HomeMy WebLinkAboutHydrology
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HYDROLOGY REPORT
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TRACT 29036
TEMECULA, CA
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Prepared For:
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H.R. DEVELOPMENT CO.
1725 ORANGETREE LANE, SUITE C
REDLANDS, CA 92374
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Prepared By:
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ENGINEERING RESOURCES OF SOUTHERN CALIFORNIA, INC.
3550 E. FLORIDA AVENUE, SUITE B
HEMET, CA 92544
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January 2000
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RECEiVED
JAN 242000
en '{ Of- TEMtCtJLA
ENGINEERING DEPARTMENT
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HYDROLOGY REPORT
FOR
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TRACT 29036
TEMECULA, CA
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Prepared By:
ENGINEERING RESOURCES OF SOUTHERN CALIFORNIA, INC.
. 3550 E. FLORIDA AVENUE, SUITE B
HEMET, CA 92544
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Under the Supervision of
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MichaelJ. Stearns
Registered Civil Engineer No. 26406
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1. INTRODUCTION
1.1 SCOPE AND PURPOSE
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The purpose of this study is to determine the design flows for on-site drainage systems at the
proposed single family housing development in Tract 29036, City of Temecula, CA, and to
establish that these flows do not exceed those intended by the design of adjacent facilities.
1.2 SITE LOCATION AND DESCRIPTION
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The project is located in the city of Temecula, CA, bounded by Via La Vida to the north,
A venida Cima Del Sol to the south and Calle Plamas to the west. The site has been rough graded
with 2:1 slopes along its perimeter. There is an existing 24" RCP which enters from Avenida
Cima del Sol and carries 26.2 cfs onto the site in the 100-year event. An existing 30" RCP,
which enters from Calle Palmas, receives the drainage from the entire site near the southwesterly
portion of this tract.
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The project consists of the construction of24 single-family houses on approximately 6.3 acres.
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2.DESIGN DISCUSSION
2.1 DRAINAGE STANDARDS
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The drainage system was designed to meet or exceed the requirements of the City of Temecula,
CA. The Riverside County Hydrology Manual was used to determine the design storm.
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The piping system will convey the 100-year storm and must not exceed 59.6 cfs which includes
not only the drainage for this tract but the off-site flow from the existing 24" RCP which carries
26.2 cfs, as discussed earlier in this report. These flows were taken from the Storm Drain
Improvement Plans for the County of Riverside, Tract 22593 and 20153 respectively.
2.2 PROPOSED DRAINAGE
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Some ofthe flow will be collected at a proposed catch basin at the end ofthe cui de sac on "A"
Street and will be conveyed by a proposed storm drain pipe into the existing 30" RCP. The sub-
areas denoted "A" will drain via proposed Gunnite V-ditches and be collected in grates. Their
locations can be seen on the hydrology map which is attached at the end of this report.
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Another grated inlet will be used to collect the flow from sub-area "CI". This grate is to be
located at ajunction structure at the join to the existing 30" RCP.
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The remaining water will be carried onto Via La Vida by street gutter flow and travel in a
westerly direction.
3. HYDROLOGY
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3.1 DESIGN STORM
The 100-year rainfall event was selected as the design storm for this study.
3.2 METHOD OF STUDY
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This study was conducted using the modified rational method described in the Riverside County
Hydrology Manual. Flows were calculated by the Advanced Engineering Software model. The
computer run is included as Appendix B.
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The site was divided into a number of subareas, as shown on the hydrology map included with
this report, in order to determine flows at critical points. These subareas were classified as
commercial land use and soil type "D" was used in the model. These are the most conservative
assumptions.
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In addition, the conservative assumption was made that the site has a time of concentration
identical to the off site flow from the Avenida Cima Del Sol. The peak Avenida Cima Del Sol
flow is therefore treated as a base flow and added linearly to the flow generated by the site.
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The computer program computes rainfall intensity based on user input of the slope of the
logarithmic time-intensity curve and two points along that curve. The suggested value of 0.6 was
used for the slope. The lO-year and 100 year 1 hour intensities were read from Plate D4.l, from
the Riverside County Hydrology Manual. A copy ofthis plate can be found in Appendix A of
this report.
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4.
RESULTS AND CONCLUSIONS
4.1 STUDY OF 100 YEAR EVENT
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The 100-year event was studied and it was found that the total flow for this site into existing 30"
RCP is 38.3 cfs which is less than the allowable capacity of 59.6 cfs. The flows from the site to
the southerly gutter of Via La Visa are minor.
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This preliminary hydrology report shows that existing 24" RCP storm drain line on the southwest
comer ofthe project meets the drainage goals and requirements for the flows contributing to that
facility. However, the effects of contributing additional flows to Via La Vida have not been
studied.
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APPENDIX A:
REFERENCES & FIGURES
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REFERENCES
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1, "Rational Method Hydrology Computer Program Package (RA TSC2);" Advanced Engineering
Software; March, 1992.
2, " Storm Drain Plans Line 'r, Tract "593 County of Riverside"; To-Mac Engineering; approved
by Road Commissioners for Riverside County, CA; April, 1988,
3, "Storm Drain Improvement Plans for Avenida Cima Del Sol, Tract 20153 County of
Riverside"; Psomas & Associates; approved by Road Commissioners for Riverside County,
CA; August 1985,
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APPENDIX B:
. RATIONAL METHOD HYDROLOGY
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RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM BASED ON
RIVERSIDE COUNTY FLOOD CONTROL & WATER CONSERVATION DISTRICT
(RCFC&WCD) 1978 HYDROLOGY MANUAL
(c)copyright 1982-92 Advanced Engineering Software (aes) Ver. 1.3A Release Date: 3/06/92
License ID 1233
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Analysis prepared by:
ENGINEERING RESOURCES OF CALIFORNIA, INC,
3550 E, FLORIDA AVENUE, SUITE B
HEMET, CA 92544
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FILE NAME: 62385R4,DAT
TIME/DATE OF STUDY: 9:01 1/21/2000
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USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
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USER SPECIFIED STORM EVENT(YEAR) 100,00
SPECIFIED MINIMUM PIPE SIZE(INCH) 12,00
SPECIFIED PERCENT OF GRADIENTS (DECIMAL) TO USE FOR FRICTION SLOPE= ,90
10-YEAR STORM lO-MINUTE INTENSITY(INCH/HOUR) = 2.360
10-Y@ STORM 60-MINUTE INTENSITY(INCHlHOUR) = ,880
100-YEAR STORM IO-MINUTE INTENSITY(INCH/HOUR) = 3.480
100-YEAR STORM 60-MINUTE INTENSITY(INCH/HOUR) = 1.300
SLOPE OF IO-YEAR INTENSITY-DURATION CURVE =.5505732
SLOPE OF laO-YEAR INTENSITY-DURATION CURVE =,5495536
COMPUTED RAINFALL INTENSITY DATA:
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STORM EVENT = 100,00 I-HOUR INTENSITY(INCH/HOUR) = 1.3000
SLOPE OF INTENSITY DURATION CURVE = .5496
RCFC&WCD HYDROLOGY MANUAL 'IC"-V ALUES USED
NOTE: COMPUTECONFLUENCEVALUESACCORDINGTORCFC&WCD
HYDROLOGY MANUAL AND IGNORE OTHER CONFLUENCE
COMBINATIONS FOR DOWNSTREAM ANALYSES
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FLOW PROCESS FROM NODE 111.00 TO NODE 526,00 IS CODE = 21
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>>>>>RATIONAL METHOD INITIAL SUBAREA ANAL YSIS<<<<<
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ASSUMED INITIAL SUBAREA UNIFORM
DEVELOPMENT IS COMMERCIAL
TC = K*[(LENGTH**3)1(ELEV ATION CHANGE)]**,2
INITIAL SUBAREA FLOW-LENGTH = 200,00
UPSTREAM ELEVATION = 1132.80
DOWNSTREAM ELEVATION = 1114,70
ELEVATION DIFFERENCE = 18,10
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TC = .303*[( 200,OO**3)1( 18,10)]**,24,080
COMPUTED TIME OF CONCENTRATION INCREASED TO 5 MIN,
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.093
SOIL CLASSIFICATION IS ill"
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COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .8928
SUBAREA RUNOFF(CFS) ,91
TOTAL AREA(ACRES) ,20 TOTAL RUNOFF(CFS) ,91
FLOW PROCESS FROM NODE 526,00 TO NODE 526.00 IS CODE
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>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
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TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM I ARE:
TIME OF CONCENTRATION(MIN,) = 5,00
RAINFALL INTENSITY(INCH/HR) = 5,09
TOTAL STREAM AREA(ACRES) = .20
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PEAK FLOW RATE(CFS) AT CONFLUENCE
,91
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FLOW PROCESS FROM NODE 121.00 TO NODE 526,00 IS CODE = 21
>>>>>RATIONAL METHOD INITIAL SUBAREA ANAL YSIS<<<<<
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ASSUMED INITIAL SUBAREA UNIFORM
DEVELOPMENT IS COMMERCIAL
TC = K*[(LENGTH**3)/(ELEV ATION CHANGE)]**.2
INITIAL SUBAREA FLOW-LENGTH = 225,00
UPSTREAM ELEVATION = 1135,70
DOWNSTREAM ELEVATION = 1114,70
ELEVATION DIFFERENCE = 21.00
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TC = .303*[( 225.00**3)/( 21.00)]**,2 4,251
COMPUTED TIME OF CONCENTRATION INCREASED TO 5 MIN.
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5,093
SOIL CLASSIFICATION IS "D"
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = ,8928
SUBAREA RUNOFF(CFS) 1.36
TOTAL ARF-A(ACRES) ,30 TOTAL RUNOFF(CPS) 1.36
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FLOW PROCESS FROM NODE 526,00 TO NODE 526,00 IS CODE I
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>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM V ALUES<<<<<
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TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 5,00
RAINFALL INTENSITY(INCH/HR) = 5,09
TOTAL STREAM AREA(ACRES) = .30
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PEAK FLOW RATE(CFS) AT CONFLUENCE 1.36
CONFLUENCE DATA
STREAM RUNOFF Tc INTENSITY AREA
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ER (eFS) (MIN.) (INCH/HOUR)
1 ,91 5,00 5,093 .20
2 1.36 5.00 5,093 .30
(ACRE)
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IN THIS COMPUTER PROGRAM, THE CONFLUENCE VALUE USED IS BASED
ON THE RCFC&WCD FORMULA OF PLATE D-l AS DEFAULT VALUE. THIS
FORMULA
WILL NOT NECESSARILY RESULT IN THE MAXIMUM VALUE OF PEAK FLOW,
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RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS,
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** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 2,27 5,00 5.093
2 2,27 5,00 5.093
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COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) 2.27 Tc(MIN,) 5,00
TOTAL AREA(ACRES) ,50
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FLOW PROCESS FROM NODE 526,00 TO NODE 526,00 IS CODE
10
........ ... .,. ....... ... ........... ...... ... ... .... ... ... ... .... .,........ .....
>>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # I <<<<<
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FLOW PROCESS FROM NODE 211.00 TO NODE 525,00 IS CODE = 21
........ ... ... ...... ... ....... ... ... ...... ...... ... .,. ..... ... .... ... ... ......
>>>>>RATIONAL METHOD INITIAL SUBAREA ANAL YSIS<<<<<
....... ... .,.... ... ... .... ...... ... ... ..,.. ... ......... ......... ... ...... .....
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ASSUMED INITIAL SUBAREA UNIFORM
DEVELOPMENT IS COMMERCIAL
TC = K*[(LENGTH** 3)/(ELEV ATION CHANGE)]**,2
INITIAL SUBAREA FLOW-LENGTH = 695.00
UPSTREAM ELEVATION = 1127,00
DOWNSTREAM ELEVATION = 1118.40
ELEVATION DIFFERENCE = 8,60
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TC = .303*[( 695,00**3)/( 8,60)]**,2 9,997
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.481
SOIL CLASSIFICATION IS I'D"
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = ,8898
SUBAREA RUNOFF(CFS) 6,81
TOTALAREA(ACRES) 2,20 TOTALRUNOFF(CFS) 6,81
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FLOW PROCESS FROM NODE 525,00 TO NODE 525.00 IS CODE = 1
............. ... .......... ... ..................... ..... ..... ... ... ... ..... ....
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
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TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN,) = 10,00
RAINFALL INTENSITY (INCH/HR) = 3.48
TOTAL STREAM AREA (ACRES) = 2,20
PEAK FLOW RATE (CFS) AT CONFLUENCE = 6,81
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FLOW PROCESS FROM NODE
521.00 TO NODE 525,00 IS CODE 21
............... ... ....... ................ ...... .... ....... ... ............. ....
>>>>>RATIONAL METHOD INITIAL SUBAREA ANAL YSIS<<<<<
... .... ... .... ...... ....... .... ........... ... .... .... ... ... ... ......... ... ....
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ASSUMED INITIAL SUBAREA UNIFORM
DEVELOPMENT IS COMMERCIAL
TC = K*[(LENGTH**3)/(ELEV ATION CHANGE)]**,2
INITIAL SUBAREA FLOW-LENGTH = 380,00
UPST ELEVATION = 1126,50
DOWNSTREAM ELEVATION = 1118.40
ELEVATION DIFFERENCE = 8,10
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TC = .303*[( 380.00**3)/( 8.10)]**.2 7.043
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4,219
SOIL CLASSIFICATION IS "DI'
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = ,8914
SUBAREARUNOFF(CFS) 4,14
TOTAL AREA(ACRES) 1.10 TOTAL RUNOFF(CFS) 4.14
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FLOW PROCESS FROM NODE 525.00 TO NODE 525,00 IS CODE
... .... ... ................ ...... ... .............. ... ....... ..... ..... .........
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE V ARlOUS CONFLUENCED ST V ALUES<<<<<
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TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN,) = 7,04
RAINFALL INTENSITY(INCH/HR) = 4,22
TOTAL STREAM AREA(ACRES) = 1.10
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PEAK FLOW RATE(CFS) AT CONFLUENCE 4,14
** CONFLUENCE DATA **
STREAM RUNOFF Tc
NUMBER (CFS) (MIN,)
1 6,81 10.00 3.481 2,20
2 4.14 7,04 4,219 1.10
INTENSITY AREA
(INCH/HOUR) (ACRE)
. .... ............ .......... ... ........ ..... ....... ... ........ ..... '" .........
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IN THIS COMPUTER PROGRAM, THE CONFLUENCE VALUE USED IS BASED
ON THE RCFC&WCD FORMULA OF PLATE D-I AS DEFAULT VALUE, THIS
FORMULA
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WILL NOT NECESSARILY RESULT IN THE MAXIMUM VALUE OF PEAK FLOW.
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RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE
FORMULA USED FOR 2 STREAMS,
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** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc
NUMBER (CFS) (MIN,)
1 8,94 7,04 4,219
2 10,23 10,00 3.481
INTENSITY
(INCH/HOUR)
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COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW P-ATE(CFS) 10.23 Tc(MIN,) 10,00
TOTAL ARFA(ACP-ES) 3.30
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FLOW PROCESS FROM NODE
525,00 TO NODE 526,00 IS CODE = 3
>>>>>COMPLTTE PIPEFLOW TRAVELTIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
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DEPTH OF FLOW IN 12,0 INCH PIPE IS 9.2 INCHES PIPEFLOW VELOCITY(FEET/SEC,)
= 15,9
UPSTREAM NODE ELEVATION = 1118.40
DOWNSTREAM NODE ELEVATION = 1114,70 FLOWLENGTH(FEET) = 35,00
MANNING'S N = ,013 ESTIMATED PIPE DIAMETER(INCH) = 12,00 NUMBER OF PIPES
PIPEFLOW THRU SUBAREA(CFS) 10,23
TRAVEL TIME(MIN,) .04 TC(MIN,) = 10.03
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FLOW PROCESS FROM NODE
526,00 TO NODE 526,00 IS CODE
11
>>>>>CONFLUENCE MEMORY BANK # 1 WITH THE MAIN-STREAM MEMORY<<<<<
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MAIN STREAM CONFLUENCE DATA
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN,) (INCH/HOUR) (ACRE)
1 10,23 10,03 3.474 3.30
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MEMORY BANK # I CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 2,27 5,00 5,093 ,50
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IN THIS COMPUTER PROGRAM, THE CONFLUENCE VALUE USED IS BASED ON THE
RCFC&WCD FORMULA OF PLATE D-I AS DEFAULT VALUE, THIS FORMULA WILL
NOT NECESSARILY RESULT IN THE MAXIMUM VALUE OF PEAK FLOW,
.
PEAK FLOW RATE TABLE
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STREAM
NUMBER
I 7.37
2 11.78
RUNOFF Tc
(eFS) (MIN,)
5,00 5,093
10,03 3.474
INTENSITY
(INCH/HOUR)
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) 11.78 Tc(MIN,) 10m
TOTAL AREA(ACRES) 3,80
.
FLOW PROCESS FROM NODE 526,00 TO NODE 526,00 IS CODE 12
>>>>>CLEAR MEMORY BANK <<<<<
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FLOW PROCESS FROM NODE 526,00 TO NODE 615,00 IS CODE 3
>>>>>COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
.
DEPTH OF FLOW IN 36,0 INCH PIPE IS 25.3 INCHES
PIPEFLOW VELOCITY(FEET/SEC,) = 2,2
UPSTREAM NODE ELEVATION = 1114,70
DOWNSTREAM NODE ELEVATION = 1114,60
FLOWLENGTH(FEET) = 205,00 MANNING'S N ,013
ESTIMATED PIPE DIAMETER(INCH) = 36,00 NUMBER OF PIPES
PIPEFLOW THRU SUBAREA(CFS) 11.78
TRAVEL TIME(MIN,) 1.54 TC(MIN.) = 11.58
1
.
.
FLOW PROCESS FROM NODE 615,00 TO NODE 615,00 IS CODE
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
.
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN,) = 11.58
RAINFALL INTENSITY(INCH/HR) = 3,21
TOTAL STREAM AREA(ACRES) = 3,80
.
\"\
..
PEAK FLOW RATE(CFS) AT CONFLUENCE 11,78
.
.. ... ...... .... ................... ............ ... ........... .... ........ ......
FLOW PROCESS FROM NODE 611.00 TO NODE 615,00 IS CODE = 21
.... ... ... ........... ......... ... .... .................... .... .... ..... ... .....
>>>>>RATIONAL METHOD INITIAL SUBAREA ANAL YSIS<<<<<
....... ... ... .... ... ... ............ ............................ .... ....... ....
.
ASSUMED INITIAL SUBAREA UNIFORM
DEVELOPMENT IS COMMERCIAL
TC = K*[(LENGTH**3)/(ELEV ATION CHANGE)]**,2
.
INITIAL SUBAREA FLOW-LENGTH 140,00
UPSTREAM ELEVATION = 1123.30
DOWNSTREAM ELEVATION = 1114,60
ELEVATION DIFFERENCE = 8,70
,
I
!
.
.
.
TC = ,303*[( 140,00**3)/( 8,70)]**,2 3,814
COMPUTED TIME OF CONCENTRATION INCREASED TO 5 MIN,
100 YEAR RAINFALL INTENSITY(INCHlHOUR) = 5,093
SOIL CLASSIFICATION IS I'D"
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = ,8928
SUBAREA RUNOFF(CFS) ,45
TOTAL AREA(ACRES) .10 TOTAL RUNOFF(CFS) .45
... ... ... ... .... ... '" ... ........ .... ... ... .... ..... ... ...... ... ... ... ... ....,
FLOW PROCESS FROM NODE 615.00 TO NODE 615,00 IS CODE
!.
.... ... ... .......... ... .... ..... ... .... .,. ............ .... ...., ...... ... ... ...
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM V ALUES<<<<<
. ..... ... .,. .......... ... ... ..... .... ... ... .... ..... ... ... ... ... ... ... ..... ...
I.
I
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN,) = 5,00
RAINFALL INTENSTT (TNrw/mi?) =
y
TOTAL STREAM AREA(ACRES) ,10
PEAK FLOW RATE(CFS) AT CONFLUENCE .45
.
** CONFLUENCE DATA **
STREAM RUNOFF Tc
NUMBER (eFS) (MIN,)
1 11.78 11.58 3,211 3.80
2 .45 5,00 5,093 ,10
INTENSITY AREA
(INCHlHOUR) (ACRE)
.
IN THIS COMPUTER PROGRAM, THE CONFLUENCE VALUE USED IS BASED
.
\'b
.,
.
ON THE RCFC&WCD FORMULA OF PLATE D-I AS DEFAULT VALUE, THIS
FORMULA
WILL NOT NECESSARlL Y RESULT IN THE MAXIMUM VALUE OF PEAK FlOW,
.
RA1NF ALL 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)
I 5,54 5,00 5,093
2 12,06 11.58 3,211
.-
.
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) 12,06 Tc(MIN,) 11.58
TOTAL AREA(ACRES) 3,90
1-
....... .... ...... ....... ... ... ... ..... ..... ............... .... ... ..... ... .....
FLOW PROCESS FROM NODE 311,00 TO NODE 313,00 IS CODE 21
., ...... .... .... ....... ... ... ... ..... ..... ... ........ ... .......... ... ... ......
.
>>>>>RATIONAL METHOD INITIAL SUBAREA ANAL YSIS<<<<<
....... ....... ... ........ .......... ...... ..... ... ... ... ... .... ... ... ..........
.
ASSUMED INITIAL SUBAREA UNIFORM
DEVELOPMENT IS COMMERCIAL
TC = K*[(LENGTH** 3)/(ELEV ATION CHANGE)]**,2
INITIAL SUBAREA FLOW-LENGTH = 450,00
UPSTREAM ELEVATION = 1126.50
DOWNSTREAM ELEVATION = 1112.40
ELEVATION DIFFERENCE = 14,10
.
TC = ,303*[( 450,OO**3)1( 14.10)]**,2 6,977
100 YEAR RAINFALL INTENSITY(INCHlHOUR) = 4,241
SOIL CLASSIFICATION IS "DI
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = ,8915
SUBAREA RUNOFF(CFS) 6,05
TOTAL AREA(ACRES) 1,60 TOTAL RUNOFF(CFS) 6,05
.
.. ... .... ... .... ..... ... ..... ... ..... .................,............. ....,.....
FLOW PROCESS FROM NODE 212,00 TO NODE 227,00 IS CODE = 21
.... ... .......... .,............ .... ...... ..... ... ..... .... .............. ..,...
.
>>>>>RATIONAL METHOD INITIAL SUBAREA ANAL YSIS<<<<<
ASSUMED INITIAL SUBAREA RUNOFF
DEVELOPMENT IS COMMERCIAL
.
\~
.0
.
TC = K*[(LENGTH**3)/(ELEV ATION CHANGE)]** ,2
INITIAL SUBAREA FLOW-LENGTH = 310.00
UPSTREAM ELEVATION = 1122,20
DOWNSTREAM ELEVATION = 1111.20
ELEVATION DIFFERENCE = 11.00
.
TC = .303*[( 310.00**3)/( 11.00)]**,25,863
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4,667
SOIL CLASSIFICATION IS "DI
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = ,8922
SUBAREA RUNOFF(CFS) 2,50
TOTAL AREA(ACRES) ,60 TOTAL RUNOFF(CFS) 2,50
I
I.
... ........... ...... ... ........ .., ... ... ................ ... ...... ... ..... .....
FLOW PROCESS FROM NODE 411.00 TO NODE 425,00 IS CODE = 21
.. ..... ... ......... ... ..... ... ... .,. ... ... ..... ........... ... ...... ..... ......
.
I '
>>>>>RATIONAL METHOD INITIAL SUBAREA ANAL YSIS<<<<<
. ..... ..,..................., ... ... ...... ... ......... ... .... ... ....... ... .,...
.
ASSUMED INITIAL SUBAREA UNIFORM
DEVELOPMENT IS COMMERCIAL
TC = K*C(LENGTH**3)/(ELEV ATION CHANGE)]**,2
INITIAL SUBAREA FLOW-LENGTH = 270,00
UPSTREAM ELEVATION = 1127,20
DOWNSTREAM ELEVATION = 1106.50
ELEVATION DIFFERENCE = 20,70
.
TC = .303*[( 270,00**3)/( 20,70)]** ,2 4,756
COMPUTED TIME OF CONCENTRATION INCREASED TO 5 MIN,
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5,093
SOIL CLASSIFICATION IS "DI'
.
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = ,8928
SUBAREA RUNOFF(CFS) .45
TOTAL AREA(ACRES) ,10 TOTAL RUNOFF(CFS) .45
.
...... ... ......... -.. ........... ... ... .... ........... ... ... ... .......... ....,.
FLOW PROCESS FROM NODE 421.00 TO NODE 425,00 IS CODE = 21
>>>>>RATIONAL METHOD INITIAL SUBAREA ANAL YSIS<<<<<
.... .., ..... .... ...............,....... ...... ... ...................... ..... ...
.
ASSUMED INITIAL SUBAREA UNIFORM
DEVELOPMENT IS COMMERCIAL
TC = K*[(LENGTH**3)/(ELEV ATION CHANGE)]**,2
INITIAL SUBAREA FLOW-LENGTH = 365,00
.
2fJ
I.:
'.
UPSTREAM ELEVATION =
DOWNSTREAM ELEVATION =
ELEVATION DIFFERENCE =
1123.30
1106,50
16,80
.
I
TC = .303*[( 365,00**3)/( 16,80)]**,25,942
100 YEAR RAINFALL INTENSITY(INCHlHOUR) = 4,633
SOIL CLASSIFICATION IS I'D"
COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = ,8921
SUBAREA RUNOFF(CFS) =,83
TOTAL AREA (ACRES) =,20
TOTAL RUNOFF (CFS) =,83
.
END OF STUDY SUMMARY:
PEAK FLOW RATE(CFS) =,83 Tc(MIN,) =5,94
TOTAL AREA(ACRES) =,20
I.
END OF RATIONAL METHOD ANALYSIS
.
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'Z;\
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