Loading...
HomeMy WebLinkAboutCT 05-12; Ocean Street Residences; Hydrology Report Ocean Street Condominium; 2005-05-11HYDROLOGY REPORT OCEAN STREET CONDOMINIUM 2303-2327 Ocean Street City of Carlsbad Prepared for: 2303 Investors, LP. 1020 Prospect Street, Suite 314 La Jolla, CA 92037 Prepared by: brlA, Inc. land planning, civil engineering, surveying 5115 Avenida Encinas, Suite L Carlsbad, CA 92008-4387 (760) 931-8700 RECEIVED JUN 1 0 2005 CITY OF CARLSBAD PLANNING DEPT May 11, 2005 W.O. 724-0978-400 CT TABLE OF CONTENTS I. Discussion II. Calculations A. Existing 100-Year Storm Hydrology B. Developed 100-Year Storm Hydrology III. Exhibits A. Existing Hydrology Map B. Developed Hydrology Map IV. References I. DISCUSSION DISCUSSION: This is a Hydrology Report for the proposed Tentative Map for the Ocean Street Condominium project in the City of Carlsbad. This 3.1 acre site is located on Ocean Street between Mountain View Drive and Garfield Street. This Development proposes the construction of 35 residential condominium units. In the existing condition, the project site is occupied by several apartment buildings and parking spaces. The runoff from project's frontage, Ocean Street, flows to two existing curb inlets in Ocean Street, just east and west of the site. The runoff from the site flows in a northwestern direction, through a series of pipes and gutters in the apartment complex, and outlets into Buena Vista Lagoon. In the proposed condition, the apartment buildings and garage structure will be demolished and removed. A 35-unit condominium complex with underground parking garage and a paved driveway will be constructed. The runoff from the driveway is collected by the proposed rolled curb and channeled to a curb opening near the fire truck turn around. From the curb opening, the driveway's runoff is filtered and released into a proposed grassy swale along the northern boundary. The runoff from the structure, hard scape, and pool area will be collected by a series of roof and yard drains and piped to the northern portion of the property. The runoff is released into the proposed grassy swale where it is filtered and released into Buena Vista Lagoon. Drainage basin areas were determined from the proposed finish grades as shown on the Tentative Parcel Map for the above referenced project. Using the Rational Method, the on- site Runoff Coefficients were determined as: User Specified Storm Event (Year) = 100 6-Hour Duration Precipitation (Inches) = 2.6 Soil Classification of "A" will be assumed for the drainage basins for the hydrology calculation. Existing Runoff Coefficient = Residential (43 Du/Ac) = 0.76 (80% impervious) Developed Runoff Coefficient = Residential (43 Du/Ac) = 0.76 (80% impervious) The exhibits show the proposed on-site drainage system, subarea, acreage, and nodal points. This study considers the runoff for a 100-year storm frequency and the on-site drainage system shown in the Tentative Map. The above referenced project is designed for a 100-year storm frequency. The actual size and location of the pipe will be design during the final engineering. The summary of existing and developed runoff is in Table 1-1 IH M Table 1-1 Summary of Existing and Developed Runoff Node 3 Existing (cfs/ac) 16.8/3.23 Developed (cfs/ac) 12.74/3.23 CONCLUSION: The proposed design does not adversely affect the surrounding properties. The storm drain system adequately drains the proposed project in a 100-year storm event. II. CALCULATIONS II. CALCULATIONS A. EXISTING 100-YEAR STORM HYDROLOGY ****************************************************************************** i RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT • 2003,1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-2003 Advanced Engineering Software (aes) 1 Ver. 1.5A Release Date: 01/01/2003 License ID 1459 1 Analysis prepared by: 1 bHA, Inc. 5115 Avenida Encinas, Suite L Carlsbad, Calif 92008 FILE NAME: K:\HYDRo\o978\Ei.DATnnmnnDDannnDnnnDDDDnnnnQnnnon TIME/DATE OF STUDY: 09:39 05/10/2005 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: 2003 SAN DIEGO MANUAL CRITERIA „ USER SPECIFIED STORM EVENT(YEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 2.600 • SPECIFIED MINIMUM PIPE SIZE(INCH) = 8.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.90 - 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)HI _____ _ 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150 m 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.* "l-I + .1 OCEAN STREET CONDOMINIUM - W.O. 724-0978-400 I | EXISTING 100 YEAR HYDROLOGY I .1 EXISTING BASIN 1 | - FLOW PROCESS FROM NODE 1.00 TO NODE 2.00 IS CODE = 21 " >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« ' RESIDENTAIL (43. DU/AC OR LESS) RUNOFF COEFFICIENT = .7600 SOIL CLASSIFICATION IS "A" S.C.S. CURVE NUMBER (AMC II) = 86 . INITIAL SUBAREA FLOW-LENGTH(FEET) = 70.00 UPSTREAM ELEVATION(FEET) = 38.00 " DOWNSTREAM ELEVATION(FEET) = 34.00 ELEVATION DIFFERENCE(FEET) = 4.00 " SUBAREA OVERLAND TIME OF FLOW(MIN.) = 2.864 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.850 " NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE. SUBAREA RUNOFF(CFS) = 0.26 " TOTAL AREA(ACRES) = 0.05 TOTAL RUNOFF(CFS) = 0.26 **************************************************************************** FLOW PROCESS FROM NODE 2.00 TO NODE 3.00 IS CODE = 51m B >»»COMPUTE TRAPEZOIDAL CHANNEL FLOW<«« >»»TRAVELTIME THRU SUBAREA (EXISTING ELEMENT) <«« ELEVATION DATA: UPSTREAM(FEET) = 34.00 DOWNSTREAM(FEET) = 10.30 • CHANNEL LENGTH THRU SUBAREA(FEET) = 720.00 CHANNEL SLOPE = 0.0329 CHANNEL BASE(FEET) = 2.00 "Z" FACTOR = 2.000 . MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.850 • NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE. RESIDENTAIL (43. DU/AC OR LESS) RUNOFF COEFFICIENT = .7600 . SOIL CLASSIFICATION IS "A" S.C.S. CURVE NUMBER (AMC II) = 86 " TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 8.54 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 7.82 • AVERAGE FLOW DEPTH(FEET) = 0.39 TRAVEL TIME(MIN.) = 1.53 Tc(MIN.) = 4.40 1 SUBAREA AREA(ACRES) = 3.18 SUBAREA RUNOFF(CFS) = 16.56 AREA-AVERAGE RUNOFF COEFFICIENT = 0.760 ' TOTAL AREA(ACRES) = 3.23 PEAK FLOW RATE(CFS) = 16.82 " END OF SUBAREA CHANNEL FLOW HYDRAULICS: DEPTH(FEET) = 0.56 FLOW VELOCITY(FEET/SEC.) = 9.58 " LONGEST FLOWPATH FROM NODE 1.00 TO NODE 3.00 = 790.00 FEET. END OF STUDY SUMMARY: TOTAL AREA(ACRES) = 3.23 TC(MIN.) = 4.40 PEAK FLOW RATE(CFS) = 16.82 , END OF RATIONAL METHOD ANALYSIS II. CALCULATIONS B. DEVELOPED 100-YEAR STORM HYDROLOGY RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 2003,1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-2003 Advanced Engineering Software (aes) Ver. 1.5A Release Date: 01/01/2003 License ID 1459 Analysis prepared by: bHA, Inc. 5115 Avenida Encinas, Suite L Carlsbad, Calif 92008 FILE NAME: K:\HYDRO\o978\i.DATDDDnnnnnDnDDnnDDDnnnnnnnDDDDnnn TIME/DATE OF STUDY: 10:02 05/10/2005 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: 2003 SAN DIEGO MANUAL CRITERIA „ USER SPECIFIED STORM EVENT(YEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 2.600 m SPECIFIED MINIMUM PIPE SIZE(INCH) = 8.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE =0.90 - 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 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150 iW 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.* wn I .,. _1_J_-1_1J11M.___, -,„_,_„__„ mi.m_._-__..TT-1_____.rrJ_^J_^_,_ __ , __ra-re-^__Jir.-r-i - — _j_ .-11. • -• —. u. 1.1. • • — — ^m-—-— — — I..-I. mrr._L •I OCEAN STREET CONDOMINIUM I | DEVELOPED 100-YEAR HYDROLOGY I -! DEVELOPED BASIN 1 I + + • - FLOW PROCESS FROM NODE 1.00 TO NODE 2.00 IS CODE = 21 " >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« RESIDENTAIL (43. DU/AC OR LESS) RUNOFF COEFFICIENT = .7600 SOIL CLASSIFICATION IS "A" S.C.S. CURVE NUMBER (AMC II) = 86 . INITIAL SUBAREA FLOW-LENGTH (FEET) = 80.00 UPSTREAM ELEVATION (FEET) = 44.00 i DOWNSTREAM ELEVATION ( FEET) = 42.00 ELEVATION DIFFERENCE (FEET) = 2.00 m SUBAREA OVERLAND TIME OF FLOW(MIN.) = 4.033 100 YEAR RAINFALL INTENSITY (INCH/HOUR) = 6.850 1 NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE. SUBAREA RUNOFF (CFS) = 0.52 TOTAL AREA (ACRES) = ' 0.10 TOTAL RUNOFF (CFS) = 0.52 •* *************************************************************************** FLOW PROCESS FROM NODE 2.00 TO NODE 4.00 IS CODE = 41 >»»COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<«« >»»USING USER-SPECIFIED PIPESIZE (EXISTING ELEMENT) <«« ELEVATION DATA: UPSTREAM (FEET) = 42.00 DOWNSTREAM (FEET) = 18.70 FLOW LENGTH (FEET) = 95.00 MANNING'S N = 0.013 DEPTH OF FLOW IN 6.0 INCH PIPE IS 1.8 INCHES PIPE-FLOW VELOCITY (FEET/SEC. ) = 10.42 GIVEN PIPE DIAMETER (INCH) = 6.00 NUMBER OF PIPES = 1 PIPE-FLOW (CFS) = 0.52 PIPE TRAVEL TIME(MIN.) = 0.15 TcfMIN.) = 4.19 LONGEST FLOWPATH FROM NODE 1.00 TO NODE 4.00 = 175.00 FEET. ***************** FLOW PROCESS FROM NODE 4.00 TO NODE 4.00 IS CODE = 81 >»»ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<«« 100 YEAR RAINFALL INTENSITY ( INCH/HOUR) = 6.850 NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE. RESIDENTAIL (43. DU/AC OR LESS) RUNOFF COEFFICIENT = .7600 " SOIL CLASSIFICATION IS "A" S.C.S. CURVE NUMBER (AMC II) = 86 " AREA-AVERAGE RUNOFF COEFFICIENT = 0.7600 SUBAREA AREA(ACRES) = 0.78 SUBAREA RUNOFF(CFS) = 4.06 TOTAL AREA(ACRES) = 0.88 TOTAL RUNOFF(CFS) = 4.58 TC(MIN.) = 4.19 FLOW PROCESS FROM NODE 4.00 TO NODE 5.00 IS CODE = 41 " >»»COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<«« >»»USING USER-SPECIFIED PIPESIZE (EXISTING ELEMENT) <«« ELEVATION DATA: UPSTREAM ( FEET) = 18.70 DOWNSTREAM (FEET) = 13.30 FLOW LENGTH (FEET) = 130.00 MANNING'S N = 0.013 • DEPTH OF FLOW IN 12.0 INCH PIPE IS 7.2 INCHES PIPE-FLOW VELOCITY (FEET/SEC. ) = 9.38 GIVEN PIPE DIAMETER (INCH) = 12.00 NUMBER OF PIPES = 1 PIPE-FLOW (CFS) = 4.58 PIPE TRAVEL TIME(MIN-) = 0.23 Tc(MIN.) = 4.42 LONGEST FLOWPATH FROM NODE 1.00 TO NODE 5.00 = 305.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 5.00 TO NODE 6.00 IS CODE = 51 >»»COMPUTE TRAPEZOIDAL CHANNEL FLOW<«« • »>»TRAVELTIME THRU SUBAREA (EXISTING ELEMENT) <«« • ELEVATION DATA: UPSTREAM(FEET) = 13.30 DOWNSTREAM(FEET) = 11.55 CHANNEL LENGTH THRU SUBAREA(FEET) = 130.00 CHANNEL SLOPE = 0.0135 • CHANNEL BASE(FEET) = 6.00 "Z" FACTOR = 10.000 MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 1.00 • CHANNEL FLOW THRU SUBAREA(CFS) = 4.58 FLOW VELOCITY(FEET/SEC.) = 2.01 FLOW DEPTH(FEET) = 0.26 " TRAVEL TIME(MIN.) = 1.08 Tc(MIN.) = 5.50 LONGEST FLOWPATH FROM NODE 1.00 TO NODE 6.00 = 435.00 FEET.• *******************************+************************•******************** ' FLOW PROCESS FROM NODE 6.00 TO NODE 6.00 IS CODE = 10 ' >»»MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 1 <«« <•********>************************************************************ *" FLOW PROCESS FROM NODE 10.00 TO NODE 11.00 IS CODE = 21 »>»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« RESIDENTAIL (43. DU/AC OR LESS) RUNOFF COEFFICIENT = .7600 <•. SOIL CLASSIFICATION IS "A" S.C.S. CURVE NUMBER (AMC II) = 86 — INITIAL SUBAREA FLOW-LENGTH(FEET) = 82.00 UPSTREAM ELEVATION(FEET) = 43.70 *• DOWNSTREAM ELEVATION(FEET) = 37.00 ELEVATION DIFFERENCE(FEET) = 6.70 — SUBAREA OVERLAND TIME OF FLOW(MIN-) = 2.752 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.850 *" NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE. SUBAREA RUNOFF(CFS) = 0.36 ""• TOTAL AREA (ACRES) = 0.07 TOTAL RUNOFF (CFS) = 0.36 IM***************************************************** FLOW PROCESS FROM NODE 11.00 TO NODE 12.00 IS CODE = 61 m >»»COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<«« >»» (STANDARD CURB SECTION USED)<«« m UPSTREAM ELEVATION(FEET) = 37.00 DOWNSTREAM ELEVATION(FEET) = 11.76 Mi STREET LENGTH(FEET) = 430.00 CURB HEIGHT(INCHES) = 6.0 STREET HALFWIDTH(FEET) = 12.00 DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 7.00 H" INSIDE STREET CROSSFALL(DECIMAL) = 0.020 OUTSIDE STREET CROSSFALL(DECIMAL) = 0.020 m . SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1 • STREET PARKWAY CROSSFALL(DECIMAL) = 0.020 Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150 "" Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200 **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.43 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW: STREET FLOW DEPTH (FEET) = 0.22 HALFSTREET FLOOD WIDTH (FEET) = 4.86 AVERAGE FLOW VELOCITY ( FEET/SEC .) = 4.04 PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.90 STREET FLOW TRAVEL TIME(MIN.) = 1.78 Tc(MIN.) = 4.53 100 YEAR RAINFALL INTENSITY (INCH/HOUR) = 6.850 NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE. RESIDENTAIL (43. DU/AC OR LESS) RUNOFF COEFFICIENT = .7600 SOIL CLASSIFICATION IS "A" S.C.S. CURVE NUMBER (AMC II) = 86 AREA-AVERAGE RUNOFF COEFFICIENT = 0.760 SUBAREA AREA (ACRES) = 0.41 SUBAREA RUNOFF (CFS) = 2.13 TOTAL AREA (ACRES) = 0.48 PEAK FLOW RATE (CFS) = 2.50 END OF SUBAREA STREET FLOW HYDRAULICS: DEPTH (FEET) =0.26 HALFSTREET FLOOD WIDTH (FEET) = 6.61 FLOW VELOCITY (FEET/SEC. ) = 4.50 DEPTH*VELOCITY (FT*FT/SEC. ) = 1.16 LONGEST FLOWPATH FROM NODE 10.00 TO NODE 12.00 = 512.00 FEET. FLOW PROCESS FROM NODE 12.00 TO NODE 6.00 IS CODE = 41 „ >»»COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<«« >»»USING USER-SPECIFIED PIPESIZE (EXISTING ELEMENT) <«« ELEVATION DATA: UPSTREAM (FEET) = 11.76 DOWNSTREAM (FEET) = 11.55 . FLOW LENGTH (FEET) = 15.00 MANNING'S N = 0.013 DEPTH OF FLOW IN 12.0 INCH PIPE IS 6.9 INCHES • PIPE-FLOW VELOCITY (FEET/SEC. ) = 5.38 GIVEN PIPE DIAMETER (INCH) = 12.00 NUMBER OF PIPES = 1 • PIPE-FLOW (CFS) = 2.50 PIPE TRAVEL TIME (WIN.) = 0.05 Tc(MIN.) = 4.57 1 LONGEST FLOWPATH FROM NODE 10.00 TO NODE 6.00 = 527.00 FEET. ***************************************************************************** FLOW PROCESS FROM NODE 6.00 TO NODE 6.00 IS CODE = 11 >»»CONFLUENCE MEMORY BANK # 1 WITH THE MAIN-STREAM MEMORY<««_ __ ____ ___ __ ____ ** MAIN STREAM CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 2.50 4.57 6.850 0.48 LONGEST FLOWPATH FROM NODE 10.00 TO NODE 6.00 ** MEMORY BANK # 1 CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 4.58 5.50 6.445 0.88 LONGEST FLOWPATH FROM NODE 1.00 TO NODE 6.00 ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) 527.00 FEET. 435.00 FEET. 1 6.31 4.57 6.850 2 6.93 5.50 6.445 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 6.93 Tc(MIN.) = 5.50 TOTAL AREA (ACRES) = 1.36 FLOW PROCESS FROM NODE 6.00 TO NODE 6.00 IS CODE = 12 __ ___- — — -—_____ — ,-._ _____ _ _ _ _ _ _~™ ~~ " ~™ ~* ~~ >»»CLEAR MEMORY BANK I 1 <«« fURI* ******************************************* ^ FLOW PROCESS FROM NODE 6.00 TO NODE 7.00 IS CODE = 51 >»»COMPUTE TRAPEZOIDAL CHANNEL FLOW<«« *" »>»TRAVELTIME THRU SUBAREA (EXISTING ELEMENT) <«« ELEVATION DATA: UPSTREAM (FEET) = 11.55 DOWNSTREAM (FEET) = 10.65 „„ CHANNEL LENGTH THRU SUBAREA ( FEET) = 160.00 CHANNEL SLOPE = 0.0056 CHANNEL BASE (FEET) = 6.00 "Z" FACTOR = 10.000 ta MANNING'S FACTOR = 0.030 MAXIMUM DEPTH (FEET) = 1.00 CHANNEL FLOW THRU SUBAREA(CFS) = 6.93 „„, FLOW VELOCITY (FEET/SEC. ) = 1.65 FLOW DEPTH (FEET) = 0.41 TRAVEL TIME (MIN.) = 1.62 Tc(MIN.) = 7.12 m LONGEST FLOWPATH FROM NODE 10.00 TO NODE 7.00 = 687.00 FEET. itm **************************************************************************** FLOW PROCESS FROM NODE 7.00 TO NODE 7.00 IS CODE = 10m ____________________________________________________________________________ >»»MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 1 <«« ******************************************************************************* FLOW PROCESS FROM NODE 21.00 TO NODE 22.00 IS CODE = 21 ta >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« RESIDENTAIL (43. DU/AC OR LESS) RUNOFF COEFFICIENT = .7600 "" SOIL CLASSIFICATION IS "A" „, S.C.S. CURVE NUMBER (AMC II) = 86 INITIAL SUBAREA FLOW-LENGTH ( FEET) = 60.00 ^ UPSTREAM ELEVATION (FEET) = 45.00 DOWNSTREAM ELEVATION ( FEET) = 43.00 ta ELEVATION DIFFERENCE ( FEET) = 2.00 SUBAREA OVERLAND TIME OF FLOW(MIN.) = 3.174 „ 100 YEAR RAINFALL INTENSITY (INCH/HOUR) = 6.850 NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE. «» SUBAREA RUNOFF (CFS) = 0.52 TOTAL AREA(ACRES) = 0.10 TOTAL RUNOFF(CFS) = 0.52 mm **************************************************************************** •" FLOW PROCESS FROM NODE 22.00 TO NODE 22.00 IS CODE = 81 "" »»>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<«« 100 YEAR RAINFALL INTENSITY ( INCH/HOUR) = 6.850 „, NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE. RESIDENTAIL (43. DU/AC OR LESS) RUNOFF COEFFICIENT = .7600 * SOIL CLASSIFICATION IS "A" S.C.S. CURVE NUMBER (AMC II) = 86 * AREA-AVERAGE RUNOFF COEFFICIENT = 0.7600 SUBAREA AREA (ACRES) = 1.30 SUBAREA RUNOFF (CFS) = 6.77 * TOTAL AREA (ACRES) = 1.40 TOTAL RUNOFF (CFS) = 7.29 TC(MIN.) = 3.17 • **************************************************************************** * FLOW PROCESS FROM NODE 22.00 TO NODE 23.00 IS CODE = 41 * >»»COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<«« a >»»USING USER-SPECIFIED PIPESIZE (EXISTING ELEMENT) <«« ELEVATION DATA: UPSTREAM (FEET) = 43.00 DOWNSTREAM (FEET) = 18.70 " FLOW LENGTH (FEET) = 330.00 MANNING'S N = 0.013 m DEPTH OF FLOW IN 12.0 INCH PIPE IS 8.1 INCHES PIPE-FLOW VELOCITY (FEET/SEC. ) = 12.96 GIVEN PIPE DIAMETER (INCH) = 12.00 NUMBER OF PIPES = 1 PIPE-FLOW (CFS) = 7.29 „ PIPE TRAVEL TIME(MIN-) = 0.42 Tc(MIN.) = 3.60 LONGEST FLOWPATH FROM NODE 21.00 TO NODE 23.00 = 390.00 FEET. • FLOW PROCESS FROM NODE 23.00 TO NODE 7.00 IS CODE = 41 . »>»COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<«« >»»USING USER-SPECIFIED PIPESIZE (EXISTING ELEMENT) <«« ELEVATION DATA: UPSTREAM (FEET) = 18.70 DOWNSTREAM (FEET) = 10.65 " FLOW LENGTH(FEET) = 75.00 MANNING'S N = 0.013 DEPTH OF FLOW IN 12.0 INCH PIPE IS 7.1 INCHES " PIPE-FLOW VELOCITY (FEET/SEC. ) = 15.05 GIVEN PIPE DIAMETER (INCH) = 12.00 NUMBER OF PIPES = 1 " PIPE-FLOW (CFS) = 7.29 PIPE TRAVEL TIME (MIN.) = 0.08 Tc(MIN.) = 3.68 " LONGEST FLOWPATH FROM NODE 21.00 TO NODE 7.00 = 465.00 FEET. ***************************************************************************** , FLOW PROCESS FROM NODE 7.00 TO NODE 7.00 IS CODE = 11 . >»»CONFLUENCE MEMORY BANK I 1 WITH THE MAIN-STREAM MEMORY<«« i ** MAIN STREAM CONFLUENCE DATA ** , STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) • 1 7.29 3.68 6.850 1.40 LONGEST FLOWPATH FROM NODE 21.00 TO NODE 7.00 = 465.00 FEET. i ** MEMORY BANK # 1 CONFLUENCE DATA ** ' STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) ' 1 6.93 7.12 5.456 1.36 LONGEST FLOWPATH FROM NODE 10.00 TO NODE 7.00 = 687.00 FEET. m ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY • NUMBER (CFS) (MIN.) (INCH/HOUR) 1 10.88 3.68 6.850 m 2 12.74 7.12 5.456 • COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 12.74 Tc(MIN.) = 7.12 • TOTAL AREA(ACRES) = 2.76 ™****************************************** FLOW PROCESS FROM NODE 7.00 TO NODE 7.00 IS CODE = 12•i m >»»CLEAR MEMORY BANK # 1 <«« === ==3=== —====== — :======:====== ===:==== = = = :=====:=:=:==:=============:=======:=::======:== ***************************************************************************** „ FLOW PROCESS FROM NODE 7.00 TO NODE 3.00 IS CODE = 51 ^ >»»COMPUTE TRAPEZOIDAL CHANNEL FLOW<«« >»»TRAVELTIME THRU SUBAREA (EXISTING ELEMENT) <«« ELEVATION DATA: UPSTREAM(FEET) = 10.65 DOWNSTREAM(FEET) = 10.30 „ CHANNEL LENGTH THRU SUBAREA(FEET) = 130.00 CHANNEL SLOPE = 0.0027 CHANNEL BASE(FEET) = 6.00 "Z" FACTOR = 10.000 • MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 1.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.845 . RESIDENTAIL (43. DU/AC OR LESS) RUNOFF COEFFICIENT = .7600 SOIL CLASSIFICATION IS "A" " S.C.S. CURVE NUMBER (AMC II) = 86 TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 13.60 • TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.50 AVERAGE FLOW DEPTH(FEET) = 0.70 TRAVEL TIME(MIN.) = 1.44 " Tc(MIN.) = 8.56 SUBAREA AREA(ACRES) = 0.47 SUBAREA RUNOFF(CFS) = 1.73 " AREA-AVERAGE RUNOFF COEFFICIENT = 0.760 TOTAL AREA(ACRES) = 3.23 PEAK FLOW RATE(CFS) = 12.74 END OF SUBAREA CHANNEL FLOW HYDRAULICS: " DEPTH(FEET) = 0.67 FLOW VELOCITY(FEET/SEC.) = 1.48 . LONGEST FLOWPATH FROM NODE 10.00 TO NODE 3.00 = 817.00 FEET. . END OF STUDY SUMMARY: TOTAL AREA(ACRES) = 3.23 TC(MIN.) = 8.56 I PEAK FLOW RATE(CFS) = 12.74 END OF RATIONAL METHOD ANALYSIS III. EXHIBITS III. EXHIBITS A. EXISTING HYDROLOGY MAP III. EXHIBITS A. DEVELOPED HYDROLOGY MAP PI M IV. REFERENCES I Ml tU? ^\ 'V^%^^ H * sis! ^*tD - j j I V I C. "7~~ // / 4 1 > From precipitation maps determine 6 hr and 24 hr amountsfor the selected frequency. These maps are included in theCounty Hydrology Manual (10, 50, and 100 yr rnaps includedin the Design and Procedure Manual).— X4 / /- i f f i / J iEQUATION'— j f Vr / 7/•ange ol 45% lo 65% ol the 24 hr precipitation (noticaple to Desert).6 hr precipitation on the right side of the chart.rilil t S 5 ¥•J3 i 1 1T C CD = 7.44 P6D= Intensity (= 6-Hour Pr_ . yy ' f~f //f f /r — / -IL ".'''.'.'~:~~~. •- 7~T" / / 4/ 7 y / //// /"/ t //= Duration (min)Cl •==zf. •=} yyy f / ->"/— -- L. f / f / •f / / / / - J /(5) This line is the intensity-duration curve for the locationbeing analyzed."f:"~ji "/"] /'—i ^L —~t- /y T ? / / fcjt / / JOT: T /*/ .y/f Application Form:[a) Selected freouencv /0& vear64 / / j / *f '//<* / r // y ... .y. y y / / / f ^n 4 I & SL ,£ rvi VO n S" T3 1 ' I"u" c '£ > n .i u "w1 -lour Precipitation (Inohes O >O O **5 O Uti / y f J / J r /r / ,//£//f f f r/ f f / ^=== f f y — yf / / / b U? -y i- / »J / £=, 2 -y 1 "; y ^-y j ^/ ^* /••• ^ •vl _/ / ^ ^ ^7 / •^ — V' i f y ' ./Note: This chart replaces the lnteristb/-Duration*Frequencyo c f /// i f f •=:::/. f ii i )) -j tr"> & -y- f '"fr / in — ^_ a D ij JS IX t*J I*';, f) flft It) Hi (M Ul fN t\i V O> <V) (M "*f "OJ'"OlT"*lQ(sCVOTWCQtOV'''~ O 0^ ,**i«*.»rf4. , * *. ^ * •*• t i— mWOJOlP'vtflliftCOlfJ'O'piNf* CJ ^ •0" ^;2®tO'i*'**^WWW<^*-'^-^--r-OO 5? W «> OT Tf W <»J W W:W w";*-.^- :*-:<J;<^ _» in •"t-icn r«jwi-*-*-*-»-ooOrtr>Ort j ^ ^ o y <NJ r (/ , J . J /• / t—^i "™"™"..™ !! ! " '.,' " !8SS?S§80||||| •) r • ? i ±=P= r * . -" ". '. ' = E5E| qi~ -- .... _ ...'"" .... f ::-r{":"r =1= ! o ^ o o o o w c? o o <* « N w «} «r, <*( I'M *"a* o> «6 *.' <o ui ir '•> cO i^odcidoci o o e" (jnoq/ssqaui) jtysuayui 5 erO r: -8 .0 10 i CO ign Chart - TemplateDuratioens §< i H| « \ pi \ ji Issl ill II u co i Imperial County « CM SI. .OE./U .OE.2U •a3 K d! I it j ti tu n, Imperial County ,SU9H ,0€.9H o <^ <* **> m a <> V7'<J> M -*' * O •2- ^> O O V -=> o c* o &~t- ~f *x •• * ^^ill M JPI * m^;m ^©\ ^\ '• x^.*^1 ^^ \ W 1 660000 FE£T R. 5 W. | R. 4 W. m m m m m m rABLb • 15 INTERPRETATIONS FOR LAND MANAGEMENT KEY TO INTERPRETATION RATING SYMBOLS: (3/4) HYDROLOGIC SOIL GROUPS: LIMITATIONS: A • HIGH INFILTRATION RATE SL - SLIGHT DECREE OF LIMITATION B • MODERATE INFILTRATION RATE M - MODERATE DEGREE OF LIMITATION C • SLOW INFILTRATION BATE SE - SEVERE DECREE OF LIMITATION D • VER Y SLOW INFIL TRA TlON RA TE Soil Map Symbol3 (1) InA InB loA IsA KcC KcD2 LaE2 LaE3 LcE LcE2 LcF2 LdE ° (La) (Sp) LdG c (La) (Sp) LeC LeC2 LeD LeD2 LeE LeE2 LeE3 LfC c (Le) (Ur) LfE c (Le) (Ur) LpB LpC LpC2 LpD2 LpE2 LrE LrE2 LrG LsE LsF Interpretation Rating6 HydrologicGroup(2) C C C C B B A A A A A A C A C D D D D D D D D D D D D D D D D D D D C C Erodibility by Water (3) SE (str) SE (str) SE (str) SE (str) SE (txt) SE (txt) SE (txt) SE (txt) SE (txt) SE (txt) SE (sip) SE (txt) SE (txt) SE (sip) SE (sip) SE (txt) SE (txt) SE (txt) SE (txt) SE (txt) SE (txt) SE (txt) M (txt) M (txt) M (txt) M (txt) M (sip) M (sip) M (sip) SE (sip) M (txt) SE (sip) = •5° =£<5s g Eo 5iS (4) SL 9 SL K SL 9 SE 9 • M 9 M 9 M 5 M a M 9 M » M a SL SL SL SL SL SL SE SL SL SL SL SL M M M M M Soil Map Symbol3 (1) Lu LvF3 c (Lu) (Hr) JVld - MIC MIE MnA MnB MoA MpA2 MrG MvA MvC MvD MxA OhC OhE OhF OkC c (Oh) (Ur) OkE c (Oh) (Ur) PeA PeC PeC2 PeD2 PfA PfC PV RaA RaB RaC RaC2 RaD2 RcD Interpretation Rating6 .H'5>o 0 0.*1I C3 (2) B D D D A A B B B B D A A A D D D D D D D D D D D D D D D C C C C C C Erodibility by Water (3) SE (str) SE (sip) SE (sip) SE (txt) ^ SE (txt) SE (str) SE (str) SE (str) SE (str) SE (sip) SE (txt) SE (txt) SE (txt) SE (txt) SE (str) SE (str) SE (sip) SE (dpt) SE (dpt) SE (dpt) SE (dpt) SE (str) SE (str) M (txt) SE (str) SE (str) SE (str) SE (str) SE (str) SE (str) .11££ls § EcS cSS2 (4) SL SE SE SL SL SE SL B SL s SL a SL a SL SL M SL SL SL SL SL SL SL SL SL SL SL SL 95 • •• HI m m pi M IMl m IMl DM «• •ri §•1IPP M |M •1 NPi HI nm * M m m \o f<1 CN 0 .2 •• 0 00u aC/3 P-< "33Cca &O s San Diego County Hy<Date: June 2003CO< < ^-j^5 p& ^ta f> CO^> H3z £Suh>4gw u pT-j toOz 0* b TS•2-'us oU tooc3 U</3 P T3C J3 u1 'oCO Q u ffl piW PH 5 1 1w g oU CiQ'e 1 00U I/") i— V£) ON, fN) f^- O <"*") *— • C?N ON CN '•O *^ ^ro ^ *?}• ^f 10 "o \D *O t — r*~ t~* oo oo oo oo ooooooooooooooo o^ocNtooo^-c-oaNOooo^^-^-t-r^> co ^" T}~ Tj1 v~t »/^ \o ^o r*~ t^~ oo oo oo ooooooooooooooooo Sqpjg^^^^g^pr^g^Sooo ooooooooooooooo Sr5?i^:?^v:ii/-)'of2r2ooooooooooooooooooooooo * ooi/ioomomooviooi/i "rtvi vi vi in •« ouuuu — — — • — — . <u uuu.uuOOOO'3 g ca ^ ^ ^ ^ ^ ^—N i^ — ; ^ — • T^r fl rj ^•DDDDDQQQQ E-2-^^gQQPQQ^^j.j,..,,^ ^ g!«!2 'c^2!s5!2!2!2^2."23-£u °£ e |^^^^^^^^^^ 2 g a §C 'w 'w "w '« 'w 'w 'w 'w '« -2r C y^ g C OnPiPiPiPHPHDHKO-PiZOOl— IO ^g c?S'£'p? ^_x^v^, lD?c?S-§i,i,i,2>2>^'e>| 13 1 £,DQo!r'^'i'iirQQt2(2 . •? g ••*; k—J t— J i-J .2 -2 'S -2 si^ ?^j ^ f ^^ £3 ^ ^ c e c '« '« '55 '« g g .2 .2 .2 .2 .2 •o^^^g g g g^-^SSSSS ^ '? '5 '2 Q Q Q Q e e '3 "o '3 'o '3iiiiiiiiss|iiiiiiiiiiiif t lass s C cd2 <o^5 3 r •g ^ « ^ •5 g .5 *nj c §g S« 28 c ^i fi-t—i ,f*S "•- c * O cct O rrt 00 ^g C *^ "S 5 r« c 0 ^ •rt 8^-^ CiOC 3CJ c '3 53 .2 §| 1| 0 f^*£* .« "*^ 3 ^ & O w 5 E »— H d>s-eUU- *Q "^ 3 •2-1~o g §1 ^* "trt *J E ^C '> W ^ ^0 g C*C 03 OC ' '"" .§00 g ^^ P« S tn CJ jG -&.O « w I'M ~— *-• L_ ^ * g 1 8. 1HZ] ., _ _ r/v O *The values associatecoefficient, Cp, for theis located in ClevelandDU/A = dwelling unit:NRCS = National Resi m m m m m San Diego County Hydrology Manual Date: June 2003 Section: Page: 3 12 of 26 Note that the Initial Time of Concentration should be reflective of the general land-use at the upstream end of a drainage basin. A single lot with an area of two or less acres does not have a significant effect where the drainage basin area is 20 to 600 acres. Table 3-2 provides limits of the length (Maximum Length (LM)) of sheet flow to be used in hydrology studies. Initial Tj values based on average C values for the Land Use Element are also included. These values can be used in planning and design applications as described below. Exceptions may be approved by the "Regulating Agency" when submitted with a detailed study. Table 3-2 MAXIMUM OVERLAND FLOW LENGTH (LM) & INITIAL TIME OF CONCENTRATION (TQ Element* Natural LDR LDR LDR MDR MDR MDR MDR HDR HDR N. Com G. Com O.P./Com Limited I. General I. DU/ Acre 1 2 2.9 4.3 7.3 10.9 14.5 24 43 .5% LM 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 T; 13.2 12.2 11.3 10.7 10.2. 9.2 8.7 8.2 6.7 5.3 5.3 4.7 4.2 4.2 3.7 1% LM 70 70 70 70 70 65 65 65 65 65 60 60 60 60 60 Ti 12.5 11.5 10.5 10.0 9.6 8.4 7.9 7.4 6.1 4.7 4.5 4.1 3.7 3.7 3.2 2% LM 85 85 85 85 80 80 80 80 75 75 75 75 70 70 70 Ti 10.9 10.0 9.2 8.8 8.1 7.4 6.9 6.5 5.1 4.0 4.0 3.6 3.1 3.1 2.7 3% LM 100 100 100 95 95 95 90 90 90 85 85 85 80 80 80 Ti 10.3 9.5 8.8 8.1 7.8 7.0 6.4 6.0 4.9 3.8 3.8 3.4 2.9 2.9 2.6 5% LM 100 100 100 100 100 100 100 100 95 95 95 90 90 90 90 Ti 8.7 8.0 7.4 7.0 6.7 6.0 5.7 5.4 4.3 3.4 3.4 2.9 2.6 2.6 2.3 10% LM 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 Ti 6.9 6.4 5.8 5.6 5.3 4.8 4.5 4.3 3.5 2.7 2.7 2.4 2.2 2.2 1.9 *See Table 3-1 for more detailed description 3-12 EQUATION A E _ /11.9L3Y>.385 Feet TC ' V AE 7 5000 Tc = Time of concentration (hours) L a Watercourse Distance (miles) — 4000 ^g _ change in elevation along effective slope line (See Figure 3-5) (feet) 3000 Tc Hours 2000 4 3 1000 - 900 ^ 800 * -WJ -600\ 500 \\ 400 \ •^> 1 300 ^> \ \ 200 \ - \ — V L,\ Miles Feet \— 100 1^n^.*• — "" HB *"* f\ <— 50 U-3 w — 40 _. — 30 — 20 — 10 5 Z-4000N - \ — 3000 \ \ 2000 \ — 1800 \ — 1600 \ — 1400 \ — 1200 1000 — 900 — 800 — 700 — 600 — 500 — 400 — 300 - — 200 Minutes — 240 — 180 120 — 100 —90 — 80 — 70 60 50 — 40 — 30 """""" *" — 18 — 16 — 14 — 12 10 — 9 — 8 — 7 — 6 — 5 — 4 — 3 AE L Tc SOURCE: California Division of Highways (1941) and Kirpich (1940) FIGURE Nomograph for Determination of Time of Concentration (Tc) or Travel Time (Tt) for Natural Watersheds 3-4 Watershed Divide Watershed Divide. Area "A" = Area "B" SOURCE: California Division of Highways (1941) and Kirpich (1940) Design Point (Watershed Outlet) PI m FIGURE Computation of Effective Slope for Natural Watersheds 3-5 0.4 5 6 7 8 9 10 Discharge (C.F.S.) EXAMPLE: Given: Q = 10 S = 2.5% Chart gives: Depth = 0.4, Velocity = 4.4 f.p.s. SOURCE: San Diego County Department of Special District Services Design Manual 30 40 50 FIGURE Gutter and Roadway Discharge • Velocity Chart 3-6 EQUATION: V = 1.49 R^ s1"n •P "o,0 l_ 05Q. 0> £ C UJQ.3 CO c-0.3 Lo.2 -0.15 : -0.10 •0.09 •0.08 -0.07 •0.06 •0.05 -0.04 - 0.03 • - 0.02 ^ •S>£ C CO - 0.01 D - 0.009 ^ 0.008 Q 0.007 3 0.006 < 0.005 Q >- - O.OO^^X ^s* *O003 • 0.002 0.001 0.0009 0.0008 0.0007 0.0006 0.0005 0.0004 0.0003 j-0.2 - .0.3 . .0.4 -0.5 .0.6 .^K .0.8 \ \ ' 1'° \?<? \N \ " 2 e. ^^"^ '.^ - 4 -6 - 7 • 8 •9 - 10 p.50 f-40 \ jf» \ ^ "-x 8 .X^ <u•^ w <" »\ ^ \ 0 UJ> . 20 -30 * -20 . JX" 1.^ •^^•"9 c•8 , • 7 S*o fi E-6 g O r5 COCOUJ2-4 I; ° occ -2 • r-1.0 .0.9 i-0.8 j.0.7 •0.6 -0.5 -0.01 -0.02 -0.03 -0.04 -0.05 .0.06 -0.07 -0.08 • 0.09 -0.10 -0.2 . -0.3 -0.4 GENERAL SOLUTION SOURCE: USDOT, FHWA, HDS-3 (1961) FIGURE Manning's Equation Nomograph 3-7