HomeMy WebLinkAboutCUP 02-32; Bob Baker Vehicle Storeage Lot; Conditional Use Permit (CUP)HYDROLOGY AND HYDRAULIC REPORT
Bob Baker
Vehicle Storage Lot
Cannon Road and Avenida Encinas
City of Carlsbad
RECEIVED
JAN 3 0 2003
CITY OF CARLSBAD Prepared for:
PLANNING DEPT.
Bob Baker Enterprises, Inc.
591 Camino De La Reina, Suite 1100
San Diego, CA 92108
Prepared by:
bhA, Inc.
land planning, civil engineering, surveying
5115 Avenida Encinas, Suite L
Carlsbad, CA 92008-4387
(760) 931-8700
January 13,2003
W.O. 636-0851-600
TABLE OF CONTENTS
I. Discussion: Purpose and Scope
Project Description
Study Method
Conclusions
II. Calculations
A. Existing Hydrology
B. Proposed Hydrology
C. Vehicle Parking Lot -Detention Basin Calculations
III. Exhibits
Exhibit A: Existing Hydrology Map
Exhibit B: Proposed Hydrology Map
IV. References
L DISCUSSION
PURPOSE AND SCOPE:
The purpose of this report is to publish the results of hydrology and hydraulic computer
analysis for the proposed Vehicle Storage Lot for Bob Baker Enterprises, Inc. in the City of
Carlsbad. The scope is to study the existing and proposed hydrology and hydraulics as it
influences existing storm drain facilities in the vicinity during an 10-year frequency storm.
PROJECT DESCRIPTION:
The property, which is in the City of Carlsbad, is located at the street intersection of Cannon
Road and Avenida Encinas. The site is bordered by Cannon Road to the north, Avenida
Encinas to the east, and the SDNR raikoad right-of-way to the west. The 2.45-acre lot is zoned
for industrial use.
The project site is currently vacant, and was previously cleared. The lot drains into three
separate drainage basins. Basin No. 1 drains westerly from the ridge line, towards the SDNR
railroad right-of-way. Basin No. 2 drains northerly from the southeasterly comer of the site
to an existing curd inlet located at the intersection of Cannon Road and Avenida Encinas. The
remainder of the site, Basin No. 3, drains northerly onto Cannon Road to an existing curb inlet
at the intersection of Cannon Road and Avenida Encinas. The existing two curb inlets
previously mentioned are part of an existing storm drain system in the vicinity. See Exhibit "A"
for existing hydrology.
The proposed drainage system for vehicle storage lot will consist of a grass swale to collect
sheet flow from the storage lot and direct the flow to a catch basin (Basin No. 1). A 12-inch
HDPE pipe will be used to connect the catch basin to an existing curb inlet at the intersection
of Cannon Road and Avenida Encinas. The majority of the nm-off generated from the site
will be detained by using the parking lot as a detention basin. See detention basin calculations
in included in this report. The remainder of the site, Basins No. 2, 3 and 4 will drain as
previously described in the existing hydrology. See Exhibit "B" for proposed hydrology.
The method of analysis was based on the Rational Method according to the San Diego County
Hydrology Manual. The Hydrology and Hydraulic Analysis was done on HydroSoft by
Advanced Engineering Software.
The drainage basin areas were determined from the proposed grades shown on the proposed
Site Plan for Conditional Use Permit for the City of Carlsbad. The Rational Method provided
the following variable coefficients:
Soil type: Soil group C will be used for a composite runoff coefficient for the existing and
proposed hydrology.
Page 1
The runoff coefficient for commercial land use reflects a composite vaiue of landscaping and
street runoff per County of San Diego Hydrology Manual County.
Initial Time of concentration (in minutes) = Ti = 60x(11.9x(L^3)/H) ^0.385
RainfaU Intensity = I = 7.44x(P6)x(Tc) ^ 0.645
P6 for 10 year storm = 1.7
Exhibit "A" shows the existing hydrology. Exhibit "B" shows the proposed hydrology and on-
site drainage system for the Vehicle Storage Lot.
CONCLUSION:
The runoff at each point of discharge for the existing hydrology is listed below:
Node Discharge
30 1.6 cfs
50 1.6 cfs
70 0.5 cfs
Total 3.7 cfs
The accumulative discharge flow from the existing site is 3.7 cfs.
The runoff at each point of discharge for the proposed hydrology is listed below:
Node Discharge
60 2.6 cfs
80 0.1 cfs
100 0.1 cfs
Total 2.8 cfs
The accumulative discharge flow from the proposed vehicle parking lot is 2.8cfs, which is less
than the accumulative existing discharge flow of 3.7cfs. Pre-development drainage conditions
will be maintained by controlling the flow from on-site (i.e. the vehicle parking lot acting as a
detention basin) at the proposed catch basin (Node 250). The detention basin will have a
Page 2
maximum head of 3.6-feet, equivalent to a finish grade elevation of 45.6 shown on Exhibit "B".
The proposed vehicle lot will not have a significant impact on the existing storm drain system
in the vicinity.
Page 3
II. CALCULATIONS
II. CALCULATIONS
EXISTING HYDROLOGY
***************************************************************«************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-98 Advanced Engineering Software (aes)
Ver. l.SA Release Date: 01/01/98 License ID 1459
Analysis prepared by:
BHA INC.
5115 AVENDIA ENCINAS, SUITE L
CARLSBAD, CA 92008
••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••
************************** DESCRIPTION OF STUDY **************************
* EXISTING HYDROLOGY *
* *
* *
**************************************************************************
FILE NAME: 851-El.DAT
TIME/DATE OF STUDY: 15:28 1/10/2003
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
1985 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 10.00
6-HOUR DURATION PRECIPITATION (INCHES) = 1.700
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = .90
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED
NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED
****************************************************************************
FLOW PROCESS FROM NODE 10.00 TO NODE 20.00 IS CODE = 21
»»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««<
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .6700
INITIAL SUBAREA FLOW-LENGTH = 142.00
UPSTREAM ELEVATION = 47.90
DOWNSTREAM ELEVATION = 45.40
ELEVATION DIFFERENCE = 2.50
URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 7.639
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.408
SUBAREA RUNOFF(CFS) = .37
TOTAL AREA(ACRES) = .16 TOTAL RUNOFF(CFS) = .37
****************************************************************************
FLOW PROCESS FROM NODE 20.00 TO NODE 30.00 IS CODE = 6
»»>COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA««<
UPSTREAM ELEVATION = 45.40 DOWNSTREAM ELEVATION = 43.70
STREET LENGTH(FEET) = 390.00 CURB HEIGHT(INCHES) - 6.
STREET HALFWIDTH(FEET) = 23.00
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK = 21.50
INTERIOR STREET CROSSFALL(DECIMAL) = .020
OUTSIDE STREET CROSSFALL(DECIMAL) = .083
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
**TRAVELTIME COMPUTED USING MEAN FLOW(CFS) = .89
STREETFLOW MODEL RESULTS:
STREET FLOWDEPTH(FEET) = .28
HALFSTREET FLOODWIDTH(FEET) = 7.88
AVERAGE FLOW VELOCITY(FEET/SEC.) = 1.21
PRODUCT OF DEPTH&VELOCITY = .34
STREETFLOW TRAVELTIME(MIN) = 5.39 TC(MIN) = 13.03
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 2.415
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .6700
SUBAREA AREA(ACRES) = .64 SUBAREA RUNOFF(CFS) = 1.04
SUMMED AREA(ACRES) = .80 TOTAL RUNOFF(CFS) = 1.40
END OF SUBAREA STREETFLOW HYDRAULICS:
DEPTH(FEET) = .31 HALFSTREET FLOODWIDTH(FEET) = 9.23
FLOW VELOCITY(FEET/SEC.) = 1.45 DEPTH*VELOCITY = .45
****************************************************************************
FLOW PROCESS FROM NODE 100.00 TO NODE 100.00 IS CODE = 1
»»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««<
TOTAL NUMBER OF STREAMS = 3
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 13.03
RAINFALL INTENSITY(INCH/HR) = 2.42
TOTAL STREAM AREA(ACRES) = .80
PEAK FLOW RATE(CFS) AT CONFLUENCE = 1.40
****************************************************************************
FLOW PROCESS FROM NODE 40.00 TO NODE 50.00 IS CODE = 21
»»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««<
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .4500
INITIAL SUBAREA FLOW-LENGTH = 190.00
UPSTREAM ELEVATION = 47.90
DOWNSTREAM ELEVATION = 4 6.40
ELEVATION DIFFERENCE *= 1.50
URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 17.449
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 2.000
SUBAREA RUNOFF(CFS) = 1.20
TOTAL AREA(ACRES) = 1.33 TOTAL RUNOFF(CFS) - 1.20
****************************************************************************
FLOW PROCESS FROM NODE 100.00 TO NODE 100.00 IS CODE = 1
»»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««<
TOTAL NUMBER OF STREAMS - 3
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 17.45
RAINFALL INTENSITY(INCH/HR) = 2.00
TOTAL STREAM AREA(ACRES) = 1.33
PEAK FLOW RATE(CFS) AT CONFLUENCE = 1.20
****************************************************************************
FLOW PROCESS FROM NODE 60.00 TO NODE 70.00 IS CODE = 21
»»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««<
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .4500
INITIAL SUBAREA FLOW-LENGTH = 160.00
UPSTREAM ELEVATION = 48.20
DOWNSTREAM ELEVATION = 45.10
ELEVATION DIFFERENCE = 3.10
URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 11.872
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 2.564
SUBAREA RUNOFF(CFS) = .36
TOTAL AREA(ACRES) = .31 TOTAL RUNOFF(CFS) = .36
****************************************************************************
FLOW PROCESS FROM NODE 100.00 TO NODE 100.00 IS CODE = 1
»»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««<
»»>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES««<
TOTAL NUMBER OF STREAMS = 3
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 3 ARE:
TIME OF CONCENTRATION(MIN.) = 11.87
RAINFALL INTENSITY(INCH/HR) = 2.56
TOTAL STREAM AREA(ACRES) = .31
PEAK FLOW RATE(CFS) AT CONFLUENCE = .36
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 1.40 13.03 2.415 .80
2 1.20 17.45 2.000 1.33
3 .36 11.87 2.564 .31
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 3 STREAMS.
** PEAK FLOW RATJii TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 2.61 11.87 2.564
2 2.73 13.03 2.415
3 2.64 17.45 2.000
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 2.73 Tc(MIN.) = 13.03
TOTAL AREA(ACRES) = 2.4 4
END OF STUDY SUMMARY:
PEAK FLOW RATE(CFS) = 2.73 Tc(MIN.) = 13.03
TOTAL AREA(ACRES) = 2.44
END OF RATIONAL METHOD ANALYSIS
n. CALCULATIONS
PROPOSED HYDROLOGY
M
1
1
1
1
]
I
****************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-98 Advanced Engineering Software (aes)
Ver. 1.5A Release Date: 01/01/98 License ID 1459
Analysis prepared by:
BHA INC.
5115 AVENDIA ENCINAS, SUITE L
CARLSBAD, CA 92008
••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••
************************** DESCRIPTION OF STUDY **************************
* proposed hydrology *
**************************************************************************
FILE NAME: 851-Pl.DAT
TIME/DATE OF STUDY: 13:30 1/13/2003
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
1985 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENT(YEAR) = 10.00
6-HOUR DURATION PRECIPITATION (INCHES) = 1.700
SPECIFIED MINIMUM PIPE SIZE(INCH) = 12.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = .90
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED
NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED
****************************************************************************
FLOW PROCESS FROM NODE 10.00 TO NODE 20.00 IS CODE = 21
»»>RAT10NAL METHOD INITIAL SUBAREA ANALYSIS««<
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .7300
INITIAL SUBAREA FLOW-LENGTH = 215.00
UPSTREAM ELEVATION = 48.00
DOWNSTREAM ELEVATION = 45.40
ELEVATION DIFFERENCE = 2.60
URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 9.166
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.030
SUBAREA RUNOFF(CFS) = .46
TOTAL AREA(ACRES) = .21 TOTAL RUNOFF(CFS) = .46
****************************************************************************
FLOW PROCESS FROM NODE 20.00 TO NODE 60.00 IS CODE = 6
»»>COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA««<
UPSTREAM ELEVATION = 45.40 DOWNSTREAM ELEVATION = 43.70
STREET LENGTH(FEET) = 390.00 CURB HEIGHT(INCHES) = 6.
STREET HALFWIDTH(FEET) = 23.00
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK = 21.50
INTERIOR STREET CROSSFALL(DECIMAL) = .020
OUTSIDE STREET CROSSFALL(DECIMAL) = .083
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
**TRAVELTIME COMPUTED USING MEAN FLOW(CFS) = .89
STREETFLOW MODEL RESULTS:
STREET FLOWDEPTH(FEET) = .28
HALFSTREET FLOODWIDTH(FEET) = 7.88
AVERAGE FLOW VELOCITY(FEET/SEC.) = 1.21
PRODUCT OF DEPTH&VELOCITY = .34
STREETFLOW TRAVELTIME(MIN) = 5.39 TC(MIN) = 14.56
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 2.248
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .6900
SUBAREA AREA(ACRES) = .53 SUBAREA RUNOFF(CFS) = .82
SUMMED AREA(ACRES) = .74 TOTAL RUNOFF(CFS) = 1.29
END OF SUBAREA STREETFLOW HYDRAULICS:
DEPTH(FEET) = .31 HALFSTREET FLOODWIDTH(FEET) = 9.23
FLOW VELOCITY(FEET/SEC.) = 1.33 DEPTH*VELOCITY = .41
****************************************************************************
FLOW PROCESS FROM NODE 60.00 TO NODE 60.00 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.) = 14.56
RAINFALL INTENSITY(INCH/HR) = 2.25
TOTAL STREAM AREA(ACRES) = .74
PEAK FLOW RATE(CFS) AT CONFLUENCE = 1.29
****************************************************************************
FLOW PROCESS FROM NODE 30.00 TO NODE 40.00 IS CODE = 21
»»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««<
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .8300
INITIAL SUBAREA FLOW-LENGTH = 200.00
UPSTREAM ELEVATION = 48.30
DOWNSTREAM ELEVATION = 4 6.40
ELEVATION DIFFERENCE = 1.90
URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 6.992
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.608
SUBAREA RUNOFF(CFS) = 1.47
TOTAL AREA(ACRES) = .49 TOTAL RUNOFF(CFS) = 1.47
****************************************************************************
FLOW PROCESS FROM NODE 40.00 TO NODE 50.00 IS CODE = 51
»»>COMPUTE TRAPEZOIDAL CHANNEL FLOW««<
»»>TRAVELTIME THRU SUBAREA««<
UPSTREAM NODE ELEVATION = 46.40
DOWNSTREAM NODE ELEVATION = 44.60
CHANNEL LENGTH THRU SUBAREA(FEET) = 345.00
CHANNEL SLOPE = .0052
CHANNEL BASE(FEET) = 3.00 "Z" FACTOR = .500
MANNING'S FACTOR = .030 MAXIMUM DEPTH(FEET) = .50
CHANNEL FLOW THRU SUBAREA(CFS) = 1.47
FLOW VELOCITY(FEET/SEC) = 1.47 FLOW DEPTH(FEET) = .32
TRAVEL TIME(MIN.) = 3.91 TC(MIN.) = 10.90
****************************************************************************
FLOW PROCESS FROM NODE 50.00 TO NODE 50.00 IS CODE = 8
»»>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW««<
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 2.710
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .8200
SUBAREA AREA(ACRES) = 1.00 SUBAREA RUNOFF(CFS) = 2.22
TOTAL AREA(ACRES) = 1.49 TOTAL RUNOFF(CFS) = 3.69
TC(MIN) = 10.90
+ +
I FLOW FROM VEHICLE PARKING LOT - DETENTION BASIN |
I • I
I I + .^.
****************************************************************************
FLOW PROCESS FROM NODE 50.00 TO NODE 50.00 IS CODE = 7
»»>USER SPECIFIED HYDROLOGY INFORMATION AT NODE««<
USER-SPECIFIED VALUES ARE AS FOLLOWS:
TC(MIN) = 23.00 RAIN INTENSITY(INCH/HOUR) = 1.67
TOTAL AREA(ACRES) = 1.4 9 TOTAL RUNOFF(CFS) = 1.60
****************************************************************************
FLOW PROCESS FROM NODE 50.00 TO NODE 60.00 IS CODE = 4
»»>COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA««<
>»»USING USER-SPECIFIED PIPESIZE««<
DEPTH OF FLOW IN 18.0 INCH PIPE IS 2.9 INCHES
PIPEFLOW VELOCITY(FEET/SEC.) = 8.5
UPSTREAM NODE ELEVATION = 42.10
DOWNSTREAM NODE ELEVATION = 4 0.40
FLOWLENGTH(FEET) = 37.00 MANNING'S N = .010
GIVEN PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES =
PIPEFLOW THRU SUBAREA(CFS) = 1.60
TRAVEL TIME(MIN.) = .07 TC(MIN.) = 23.07
****************************************************************************
FLOW PROCESS FROM NODE 60.00 TO NODE 60.00 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.) = 23.07
RAINFALL INTENSITY(INCH/HR) = 1.67
TOTAL STREAM AREA(ACRES) = 1.4 9
PEAK FLOW RATE(CFS) AT CONFLUENCE = 1.60
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 1.29 14.56 2.248 .74
2 1.60 23.07 1.670 1.49
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 2.48 14.56 2.248
2 2.56 23.07 1.670
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 2.56 Tc(MIN.) = 23.07
TOTAL AREA(ACRES) = 2.23
****************************************************************************
FLOW PROCESS FROM NODE 60.00 TO NODE 60.00 IS CODE = 1
»»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««<
TOTAL NUMBER OF STREAMS = 3
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 23.07
RAINFALL INTENSITY(INCH/HR) = 1.67
TOTAL STREAM AREA(ACRES) = 2.23
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.56
****************************************************************************
FLOW PROCESS FROM NODE 70.00 TO NODE 80.00 IS CODE = 21
»»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««<
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .4 500
INITIAL SUBAREA FLOW-LENGTH = 22.00
UPSTREAM ELEVATION = 52.00
DOWNSTREAM ELEVATION = 45.00
ELEVATION DIFFERENCE = 7.00
URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 1.732
*CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH
DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED.
TIME OF CONCENTRATION ASSUMED AS 6-MINUTES
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.982
SUBAREA RUNOFF(CFS) = .14
TOTAL AREA(ACRES) = .08 TOTAL RUNOFF(CFS) = .14
****************************************************************************
FLOW PROCESS FROM NODE 80.00 TO NODE 80.00 IS CODE = 1
»»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««<
TOTAL NUMBER OF STREAMS = 3
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 6.00
RAINFALL INTENSITY(INCH/HR) = 3.98
TOTAL STREAM AREA(ACRES) = .08
PEAK FLOW RATE(CFS) AT CONFLUENCE = .14
****************************************************************************
FLOW PROCESS FROM NODE 90.00 TO NODE 100.00 IS CODE = 21
»»>RATIONAL METHOD INITIAL SUBAREA AN7VLYSIS««<
*USER SPECIFIED(SUBAREA):
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .4500
INITIAL SUBAREA FLOW-LENGTH = 110.00
UPSTREAM ELEVATION = 47.40
DOWNSTREAM ELEVATION = 4 6.90
ELEVATION DIFFERENCE = .50
URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 15.959
*CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH
DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED.
10 YEAR RAINFALL INTENSITY(INCH/HOUR) = 2.119
SUBAREA RUNOFF(CFS) = .13
TOTAL AREA(ACRES) = .14 TOTAL RUNOFF(CFS) = .13
****************************************************************************
FLOW PROCESS FROM NODE 100.00 TO NODE 100.00 IS CODE = 1
»»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««<
»»>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES««<
TOTAL NUMBER OF STREAMS = 3
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 3 ARE:
TIME OF CONCENTRATION(MIN.) = 15.96
RAINFALL INTENSITY(INCH/HR) = 2.12
TOTAL STREAM AREA(ACRES) = .14
PEAK FLOW RATE(CFS) AT CONFLUENCE = .13
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 2.56 23.07 1.670 2.23
2 .14 6.00 3.982 .08
3 .13 15.96 2.119 .14
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 3 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 1.29 6.00 3.982
2 2.22 15.96 2.119
3 2.72 23.07 1.670
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 2.72 Tc(MIN.) = 23.07
TOTAL AREA(ACRES) = 2.45
END OF STUDY SUMMARY:
PEAK FLOW RATE(CFS) = 2.72 Tc(MIN.) = 23.07
TOTAL AREA(ACRES) = 2.45
END OF RATIONAL METHOD ANALYSIS
II. CALCULATIONS
VEHICLE PARKING LOT • DETENTION BASIN CALCULATIONS
bhA lnc
land planning, civil engineering, surveying
5115 Avenida Encinas, Suite L, Carlsbad, CA 92008
(760)931-8700 Fax (760) 931-7780
Date , / 1 W.O. ^
C?///5/r>^ lO-ite-oi^l-Uo^ Sheet of
bhA lnc
land planning, civil engineering, surveying
5115 Avenida Encinas, Suite L, Carlsbad, CA 92008
(760)931-8700 Fax (760) 931-7780
Checked by Client bhA lnc
land planning, civil engineering, surveying
5115 Avenida Encinas, Suite L, Carlsbad, CA 92008
(760)931-8700 Fax (760) 931-7780
Job Description
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*************************************************************««**«**********
HYDRAULICS ELEMENTS - II PROGRAM PACKAGE
STORAGE BASIN HYDROGRAPH ROUTING MODEL
****************************************************************************
(c) Copyright 1983-98 Advanced Engineering Software (aes)
Ver. 7.1 Release Date: 01/01/98 License ID 1459
Analysis prepared by:
BHA
5115 AVENIDA ENCINAS
SUITE L
CARLSBAD, CA 92008
************************** DESCRIPTION OF STUDY **************************
* DETENTION POND - 6" PIPE *
* *
* *
**************************************************************************
FILE NAME: 851-P6.DAT
TIME/DATE OF STUDY: 10:11 1/13/2003
ENTERED INFORMATION:
TOTAL NUMBER OF INFLOW HYDROGRAPH INTERVALS = 33
CONSTANT HYDROGRAPH TIME UNIT(MINUTES) = 1.000
ASSUMED INITIAL DEPTH(FEET) IN STORAGE BASIN = .00
ENTERED INFLOW HYDROGRAPH ORDINATES(CFS):
•INTERVAL FLOW *INTERVAL FLOW *INTERVAL
* NUMBER (CFS) * NUMBER (CFS) * NUMBER
FLOW
(CFS)
* 1 .33* 2 .66* 3 , 99*
* 4 1.32* 5 1.65* 6 1. 98*
* 7 2.31* 8 2.64* 9 2. 97*
* 10 3.30* 11 3.70* 12 3. 53*
* 13 3.37* 14 3.20* 15 3. 03*
* 16 2.86* 17 2.69* 18 2. 52*
* 19 2.35* 20 2.18* 21 2. 01*
* 22 1.84* 23 1.67* 24 1. 50*
* 25 1.33* 26 1.16* 27 99*
* 28 .82* 29 . 65* 30 48*
* 31 .31* 32 .14* 33 • 00*
DEPTH-VS.-STORAGE AND DEPTH-VS.-DISCHARGE INFORMATION:
TOTAL NUMBER OF BASIN DEPTH INFORMATION ENTRIES = 6
*BASIN-DEPTH STORAGE OUTFLOW
* (FEET) (ACRE-FEET) (CFS)
* .000 .000 .000**
* 2.000 .002 1.210**
* 4.000 .110 1.860**
**BASIN-DEPTH STORAGE OUTFLOW
** (FEET) (ACRE-FEET) (CFS)
1.000
3.000
5.000
.001
.020
.430
.700*
1.570*
2.110*
****************************************************************************
INITIAL BASIN DEPTH(FEET) = .00
INITIAL BASIN STORAGE(ACRE-FEET) =
INITIAL BASIN OUTFLOW(CFS) =
.00
,00
BASIN STORAGE, OUTFLOW AND DEPTH ROUTING VALUES;
INTERVAL
NUMBER
1
2
3
4
5
6
{S-0*DT/2}
(ACRE-FEET)
.00000
.00052
.00117
.01892
.10872
.42855
{S+0*DT/2)
(ACRE-FEET)
.00000
.00148
.00283
.02108
.11128
.43145
WHERE S=STORAGE{AF);0=0UTFL0W(AF/MIN.);DT=UNIT(MIN.)
*UNIT-HYDROGRAPH STORAGE-BASIN ROUTING*
NOTE: COMPUTED BASIN DEPTH, OUTFLOW, AND STORAGE QUANTITIES
OCCUR AT THE GIVEN TIME. BASIN INFLOW VALUES REPRESENT THE
AVERAGE INFLOW DURING THE RECENT HYDROGRAPH UNIT INTERVAL.
GRAPH NOTATION: "I"=MEAN UNIT INFLOW; "0"=OUTFLOW AT GIVEN TIME
TIME INFLOW OUTFLOW
(HOURS) (CFS) (CFS)
STORAGE
(ACRE-FT)
02 .3 .2 .000 .01
[BASIN DEPTH(FEET) = .3]
03 .7 .5 .001 01 .
[BASIN DEPTH(FEET) = .7]
05 1.0 .8 .001 0 I
[BASIN DEPTH(FEET) = 1 2]
07 1.3 1 .1 .002 .0 I
[BASIN DEPTH(FEET) = 1 .7]
08 1.6 1 .2 .002 . 0 I
[BASIN DEPTH(FEET) = 2 0]
10 2.0 1 .2 .003 . 0
[BASIN DEPTH(FEET) = 2 1]
12 2.3 1 .3 .005 . 0
[BASIN DEPTH(FEET) = 2 2]
13 2.6 1 .3 .007 . 0
[BASIN DEPTH(FEET) = 2 3]
15 3.0 1 4 .009 . 0
[BASIN DEPTH(FEET) = 2 4]
17 3.3 1 .4 .012 0
[BASIN DEPTH(FEET) = 2 5]
18 3.7 1 5 .015 0
[BASIN DEPTH(FEET) = 2 7]
20 3.5 1 5 .018 0
[BASIN DEPTH(FEET) = 2 9]
22 3.4 1 6 020 0
[BASIN DEPTH(FEET) = 3 0]
23 3.2 1 6 022 0
1
[BASIN DEPTH(FEET) = 3 .0]
.25 3.0 1 .6 .024 . 0 .
[BASIN DEPTH(FEET) = 3 .0]
.27 2.9 1 .6 .026 . 0 .
[BASIN DEPTH(FEET) = 3 .1]
.28 2.7 1 . 6 .028 . 0 .
[BASIN DEPTH(FEET) = 3 .1]
.30 2.5 1 .6 .029 . 0 .
[BASIN DEPTH(FEET) = 3 .1]
.32 2.3 1 .6 .030 . 0 .
[BASIN DEPTH(FEET) = 3 .1]
33 2.2 1 .6 .031 . 0 . I
[BASIN DEPTH(FEET) = 3 .1]
35 2.0 1 .6 .031 . 0 .1
[BASIN DEPTH(FEET) = 3 .1]
37 1.8 1 .6 .032 . 0 I.
[BASIN DEPTH(FEET) = 3 .1]
38 1.7 1 .6 .032 . 01 .
[BASIN DEPTH(FEET) = 3 .1]
40 1.5 1 .6 .032 . 10 .
[BASIN DEPTH(FEET) = 3 .1]
42 1.3 1 .6 .031 . . I 0 .
[BASIN DEPTH(FEET) = 3 1]
43 1.2 1 .6 .031 . .10.
[BASIN DEPTH(FEET) = 3 1]
45 1.0 1 .6 .030 . I 0 .
[BASIN DEPTH(FEET) = 3 1]
47 .8 1 6 .029 . 1. 0 .
[BASIN DEPTH(FEET) = 3 1]
48 .6 1 6 .027 . I . 0 .
[BASIN DEPTH(FEET) = 3 1]
50 .5 1 6 .026 . ] [ . 0 .
[BASIN DEPTH(FEET) = 3 1]
52 .3 1 6 .024 . I 0 .
[BASIN DEPTH(FEET) = 3 0]
53 .1 1 6 022 .1 0 .
[BASIN DEPTH(FEET) = 3. 0]
55 .0 1. 6 020 I 0 .
[BASIN DEPTH(FEET) = 3. 0]
57 .0 1. 5 018 I 0 .
[BASIN DEPTH(FEET) = 2. 9]
58 .0 1. 5 016 I 0
[BASIN DEPTH(FEET) = 2. 8]
60 .0 1. 4 014 I 0
[BASIN DEPTH(FEET) = 2. 6]
62 .0 1. 4 012 I 0
[BASIN DEPTH(FEET) 2. 5]
63 .0 1. 4 010 I . 0
[BASIN DEPTH(FEET) = 2. 4]
65 .0 1. 3 008 I . 0
[BASIN DEPTH(FEET) = 2. 3]
67 .0 1. 3 006 I . 0
[BASIN DEPTH(FEET) = 2. 2]
68 .0 1. 3 004 I . 0
[BASIN DEPTH(FEET) = 2. 1]
70 .0 1. 2 003 I . 0
[BASIN DEPTH(FEET) = 2. 0]
72 .0 .8 .001 I
[BASIN DEPTH(FEET) = 1.3]
73 .0 .3 .000 I
[BASIN DEPTH(FEET) = .5]
75 .0 .1 .000 0
[BASIN DEPTH(FEET) = .2]
77 .0 .0 .000 0
[BASIN DEPTH(FEET) = .1]
78 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
80 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
82 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
83 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
85 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
87 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
88 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
90 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
92 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
93 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
95 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
97 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
98 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 00 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 02 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 03 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 05 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 07 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 08 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 10 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 12 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 13 .0 .0 .000 0
(BASIN DEPTH(FEET) = .0]
1 15 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 17 .0 .0 .000 0
[BASIN DEPTH(FEET) = .0]
1 18 .0 .0 .000 0
III. EXHIBITS
IV. REFERENCES
INTEKSITY-DUBATION DESIGN CHART
—"I—^iTrlTfTTTi.Trh I'-' niiiliiinii..i;i:itrntr:. . •.' V i 'i.i-j.i u i H i nnlini
y Equation: I •= 7,44 D "•^'^^
I = Intensity (In./Hr.)
= 6 Hr, Precipitation (In.)
Directions for Application:
1) From precipitation naps determine 6 hr. and
24 hr. amounts for the selected frequency.
These maps are printed in the County Hydrolony
Manual (10, 50 nnd 100 yr. maps included in thi
Design and Procedure Manual).
2) Adjust 6 hr. precipitation (if necessary) so
that it is within the range of 45% to 65% of
the 24 hr. precipitation. (Not r.pplicable
to Desert)
3) Plot 6 hr. precipitation on the right side
of the chart.
4) Drav/ a line through the point parallel to the
plotted lines.
5) This linr is the intensity-duration curve for
the locacion being analyzed.
Application Form:
0) Selected Frequency yr.
1) Pe = A£^1n.. P24= 2J£_. ^*
2) Adjusted *Pg=
3) t^ = min.
/.6
24
in.
4) I = in/hr.
*Not Applicable to Desert Region
APPENDIX XI
IV-A-14
COU.VTY OF SAN OIEGO .
DEPART'MENT OF SANITATIOM &
FLOOD COfJTROL 10-YEAR 24-HOUR PRECiPITATION
'-20-/ISOPLUViALS
PRECIPiTATiOiJ IfJ
]F 10-YEAR 24-HOUR
WTiiS QF AW WXW
33'
Prfp^
U.S. DEPARTMEII
NATtO.VAL OCEANIC AND AT
SPECIAL STUDIES DRANCII. OFFICE OK 1 h'
COUNTY OF SAN DIEGO
DEPARTMENT OF SANITATION C
FLOOD CONTROL 10-YEAR B-muti pmmmmn
33"
16- iSOPLUViALS OF 10-YEAR G-iiO'Jn
PE|ECIPITflT!Oi.! Ul TENTHS OF AfJ lf,ICH
... "^"^'O^'-^L OCEANIC AND Al
SPECIAL STODIES DRANCII. OFFICE OF
C-J
C
t
Prtpijrrd by
U.S. DEPARTMENfr OF COMMERCE
30'
OSPIIERIC AD.MINISTRATION
"h-DROLOCy. NATIONAL WEATHER SERVICE
116*
RUNOFF COEFFICIENTS (RATIONAL METHOD)
LAND USE Coefficient, C
Soil Group (1)
A B C D
Undeveloped .30 .35 .40 .45
Residential:
Rural .50 . 35 .40 .45
Single Family .40 .45 .50 .55
Multi-Units .45 .50 .60 . 70
Mobile Homes (2) .45 .50 .55 .65
Commercial (2) .70 . 75 .80 .85
80% Impervious
Industrial (2) .80 .85 .90 .95
90% Impervious
NOTES:
(1) Obtain soil group from maps on file with the Department of Sanitation
and Flood Control.
(2) Where actual conditions deviate significantly from the tabulated
imperviousness values of 80% or 90%, the values given for coefficient
C, may be revised by multiplying 80% or 90% by the ratio of actual
imperviousness to the tabulated imperviousness. However, in no case
shall the final coefficient be less than 0.50. For example: Consider
commercial property on D soil group.
Actual imperviousness = 50%
Tabulated imperviousness = 80%
Revised C = |° X 0.85 = 0.53
APPENDIX IX
I
I
- SOO
- iao
- £00 \
\
Fee/
—S'O a a
—4aao
—3ooo
—zaao
£Qa/?r/OA/
Tc- '^^^
7c--
e/fcc^/re s/ooe /me (See Appendix X-3) j.
M//as
/O —
•SOO
• 400
• 300
• 20O
\
\
•/oo
4-
3-
2-
\
\ -
• so
40
.30
•ZO
O.S.
NOTE
poTNATURAr^TE^FEDsl
B ADD TEN MINUTES TO fi
! COMPUTED TIME OF CON- E
JCENTRATION. _j
/O
— 5
^ee/
4-
-SOOO
. 30O0
\
-2000
•/SOO
/600
/400
/200
- /OOO 900
800
70O
£00
-S'OO
\
\
— 4dO
— 3DO
200
Mf/7ty/es
/BO
/20
./OO
50
• 80
70
-£0
^O
40
30
-20
•/8
• /£
./4
/2
- /O
9
8
7
•£
SAN DIEGO COUNTY
DEPARTMENT OF SPECIAL DISTRICT SERVICES
RE-SiGN fva.'VNUAL-
APPROVED O' /f^r^^'^^i'^-^ <C^^j>
NOMOGRAPH FOR DETERMINATfON
OF TIME OF CONCENTRATION (Tc)
FOR NATURAL WATERSHEDS
APPENDIX X-A
-A-10 Rev. 5/81
D/i//c/e
- - SAN DIEGO COUNTY
DEPARTMENT OF SPECIAL DISTRICT SERVICES
&£SLGN MANUAL.
APPROVED ..2l4z^l4^?<^s^bi£^E^^_
COMPUTATION OF EFFECTIVE SLOPE
FOR NATURAL WATERSHEDS
APPENDIX X-B
.S'OO
£xo/77p/e ••
C/ye/7 : liT/rg/A a/'/7okv ' SO^ //.
£/o/D£ - /^%
CoeMc/e/?/ o/ £'a/7o/^. C-.SO
^'caaf •• iJi^^A/t^nd£/oyyf/n7e '/^ Jif//7£//^s
SAN DIEGO COUNTY
DEPARTMENTOF SPECIAL DISTRICT SERVICES
DESJGN iV1>\NUAL
APPROVED • '/ 'v^','' ^- ••i^t.^.jc;'^
URBAN AREAS OVERLAND TIME
OF FLOW CURVES
DATE n///S9 APPENDIX X-C