San Marcos City Council
June 27, 2023

Appendix G
Drainage Study

Preliminary Drainage Study for Las Posas
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PRELIMINARY DRAINAGE STUDY
For

GRAN VISTA
Preparation/Revision Date:

August 25, 2021/ February 17,2022
APN: 219-121-1500
219-121-1600
W.O. 3087-0007
Prepared for:

WPI-Las Posas/Mission, LLC
Contact: Andrew Sun
18300 Von Karman Ave., Suite 880
San Diego, CA. 92612
Telephone:
(949) 943-8550 x850
Prepared by:

Alisa S. Vialpando, RCE #47945
Hunsaker & Associates San Diego, Inc.
9707 Waples Street
San Diego, CA 92121
Telephone: (858) 558-4500
Hunsaker & Associates
San Diego, Inc.

Alisa S. Vialpando, R.C.E. #47945
President
N
o. 47945
Exp. 12/31/21

Preliminary Drainage Study for Gran Vista
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TABLE OF CONTENTS

SECTION
Chapter 1 Executive Summary I

1.1 Introduction

1.2 Vicinity Map

1.3 Summary of Existing Conditions

1.4 Summary of Developed Condition

1.5 Summary of Results

1.6 Conclusion

1.7 References
Chapter 2 Methodology & Model Development II

2.1 County of San Diego Drainage Design Criteria

2.2 Design Rainfall Determination
- 100-Year, 6-Hour Rainfall Isopluvial Map
- 100-Year, 24-Hour Rainfall Isopluvial Map

2.3 Runoff Coefficient Determination

2.4 Rainfall Intensity Determination
- Maximum Overland Flow Length & Initial Time
of Concentration Table
- Urban Watershed Overland Time of Flow Nomograph
- Gutter & Roadway Discharge-Velocity Chart
- Manning’s Equation Nomograph
- Intensity-Duration Design Chart

2.5 Rational Method Model Development Summary
Chapter 3 Hydrologic Analysis- EXISTING CONDITION III
100-Year Design Storm
Chapter 4 Hydrologic Analysis- DEVELOPED CONDITION IV
100-Year Design Storm
Chapter 5 Detention Basin Analysis V
Chapter 6 Hydraulic Analysis VI
Chapter 7 Hydrology Maps VII
Chapter 8 FEMA MAP VIII
Chapter 9 Reference Information (Report and Map) IX & HEC-RAS Ananlysis
Preliminary Drainage Study for Gran Vista
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Preliminary Drainage Study for Gran Vista
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CHAPTER 1 EXECUTIVE SUMMARY

1.1 Introduction
Gran Vista project is located at the northwest intersection of North Las Posas Road and West Mission Road in the City of San Marcos, California (See the Vicinity Map below).

The Gran Vista proposes 120 three story, townhome units (Occupancy: R3 Townhome/U; Construction Type V-B) with a maximum permitted density of 15.7 units per acre. The site will also include common recreational spaces, underground vaults, sidewalks, access road and private driveways.

The project is bound by a drainage channel and single-family neighborhoods to the north and west, North Las Posas Road to the east, and West Mission Road and a commercial parcel to the south. The commercial parcel has been developed with a single-story CVS building and associated pharmacy drive through and surface parking.

The project and the CVS parcel share two common access points: (1) a driveway at the signalized intersection of North Las Posas Road and Palm Road and (2) a driveway on West Mission Road that allow left-in and right-in/right-out traffic movements. Both driveways have been improved with enhanced paving and landscaping.

This drainage report will quantify the proposed runoff for the 100-year frequency storm event and provide calculations demonstrating that the post-developed flows will not exceed the capacity of the existing downstream drainage facilities. Proposed facilities include storm drain, curb inlets, catch basins, water quality/ flow control (hydromodification) and detention underground vaults. The proposed two Vaults for Preliminary Drainage Study for Gran Vista
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Gran Vista project will not only act as peak flow attenuation but also address water quality and hydromodification concerns. A separate report has been prepared which details the proposed treatment and flow control features for the Gran Vista project.

Refer to the Stormwater Quality Management Plan (SWQMP) for Gran Vista prepared by Hunsaker & Associates San Diego, Inc. (August 2021).

Per FEMA Map Panel 06073C0789H effective date 05/16/2012, the project site is mostly located outside any FEMA 100-year floodplain zone. However, a small portion of slope grading, an underground vault and connecting to an existing storm drain southwest of the site are proposed within Zone X, which is defined as areas determined to be outside the 0.2% annual chance floodplain. In addition, a very minimal slope grading is proposed southwest of the site, along the northeast edge of Mission Rd, within Zone AE which is defined as areas that have a 1% probability of flooding every year. The Base flood elevation along the northern edge of Mission Rd (which is approximately at 565.63 ft per the Las Posas LOMR 12-09-1988P eff 2013), is actually not reaching to the top of the regraded slope 570 ft. The minimal slope grading and filling won’t have any impact on the WSE. the LOMR or CLOMR will be required for the project. However, a HEC-RAS Hydraulic analysis is provided for the portion where filling is proposed within Zone AE to compare between the Base Flood Elevation in the existing and proposed conditions (for the small portion south of the site along the Mission Road edge. Please see Chapter 6 for the HEC-RAS analysis and results.

Sections 401 and 404 of the Clean Water Act are not applicable to the site since the property does not have waters of the U.S. onsite and since the project does not intend to discharge dredged or filled material into waters of the United States.

As mentioned above, water quality study has separately been prepared for this site to address potential stormwater pollutants, site design, and proposed structural BMPs for water quality and hydromodification compliance. Refer to the Stormwater Quality Management Plan (SWQMP) for Gran Vista prepared by Hunsaker & Associates San Diego, Inc. (August 2021).

Per County of San Diego drainage criteria, the Modified Rational Method can be used to determine peak design flowrates when the contributing drainage area is less than 1.0 square mile. Since the total watershed area discharging from the site is less than 1.0 square mile, the AES-2015 computer software was used to model the runoff response per the Modified Rational Method. Methodology used for the computation of design rainfall events, runoff coefficients, and rainfall intensity values are consistent with criteria set forth in the “County of San Diego 2003 Hydrology Manual.” A more detailed explanation of methodology used for this analysis is listed in Chapter 2 of this report

1.2 Summary of Existing Conditions
In existing condition, the 7.6-ac Gran Vista project site consists of two-mass graded pads. The pad located in the northerly portion of the planning is elevated above North Las Posas Road and is higher than the remaining portion of the planning area. The Preliminary Drainage Study for Gran Vista
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lower pad, located in the southerly portion of the site, is elevated above West Mission Road. Vegetation on the site is limited to grasses and small shrubs. A few trees are located along the periphery of the site, adjacent to the channel and North Las Posas Road.

The runoff from the project site, in its existing conditions, flows from the north and the east to the southwest corner where it is routed via an existing 12” CMP riser to a 12” existing corrugated metal pipe. After comingling with the total flow from the commercial parcel south of the project, total flow is conveyed to the storm channel west via 12” pipe.

The storm channel ultimately discharges into Posas Creek south. Per the Hydrology & Hydraulic Study for CVS Pharmacy prepared by Excel Engineering and dated February 9, 2009, the 100 year peak flow from the 8.474 acres is 6.75 cfs.

However, the site in its pre-development conditions consists approximately of 8.68 acres of watershed area with a total flow of 11.09 cfs at the discharge point into the storm channel west of the site (i.e. 12” storm drain). Please refer to the Hydrology & Hydraulic Study for CVS Pharmacy prepared by Excel Engineering and dated February 9, 2009 in Chapter 3
TABLE 1 - Summary of Pre-development Q100
Attachment*
Node
Number
on
Exhibit
Discharge
Location
Drainage
Area
(ac)
Tc (min)
100-Year
Peak Flow
(cfs)
H
Pre-development 3 southwest
corner 8.681 19 11.09
* Per the Hydrology & Hydraulic Study for CVS Pharmacy prepared by Excel Engineering and dated February 9, 2009
P6 = 3.3 inch
Runoff factor C = 0.35 (assuming Soil Type D for the entire site)

1.3 Summary of Developed Conditions
The post-developed condition of the site will consist of 120 three story, townhome units (Occupancy: R3 Townhome/U; Construction Type V-B) with a maximum permitted density of 15.7 units per acre, streets and associated utilities including a storm drain system necessary to convey site runoff through the project area. In addition, two underground vaults located southwest and southeast of the site will be constructed for hydromodification, and peak flow detention purposes. The vaults will be used as upstream storage units to store the 1.5 DCV and release in an appropriate flow rate to the volume based modular wetland units downstream of the vaults to address water quality requirements. One flow based modular wetland was proposed south of the site to replace the sand filter and address the water quality requirement for the Existing Drive. For additional discussion and sizing calculations for the treatment unit, please Preliminary Drainage Study for Gran Vista
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reference the Stormwater Quality Management Plan (SWQMP) for Gran Vista prepared by Hunsaker & Associates San Diego, Inc. (August 2021).

The stormwater runoff will be collected by inlets, and routed towards the vaults. The vaults will come with an internal riser which will have a low orifice that has been sized to drawdown the water quality volume (1.5 DCV) in 36 hrs, and an internal weir to separate the water quality flows form the rest of the HMP and peak flows.

The rest of the riser’s orifices have been sized to moderate discharge flows to comply with flow-control (HMP) requirements and at the same time allow peak flows to exit the vault in a rate that doesn’t exceed the capacity of the existing downstream drainage facilities.

Runoff coefficients of 0.71 has been used based on High Density Residential Land use of 24.0 DU\A or less (the site’s maximum permitted density is 15.7 units per acre), and soil type D was assumed for the entire site for simplicity and being more conservative.

Per the County of San Diego rainfall isopluvial maps, the design 100-year rainfall depth for the project site is 3.3 inch.

The Proposed Condition Hydrology Map (Exhibit 1) in Chapter 7 shows the developed site with its subareas to each inlet, or catch basin location. Table-2 below summarizes the Q100 Unmitigated flow at the POC.

TABLE 2 - Summary of Unmitigated Developed Flows
Exhibit
Node
Number
on
Exhibit
Discharge Location
Drainage
Area
(ac)
Tc (min)
100-Year
Peak Flow
(cfs)
1 108 Vault 2 east 4.0 10.86 15.12
1 204 Vault 1 West 1.9 9.07 8.07
1 1
Discharge into storm
channel at southwest
corner of the site

8.3 11.65 24.58
Due to the increased flow associated with the development of Gran Vista , peak flow attenuation will be achieved by the proposed vaults. The risers within the vaults will be sized and include orifices along their height necessary to achieve outlet flow less than the pre-development flow shown on Table 1 above. The resultant discharge at Node 1 will continue downstream and confluence with Posas Creek and then to Lake San Marcos. Since this project is subject to comply with hydromodification requirements, the Preliminary Drainage Study for Gran Vista
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design of all vaults have been coordinated with those calculations which are part of the SWQMP for Gran Vista.
.

Table-3 below summarizes the Q100 Mitigated flow at Node 1.

TABLE 3 - Summary of Mitigated Developed Flows
Exhibit
Node
Number
on
Exhibit
Discharge Location
Drainage
Area
(ac)
Tc (min)
100-Year
Peak Flow
(cfs)
1 108 Vault 2 east 4.0 18.6 6.68
1 204 Vault 1 West 1.9 17.07 2.94
1 1
Discharge into storm
channel at southwest
corner of the site

8.3 19.83 11.18

1.4 Summary of Results
Conveyance of the Q100 runoff flows through the Gran Vista site required storm drain system to route flows to the underground storage vaults and MWS units to address water quality, hydromodification and peak flow attenuation. The 12”pipe at the discharge location will be replaced with a 24” pipe 9see chapter 6 for the capacity calculations for the proposed 24’ pipe at the discharge location).

Design for the storm drain system and hydraulic calculations will be conducted as part of the final engineering drainage study.

Two permanent detention underground vaults were included in the design of the site for hydromodification, peak flow attenuation, and to provide the required storage for the water quality design captured volume. The two vaults and two Modular Wetland units address the water quality requirements. Per the hydrologic and detention analysis conducted as part of this study, the detention analysis for all vaults is included in Chapter 5 of this report. The table below summarizes the flow reductions at the discharge location.

The flow from the site is attenuated to make sure that the post-developed flows will not exceed the capacity of the existing downstream drainage facilities (post development flows compared to the pre-development flows at the point of compliance southeast corner of the project (POC-1/ Node 1). See table 4 below Preliminary Drainage Study for Gran Vista
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TABLE 4 – Pre-development Condition vs. Post-development Condition Discharge
Location
Pre-
development
Condition
Area (ac)
Post-
development
Condition
Area (ac)
Pre-
development
: 100-Year
Peak Flow
(cfs)
Post-
development:
100-Year
Peak Flow
(cfs)
Q100 Flow
Difference
(cfs)
southeast
corner 8.681 8.3 11.09 11.18 0.09
Conclusion
The proposed development of Gran Vista can be roughly graded and improved with storm drain to accommodate the ultimate expected flows from development. In addition, with the proposed drainage facilities such as curb inlets, storm drain, water quality, flow control and detention vaults, runoff can be mitigated to accepted San Diego County standards.

The proposed project will not substantially alter the existing drainage pattern of the site.

There will be a slight increase in the peak discharge from the site. The increase is negligible, at 0.8%, and will not impact downstream properties or drainage facilities.

1.5 References
San Diego County Hydrology Manual, County of San Diego Department of Public Works Flood Control Division, June 2003.

San Diego County Hydraulic Design Manual, County of San Diego Department of Public Works Flood Control Division, September 2014
San Diego County Drainage Design Manual, County of San Diego Department of Public Works Flood Control Division, July 2005
County of San Diego San Diego SUSMP, County of San Diego, January 2011 Standard Drawings, City of San Diego, 2012.

Erosion and Sediment Control Handbook, Goldman, Jackson, Bursztynsky, 1986 Stormwater Quality Management Plan for Gran Vista, Hunsaker & Associates San Diego, Inc., August 2021.

Excel Engineering Hydrology/Hydraulic Study In References Preliminary Drainage Study for Gran Vista
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Preliminary Drainage Study for Gran Vista
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CHAPTER 2

METHODOLOGY
Preliminary Drainage Study for Gran Vista
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2-1 Modified Rational Method Hydrologic Analysis
Computer Software Package – AES-2015
Design Storm - 100- year return interval
Land Use – High Density Residential
Soil Type – Per the NRCS Web Soil Survey, the site soil consists of Hydrologic soil group C and D. For simplicity and to be more conservative, Group D was assumed for the entire Site. Group D soils have very slow infiltration rates when thoroughly wetted.

Consisting chiefly of clay soils with a high swelling potential, soils with a high permanent water table, soils with clay pan or clay layer at or near the surface, and shallow soils over nearly impervious materials, Group D soils have a very slow rate of water transmission.

Runoff Coefficient - In accordance with the County of San Diego standards, runoff coefficients were based on land use, and Soil Type per San Diego County Hydrology Manual.

For proposed conditions, Runoff coefficients of 0.71 has been used based on High Density Residential Land use of 24.0 DU\A or less (the site’s maximum permitted density is 15.7 units per acre)
Rainfall Intensity- The rainfall intensity is determined per the San Diego County Hydrology Manual based on 6-hour precipitation amounts and calculated time of concentrations. Six-hour precipitations are taken from the San Diego County Hydrology Manual isopluvials. P6=3.3 inch
Method of Analysis – The Rational Method is the most widely used hydrologic model for estimating peak runoff rates. Applied to small urban and semi-urban areas with drainage areas less than 1.0 square miles, the Rational Method relates storm rainfall intensity, a runoff coefficient, and drainage area to peak runoff rate. This relationship is expressed by the equation:

Q = CIA, where:

Q = The peak runoff rate in cubic feet per second at the point of analysis.

C = A runoff coefficient representing the area - averaged ratio of runoff to rainfall intensity.

I = The time-averaged rainfall intensity in inches per hour corresponding to the time of concentration.

A = The drainage basin area in acres.

To perform a node-link study, the total watershed area is divided into subareas which discharge at designated nodes.

Preliminary Drainage Study for Gran Vista
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The procedure for the subarea summation model is as follows:
(1) Subdivide the watershed into subareas with the initial subarea being less than 10 acres in size (generally 1 lot will do), and subsequent subareas gradually increasing in size. Assign upstream and downstream nodal numbers to each subarea to correlate calculations to the watershed map. (2) Estimate an initial T c by using the appropriate nomograph or overland flow velocity estimation.
(3) Using the initial T c, determine the corresponding values of I. Then Q = CIA. (4) Using Q, estimate the travel time between this node and the next by Manning’s equation as applied to the particular channel or conduit linking the two nodes.

Then, repeat the calculation for Q based on the revised intensity (which is a function of the revised time of concentration)
The nodes are joined together by links, which may be street gutter flows, drainage swales, drainage ditches, pipe flow, or various channel flows. The AES-2003 computer subarea menu is as follows:

SUBAREA HYDROLOGIC PROCESS

1. Confluence analysis at node.

2. Initial subarea analysis (including time of concentration calculation).

3. Pipeflow travel time (computer estimated).

4. Pipeflow travel time (user specified).

5. Trapezoidal channel travel time.

6. Street flow analysis through subarea.

7. User - specified information at node.

8. Addition of subarea runoff to main line.

9. V-gutter flow through area.

10. Copy main stream data to memory bank

11. Confluence main stream data with a memory bank

12. Clear a memory bank
At the confluence point of two or more basins, the following procedure is used to combine peak flow rates to account for differences in the basin’s times of concentration.

This adjustment is based on the assumption that each basin’s hydrographs are triangular in shape.
(1). If the collection streams have the same times of concentration, then the Q values are directly summed,
Qp = Qa + Qb; Tp = Ta = Tb
Preliminary Drainage Study for Gran Vista
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(2). If the collection streams have different times of concentration, the smaller of the tributary Q values may be adjusted as follows:
(i). The most frequent case is where the collection stream with the longer time of concentration has the larger Q. The smaller Q value is adjusted by the ratio of rainfall intensities.

Qp = Qa + Qb (Ia/Ib); Tp = Ta
(ii). In some cases, the collection stream with the shorter time of concentration has the larger Q. Then the smaller Q is adjusted by a ratio of the T values.

Qp = Qb +Q a (Tb/Ta); Tp = Tb
Underground storm drains are analyzed in a similar way. Flow data obtained from the surface model for inlets and collection points are input into the nodes representing those structures. Design grades and lengths are used to compute the capacity of the storm drains and to model the downstream travel times.
2-3 Hydraulic Model Analysis
In order to provide adequate flood control, increases in peak flow rates at the outfall location for this site were mitigated using the proposed Vaults.

The hydrology calculations discussed above provide peak flowrates for the vaults’ inflow, which are entered into a separate program called RickRatHydro. The RickratHydro was used to produce an inflow hydrograph for the project drainage areas to each vault, based on the area, time of concentration, P6 value, runoff coefficient, and peak flow rate.

Mitigation within the each vault was modeled using SWMM 5.1. The Hydrograph that was generated from RickRatHydro was used as an input data for the inflows to the storage unit in the SWMM model. The riser was modeled using stage discharge table (Rating Curve in SWMM), and the volume was modeled using the storage stage table 9Storage Curve). The initial depth within the vaults was set at the depth that is associated with the water quality volume.

To approve that regarding the slope within the floodway will not have any impact on the WSE and will not change the BFE, HEC-RAS analysis was provided for the existing conditions and proposed conditions. For the existing conditions, the HEC-RAS analysis for the cross sections 1200 and 1100 per the Las Posas LOMR 12-09-1988P eff 2013 was used. The said results were compared to the output from the HEC-RAS analysis for the cross sections at the same locations in the proposed conditions Preliminary Drainage Study for Gran Vista
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San Diego County
Hydrology Parameters

P24 = 5.60
in
Project
Location
33'09'
01"
1 17'11'22"

P6 = 3.30
in
Project
Location
33'09'
01"
1 17'11'22"

3.30 59%3.30

5.60 5.60

3.30 Pre-developm
ent
Post Development for
Las Posas Site
Post d
evelopment for the Commercial site south
Per HYDROLOGY& HYDRAULIC STUDY FOR CVS PHARMACY prepared by Excel engineering
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CHAPTER 3

HYDROLOGIC ANALYSIS

PRE DEVELOPMENT

CONDITINS
Preliminary Drainage Study for Gran Vista

PRE DEVELOPMENT CONDITINS
100 – Year Design Storm
Preliminary Drainage Study for Gran Vista
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PER THE HYDROLOGY& HYDRAULIC STUDY FOR CVS PHARMACY PREPARED BY EXCEL ENGINEERING, DATED JULY 2009

HYDROLOGY STUDY FOR

CVS PHARMACY, LAS POSAS AND MISSION ROAD

ATTACHMENT H
EXISTING CONDITIONS Q100 CALCULATIONS
SEE CHAPTER 8 FOR EXISTING CONDITIONS DRAINAGE EXHIBIT

EXISTING CONDITION
100 YEAR STORM EVENT

San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2004 Version 7.4 Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 02/08/09
------------------------------------------------------------------------ 08030 CVS PHARMACY
PRE DEVELOPMENT 100 YR STORM
NODE 1 TO 3
------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** ------------------------------------------------------------------------ Program License Serial Number 4012
------------------------------------------------------------------------ Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 3.300
24 hour precipitation(inches) = 5.700
P6/P24 = 57.9%
San Diego hydrology manual 'C' values used
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 1.000 to Point/Station 2.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 577.200(Ft.)
Lowest elevation = 576.500(Ft.)
Elevation difference = 0.700(Ft.) Slope = 1.400 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:

The maximum overland flow distance is 70.00 (Ft)
for the top area slope value of 1.40 %, in a development type of Permanent Open Space
In Accordance With Table 3-2
Initial Area Time of Concentration = 12.50 minutes
(for slope value of 1.00 %)
Rainfall intensity (I) = 4.815(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.350 Subarea runoff = 0.184(CFS)
Total initial stream area = 0.109(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 2.000 to Point/Station 3.000 **** IRREGULAR CHANNEL FLOW TRAVEL TIME ****
______________________________________________________________________ Estimated mean flow rate at midpoint of channel = 5.671(CFS) Depth of flow = 0.295(Ft.), Average velocity = 1.842(Ft/s) ******* Irregular Channel Data ***********
----------------------------------------------------------------- Information entered for subchannel number 1 :

Point number 'X' coordinate 'Y' coordinate
1 0.00 2.40

EXISTING CONDITION
100 YEAR STORM EVENT

2 50.00 0.00
3 100.00 1.00
Manning's 'N' friction factor = 0.026
----------------------------------------------------------------- Sub-Channel flow = 5.672(CFS)
' ' flow top width = 20.884(Ft.)
' ' velocity= 1.842(Ft/s)
' ' area = 3.079(Sq.Ft)
' ' Froude number = 0.846
Upstream point elevation = 576.500(Ft.)
Downstream point elevation = 566.600(Ft.)
Flow length = 741.600(Ft.)
Travel time = 6.71 min.

Time of concentration = 19.21 min.

Depth of flow = 0.295(Ft.)
Average velocity = 1.842(Ft/s)
Total irregular channel flow = 5.671(CFS)
Irregular channel normal depth above invert elev. = 0.295(Ft.) Average velocity of channel(s) = 1.842(Ft/s)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 3.649(In/Hr) for a 100.0 year storm Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 3.038
Subarea runoff = 10.904(CFS) for 8.572(Ac.)
Total runoff = 11.088(CFS) Total area = 8.681(Ac.) Depth of flow = 0.379(Ft.), Average velocity = 2.178(Ft/s) End of computations, total study area = 8.681 (Ac.)

HYDROLOGY STUDY FOR

CVS PHARMACY, LAS POSAS AND MISSION ROAD

ATTACHMENT I
EXISTING + PROJECT CONDITIONS Q100 CALCULATIONS

EXISTING CONDITION CALCULATIONS FROM EXCEL ENGINEERING

DRAINAGE STUDY USED FOR FLOWS OF POST-DEVELOPED
CALCULATIONS AT NODE 20 AND 25
EXISTING+DEVELOPED AREA TO NODE 25
100 YEAR STORM EVENT

San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2004 Version 7.4 Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 02/09/09
------------------------------------------------------------------------ 08030 CVS PHARMACY
100 YEAR STORM EVENT

RUNOFF FLOW FROM EXISTING AND DRIVE AISLE
NODES 1-2-25, 4-5-25, AND 18-19-25
------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** ------------------------------------------------------------------------ Program License Serial Number 4012
------------------------------------------------------------------------ Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 3.300
24 hour precipitation(inches) = 5.700
P6/P24 = 57.9%
San Diego hydrology manual 'C' values used
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 1.000 to Point/Station 2.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 577.200(Ft.)
Lowest elevation = 576.500(Ft.)
Elevation difference = 0.700(Ft.) Slope = 1.400 %
Top of Initial Area Slope adjusted by User to 1.473 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:

The maximum overland flow distance is 70.00 (Ft)
for the top area slope value of 1.47 %, in a development type of Permanent Open Space
In Accordance With Table 3-2
Initial Area Time of Concentration = 12.50 minutes
(for slope value of 1.00 %)
Rainfall intensity (I) = 4.815(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.350 Subarea runoff = 0.184(CFS)
Total initial stream area = 0.109(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 2.000 to Point/Station 25.000 **** IRREGULAR CHANNEL FLOW TRAVEL TIME ****
______________________________________________________________________ Estimated mean flow rate at midpoint of channel = 4.011(CFS) Depth of flow = 0.259(Ft.), Average velocity = 1.689(Ft/s) ******* Irregular Channel Data ***********
----------------------------------------------------------------- Information entered for subchannel number 1 :

EXISTING+DEVELOPED AREA TO NODE 25
100 YEAR STORM EVENT

Point number 'X' coordinate 'Y' coordinate
1 0.00 2.40
2 50.00 0.00
3 100.00 1.00
Manning's 'N' friction factor = 0.026
----------------------------------------------------------------- Sub-Channel flow = 4.011(CFS)
' ' flow top width = 18.341(Ft.)
' ' velocity= 1.689(Ft/s)
' ' area = 2.374(Sq.Ft)
' ' Froude number = 0.827
Upstream point elevation = 576.500(Ft.)
Downstream point elevation = 566.600(Ft.)
Flow length = 741.600(Ft.)
Travel time = 7.32 min.

Time of concentration = 19.82 min.

Depth of flow = 0.259(Ft.)
Average velocity = 1.689(Ft/s)
Total irregular channel flow = 4.011(CFS)
Irregular channel normal depth above invert elev. = 0.259(Ft.) Average velocity of channel(s) = 1.689(Ft/s)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 3.577(In/Hr) for a 100.0 year storm Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 2.176
Subarea runoff = 7.601(CFS) for 6.109(Ac.)
Total runoff = 7.784(CFS) Total area = 6.218(Ac.) Depth of flow = 0.332(Ft.), Average velocity = 1.994(Ft/s) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 25.000 to Point/Station 25.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1
Stream flow area = 6.218(Ac.)
Runoff from this stream = 7.784(CFS)
Time of concentration = 19.82 min.

Rainfall intensity = 3.577(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 4.000 to Point/Station 5.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Neighborhod Commercial )
Impervious value, Ai = 0.800
Sub-Area C Value = 0.790
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 576.560(Ft.)
Lowest elevation = 575.900(Ft.)
Elevation difference = 0.660(Ft.) Slope = 1.320 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:

The maximum overland flow distance is 60.00 (Ft)
for the top area slope value of 1.32 %, in a development type of Neighborhod Commercial
In Accordance With Table 3-2
Initial Area Time of Concentration = 4.50 minutes
EXISTING+DEVELOPED AREA TO NODE 25
100 YEAR STORM EVENT

(for slope value of 1.00 %)
Calculated TC of 4.500 minutes is less than 5 minutes, resetting TC to 5.0 minutes for rainfall intensity calculations Rainfall intensity (I) = 8.695(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.790 Subarea runoff = 0.398(CFS)
Total initial stream area = 0.058(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 5.000 to Point/Station 25.000 **** IRREGULAR CHANNEL FLOW TRAVEL TIME ****
______________________________________________________________________ Estimated mean flow rate at midpoint of channel = 1.520(CFS) Depth of flow = 0.206(Ft.), Average velocity = 2.434(Ft/s) ******* Irregular Channel Data ***********
----------------------------------------------------------------- Information entered for subchannel number 1 :

Point number 'X' coordinate 'Y' coordinate
1 0.00 0.84
2 24.00 0.00
3 24.50 0.50
Manning's 'N' friction factor = 0.018
----------------------------------------------------------------- Sub-Channel flow = 1.520(CFS)
' ' flow top width = 6.077(Ft.)
' ' velocity= 2.434(Ft/s)
' ' area = 0.624(Sq.Ft)
' ' Froude number = 1.338
Upstream point elevation = 575.900(Ft.)
Downstream point elevation = 569.880(Ft.)
Flow length = 327.000(Ft.)
Travel time = 2.24 min.

Time of concentration = 6.74 min.

Depth of flow = 0.206(Ft.)
Average velocity = 2.434(Ft/s)
Total irregular channel flow = 1.520(CFS)
Irregular channel normal depth above invert elev. = 0.206(Ft.) Average velocity of channel(s) = 2.434(Ft/s)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Neighborhod Commercial )
Impervious value, Ai = 0.800
Sub-Area C Value = 0.790
Rainfall intensity = 7.172(In/Hr) for a 100.0 year storm Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.790 CA = 0.358
Subarea runoff = 2.168(CFS) for 0.395(Ac.)
Total runoff = 2.567(CFS) Total area = 0.453(Ac.) Depth of flow = 0.250(Ft.), Average velocity = 2.774(Ft/s) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 25.000 to Point/Station 25.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2
Stream flow area = 0.453(Ac.)
Runoff from this stream = 2.567(CFS)
Time of concentration = 6.74 min.

Rainfall intensity = 7.172(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 18.000 to Point/Station 19.000 **** INITIAL AREA EVALUATION ****

EXISTING+DEVELOPED AREA TO NODE 25
100 YEAR STORM EVENT

______________________________________________________________________ Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Neighborhod Commercial )
Impervious value, Ai = 0.800
Sub-Area C Value = 0.790
Initial subarea total flow distance = 32.600(Ft.)
Highest elevation = 581.280(Ft.)
Lowest elevation = 579.100(Ft.)
Elevation difference = 2.180(Ft.) Slope = 6.687 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:

The maximum overland flow distance is 95.00 (Ft)
for the top area slope value of 6.69 %, in a development type of Neighborhod Commercial
In Accordance With Table 3-2
Initial Area Time of Concentration = 3.40 minutes
(for slope value of 5.00 %)
Calculated TC of 3.400 minutes is less than 5 minutes, resetting TC to 5.0 minutes for rainfall intensity calculations Rainfall intensity (I) = 8.695(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.790 Subarea runoff = 0.096(CFS)
Total initial stream area = 0.014(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 19.000 to Point/Station 25.000 **** IRREGULAR CHANNEL FLOW TRAVEL TIME ****
______________________________________________________________________ Estimated mean flow rate at midpoint of channel = 0.206(CFS) Depth of flow = 0.072(Ft.), Average velocity = 2.566(Ft/s) ******* Irregular Channel Data ***********
----------------------------------------------------------------- Information entered for subchannel number 1 :

Point number 'X' coordinate 'Y' coordinate
1 0.00 1.44
2 26.70 0.44
3 39.50 0.00
4 44.50 2.57
Manning's 'N' friction factor = 0.018
----------------------------------------------------------------- Sub-Channel flow = 0.206(CFS)
' ' flow top width = 2.233(Ft.)
' ' velocity= 2.566(Ft/s)
' ' area = 0.080(Sq.Ft)
' ' Froude number = 2.385
Upstream point elevation = 579.100(Ft.)
Downstream point elevation = 575.240(Ft.)
Flow length = 46.900(Ft.)
Travel time = 0.30 min.

Time of concentration = 3.70 min.

Depth of flow = 0.072(Ft.)
Average velocity = 2.566(Ft/s)
Total irregular channel flow = 0.206(CFS)
Irregular channel normal depth above invert elev. = 0.072(Ft.) Average velocity of channel(s) = 2.566(Ft/s)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Neighborhod Commercial )
Impervious value, Ai = 0.800
Sub-Area C Value = 0.790
Rainfall intensity = 8.695(In/Hr) for a 100.0 year storm Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.790 CA = 0.036
EXISTING+DEVELOPED AREA TO NODE 25
100 YEAR STORM EVENT

Subarea runoff = 0.220(CFS) for 0.032(Ac.)
Total runoff = 0.316(CFS) Total area = 0.046(Ac.) Depth of flow = 0.084(Ft.), Average velocity = 2.856(Ft/s) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 25.000 to Point/Station 25.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 3
Stream flow area = 0.046(Ac.)
Runoff from this stream = 0.316(CFS)
Time of concentration = 3.70 min.

Rainfall intensity = 8.695(In/Hr)
Summary of stream data:

Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr)
1 7.784 19.82 3.577
2 2.567 6.74 7.172
3 0.316 3.70 8.695
Qmax(1) =

1.000 * 1.000 * 7.784) +

0.499 * 1.000 * 2.567) +

0.411 * 1.000 * 0.316) + = 9.194
Qmax(2) =

1.000 * 0.340 * 7.784) +

1.000 * 1.000 * 2.567) +

0.825 * 1.000 * 0.316) + = 5.475
Qmax(3) =

1.000 * 0.187 * 7.784) +

1.000 * 0.550 * 2.567) +

1.000 * 1.000 * 0.316) + = 3.182
Total of 3 streams to confluence:

Flow rates before confluence point:

7.784 2.567 0.316
Maximum flow rates at confluence using above data:

9.194 5.475 3.182
Area of streams before confluence:

6.218 0.453 0.046
Results of confluence:

Total flow rate = 9.194(CFS)
Time of concentration = 19.816 min.

Effective stream area after confluence = 6.717(Ac.) End of computations, total study area = 6.717 (Ac.)

FINAL CALC POST DEVELOPMENT CONDITION
100 YEAR STORM EVENT

San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2004 Version 7.4 Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 02/09/09
------------------------------------------------------------------------ 08030 CVS PHARMACY
EXISTING + DEVELOPED CONDITIONS, FINAL FLOW CALC
100 YEAR STORM EVENT
MANUAL INPUT ON NODES 10,22,AND 25
------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** ------------------------------------------------------------------------ Program License Serial Number 4012
------------------------------------------------------------------------ Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 3.300
24 hour precipitation(inches) = 5.700
P6/P24 = 57.9%
San Diego hydrology manual 'C' values used
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 22.000 to Point/Station 22.000 **** USER DEFINED FLOW INFORMATION AT A POINT ****
______________________________________________________________________ Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Neighborhod Commercial )
Impervious value, Ai = 0.800
Sub-Area C Value = 0.790
Rainfall intensity (I) = 3.249(In/Hr) for a 100.0 year storm User specified values are as follows:

TC = 23.00 min. Rain intensity = 3.25(In/Hr)
Total area = 0.257(Ac.) Total runoff = 0.659(CFS) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 22.000 to Point/Station 20.000 **** PIPEFLOW TRAVEL TIME (User specified size) ****
______________________________________________________________________ Upstream point/station elevation = 564.020(Ft.)
Downstream point/station elevation = 563.950(Ft.)
Pipe length = 15.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 0.659(CFS)
Given pipe size = 12.00(In.)
Calculated individual pipe flow = 0.659(CFS)
Normal flow depth in pipe = 4.27(In.)
Flow top width inside pipe = 11.49(In.)
Critical Depth = 4.05(In.)
Pipe flow velocity = 2.63(Ft/s)
Travel time through pipe = 0.09 min.

Time of concentration (TC) = 23.09 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 20.000 to Point/Station 20.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________

FINAL CALC POST DEVELOPMENT CONDITION
100 YEAR STORM EVENT

Along Main Stream number: 1 in normal stream number 1
Stream flow area = 0.257(Ac.)
Runoff from this stream = 0.659(CFS)
Time of concentration = 23.09 min.

Rainfall intensity = 3.241(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 10.000 to Point/Station 10.000 **** USER DEFINED FLOW INFORMATION AT A POINT ****
______________________________________________________________________ User specified 'C' value of 0.600 given for subarea
Rainfall intensity (I) = 1.969(In/Hr) for a 100.0 year storm User specified values are as follows:

TC = 50.00 min. Rain intensity = 1.97(In/Hr)
Total area = 1.500(Ac.) Total runoff = 1.780(CFS) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 10.000 to Point/Station 20.000 **** PIPEFLOW TRAVEL TIME (User specified size) ****
______________________________________________________________________ Upstream point/station elevation = 564.700(Ft.)
Downstream point/station elevation = 563.950(Ft.)
Pipe length = 150.00(Ft.) Manning's N = 0.013
No. of pipes = 2 Required pipe flow = 1.780(CFS)
Given pipe size = 8.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.

The approximate hydraulic grade line above the pipe invert is

0.215(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 0.813(Ft.)
Minor friction loss = 0.151(Ft.) K-factor = 1.50 Pipe flow velocity = 2.55(Ft/s)
Travel time through pipe = 0.98 min.

Time of concentration (TC) = 50.98 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 20.000 to Point/Station 20.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2
Stream flow area = 1.500(Ac.)
Runoff from this stream = 1.780(CFS)
Time of concentration = 50.98 min.

Rainfall intensity = 1.945(In/Hr)
Summary of stream data:

Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr)
1 0.659 23.09 3.241
2 1.780 50.98 1.945
Qmax(1) =

1.000 * 1.000 * 0.659) +

1.000 * 0.453 * 1.780) + = 1.465
Qmax(2) =

0.600 * 1.000 * 0.659) +

1.000 * 1.000 * 1.780) + = 2.175
Total of 2 streams to confluence:

Flow rates before confluence point:

0.659 1.780
Maximum flow rates at confluence using above data:

1.465 2.175
Area of streams before confluence:

0.257 1.500
Results of confluence:

Total flow rate = 2.175(CFS)

FINAL CALC POST DEVELOPMENT CONDITION
100 YEAR STORM EVENT

Time of concentration = 50.981 min.

Effective stream area after confluence = 1.757(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 20.000 to Point/Station 3.000 **** PIPEFLOW TRAVEL TIME (User specified size) ****
______________________________________________________________________ Upstream point/station elevation = 563.900(Ft.)
Downstream point/station elevation = 562.840(Ft.)
Pipe length = 205.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 2.175(CFS)
Given pipe size = 12.00(In.)
Calculated individual pipe flow = 2.175(CFS)
Normal flow depth in pipe = 8.50(In.)
Flow top width inside pipe = 10.91(In.)
Critical Depth = 7.57(In.)
Pipe flow velocity = 3.66(Ft/s)
Travel time through pipe = 0.93 min.

Time of concentration (TC) = 51.91 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 3.000 to Point/Station 3.000 **** CONFLUENCE OF MAIN STREAMS ****
______________________________________________________________________ The following data inside Main Stream is listed:

In Main Stream number: 1
Stream flow area = 1.757(Ac.)
Runoff from this stream = 2.175(CFS)
Time of concentration = 51.91 min.

Rainfall intensity = 1.922(In/Hr)
Program is now starting with Main Stream No. 2
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 25.000 to Point/Station 25.000 **** USER DEFINED FLOW INFORMATION AT A POINT ****
______________________________________________________________________ User specified 'C' value of 0.410 given for subarea
Rainfall intensity (I) = 1.751(In/Hr) for a 100.0 year storm User specified values are as follows:

TC = 60.00 min. Rain intensity = 1.75(In/Hr)
Total area = 6.717(Ac.) Total runoff = 4.770(CFS) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 25.000 to Point/Station 3.000 **** PIPEFLOW TRAVEL TIME (User specified size) ****
______________________________________________________________________ Upstream point/station elevation = 564.630(Ft.)
Downstream point/station elevation = 562.840(Ft.)
Pipe length = 47.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 4.770(CFS)
Given pipe size = 12.00(In.)
Calculated individual pipe flow = 4.770(CFS)
Normal flow depth in pipe = 7.30(In.)
Flow top width inside pipe = 11.71(In.)
Critical Depth = 10.85(In.)
Pipe flow velocity = 9.54(Ft/s)
Travel time through pipe = 0.08 min.

Time of concentration (TC) = 60.08 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 3.000 to Point/Station 3.000 **** CONFLUENCE OF MAIN STREAMS ****
______________________________________________________________________ The following data inside Main Stream is listed:

In Main Stream number: 2
Stream flow area = 6.717(Ac.)

FINAL CALC POST DEVELOPMENT CONDITION
100 YEAR STORM EVENT

Runoff from this stream = 4.770(CFS)
Time of concentration = 60.08 min.

Rainfall intensity = 1.749(In/Hr)
Summary of stream data:

Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In/Hr)
1 2.175 51.91 1.922
2 4.770 60.08 1.749
Qmax(1) =

1.000 * 1.000 * 2.175) +

1.000 * 0.864 * 4.770) + = 6.297
Qmax(2) =

0.910 * 1.000 * 2.175) +

1.000 * 1.000 * 4.770) + = 6.750
Total of 2 main streams to confluence:

Flow rates before confluence point:

2.175 4.770
Maximum flow rates at confluence using above data:

6.297 6.750
Area of streams before confluence:

1.757 6.717
Results of confluence:

Total flow rate = 6.750(CFS)
Time of concentration = 60.082 min.

Effective stream area after confluence = 8.474(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 3.000 to Point/Station 26.000 **** PIPEFLOW TRAVEL TIME (User specified size) ****
______________________________________________________________________ Upstream point/station elevation = 562.840(Ft.)
Downstream point/station elevation = 561.820(Ft.)
Pipe length = 25.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 6.750(CFS)
Given pipe size = 12.00(In.)
Calculated individual pipe flow = 6.750(CFS)
Normal flow depth in pipe = 9.23(In.)
Flow top width inside pipe = 10.11(In.)
Critical depth could not be calculated.

Pipe flow velocity = 10.42(Ft/s)
Travel time through pipe = 0.04 min.

Time of concentration (TC) = 60.12 min.

End of computations, total study area = 8.474 (Ac.) Preliminary Drainage Study for Las Posas
RE:jk R:\1482\&Hyd\Hydrology\Report\1482- DR-Las Posas.doc w.o. 3087-0007
CHAPTER 4

HYDROLOGIC ANALYSIS
Developed Condition
Preliminary Drainage Study for Gran Vista
RE:jk R:\1482\&Hyd\Hydrology\Report\1482- DR-Las Posas.doc w.o. 3087-0007
RE:jk R:\1482\&Hyd\Hydrology\Report\1482- DR-Las Posas.doc w.o. 0061-0499
Preliminary Drainage Study for Las Posas
Developed Condition
100 – Year Design Storm
Preliminary Drainage Study for Gran Vista
RE:jk R:\1482\&Hyd\Hydrology\Report\1482- DR-Las Posas.doc w.o. 3087-0007
100.DOC
____________________________________________________________________________ ****************************************************************************

RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2015 Advanced Engineering Software (aes) Ver. 22.0 Release Date: 07/01/2015 License ID 1239
Analysis prepared by:
************************** DESCRIPTION OF STUDY ************************** * Las Posas * * 100-Year Proposed * * DLN 1482, W.O. #0025-0364 * ************************************************************************** FILE NAME: R:\1482\AES\100.DAT
TIME/DATE OF STUDY: 13:37 02/15/2022
---------------------------------------------------------------------------- USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
---------------------------------------------------------------------------- 2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 3.300
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n) === ===== ========= ================= ====== ===== ====== ===== ======= 1 16.0 8.0 0.020/0.020/0.020 0.50 2.00 0.0313 0.125 0.0150 2 12.0 6.0 0.020/0.020/0.020 0.50 1.50 0.0313 0.125 0.0130 3 12.0 6.0 0.020/0.020/ --- 0.33 1.50 0.0208 0.083 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
**************************************************************************** FLOW PROCESS FROM NODE 100.00 TO NODE 102.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 584.50
DOWNSTREAM ELEVATION(FEET) = 583.50
ELEVATION DIFFERENCE(FEET) = 1.00
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.660
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = 65.00
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.027
SUBAREA RUNOFF(CFS) = 0.57
TOTAL AREA(ACRES) = 0.10 TOTAL RUNOFF(CFS) = 0.57 ****************************************************************************

100.DOC
FLOW PROCESS FROM NODE 102.00 TO NODE 104.00 IS CODE = 62 ---------------------------------------------------------------------------- >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 3 USED)<<<<<
============================================================================ UPSTREAM ELEVATION(FEET) = 583.10 DOWNSTREAM ELEVATION(FEET) = 579.00 STREET LENGTH(FEET) = 459.00 CURB HEIGHT(INCHES) = 4.0 STREET HALFWIDTH(FEET) = 12.00
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 6.00 INSIDE STREET CROSSFALL(DECIMAL) = 0.020
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.020
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 2
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150 **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.55 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:

STREET FLOW DEPTH(FEET) = 0.23
HALFSTREET FLOOD WIDTH(FEET) = 7.92
AVERAGE FLOW VELOCITY(FEET/SEC.) = 1.83
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.42
STREET FLOW TRAVEL TIME(MIN.) = 4.19 Tc(MIN.) = 9.85 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.615
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
AREA-AVERAGE RUNOFF COEFFICIENT = 0.710
SUBAREA AREA(ACRES) = 0.98 SUBAREA RUNOFF(CFS) = 3.91 TOTAL AREA(ACRES) = 1.1 PEAK FLOW RATE(CFS) = 4.31 END OF SUBAREA STREET FLOW HYDRAULICS:

DEPTH(FEET) = 0.27 HALFSTREET FLOOD WIDTH(FEET) = 9.89 FLOW VELOCITY(FEET/SEC.) = 2.05 DEPTH*VELOCITY(FT*FT/SEC.) = 0.56 LONGEST FLOWPATH FROM NODE 100.00 TO NODE 104.00 = 559.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 106.00 TO NODE 104.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.615
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
AREA-AVERAGE RUNOFF COEFFICIENT = 0.7100
SUBAREA AREA(ACRES) = 0.45 SUBAREA RUNOFF(CFS) = 1.79 TOTAL AREA(ACRES) = 1.5 TOTAL RUNOFF(CFS) = 6.10 TC(MIN.) = 9.85
**************************************************************************** FLOW PROCESS FROM NODE 104.00 TO NODE 108.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 570.80 DOWNSTREAM(FEET) = 569.70 FLOW LENGTH(FEET) = 266.30 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 13.7 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.23
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.10
PIPE TRAVEL TIME(MIN.) = 1.05 Tc(MIN.) = 10.90
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 108.00 = 825.30 FEET. **************************************************************************** FLOW PROCESS FROM NODE 108.00 TO NODE 108.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 10.90

100.DOC
RAINFALL INTENSITY(INCH/HR) = 5.26
TOTAL STREAM AREA(ACRES) = 1.53
PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.10
**************************************************************************** FLOW PROCESS FROM NODE 110.00 TO NODE 112.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 580.80
DOWNSTREAM ELEVATION(FEET) = 579.22
ELEVATION DIFFERENCE(FEET) = 1.58
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.072
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = 70.80
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.615
SUBAREA RUNOFF(CFS) = 0.61
TOTAL AREA(ACRES) = 0.10 TOTAL RUNOFF(CFS) = 0.61 **************************************************************************** FLOW PROCESS FROM NODE 112.00 TO NODE 108.00 IS CODE = 62 ---------------------------------------------------------------------------- >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 3 USED)<<<<<
============================================================================ UPSTREAM ELEVATION(FEET) = 579.22 DOWNSTREAM ELEVATION(FEET) = 576.40 STREET LENGTH(FEET) = 292.00 CURB HEIGHT(INCHES) = 4.0 STREET HALFWIDTH(FEET) = 12.00
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 6.00 INSIDE STREET CROSSFALL(DECIMAL) = 0.020
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.020
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 2
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150 **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.32 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:

STREET FLOW DEPTH(FEET) = 0.25
HALFSTREET FLOOD WIDTH(FEET) = 8.77
AVERAGE FLOW VELOCITY(FEET/SEC.) = 1.98
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.49
STREET FLOW TRAVEL TIME(MIN.) = 2.46 Tc(MIN.) = 7.53 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.674
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
AREA-AVERAGE RUNOFF COEFFICIENT = 0.710
SUBAREA AREA(ACRES) = 1.13 SUBAREA RUNOFF(CFS) = 5.35 TOTAL AREA(ACRES) = 1.2 PEAK FLOW RATE(CFS) = 5.83 END OF SUBAREA STREET FLOW HYDRAULICS:

DEPTH(FEET) = 0.29 HALFSTREET FLOOD WIDTH(FEET) = 11.02 FLOW VELOCITY(FEET/SEC.) = 2.27 DEPTH*VELOCITY(FT*FT/SEC.) = 0.67 LONGEST FLOWPATH FROM NODE 110.00 TO NODE 108.00 = 392.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 108.00 TO NODE 108.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 7.53
RAINFALL INTENSITY(INCH/HR) = 6.67
TOTAL STREAM AREA(ACRES) = 1.23

100.DOC
PEAK FLOW RATE(CFS) AT CONFLUENCE = 5.83
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 6.10 10.90 5.260 1.53
2 5.83 7.53 6.674 1.23

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 10.04 7.53 6.674
2 10.69 10.90 5.260
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 10.69 Tc(MIN.) = 10.90
TOTAL AREA(ACRES) = 2.8
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 108.00 = 825.30 FEET. **************************************************************************** FLOW PROCESS FROM NODE 114.00 TO NODE 108.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.260
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
AREA-AVERAGE RUNOFF COEFFICIENT = 0.7100
SUBAREA AREA(ACRES) = 0.84 SUBAREA RUNOFF(CFS) = 3.14 TOTAL AREA(ACRES) = 3.6 TOTAL RUNOFF(CFS) = 13.44 TC(MIN.) = 10.90
**************************************************************************** FLOW PROCESS FROM NODE 108.00 TO NODE 118.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 567.50 DOWNSTREAM(FEET) = 566.41 FLOW LENGTH(FEET) = 38.26 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 11.9 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 10.81
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 13.44
PIPE TRAVEL TIME(MIN.) = 0.06 Tc(MIN.) = 10.96
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 118.00 = 863.56 FEET. **************************************************************************** FLOW PROCESS FROM NODE 118.00 TO NODE 118.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 10.96
RAINFALL INTENSITY(INCH/HR) = 5.24
TOTAL STREAM AREA(ACRES) = 3.60
PEAK FLOW RATE(CFS) AT CONFLUENCE = 13.44
**************************************************************************** FLOW PROCESS FROM NODE 115.00 TO NODE 116.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 574.20

100.DOC
DOWNSTREAM ELEVATION(FEET) = 574.00
ELEVATION DIFFERENCE(FEET) = 0.20
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 6.254
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = 50.00
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.526
SUBAREA RUNOFF(CFS) = 0.64
TOTAL AREA(ACRES) = 0.12 TOTAL RUNOFF(CFS) = 0.64 **************************************************************************** FLOW PROCESS FROM NODE 116.00 TO NODE 118.00 IS CODE = 51 ---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 573.70 DOWNSTREAM(FEET) = 572.70 CHANNEL LENGTH THRU SUBAREA(FEET) = 106.00 CHANNEL SLOPE = 0.0094 CHANNEL BASE(FEET) = 0.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 0.50 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.761
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.41 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.56 AVERAGE FLOW DEPTH(FEET) = 0.13 TRAVEL TIME(MIN.) = 1.13 Tc(MIN.) = 7.38
SUBAREA AREA(ACRES) = 0.32 SUBAREA RUNOFF(CFS) = 1.54 AREA-AVERAGE RUNOFF COEFFICIENT = 0.710
TOTAL AREA(ACRES) = 0.4 PEAK FLOW RATE(CFS) = 2.11 END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.16 FLOW VELOCITY(FEET/SEC.) = 1.75 LONGEST FLOWPATH FROM NODE 115.00 TO NODE 118.00 = 206.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 118.00 TO NODE 118.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 7.38
RAINFALL INTENSITY(INCH/HR) = 6.76
TOTAL STREAM AREA(ACRES) = 0.44
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.11
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 13.44 10.96 5.242 3.60
2 2.11 7.38 6.761 0.44

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 12.53 7.38 6.761
2 15.08 10.96 5.242
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 15.08 Tc(MIN.) = 10.96
TOTAL AREA(ACRES) = 4.0
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 118.00 = 863.56 FEET. **************************************************************************** FLOW PROCESS FROM NODE 118.00 TO NODE 119.00 IS CODE = 31 ----------------------------------------------------------------------------

100.DOC
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 566.41 DOWNSTREAM(FEET) = 564.70 FLOW LENGTH(FEET) = 300.13 MANNING'S N = 0.013
DEPTH OF FLOW IN 24.0 INCH PIPE IS 17.9 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.00
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 15.08
PIPE TRAVEL TIME(MIN.) = 0.83 Tc(MIN.) = 11.79
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 119.00 = 1163.69 FEET. **************************************************************************** FLOW PROCESS FROM NODE 119.00 TO NODE 119.00 IS CODE = 10 ---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 2 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 200.00 TO NODE 202.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 579.50
DOWNSTREAM ELEVATION(FEET) = 578.50
ELEVATION DIFFERENCE(FEET) = 1.00
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.660
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = 65.00
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.027
SUBAREA RUNOFF(CFS) = 0.57
TOTAL AREA(ACRES) = 0.10 TOTAL RUNOFF(CFS) = 0.57 **************************************************************************** FLOW PROCESS FROM NODE 202.00 TO NODE 204.00 IS CODE = 62 ---------------------------------------------------------------------------- >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 3 USED)<<<<<
============================================================================ UPSTREAM ELEVATION(FEET) = 578.50 DOWNSTREAM ELEVATION(FEET) = 573.60 STREET LENGTH(FEET) = 440.00 CURB HEIGHT(INCHES) = 4.0 STREET HALFWIDTH(FEET) = 12.00
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 6.00 INSIDE STREET CROSSFALL(DECIMAL) = 0.020
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.020
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 2
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150 **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.51 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:

STREET FLOW DEPTH(FEET) = 0.25
HALFSTREET FLOOD WIDTH(FEET) = 8.67
AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.13
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.53
STREET FLOW TRAVEL TIME(MIN.) = 3.44 Tc(MIN.) = 9.10 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.908
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
AREA-AVERAGE RUNOFF COEFFICIENT = 0.710
SUBAREA AREA(ACRES) = 1.38 SUBAREA RUNOFF(CFS) = 5.79 TOTAL AREA(ACRES) = 1.5 PEAK FLOW RATE(CFS) = 6.21 END OF SUBAREA STREET FLOW HYDRAULICS:

DEPTH(FEET) = 0.29 HALFSTREET FLOOD WIDTH(FEET) = 10.92

100.DOC
FLOW VELOCITY(FEET/SEC.) = 2.46 DEPTH*VELOCITY(FT*FT/SEC.) = 0.72 LONGEST FLOWPATH FROM NODE 200.00 TO NODE 204.00 = 540.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 206.00 TO NODE 204.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.908
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
AREA-AVERAGE RUNOFF COEFFICIENT = 0.7100
SUBAREA AREA(ACRES) = 0.44 SUBAREA RUNOFF(CFS) = 1.85 TOTAL AREA(ACRES) = 1.9 TOTAL RUNOFF(CFS) = 8.05 TC(MIN.) = 9.10
**************************************************************************** FLOW PROCESS FROM NODE 204.00 TO NODE 119.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 565.50 DOWNSTREAM(FEET) = 564.90 FLOW LENGTH(FEET) = 25.00 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 9.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 9.01
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 8.05
PIPE TRAVEL TIME(MIN.) = 0.05 Tc(MIN.) = 9.15
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 119.00 = 565.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 119.00 TO NODE 119.00 IS CODE = 11 ---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 2 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 8.05 9.15 5.888 1.92
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 119.00 = 565.00 FEET. ** MEMORY BANK # 2 CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 15.08 11.79 5.000 4.04
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 119.00 = 1163.69 FEET. ** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 19.76 9.15 5.888
2 21.92 11.79 5.000
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 21.92 Tc(MIN.) = 11.79
TOTAL AREA(ACRES) = 6.0
**************************************************************************** FLOW PROCESS FROM NODE 119.00 TO NODE 119.00 IS CODE = 12 ---------------------------------------------------------------------------- >>>>>CLEAR MEMORY BANK # 2 <<<<<
============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 119.00 TO NODE 120.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================

100.DOC
ELEVATION DATA: UPSTREAM(FEET) = 564.90 DOWNSTREAM(FEET) = 564.50 FLOW LENGTH(FEET) = 26.93 MANNING'S N = 0.013
DEPTH OF FLOW IN 24.0 INCH PIPE IS 16.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 9.54
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 21.92
PIPE TRAVEL TIME(MIN.) = 0.05 Tc(MIN.) = 11.84
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 1190.62 FEET. **************************************************************************** FLOW PROCESS FROM NODE 120.00 TO NODE 120.00 IS CODE = 10 ---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 2 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 25.00 TO NODE 25.00 IS CODE = 7 ---------------------------------------------------------------------------- >>>>>USER SPECIFIED HYDROLOGY INFORMATION AT NODE<<<<<
============================================================================ USER-SPECIFIED VALUES ARE AS FOLLOWS:

TC(MIN) = 6.74 RAIN INTENSITY(INCH/HOUR) = 7.17
TOTAL AREA(ACRES) = 0.45 TOTAL RUNOFF(CFS) = 2.57 +--------------------------------------------------------------------------+ | | | The following Code 8 is the driveway and sidewalk drain towards the | | exisitng drive | +--------------------------------------------------------------------------+ **************************************************************************** FLOW PROCESS FROM NODE 25.00 TO NODE 25.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.171
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (14.5 DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0
AREA-AVERAGE RUNOFF COEFFICIENT = 0.7769
SUBAREA AREA(ACRES) = 0.09 SUBAREA RUNOFF(CFS) = 0.46 TOTAL AREA(ACRES) = 0.5 TOTAL RUNOFF(CFS) = 3.03 TC(MIN.) = 6.74
**************************************************************************** FLOW PROCESS FROM NODE 25.00 TO NODE 20.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 565.50 DOWNSTREAM(FEET) = 563.95 FLOW LENGTH(FEET) = 105.00 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 6.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.81
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 3.03
PIPE TRAVEL TIME(MIN.) = 0.30 Tc(MIN.) = 7.04
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 20.00 = 1295.62 FEET. **************************************************************************** FLOW PROCESS FROM NODE 20.00 TO NODE 20.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.04
RAINFALL INTENSITY(INCH/HR) = 6.97
TOTAL STREAM AREA(ACRES) = 0.54
PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.03
****************************************************************************

100.DOC
FLOW PROCESS FROM NODE 20.00 TO NODE 20.00 IS CODE = 7 ---------------------------------------------------------------------------- >>>>>USER SPECIFIED HYDROLOGY INFORMATION AT NODE<<<<<
============================================================================ USER-SPECIFIED VALUES ARE AS FOLLOWS:

TC(MIN) = 50.98 RAIN INTENSITY(INCH/HOUR) = 1.94
TOTAL AREA(ACRES) = 1.76 TOTAL RUNOFF(CFS) = 2.17 **************************************************************************** FLOW PROCESS FROM NODE 20.00 TO NODE 20.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 50.98
RAINFALL INTENSITY(INCH/HR) = 1.94
TOTAL STREAM AREA(ACRES) = 1.76
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.17
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 3.03 7.04 6.972 0.54
2 2.17 50.98 1.945 1.76

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 3.33 7.04 6.972
2 3.02 50.98 1.945
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 3.33 Tc(MIN.) = 7.04
TOTAL AREA(ACRES) = 2.3
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 20.00 = 1295.62 FEET. **************************************************************************** FLOW PROCESS FROM NODE 20.00 TO NODE 120.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 563.90 DOWNSTREAM(FEET) = 562.84 FLOW LENGTH(FEET) = 205.00 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 8.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.06
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 3.33
PIPE TRAVEL TIME(MIN.) = 0.84 Tc(MIN.) = 7.88
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 1500.62 FEET. **************************************************************************** FLOW PROCESS FROM NODE 120.00 TO NODE 120.00 IS CODE = 11 ---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 2 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 3.33 7.88 6.482 2.30
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 1500.62 FEET. ** MEMORY BANK # 2 CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 21.92 11.84 4.987 5.96

100.DOC
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 1190.62 FEET. ** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 17.92 7.88 6.482
2 24.48 11.84 4.987
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 24.48 Tc(MIN.) = 11.84
TOTAL AREA(ACRES) = 8.3
**************************************************************************** FLOW PROCESS FROM NODE 120.00 TO NODE 120.00 IS CODE = 12 ---------------------------------------------------------------------------- >>>>>CLEAR MEMORY BANK # 2 <<<<<
============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 120.00 TO NODE 1.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 564.50 DOWNSTREAM(FEET) = 564.30 FLOW LENGTH(FEET) = 25.30 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 20.3 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.65
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 24.48
PIPE TRAVEL TIME(MIN.) = 0.06 Tc(MIN.) = 11.89
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 1.00 = 1525.92 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 8.3 TC(MIN.) = 11.89 PEAK FLOW RATE(CFS) = 24.48
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

Developed Condition
100 – Year Design Storm
Mitigated Flow
Preliminary Drainage Study for Gran Vista
RE:jk R:\1482\&Hyd\Hydrology\Report\1482- DR-Las Posas.doc w.o. 3087-0007
100.DOC
____________________________________________________________________________ ****************************************************************************

RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2015 Advanced Engineering Software (aes) Ver. 22.0 Release Date: 07/01/2015 License ID 1239
Analysis prepared by:
************************** DESCRIPTION OF STUDY ************************** * Las Posas * * 100-Year Proposed * * DLN 1482, W.O. #0025-0364 * ************************************************************************** FILE NAME: R:\1482\AES\MIT\100.DAT
TIME/DATE OF STUDY: 15:46 02/16/2022
---------------------------------------------------------------------------- USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
---------------------------------------------------------------------------- 2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 3.300
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n) === ===== ========= ================= ====== ===== ====== ===== ======= 1 16.0 8.0 0.020/0.020/0.020 0.50 2.00 0.0313 0.125 0.0150 2 12.0 6.0 0.020/0.020/0.020 0.50 1.50 0.0313 0.125 0.0130 3 12.0 6.0 0.020/0.020/ --- 0.33 1.50 0.0208 0.083 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
**************************************************************************** FLOW PROCESS FROM NODE 100.00 TO NODE 102.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 584.50
DOWNSTREAM ELEVATION(FEET) = 583.50
ELEVATION DIFFERENCE(FEET) = 1.00
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.660
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = 65.00
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.027
SUBAREA RUNOFF(CFS) = 0.57
TOTAL AREA(ACRES) = 0.10 TOTAL RUNOFF(CFS) = 0.57 ****************************************************************************

100.DOC
FLOW PROCESS FROM NODE 102.00 TO NODE 104.00 IS CODE = 62 ---------------------------------------------------------------------------- >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 3 USED)<<<<<
============================================================================ UPSTREAM ELEVATION(FEET) = 583.10 DOWNSTREAM ELEVATION(FEET) = 579.00 STREET LENGTH(FEET) = 459.00 CURB HEIGHT(INCHES) = 4.0 STREET HALFWIDTH(FEET) = 12.00
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 6.00 INSIDE STREET CROSSFALL(DECIMAL) = 0.020
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.020
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 2
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150 **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.55 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:

STREET FLOW DEPTH(FEET) = 0.23
HALFSTREET FLOOD WIDTH(FEET) = 7.92
AVERAGE FLOW VELOCITY(FEET/SEC.) = 1.83
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.42
STREET FLOW TRAVEL TIME(MIN.) = 4.19 Tc(MIN.) = 9.85 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.615
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
AREA-AVERAGE RUNOFF COEFFICIENT = 0.710
SUBAREA AREA(ACRES) = 0.98 SUBAREA RUNOFF(CFS) = 3.91 TOTAL AREA(ACRES) = 1.1 PEAK FLOW RATE(CFS) = 4.31 END OF SUBAREA STREET FLOW HYDRAULICS:

DEPTH(FEET) = 0.27 HALFSTREET FLOOD WIDTH(FEET) = 9.89 FLOW VELOCITY(FEET/SEC.) = 2.05 DEPTH*VELOCITY(FT*FT/SEC.) = 0.56 LONGEST FLOWPATH FROM NODE 100.00 TO NODE 104.00 = 559.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 106.00 TO NODE 104.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.615
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
AREA-AVERAGE RUNOFF COEFFICIENT = 0.7100
SUBAREA AREA(ACRES) = 0.45 SUBAREA RUNOFF(CFS) = 1.79 TOTAL AREA(ACRES) = 1.5 TOTAL RUNOFF(CFS) = 6.10 TC(MIN.) = 9.85
**************************************************************************** FLOW PROCESS FROM NODE 104.00 TO NODE 108.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 570.80 DOWNSTREAM(FEET) = 569.70 FLOW LENGTH(FEET) = 266.30 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 13.7 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.23
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.10
PIPE TRAVEL TIME(MIN.) = 1.05 Tc(MIN.) = 10.90
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 108.00 = 825.30 FEET. **************************************************************************** FLOW PROCESS FROM NODE 108.00 TO NODE 108.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 10.90

100.DOC
RAINFALL INTENSITY(INCH/HR) = 5.26
TOTAL STREAM AREA(ACRES) = 1.53
PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.10
**************************************************************************** FLOW PROCESS FROM NODE 110.00 TO NODE 112.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 580.80
DOWNSTREAM ELEVATION(FEET) = 579.22
ELEVATION DIFFERENCE(FEET) = 1.58
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.072
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = 70.80
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.615
SUBAREA RUNOFF(CFS) = 0.61
TOTAL AREA(ACRES) = 0.10 TOTAL RUNOFF(CFS) = 0.61 **************************************************************************** FLOW PROCESS FROM NODE 112.00 TO NODE 108.00 IS CODE = 62 ---------------------------------------------------------------------------- >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 3 USED)<<<<<
============================================================================ UPSTREAM ELEVATION(FEET) = 579.22 DOWNSTREAM ELEVATION(FEET) = 576.40 STREET LENGTH(FEET) = 292.00 CURB HEIGHT(INCHES) = 4.0 STREET HALFWIDTH(FEET) = 12.00
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 6.00 INSIDE STREET CROSSFALL(DECIMAL) = 0.020
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.020
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 2
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150 **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.32 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:

STREET FLOW DEPTH(FEET) = 0.25
HALFSTREET FLOOD WIDTH(FEET) = 8.77
AVERAGE FLOW VELOCITY(FEET/SEC.) = 1.98
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.49
STREET FLOW TRAVEL TIME(MIN.) = 2.46 Tc(MIN.) = 7.53 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.674
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
AREA-AVERAGE RUNOFF COEFFICIENT = 0.710
SUBAREA AREA(ACRES) = 1.13 SUBAREA RUNOFF(CFS) = 5.35 TOTAL AREA(ACRES) = 1.2 PEAK FLOW RATE(CFS) = 5.83 END OF SUBAREA STREET FLOW HYDRAULICS:

DEPTH(FEET) = 0.29 HALFSTREET FLOOD WIDTH(FEET) = 11.02 FLOW VELOCITY(FEET/SEC.) = 2.27 DEPTH*VELOCITY(FT*FT/SEC.) = 0.67 LONGEST FLOWPATH FROM NODE 110.00 TO NODE 108.00 = 392.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 108.00 TO NODE 108.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 7.53
RAINFALL INTENSITY(INCH/HR) = 6.67
TOTAL STREAM AREA(ACRES) = 1.23

100.DOC
PEAK FLOW RATE(CFS) AT CONFLUENCE = 5.83
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 6.10 10.90 5.260 1.53
2 5.83 7.53 6.674 1.23

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 10.04 7.53 6.674
2 10.69 10.90 5.260
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 10.69 Tc(MIN.) = 10.90
TOTAL AREA(ACRES) = 2.8
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 108.00 = 825.30 FEET. **************************************************************************** FLOW PROCESS FROM NODE 114.00 TO NODE 108.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.260
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
AREA-AVERAGE RUNOFF COEFFICIENT = 0.7100
SUBAREA AREA(ACRES) = 0.84 SUBAREA RUNOFF(CFS) = 3.14 TOTAL AREA(ACRES) = 3.6 TOTAL RUNOFF(CFS) = 13.44 TC(MIN.) = 10.90
+--------------------------------------------------------------------------+ | The following code 7 from detention analysis for Vault 2 at Node 108 | | See chapter 5 for detention Analysis | | | +--------------------------------------------------------------------------+ **************************************************************************** FLOW PROCESS FROM NODE 108.00 TO NODE 108.00 IS CODE = 7 ---------------------------------------------------------------------------- >>>>>USER SPECIFIED HYDROLOGY INFORMATION AT NODE<<<<<
============================================================================ USER-SPECIFIED VALUES ARE AS FOLLOWS:

TC(MIN) = 19.90 RAIN INTENSITY(INCH/HOUR) = 3.57
TOTAL AREA(ACRES) = 3.60 TOTAL RUNOFF(CFS) = 5.85 **************************************************************************** FLOW PROCESS FROM NODE 108.00 TO NODE 118.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 567.50 DOWNSTREAM(FEET) = 566.41 FLOW LENGTH(FEET) = 38.26 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 7.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.83
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 5.85
PIPE TRAVEL TIME(MIN.) = 0.07 Tc(MIN.) = 19.97
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 118.00 = 863.56 FEET. **************************************************************************** FLOW PROCESS FROM NODE 118.00 TO NODE 118.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2

100.DOC
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 19.97
RAINFALL INTENSITY(INCH/HR) = 3.56
TOTAL STREAM AREA(ACRES) = 3.60
PEAK FLOW RATE(CFS) AT CONFLUENCE = 5.85
**************************************************************************** FLOW PROCESS FROM NODE 115.00 TO NODE 116.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 574.20
DOWNSTREAM ELEVATION(FEET) = 574.00
ELEVATION DIFFERENCE(FEET) = 0.20
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 6.254
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = 50.00
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.526
SUBAREA RUNOFF(CFS) = 0.64
TOTAL AREA(ACRES) = 0.12 TOTAL RUNOFF(CFS) = 0.64 **************************************************************************** FLOW PROCESS FROM NODE 116.00 TO NODE 118.00 IS CODE = 51 ---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 573.70 DOWNSTREAM(FEET) = 572.70 CHANNEL LENGTH THRU SUBAREA(FEET) = 106.00 CHANNEL SLOPE = 0.0094 CHANNEL BASE(FEET) = 0.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 0.50 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.761
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.41 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.56 AVERAGE FLOW DEPTH(FEET) = 0.13 TRAVEL TIME(MIN.) = 1.13 Tc(MIN.) = 7.38
SUBAREA AREA(ACRES) = 0.32 SUBAREA RUNOFF(CFS) = 1.54 AREA-AVERAGE RUNOFF COEFFICIENT = 0.710
TOTAL AREA(ACRES) = 0.4 PEAK FLOW RATE(CFS) = 2.11 END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.16 FLOW VELOCITY(FEET/SEC.) = 1.75 LONGEST FLOWPATH FROM NODE 115.00 TO NODE 118.00 = 206.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 118.00 TO NODE 118.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 7.38
RAINFALL INTENSITY(INCH/HR) = 6.76
TOTAL STREAM AREA(ACRES) = 0.44
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.11
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 5.85 19.97 3.559 3.60
2 2.11 7.38 6.761 0.44

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO

100.DOC
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 4.28 7.38 6.761
2 6.96 19.97 3.559
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 6.96 Tc(MIN.) = 19.97
TOTAL AREA(ACRES) = 4.0
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 118.00 = 863.56 FEET. **************************************************************************** FLOW PROCESS FROM NODE 118.00 TO NODE 119.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 566.41 DOWNSTREAM(FEET) = 564.70 FLOW LENGTH(FEET) = 300.13 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 13.4 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.95
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.96
PIPE TRAVEL TIME(MIN.) = 1.01 Tc(MIN.) = 20.98
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 119.00 = 1163.69 FEET. **************************************************************************** FLOW PROCESS FROM NODE 119.00 TO NODE 119.00 IS CODE = 10 ---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 2 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 200.00 TO NODE 202.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 579.50
DOWNSTREAM ELEVATION(FEET) = 578.50
ELEVATION DIFFERENCE(FEET) = 1.00
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.660
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = 65.00
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.027
SUBAREA RUNOFF(CFS) = 0.57
TOTAL AREA(ACRES) = 0.10 TOTAL RUNOFF(CFS) = 0.57 **************************************************************************** FLOW PROCESS FROM NODE 202.00 TO NODE 204.00 IS CODE = 62 ---------------------------------------------------------------------------- >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 3 USED)<<<<<
============================================================================ UPSTREAM ELEVATION(FEET) = 578.50 DOWNSTREAM ELEVATION(FEET) = 573.60 STREET LENGTH(FEET) = 440.00 CURB HEIGHT(INCHES) = 4.0 STREET HALFWIDTH(FEET) = 12.00
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 6.00 INSIDE STREET CROSSFALL(DECIMAL) = 0.020
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.020
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 2
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150 **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.51

100.DOC
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:

STREET FLOW DEPTH(FEET) = 0.25
HALFSTREET FLOOD WIDTH(FEET) = 8.67
AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.13
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.53
STREET FLOW TRAVEL TIME(MIN.) = 3.44 Tc(MIN.) = 9.10 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.908
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
AREA-AVERAGE RUNOFF COEFFICIENT = 0.710
SUBAREA AREA(ACRES) = 1.38 SUBAREA RUNOFF(CFS) = 5.79 TOTAL AREA(ACRES) = 1.5 PEAK FLOW RATE(CFS) = 6.21 END OF SUBAREA STREET FLOW HYDRAULICS:

DEPTH(FEET) = 0.29 HALFSTREET FLOOD WIDTH(FEET) = 10.92 FLOW VELOCITY(FEET/SEC.) = 2.46 DEPTH*VELOCITY(FT*FT/SEC.) = 0.72 LONGEST FLOWPATH FROM NODE 200.00 TO NODE 204.00 = 540.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 206.00 TO NODE 204.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.908
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (24. DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
AREA-AVERAGE RUNOFF COEFFICIENT = 0.7100
SUBAREA AREA(ACRES) = 0.44 SUBAREA RUNOFF(CFS) = 1.85 TOTAL AREA(ACRES) = 1.9 TOTAL RUNOFF(CFS) = 8.05 TC(MIN.) = 9.10
+--------------------------------------------------------------------------+ | the following code 7 is from detention analysis for Vault 1 | | see chapter 5 for detention analysis | | | +--------------------------------------------------------------------------+ **************************************************************************** FLOW PROCESS FROM NODE 204.00 TO NODE 204.00 IS CODE = 7 ---------------------------------------------------------------------------- >>>>>USER SPECIFIED HYDROLOGY INFORMATION AT NODE<<<<<
============================================================================ USER-SPECIFIED VALUES ARE AS FOLLOWS:

TC(MIN) = 17.10 RAIN INTENSITY(INCH/HOUR) = 3.93
TOTAL AREA(ACRES) = 1.90 TOTAL RUNOFF(CFS) = 2.79 **************************************************************************** FLOW PROCESS FROM NODE 204.00 TO NODE 119.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 565.50 DOWNSTREAM(FEET) = 564.90 FLOW LENGTH(FEET) = 25.00 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 5.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.76
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 2.79
PIPE TRAVEL TIME(MIN.) = 0.06 Tc(MIN.) = 17.16
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 119.00 = 565.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 119.00 TO NODE 119.00 IS CODE = 11 ---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 2 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)

100.DOC
1 2.79 17.16 3.925 1.90
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 119.00 = 565.00 FEET. ** MEMORY BANK # 2 CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 6.96 20.98 3.447 4.04
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 119.00 = 1163.69 FEET. ** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 8.48 17.16 3.925
2 9.41 20.98 3.447
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 9.41 Tc(MIN.) = 20.98
TOTAL AREA(ACRES) = 5.9
**************************************************************************** FLOW PROCESS FROM NODE 119.00 TO NODE 119.00 IS CODE = 12 ---------------------------------------------------------------------------- >>>>>CLEAR MEMORY BANK # 2 <<<<<
============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 119.00 TO NODE 120.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 564.90 DOWNSTREAM(FEET) = 564.50 FLOW LENGTH(FEET) = 26.93 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 11.7 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.76
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 9.41
PIPE TRAVEL TIME(MIN.) = 0.06 Tc(MIN.) = 21.04
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 1190.62 FEET. **************************************************************************** FLOW PROCESS FROM NODE 120.00 TO NODE 120.00 IS CODE = 10 ---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 2 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 25.00 TO NODE 25.00 IS CODE = 7 ---------------------------------------------------------------------------- >>>>>USER SPECIFIED HYDROLOGY INFORMATION AT NODE<<<<<
============================================================================ USER-SPECIFIED VALUES ARE AS FOLLOWS:

TC(MIN) = 6.74 RAIN INTENSITY(INCH/HOUR) = 7.17
TOTAL AREA(ACRES) = 0.45 TOTAL RUNOFF(CFS) = 2.57 +--------------------------------------------------------------------------+ | | | The following Code 8 is the driveway and sidewalk drain towards the | | exisitng drive | +--------------------------------------------------------------------------+ **************************************************************************** FLOW PROCESS FROM NODE 25.00 TO NODE 25.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.171
*USER SPECIFIED(SUBAREA):

RESIDENTIAL (14.5 DU/AC OR LESS) RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 93
AREA-AVERAGE RUNOFF COEFFICIENT = 0.7769
SUBAREA AREA(ACRES) = 0.09 SUBAREA RUNOFF(CFS) = 0.46 TOTAL AREA(ACRES) = 0.5 TOTAL RUNOFF(CFS) = 3.03

100.DOC
TC(MIN.) = 6.74
**************************************************************************** FLOW PROCESS FROM NODE 25.00 TO NODE 20.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 565.50 DOWNSTREAM(FEET) = 563.95 FLOW LENGTH(FEET) = 105.00 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 6.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.81
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 3.03
PIPE TRAVEL TIME(MIN.) = 0.30 Tc(MIN.) = 7.04
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 20.00 = 1295.62 FEET. **************************************************************************** FLOW PROCESS FROM NODE 20.00 TO NODE 20.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.04
RAINFALL INTENSITY(INCH/HR) = 6.97
TOTAL STREAM AREA(ACRES) = 0.54
PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.03
**************************************************************************** FLOW PROCESS FROM NODE 20.00 TO NODE 20.00 IS CODE = 7 ---------------------------------------------------------------------------- >>>>>USER SPECIFIED HYDROLOGY INFORMATION AT NODE<<<<<
============================================================================ USER-SPECIFIED VALUES ARE AS FOLLOWS:

TC(MIN) = 50.98 RAIN INTENSITY(INCH/HOUR) = 1.94
TOTAL AREA(ACRES) = 1.76 TOTAL RUNOFF(CFS) = 2.17 **************************************************************************** FLOW PROCESS FROM NODE 20.00 TO NODE 20.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 50.98
RAINFALL INTENSITY(INCH/HR) = 1.94
TOTAL STREAM AREA(ACRES) = 1.76
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.17
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 3.03 7.04 6.972 0.54
2 2.17 50.98 1.945 1.76

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 3.33 7.04 6.972
2 3.02 50.98 1.945
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 3.33 Tc(MIN.) = 7.04
TOTAL AREA(ACRES) = 2.3
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 20.00 = 1295.62 FEET. ****************************************************************************

100.DOC
FLOW PROCESS FROM NODE 20.00 TO NODE 120.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 563.90 DOWNSTREAM(FEET) = 562.84 FLOW LENGTH(FEET) = 205.00 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 8.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.06
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 3.33
PIPE TRAVEL TIME(MIN.) = 0.84 Tc(MIN.) = 7.88
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 1500.62 FEET. **************************************************************************** FLOW PROCESS FROM NODE 120.00 TO NODE 120.00 IS CODE = 11 ---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 2 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 3.33 7.88 6.482 2.30
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 1500.62 FEET. ** MEMORY BANK # 2 CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 9.41 21.04 3.441 5.94
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 1190.62 FEET. ** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 6.85 7.88 6.482
2 11.18 21.04 3.441
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 11.18 Tc(MIN.) = 21.04
TOTAL AREA(ACRES) = 8.2
**************************************************************************** FLOW PROCESS FROM NODE 120.00 TO NODE 120.00 IS CODE = 12 ---------------------------------------------------------------------------- >>>>>CLEAR MEMORY BANK # 2 <<<<<
============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 120.00 TO NODE 1.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 564.50 DOWNSTREAM(FEET) = 564.30 FLOW LENGTH(FEET) = 25.30 MANNING'S N = 0.013
DEPTH OF FLOW IN 21.0 INCH PIPE IS 14.4 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.36
ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 11.18
PIPE TRAVEL TIME(MIN.) = 0.07 Tc(MIN.) = 21.11
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 1.00 = 1525.92 FEET. ============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS
Preliminary Drainage Study for Gran vista
RE:jk R:\1482\&Hyd\Hydrology\Report\1482- DR-Las Posas.doc CHAPTER 5

DETENTION VAULTS

ANALYSIS

RATIONAL METHOD HYDROGRAPH PROGRAM
COPYRIGHT 1992, 2001 RICK ENGINEERING COMPANY
RUN DATE 2/15/2022
HYDROGRAPH FILE NAME Text1
TIME OF CONCENTRATION 11 MIN.
6 HOUR RAINFALL 3.3 INCHES
BASIN AREA 3.6 ACRES
RUNOFF COEFFICIENT 0.71
PEAK DISCHARGE 13.44 CFS
TIME (MIN) = 0 DISCHARGE (CFS) = 0
TIME (MIN) = 11 DISCHARGE (CFS) = 0.5
TIME (MIN) = 22 DISCHARGE (CFS) = 0.5
TIME (MIN) = 33 DISCHARGE (CFS) = 0.5
TIME (MIN) = 44 DISCHARGE (CFS) = 0.5
TIME (MIN) = 55 DISCHARGE (CFS) = 0.6
TIME (MIN) = 66 DISCHARGE (CFS) = 0.6
TIME (MIN) = 77 DISCHARGE (CFS) = 0.6
TIME (MIN) = 88 DISCHARGE (CFS) = 0.6
TIME (MIN) = 99 DISCHARGE (CFS) = 0.7
TIME (MIN) = 110 DISCHARGE (CFS) = 0.7
TIME (MIN) = 121 DISCHARGE (CFS) = 0.7
TIME (MIN) = 132 DISCHARGE (CFS) = 0.8
TIME (MIN) = 143 DISCHARGE (CFS) = 0.8
TIME (MIN) = 154 DISCHARGE (CFS) = 0.9
TIME (MIN) = 165 DISCHARGE (CFS) = 1
TIME (MIN) = 176 DISCHARGE (CFS) = 1
TIME (MIN) = 187 DISCHARGE (CFS) = 1.2
TIME (MIN) = 198 DISCHARGE (CFS) = 1.3
TIME (MIN) = 209 DISCHARGE (CFS) = 1.6
TIME (MIN) = 220 DISCHARGE (CFS) = 1.8
TIME (MIN) = 231 DISCHARGE (CFS) = 2.6
TIME (MIN) = 242 DISCHARGE (CFS) = 3.7
TIME (MIN) = 253 DISCHARGE (CFS) = 13.44
TIME (MIN) = 264 DISCHARGE (CFS) = 2.1
TIME (MIN) = 275 DISCHARGE (CFS) = 1.4
TIME (MIN) = 286 DISCHARGE (CFS) = 1.1
TIME (MIN) = 297 DISCHARGE (CFS) = 0.9
TIME (MIN) = 308 DISCHARGE (CFS) = 0.8
TIME (MIN) = 319 DISCHARGE (CFS) = 0.7
TIME (MIN) = 330 DISCHARGE (CFS) = 0.7
TIME (MIN) = 341 DISCHARGE (CFS) = 0.6
TIME (MIN) = 352 DISCHARGE (CFS) = 0.6
TIME (MIN) = 363 DISCHARGE (CFS) = 0.5
TIME (MIN) = 374 DISCHARGE (CFS) = 0
RickRatHydro
Inflow Hydrogaph for Vault 2 At Node 108
Time Series 100-YearInflow
Elapsed Time (hours)
111098765
12 10
8 6
4 2
0 LAS PO
SAS - Post-project Condition
SWMM 5.1 Page 1
Inflow Hydrogaph
for Vault 2 At Node 108

RATIONAL METHOD HYDROGRAPH PROGRAM
COPYRIGHT 1992, 2001 RICK ENGINEERING COMPANY
RUN DATE 2/16/2022
HYDROGRAPH FILE NAME Text1
TIME OF CONCENTRATION 9 MIN.
6 HOUR RAINFALL 3.3 INCHES
BASIN AREA 1.9 ACRES
RUNOFF COEFFICIENT 0.71
PEAK DISCHARGE 8.05 CFS
TIME (MIN) = 0 DISCHARGE (CFS) = 0
TIME (MIN) = 9 DISCHARGE (CFS) = 0
TIME (MIN) = 18 DISCHARGE (CFS) = 0.3
TIME (MIN) = 27 DISCHARGE (CFS) = 0.3
TIME (MIN) = 36 DISCHARGE (CFS) = 0.3
TIME (MIN) = 45 DISCHARGE (CFS) = 0.3
TIME (MIN) = 54 DISCHARGE (CFS) = 0.3
TIME (MIN) = 63 DISCHARGE (CFS) = 0.3
TIME (MIN) = 72 DISCHARGE (CFS) = 0.3
TIME (MIN) = 81 DISCHARGE (CFS) = 0.3
TIME (MIN) = 90 DISCHARGE (CFS) = 0.3
TIME (MIN) = 99 DISCHARGE (CFS) = 0.4
TIME (MIN) = 108 DISCHARGE (CFS) = 0.4
TIME (MIN) = 117 DISCHARGE (CFS) = 0.4
TIME (MIN) = 126 DISCHARGE (CFS) = 0.4
TIME (MIN) = 135 DISCHARGE (CFS) = 0.4
TIME (MIN) = 144 DISCHARGE (CFS) = 0.4
TIME (MIN) = 153 DISCHARGE (CFS) = 0.5
TIME (MIN) = 162 DISCHARGE (CFS) = 0.5
TIME (MIN) = 171 DISCHARGE (CFS) = 0.5
TIME (MIN) = 180 DISCHARGE (CFS) = 0.6
TIME (MIN) = 189 DISCHARGE (CFS) = 0.6
TIME (MIN) = 198 DISCHARGE (CFS) = 0.7
TIME (MIN) = 207 DISCHARGE (CFS) = 0.8
TIME (MIN) = 216 DISCHARGE (CFS) = 1
TIME (MIN) = 225 DISCHARGE (CFS) = 1.1
TIME (MIN) = 234 DISCHARGE (CFS) = 1.6
TIME (MIN) = 243 DISCHARGE (CFS) = 2.2
TIME (MIN) = 252 DISCHARGE (CFS) = 8.05
TIME (MIN) = 261 DISCHARGE (CFS) = 1.3
TIME (MIN) = 270 DISCHARGE (CFS) = 0.9
TIME (MIN) = 279 DISCHARGE (CFS) = 0.7
TIME (MIN) = 288 DISCHARGE (CFS) = 0.6
TIME (MIN) = 297 DISCHARGE (CFS) = 0.5
TIME (MIN) = 306 DISCHARGE (CFS) = 0.4
TIME (MIN) = 315 DISCHARGE (CFS) = 0.4
TIME (MIN) = 324 DISCHARGE (CFS) = 0.4
TIME (MIN) = 333 DISCHARGE (CFS) = 0.3
TIME (MIN) = 342 DISCHARGE (CFS) = 0.3
TIME (MIN) = 351 DISCHARGE (CFS) = 0.3
TIME (MIN) = 360 DISCHARGE (CFS) = 0.3
TIME (MIN) = 369 DISCHARGE (CFS) = 0
RickRatHydro
Inflow Hydrogaph for Vault 1 At Node 204
Time Series 100-Year-inflowHydrograph
Elapsed Time (hours)
111098765
8 7
6 5
4 3
2 1
0 LAS PO
SAS - Post-project Condition
SWMM 5.1 Page 1
I
nflow Hydrogaph for Vault 1 At Node 204
HMP-DetentionVault2
HMP-DETENTION-V ault1
Attenuated-flow-Vault2
A ttenuated-flow-vault1
Node108
Node204
08/28/1951 06:00:00
LAS POSAS - Post-project Condition
SWMM 5.1 Page 1
08/28/1951 06:00:00
LAS POSAS - Post-project Condition
SWMM 5.1 Page 1

Vault #1 HMP Discharge
Discharge vs Elevation Table
Low orifice: 4 " Top orifice: 3.000 "
Number: 2 Number: 2.000
Cg-low: 0.61 Cg-low: 0.610
invert elev: 2.50 ft invert elev: 4.500 ft
Middle orifice: 4 " Emergency inlet:
number of orif: 2 Rim height: 5.40 ft
Cg-middle: 0.61 Area 6.00 sq ft <---2' x 3'
invert elev: 3.50 ft Circumference 10.00 ft
h H/D-low H/D-mid H/D-top Qlow-orif Qlow-weir Qtot-low Qmid-orif Qmid-weir Qtot-med Qtop-orif Qtop-weir Qtot-top Qemerg Qtot (ft) - - - (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)

0.0 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.1 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.2 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.3 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.4 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.5 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.6 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.7 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.8 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.9 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.0 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.1 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.2 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.3 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.4 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.5 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.6 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.7 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.8 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.9 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.0 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.1 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.2 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.3 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.4 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.5 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.6 0.30 0.00 0.00 0.000 0.037 0.037 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.037

2.7 0.60 0.00 0.00 0.156 0.138 0.138 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.138

2.8 0.90 0.00 0.00 0.312 0.280 0.280 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.280

2.9 1.20 0.00 0.00 0.413 0.442 0.413 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.413

3.0 1.50 0.00 0.00 0.493 0.600 0.493 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.493

3.10 1.80 0.00 0.00 0.562 0.734 0.562 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.562

3.2 2.10 0.00 0.00 0.624 0.830 0.624 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.624

3.3 2.40 0.00 0.00 0.680 0.883 0.680 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.680

3.4 2.70 0.00 0.00 0.732 0.901 0.732 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.732

3.5 3.00 0.00 0.00 0.780 0.906 0.780 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.780

3.6 3.30 0.30 0.00 0.825 0.938 0.825 0.000 0.037 0.037 0.000 0.000 0.000 0.000 0.863

3.7 3.60 0.60 0.00 0.869 1.061 0.869 0.156 0.138 0.138 0.000 0.000 0.000 0.000 1.006

3.8 3.90 0.90 0.00 0.910 1.358 0.910 0.312 0.280 0.280 0.000 0.000 0.000 0.000 1.18981

3.9 4.20 1.20 0.00 0.949 1.944 0.949 0.413 0.442 0.413 0.000 0.000 0.000 0.000 1.36154

4.0 4.50 1.50 0.00 0.987 2.960 0.987 0.493 0.600 0.493 0.000 0.000 0.000 0.000 1.47983

4.1 4.80 1.80 0.00 1.023 4.584 1.023 0.562 0.734 0.562 0.000 0.000 0.000 0.000 1.585

4.2 5.10 2.10 0.00 1.058 7.028 1.058 0.624 0.830 0.624 0.000 0.000 0.000 0.000 1.682

4.3 5.40 2.40 0.00 1.092 10.542 1.092 0.680 0.883 0.680 0.000 0.000 0.000 0.000 1.772

4.4 5.70 2.70 0.00 1.125 15.420 1.125 0.732 0.901 0.732 0.000 0.000 0.000 0.000 1.8565

4.5 6.00 3.00 0.00 1.157 22.001 1.157 0.780 0.906 0.780 0.000 0.000 0.000 0.000 1.937

4.6 6.30 3.30 0.40 1.188 30.670 1.188 0.825 0.938 0.825 0.000 0.032 0.032 0.000 2.045 0 1
2 0 1 2 3 4 5 6 7 8 9 10
Lower, Middle & Top Orifice
Low Orifice Middle Orifice Top Orifice
01020
30 40
506070
80 90100
0 1 2 3 4 5 6 7 8 91 0
Total Discharge
Combined Total Discharge; Low, Middle, Top Orifice
and Riser

4.7 6.60 3.60 0.80 1.218 41.866 1.218 0.869 1.061 0.869 0.132 0.112 0.112 0.000 2.199

4.8 6.90 3.90 1.20 1.248 56.080 1.248 0.910 1.358 0.910 0.201 0.215 0.201 0.000 2.358

4.9 7.20 4.20 1.60 1.277 73.861 1.277 0.949 1.944 0.949 0.252 0.316 0.252 0.000 2.478

5.0 7.50 4.50 2.00 1.305 95.817 1.305 0.987 2.960 0.987 0.294 0.391 0.294 0.000 2.586

5.1 7.80 4.80 2.40 1.333 122.620 1.333 1.023 4.584 1.023 0.331 0.430 0.331 0.000 2.687

5.2 8.10 5.10 2.80 1.360 155.009 1.360 1.058 7.028 1.058 0.364 0.439 0.364 0.000 2.782

5.3 8.40 5.40 3.20 1.386 193.789 1.386 1.092 10.542 1.092 0.395 0.449 0.395 0.000 2.873

5.4 8.70 5.70 3.60 1.413 239.840 1.413 1.125 15.420 1.125 0.423 0.517 0.423 0.000 2.960

5.5 9.00 6.00 4.00 1.438 294.116 1.438 1.157 22.001 1.157 0.450 0.738 0.450 0.980 4.025

5.6 9.30 6.30 4.40 1.463 357.648 1.463 1.188 30.670 1.188 0.475 1.249 0.475 2.773 5.899

5.7 9.60 6.60 4.80 1.488 431.549 1.488 1.218 41.866 1.218 0.498 2.233 0.498 5.094 8.298

5.8 9.90 6.90 5.20 1.512 517.017 1.512 1.248 56.080 1.248 0.521 3.930 0.521 7.842 11.124

5.9 10.20 7.20 5.60 1.536 615.336 1.536 1.277 73.861 1.277 0.543 6.636 0.543 10.960 14.316

6.0 10.50 7.50 6.00 1.560 727.878 1.560 1.305 95.817 1.305 0.564 10.717 0.564 14.407 17.836 depth area sft area (ac) elevation volume (cf)
volume
(acft)

0.0 2100 0.05 0.0 0 0.00

0.1 2100 0.05 0.1 210 0.00

0.2 2100 0.05 0.2 420 0.01

0.3 2100 0.05 0.3 630 0.01

0.4 2100 0.05 0.4 840 0.02

0.5 2100 0.05 0.5 1050 0.02

0.6 2100 0.05 0.6 1260 0.03

0.7 2100 0.05 0.7 1470 0.03

0.8 2100 0.05 0.8 1680 0.04

0.9 2100 0.05 0.9 1890 0.04

1.0 2100 0.05 1.0 2100 0.05

1.1 2100 0.05 1.1 2310 0.05

1.2 2100 0.05 1.2 2520 0.06

1.3 2100 0.05 1.3 2730 0.06

1.4 2100 0.05 1.4 2940 0.07

1.5 2100 0.05 1.5 3150 0.07

1.6 2100 0.05 1.6 3360 0.08

1.7 2100 0.05 1.7 3570 0.08

1.8 2100 0.05 1.8 3780 0.09

1.9 2100 0.05 1.9 3990 0.09

2.0 2100 0.05 2.0 4200 0.10

2.1 2100 0.05 2.1 4410 0.10

2.2 2100 0.05 2.2 4620 0.11

2.3 2100 0.05 2.3 4830 0.11

2.4 2100 0.05 2.4 5040 0.12

2.5 2100 0.05 2.5 5250 0.12

2.6 2100 0.05 2.6 5460 0.13

2.7 2100 0.05 2.7 5670 0.13

2.8 2100 ` 2.8 5880 0.13

2.9 2100 0.05 2.9 6090 0.14

3.0 2100 0.05 3.0 6300 0.14

3.1 2100 0.05 3.1 6510 0.15

3.2 2100 0.05 3.2 6720 0.15

3.3 2100 0.05 3.3 6930 0.16

3.4 2100 0.05 3.4 7140 0.16

3.5 2100 0.05 3.5 7350 0.17

3.6 2100 0.05 3.6 7560 0.17

3.7 2100 0.05 3.7 7770 0.18

3.8 2100 0.05 3.8 7980 0.18

3.9 2100 0.05 3.9 8190 0.19

4.0 2100 0.05 4.0 8400 0.19

4.1 2100 0.05 4.1 8610 0.20

4.2 2100 0.05 4.2 8820 0.20

4.3 2100 0.05 4.3 9030 0.21

4.4 2100 0.05 4.4 9240 0.21

4.5 2100 0.05 4.5 9450 0.22

4.6 2100 0.05 4.6 9660 0.22

4.7 2100 0.05 4.7 9870 0.23

4.8 2100 0.05 4.8 10080 0.23

4.9 2100 0.05 4.9 10290 0.24

5.0 2100 0.05 5.0 10500 0.24

5.1 2100 0.05 5.1 10710 0.25

5.2 2100 0.05 5.2 10920 0.25

5.3 2100 0.05 5.3 11130 0.26

5.4 2100 0.05 5.4 11340 0.26

5.5 2100 0.05 5.5 11550 0.27

5.6 2100 0.05 5.6 11760 0.27

5.7 2100 0.05 5.7 11970 0.27
Vault#1 Stage Storage
y = 0.0482x
R² =
1 0.00

0.05 0.10

0.15 0.20

0.25 0.30

0.35 0.40

0.45 0.0 5.0 10.0
S
eries1
Li
near
(Series1)
WQ Volume
0 .05

5.8 2100 0.05 5.8 12180 0.28

5.9 2100 0.05 5.9 12390 0.28

6.0 2100 0.05 6.0 12600 0.29

6.1 2100 0.05 6.1 12810 0.29

6.2 2100 0.05 6.2 13020 0.30

6.3 2100 0.05 6.3 13230 0.30

6.4 2100 0.05 6.4 13440 0.31

6.5 2100 0.05 6.5 13650 0.31
Discharge vs Elevation Table
Low orifice: 1.6 " Top orifice: 8 "
Number: 1 Number: 0
Cg-low: 0.61 Cg-low: 0.61
invert elev: 0.00 ft invert elev: 0.00 ft
Middle orifice: 1.5 " Emergency inlet:
number of orif: 0 Rim height: 4.75 ft
Cg-middle: 0.61 Area 6.00 sq ft <--- 3' x2'
invert elev: 0.50 ft Circumference 10.00 ft
h H/D-low H/D-mid H/D-top Qlow-orif Qlow-weir Qtot-low Qmid-orif Qmid-weir Qtot-med Qtop-orif Qtop-weir Qtot-top Qemerg Qtot (ft) - - - (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)

0.0 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.1 0.75 0.00 0.15 0.012 0.010 0.010 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.010

0.2 1.50 0.00 0.30 0.025 0.030 0.025 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.025

0.3 2.25 0.00 0.45 0.033 0.044 0.033 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.033

0.4 3.00 0.00 0.60 0.039 0.046 0.039 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.039

0.5 3.75 0.00 0.75 0.045 0.060 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.045

0.6 4.50 0.80 0.90 0.050 0.150 0.050 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.050

0.7 5.25 1.60 1.05 0.054 0.437 0.054 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.054

0.8 6.00 2.40 1.20 0.059 1.113 0.059 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.059

0.9 6.75 3.20 1.35 0.062 2.457 0.062 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.062

1.0 7.50 4.00 1.50 0.066 4.848 0.066 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.066

1.1 8.25 4.80 1.65 0.069 8.781 0.069 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.069

1.2 9.00 5.60 1.80 0.073 14.881 0.073 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.073

1.3 9.75 6.40 1.95 0.076 23.920 0.076 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.076

1.4 10.50 7.20 2.10 0.079 36.828 0.079 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.079

1.5 11.25 8.00 2.25 0.082 54.712 0.082 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.082

1.6 12.00 8.80 2.40 0.085 78.866 0.085 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.085

1.7 12.75 9.60 2.55 0.087 110.792 0.087 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.087

1.8 13.50 10.40 2.70 0.090 152.208 0.090 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.090

1.9 14.25 11.20 2.85 0.093 205.069 0.093 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.093

2.0 15.00 12.00 3.00 0.095 271.576 0.095 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.095

2.1 15.75 12.80 3.15 0.097 354.197 0.097 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.097

2.2 16.50 13.60 3.30 0.100 455.676 0.100 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.100

2.3 17.25 14.40 3.45 0.102 579.052 0.102 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.102

2.4 18.00 15.20 3.60 0.104 727.670 0.104 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.104

2.5 18.75 16.00 3.75 0.107 905.200 0.107 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.107 Vault #1 WQ Discharge to the
MWS BF-3-1 (was not included
in detention calcs)
Elevation QAVG (CFS) DV (CF) DT (HR) Total T

0.1 0.01 210 11.25 37.12

0.2 0.02 210 3.30 25.87

0.3 0.03 210 2.01 22.57

0.4 0.04 210 1.61 20.56

0.5 0.04 210 1.38 18.95

0.6 0.05 210 1.23 17.57

0.7 0.05 210 1.12 16.34

0.8 0.06 210 1.03 15.22

0.9 0.06 210 0.96 14.19

1.0 0.06 210 0.91 13.22

1.1 0.07 210 0.86 12.31

1.2 0.07 210 0.82 11.45

1.3 0.07 210 0.78 10.63

1.4 0.08 210 0.75 9.85

1.5 0.08 210 0.73 9.09

1.6 0.08 210 0.70 8.37

1.7 0.09 210 0.68 7.67

1.8 0.09 210 0.66 6.99

1.9 0.09 210 0.64 6.33

2.0 0.09 210 0.62 5.69

2.1 0.10 210 0.61 5.07

2.2 0.10 210 0.59 4.46

2.3 0.10 210 0.58 3.87

2.4 0.10 210 0.56 3.30

2.5 0.11 210 0.55 2.73

2.6 0.13 210 0.46 2.18

2.7 0.20 210 0.30 1.72

2.8 0.32 210 0.18 1.42

2.9 0.46 210 0.13 1.24

3.0 0.57 210 0.10 1.11

3.1 0.65 210 0.09 1.01

3.2 0.71 210 0.08 0.92

3.3 0.77 210 0.08 0.84

3.4 0.83 210 0.07 0.76

3.5 0.88 210 0.07 0.69

3.6 0.95 210 0.06 0.63

3.7 1.06 210 0.05 0.56

3.8 1.23 210 0.05 0.51

3.9 1.41 210 0.04 0.46

4.0 1.56 210 0.04 0.42

4.1 1.67 210 0.03 0.38

4.2 1.77 210 0.03 0.35

4.3 1.87 210 0.03 0.32

4.4 1.96 210 0.03 0.28
Total Vault Draw Down
WQ Volume

4.5 2.04 210 0.03 0.25

4.6 2.14 210 0.03 0.23

4.7 2.27 210 0.03 0.20

4.8 2.43 210 0.02 0.17

4.9 2.57 210 0.02 0.15

5.0 2.68 210 0.02 0.13

5.1 2.79 210 0.02 0.10

5.2 2.89 210 0.02 0.08

5.3 3.47 210 0.02 0.06

5.4 4.95 210 0.01 0.05

5.5 7.58 210 0.01 0.03

5.6 11.59 210 0.01 0.03

5.7 16.66 210 0.00 0.02

5.8 22.56 210 0.00 0.02

5.9 29.17 210 0.00 0.02

6.0 25.24 210 0.00 0.01

6.1 19.75 210 0.00 0.01

6.2 23.70 210 0.00 0.01

6.3 27.93 210 0.00 0.01

6.4 31.59 210 0.00 0.00

6.5 33.82 210 0.00 0.00
08/28/1951 06:00:00
LAS POSAS - Post-project Condition
SWMM 5.1 Page 1

Vault #2 HMP Discharge
Discharge vs Elevation Table
Low orifice: 2 " Top orifice: 3 "
Number: 1 Number: 10
Cg-low: 0.61 Cg-low: 0.61
invert elev: 2.60 ft invert elev: 5.00 ft
Middle orifice: 3 " Emergency inlet:
number of orif: 10 Rim height: 5.90 ft
Cg-middle: 0.61 Area 12.00 sq ft <---4' x 3'
invert elev: 3.40 ft Circumference 14.00 ft
h H/D-low H/D-mid H/D-top Qlow-orif Qlow-weir Qtot-low Qmid-orif Qmid-weir Qtot-med Qtop-orif Qtop-weir Qtot-top Qemerg Qtot (ft) - - - (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)

0.0 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.1 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.2 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.3 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.4 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.5 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.6 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.7 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.8 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.9 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.0 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.1 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.2 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.3 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.4 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.5 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.6 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.7 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.8 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.9 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.0 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.1 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.2 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.3 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.4 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.5 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.6 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.7 0.60 0.00 0.00 0.014 0.012 0.012 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.012

2.8 1.20 0.00 0.00 0.036 0.039 0.036 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.036

2.9 1.80 0.00 0.00 0.050 0.065 0.050 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.050

3.0 2.40 0.00 0.00 0.060 0.078 0.060 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.060

3.1 3.00 0.00 0.00 0.069 0.080 0.069 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.069

3.2 3.60 0.00 0.00 0.077 0.094 0.077 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.077

3.3 4.20 0.00 0.00 0.084 0.172 0.084 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.084

3.4 4.80 0.00 0.00 0.090 0.405 0.090 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.090

3.5 5.40 0.40 0.00 0.097 0.932 0.097 0.000 0.158 0.158 0.000 0.000 0.000 0.000 0.254

3.6 6.00 0.80 0.00 0.102 1.945 0.102 0.658 0.559 0.559 0.000 0.000 0.000 0.000 0.661

3.7 6.60 1.20 0.00 0.108 3.700 0.108 1.005 1.077 1.005 0.000 0.000 0.000 0.000 1.113

3.8 7.20 1.60 0.00 0.113 6.528 0.113 1.260 1.578 1.260 0.000 0.000 0.000 0.000 1.373

3.9 7.80 2.00 0.00 0.118 10.838 0.118 1.471 1.954 1.471 0.000 0.000 0.000 0.000 1.589

4.0 8.40 2.40 0.00 0.123 17.129 0.123 1.656 2.150 1.656 0.000 0.000 0.000 0.000 1.779

4.1 9.00 2.80 0.00 0.127 25.996 0.127 1.822 2.197 1.822 0.000 0.000 0.000 0.000 1.949 0 1
2 0 1 2 3 4 5 6 7 8 9 10
Low
er, Middle & Top Orifice
L
ow Orifice M
iddle Orifice Top
Orifice
010203040506070809010
0 0 1 2 3 4 5 6 7 8 9 10
Total Discharge
Co
mbined Total Discharge; Low, Middle, Top Orifice
and Riser

4.2 9.60 3.20 0.00 0.132 38.144 0.132 1.974 2.243 1.974 0.000 0.000 0.000 0.000 2.106

4.3 10.20 3.60 0.00 0.136 54.389 0.136 2.115 2.583 2.115 0.000 0.000 0.000 0.000 2.251

4.4 10.80 4.00 0.00 0.140 75.670 0.140 2.248 3.690 2.248 0.000 0.000 0.000 0.000 2.388

4.5 11.40 4.40 0.00 0.144 103.061 0.144 2.373 6.244 2.373 0.000 0.000 0.000 0.000 2.517

4.6 12.00 4.80 0.00 0.148 137.773 0.148 2.491 11.166 2.491 0.000 0.000 0.000 0.000 2.639

4.7 12.60 5.20 0.00 0.152 181.166 0.152 2.605 19.648 2.605 0.000 0.000 0.000 0.000 2.756

4.8 13.20 5.60 0.00 0.155 234.757 0.155 2.713 33.180 2.713 0.000 0.000 0.000 0.000 2.869

4.9 13.80 6.00 0.00 0.159 300.229 0.159 2.818 53.587 2.818 0.000 0.000 0.000 0.000 2.977

5.0 14.40 6.40 0.00 0.163 379.439 0.163 2.918 83.053 2.918 0.000 0.000 0.000 0.000 3.081

5.1 15.00 6.80 0.40 0.166 474.424 0.166 3.016 124.157 3.016 0.000 0.158 0.158 0.000 3.339

5.2 15.60 7.20 0.80 0.169 587.416 0.169 3.110 179.902 3.110 0.658 0.559 0.559 0.000 3.838

5.3 16.20 7.60 1.20 0.173 720.842 0.173 3.201 253.745 3.201 1.005 1.077 1.005 0.000 4.379

5.4 16.80 8.00 1.60 0.176 877.340 0.176 3.290 349.629 3.290 1.260 1.578 1.260 0.000 4.726

5.5 17.40 8.40 2.00 0.179 1059.762 0.179 3.377 472.011 3.377 1.471 1.954 1.471 0.000 5.028

5.6 18.00 8.80 2.40 0.182 1271.187 0.182 3.461 625.898 3.461 1.656 2.150 1.656 0.000 5.300

5.7 18.60 9.20 2.80 0.185 1514.925 0.185 3.544 816.871 3.544 1.822 2.197 1.822 0.000 5.551

5.8 19.20 9.60 3.20 0.189 1794.529 0.189 3.624 1051.123 3.624 1.974 2.243 1.974 0.000 5.787

5.9 19.80 10.00 3.60 0.192 2113.801 0.192 3.703 1335.483 3.703 2.115 2.583 2.115 0.000 6.010

6.0 20.40 10.40 4.00 0.194 2476.804 0.194 3.780 1677.452 3.780 2.248 3.690 2.248 1.372 7.595 depth area sft area (ac) elevation volume (cf)
volume
(acft)

0.0 3500 0.08 0.0 0 0.00

0.1 3500 0.08 0.1 350 0.01

0.2 3500 0.08 0.2 700 0.02

0.3 3500 0.08 0.3 1050 0.02

0.4 3500 0.08 0.4 1400 0.03

0.5 3500 0.08 0.5 1750 0.04

0.6 3500 0.08 0.6 2100 0.05

0.7 3500 0.08 0.7 2450 0.06

0.8 3500 0.08 0.8 2800 0.06

0.9 3500 0.08 0.9 3150 0.07

1.0 3500 0.08 1.0 3500 0.08

1.1 3500 0.08 1.1 3850 0.09

1.2 3500 0.08 1.2 4200 0.10

1.3 3500 0.08 1.3 4550 0.10

1.4 3500 0.08 1.4 4900 0.11

1.5 3500 0.08 1.5 5250 0.12

1.6 3500 0.08 1.6 5600 0.13

1.7 3500 0.08 1.7 5950 0.14

1.8 3500 0.08 1.8 6300 0.14

1.9 3500 0.08 1.9 6650 0.15

2.0 3500 0.08 2.0 7000 0.16

2.1 3500 0.08 2.1 7350 0.17

2.2 3500 0.08 2.2 7700 0.18

2.3 3500 0.08 2.3 8050 0.18

2.4 3500 0.08 2.4 8400 0.19

2.5 3500 0.08 2.5 8750 0.20

2.6 3500 0.08 2.6 9100 0.21

2.7 3500 0.08 2.7 9450 0.22

2.8 3500 0.08 2.8 9800 0.22

2.9 3500 0.08 2.9 10150 0.23

3.0 3500 0.08 3.0 10500 0.24

3.1 3500 0.08 3.1 10850 0.25

3.2 3500 0.08 3.2 11200 0.26

3.3 3500 0.08 3.3 11550 0.27

3.4 3500 0.08 3.4 11900 0.27

3.5 3500 0.08 3.5 12250 0.28

3.6 3500 0.08 3.6 12600 0.29

3.7 3500 0.08 3.7 12950 0.30

3.8 3500 0.08 3.8 13300 0.31

3.9 3500 0.08 3.9 13650 0.31

4.0 3500 0.08 4.0 14000 0.32

4.1 3500 0.08 4.1 14350 0.33

4.2 3500 0.08 4.2 14700 0.34

4.3 3500 0.08 4.3 15050 0.35

4.4 3500 0.08 4.4 15400 0.35

4.5 3500 0.08 4.5 15750 0.36

4.6 3500 0.08 4.6 16100 0.37

4.7 3500 0.08 4.7 16450 0.38

4.8 3500 0.08 4.8 16800 0.39

4.9 3500 0.08 4.9 17150 0.39

5.0 3500 0.08 5.0 17500 0.40

5.1 3500 0.08 5.1 17850 0.41

5.2 3500 0.08 5.2 18200 0.42

5.3 3500 0.08 5.3 18550 0.43

5.4 3500 0.08 5.4 18900 0.43

5.5 3500 0.08 5.5 19250 0.44

5.6 3500 0.08 5.6 19600 0.45

5.7 3500 0.08 5.7 19950 0.46
Vault#2 Stage Storage
y = 0.0803x
R²
= 1

0.00 0.10

0.20 0.30

0.40 0.50

0.60 0.70

0.0 5.0 10.0
S
eries1
Li
near
(Series1)
WQ Volume

5.8 3500 0.08 5.8 20300 0.47

5.9 3500 0.08 5.9 20650 0.47

6.0 3500 0.08 6.0 21000 0.48

6.1 3500 0.08 6.1 21350 0.49

6.2 3500 0.08 6.2 21700 0.50

6.3 3500 0.08 6.3 22050 0.51

6.4 3500 0.08 6.4 22400 0.51

6.5 3500 0.08 6.5 22750 0.52
Vault #2 WQ Discharge
Discharge vs Elevation Table
Low orifice: 2.3 " Top orifice: 8 "
Number: 1 Number: 0
Cg-low: 0.61 Cg-low: 0.61
invert elev: 0.00 ft invert elev: 0.00 ft
Middle orifice: 3 " Emergency inlet:
number of orif: 0 Rim height: 5.00 ft
Cg-middle: 0.61 Area 25.00 sq ft <--- 5' x 5'
invert elev: 3.20 ft Circumference 20.00 ft
h H/D-low H/D-mid H/D-top Qlow-orif Qlow-weir Qtot-low Qmid-orif Qmid-weir Qtot-med Qtop-orif Qtop-weir Qtot-top Qemerg Qtot (ft) - - - (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)

0.0 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.1 0.52 0.00 0.15 0.009 0.013 0.013 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.013

0.2 1.04 0.00 0.30 0.046 0.045 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.045

0.3 1.57 0.00 0.45 0.064 0.079 0.064 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.064

0.4 2.09 0.00 0.60 0.078 0.104 0.078 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.078

0.5 2.61 0.00 0.75 0.090 0.113 0.090 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.090

0.6 3.13 0.00 0.90 0.100 0.114 0.100 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.100

0.7 3.65 0.00 1.05 0.110 0.138 0.110 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.110

0.8 4.17 0.00 1.20 0.119 0.235 0.119 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.119

0.9 4.70 0.00 1.35 0.127 0.494 0.127 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.127

1.0 5.22 0.00 1.50 0.134 1.035 0.134 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.134

1.1 5.74 0.00 1.65 0.142 2.027 0.142 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.142

1.2 6.26 0.00 1.80 0.148 3.686 0.148 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.148

1.3 6.78 0.00 1.95 0.155 6.283 0.155 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.155

1.4 7.30 0.00 2.10 0.161 10.153 0.161 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.161

1.5 7.83 0.00 2.25 0.167 15.695 0.167 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.167

1.6 8.35 0.00 2.40 0.173 23.385 0.173 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.173

1.7 8.87 0.00 2.55 0.179 33.776 0.179 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.179

1.8 9.39 0.00 2.70 0.184 47.508 0.184 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.184

1.9 9.91 0.00 2.85 0.190 65.312 0.190 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.190

2.0 10.43 0.00 3.00 0.195 88.015 0.195 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.195

2.1 10.96 0.00 3.15 0.200 116.550 0.200 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.200

2.2 11.48 0.00 3.30 0.205 151.957 0.205 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.205

2.3 12.00 0.00 3.45 0.210 195.393 0.210 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.210

2.4 12.52 0.00 3.60 0.214 248.135 0.214 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.214

2.5 13.04 0.00 3.75 0.219 311.587 0.219 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.219 Vault #2 WQ Discharge to the
MWS BF-3-2 (was not included
in detention calcs)
Elevation QAVG (CFS) DV (CF) DT (HR) Total T

0.1 0.01 350 14.58 39.00

0.2 0.03 350 3.35 24.43

0.3 0.05 350 1.79 21.08

0.4 0.07 350 1.37 19.29

0.5 0.08 350 1.16 17.92

0.6 0.10 350 1.02 16.76

0.7 0.11 350 0.93 15.73

0.8 0.11 350 0.85 14.81

0.9 0.12 350 0.79 13.96

1.0 0.13 350 0.75 13.16

1.1 0.14 350 0.70 12.42

1.2 0.14 350 0.67 11.71

1.3 0.15 350 0.64 11.04

1.4 0.16 350 0.61 10.40

1.5 0.16 350 0.59 9.79

1.6 0.17 350 0.57 9.19

1.7 0.18 350 0.55 8.62

1.8 0.18 350 0.54 8.07

1.9 0.19 350 0.52 7.54

2.0 0.19 350 0.51 7.02

2.1 0.20 350 0.49 6.51

2.2 0.20 350 0.48 6.02

2.3 0.21 350 0.47 5.54

2.4 0.21 350 0.46 5.07

2.5 0.22 350 0.45 4.61

2.6 0.22 350 0.44 4.16

2.7 0.23 350 0.42 3.72

2.8 0.25 350 0.38 3.30

2.9 0.28 350 0.35 2.92

3.0 0.29 350 0.33 2.57

3.1 0.31 350 0.32 2.24

3.2 0.32 350 0.30 1.92

3.3 0.33 350 0.29 1.62

3.4 0.34 350 0.28 1.33

3.5 0.43 350 0.23 1.04

3.6 0.72 350 0.14 0.82

3.7 1.15 350 0.08 0.68

3.8 1.51 350 0.06 0.60

3.9 1.75 350 0.06 0.53

4.0 1.96 350 0.05 0.48

4.1 2.14 350 0.05 0.43

4.2 2.31 350 0.04 0.38

4.3 2.47 350 0.04 0.34

4.4 2.61 350 0.04 0.30
Total Vault Draw Down
WQ Volume

4.5 2.75 350 0.04 0.26

4.6 2.88 350 0.03 0.23

4.7 3.00 350 0.03 0.19

4.8 3.12 350 0.03 0.16

4.9 3.23 350 0.03 0.13

5.0 3.34 350 0.03 0.10

5.1 4.50 350 0.02 0.07

5.2 7.66 350 0.01 0.05

5.3 12.30 350 0.01 0.04

5.4 17.81 350 0.01 0.03

5.5 24.01 350 0.00 0.02

5.6 30.86 350 0.00 0.02

5.7 38.32 350 0.00 0.02

5.8 46.34 350 0.00 0.01

5.9 54.89 350 0.00 0.01

6.0 63.93 350 0.00 0.01

6.1 73.92 350 0.00 0.01

6.2 85.26 350 0.00 0.01

6.3 97.70 350 0.00 0.01

6.4 111.02 350 0.00 0.00

6.5 125.14 350 0.00 0.00

6.6 139.99 350 0.00 0.00

6.7 155.52 350 0.00 0.00

6.8 171.70 350 0.00 0.00

6.9 188.50 350 0.00 0.00

7.0 203.93 350 0.00 0.00
Node Inflow Summary
Maximum Maximum Lateral Total Flow
Lateral Total Day of Hour of Inflow Inflow Balance
Inflow Inflow Maximum Maximum V olume V olume Error
Node Type CFS CFS Inflow Inflow 10^6 gal 10^6 gal Percent Attenuated-flow
-Vault2 OUTFALL 0.00 5.85 0 04:22 0 0.227 0.000
Attenuated-flow-
vault1 OUTFALL 0.00 2.79 0 04:20 0 0.12 0.000
Node108 STORAGE 13.44 13.44 0 04:14 0.227 0.295 0.006
Node204 STORAGE 8.05 8.05 0 04:13 0.12 0.159 0.006
LAS POSAS - Post-project Condition
SWMM 5.1 Page 1
Node Depth Summary
Maximum
Average Maximum Maximum Day of Hour of Reported
Depth Depth HGL Maximum Maximum Depth
Node Type Feet Feet Feet Depth Depth Feet
Node108 STORAGE 2.60 5.83 5.83 0 04:22 4.43
Node204 STORAGE 2.50 5.21 5.21 0 04:20 3.87
LAS POSAS - Post-project Condition
SWMM 5.1 Page 1
CHAPTER 6

HYDRAULIC ANALYSIS TO

CHECK THE CAPACITY OF THE
PROPOSED 24" PIPE AT THE

DISCHARGE LOCATION
(TO NODE 1)

HEC-RAS ANALYSIS FOR LAS

POSAS CREEK AT THE

CROSS SECTION AT TH

GRADING AREA
CHAPTER 6 - 1

HYDRAULIC ANALYSIS TO

CHECK THE CAPACITY OF THE
PROPOSED 24" PIPE AT THE

DISCHARGE LOCATION
(TO NODE 1)
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Aug 25 2021 Proposed Storm Drain at the discharge location to the Headwall Circular
Diameter (ft) = 2.00
Invert Elev (ft) = 564.50
Slope (%) = 0.83
N-Value = 0.013
Calculations
Compute by: Known Q
Known Q (cfs) = 11.18
Highlighted
Depth (ft) = 1.05
Q (cfs) = 11.18
Area (sqft) = 1.68
Velocity (ft/s) = 6.66
Wetted Perim (ft) = 3.25
Crit Depth, Yc (ft) = 1.20
Top Width (ft) = 2.00
EGL (ft) = 1.74
0 1 2 3 4
Elev (ft) Depth (ft) Section
564.00 -0.50
564.50 0.00
565.00 0.50
565.50 1.00
566.00 1.50
566.50 2.00
567.00 2.50
Reach (ft)

CHAPTER 6 -2

HEC-RAS ANALYSIS FOR LAS

POSAS CREEK AT THE

CROSS SECTION AT TH

GRADING AREA
HEC-RAS Plan: Plan 08 River: Las Posas Reach: Desc. - SR 78 Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Desc. - SR 78 1300 Base 1417.00 564.30 569.37 570.65 0.006269 9.06 156.39 42.25 0.83 Desc. - SR 78 1300 Floodway 1417.00 564.30 569.73 569.67 572.38 0.012995 13.06 108.51 20.00 0.99 Desc. - SR 78 1200 Base 1417.00 560.00 565.46 564.74 566.73 0.005806 9.04 156.80 158.32 0.78 Desc. - SR 78 1200 Floodway 1417.00 560.00 565.60 564.72 566.80 0.005318 8.79 161.15 36.86 0.74 Desc. - SR 78 1100 Base 1417.00 554.50 565.60 559.29 565.93 0.001112 4.64 305.19 457.94 0.25 Desc. - SR 78 1100 Floodway 1417.00 554.50 565.64 559.31 565.97 0.001344 4.63 305.92 30.00 0.25 Desc. - SR 78 1050 Culvert
Desc. - SR 78 1000 Base 1417.00 554.08 557.85 557.85 559.70 0.002128 10.93 129.62 165.23 1.00 Desc. - SR 78 1000 Floodway 1417.00 554.08 557.90 557.90 559.80 0.002724 11.06 128.18 34.00 1.00 Desc. - SR 78 900 Base 1417.00 554.00 556.78 556.78 557.96 0.002713 8.71 162.64 70.00 1.01 Desc. - SR 78 900 Floodway 1417.00 554.00 556.78 556.78 557.96 0.002711 8.71 162.67 70.00 1.01 Desc. - SR 78 855 Base 1417.00 550.85 555.17 555.17 556.61 0.002663 9.60 147.63 52.45 1.01 Desc. - SR 78 855 Floodway 1417.00 550.85 555.17 555.17 556.61 0.002664 9.60 147.61 52.45 1.01 Desc. - SR 78 800 Base 1417.00 550.70 554.82 553.75 555.55 0.000874 6.84 207.04 316.55 0.62 Desc. - SR 78 800 Floodway 1417.00 550.70 554.83 553.77 555.55 0.000952 6.84 207.12 54.00 0.62 Desc. - SR 78 793 Base 1417.00 550.40 554.49 553.88 555.52 0.001378 8.14 174.15 208.10 0.76 Desc. - SR 78 793 Floodway 1417.00 550.40 554.49 553.88 555.52 0.001499 8.13 174.19 49.00 0.76 Desc. - SR 78 780 Base 917.00 550.95 554.25 554.25 555.48 0.002278 8.92 105.08 274.00 0.94 Desc. - SR 78 780 Floodway 917.00 550.95 554.25 554.25 555.48 0.002512 8.89 105.39 48.10 0.94 Desc. - SR 78 775 Base 917.00 550.00 553.17 553.17 554.26 0.002591 8.35 109.83 67.33 1.00 Desc. - SR 78 775 Floodway 917.00 550.00 553.17 553.17 554.26 0.002723 8.35 109.83 50.41 1.00 Desc. - SR 78 725 Base 917.00 549.00 550.29 550.29 550.55 0.003745 4.04 227.00 417.31 0.97 Desc. - SR 78 725 Floodway 917.00 549.00 551.11 551.69 0.001766 6.14 149.26 80.00 0.79 Desc. - SR 78 700 Base 917.00 548.00 549.66 549.73 0.000442 2.07 442.99 446.97 0.37 Desc. - SR 78 700 Floodway 917.00 548.53 550.58 550.58 551.50 0.002876 7.68 119.39 65.00 1.00 Desc. - SR 78 600 Base 917.00 544.00 549.70 549.71 0.000002 0.42 2850.09 1019.55 0.03 Desc. - SR 78 600 Floodway 917.00 544.00 549.70 549.71 0.000006 0.69 1345.32 275.00 0.05 Desc. - SR 78 500 Base 917.00 541.20 549.14 545.22 549.65 0.000213 5.75 159.51 1009.25 0.36 Desc. - SR 78 500 Floodway 917.00 541.20 549.14 545.22 549.65 0.000462 5.75 159.51 20.09 0.36 Desc. - SR 78 450 Culvert
Desc. - SR 78 400 Base 917.00 537.40 541.45 541.45 543.47 0.002063 11.42 80.27 401.95 1.00 Desc. - SR 78 400 Floodway 917.00 537.40 541.45 541.45 543.47 0.002063 11.42 80.27 345.00 1.00 Desc. - SR 78 300 Base 917.00 538.00 540.03 540.11 0.000446 2.22 414.11 390.66 0.37 Desc. - SR 78 300 Floodway 917.00 538.00 540.80 540.80 542.17 0.002796 9.41 97.42 35.00 0.99 Desc. - SR 78 200 Base 1109.00 536.00 539.37 539.37 539.88 0.001426 6.77 237.35 232.50 0.76 Desc. - SR 78 200 Floodway 1109.00 536.00 539.38 539.38 539.87 0.001360 6.63 239.71 224.03 0.75 Existing Conditions
0 200 400 600 800 1000
560
565
570
575
580
La
s Posas LOMR Plan: Post-Project Conditions Floodway 2/18/2022 Station (ft)
Elevation (ft)
Legend
EG Flo
odway
EG Ba
se
W
S Floodway
W
S Base
Cr
it Base
Crit
Floodway
G
round
I
neff
Ba
nk Sta
Enc
roachment
.03 .03 .03
0 200 400 600 800 1000 1200 1400
554
556
558
560
562
564
566
568
570
Las Posas LOMR Plan: Post-Project Conditions Floodway 2/18/2022 Station (ft)
Elevation (ft)
Legend
EG Flo
odway
EG Ba
se
W
S Floodway
W
S Base
Crit
Floodway
Cr
it Base
G
round
I
neff
Ba
nk Sta
Enc
roachment
.045 .045 .045
HEC-RAS Plan: P10 River: Las Posas Reach: Desc. - SR 78 Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Desc. - SR 78 1300 Base 1417.00 564.30 569.37 570.65 0.006269 9.06 156.39 42.25 0.83 Desc. - SR 78 1300 Floodway 1417.00 564.30 569.73 569.67 572.38 0.012995 13.06 108.51 20.00 0.99 Desc. - SR 78 1200 Base 1417.00 560.00 565.46 564.74 566.73 0.005806 9.04 156.80 158.32 0.78 Desc. - SR 78 1200 Floodway 1417.00 560.00 565.60 564.72 566.80 0.005318 8.79 161.15 36.86 0.74 Desc. - SR 78 1100 Base 1417.00 554.50 565.60 559.29 565.93 0.001112 4.64 305.19 457.94 0.25 Desc. - SR 78 1100 Floodway 1417.00 554.50 565.64 559.31 565.97 0.001344 4.63 305.92 30.00 0.25 Desc. - SR 78 1050 Culvert
Desc. - SR 78 1000 Base 1417.00 554.08 557.85 557.85 559.70 0.002128 10.93 129.62 165.23 1.00 Desc. - SR 78 1000 Floodway 1417.00 554.08 557.90 557.90 559.80 0.002724 11.06 128.18 34.00 1.00 Desc. - SR 78 900 Base 1417.00 554.00 556.78 556.78 557.96 0.002713 8.71 162.64 70.00 1.01 Desc. - SR 78 900 Floodway 1417.00 554.00 556.78 556.78 557.96 0.002711 8.71 162.67 70.00 1.01 Desc. - SR 78 855 Base 1417.00 550.85 555.17 555.17 556.61 0.002663 9.60 147.63 52.45 1.01 Desc. - SR 78 855 Floodway 1417.00 550.85 555.17 555.17 556.61 0.002664 9.60 147.61 52.45 1.01 Desc. - SR 78 800 Base 1417.00 550.70 554.82 553.75 555.55 0.000874 6.84 207.04 316.55 0.62 Desc. - SR 78 800 Floodway 1417.00 550.70 554.83 553.77 555.55 0.000952 6.84 207.12 54.00 0.62 Desc. - SR 78 793 Base 1417.00 550.40 554.49 553.88 555.52 0.001378 8.14 174.15 208.10 0.76 Desc. - SR 78 793 Floodway 1417.00 550.40 554.49 553.88 555.52 0.001499 8.13 174.19 49.00 0.76 Desc. - SR 78 780 Base 917.00 550.95 554.25 554.25 555.48 0.002278 8.92 105.08 274.00 0.94 Desc. - SR 78 780 Floodway 917.00 550.95 554.25 554.25 555.48 0.002512 8.89 105.39 48.10 0.94 Desc. - SR 78 775 Base 917.00 550.00 553.17 553.17 554.26 0.002591 8.35 109.83 67.33 1.00 Desc. - SR 78 775 Floodway 917.00 550.00 553.17 553.17 554.26 0.002723 8.35 109.83 50.41 1.00 Desc. - SR 78 725 Base 917.00 549.00 550.29 550.29 550.55 0.003745 4.04 227.00 417.31 0.97 Desc. - SR 78 725 Floodway 917.00 549.00 551.11 551.69 0.001766 6.14 149.26 80.00 0.79 Desc. - SR 78 700 Base 917.00 548.00 549.66 549.73 0.000442 2.07 442.99 446.97 0.37 Desc. - SR 78 700 Floodway 917.00 548.53 550.58 550.58 551.50 0.002876 7.68 119.39 65.00 1.00 Desc. - SR 78 600 Base 917.00 544.00 549.70 549.71 0.000002 0.42 2850.09 1019.55 0.03 Desc. - SR 78 600 Floodway 917.00 544.00 549.70 549.71 0.000006 0.69 1345.32 275.00 0.05 Desc. - SR 78 500 Base 917.00 541.20 549.14 545.22 549.65 0.000213 5.75 159.51 1009.25 0.36 Desc. - SR 78 500 Floodway 917.00 541.20 549.14 545.22 549.65 0.000462 5.75 159.51 20.09 0.36 Desc. - SR 78 450 Culvert
Desc. - SR 78 400 Base 917.00 537.40 541.45 541.45 543.47 0.002063 11.42 80.27 401.95 1.00 Desc. - SR 78 400 Floodway 917.00 537.40 541.45 541.45 543.47 0.002063 11.42 80.27 345.00 1.00 Desc. - SR 78 300 Base 917.00 538.00 540.03 540.11 0.000446 2.22 414.11 390.66 0.37 Desc. - SR 78 300 Floodway 917.00 538.00 540.80 540.80 542.17 0.002796 9.41 97.42 35.00 0.99 Desc. - SR 78 200 Base 1109.00 536.00 539.37 539.37 539.88 0.001426 6.77 237.35 232.50 0.76 Desc. - SR 78 200 Floodway 1109.00 536.00 539.38 539.38 539.87 0.001360 6.63 239.71 224.03 0.75 proposed Conditions
0 200 400 600 800 1000
560
565
570
575
580
La
s Posas LOMR Plan: Plan 02 2/18/2022
Station (ft)
Elevation (ft)
Legend
EG Flo
odway
EG Ba
se
W
S Floodway
W
S Base
Cr
it Base
Crit
Floodway
G
round
I
neff
Ba
nk Sta
Enc
roachment
.03 .03 .03
0 200 400 600 800 1000 1200 1400
554
556
558
560
562
564
566
568
570
Las Posas LOMR Plan: Plan 02 2/18/2022
Station (ft)
Elevation (ft)
Legend
EG Flo
odway
EG Ba
se
W
S Floodway
W
S Base
Crit
Floodway
Cr
it Base
G
round
I
neff
Ba
nk Sta
Enc
roachment
.045 .045 .045
Drainage Study for Discovery Village
RE:jk R:\1482\&Hyd\Hydrology\Report\1482- DR-Las Posas.doc w.o. 0061-0499
CHAPTER 7

HYDROLOGY MAPS

Chapter 7

FEMA MAP

Project Location

Drainage Study for Discovery Village
RE:jk R:\1482\&Hyd\Hydrology\Report\1482- DR-Las Posas.doc w.o. 0061-0499
Chapter 9

REFERNCE REPORT AND MAP

HYDROLOGY& HYDRAULIC STUDY FOR

CVS PHARMACY

NORTH LAS POSAS AND WEST MISSION ROAD,

SAN MARCOS, CA

ENGINEER OF WORK

EXCEL ENGINEERING
440 State Place
Escondido, CA 92029
(760) 745-8118
Project No. 05-036
December 19, 2008
Revision 1: January 13, 2009
Revision 2: February 9, 2009

HYDROLOGY STUDY FOR

CVS PHARMACY, LAS POSAS AND MISSION ROAD
4 6.3 Runoff Calculation using Rational Method
Runoff coefficient is obtained using Table 3-1 of San Diego County Hydrology Manual 2003, C= 0.35 is used for the undeveloped area and C= 0.79 for soil type D and commercial/Industrial area.

Figure A. Flow scheme for Pre-Development
Figure B. Flow scheme for Post-Development
Schemes above show a simplified run-off flow node to node, node 10 represents flow from node 7 to 17 (1.50 acre), node 22 represents node 21 to 22 (0.257 acre). Node 25 represents flow from node 1 to 2 (6.717 acre =6.218 existing + 0.499 acre developed) which is the undeveloped area and combined with flow from the developed area nodes 4, 5 and 25 (0.499 acre). Please see “Existing Conditions Q100 Calculations” in Attachment H for the pre-development conditions and see “Existing + Project Conditions Q100 Calculations” in Attachment I for the post-development conditions.

EXISTING CONDITIONS Q100
NODE AREA (Ac) Tc(MINS) I (in/Hr) C Q (cfs)
3 8.681 19 3.649 0.35 11.09
EXISTING + PROJECT CONDITIONS Q100
NODE AREA (Ac) Tc(MINS) I (in/Hr) C Q (cfs)
10 1.500 50 1.98 0.6 1.78
22 0.257 22 3.25 0.79 0.659
20 2.17
25 6.717 60 1.751 0.406 4.77
3 6.75
26 8.474 52 - - 6.75
RUNOFF DECREASE 4.34
CONFLUENCE NODE 10 AND 22
CONFLUENCE NODE 25 AND 20
Decrease of runoff is due to the implementation of sand filter and the StormChamberTM.

Developed area
25 5
26 3 20 22
10 3 2 1

*ROTATE VIEW