The URL can be used to link to this page

Home My WebLink About3674; Poinsettia Lane Dejong Property; Poinsettia Lane Dejong Property; 1999-03-25HUN SAKE R &ASSOCIATES SAN DIEGO, INC. PLANNING ENGINEERING SURVEYING IRVINE LAS VEGAS RIVERSIDE SAN DIEGO HYDROLOGY STUDY for POINSETTIA LANE (DEJONG PROPERTY) in the City of Carlsbad Prepared for: City of Carlsbad 2075 Las Palmas Drive Carlsbad, CA 92008 W.O. 2322-1 March 25, 1999 Revised June 18, 1999 DAX'E HAMMAR IACK HILL LEX VVILLIMAN 10171 Huwinpkens St. Suite 200 S.in Diq;o, CA '12121 (619)558-4500 PH (619)558-1414 FX www.lujnsaker.rom lnto@HunsakerSD.com Hunsaker & Associates San Diego, Inc. Raymond L. Martin, R.C.E. Project Manager DB:kd msword\kA2322U999\a05.doc wo 2322-1 06/30/99 Poinsettia Lane Hydrology Study TABLE OF CONTENTS References Introduction Existing Conditions Proposed Development Conclusions Vicinity Map Criteria and Methodology 100-year Hydrology Study Hydraulics Curb Inlet Sizing Rip Rap Energy Dissipator Headwall Calculation Reference Data Hydrology Map SECTION I I IV V V V VI (pocket) OB:kd msword\k:\2322\1999\a05.doc wo 2322-1 07/01/99 Poinsettia Lane Hydrology Study References Introduction Existing Conditions 1) Standards for Design and Construction of Public Works Improvements in the City of Carlsbad, 1993 2) The County of San Diego Drainage Design & Procedure Manual 3) Hydrology Study for Aviara Phase III CT 85-35 in the City of Carlsbad, Revised April 2, 1996 4) Hydrology Study for DeJong Property in the City of Carlsbad, Revised July 30, 1998 This hydrology report was prepared in conjunction with the submittal of grading and improvement plans for Poinsettia Lane within the City of Carlsbad. This report includes: • Hydrology calculations to determine the 100-year peak discharge from the proposed site. • Inlet calculations to determine the type and size of inlets needed to intercept 100% of the 100-year peak discharge developed within Poinsettia Lane. • Preliminary pipe sizing for the proposed storm drainage system. The proposed construction of Poinsettia Lane is located on the southerly boundary of the DeJong property within Local Facilities Management Plan Zone 20 in the City of Carlsbad. This construction will link the two existing portions of Poinsettia Lane for an approximate length of 1,350 feet. Black Rail Road is located directly west of the proposed construction site. This existing road conveys drainage from the south 0.6 acres. This drainage will then flow easterly over Poinsettia Lane to a storm drain system. Undeveloped property, south of the proposed site contributes to a tributary area of approximately 10.9 acres. Proposed Development This project proposes construction of Poinsettia Lane, a 102-foot major arterial. Runoff from south of the road will be intercepted by a brow ditch running along the toe of slope and conveyed to the storm drain system crossing Poinsettia. The DeJong Property, north of the road, proposes development of 20 single family homes. This subdivision is to have a portion of its drainage collected and conveyed through the proposed storm drain system. This storm drain system discharges to an existing, northeasterly trending canyon. The flows from the subdivision used in this study were obtained from the "Hydrology Study for DeJong Property" (see Reference No. 4). A portion of this study has been included in Section VI for easy reference. DB:kd msword\k:\2322\1999\a01.doc wo 2322-1 06/15/99 Poinsettia Lane Hydrology Study East of the site is existing Aviara Phase 3. The hydrology report approved with Aviara Phase 3 assumed accepting drainage from approximately 160 feet of the most eastern portion of proposed Poinsettia Lane, therefore this study does not include that portion of road. For reference, the drainage map from the Aviara report "Hydraulic Study for Aviara Phase III" (see Reference No. 3), has been included in Section VI. The DeJong Tentative Map proposes a series of check dams to mitigate potential adverse impacts due to concentration of drainage from that subdivision. This project stubs an 18-inch pipe for use by the subdivision, but the culvert will remain empty until the time of development. Therefore, analysis of the check dam system is deferred. The drainage report of the DeJong project should include this work in the future. Preliminary hydraulics indicate a velocity of 38 ft./sec. May be attained in the 24-inch RCP outfall to the canyon. During final design, this velocity will need to be mitigated. We will propose velocity control rings to reduce the outletting velocity to below 20 ft./sec. This will allow use of a D-40 energy dissipator at the outlet. Conclusion A 24-inch culvert is recommended to convey drainage within the project. Curb inlets have been sized and are being constructed to collect drainage from the road. DB:kd msword\k:\2322\1999\a01.doc wo 2322-1 06/15/99 Poinsettia Lane Hydrology Study VICINITY MAP NO SCALE FIGURE 1 VICINITY MAP POINSETTIA LANE DB:kd m«ronft\y>csanw\coiretpndnc\2322M 999\i01.doc wo 2322-1 03/18/99 Poinsettia Lane Hydrology Study Drainage Criteria and Methodology Design Storm 100-year storm Land Use Single-family, per General Plan Map Soil Type A hydrologic soil group "D" was consistently used for this entire study. Runoff Coefficient "C" values were based on the County of San Diego Drainage Design & Policy Manual. The site is single-family residential, therefore a "C" value of 0.55 was used for these areas. Where subareas are composed almost entirely of street, a "C" value of 0.95 was used. Rainfall Intensity The rainfall intensity values were based on the criteria presented in the County of San Diego Drainage Design & Policy Manual. DB:kd msword\k:\2322M 999\a01.doc wo 2322-1 06/15/99 Poinsettia Lane Hydrology Study HYDROLOGY METHOD OF ANALYSIS The computer generated analysis for this watershed is consistent with current engineering standards and requirements of the City of Carlsbad. This report also contains calculations for the proposed storm drain within the project limits. RATIONAL METHOD The most widely used hydrologic model for estimating watershed peak runoff rates is the rational method. The rational method is applied to small urban and semi-urban areas of less than 0.5 square miles. The rational method equation relates storm rainfall intensity, a selected 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 concentrations. A = The drainage basin area in acres. NODE-LINK STUDY In performing a node-link study, the surface area of the basin is divided into basic areas which discharge into different designated drainage basins. These "sub-basins" depend upon locations of inlets and ridge lines. SUBAREA SUMMATION MODEL The rational method modeling approach is widely used due to its simplicity of application, and its capability for estimating peak runoff rates throughout the interior of a study watershed analogous to the subarea model. 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 the subsequent subareas gradually increasing in size. Assign upstream and downstream nodal point numbers to each subarea in order to correlate calculations to the watershed map. (2) Estimate a Tc by using a nomograph or overlaid flow velocity estimation. DB:kd msword\k:\2322\1999\a01.doc wo 2322-1 06/15/99 Ill ************************************************* **» RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE * Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-93 Advanced Engineering Software (aes) Ver. 1.5A Release Date: 7/10/93 License ID 1239 ** Analysis prepared by: *"" HUNSAKER & ASSOCIATES Irvine, Inc. Planning * Engineering * Surveying Three Hughes * Irvine , California 92718 * (714) 538-1010 ************************** DESCRIPTION OF STUDY ************************** ,-,.* POINSETTIA LANE * * 100-YEAR HYDROLOGY STUDY * -* WO#2322-1 * ************************************************************************** , FILE NAME: H:\AES92\2322\1\100.RAT TIME/DATE OF STUDY: 12:23 3/25/1999 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:v-n» „ 1985 SAN DIEGO MANUAL CRITERIA - USER SPECIFIED STORM EVENT(YEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 2.600 ** 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 100.00 TO NODE 105.00 IS CODE = 21 »>»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 INITIAL SUBAREA FLOW-LENGTH = 450.00 UPSTREAM ELEVATION = 383.50 DOWNSTREAM ELEVATION = 363.92 ELEVATION DIFFERENCE = 19.58 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 12.865 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.724 SUBAREA RUNOFF(CFS) = 1.23 TOTAL AREA(ACRES) = .60 TOTAL RUNOFF(CFS) = 1.23 M» ******************************************************************: ^ FLOW PROCESS FROM NODE 105.00 TO NODE 110.00 IS CODE = 6 >»»COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA<«« UPSTREAM ELEVATION = 363.92 DOWNSTREAM ELEVATION = 318.08 . STREET LENGTH(FEET) = 1119.60 CURB HEIGHT(INCHES) = 6. STREET HALFWIDTH(FEET) = 42.00«• DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK = 21.00 INTERIOR STREET CROSSFALL(DECIMAL) = .020 - OUTSIDE STREET CROSSFALL(DECIMAL) = .020 "" SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1 **TRAVELTIME COMPUTED USING MEAN FLOW(CFS) = 3.25 STREETFLOW MODEL RESULTS: STREET FLOWDEPTH(FEET) = .29 HALFSTREET FLOODWIDTH(FEET) = 8.14 AVERAGE FLOW VELOCITY(FEET/SEC.) = 4.16 PRODUCT OF DEPTH&VELOCITY = 1.20 m STREETFLOW TRAVELTIME(MIN) = 4.49 TC(MIN) = 17.35 *» 100 YEAR RAINFALL INTENSITY (INCH/HOUR) = 3.070 - SOIL CLASSIFICATION IS "D" INDUSTRIAL DEVELOPMENT RUNOFF COEFFICIENT = .9500 „ SUBAREA AREA(ACRES) = 1.40 SUBAREA RUNOFF(CFS) = 4.08 SUMMED AREA(ACRES) = 2.00 TOTAL RUNOFF(CFS) = 5.31 * END OF SUBAREA STREETFLOW HYDRAULICS: DEPTH(FEET) = .33 HALFSTREET FLOODWIDTH(FEET) = 10.04 " FLOW VELOCITY(FEET/SEC.) = 4.71 DEPTH*VELOCITY = 1.54 •* ,!*•*************************************************************************** FLOW PROCESS FROM NODE 105.00 TO NODE 110.00 IS CODE = 1m »>»DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<«« «* TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: * TIME OF CONCENTRATION(MIN.) = 17.35 m RAINFALL INTENSITY(INCH/HR) = 3.07 TOTAL STREAM AREA(ACRES) = 2.00 .« PEAK FLOW RATE (CFS) AT CONFLUENCE = 5.31 «• ********************************************************************* FLOW PROCESS FROM NODE 115.00 TO NODE 120.00 IS CODE = 21. .j» >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 INITIAL SUBAREA FLOW-LENGTH = 400.00 UPSTREAM ELEVATION = 383.50 DOWNSTREAM ELEVATION = 350.00 ELEVATION DIFFERENCE = 33.50 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 9.751 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.453 SUBAREA RUNOFF(CFS) = 3.18 TOTAL AREA(ACRES) = 1.30 TOTAL RUNOFF(CFS) = 3.18 ****************************************************** ********************** ,„ FLOW PROCESS FROM NODE 120.00 TO NODE 125.00 IS CODE = 51 *" >»»COMPUTE TRAPEZOIDAL CHANNEL FLOW<«« >»»TRAVELTIME THRU SUBAREA<«« - UPSTREAM NODE ELEVATION =350.00 DOWNSTREAM NODE ELEVATION = 330.00 "- CHANNEL LENGTH THRU SUBAREA (FEET) = 330.00 ^ CHANNEL SLOPE = .0606 CHANNEL BASE(FEET) = 2.00 "Z" FACTOR = 2.000 -. MANNING'S FACTOR = .030 MAXIMUM DEPTH (FEET) = 2.00 CHANNEL FLOW THRU SUBAREA(CFS) = 3.18 *" FLOW VELOCITY (FEET/SEC) = 4.45 FLOW DEPTH (FEET) = .28 TRAVEL TIME(MIN.) = 1.24 TC(MIN.) = 10.99 •A* **************************************************************************** - FLOW PROCESS FROM NODE 120.00 TO NODE 125.00 IS CODE = 8 *"* >»»ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<«« 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.123 • SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 " SUBAREA AREA(ACRES) = 2.50 SUBAREA RUNOFF(CFS) = 5.67 . TOTAL AREA(ACRES) = 3.80 TOTAL RUNOFF(CFS) = 8.85 TC(MIN) = 10.99 f» '***************************************************************************** FLOW PROCESS FROM NODE 125.00 TO NODE 130.00 IS CODE = 51 • >»»COMPUTE TRAPEZOIDAL CHANNEL FLOW<«« »»>TRAVELTIME THRU SUBAREA<««• ______________________________________________________________________ „ UPSTREAM NODE ELEVATION = 330.00 DOWNSTREAM NODE ELEVATION = 311.00 . CHANNEL LENGTH THRU SUBAREA(FEET) = 520.00 CHANNEL SLOPE = .0365 " CHANNEL BASE(FEET) = 2.00 "Z" FACTOR = 2.000 MANNING'S FACTOR = .030 MAXIMUM DEPTH(FEET) = 2.00 CHANNEL FLOW THRU SUBAREA(CFS) = 8.85 • FLOW VELOCITY(FEET/SEC) = 5.05 FLOW DEPTH(FEET) = .56 TRAVEL TIME(MIN.) = 1.72 TC(MIN.) = 12.70 • ***************************************************************************** , FLOW PROCESS FROM NODE 125.00 TO NODE 130.00 IS CODE = 8 • >»»ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<«« 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.754 SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 SUBAREA AREA(ACRES) = 7.10 SUBAREA RUNOFF(CFS) = 14.66 TOTAL AREA(ACRES) = 10.90 TOTAL RUNOFF(CFS) = 23.51 TC(MIN) = 12.70 r*************'************************** ,„ FLOW PROCESS FROM NODE 130.00 TO NODE 110.00 IS CODE = >»»COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<«« »»>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) DEPTH OF FLOW IN 24.0 INCH PIPE IS 15.0 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 11.4 UPSTREAM NODE ELEVATION = 308.12 DOWNSTREAM NODE ELEVATION = 307.64 FLOWLENGTH(FEET) = 20.30 MANNING'S N = .013 ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES PIPEFLOW THRU SUBAREA(CFS) = 23.51 TRAVEL TIME(MIN.) = .03 TC(MIN.) = 12.73 r*************************************************** ************ FLOW PROCESS FROM NODE 130.00 TO NODE 110.00 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 TIME OF CONCENTRATION(MIN.) = 12.73 RAINFALL INTENSITY(INCH/HR) = 3.75 TOTAL STREAM AREA(ACRES) = 10.90 PEAK FLOW RATE(CFS) AT CONFLUENCE = 23.51 2 ARE ** CONFLUENCE DATA ** STREAM RUNOFF Tc NUMBER (CFS) (MIN.) 1 5.31 17.35 2 23.51 12.73 INTENSITY (INCH/HOUR) 3.070 3.749 AREA (ACRE) 2 .00 10.90 RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc NUMBER (CFS) (MIN.) 1 27.86 12.73 2 24.57 17.35 INTENSITY (INCH/HOUR) 3.749 3.070 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS PEAK FLOW RATE(CFS) = 27.86 Tc(MIN.) = TOTAL AREA(ACRES) = 12.90 12 .73 **************************************************************************** • FLOW PROCESS FROM NODE 110.00 TO NODE 160.00 IS CODE = 3 »»>COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA«<« >»»USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) DEPTH OF FLOW IN 21.0 INCH PIPE IS 17.1 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 13.3 UPSTREAM NODE ELEVATION = 307.31 DOWNSTREAM NODE ELEVATION = 304.75 ^ FLOWLENGTH(FEET) = 73.25 MANNING'S N = .013 ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1 „, PIPEFLOW THRU SUBAREA(CFS) = 27.86 TRAVEL TIME(MIN-) = .09 TC(MIN.) = 12.82«• ****************************************************************************** - FLOW PROCESS FROM NODE 110.00 TO NODE 160.00 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.) = 12.82 "" RAINFALL INTENSITY (INCH/HR) = 3.73 TOTAL STREAM AREA(ACRES) = 12.90 *" PEAK FLOW RATE(CFS) AT CONFLUENCE = 27.86 «• ,m**************************************************************************** FLOW PROCESS FROM NODE 155.00 TO NODE 155.00 IS CODE = 7•urn _ >»»USER SPECIFIED HYDROLOGY INFORMATION AT NODE<«« *• USER-SPECIFIED VALUES ARE AS FOLLOWS: TC(MIN) = 12.16 RAIN INTENSITY(INCH/HOUR) = 3.86 "" TOTAL AREA (ACRES) = 5.70 TOTAL RUNOFF (CFS) = 12.35 m FLOW PROCESS FROM NODE 155.00 TO NODE 160.00 IS CODE = 3m >»»COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<«« - »>»USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) <«« DEPTH OF FLOW IN 18.0 INCH PIPE IS 13.1 INCHES •'* PIPEFLOW VELOCITY (FEET/SEC.) = 8.9 - UPSTREAM NODE ELEVATION = 314.74 DOWNSTREAM NODE ELEVATION = 305.23 „ FLOWLENGTH(FEET) = 482.23 MANNING'S N = .013 ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1- PIPEFLOW THRU SUBAREA(CFS) = 12.35 TRAVEL TIME(MIN.) = .90 TC(MIN.) = 13.06•• m **************************************************************************** <* FLOW PROCESS FROM NODE 155.00 TO NODE 160.00 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. ) = 13.06 m RAINFALL INTENSITY(INCH/HR) = 3.69 TOTAL STREAM AREA(ACRES) = 5.70 « PEAK FLOW RATE(CFS) AT CONFLUENCE = 12.35 ""* ** CONFLUENCE DATA ** ,_ STREAM RUNOFF Tc INTENSITY AREA ^ NUMBER 1 2 (CFS) 27.86 12.35 (MIN.; 12.82 13.06 (INCH/HOUR) 3.731 3.688 (ACRE) 12.90 5.70 RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc NUMBER (CFS) (MIN.) 1 40.07 12.82 2 39.89 13.06 INTENSITY (INCH/HOUR) 3.731 3.688 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS PEAK FLOW RATE(CFS) = 40.07 Tc(MIN.) = TOTAL AREA(ACRES) = 18.60 12.82 ************************* - FLOW PROCESS FROM NODE 160.00 TO NODE ************************** 135.00 IS CODE = 3 »>»COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<«« >»»USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) DEPTH OF FLOW IN 24.0 INCH PIPE IS 15.1 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 19.2 UPSTREAM NODE ELEVATION = 304.42 DOWNSTREAM NODE ELEVATION = 304.07 FLOWLENGTH(FEET) = 5.25 MANNING'S N = ESTIMATED PIPE DIAMETER(INCH) = 24.00 PIPEFLOW THRU SUBAREA(CFS) = 40.07 TRAVEL TIME(MIN.) = .00 TC(MIN.) = 12.83 .013 NUMBER OF PIPES [I*******************************- FLOW PROCESS FROM NODE 160.00 TO NODE **************** *********** 135.00 IS CODE = 1 »>»DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<«« TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM TIME OF CONCENTRATION(MIN.) = 12.83 RAINFALL INTENSITY(INCH/HR) = 3.73 TOTAL STREAM AREA(ACRES) = 18.60 PEAK FLOW RATE(CFS) AT CONFLUENCE = 40.07 1 ARE: **************************************************************************** FLOW PROCESS FROM NODE 140.00 TO NODE 145.00 IS CODE = 21 • >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 INITIAL SUBAREA FLOW-LENGTH = 425.00 UPSTREAM ELEVATION = 363.92 DOWNSTREAM ELEVATION = 356.25 ELEVATION DIFFERENCE = 7.67 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.139 16.764 SUBAREA RUNOFF(CFS) = TOTAL AREA(ACRES) = 1.29 .75 TOTAL RUNOFF(CFS) =1.29 ********************************•*********: FLOW PROCESS FROM NODE 145.00 TO NODE 135.00 IS CODE = >»»COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA«<« UPSTREAM ELEVATION = 356.25 STREET LENGTH(FEET) = 694.60 STREET HALFWIDTH(FEET) = 42.00 DOWNSTREAM ELEVATION = CURB HEIGHT(INCHES) = 6 318.08 DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK = INTERIOR STREET CROSSFALL(DECIMAL) = .020 OUTSIDE STREET CROSSFALL(DECIMAL) = .020 21.00 *. SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1 **TRAVELTIME COMPUTED USING MEAN FLOW(CFS) = STREETFLOW MODEL RESULTS: STREET FLOWDEPTH(FEET) = .26 „ HALFSTREET FLOODWIDTH(FEET) = 6.88 AVERAGE FLOW VELOCITY(FEET/SEC.) = 4.48 * PRODUCT OF DEPTH&VELOCITY = 1.18 STREETFLOW TRAVELTIME(MIN) = 2.59 TC(MIN) = 19.35•*> .m 100 YEAR RAINFALL INTENSITY (INCH/HOUR) = 2.862 SOIL CLASSIFICATION IS "D" * INDUSTRIAL DEVELOPMENT RUNOFF COEFFICIENT = .9500 SUBAREA AREA(ACRES) = 1.00 SUBAREA RUNOFF(CFS) = ** SUMMED AREA (ACRES) = 1.75 TOTAL RUNOFF (CFS) = m END OF SUBAREA STREETFLOW HYDRAULICS: DEPTH(FEET) = .29 HALFSTREET FLOODWIDTH(FEET) = * FLOW VELOCITY(FEET/SEC.) = 5.14 DEPTH*VELOCITY = 2 .65 2 .72 4.01 14 1.49 ************************************************************ FLOW PROCESS FROM NODE 145.00 TO NODE 135.00 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 TIME OF CONCENTRATION(MIN.) = 19.35 RAINFALL INTENSITY(INCH/HR) = 2.86 TOTAL STREAM AREA(ACRES) = 1.75 PEAK FLOW RATE(CFS) AT CONFLUENCE = 4.01 2 ARE: ** CONFLUENCE DATA ** STREAM RUNOFF Tc NUMBER (CFS) (MIN.) 1 40.07 12.83 2 4.01 19.35 INTENSITY (INCH/HOUR) 3.730 2.862 AREA (ACRE) 18.60 1.75 <* RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM NUMBER 1 2 RUNOFF (CFS) 43 .15 34.75 Tc (MIN. ) 12.83 19.35 INTENSITY (INCH/HOUR) 3.730 2.862 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS PEAK FLOW RATE(CFS) = 43.15 Tc(MIN.) = TOTAL AREA(ACRES) = 20.35 12 .83 **************************************************************************** FLOW PROCESS FROM NODE 135.00 TO NODE 165.00 IS CODE = 3 »>»COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<«« " »>»USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) <«« . DEPTH OF FLOW IN 18.0 INCH PIPE IS 11.4 INCHES PIPEFLOW VELOCITY(FEET/SEC.) UPSTREAM NODE ELEVATION = DOWNSTREAM NODE ELEVATION = FLOWLENGTH(FEET) = 107.11 = 36.6 303.74 265.87 MANNING'S ESTIMATED PIPE DIAMETER(INCH) = 18.00 PIPEFLOW THRU SUBAREA(CFS) = 43.15 TRAVEL TIME(MIN.) = .05 TC(MIN.) = N = .013 NUMBER OF PIPES 12.88 END OF STUDY SUMMARY: PEAK FLOW RATE(CFS) = TOTAL AREA(ACRES) = 43.15 20.35 Tc(MIN.) = 12.88 END OF RATIONAL METHOD ANALYSIS IV LA COUNTY PUBLIC WORKS STORM DRAIN ANALYSIS REPT: PC/RD4412.1 (INPUT) DATE: 07/01/99 « PAGE 1 PROJECT: POINSETTIA LANE REACH C DESIGNER: DAB,;«*# ,.,CD L2 MAX Q ADJ Q LENGTH PL 1 FL 2 CTL/TW D W S KJ KE KM LC LI L3 L4 Al A3 A4 J N ""* 8 1 268.37 <«w 2 2 43.1 43.1 107.11 265.87 303.74 0.00 30. 0. 3 0.05 0.00 0.00 1 3 0 0 0. 0. 0. 4.00 0.013 -•*« 2 3 31.9 31.9 5.25 304.07 304.42 0.00 24. 0. 3 0.05 0.00 0.00 0 4 20 0 90. 0. 0. 4.00 0.013 ^2 4 12.4 12.4 270.13 305.23 312.85 0.00 18. 0. 3 0.05 0.00 0.00 0 5 0 0 15. 0. 0. 4.00 0.013 «, 2 5 12.4 12.4 211.59 313.18 314.24 0.00 18. 0. 1 0.00 0.20 0.00 0 0 0 0 0. 0. 0. 0.00 0.013 "** 2 20 27.9 27.9 73.25 304.75 307.31 0.00 24. 0. 3 0.05 0.00 0.00 3 21 0 0 5. 0. 0. 4.00 0.013 m 2 21 23.5 23.5 20.30 307.64 311.20 0.00 24. 0. 1 0.00 0.20 0.00 0 0 0 0 0. 0. 0. 0.00 0.013 4* LA COUNTY PUBLIC WORKS STORM DRAIN ANALYSIS (INPUT) KEPT: PC/RD4412.1 DATE: 07/01/99 PAGE 1 "PROJECT: POINSETTIA LANE REACH C DESIGNER: DAB • CD L2 MAX Q ADJ Q LENGTH FL 1 FL 2 CTL/TW D W S KJ KE KM LC LI L3 L4 Al A3 A4 J 8 1 268.37 2 2 43.1 43.1 107.11 265.87 303.74 0.00 30. 0. 3 0.05 0.00 0.00 1 3 0 0 0. 0. 0. 4.00 0.013 2 3 31.9 31.9 5.25 304.07 304.42 0.00 24. 0. 3 0.05 0.00 0.00 0 4 20 0 90. 0. 0. 4.00 0.013 2 4 12.4 12.4 270.13 305.23 312.85 0.00 18. 0. 3 0.05 0.00 0.00 0 5 0 0 15. 0. 0. 4.00 0.013 2 5 12.4 12.4 211.59 313.18 314.24 0.00 18. 0. 1 0.00 0.20 0.00 0 0 0 0 0. 0. 0. 0.00 0.013 2 20 27.9 27.9 73.25 304.75 307.31 0.00 24. 0. 3 0.05 0.00 0.00 3 21 0 0 5. 0. 0. 4.00 0.013 2 21 23.5 23.5 20.30 307.64 311.20 0.00 24. 0. 1 0.00 0.20 0.00 0 0 0 0 0. 0. 0. 0.00 0.013 LA COUNTY PUBLIC WORKS STORM DRAIN ANALYSIS (INPUT) REPT: PC/RD4412.1 DATE: 07/01/99 PAGE 1 *• PROJECT: POINSETTIA LANE REACH C DESIGNER: DAB f«M ^ CD L2 MAX Q ADJ Q LENGTH FL 1 FL 2 CTL/TW D W S KJ KE KM LC LI L3 L4 Al A3 A4 J 8 1 268.37 2 2 43.1 43.1 107.11 265.87 303.74 0.00 30. 0. 3 0.05 0.00 0.00 1 3 0 0 0. 0. 0. 4.00 0.013 2 3 31.9 31.9 5.25 304.07 304.42 0.00 24. 0. 3 0.05 0.00 0.00 0 4 20 0 90. 0. 0. 4.00 0.013 2 4 12.4 12.4 270.13 305.23 312.85 0.00 18. 0. 3 0.05 0.00 0.00 500 15. 0. 0. 4.00 0.013 2 5 12.4 12.4 211.59 313.18 314.24 0.00 18. 0. 1 0.00 0.20 0.00 0 0 0 0 0. 0. 0. 0.00 0.013 2 20 27.9 27.9 73.25 304.75 307.31 0.00 24. 0. 3 0.05 0.00 0.00 3 21 0 0 5. 0. 0. 4.00 0.013 2 21 23.5 23.5 20.30 307.64 311.20 0.00 24. 0. 1 0.00 0.20 0.00 0 0 0 0 0. 0. 0. 0.00 0.013 INTERNAL ENERGY DISSIPATOR RING DESIGN FOR 30" RCP PIPE DIAMETER = 30 INCHES SELECT RING HEIGHT FOR THE THREE DOWNSTREAM ELEMENTS: 0.06*D < Kd < 0.09*D D = pipe diameter (inches) Kd = ring height of downstream elements (inches) 1.44 <Ku <2.16 | SELECT Kd = 2.0 inches |Use 3" ring height as standard size SELECT A RING HEIGHT FOR THE SINGLE UPSTREAM ELEMENT: 0.12*D<Ku <0.18*D 2.88 <Ku <5.00 | SELECT Ku = 2Kd = 4 inches |Use 3" ring height as standard size SELECT THE SPACING. Ld. FOR THE THREE DOWNSTREAM ELEMENTS: 1.5*D<Ld<2.5*D 3.00 < Ld < 5.00 Ld = spacing from downstream elements (feet) SELECT Ld = 4 feet SELECT THE SPACING. Lu. FOR THE SINGLE UPSTREAM ELEMENT: 2 Ld < Lu < 2 Ld 6.00 <Lu< 10.00' | SELECT Lu = 2*Ld = 8 feet [where Lu = spacing from upstream elements (feet) OUTLET PIPES LENGTH = 24 feet (assuming width of each ring = 2 ft) DETERMINE CROSS SECTIONAL AREA AT LAST DOWNSTREAM ELEMENT: Dd = D - 2(3") = 24 inches Area = 3.14 ftA2 DETERMINE THE REDUCED OUTLET VELOCITY. Vd: STORM LINE B DESIGN FLOWRATE Q (cfs) 43.1 VELOCITY Vd(FPS) 13.7 V POINSETTIA LANE CURB INLET SIZING BASED ON THE CITY OF SAN DIEGO DRAINAGE DESIGN MANUAL INLET TYPE FLOW-BY FLOW-BY INLET # 1 2 NODE 110 135 STREET SLOPE 6.3% 6.3% Q(CFS) 5.3 4.0 a(in.) 0.33 0.33 y(in.) 0.29 0.27 L(ft.) (INLET SIZE) 15.5 12.3 USE (ft.) 17 14 SAMPLE FLOW-BY CALCULATION Q=11.3CFS SLOPE=4.0% Y=.39 USING EQUATION Q=0.7L(0.33+DEPTH)A3/2 DEPTH=Y(FROM CITY OF SAN DIEGO CHART 1-104.12) SOLVING FOR L L=17' ADD LOFT FOR DESIGN CONSIDERATIONS L=18' FROM CITY OF SAN DIEGO CHART 1-103.6C SAMPLE SUMP CALCULATIONS Q=3.6 CFS H= PONDED DEPTH=10 IN. h= HEIGHT OF CURB=6 in SOLVING FOR L H/h=1.7 L = 5.0 feet Q\L=H\h :DB H:\EXCEL\2322\INLETS.XLS WO 2322-1 3/18/99 50 100 Discharge, ft3/sec 0.1 0.2 0.3.0.4 0.6 0.8 .1 2 3 4 5 6 7 8 10 15 2025 Discharge, m-Vsec Fig. 7.45 Design of riprap outlet protection from a round pipe flowing full; minimum tailwater conditions. (6,14) to find the riprap size and apron length. The apron width at the pipe end should be 3 times the pipe diameter. Where there is a well-defined channel immediately downstream from the apron, the width of the downstream end of the apron should be equal to the width of the channel. Where there is no well-defined chan- nel immediately downstream from the apron, minimum tailwater conditions apply and the width of the downstream end of the apron should be equal to the pipe diameter plus the length of the apron. EXAMPLE 7.4 Riprap Outlet Protection Design Calculation for Minimum Tailwater Condition Given: A flow of 6 ft'Vsec (0.17 mVsec) discharges from a 12-in (30-cm) pipe onto a 2 percent grassy slope with no defined channel. Find: The required length, width, and median stone size d5Q for a riprap apron. HE/40 W/)LL CALCULATION AT MODE 130 co UJ Xoz (CUJ 3O rr UJ H UlZ< O I80 I68 I56 144 I32 I20 (08 - 96 - 84 - 72 - 60 - 54 - 48 - 21 - 18 - 15 "- 12 IO.OOO 8,000 6.0OO 5,000 4,000 3,000 r- 2.000 I.OOO 800 HV = 311.71 EXAMPLE 0*42 Inch** (3.5 foat) 0*120 c<i (I) (2) O) us *o Z.5 2.1 2.2 *D In ftat MW 'Mi s.s 7.4 7.7 6 5 4 - 3 r 2 *- I.O Ta til* teal* (2) «r (3) pra)*et hor|j»ntdllj le ictl* (l),th«n HI* tlralad* Inclifltd tin* thravfd 0 and -0 iealt*,or r**art« •« iltuitrottd. CHART 1 (I) (2) (3) O t — '- - s %tr UJ UJ2 2 z Q. U.'Ci euj HEAOWJ-6. - 5. — 4. -3. - 2. - I.5 - I.O - .9 - .8 - .7 - .5 — b. - 5. - 4. :5- - - -I.5 - - I.O - .9 - .8 - .6 -.5 - 6. - 5. 74. -3. — 2. -I.5 _ i.o - .9 - .8 — .7 - .6 -.5 BUREAU OF PUBLIC *OAOS JAN 1963 HEADWATER SCALES 263 REVISED MAY 1964 HEADWATER DEPTH FOR CONCRETE PIPE CULVERTS WITH INLET CONTROL 181 VI REFERENCE DATA NOTE: Some reference data that has typically been included in support of hydrologic calculations done by hand are incorporated into the Rational Method Hydrology Computer Program Package (by AES). These include: a Intensity-Duration Design Chart a Nomograph for Determination of Time of Concentration (Tc) for Natural Watersheds a Urban Areas Overland Time of Flow Curves a Runoff Coefficients (Rational Method) Since these references are incorporated into the AES software, they are not needed to support this study and are therefore not included in this report. Soils maps are also not included, as Hydrologic Soil Group "D" was used for this study. COVrtt'Y OF SAN DIEGO DEPARTMENT OF SANITATION FLOOD CONTROL 33' 100-YEAR 6-HOUR PRECIPITATION OF 100-YEAR 6-HOURISOPLUVIALS PRECiPiTATIOf! JM KMTHS OF AM liiCi U.S. DEPARTMEN NATIONAL OCt'ANIC AMD AT: SPECIAL STUDIES URANCH. OTFICn OF If 27.o£fr^¥£ <f by C OF COMMERCE OSJ'IIEHIC ADMINISTRATION DROLOCV. NATIONAL WEATHER SERVICE 30'_ RESIDENTIAL STREET ONE SIDE ONLY 0.4 — I I I I I I I I 5 6 7 8 9 10 DISCHARGE (CFS) 20 30 40 50 EXAMPLE: Given: Q= 10 S= 2.5% Chart gives; Depth = 0.4, Velocity = 4.4 f.p.s. SAN DIEGO COUNTY DEPARTMENT OF SPECIAL DISTRICT SERVICES APPROVED DESIGN MA NUAL ft, GUTTEf: AND ROADWAY DISCHARGE-VELOCITY CHART DATE APPENDIX X-D PORTION OF HYDRDLO&Y 5TI/OY FOR D£ J0/M£ PROPERTY £HT 1 ***************************************************************************** „ FLOW PROCESS FROM NODE 21.00 TO NODE 22.00 IS CODE = 6 - »»>COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA<«« *" UPSTREAM ELEVATION = 335.00 DOWNSTREAM ELEVATION = 328.00 - STREET LENGTH(FEET) = 290.00 CURB HEIGHT(INCHES) =6. STREET HALFWIDTH(FEET) = 18.00 DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK = 9.00 *** INTERIOR STREET CROSSFALL (DECIMAL) = .020 _ OUTSIDE STREET CROSSFALL(DECIMAL) = .020 - SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1 **TRAVELTIME COMPUTED USING MEAN FLOW(CFS) = 4.42 STREETFLOW MODEL RESULTS: STREET FLOWDEPTH(FEET) = .34 HALFSTREET FLOODWIDTH(FEET) = 10.52 AVERAGE FLOW VELOCITY(FEET/SEC.) = 3.61 PRODUCT OF DEPTH&VELOCITY = 1.21 . STREETFLOW TRAVELTIME(MIN) = 1.34 TC(MIN) = 12.09 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.876 SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 ,„ SUBAREA AREA (ACRES) = 2.20 SUBAREA RUNOFF (CFS) = 4.69 SUMMED AREA(ACRES) = 3.10 TOTAL RUNOFF(CFS) = 6.76 - END OF SUBAREA STREETFLOW HYDRAULICS: DEPTH(FEET) = .38 HALFSTREET FLOODWIDTH(FEET) = 12.59 "*"" FLOW VELOCITY(FEET/SEC.) = 3.97 DEPTH*VELOCITY = 1.50 ******************************************************************************* FLOW PROCESS FROM NODE 22.00 TO NODE 13.00 IS CODE = 3 ,, >»»COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<«« >»»USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) <«« ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000 """" DEPTH OF FLOW IN 18.0 INCH PIPE IS 9.9 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 6.8 UPSTREAM NODE ELEVATION = 322.40 — DOWNSTREAM NODE ELEVATION = 322.00 FLOWLENGTH(FEET) = 30.00 MANNING'S N = .013 •" ESTIMATED PIPE DIAMETER (INCH) = 18.00 NUMBER OF PIPES = 1 ,, PIPEFLOW THRU SUBAREA (CFS) = 6.76 TRAVEL TIME(MIN.) = .07 TC(MIN.) = 12.16 :***************FLOW PROCESS FROM NODE 22.00 TO NODE 13.00 IS CODE = 1 >»»DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<«« >»»AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<«« SEE $tf££T rGZ. RE5I/IT.5 TOTAL NUMBER OF STREAMS = 2 1/5 ED IN TblS STL/DY CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = 12.16 P0RT10M OF l\1DR.OLD£,1 5T(/DY FOR. Df Jflflfi PROPERTY RAINFALL INTENSITY(INCH/HR) = 3.86 *" TOTAL STREAM AREA (ACRES) = 3.10 PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.76 - ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA "" NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 5.65 12.35 3.823 2.60 2 6.76 12.16 3.861 3.10 **» 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 12.35 12.16 3.861 2 12.34 12.35 3.823 - COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 12.35 Tc(MIN.) - 12.16 ~" fOTAL AREA (ACRES) = 5.70 ilNlFOiUYvATlOlV L/S£D F0R. CODE7 AT N0DE 1ST M* *************************************************************************** FLOW PROCESS FROM NODE 13.00 TO NODE 14.00 IS CODE = 3 »>»COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<«« >»»USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) <«« DEPTH OF FLOW IN 21.0 INCH PIPE IS 15.2 INCHES "" PIPEFLOW VELOCITY (FEET/SEC.) = 6.6 UPSTREAM NODE ELEVATION = 322.00 DOWNSTREAM NODE ELEVATION = 317.90 — FLOWLENGTH(FEET) = 460.00 MANNING'S N = .013 ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1 "" PIPEFLOW THRU SUBAREA(CFS) = 12.35 _ TRAVEL TIME(MIN.) = 1.15 TC(MIN.) = 13.32 * FLOW PROCESS FROM NODE 13.00 TO NODE 14.00 IS CODE = 1 m »>»DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««< TOTAL NUMBER OF STREAMS = 3 *» CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: m TIME OF CONCENTRATION(MIN.) = 13.32 RAINFALL INTENSITY(INCH/HR) = 3.64 .„ TOTAL STREAM AREA (ACRES) = 5.70 PEAK FLOW RATE(CFS) AT CONFLUENCE = 12.35 •m *** *************************************************************************** * FLOW PROCESS FROM NODE 30.00 TO NODE 31.00 IS CODE = 21 - >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< - SOIL CLASSIFICATION IS "D" , SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 MASTGR NOT A (PARK