that this line routinely surcharges to a similar degree during dry weather as well. The MH in question is located upstream of the Swenson PS, which has been shown not to keep up with incoming flows during both wet and dry weather flow conditions.

3. The device at Hammer Lane and Albany Drive in System 2 measured a depth of 66 inches, thus surcharging to 33 inches above the crown of the 33-inch diameter pipe and routinely shows surcharged or near-surcharged conditions during dry weather flow conditions. The MH in question is located upstream of the Swenson PS, which has a rated firm capacity well above the predicted flows, but has been shown to allow flow to rise above the incoming sewer during both wet and dry weather flow conditions.

4. The device at March Lane and Palm Plaza in System 1 measured a depth of more than 26 inches (which entered the deadband of the device), thus surcharging to at least 11 inches above the crown of the 15-inch diameter pipe. The model does not show capacity restrictions in the area, but the site is located a short distance upstream of the Camanche & Ridgeway PS, which may have undergone a power failure during the storm.

5. The device at 2204 Kensington Way in System 3 measured a depth of 18.6 inches, thus surcharging to 2.6 inches above the crown of the 16-inch diameter pipe. The model confirms minor capacity restrictions and surcharging in this line for peak wet weather flow conditions.

5.3.5 Pump Station Results
The modeled pump station peak flow results for the January 27–28, 2021 storm event are summarized in Table 5-9. The information includes pump station firm capacity (as presented in Chapter 2 of this report), modeled peak flows, dry weather average flows, peaking factors (defined as the peak flow divided by the dry weather average flow), force main diameters, and calculated maximum force main velocities.

For the calibration storm condition, a slight exceedance of pump station firm capacity is indicated at the Don Avenue & Santiago PS, but not at any other pump stations. The maximum force main velocity criterion of 8 feet per second (discussed in Chapter 4 of this report) is not exceeded at any pump stations, and 14 of the 23 pump stations show maximum force main velocities of less than 2 feet per second.

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Table
5-9. Modeled Pump Station Results, January 27–28, 2021 Calibration Storm Lift Statio
n System
Firm
Capacity
, mgd
Dry Weath
er Average
Flow, mgd
Peak Flow,
mgd
Peaking
Factor
Force Main

Diameter, in
Max Force Ma
in
Velocity,
ft/sec
14-Mile Slough 10 (a) 3.87 7.96 2.1 30 2.5
Alexandria
& 14-Mile 2 1.97 0.37 0.87 2.4 15 1.1
Arch 8 8.70 0.20 0.48 2.3 24 0.2
Blossom Ranch 2 1.30 0.22 0.39 1.7 8 1.7
Brookside Estates 10 8.64 0.42 1.61 3.8 20 1.1
Camanche & Ridgeway 2 2.40 0.36 0.68 1.9 none --
County Hospital -- 2.16 0.014 0.12 8.7 dual 10 0.2
Cumberland & 5-Mile 1 4.32 1.17 3.14 2.7 16 3.5
Don Ave & Santiago 2 0.79 0.41 0.90 2.2 15 1.1
Drake & Hwy-99 4 3.54 0.55 1.91 3.5 14 2.8
Grupe 7 0.86 0.008 0.037 4.6 8 0.2
Kelly & Mosher 1 4.32 0.51 1.21 2.4 12 2.4
March-Brookside 2 1.15 0.30 0.57 1.9 8 2.5
Origone 9 5.18 0 0 -- 16 0
Plymouth & 5-Mile 1 1.25 0.16 0.34 2.2 8 1.5
Sanguinetti 9 15.98 0.086 0.18 2.1 24 0.1
Sinclair & Hwy-4 7 4.32 0.033 0.094 2.8 6 0.7
Smith Canal & Fontana 3 37.92 10.38 13.08 1.3 dual 30 2.1 Swenson (North) 2 20.16 7.14 7.14 1.0 dual 24 1.8
Thornton & Davis 2 1.22 0.53 0.96 1.8 8 4.3
Waterloo & Roosevelt 4 2.74 0.61 1.73 2.8 12 3.4
Westlake 10 4.35 0.016 0.025 1.6 8 0.1
Weston Ranch 8 15.98 1.29 1.12 0.9 dual 30 0.2
(a) Firm capacity
not known; see Table 2-9.

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City of Stoc
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Last Revised: 06-09-2022

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5.4 DESIGN STORM DEVELOPMENT
As noted in Chapter 4 of this report, the 1 0-year, 24 -hour storm in Stockton has a magnitude of

2.43 inches. The rainfall distribution pattern used for this analysis is consistent with that being used in ongoing storm water master planning being performed by the City. Specifically, stormwater master planning analyses make use of a 10 -year, 24-hour design storm pattern based on the NOAA California Type III distribution. A plot of that distribution is shown on Figure 5-2.

Figure 5-2. NOAA Type III Rainfall Distribution, City of Stockton 10-Year Storm, 24-Hour Storm It is expected that for existing development conditions, the modeled 10-year, 24-hour design storm should produce peak flows at the RWCF that are consistent with historical results. Table 5-10 shows the top ten daily influent flow totals at the RWCF since the 2010/2011 wet season (11 years total), as taken from the California Integrated Water Quality System Project (CIWQS). As indicated in the table, the high daily flow total of 53.3 mgd occurred on J anuary 10, 2017. This total contrasts with a CIWQS -reported daily flow total of 38.7 mgd on January 28, 2021 (also shown in Table 5-9), which was the highest of the 2020/2021 wet season.

A review of 5 -minute influent flow data provided by City staff indicates that the highest instantaneous flow during the period of 2011 to 2021 occurred on December 2, 2012 and on January 10, 2017 (coinciding with the two highest daily flow totals), when influent flows reached a peak of 73.6 mgd on both occasions.

The January 10, 2017 flow plateaued at the peak value for nearly four hours, a s shown on Figure 5-3, whereas no such plateau occurred on December 2, 2012. The January 10, 2017 peak flow plateau indicates either that the RWCF influ ent pumping reached its hydraulic limit, which did not allow any additional flows to enter the plant, or that the limits of the flow measuring device were reached. In either case, the actual peak flows were likely higher than indicated. Because the flows in question represent the highest in the past eleven wet seasons, it is reasonable to suppose that for a 10-year, 24-hour storm event, peak influent flows at the RWCF would likely be on the order of 80 mgd or higher. The modeled peak wet weather flows for existing development conditions are presented in Chapter 6 of this report. 0 0.02

0.04 0.06

0.08 0.1

0.12 0.14

0.16 0.18

0.2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Rainfall, inches/0.1-hour interval
Elapsed Time, hours

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Table 5-10. Top Ten RWCF Influent Daily Flow Totals, 2011–2021 Rank Daily Flow Total, mgd(a) Peak Hour Flow, mgd Date of Occurrence 1 53.3 73.6 1/10/2017
2 52.3 73.6 12/2/2012
3 51.3 63.8 2/20/2017
4 48.3 65.4 12/12/2014
5 47.9 67.4 2/10/2017
6 45.4 not requested 2/13/2019
7 44.9 not requested 11/30/2012
8 44.3 54.4 2/9/2017
9 44.1 54.3 2/21/2017
10 44.0 60.0 1/22/2017
Calibration Storm 38.7 55.4 1/28/2021
(a) Source: CIWQS

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0 10
20 30
40 50
60 70
80 1/10/2017 12:
00 1/10/2017 18:00 1/11/2017 0:00 1/11/2017 6:00 1/11/2017 12:00 Flow R
ate, mgd
Figure
5-3. RWCF Influent Flows, January 10–11, 2017

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CHAPTER 6
Analysis of Existing Flow Conditions
The purpose of this chapter is to present the results of the hydraulic model of the Stockton wastewater collection system for existing development conditions and to present recommended actions to address existing system deficiencies. The major sections of this chapter include:
• Model Results for Existing Conditions
• Modeled Capacity Deficiencies
• Improvements to Address Existing Capacity Deficiencies • Previously Identified System Condition Deficiencies

6.1 MODEL RESULTS FOR EXISTING CONDITIONS
Model results for existing conditions at the RWCF and at the 25 collection system flow metering sites are summarized in Table 6-1. The table shows modeled weekday dry weather average flows, modeled peak flows from the January 27–28, 2021 calibration storm, and modeled peak flows from the 10-year, 24-hour design storm described in Chapter 5. The peaking factors for the January 27–28, 2021 calibration storm and the 10-year, 24-hour design storm flow condition (defined as the peak flow divided by the modeled dry weather average flow ) are also shown. Because flow meters 4 -3 and 4 -4 are located immediately downstream of a flow split, those results are shown both together and separately, as discussed in Chapters 3 and 5.

As shown in Table 6-1, the model indicates a peak flow of 78.48 mgd at the RWCF for the 10-year, 24-hour design storm, which is consistent with available RWCF influent data from the past 11 years, as discussed in Chapter 5. The peaking factor associated with this result is 2.9. Nine of the flow metering locations indicate peaking factors below the RWCF value of 2.9, and 16 meters indicate peaking factors above the RWCF value . In general, the lowest peaking factors are associated with the northernmost and southernmost areas of the City (predominantly Systems 2, 8, and 10), while the highest peaking factors are associated with Systems 4 and 6.

Peak flow results for the 10-year, 24-hour design storm at the 23 modeled pump stations are summarized in Table 6-2. The information includes pump station firm capacity (as presented in Chapter 2 of this report), modeled peak flows, force ma in diameters, and calculated maximum force main velocities. For purposes other than the calibration modeling, the model treats pump stations as passing all incoming flows regardless of station capacity such that the capacities of the pump stations and downstream gravity lines can be properly evaluated.

For the 10-year, 24-hour design storm condition, exceedances of pump station firm capacity are indicated at two pump stations: the Cumberland & 5-Mile Creek PS and the Don Avenue & Santiago PS. The maximum force main velocity criterion of 8 fps (discussed in Chapter 4 of this report) is not exceeded at any pump stations. The highest indicated force main velocity is 6.3 fps at the Cumberland & 5-Mile Creek PS. In addition, 11 of the 23 modeled pump stations show maximum force main velocities of less than 2 fps.

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6-2 City of Stockton
Wastewater Master Plan Update
September 2022
Table 6-1. Modeled Average and Peak Flows for Existing Development Conditions Flow
Meter ID
Modeled Flows, mgd Peaking Factors
Weekday Dry
Weather Average
January 27–28,
2021 Peak
10-Year, 24-Hour
Design Storm Peak
January 27–28,
2021 Peak
10-Year, 24-Hour
Design Storm Peak
1-1 0.98 2.89 6.10 2.9 6.2
2-1 2.79 5.50 7.47 2.0 2.7
2-2 4.06 7.26 8.45 1.8 2.1
3-1 1.05 2.26 3.13 2.2 3.0
3-2 1.64 3.90 5.55 2.4 3.4
3-3 0.20 0.48 0.69 2.4 3.5
4-1 0.57 1.90 3.20 3.4 5.7
4-2 0.57 1.60 2.36 2.8 4.2
4-3 0.059 0.22 0.31 3.8 5.3
4-4 0.061 0.30 0.44 5.0 7.3
4-3/4-4 0.12 0.53 0.75 4.4 6.3
5-1 1.00 3.23 3.44 3.2 3.4
5-2 0.58 1.45 2.34 2.5 4.0
6-1 0.41 0.94 1.00 2.3 2.4
6-2 0.64 3.32 5.54 5.1 8.6
6-3 1.25 3.91 6.10 3.1 4.9
6-4 0.54 2.96 5.83 5.5 10.9
6-5 0.68 4.07 8.05 6.0 11.8
6-6 1.05 3.64 6.07 3.5 5.8
7-1 1.17 3.53 4.44 3.0 3.8
7-2 3.82 7.86 9.48 2.1 2.5
8-1 1.34 2.34 2.53 1.7 1.9
8-2 0.47 0.97 1.19 2.1 2.6
8-3 0.45 0.70 0.83 1.6 1.9
8-4 0.55 1.07 1.21 1.9 2.2
10-1 2.20 3.39 3.93 1.5 1.8
RWCF 27.20 56.02 78.48 2.1 2.9

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 6-2
. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, Existing Development Conditions Pump Statio
n System
Firm
Capacity, mgd
Peak
Flow, mgd (a)
Force Main
Diameter, in
Ma
ximum Force Main
Velocity, ft/sec
14-Mile Slough 10 (b) 10.59 30 3.3
Alexandria &
14-Mile Slough 2 1.97 1.21 15 1.5
Arch Road 8 8.70 0.55 24 0.3
Blossom Ranch 2 1.30 0.48 8 2.1
Brookside Estates 10 8.64 2.62 20 1.9
Camanche & Ridgeway 2 2.40 0.87 none --
County Hospital -- 2.16 0.19 dual 10 0.3
Cumberland & 5-Mile Creek 1 4.32 5.73 16 6.3
Don Ave & Santiago 2 0.79 1.31 15 1.7
Drake & Highway 99 4 3.54 3.18 14 4.6
Grupe Business Park 7 0.86 0.036 8 0.2
Kelly & Mosher Slough 1 4.32 1.77 12 3.5
March-Brookside & I-5 2 1.15 0.76 8 3.4
Origone 9 5.18 0.001 16 0.0
Plymouth & 5-Mile Creek 1 1.25 0.49 8 2.2
Sanguinetti 9 15.98 0.24 24 0.1
Sinclair Avenue & Highway 4 7 4.32 0.123 10 0.3
Smith Canal & Fontana 3 37.92 31.34 dual 30 4.9
Swenson (North) 2 20.16 18.42 dual 24 4.5
Thornton & Davis 2 1.22 1.18 8 5.2
Waterloo & Roosevelt 4 2.74 2.59 12 5.1
Weston Ranch 8 15.98 2.60 dual 30 0.4
(a) Exceedances of pump station firm c
apacity and the force main velocity criterion of 8 ft/sec are highlighted in yellow. (b) Cannot be calculated due
to unknown pump capacities; see Table 2-9.

N-129-60-20-42-WP-R-WW
MP
City of Stockt
on
Wastewater Master Plan Update
Last Revised: 06-10-22

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 6
Analysis of Existing Flow Conditions
N-129-60-20-42-WP-R-WWMP
6-4 City of Stockton
Wastewater Master Plan Update
September 2022

6.2 MODELED CAPACITY DEFICIENCIES
A schematic of modeled gravity sewer and pump station capacity deficiencies for 10-year, 24-hour design storm conditions is presented in Figure 6-1. The highlighted gravity lines are shown as belonging to the following categories, which are based on the standards presented in Chapter 4 of this report:
• Priority 1 – Near-Surface Surcharging: Peak flow exceeds full-pipe capacity, with a risk of sanitary sewer overflow (SSO) or surcharging to within 1 foot of the MH rim • Priority 2 – Significant Surcharging with Lower SSO Risk: Peak flow exceeds full-pipe capacity, with surcharging to within 1 to 4 feet of the MH rim or to within 4 to 8 feet of the MH rim when surcharging exceeds 1 foot above the pipe crown • Priority 3 – Minor Surcharging in Shallow Sewers: Peak flow exceeds full-pipe capacity, with surcharging to within 4 to 8 feet of the MH rim when surcharging is less than 1 foot above the pipe crown
• Priority 4 – Other Minor Surcharging: Peak flow exceeds full-pipe capacity, with surcharging that is not within 8 feet of the MH rim
• Backwater-Induced SSO (trigger for high priority improvements downstream): Peak flow does not exceed full-pipe capacity, but downstream restrictions result in an upstream SSO or surcharging to within 1 foot of the MH rim
• Backwater-Induced Surcharging (trigger for lower priority improvements downstream):

Peak flow does not exceed full-pipe capacity, but downstream restrictions result in surcharging that is not within 1 foot of the MH rim
• Sewer Pipe Flowing >80% Full: Peak flow exceeds 80 percent of full-pipe capacity with no significant surcharging

6.3 IMPROVEMENTS TO ADDRESS EXISTING CAPACITY DEFICIENCIES Theoretical pipe upsizing improvements to eliminate gravity sewer capacity deficiencies are listed in Table 6-3 and are shown schematically in Figure 6-2. As indicated in the table, improvements are grouped by priority, with Priority 3 and 4 improvements combined in a single category. The improvements are sized to accommodate modeled buildout peak flow conditions.

It should be noted that these theoretical improvements do not necessarily equate to a recommendation to proceed forward with design and construction of replacement sewers. While the model indicates potential for surcharging and/or SSO s in the indicated lines during peak flow conditions, most of the identified pipes were not directly flow metered, but rather the peak flows are inferred from downstream flow measurements based on the model calibration process described in Chapter 5 of thi s report.

Moreover, the collection system geometry (especially pipe diameters, pipe invert elevations, and surface elevations) have not generally been confirmed by field surveys.

Notes and recommendations for the deficiencies identified in Table 6-3 are presented in Table 6-4. In all cases, system geometry (including pipe depths, diameters, and rim elevations) should be confirmed by field surveys. In addition, it is recommended that the City install flow depth monitoring devices to monitor for possible surcharging at the locations indicated in Table 6-4. It is also recommended that the modeled capacity exceedances at the Cumberland & 5 -Mile Creek PS and the Don Avenue & Santiago PS be confirmed through flow metering and/or pump run time logging.

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W E S T L N

P O R T O F

S T O C K T O N E Y

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R D
Figure 6-1
Modeled Capacity Deficiencies
10-Year, 24-Hour Storm
Existing Development Conditions
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 6\Figure 6-1. Existing 10yr24hr Capacity.mxd - jsteiner - 7/15/2022 Modeled Sewer Lines
1 2
3 4
10 8
7 9
6 5
10 8
1-10 Collection System Service Areas
Priority 1
Priority 2
Priority 3&4
Backwater-Induced SSO
Backwater-Induced Surcharging
>80% Full, No Surcharging
<80% Full, No Surcharging
Force Main
TF C W RU Regional Wastewater Control Facility
[PS
±Pump Station - No Capacity Deficiency
[PS
±Pump Station - Capacity Deficiency

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 6-3. Theo
retical Upsizing Improvements That Would Alleviate Existing Capacity Deficiencies ID # Desig
nation Priorities System
GIS Year
Constructed
Upstream
MH ID
Upstream
MH Location
Downstream
MH ID
Downstream
MH Location
GIS Pipe
Dia, in
Upsized
Pipe Dia, in
Total
Length, ft
No. of Pipe
Segments
Depth to Pipe
Crown, ft
Maximum
Flow, mgd
Maximum
Surcharge, ft
Minimum
Headspace, ft
Priority 1 Group
1-1 E. Marsh Street sewer 1,2,4 6 1895–1940 32R072 Olympic Circle 33P105 S. Sierra Nevada Street 18 24 7,406 21 4.0 to 10.4 4.04 5.1 0 1-2 El Dorado Street /
S. Center Street sewer 1,2,4 6 1905–1915 37N043 E. 6th Street 36M016 E. Charter Way 16 21,24 2,832 9 10.5 to 12.1 3.54 8.9 0.4 1-3 S. Wilson Way sewer 1,2 6 1947 34P082 E. Worth Street 35P012 Mormon Slough 10,12 21 1,001 5 7.6 to 8.6 2.73 8.1 0 1-4 E. 6th Street sewer 1,2 6 1900 37N034 S. San Joaquin Street 37N043 El Dorado Street 12 18 701 4 10.2 to 10.8 1.89 10.7 0 Priority 2 Group
2-1 E. Main Street sewer 2,4 6 1910–1984 33S033 Anteros Avenue 33Q014 E. Washington Street 12,16 18 7,605 24 7.6 to 10.3 1.74 6.1 2.1 2-2 W. Washington Street /
Port Road 23 sewer 2 5 no data 34J016 west of Port Road 13 36H003 north of Navy Drive 12,15,18 18,21 3,800 9 5.6 to 11.8 2.92 4.9 4.0 2-3 Don Avenue /
Meadow Avenue sewer 2 2 1957–1973 20G060 Santiago Way 21G051 Oak Creek Drive 12 15 2,171 10 8.1 to 9.8 1.44 3.7 4.6 2-4 S. El Dorado Street sewer 2,4 6 1900–1910 35N064 E. Worth Street 36N016 E. Charter Way 12 15 2,184 6 8.9 to 11.5 1.13 1.8 7.1 Priority 3&4 Group
4-1 Market Street sewer 4 5 1900–1920 33M079 S. El Dorado Street 34L002 S. Lincoln Street 16,18 27 2,320 8 11.5 to 16.1 1.82 2.0 11.6 4-2 Church Street /
Pershing Avenue sewer 4 5,6 1917 34L022 S. Harrison Street 35L027 S. Pershing Avenue 24 30 3,992 11 9.8 to 15.0 3.30 1.9 9.5 4-3 Waterloo Road sewer 4 3 1920–1984 29Q063 Williams Street 30P039 Hiawatha Avenue 12,15 15,18 1,834 8 21.9 to 23.7 2.30 1.8 20.1 N-129-60-20
-42-WP-R-WWMP
City of St
ockton
Wastwater Master Plan Update
Last Revised: 6-7-2022

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A V E

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WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 6\Figure 6-2. Existing Deficiencies Improvements.mxd - jsteiner - 7/15/2022 TF C W RU Regional Wastewater Control Facility
[PS
±
2-3
1 2
3 4
10 87
9 6
5 10
8 1-10 Collection System Service Areas
X-X Deficiency ID
[PS
±
[PS
±
[PS
±
[PS
±
[PS
±

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1-1
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4-1
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4-3Proposed Lincoln Street
Pump Station

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Priority 1
Priority 2
Priority 3&4
No Capacity Deficiency
Proposed Force Main
[PS
± Pump Station - No Capacity Deficiency
[PS
± Pump Station - Capacity Deficiency
[PS
± Pump Station - Proposed
Figure 6-2
Tentative Improvements to
Address Existing Capacity Deficiencies
City of Stockton
Wastewater Master Plan Update

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 6-4
. Notes and Recommendations for Addressing Identified Capacity Deficiencies, Existing Development Conditions ID # Designation Notes Recommendations
Prefer
red
SmartCover
MH
Prefer
red
SmartCover
Location Alternate MHs
Priority 1 Group
1-1 E. Marsh Street sewer The model shows potential
outflows at the upstream end of this line, but
capacity defic
iencies exist throughout
Confirm system
geometry; monitor the upstream end of this line
with Smar
tCover or equivalent technology 32R072 E. Marsh Street and Olympic Circl
e
32R081, 33R00
1, 33R006,
33R027
1-2 El Dorado Stre
et /
S. Center S
treet sewer
The model shows potential
backwater-driven outflows at the upstream end of
this line, but
capacity deficiencies exist throughout
Confirm system
geometry; monitor the upstream end of this line
with Smar
tCover or equivalent technology 38N073 El Dorado Stre
et and
McKinley P
ark
38N063, 38N038, 38N029,
38N026, 38N011
1-3 S. Wilson Way sewer
The model assumed ve
ry high I&I from this line due to a large flow difference between flow meters 6-1 and 6-5, but
it is possible that another large I&I source
exists elsewhere, such as one or more downstream MHs located in Mormon Slough
Confirm system
geometry; monitor the upstream end of this line
with SmartCover or equivalent technology; line/seal downstream MHs in Mormon Slough
34P082 S. Wilson Way and
E. Worth Street 34P054, 34P068, 34P089
1-4 E. 6th Street sewer This line is tributary to the El Dorado Street / S. Center Street sewer (see above); upsizing of that sewer could partially alleviate severe surcharging in this line Confirm system geometry; monitor the upstream end of this line with SmartCover or equivalent technology 37N034 E. 6th Street and S. San Joaquin Street 37N035, 37N038, 37N032
Priority 2 Group
2-1 E. Main Street sewer
The model shows Prior
ity 2 surcharging and capacity deficiencies throughout
this line; the line c
rosses the Marsh Street sewer, so opportunities may exist to combine flows, although a careful analysis of downstream impacts would be necessary
Confirm system
geometry; monitor the upstream end of this line
with SmartCover or equivalent technology 33R050 E. Main Street sewer west of S. Filbert Avenue
33R057, 33R056, 33R054,
33R046, 33R043, 33R039
2-2 W. Washington Stre
et /
Port Road 23 s
ewer
The model shows Prior
ity 2 surcharging and capacity deficiencies throughout
this line
Confirm system
geometry; monitor the upstream end of this line
with Smar
tCover or equivalent technology 34J016 W. Washington Stre et just
east of Por
t Road 14 34J017, 35J001
2-3 Do
n Avenue /
Meadow Avenue sewer
The line in question is located immediately downstream of the Don Avenue and Santiago PS; peak flow conditions should be confirmed
Confirm system
geometry; monitor the upstream end of this line
with Smar
tCover or equivalent technology; flow meter the lift
station, if possible
20G060 Don Avenue a
nd
Santiago Way
20G063, 20G077, 20G073,
21G007
2-4 S. El Dorado Street sewer
The model shows capac
ity deficiencies in this line that trigger backwater-induced surcharging in multip
le tributary lines; the surcharging becomes Priority 1 for modeled 2040 conditions; any upsizing of this line should consider reconfiguring various parallel sewers to discharge directly into this line, thus potentially eliminating t
he parallel sewers
Confirm system
geometry; monitor the upstream end of this line
with SmartCover or equivalent technology; reconfigure parallel sewers if improvements are made
35N076
Lateral sewer at
S. Hunter Street and
E. Jackson Street
35N060, 35N064, 35N079
Priority 3&4 Group
4-1 Market Street sewer The model shows Prior
ity 4 surcharging and capacity deficiencies throughout
this line
Confirm system
geometry; monitor the upstream end of this line
with Smar
tCover or equivalent technology 33M079 Market Str
eet west of
California S
treet
33N066, 33N070, 33N076,
33N083, 33M075, 33M079
4-2 Church Street /
Pe
rshing Avenue sewer
Significant portions of this line are known to be severely deteriorated and is a high priority for replacement. 30 percent design drawings were submitted in April 2021.

Construct t
he upstream invert of the replacement sewer at a
higher elevation to
improve velocities if feasible, concurrent or
prior to completing the Lincoln Street Pump Station and Force Main project.
none none none
4-3 Waterloo Ro
ad sewer
The model shows Prior
ity 4 surcharging and capacity deficiencies throughout
this line, but
the line is very deep, so any improvements would be a low priority based on capacity and d
epth of surcharging.

Confirm system
geometry; monitor the upstream end of this line
with SmartCover or equivalent technology 29P054 Waterloo Road and Sanguinetti Lane 29Q058, 29Q062, 29P070
Pump Station Capacity Improvements
-- Cumberland & 5-Mile
Slough PS Station is modeled as being over capa
city at peak flow conditions Verify the need for pump st ation capacity improvements through
flow metering and/or
pump runtime logging none none none
-- Don Avenue & S
antiago PS Station is modeled as being over capacity at peak flow conditions Verify the need for pump st ation capacity improvements through
flow metering and/or
pump runtime logging none none none
N-129-60-20-42-WP-R
-WWMP
City of Stockton
Was
twater Master Plan Update
Last Revised: 6-7-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 6
Analysis of Existing Flow Conditions
N-129-60-20-42-WP-R-WWMP
6-9 City of Stockton
Wastewater Master Plan Update
September 2022

6.4 PREVIOUSLY IDENTIFIED SYSTEM CONDITION DEFICIENCIES The City maintains and updates a CIP list to address existing system deficiencies and future needs for City wastewater collection system facilities. The projects on the CIP list are based on previous studies and address both capacity-related deficiencies and condition -related deficiencies. The capacity -related deficiencies are generally superseded by the recommendations of this Master Plan. The condition-related deficiencies, however, are not subject to reevaluation under this Master Plan , but nevertheless are assumed to remain applicable.

Condition-related deficiencies requiring rehabilitation of gravity sewers (designated as R -#) are summarized in Table 6-5. Condition-related deficiencies involving pump stations and force mains (designated as P-#) are summarized in Table 6-6. Both groups are presented schematically in Figure 6-3.

Gravity sewer projects are considered a high priority if design of improvements is already complete or in progress, or if such projects are otherwise considered by City staff to be an urgent need. Items P-1 through P-5 in Table 6-6 are considered a high priority based on longstanding need and a high consequence of system failure. All of the other listed gravity sewer and pump station projects are considered to be medium priority.

Improvements to the 14 -Mile Slough PS (Project P -1) have long been identified as necessary to address operational concerns. In addition, the long -term capacity needs of the station need to be identified so that the facility can be appropriately upsized to accommodate future development.

The 5 -Mile Slough force main (Project P -2) interconnects the 14 -Mile Slough PS, Swenson PS, Cumberland & 5-Mile Creek PS, and Plymouth & 5 -Mile Creek PS. Investigation of the force main and identification of rehabilitation measures/improvements is considered a high priority to ensure that force main operations remain uninterrupted.

The Lincoln Street PS and force main (Project P-3) have long been identified as being necessary to maintain system operations and to address a crit ical deficiency where the Market Street trunk sewer turns south and crosses Mormon Slough through an inverted siphon that is over 100 years old. According to City staff, the siphon is believed to be impacted by accumulated debris, and it is difficult or im possible to maintain properly due to its age and deteriorated condition. Some risk exists that the siphon could fail, which would entail prolonged bypass pumping and an emergency repair.

A parallel force main to serve the 14-Mile Slough PS and other pump stations in the northern part of the City (Project P-4) is considered to be an important need for long-term system resiliency. The length of the existing force main and suspected poor soil conditions along the alignment raises concerns about differential settlement or instabilities that could impact force main operation. Figure 6-3 shows a route identical to the existing force main. Alternative routes should be evaluate d during a preliminary engineering phase based on relative cost and exposure to unstable soils, seismic hazards, or other environmental factors.

Finally, the Swenson PS (Project P-5) is currently listed in the City’s CIP as in need of a capacity upgrade.

While the collection system model does not show this station to be capacity -limited, flow metering data from upstream gravity sewer locations indicate that this station allows incoming flows to back up into the upstream sewers during both wet and dry weather flow conditions. It is unclear whether the upstream surcharging is related to deteriorated condition of the pumps, operational settings, pump capacities being lower than currently reported, or some combination of these factors . Accordingly, this station has been added to the list of pump stations in Table 6-5 requiring attention.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 6-5. Previously Iden
tified Gravity Sewer Condition-Related Deficiencies
Designat
ion Name Extents Existi
ng Pipe Diameter, in Approximate Length, LF Priority City Project No.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 6
Analysis of Existing Flow Conditions
N-129-60-20-42-WP-R-WWMP
6-11 City of Stockton
Wastewater Master Plan Update
September 2022
Table 6-6. City-Identified Pump Stations and Force Mains with Condition-Related Concerns Designation Facilities Priority City Project No.

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M A T H E W S
R D

H A R D I N GW A Y

F A R M I N G T O NR D

A L P I N E A V E

H O W A R DR D

P A C I F I C A V E

E L D O R A D O S T

B E N J A M I N

H O L T D R

S P E R R Y R D

W I L S O N
W A Y

S I E R R A

N E V A D A S T

A I R P O R T W A Y

W E B E R
A V E

O A K S T

P A R K
S T

M A I N
S T

B U C K L E Y

C O V E W A Y

H O L M A N R D

H A M M E R L N

A L P I N E A V E

E L D O R A D O S T

C O U N T R Y

C L U B B L V D

F R E N C H C A M P R D

L O W E R S A C R A M E N T O R D

W I L S O N W A Y

S W A I NR D

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T H O R N T O N R D

N A V Y D R

C H E R O K E E R D

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M A N T H E Y
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R O T H R D

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WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 6\Figure 6-3. Condition-Related Deficiencies Identified by the City.mxd - jsteiner - 6/15/2022 1 2
3 4
10 8
7 9
6 5
10 8
1-10 Collection System Service Areas
Modeled Gravity Sewer
Modeled Gravity Sewer Identified for Rehab
Unmodeled Gravity Sewer Identified for Rehab (Project R-24) Force Main
Force Main Identified for Rehab
Proposed Force Main
[PS
±Pump Station
[PS
±Pump Station Identified for Rehab
[PS
±Proposed Pump Station
R-4
R-10
R-3
R-8
R-1
R-5
R-7
R-6
R-2
R-18
R-19
R-11
R-9
R-22
R-23
R-15
Figure 6-3
Condition-Related Deficiencies
Identified by the CIty
City of Stockton
Wastewater Master Plan Update
R-12
R-17
R-13
R-14
R-16
R-21
R-20
Notes:

1. Non-location-specific rehabilitation projects R-25, R-26, and R-27 not shown.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
7-1 City of Stockton
Wastewater Master Plan Update
September 2022
CHAPTER 7
Analysis of Future Flow Conditions
The purpose of this chapter is to present the results of the hydraulic model of the wastewater collection system for 2040 development conditions. The major sections of this chapter include:
• 2040 Development and Flow Generation Areas
• Analysis of 2040 Flow Conditions
• Analysis of Buildout Flow Conditions

7.1 2040 DEVELOPMENT AND FLOW GENERATION AREAS
Modeled conditions for the 2040 timeframe consist of flows for existing development conditions, as described in Chapter 6, plus future flows from the following areas that do not currently discharge to the City’s wastewater collection system:
• General Plan Major Development Areas
• General Plan Study Areas
• Additional 2040 Development Areas
• Unincorporated County Islands
• Areas on Septic Tanks

7.1.1 General Plan Major Development Areas
Major development areas identified as part of the City’s General Plan process include the areas summarized in Table 7-1. The major development areas in excess of 50 acres of developable area are shown on Figure 7-1. The two largest such areas are Mariposa Road Community and the Sanctuary, each of which has a planned developable area in excess of 1,000 acres.

One area of note in the major development areas list is the Open Window project. This area is planned to include mixed-use high-rise buildings in the downtown area. Although there are only 10.9 developable acres involved, a special flow facto r of 24,400 gpd per acre is used. This flow factor was developed in a September 2019 technical memorandum titled “Near-Term Development and Downtown Wastewater Collection System Capacity”.

7.1.2 General Plan Study Areas
In addition to the major development areas, the City’s General Plan also includes a total of sixteen study areas throughout the City. The areas in question are shown on Figure 7-1 and development information for these areas is presented in Table 7-2. Study Areas 15 and 16 are designated entirely as Open Space/Agriculture land use in the 2040 General Plan, but are nevertheless included on Figure 7-1 and in Table 7-2 for completeness.

7.1.3 Additional 2040 Development Areas
Five additional development areas were added to the 2040 modeling analysis to account for known or likely additional flow contributions. The areas in question are summarized in Table 7-3 and are shown on Figure 7-1. In all cases, the General Plan land use designations are used.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 7-1. Major Development Areas, 2040 General Plan Conditions Planned 2040 Development Area, acres
Low Density
Residential
Medium Density
Residential Commercial Industrial
Open
Window
Parks and
Recreation
Total
Area
Mariposa Road Community 939.0 585.0 150.0 0 0 206.3 1,880.3 Sanctuary 1,026.0 67.4 35.5 0 0 193.0 1,321.9
South Stockton Commerce Center 0 0 20.3 792.0 0 17.2 829.5 Westlake Villages 680.0 0 0 0 0 12.8 692.8
Cannery Park 272.0 16.0 104.0 0 0 0 392.0
North Stockton Projects III 355.0 0 0 0 0 0 355.0
NorCal Logistics Center 0 0 0 325.0 0 0 325.0
Tra Vigne 260.7 11.7 10.4 0 0 20.4 303.2
Airpark 599 0 0 5.4 259.7 0 0 265.1
Delta Cove 132.7 47.6 2.6 0 0 57.7 240.6
Mariposa Industrial Park 0 0 0 203.5 0 0 203.5
Sanchez-Hoggan Annexation 0 0 0 169.8 0 0 169.8
Crystal Bay 19.4 78.7 0 0 0 10.0 108.1
University Park 10.1 11.0 30.9 0 0 0 52.0
Weston Town Ranch 0 0 41.5 0 0 0 41.5
Veterans Affairs Clinic 0 0 37.0 0 0 0 37.0
Open Window 0 0 0 0 10.9 0 10.9
CarMax Superstore 0 0 10.6 0 0 0 10.6
Tuscany Cove 0 4.3 0 0 0 0 4.3
Thornton and Eight Mile Road 0 0 2.1 0 0 0 2.1
Airport Way and Sperry Road Commercial 0 0 2.0 0 0 0 2.0 Development
N-C-129-60-20-42-WP-R-TABLES-CH7
City of Stockton
Wastwater Master Plan Update
Last Revised: 10-29-21

A R C H

A I R P O R T R D

H A R N E Y
L N

M O R A D A L N

F R E M O N TS T

M A I N
S T

E I G H T M I L E R D

D R M A R T I N

L U T H E R K I N GJ R B L V D

C H A R T E RW A Y

W A S H I N G T O N S T

B A R B A R AT E R R YB L V D

F I L B E R T
S T

P E R S H I N G A V E

M A I N S T

C E N T U R Y B L V D

M A T H E W S
R D

H A R D I N GW A Y

C H E R O K E E
L N

M A I N
S T

A L P I N E A V E

L A T H R O P
R D

C O T T A G E
A V E

H O W A R DR D

P A C I F I C A V E

E L D O R A D O S T

B E N J A M I N H O L T D R

S P E R R YR D

H U T C H I N S
S T

A I R P O R T W A Y

H A ML N

O A K S T

P A R K S T

L A T H R O P R D

M C K I N L E Y
A V E

K E T T L E M A N
L N

H A R N E Y
L N

B U C K L E Y

C O V E W A Y

H O L M A N R D

H A M M E R L N

A L P I N EA V E

E L D O R A D O S T

C O U N T R Y

C L U B B L V D

F R E N C H C A M P R D

L O W E R

S A C R A M E N T O R D

W I L S O N
W A Y

M A R C H L N

R E Y N O L D SR A N C H P K

H A R L A N
R D

N A V Y D R

C H E R O K E E R D

M A R I P O S A R D

G O L D E N

V A L L E Y P K U N I O N
R D

M A N T H E Y
R D

R O T H R D

A R C H R D

W A T E R L O O R D

W E S T L N

P O R T O F

S T O C K T O N E Y

H A R L A N R D

M A R I P O S A
R D
Weber Grant
El
Dorado-Airport
Crystal Bay
Sanctuary
Delta Cove
Mariposa Road
Community
Westlake
Villages
Cannery
Park
North
Stockton
Projects III
Airpark 599
Tra Vigne
NorCal
Logistics
Center Sanchez-Hoggan
Annexation
University
Park
Mariposa
Industrial Park
South Stockton
Commerce Center
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 7\Figure 7-1. Areas of 2040 Development and Flow Generation.mxd - jsteiner - 6/15/2022 Major Developments
General Plan Study Area
Unincorporated Islands Not Currently Connected
Areas on Septic Tanks to be Sewer Connected
Additional 2040 Flow Contributing Areas
City of Stockton Sphere of Influence
Stockton City Limits
Figure 7-1
Areas of 2040 Development and
Flow Generation
City of Stockton
Wastewater Master Plan Update

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
Table 7-2. Study
Areas, 2040 General Plan Conditions
Planned 2040
Study Area, acres
Low Density
Residential
Medium Den
sity
Residential
Commercial Industrial
Open
Window
Parks and
Recreation
Total
Area
Study Area 1 –
Eight Mile Road Area 232.1 73.2 0.6 0 0 157.0 462.9
Study Area 2 – Pacific Avenue Corridor 0 4.7 3.6 0 0 0 8.3 Study Area 3 – West Lane and Alpine Road Area 59.8 21.7 6.2 0 0 0 87.7 Study Area 4 – Port / Waterfront 11.2 26.7 2.9 5.6 0 3.4 49.9 Study Area 5 – El Dorado Street / Center Street Corridor 0 17.2 1.8 0 0 0 19.0 Study Area 6 – Miner Avenue / Weber Avenue Corridor 0 18.0 3.4 0 0 0 21.3 Study Area 7 – Wilson Way Corridor 0 6.8 5.1 0 0 0 12.0 Study Area 8 – I-5 / Highway-4 Interchange 0 38.0 0.9 0 0 0 38.9 Study Area 9 – Railroad Corridor at California Street 0 19.3 1.5 0 0 0 20.7 Study Area 10 – I-5 and Charter Way Area 57.9 4.2 2.6 2.7 0 0 67.4 Study Area 11 – Charter Way / MLK Jr Boulevard Corridor 0 7.7 0.4 0 0 0 8.2 Study Area 12 – Airport Way Corridor 0 4.7 10.2 13.1 0 0 28.0 Study Area 13 – Mariposa Road and Charter Way Area 0 0 1.5 0 0 0 1.5 Study Area 14 – East Weston Ranch 0 0 14.8 0 0 0 14.8
Study Area 15 – South of French Camp Road 0 0 0 0 0 0 0 Study Area 16 – E. French Camp Road Area 0 0 0 0 0 0 0
Development
N-C-129-60-20-42-WP-R-TABLES-CH7
City of Stockton
Wastwa
ter Master Plan Update
Last Revised: 10-29-21

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
Chapter 7
Future Collection System Analysis
N-129-60-20-42-WP-R-WWMP
7-5 City of Stockton
Wastewater Master Plan Update
September 2022
Table 7-3. Additional 2040 Development Areas
Designation System ID Area, acres
VA Project 8 195.6
CSA-15 9 189.5
Insurance Auto Auction 9 139.0
AOB-96 6 101.9
Hammer Lane Hotel 2 15.5

7.1.4 Unincorporated County Islands
As discussed in Chapter 2 of this report, there exist a series of unincorporated County areas (referred to as “islands”) that are technically not within the Stockton City limits, but which are located inside or adjacent to the outmost City limits boundary. A total of 17 such areas have been identified, of which the following seven areas (shown on Figure 7-1) are either known to be on septic tanks or have no known connection to the City’s wastewater collection system:

Stockton Northeast
Elkhorn
Rancho San Joaquin
Wagner Heights
Oakridge-Swenson
Weber Grant
El Dorado/Airport
For purposes of this analysis, it is assumed all of the currently unconnected areas will be connected to the wastewater collection system by 2040. While no specific timeline exists for establishing such connections, this assumption is a conservative approach to estimating future flow conditions. The 2040 demands for these areas are estimated by applying the flow factors described in Chapter 4 to the relevant land use quantities established in the City’s General Plan.

7.1.5 Areas on Septic Tanks
As discussed in Chapter 6 of this report, there are areas of the City where sewer lines exist in the street, but some parcels are on septic tanks and were never connected to the adjacent sewers. These areas are shown on Figure 7-1. The areas in question are generally small and are located in older areas of the City.

As with the unincorporated islands, no specific timeline exists for connecting these parcels to the adjacent sewers; however, assuming that such connections will occur represents a conservative approach to estimating future flow conditions. As noted in Chapter 6, the parcels in question are generally limited to those designated as Low Density Residential in the City’s General Plan land use database. The 2040 demands for these areas are estimated by applying the Low Density Residential flow factor developed in Chapter 4 to the relevant parcels.

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
Chapter 7
Future Collection System Analysis
N-129-60-20-42-WP-R-WWMP
7-6 City of Stockton
Wastewater Master Plan Update
September 2022

7.2 ANALYSIS OF 2040 CONDITIONS
The following topics are addressed in this section:
• System Infrastructure to Serve Future Development
• Model Results for 2040 Conditions
• Improvements to Address 2040 Capacity Deficiencies

7.2.1 System Infrastructure to Serve Future Development Modeled future system infrastructure, including pump stations, force mains, and gravity sewers 12-inch diameter and larger , is shown in Figure 7-2. The indicated infrastructure layout is either based on a preliminary layout by a recent development project proponent, or on an analysis of surface topography, critical surface features (such as highways, railroads, and stream channels), and sewer pipe depths.

The exact configuration of collection system facilities serving future areas is subject to change as development proceeds. For modeled future flow conditions, all existing infrastructure is assumed to remain unchanged. Moreover, as with modeled existing flow conditions, the model treats pump stations as passing all incoming flows regardless of station capacity such that the capacities of pump stations and downstream gravity lines can be properly evaluated.

Past planning analyses assumed that the Mariposa Road development area would be served by a new pump station that would connect directly to the RWCF via a 43,000 -foot force main with an alignment primarily through Systems 6 and 5. This Master Plan has identified alternatives to that previous theoretical alignment that would reduce the amount of construction through congested areas and would minimize work on Navy Drive. It is assumed that the force main for the pump station serving the Mariposa Road Community development area would be aligned through either System 7 or System 8, as shown on Figure 7-2. Issues related to connecting the Mariposa Road Community development area to the existing system are discussed in Section 0 below.

7.2.2 Model Results for 2040 Conditions
Modeled surcharge results for the 10-year, 24-hour design storm under 2040 development conditions are shown on Figure 7-3. Each location where pipe surcharging is indi cated by the model are summarized in Table 7-4, along with the recommended diameter if the pipeline were to be replaced. The modeled system deficiencies for 2040 conditions are only slightly more severe than those described for existing conditions, but not fundamentally different. In addition, no additional Priority 1 surcharged lines are indicated for modeled 2040 conditions (as compared to those in Chapter 6); however, three additional lines show either Priority 2 or Priority 3&4 surcharging for modeled 2040 development conditions that did not surcharge under modeled existing peak flow conditions.

Additional surcharged lines under modeled 2040 conditions that did not surcharge under modeled existing peak flow conditions include:
• The Del Norte Street sewer from the Smith Canal and Fontana PS force main outlet to West Scotts Avenue
• The S. Airport Way sewer from South Longe Street spur to Sperry Road • The North Lincoln Street sewer from its upstream terminus to North Lincoln Street

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
0 1.50.75
Miles
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±[PS
±
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± [PS
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±
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±
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±
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±
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±
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±
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±
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±
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±
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±
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±
[PS
±
[PS
±[PS
±
[PS
±
[PS
±
[PS
±
[PS
±
§¨¦5
ÄÆ4
ÄÆ99
Gateway
PS
Sanctuary
PS
Newton
Road PS
Mariposa
PS
System 8
PSTidewater
PS
Priest
Road PS
Mariposa Road PS Force MainSystem 7 Alignment
Mariposa Road PS Force MainSystem 8 Alignment A R C H

A I R P O R T R D

H A R N E Y
L N

M O R A D A L N

F R E M O N TS T

M A I N S T

E I G H T M I L E R D

D R M A R T I N

L U T H E R K I N GJ R B L V D

C H A R T E R W A Y

W A S H I N G T O N S T

B A R B A R AT E R R YB L V D

C A L I F O R N I A S T

F I L B E R T
S T

P E R S H I N G A V E

M A I N S T

C E N T E R S T

D A V I S R D

C E N T U R Y B L V D

G U I L D
A V E

H A R D I N GW A Y

F A R M I N G T O NR D

U N I O N
R D

S T O C K T O N S T

A L P I N E A V E

L A T H R O P
R D

C O T T A G E
A V E

P A C I F I C A V E

E L D O R A D O S T

B E N J A M I N H O L T D R

S P E R R YR D

W I L S O N
W A Y

H U T C H I N S
S T

A I R P O R T W A Y

H A ML N

W E B E R
A V E
O A K
S T

P A R K S T

M A I N S T

C H E R O K E E
L N

M C K I N L E Y
A V E

K E T T L E M A N L N

H A R N E Y
L N

B U C K L E Y

C O V E W A Y

H O L M A N R D

M A I N S T

H A M M E R L N

A L P I N EA V E

L A T H R O P R D

C O U N T R Y

C L U B B L V D

F R E N C H C A M P R D

L O W E R S A C R A M E N T O R D

W I L S O N
W A Y

S W A I NR D

M A R C H L N

T H O R N T O N R D

R E Y N O L D SR A N C H P K

H A R L A N
R D

N A V Y D R M A R I P O S A R D

G O L D E N

V A L L E Y P K

M A N T H E Y
R D

R O T H R D

A R C H R D

W A T E R L O O R D

W E S T L N

P O R T O F

S T O C K T O N E Y

H A R L A N R D
24"
15"
18"
15"
12"
24"
21"
18"
15"
27"
27"
30"
15"
12"
27"
8"
12"
15"
12"
12"
15"
15"
42"
12"
36"
12"
21"
12"
18"
24"
18"
15"
12"
24"
30"
36"
12"
18"
12"
15"
15"
24"
12"
15"
30"
12"
18"
8"
12"
15"
27"
15"
15"
24"
12"
15"
15"
12"
18"
18"
21"
15"
21"
15"
18"
12"
21"
8"
18"
12"
27"
21"
24"
33"
12"
12"
21"
24"
12"
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12"
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30"
12"
27"
45"
12"
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24"
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18"
33"
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18"
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18"
18"
8"
12"
12"
21"
18"
12"
21"
21"
12"15"
54"
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 7\Figure 7-2. Modeled 2040 Collection System Facilities.mxd - jsteiner - 9/2/2022 Modeled Existing Gravity Sewer
Modeled Existing Force Main
Future Gravity Sewer
Future Force Main
[PS
±Existing Pump Station
[PS
±Future Pump Station
Major Developments
General Plan Study Area
Unincorporated Islands
Areas on Septic Tanks to be Sewer
Connected
Additional 2040 Developments
City of Stockton Sphere of Influence
Figure 7-2
Modeled Future
Collection System Facilities
City of Stockton
Wastewater Master Plan Update
Notes:

1. Facilities constructed during preparation of this Master Plan.

2. This figure does not include improvements identified in Chapter 6.

See Note 1

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
Chapter 7
Future Collection System Analysis
N-129-60-20-42-WP-R-WWMP
7-8 City of Stockton
Wastewater Master Plan Update
September 2022
Peak flow results for the 10 -year, 24-hour design storm at the 23 modeled existing pump stations are summarized in Table 7-5. As indicated, the Cumberland & 5-Mile Slough PS, Don Avenue & Santiago PS, and Westlake PS are all over capacity at modeled 2040 buildout peak flow conditions. In addition, the force mains for 14-mile Slough PS and Westlake PS are undersized for modeled 2040 peak flow conditions. It should be noted that the model may overstate peak flows at the Westlake PS because the development areas discussed in Section 7.1.1 and shown in Table 7-1 include approximately 87 acres of existing and planned lakes that are designated as Low Density Residential development. Removing such areas from the calculation results in 2040 peak flows much closer to the firm capacities of the pump station and force main.

Modeled results for 2040 conditions at the future pump station facilities are summarized in Table 7-6. All estimated future force main sizes are the smallest diameters at which the lines flow less than 8 feet per second for modeled buildout peak flow conditions. As indicated in the table, the Gateway PS, System 8 PS, and Priest Road PS are expected to have zero flow at 2040 conditions.

7.2.3 Improvements to Address 2040 Capacity Deficiencies Improvements to address capacity deficiencies for modeled 2040 conditions include all improvements identified in Chapter 6, plus the following items:

Gravity sewer facilities to serve 2040 General Plan development, as illustrated on Figure 7-2.

Pump station and force main facilities needed to serve 2040 General Plan development, as illustrated on Figure 7-2.

Capacity-deficient gravity sewers, as shown in Table 7-4.

Capacity-deficient pump stations and force mains, as shown in Table 7-5.

One issue of concern for the City involves the pump station location and force main alignment that would serve the planned Mariposa Roa d Community development area. As noted above, previous collection system planning showed the force main alignment along a northerly route through Systems 6 and 5, but this alignment is no longer considered preferable. Instead, as shown in Figure 7-2 above, it would be more suitable to have a force main alignment either through System 7 or through System 8.

The Mariposa Road Community development area is predicted to produce a peak flow of 13.7 mgd by 2040 and 25.2 mgd by buildout, based on the planning factors presented in Chapter 4. As shown in Table 7-7, the model shows available gravity flow capac ity within the existing gravity sewers of both systems through 2040 and beyond. (The two pathways share a common alignment from Fresno Avenue to Navy Drive.) Specifically, the existing gravity trunk sewers could accommodate flows from the Mariposa Road Community development area for an interim period, especially along the System 8 pathway.

However, the model indicates that insufficient gravity flow capacity exists to accommodate the Mariposa Road Community development area flows under buildout conditions.

Accordingly, the City will need to decide what infrastructure is needed right away to accommodate the Mariposa Road development area and whether some infrastructural requirements can be delayed. For purposes of master planning, it is recommended that the Mariposa Road development area pump station be constructed to allow for future expansion that can accommodate equipment capable of pumping all flows directly to the RWCF, but that a shorter force main be constructed in the interim that is directed into the System 8 pathway.

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
0 1.50.75
Miles

TF C W RU
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[PS
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§¨¦5
ÄÆ4
ÄÆ99

A R C H

A I R P O R T R D

H A R N E Y
L N

M O R A D A L N

F R E M O N TS T

M A I N S T

E I G H T M I L E R D

D R M A R T I N

L U T H E R K I N GJ R B L V D

C H A R T E R W A Y

W A S H I N G T O N S T

B A R B A R AT E R R YB L V D

C A L I F O R N I A S T

F I L B E R T
S T

P E R S H I N G A V E

M A I N S T

C E N T E R S T

D A V I S R D

C E N T U R Y B L V D

G U I L D
A V E

M A T H E W S
R D

H A R D I N GW A Y

F A R M I N G T O NR D

U N I O N
R D

S T O C K T O N S T

A L P I N E A V E

L A T H R O P
R D

C O T T A G E
A V E

H O W A R DR D

P A C I F I C A V E

E L D O R A D O S T

B E N J A M I N H O L T D R

S P E R R YR D

W I L S O N
W A Y

H U T C H I N S
S T

A I R P O R T W A Y

H A ML N

W E B E R
A V E
O A K
S T

P A R K S T

M A I N S T

C H E R O K E E
L N

M C K I N L E Y
A V E

K E T T L E M A N L N

H A R N E Y
L N

B U C K L E Y

C O V E W A Y

H O L M A N R D

M A I N S T

H A M M E R L N

A L P I N EA V E

L A T H R O P R D

C O U N T R Y

C L U B B L V D

F R E N C H C A M P R D

L O W E R S A C R A M E N T O R D

W I L S O N W A Y

S W A I NR D

M A R C H L N

T H O R N T O N R D

R E Y N O L D SR A N C H P K

H A R L A N
R D

N A V Y D R

C H E R O K E E R D

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G O L D E N

V A L L E Y P K

M A N T H E Y
R D

R O T H R D

A R C H R D

W A T E R L O O R D

W E S T L N

P O R T O F

S T O C K T O N E Y

H A R L A N R D

M A R I P O S A
R D
Figure 7-3
Modeled Capacity Deficiencies
10-Year, 24-Hour Storm
2040 Development Conditions
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 7\Figure 7-3. 2040 10yr24hr Capacity.mxd - jsteiner - 6/15/2022 Modeled Sewer Lines
Priority 1
Priority 2
Priority 3&4
Backwater-Induced SSO
Backwater-Induced Surcharging
No Surcharging
Force Main
Capacity-Deficient Force Main
Future Gravity Main
Future Force Main
[PS
± Pump Station - No Capacity Deficiency
[PS
± Pump Station - Capacity Deficiency
[PS
± Future Pump Stations
TF C W RU Regional Wastewater Control Facility
1 2
3 4
10 8
7 9
65 10
8 1-10 Collection System Service Areas
Gateway
PS
Sanctuary
PS
Newton
Road PS
Mariposa
PS
System 8
PSTidewater
PS
Priest Road
PS
Notes:

1. Possible System 8 alignment of the Mariposa Road PS force main not shown (see Figure 7-2).

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
Table 7-4
. Modeled Gravity Sewer Capacity Deficiencies, 2040 Development Conditions, 10-Year, 24-Hour Design Storm ID # Designati
on Priorities System
GIS Year
Constructed
Upstream
MH ID
Upstream
MH Location
Downstream
MH ID
Downstream

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
Table
7-5. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, 2040 Development Conditions Pump Sta
tion System
Firm
Capacity, mgd
Peak Flow,
mgd (a)
Force Main

N-C-129-60-20-41-WP-R-
TABLES-CHA7
City of Stoc
kton
Wastewater Master Plan Update
Last Revised: 06-10-22

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
Chapter 7
Future Collection System Analysis
N-129-60-20-42-WP-R-WWMP
7-12 City of Stockton
Wastewater Master Plan Update
September 2022
Table 7-6. Model Results for 2040 Conditions at Future Pump Station Facilities Name Development Area
Peak
Flow, mgd
Force Main
Length, feet
Force Main
Diameter,
inches (a)
Peak Flow
Velocity,
feet/sec
Gateway Study Area 1 north of Eight Mile Road 0 (c) <10 24 0 (c) Mariposa Mariposa Road Community 14.03 36,100 (b) 30 4.4 Newton Road CSA-15/Insurance Auto Auction 2.60 2,200 14 3.8 Priest Road Areas southwest of Stockton
Municipal Airport 0 (c) 2,300 14 0 (c)
Sanctuary Sanctuary 4.85 <10 14 7.0
System 8 Areas south of Arch Road and east of
Highway-99 0 (c) 4,300 24 0 (c)
Tidewater South Stockton Commerce Center 1.51 2,800 30 0.5 (a) Sized for buildout conditions.
(b) System 7 alignment assumed.
(c) No flow at 2040 conditions; required for buildout.

Table 7-7. Available Flow Capacity in Systems 7 and 8
System 7 Pathway
Available Qp Capacity, mgd Existing Pipes
Existing 2040 Buildout Diameter, in Length, LF
Mariposa Road to Ralph Ave 9.1 8.5 5.7 30 11,800
Ralph Ave to El Dorado St. 7.7 7.0 2.1 42 6,200
El Dorado St. to Fresno Ave 10.4 9.7 4.0 48 13,500
Fresno Ave to Houston Ave (a) 44.9 37.0 11.6 72 2,500
Houston Ave to Navy Drive (a) 43.1 32.5 0.8 72 6,100
System 8 Pathway
Available Qp Capacity, mgd Existing Pipes
Existing 2040 Buildout Diameter, in Length, LF
Marfargoa Road to Airport Way 21.5 17.1 12.7 42 14,200
Airport Way to El Dorado St. 35.5 28.6 14.1 66 5,600
El Dorado St. to Fresno Ave 51.3 44.0 25.3 72 17,100
Fresno Ave to Houston Ave (a) 44.9 37.0 11.6 72 2,500
Houston Ave to Navy Drive (a) 43.1 32.5 0.8 72 6,100
Development Area
Modeled Qp, mgd
Existing 2040 Buildout
Mariposa Road Community 0 14.0 25.2
(a) The System 7 and System 8 pathways are converged from Fresno Avenue to Navy Drive.

ATTACHMENTC
DRAFT
DRAFT EXHIBIT 1
Chapter 7
Future Collection System Analysis
N-129-60-20-42-WP-R-WWMP
7-13 City of Stockton
Wastewater Master Plan Update
September 2022

7.3 ANALYSIS OF BUILDOUT FLOW CONDITIONS
In addition to evaluating 2040 flow conditions, it is also necessary to consider collection system flows associated with the buildout of the City’s Sphere of Influence. The analysis of buildout flow conditions is needed to ensure that any future upsizing o f collection system pipes is adequate to accommodate development consistent with planned future land uses through General Plan buildout. Accordingly, the following topics are addressed in this section:
• Buildout Model Flow Assumptions
• Buildout Model Results

7.3.1 Buildout Model Flow Assumptions
Development of the buildout model requires adding future flow inputs that are not accounted for in the 2040 conditions model. Additional flow inputs fall into two categories:

1. Currently vacant parcels not accounted for in any of the 2040 development areas.

2. Additional flows that may be added to the 2040 development areas after 2040.

In the latter case, the development quantities associated with the various development areas do not necessarily reflect full buildout of th ose areas. As an example, the difference between the 2040 development quantities and the buildout quantities for Study Area 1 are shown in Table 7-8. As indicated in the table, a significant amount of additional development is assumed to occur in Study Area 1 between 2040 and buildout. Similar results exist for other 2040 development areas.

Table 7-8. Study Area 1 Development Quantities, 2040 vs. Buildout Land Use Category
Parcel Area, acres
2040 (a) Buildout
Economic and Education Enterprise 0 3,784.1
Low Density Residential 232.1 647.3
Medium Density Residential 73.2 143.0
High Density Residential 0 53.5
Commercial 0.6 17.2
Institutional 0 39.0
Parks and Recreation 157.0 153.6
TOTAL 462.9 4,837.7
(a) All 2040 development expected to occur south of Eight Mile Road.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 7
Future Collection System Analysis
N-129-60-20-42-WP-R-WWMP
7-14 City of Stockton
Wastewater Master Plan Update
September 2022
Figure 7-4 illustrates the difference between existing, 2040, and buildout conditions in terms of flow generation. Specifically, the figure shows the following four categories of parcels with regard to the generation of future flow:
• Flow producing parcels that are assumed to remain unchanged from existing conditions • 2040 areas of development and flow generation (as shown in Figure 7-1) • Currently vacant parcels assumed to produce flows at buildout (but not by 2040) • Parcels with non-flow-producing land uses

7.3.2 Buildout Model Results
Buildout model system surcharging results are presented in Figure 7-5. Sewer runs where surcharging is indicated are summarized in Table 7-9. The number of pipes where the model indicates surcharging is substantially greater than for 2040 conditions. Specifically, Table 7-9 shows a total of 14 sewer runs where modeled surcharging is indicated for buildout conditions but not for existing or 2040 conditions.

Buildout model results for existing pump stations are presented in Table 7-10. Buildout model results for future pump stations are presented in Table 7-11. In addition to the stations previously identified as being over capacity for 2040 conditions, the Drake & Highway-99 PS, Smith Canal & Fontana PS, Swenson (North) PS, and Waterloo & Roosevelt PS are all shown as over capacity for buildout peak flow conditions.

Moreover, in addition to the 14 -Mile Slough PS force main and the Westlake PS force main being undersized for buildout peak flow conditions (as also indicated for 2040 conditions), the Sinclair & Highway-4 PS force main is also shown as being undersized for buildout peak flow conditions.

For this analysis, a line that is modeled as surcharging at buildout conditions but not at existing or 2040 conditions is not considered adequate justification to trigger an improvement, due to the uncertainty of when and if such a flow condition will ever occur . If, however, the need for a condition -related improvement has already been identified for the line in question, then an upsizing of that line is justified if either of the following two conditions are met:

Surcharging under buildout conditions is expected to be severe enough that the risk of future outflows exists.

It has already been determined for other reasons that the pipe in question needs to be dug and replaced.

The application of this approach is presented in Chapter 8 of this report.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Figure 7-4
Parcel-Based Flow Generation
Existing vs. Future
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 7\Figure 7-4. Parcel-Based Flow Generation - Existing vs. Future.mxd - jsteiner - 3/25/2022

A R C H

A I R P O R T R D

H A R N E Y
L N

M O R A D A L N

F R E M O N T S T

M A I N
S T

E I G H T M I L E R D

D R M A R T I N

L U T H E R K I N GJ R B L V D

C H A R T E R W A Y

W A S H I N G T O N S T

B A R B A R AT E R R YB L V D

C A L I F O R N I A S T

F I L B E R T
S T

P E R S H I N G A V E

M A I N S T

C E N T E R S T

D A V I S R D

C E N T U R Y

B L V D

M A T H E W S
R D

H A R D I N GW A Y

F A R M I N G T O NR D

M A I N S T

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C O T T A G E
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E L D O R A D O S T

B E N J A M I N H O L T D R

S P E R R YR D

S T O C K T O N S T

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A I R P O R T W A Y

H A M L N

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H A Z E L T O N A V E

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M A I N S T

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M C K I N L E Y
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C O V E W A Y

H O L M A N R D

H A M M E R L N

A L P I N EA V E

E L D O R A D O S T

C O U N T R Y

C L U B B L V D

F R E N C H C A M P R D

L O W E R S A C R A M E N T O R D

W I L S O N W A Y

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R E Y N O L D SR A N C H P K

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H A R L A N R D

M A R I P O S A
R D
City of Stockton Parcels
Unchanged from Existing Conditions
Flow Producing After 2040
2040 Flow Generation Area
Non-Flow-Producing Land Use
City of Stockton Sphere of Influence 0 1.50.75
Miles

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
0 1.50.75
Miles

A R C H

A I R P O R T R D

H A R N E Y
L N

M O R A D A L N

F R E M O N TS T

M A I N S T

E I G H T M I L E R D

D R M A R T I N

L U T H E R K I N GJ R B L V D

C H A R T E R W A Y

W A S H I N G T O N S T

B A R B A R AT E R R YB L V D

C A L I F O R N I A S T

F I L B E R T
S T

P E R S H I N G A V E

M A I N S T

C E N T E R S T

D A V I S R D

C E N T U R Y B L V D

G U I L D
A V E

M A T H E W S
R D

H A R D I N GW A Y

F A R M I N G T O NR D

U N I O N
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S T O C K T O N S T

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L A T H R O P
R D

C O T T A G E
A V E

H O W A R DR D

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E L D O R A D O S T

B E N J A M I N H O L T D R

S P E R R YR D

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S T

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M A R I P O S A
R D
Figure 7-5
Modeled Surcharging Results
10-Year, 24-Hour Storm
Buildout Development Conditions
City of Stockton
Wastewater Master Plan Update
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 7\Figure 7-5. Buildout 10yr24hr Capacity.mxd - jsteiner - 6/15/2022 Modeled Sewer Lines
Priority 1
Priority 2
Priority 3&4
Backwater-Induced SSO
Backwater-Induced Surcharging
No Surcharging
Force Main
Capacity-Deficient Force Main
Future Gravity Main
Future Force Main
[PS
± Pump Station - No Capacity Deficiency
[PS
± Pump Station - Capacity Deficiency
[PS
± Future Pump Stations
TF C W RU Regional Wastewater Control Facility
1 2
3 4
10 8
7 9
65 10
8 1-10 Collection System Service Areas
Gateway
PS
Sanctuary
PS
Newton
Road PS
Mariposa
PS
System 8
PSTidewater
PS
Priest Road
PS
Notes:

1. Possible System 8 alignment of the Mariposa Road PS force main not shown (see Figure 7-2).

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 7-9. Modeled Gravity
Sewer Capacity Deficiencies, Buildout Development Conditions, 10-Year, 24-Hour Design Storm ID # Desig
nation Priorities System
GIS Year
Constructed
Upstream
MH ID
Upstream
MH Location
Downstream
MH ID
Downstream
MH Location
GIS Pipe
Dia, in
Total
Length, ft
No. of Pipe
Segments
Depth to Pipe
Crown, ft
Maximum
Flow, mgd
Maximum
Surcharge, ft
Minimum
Headspace, ft
Priority 1 Group (Ex. And 2040 Conditions)
1-1 E. Marsh Street sewer 1,2,4 6 1895–1940 32R072 Olympic Circle 33P105 S. Sierra Neva da
Street 18 7,406 21

4.0 to 10.4 4.34 5.9 0
1-2 El Dorado Street /
S. Center Street sewer 1,2,4 6 1905–1915 37N043 E. 6th Street 36M016 E. Charter Way 16 2,832 9 7.4 to 12.1 3.58 10.0 0 1-3 S. Wilson Way sewer 1,2 6 1947 34P082 E. Worth
Street 35P012 Mormon Slough 10,12 1,001 5 7.6 to 8.6 2.97 8.1 0 1-4
E. 6th Street 1,2 6 1900 37N034 S. San Joaquin
Street 37N043 El Dorado
Street 12 701 4 10.2 to 10.8 1.77 10.7 0
Priority 2 Group (Ex. & 2040 Conditions)
2-1 E. Main Street sewer 2,4 6 1910–1984 33T029 S. Oro Avenue 33Q014 E. Washington Street 12,16 8,756 27 7.6 to 10.3 1.95 8.2 0
2-2 W. Washington Street /
Port Road 23 sewer 2,3 5 no data 34J016 west of Port
Road 13 36H003 north of Navy
Drive 12,15,18 3,800 9 5.6 to 11.8 2.92 5.2 3.6
2-3 Don Avenue / Meadow
Avenue sewer 2 2 1957–1973 20G060 Santiago Way 21G051 Oak Creek Drive 12 2,171 10 8.1 to 9.8 1.75 8.4 0 2-4 S. El Dorado Street sewer 2,4 6 1900–1910 35M031 E. Worth Street 36N016 E. Charter Way 12 1,815 5 8.9 to 11.5 1.20 2.9 6.1 2-5 Del Norte Street sewer 2,4 5 1949–1959 34K004 Force main outlet 35K030 W. Scotts
Avenue 36 4,132 12 4.4 to 9.3 21.19 3.3 1.9
Priority 3&4 Group (Ex. & 2040 Conditions)
4-1 Market Street sewer 4 5 1900–1920 33M079 S. El Dorado Street 34L002
S. Lincoln Stree
t 12,14,16,
18 2,320 8 12.4 to 16.1 1.98 4.1

9.5 4-2 Church Street/Pershing
Avenue sewer 4 5 1917 34L022 S. Harrison
Street 36L035 Navy Drive 24 5,613 15 9.5 to 15.0 4.62 3.9 8.2 4-3 Waterloo Road sewer 4 3 1920–1984 29Q063
Williams Stree
t 30P039 Hiawatha
Avenue 12,15
1,834 8 21.9 to 23.7 2.57 2.9 19.0
4-4 N. Lincoln Street sewer 4 5 1920 33L036 upstream
terminus 33L039 N. Lincoln
Street 4 161 4 14.0 to 14.8 0.05 1.8 12.4
Buildout-Only Group
B-1 Sierra Nevada Street
sewer 1,2 3,6 1895–1900 32P048 E. Lindsay
Street 33P105 E. Sonora Street 18 3,312 9 5.1 to 10.5 3.69 6.2 0 B-2 Church Street trunk sewer 4 5,6 1895–1985 33P105 E. Sonora Street 34L037 S. Harrison
Street 27 9,558 27 9.4 to 13.0 7.59 2.5 8.8
B-3 Mormon Slough sewer 2,4 6 1956 34Q037 E. Jefferson
Street 34P088 Worth Street 24 2,617 5 4.7 to 18.6 7.08 3.7 1.2 B-4 Worth Street trunk sewer 4 6 1920–1945 34P088 S. Sierra Nevada Street 35L034 W. Anderson
Street 36 8,502 17 6.7 to 20.8 14.71 3.0 4.2
B-5 Navy Drive west trunk
sewer (42") 1,2,4 5 1997 34G023 San Joaquin
River crossing 36H902 RWCF 42 4,602 12 7.8 to 14.2 63.52 13.8 0 B-6 Oak Street trunk sewer 2,4 3 1900–1958 31P131 Grant Street 33K010 McNabb Place 21,24 8,444 25 8.8 to 11.8 4.49 2.2 7.4 B-7 N Pershing Avenue trunk
sewer 2,4 3 1958 33K010 Oak Street 31K106 Tuxedo Avenue 20,24 4,260 21 9.1 to 16.2 5.40 1.5 7.7 B-8 Oro Avenue / Horner
Avenue 1,2,4 4,6 1984 33T027 E. Main Street 32S052 S. Drake Avenue 12,18 2,817 10 21.5 to 25.8 4.34 10.2 11.3 B-9 Oak Creek Drive / Park
Woods Drive 4 2 1957 21G062 Meadow
Avenue 22G031 Bonniebrook
Drive 12 1,511 8 10.6 to 12.6 1.23 1.3 9.5
B-10 Union Street sewer 2,3 3 1890–1918 30N015 Harding Way 32N016 Oak Street 10,12 3,305 8 6.1 to 10.7 1.00 1.0 5.1 B-11 A.G. Spanos Boulevard
sewer 2,4 10 1993–2006 14F017 Thornton Road 16F018 Whistler Way 24 4,399 14 13.7 to 16.9 7.68 5.8 9.4 B-12 Weber Avenue sewer 3,4 5 1920 33L067 Mormon
Slough 33L048 N. Lincoln
Street 6,8 1,791 7 6.3 to 12.7 0.52 2.0 5.9
B-13 Navy Drive west trunk
sewer (30") 2 5 1959 34G016 San Joaquin
River crossing 36H007 RWCF 30,36 4,080 9 4.6 to 10.2 24.62 2.2 5.4 B-14 S. Airport Way sewer 1,2,4 8 1974 45R005 S. Longe Street 42R024 Sperry Road 18 5,022 16 7.5 to 12.3 15.20 12.9 0 B-15 Performance Drive 1,2 8 1974 44Q001 Aviation Drive 44R013 S. Airport Way 12 2,073 6 3.6 to 9.4 1.22 8.2 0 N-C-129-60-2
0-42-wp-r-tables-cha7
City of Stoc
kton
Wastewater Master Plan Update
Last Revised: 06-10-22

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 7-1

0. Modeled Pump Station Results, 10-Year, 24-Hour Design Storm, Buildout Development Conditions Pump Statio
n System
Firm
Capacity, mgd
Peak Flow,
mgd (a)
Force Main
Diameter,
in
Maximum Force Ma
in
Velocity, ft/se
c (a)
14-Mile Slough 10 (b) 60.58 30 19.1
Alexandria &
14-Mile Slough 2 1.97 1.23 15 1.5
Arch Road 8 8.70 4.39 24 2.2
Blossom Ranch 2 1.30 0.66 8 2.9
Brookside Estates 10 8.64 2.72 20 1.9
Camanche & Ridgeway 2 2.40 1.20 none --
County Hospital -- 2.16 0.89 dual 10 1.3
Cumberland & 5-Mile Creek 1 4.32 6.10 16 6.8
Don Ave & Santiago 2 0.79 1.60 15 2.0
Drake & Highway 99 4 3.54 4.34 14 6.3
Grupe Business Park 7 0.86 0.397 8 1.8
Kelly & Mosher Slough 1 4.32 1.86 12 3.7
March-Brookside & I-5 2 1.15 0.76 8 3.4
Origone 9 5.18 2.16 16 2.4
Plymouth & 5-Mile Creek 1 1.25 0.49 8 2.2
Sanguinetti 9 15.98 8.83 24 4.3
Sinclair Avenue & Highway 4 7 4.32 1.58 10 4.5
Smith Canal & Fontana 3 37.92 44.30 dual 30 7.0
Swenson (North) 2 20.16 20.23 dual 24 5.0
Thornton & Davis 2 1.22 1.20 8 5.3
Waterloo & Roosevelt 4 2.74 3.46 12 6.8
Westlake 10 4.35 5.03 12 9.9
Weston Ranch 8 15.98 10.03 dual 30 1.6
(a) Exceedances of pump station firm c
apacity and the force main velocity criterion of 8 ft/sec are highlighted in yellow. (b) Cannot be calculated due to unknown pump capacities; see Table 2-9.

N-C-129-60-20-41-WP-R-TA
BLES-CHA7
City of Stockt
on
Wastewater Master Plan Update
Last Revised: 06-10-22

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 7
Future Collection System Analysis
N-129-60-20-42-WP-R-WWMP
7-19 City of Stockton
Wastewater Master Plan Update
September 2022
Table 7-11. Model Results for Buildout Conditions at Future Pump Station Facilities Name Development Area
Peak
Flow, mgd
Force Main
Length, feet
Force Main
Diameter,
inches
Peak Flow
Velocity,
feet/sec
Gateway Study Area 1 14.88 <10 24 7.3
Mariposa Mariposa Road Community 25.22 36,100 (a) 30 8.0 Newton Road CSA-15/Insurance Auto Auction 4.50 2,200 14 6.5 Priest Road South Stockton Commerce
Center/Study Area 16 4.52 2,300 14 6.5
Sanctuary Sanctuary 4.24 <10 14 6.1
System 8 South Stockton Commerce
Center/Study Area 16 15.26 4,300 24 7.5
Tidewater South Stockton Commerce Center 23.71 2,800 30 7.5 (a) System 7 alignment assumed.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
N-129-60-20-42-WP-R-WWMP
8-1 City of Stockton
Wastewater Master Plan Update
September 2022
CHAPTER 8
Recommended Wastewater Collection System CIP
The purpose of this chapter is to present a recommended CIP for the City’s wastewater collection system.

The recommended CIP presented here includes collection system capacity improvements, as well as condition-related improvements previously identified by the City , as discussed in Chapter 6. The City’s existing CIP list is included as Appendix G. The major topics addressed in this chapter include:
• Cost Estimating Assumptions
• Recommended Capital Improvements
• Review of Potential Impacts on Rates and Fees
• Conclusions and Recommendations

8.1 COST ESTIMATING ASSUMPTIONS
Cost estimates prepared for this Master Plan are developed in accordance with the guidelines of the Association for the Advancement of Cost Engineering (AACE) International for a Class 5 Estimate. AACE International defines a Class 5 Estimate in the following manner:

Class 5 Estimate: This estimate is prepared based on limited information, where little more than proposed plant type, its location, and the capacity are known. Strategic planning purposes include, but are not limited to, market studies, assessment of viability, evaluation of alternate schemes, project screening, location and evaluation of resource needs and budgeting, and long -range capital planning.

Examples of estimating methods used would include cost/capacity curves and factors, scale-up factors, and parametric and modeling techniques. The expected accuracy ranges for this class estimate are -20 to -50 percent on the low side and +30 to +100 percent on the high side.

Construction and capital cost estimates are presented in March 2022 dollars corresponding to an Engineering News Record Construction Cost Index (ENR CCI) of 15,126.84 (San Francisco). Construction costs were developed based on a combination of data supplied from manufacturers, bids on other wastewater facilities design projects buil t by other public agencies, construction costs previously estimated by West Yost, and standard cost estimating guides. Subsequent preliminary and detailed design efforts will serve to refine and confirm the estimates presented herein.

Total CIP costs include mark-ups equal to 80 percent of base construction costs, and are listed below:
• Design and Construction Contingency: 35 percent
• Project Cost Allowances: 45 percent
— Engineering: 15 percent
— Construction Management: 15 percent
— Implementation: 15 percent
It is assumed that the recommended facilities will be developed in public rights -of-way or on public property; therefore, land acquisition costs have not been included. Construction cost estimates do not include costs for annual O&M nor any allowance for project financing costs.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 8
Recommended Wastewater Collection System Capital Improvement Plan N-129-60-20-42-WP-R-WWMP
8-2 City of Stockton
Wastewater Master Plan Update
September 2022
The development of capital cost estimates for th is recommended CIP involves the following cost estimation methods and assumptions:

1. All of the capital cost estimates presented in this chapter are expressed in current (March 2022) dollars. Escalation should be considered in the financial analysis for projects occurring in future years.

2. Where the basis for costs was previously estimated, those earlier estimates are escalated to the current ENR CCI value for March 2022. Costs based on existing City estimates were taken from the 2021 CIP list and have not been escalated.

3. For open-cut gravity sewer construction projects, a unit cost of $35 per inch-diameter lineal- foot is assumed, plus $15,000 per manhole. These costs are assumed to include excavation/backfill, sheeting and shoring, pipe construction, dewatering, lateral/sewer main connection, repaving, and mobilization/demobilization.

4. For cured-in-place pipe installation or pipe-bursting methods for rehabilitation, an assumed cost of $20 per inch-diameter lineal-foot is used, plus $2,500 per service lateral reinstatement, and $10,000 per epoxy-lined manhole.

5. For future pump station facilities, construction costs are capacity-based estimates using published cost curves, supplemented with cost information from pump station projects in California and Oregon. The estimates are representative of average site conditions and normal difficulty of construction.

6. For pump station force main piping, an assumed unit cost of $25 per inch-diameter lineal- foot is used. These costs are assumed to include excavation/backfill, sheeting and shoring, pipe construction, dewatering, repaving, and mobilization/demobilization.

8.2 RECOMMENDED CAPITAL IMPROVEMENTS
A recommended CIP list is presented in Table 8-1. The information presented in the table includes:
• An ID number assigned to the improvement
• Name of the improvement
• Description of the improvement
• Justification for the improvement
• Estimated time frame for construction/execution
• Replacement quantities involved
• Actions/notes
• Estimated capital cost
• City CIP Project ID No. (where applicable)
Existing City cost estimates are shown, where available. Otherwise, costs are estimated using the methods described above in Section 8.1.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 8-1. Recommended Ca
pital Improvement Plan
ID Name Descrip
tion Justification Time Frame Quantities Actions/Notes Capital Cost, $M City CIP Project Pump Statio
n and Force Main Improvements, Existing System
P-1 14-Mile S
lough PS Improvements Modify existing pump station to address mechanical equipment failures.

Existing pump station suffers from chronic mechanical failures that warrant modifications to accommodate different pumping
equipment.
2027
(start by
2023)
Pump station modifications
Proceed with
design and construction of station
improvements to
address short-term operational
concerns; conduct evaluation by 2023 to identify long-
term capa
city needs

3.60 UW2002
2/M20022
P-2 5-Mile Slough Force Main Inspect and rehabilitate or replace existing force main piping Previously identified as needing inspection/rehabilitation 2027
(start by
2023)
Force main mod
ification/
replacement
Proceed with inspection, assessment, and
rehabilitation/ replacement

0.3 (City estimate;
assessment only) M18015
P-3 Lincoln Street PS and Force Main Construct PS and force main; abandon existing siphon; redirect local flow inputs
Existing siphon is over 100 years old and in poor condition; siphon failure would have severe consequences for system operations 2027
(start by
2023)
~4 mgd pump stati
on and ~1,800 LF
of force main(a) Update previ
ous design; proceed with construction 8.60 UW24005
P-4 Westside Interceptor Parallel Force Main Construct new parallel force main serving 14-Mile Slough PS and other tributary pump stations
Existing pump force main sizing not adequate for future flow conditions; condition of existing force main unknown
2027
(start by
2023)
~32,000 LF of 36
-inch diameter
parallel force main(a)
Proceed with
design and construction of parallel force
main; estimated costs do not include ROW acquisition 51.8 none P-5 Swenson (North) PS Assess pump station components, operation, and capacity
Pump station is not keeping up with incoming flows for both wet and dry weather conditions
2027
(start by
2023)
TBD Proceed with
inspection, assessment, and
rehabilitation/ replacement 2.90 UW24003
P-6 Brookside Estates PS Inspect and
rehabilitate existing pump station
components Previously
identified as needing inspection/rehabilitation 2027 TBD Proceed with inspection, assessment, and
rehabilit
ation/ replacement 0.90 UW2300
3 P-7 College Park (Park View) PS Inspect and
rehabilitate existing pump station
components Previously
identified as needing inspection/rehabilitation 2027 TBD Proceed with inspection, assessment, and
rehabilit
ation/ replacement 0.80 UW2500
3 P-8 Don Avenue & Santiago PS Inspect and rehabilitate existing pump station components; upsize existing PS capacity, as needed
Previously identified as needing inspection/rehabilitation; modeled peak flows exceed station capacity 2027 TBD
Proceed with
inspection, assessment, and
rehabilit
ation/ replacement; flow or pump runtime
monitoring is recommended to confirm capacity
concerns

0.50 UW1301
0/M13010
P-9 Drake & Hwy-99 PS Inspect and
rehabilitate existing pump station
components Previously
identified as needing inspection/rehabilitation 2027 TBD Proceed with inspection, assessment, and
rehabilit
ation/ replacement 1.30 UW2500
5 P-10 Kelley & Mosher PS Inspect and
rehabilitate existing pump station
components Previously
identified as needing inspection/rehabilitation 2027 TBD Proceed with inspection, assessment, and
rehabilit
ation/ replacement 0.50 UW2400
4 P-11 Quail Lak
es (Alexandria and 14-Mile
Slough) PS
Inspect and
rehabilitate existing pump station
components Previously
identified as needing inspection/rehabilitation 2027 TBD Proceed with inspection, assessment, and
rehabilit
ation/ replacement 0.60 UW2101
5/M21015
P-12 Thornton & Davis PS Inspect and
rehabilitate existing pump station
components Previously
identified as needing inspection/rehabilitation 2027 TBD Proceed with inspection, assessment, and
rehabilit
ation/ replacement 0.70 UW1300
9/M13009
P-13 Waterloo & Roosevelt PS Inspect and rehabilitate existing pump station components
Previously
identified as needing inspection/rehabilitation; pump
station is
not keeping up with incoming flows for both wet and dry weather con
ditions
2027 TBD Proceed wi
th inspection, assessment, and
rehabilitation/ replacement 0.60 UW25004
P-14 Camanche & Ridgeway PS Inspect and
rehabilitate existing pump station
components
Previously
-identified capacity upgrade; no current indication of
capacity co
ncerns 2032 -- Assess phys
ical condition and functionality of pump
station; ad
dress any major defects 0.60 UW2500
2 P-15 Plymouth & 5 Mile Creek PS Inspect and
rehabilitate existing pump station
components
Previously
-identified capacity upgrade; no current indication of
capacity co
ncerns 2032 -- Assess phys
ical condition and functionality of pump
station; ad
dress any major defects 2.40 UW2300
1 P-16 Cumberland & 5-Mile Creek PS Assess pump station components, operation, and capacity; upsize existing PS capacity, as needed
Modeled peak flows exceed station capacity; pump station is not keeping up with incoming flows for both wet and dry weather conditions
2032 6.6 mgd pump station
Flow or pump runti
me monitoring is recommended to
confirm capac
ity concerns; cost estimate assumes a
new pump station; however, existing station may be
able to accommoda
te larger pumps

6.0 none
P-17 Pump Statio
n Rehabilitation and
Modernization
Implement improvements identified under
Recommended Studies Item S-2 below
Aging pump station throughout the City are in need of rehabilitation or replacement
Annual,
ongoing
Structural
, mechanical, electrical,
controls, s
ite and security
rehabilit
ation and modernization
Adjust annual
budgeted amount upon completion of
Item S-2 2.0/year none
N-129-60-20-
42-R-WWMP-TABLES Page 1 of 3
City of St
ockton
Wastewater Master Plan Update
Last Revised: 09-01-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 8-1. Recomm
ended Capital Improvement Plan
ID Name Descr
iption Justification Time Frame Quantities Actions/Notes Capital Cost, $M City CIP Project Rehabilit
ation of Existing Gravity Sewer Facilities
R-1 Church S
treet/Pershing Avenue trunk
sewer
Replace/realign/upsize existing 24-inch diameter VCP
along Church Street and Pershing Avenue from Harrison
Street to Navy Drive
Existing VCP line has adverse slopes, is more than 100 years old, and is in advanced state of deterioration 2027 ~5,600 LF of 30-inch diameter pipe; ~20 MHs
(a)
Finaliz
e existing design; proceed with construction of
identified improvements; should be implemented in
conjunction with Lincoln Street PS project (see above)

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Table 8-1. Recomm
ended Capital Improvement Plan
ID Name Descr
iption Justification Time Frame Quantities Actions/Notes Capital Cost, $M City CIP Project Capacity Impr
ovements to Existing Gravity Sewer Facilities
C-1 E. Marsh
Street sewer Upsize existing 18-inch diameter sewer Existing conditions model shows potential for severe surcharging and/or SSOs 2035 ~7,400 LF of 2
4-inch diameter pipe;
22 MHs(a) Monitor wi
th level sensor and/or flow meter 11.8 none
C-2 El Dorado Street /
S. Center Street sewer
Upsize existing 16-inch, 18-inch and 24-inch diameter
sewers
Existing conditions model shows potential for severe surcharging and/or SSOs 2035
~2,800 LF of 2
4-inch diameter pipe;
10 MHs(a) Monitor wi
th level sensor and/or flow meter 4.5 none
C-3 S. Wilson Way sewer Upsize existing 10-inch and 12-inch diameter sewers Existi ng conditions model shows potential for severe surcharging and/or S
SOs 2035 ~1,000 LF of 2
1-inch diameter pipe;
6 MHs Monitor wi
th level sensor and/or flow meter 1.5 none
C-4 E. 6th Street Upsize existing 12-inch diameter sewer Existing conditions model shows potential for severe surcharging and/or SSOs 2035
~700 LF of 18
-inch diameter pipe;
5 MHs(a) Monitor wi
th level sensor and/or flow meter 0.9 none
C-5 E. Main Street sewer Upsize existing 12-inch and 16-inch diameter sewers Existing conditions model shows potential for excessive surcharging 2035 ~8,700 LF of 1 8-inch diameter pipe;
~30 MHs(a) Monitor wi
th level sensor and/or flow meter 10.7 none
C-6 W. Washington Street / Port Road 23
sewer
Upsize existing 12-inch, 15-inch and 18-inch diameter
sewers Existing conditions model shows potential for excessive surcharging 2035 ~3,800 LF of 2
1-inch diameter pipe;
10 MHs(a) Monitor wi
th level sensor and/or flow meter 5.3 none
C-7 Don Avenue / Meadow Avenue sewer Upsize existing 12-inch and 16-inch diameter sewers Existing conditions model shows potential for excessive surcharging 2035 ~2,200 LF of 1
5-inch diameter pipe;
2,200 LF of 2
1-inch diameter pipe;
18 MHs(a)
Monitor wi
th level sensor and/or flow meter 5.5 none
C-8 S. El Dorado Street sewer Upsize existing 12-inch diameter sewer Existing conditions model shows potential for excessive surcharging 2035 ~1,800 LF of 1 5-inch diameter pipe;
6 MHs(a) Monitor wi
th level sensor and/or flow meter 1.9 none
C-9 Del Norte Street sewer Upsize existing 36-inch diameter sewer Existing conditions model shows potential for excessive surcharging 2035 ~4,100 LF of 4 2-inch diameter pipe;
~20 MHs(a) Monitor wi
th level sensor and/or flow meter 11.4 UW25010
Recommende
d Studies
S-1 Asset Condit
ion Assessment for Sanitary
Sewer Force Mains Existing City CIP line item
Pump statio
ns not listed above may have deficiencies; assessments
are warr
anted; power management technologies may reduce
operati
ng costs
2027 TBD Unde
rtake a program to prioritize and assess all City
pump stations

N-129-60-
20-42-R-WWMP-TABLES Page 3 of 3
City
of Stockton
Wastewater Master Plan Update
Last Revised: 09-01-2022

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 8
Recommended Wastewater Collection System Capital Improvement Plan N-129-60-20-42-WP-R-WWMP
8-6 City of Stockton
Wastewater Master Plan Update
September 2022
The major categories shown in Table 8-1 include:
• Pump Station and Force Main Improvements, Existing System (designated as P-#) • Rehabilitation of Existing Gravity Sewer Facilities (designated as R-#) • Capacity Improvements to Existing Gravity Sewer Facilities (designated as C-#) • Recommended Studies (designated as S-#)
• Watch List Items (designated as W-#)
• Projects to be Excluded from the City’s Existing CIP List (designated as X-#) All of these categories except the recommended studies and the projects to be excluded from the City’s existing CIP list are shown schematically in Figure 8-1. In addition Figure 8-1 depicts additional facilities needed to serve future development areas.

8.2.1 Pump Station and Force Main Improvements, Existing System There are 17 items shown for this category, all but two of which were identified in the City’s existing CIP list. The most significant items in the list are the 14-Mile Slough PS improvements (Item P-1), the 5-Mile Slough Force Main investigation and improvements (Item P-2), the Li ncoln Street PS and Force Main (Item P-3), the Westside Interceptor Parallel Force Main (Item P-4), and the Swenson PS (Item P-5). The remaining items on the list involve inspecting existing pump station components and/or capacities and determining needed improvements.

The 14 Mile Slough PS improvements are needed to address chronic mechanical failure of the pumping equipment. Investigation to fully diagnose the problems, followed by likely replacement of the pumping equipment and related structural and/or control system and valving modifications, are needed. Failure of the pump station would require costly and prolonged emergency operations.

The 5-Mile Slough force main interconnects the 14 -Mile Slough PS, Swenson PS, Cumberland & 5-Mile Creek PS, and Plymouth & 5 -Mile Creek PS. Investigation of the force main and identification of rehabilitation measures/improvements is considered a high priority to ensure that force main operations remain uninterrupted.

The construction and operation of the Lincoln Street PS and force main would enable the elimination of the siphon and associated gravity sewers at the Mormon Slough crossing. The siphon and gravity sewers on the existing alignment are more than 100 years old (per City GIS data) and are in an advanced state of deterioration. A failure of any portion of the existing facilities would require costly and prolonged emergency operations.

The Westside Interceptor Parallel Force Main is needed to address a lack of redundancy in the system in the event the existing force main fails. The existing force main is approximately 6½ miles long, so the construction of a parallel force main will be an extensive and costly improvement. The cost estimate shown in Table 8-1 does not include any allowances for acquisition of rights-of-way.

While the model indicates that the capacity of the Swenson PS is adequate to address existing and future peak flow conditions, flow monitoring conducted in from October 2020 to March 2021 indicates that this pump station does not keep up with incoming flows under both wet and dry weather conditions, thus resulting in backwater-induced surcharging in upstream gravity sewers. The inability of the station to keep up with incoming flows may have been a factor in past SSOs upstream in the system along Hammer Lane.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 8
Recommended Wastewater Collection System Capital Improvement Plan N-129-60-20-42-WP-R-WWMP
8-7 City of Stockton
Wastewater Master Plan Update
September 2022
Item P-17 is intended as an annual budget for as-yet undefined pump station projects, given that many of the City’s wastewater pump stations are relatively old and may rehabilitation or replacement. Item S-2 (described below) will generate and prioritize a list of pump station rehabilitation projects. The annual budget for Item P-17 should be adjusted in the future upon completion of the study under Item S-2.

8.2.2 Rehabilitation of Existing Gravity Sewer Facilities There are 27 items shown for this category, all of which were identified in the City’s existing CIP list. Items R-1 through R -10 are considered to be high priority and are recommended for completion within a five-year time frame (2027). Items R -11 through R -24 are considered to be medium priority and are recommended for completion within a ten -year time frame (2 032). Items R-25 though R-27 are general rehabilitation categories that are not location-specific.

8.2.3 Capacity Improvements to Existing Gravity Sewer Facilities There are nine items shown for this category, only two of which (Items C-5 and C-9) were identified in the City’s existing CIP list. Items C-1 through C-9 reflect the items shown in Table 7-4 for the Priority 1 Group and the Priority 2 Group. In all cases, it is recommended that the City proceed with surcharge and/or flow monitoring of the lines in question before proceeding with the design of improvements.

8.2.4 Recommended Studies
The following four studies are recommended for inclusion on the CIP list:
• S-1: Asset Condition Assessment for Sanitary Sewer Force Mains • S-2: Asset Condition Assessment for Sanitary Sewer Pump Stations • S-3: Corrosion and odor control study
• S-4: West Side Interceptor alignment study
Items S-1 and S-2 are general recommendations to inspect all other City sewer pump stations and force mains (over and above those identified above) to assess all aspects of their existing pump stations, including structural, mechanical, electrical, and operational elements , and the need for flow metering , SCADA connection, and data archiving. In addition, Item S-3 is based on City maintenance staff expressing concerns about existing collection system corrosion and odor control facilities.

Item P-4 above addresses the need to design and construct a parallel force main to serve the 14 -Mile Slough PS and other pump stations that discharge into the existing force main running from 14 -Mile Slough PS to Navy Drive. It is unclear, however, if the alignment of the existing force main is also suitable for a parallel force main or if other alignments will need to be considered. Item S-4 would entail a separate study to address this issue.

8.2.5 Watch List Items
There are seven items shown for this category, all of which either show significant surcharging that does not approach outflows under existing conditions, or are modeled as flowing more than 80 percent full and were previously identified in the City’s CIP list. For all of these items, either flow metering or remote level monitoring (e.g., SmartCover® or equivalent) is recommended.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 8
Recommended Wastewater Collection System Capital Improvement Plan N-129-60-20-42-WP-R-WWMP
8-8 City of Stockton
Wastewater Master Plan Update
September 2022

8.2.6 Projects to be Excluded from the City’s Existing CIP List Items X-1 through X -4 in Table 8-1 were identified in previous planning as requiring upsizing to accommodate existing or future development conditions. However, the Master Plan incorporates significant, new information, including the following:

There is a greatly improved understanding of how flows are distributed throughout the collection system as a result of recent collection system flow metering.

Wastewater flow generation rates on a per capita basis have dropped dramatically throughout the region since the late 2000s.

Development plans from the early and mid-2000s were significantly curtailed reflecting changes to the City’s General Plan.

As a result of these changes, none of the facilities in question appear to be approaching capacity with in the time frame of identified 2040 development and , therefore, should not be included in the CIP for capacity reasons. However, if one or more of these facilities are found to be in an advanced state of deterioration, those facilities should remain on th e City’s CIP list for rehabilitation. Periodic updates of this Master Plan will determine if and when these projects (or others) later need to be added into the CIP.

8.2.7 Additional Items Not Included in This Analysis
Certain items on the City’s existing CIP list are not included in this discussion because they are not relevant to the collection system or because they are peripheral items not requiring attention in this Master Plan.

In general, these items fall into the following categories:
• RWCF-related projects
• Stormwater pump stations with sewer line connections
• Other minor/miscellaneous improvements

8.3 REVIEW OF POTENTIAL IMPACTS ON RATES AND FEES
Appendix H provides an analysis of how the conclusions of this Master Plan affect the current wastewater rates and connection fees. The most recent rate study was adopted in 2019 and included a capital project list as well as O&M costs for the wastewater utility. The analysis presented in Appendix H does not replace the adopted rate study, but rather assesses whether the conclusions of the 2019 rate study remain valid and whether the planned annual rate increases are adequate and remain consistent with anticipated costs.

All development impact fees/connection fees (including wastewater connection fees) are currently under review under a separate City effort. The analysis presented in Appendix H acknowledges the connection fee reserves as a potential revenue source for some capital improvements. It is possible that through future analysis certain capital projects or portions of the capital projects included in the CIP may be appropriately funded from connection fee reserves. However, as a conservative assumption, the analysis in Appendix H assumes that none of the capital improvements identified in this chapter will be funded out of the connection fee reserve. Therefore, Appendix H assumes that the connection fee reserve will be used for selected future projects to the extent the reserves are sufficient, and that the connection fee revenues will be structured to keep pace with the revenue requirements for connection fee funded improvements. In accordance with existing City policy, wastewater infrastructure associated with future development projects will generally be developer funded.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
WEST YOST - N:\Clients\129 Stockton\60-20-42 Stockton WWMP\GIS\MXD\WWMP\Chapter 8\Figure 8-1. Proposed Collection System CIP Projects.mxd - jsteiner - 9/2/2022

A R C H

A I R P O R T R D

M O R A D A L N

F R E M O N TS T

M A I N
S T

E I G H T M I L E R D

C H A R T E R W A Y

C A L I F O R N I A
S T

F I L B E R T S T

P E R S H I N G A V E

M A R I P O S A
R D

C E N T E R S T

D A V I S R D
P O R T1 3 R D

F A R M I N G T O NR D

A L P I N E A V E

H O W A R DR D

P A C I F I C A V E

E L D O R A D O S T

B E N J A M I N

H O L T D R

S P E R R Y R D

S I E R R A

N E V A D A S T

A I R P O R T W A Y

O A K S T

H A Z E L T O NA V E

P A R K S T

B U C K L E Y

C O V E W A Y

H O L M A N R D

H A M M E R L N

A L P I N E A V E

E L D O R A D O S T

C O U N T R Y

C L U B B L V D

F R E N C H C A M P R D

L O W E R

S A C R A M E N T O R D

W I L S O N W A Y

M A R C H L N

T H O R N T O N R D

N A V Y D R

C H E R O K E E R D

M A R I P O S A R D

M A N T H E Y
R D

R O T H R D

A R C H R D

W A T E R L O O R D

W E S T L N

P O R T O F

S T O C K T O N E Y

H A R L A N R D
24"
15"
18"
15"
18"
15"
12"
24"
18"
27"
27"
30"
12"
27"
8"
12"
15"
12"
12"
15"
21"
15"
42"
36"
12"
36"
21"
12"
18"
24"
15"
18"
15"
12"
21"
24"
30"
36"
12"
18"
12"
15"
15"
24"
12"
15"
30"
12"
12"
18"
8"
12"
15"
27"
15"
24"
15"
12"
18"
15"
12"
18"
21"
15"
21"
18"
12"
21"
8"
18"
12"
27"
21"
24"
24"
33"
12"
12"
21"
24"
12"
15"
30"
12"
27"
45"
12"
15"
24"
18"
21"
18"
33"
18"
18"
15"
15"
18"
18"
8"
12"
21"
18"
12"
21"
18"
21"
12"15"
54"
Existing Gravity Sewer
Existing Gravity Sewer Identified for Rehab
Gravity Sewer Capacity Deficiency
Watch List
Future Gravity Sewer
Existing Force Main
Existing Force Main Identified for Rehab
Future Force Main
[PS
± Existing Pump Station
[PS
± Pump Station Identified for Improvements
[PS
± Future Pump Station
TF C W RU Regional Wastewater Control Facility
Major Developments
General Plan Study Area
Unincorporated Islands
Additional 2040 Flow Contributing Areas
City of Stockton Sphere of Influence
Notes:

1. Facilities constructed during preparation of this Master Plan.

2. Items R-24 through R-27 not shown; see Figure 6-3.
0 1.250.625
Miles
Figure 8-1
Collection System CIP Projects
and Other Future Facilities
City of Stockton
Wastewater Master Plan Update

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1
Chapter 8
Recommended Wastewater Collection System Capital Improvement Plan N-129-60-20-42-WP-R-WWMP
8-10 City of Stockton
Wastewater Master Plan Update
September 2022
Based on the findings of Appendix H, annual rate increases will continue to be necessary, as previously anticipated, and the annual increase will need to be between 6.0 and 6.5 percent through fiscal year (FY) 2028. Smaller rate increases are indicated from FY 2029 through FY 2035. These findings are subject to a variety of assumptions about future growth and cost escalation, and are reasonable based on current information but subject to change over time. An updated formal rate study will be needed in 2024.

8.4 CONCLUSIONS AND RECOMMENDATIONS
Key conclusions and recommendations from the development of the recommended CIP include:

The cost estimates presented in this chapter are planning level estimates suitable for financial planning and subject to refinement as preliminary and final design engineering is performed.

It is recommended that the City address the pump station and force main improvements identified in Items P-1 through P-17 of Table 8-1, as follows:
a. The 14-Mile Slough PS improvements (Item P-1) are considered a high priority due to the potential consequences of ongoing mechanical failures. It is recommended that the City proceed expeditiously with the design and implementation of improvements. b. The 5-Mile Slough Force Main (Item P-2) is considered a high priority due to the potential of force main failure. It is recommended that the City proceed expeditiously with the identification and implementation of improvements.
c. The Lincoln Street PS and force main (Item P-3) is considered a high priority due to the potential for failure of the Mormon Slough siphon and associated gravity sewers. It is recommended that the City proceed exp editiously with the design and construction of this project.
d. The Westside Interceptor Parallel Force Main (Item P-4) is considered a high priority due to the potentially high consequences in the event of failure of the existing force main. It is also needed to accommodate anticipated future projected flows. It is recommended that the City proceed expeditiously with determining the best approach for providing redundancy and then proceed with the design of the project. e. The Swenson and 5-Mile Slough PS (Item P-5) is considered a high priority due to chronic flow backups and the potential for upstream SSOs. It is recommended that the City proceed expeditiously with the identification and implementation of pump station improvements.
f. Items P-6 through P-16 are considered moderate priority based on previous City findings regarding the condition of these facilities. It is recommended that the City proceed with the identification and implementation of improvements.
g. It is recommended that the City proceed with an annual budget for as yet undefined pump station projects (Item P-17) based on the knowledge that many of the City’s wastewater pump stations are relatively old, and all pump stations require periodic rehabilitation.

Item S-2 (described below) will generate and prioritize a list of pump station rehabilitation projects. The annual budget for Item P-17 should be adjusted in the future, upon completion of study under Item S-2.

ATTACHMENT C
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Chapter 8
Recommended Wastewater Collection System Capital Improvement Plan N-129-60-20-42-WP-R-WWMP
8-11 City of Stockton
Wastewater Master Plan Update
September 2022
It is recommended that the City address the gravity sewer rehabilitation improvements identified in Items R-1 through R-27 of Table 8-1, as follows:
a. Items R-1 through R-10 are considered to be a high priority. It is recommended that the City proceed with construction of these improvements by 2027. b. Items R-11 through R-24 are considered to be a medium priority. It is recommended that the City proceed with planning, design, and construction of improvements by 2032. c. Items R -25 though R -27 are general re habilitation categories that are not location - specific. It is recommended that the City proceed with such activities on an ongoing basis.

It is recommended that the City undertake flow metering and/or surcharge monitoring to confirm modeled capacity exceedances for Items C-1 though C-9.

It is recommended that the City undertake the following studies in support of future collection system improvements:
a. A full assessment of all City-owned sewer pump stations to evaluate all structural, mechanical, electrical, and operational elements, as well as the need for flow metering, SCADA connection, and data archiving.
b. A full assessment of all City-owned sewer pump station force main s to evaluate pipe integrity and the need for rehabilitation/improvements. c. A West Side Interceptor alignment study to determine the appropriate alignment for construction of a parallel force main under Item P-1 described above. d. A corrosion and odor control study to assess the need for improvements to the City’s corrosion and odor control facilities.

It is recommended that the various Watch List items identified in this chapter be either flow metered or monitored with remote level telemetry devices to confirm the extent of any capacity limitations.

It is recommended that items X-1 through X-4 be excluded from the City’s current CIP list unless one or more of these facilities are found to be in an advanced state of deterioration, in which case they should remain on the City’s CIP list for rehabilitation.

It is recommended that the City implement rate increases consistent with the adopted 2019 Rate Study to maintain adequate funding for the wastewater utility.

ATTACHMENT C
DRAFT
DRAFT EXHIBIT 1

Council Water CommitteeOctober 13, 2022

Council Water Committee
October 13, 2022