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Home My WebLink AboutW.O. 2308-2; Carnation Property-Spectrum Communities; Carnation Property; 1998-12-07HUN SAKE R &ASSOCIATES SAN DIEGO, INC. PLANNING ENGINEERING SURVEYING IRVINE LAS VEGAS RIVERSIDE SAN DIEGO HYDROLOGY STUDY For CARNATION PROPERTY City of Carlsbad, California Prepared for: Spectrum Communities 15375 Barranca Parkway Suite B-211 Irvine, CA 92618 W.O. 2308-2 December/, 1998 DAVE HAMMAR JACK HILL LEXWILLIMAN 10179 Huennekens St. Suite 200 San Diego, CA 92121 (619)558-4500 PH (619) 558-1414 FX www.hunsaker.com lnfo@HunsakerSD.com Hunsaker & Associates San Diego, Inc. David A. Hammar, R.C.E. President RA:kd:mswoi*h:\aes92\2308\2\hyd.doc W.O. 2308-1 12/10/88 Carnation Property Hydrology Report TABLE OF CONTENTS References Introduction Executive Summary Vicinity Map Drainage Criteria and Methodology 100-year Post-Development Hydrology Study Hydraulics Analysis Reference Data Post-Development Hydrology Map SECTION I I I IV V VI (pocket) RA:kd :mswor*h:\aes92\2308\2\hyd.doc W.0.2308-1 12/10/98 Carnation Property Hydrology Report References 1) The County of San Diego Drainage Design & Procedure Manual, 1993 2) The County of San Diego Department of Public Works, Public Roads Standards, 1992 3) P&D Technologies, Grading, Erosion Control Plans & Storm Drain Plans For Aviara PA 24 CT 90-15, Drawings #322-2A, Sheet 30 of 32 Introduction Carnation Property lies within the City of Carlsbad, California. Development is proposed east of Interstate 5, north of Batiquitos Lagoon, and south of Palomar Airport Road (see Fig. 1). The subject project consists of 10 acres, made up entirely of residential single family homes. The site is tributary to an existing 24" RCP within Nightshade Road (per dwg. 322-2A), which has been constructed to convey a 100-year storm. The existing storm drain was designed to carry 19.3 c.f.s. Since the proposed runoff from this development exceeds the design value, a hydraulics analysis was conducted to determine the functionality of the 24" RCP. Therefore, the scope of work includes: • Determination of 100-year peak discharge. • Hydraulics Analysis. Executive Summary Per The County of San Diego Department of Public Works, Public Works Standards, 1992, all street flow is contained below top of curb. The hydraulics analysis verifies the existing storm drain does not require upsizing or any other modifications. The proposed storm drainage system collecting flow tributary to the site is not final design and is subject to change. RA:kd :msword\h:\aes92\2308\2\hyd.doc W.0.2308-1 12/10/98 CARNATION PROPERTY CITY OF SAN MARCOS VICINITY MAP A/.r.s. F/GJ Ill Carnation Property Hydrology Report Drainage Criteria and Methodology Design Storm 100-year storm Land Use Single-family Soil Type A hydrologic soil group "D" was used for this study. Runoff Coefficient "C" values were based on the County of San Diego Drainage Design & Procedure Manual. The site is single- family residential, therefore a "C" value of 0.55 was used. Rainfall Intensity The rainfall intensity values were based on the criteria presented in the County of San Diego Drainage Design & Procedure Manual (see Reference Data). RA:kd :msword\h:\aes92\2308\2\hyd.doc W.0.2308-1 12/10/98 Carnation Property Hydrology Report HYDROLOGY METHOD OF ANALYSIS The computer-generated analysis for this watershed is consistent with current engineering standards and requirements of the County of San Diego. 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 concentration. 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 that discharge into different designated drainage basins. These "sub-basins" depend upon locations of inlets and ridgelines. 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: RA:kd :msword\h:\aes92\2308\2\hyd.doc W.0.2308-1 12/10/98 Carnation Property Hydrology Report (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. (3) Using T, determine the corresponding values of I. Then Q = C I A. (4) Using Q, estimate the travel time between this node and the next by Manning's equation as applied to the particular channel or conduit linking the two nodes. The nodes are joined together by links, which may be street gutter flows, drainage swales or drainage ditches. These links are characterized by length, area, runoff coefficient and cross-section. The Computer subarea menu is as follows: Enter Upstream node number Enter Downstream node number SUBAREA HYDROLOGIC PROCESS 1. Confluence analysis at node. 2. Initial subarea analysis. 3. Pipeflow travel time (computer estimated). 4. Pipeflow travel time (user specified). 5. Trapezoidal channel travel time. 6. Street flow analysis through subarea. 7. User - specified information at node. 8. Addition of sub area runoff to main line. 9. V-gutter flow through area. Select subarea hydrologic process The engineer enters in the pertinent nodes, and then the hydrologic process. Where two or more links join together, the node is analyzed by the confluence method described as follows: m •** RA:kd :msword\h:\aes92\230a2\nyd.doc W.O. 2308-1 12/10/96 Carnation Property Hydrology Report At the confluence point of two or more basins, the following procedure is used to adjust the total summation of peak flow rates to allow for differences in basin times of concentration. This adjustment is based on the assumption that each basin's hydrographs are triangular in shape. (1). If the collection streams have the same times of concentration, then the Q values are directly summed, Qp = Qa + Qb; Tp = Ta = Tb (2). If the collection streams have different times of concentration, the smaller of the tributary Q values may be adjusted as follows: (i). The most frequent case is where the collection stream with the longer time of concentration has the larger Q. The smaller Q value is adjusted by the ratio of rainfall intensities. Qp = Qa + Qb (la/lb); Tp = Ta In some cases, the collection stream with the shorter time of concentration has the larger Q. Then the smaller Q is adjusted by a ratio of the T values. Qp = Qb+Qa (Tb/Ta); Tp = Tb In a similar way, the underground storm drains are analyzed. The data obtained from the surface model for the flow rates present at the inlets and collection points are input into the nodes representing those structures. The design grades and lengths are used to compute the capacity of the storm drains and to model the travel time into the adjustment of the times of concentration for downstream inlets. REFERENCE 1. Hydrology Manual, County of San Diego, January 1985. 2. Hromadka, Theodore: COMPUTER METHODS IN URBAN HYDROLOGY: Lighthouse Publications, 1983. RA:kd :mswoi«h:\aes92\2308\2\hyd.doc W.0.2308-1 12/10/98 IV 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 ************************** * CARNATION * * 100-YEAR POST-DEVELOPMENT HYDROLOGY STUDY * * W.O. #2308-2 * ************************************************************************** FILE NAME: 2308\2\POST100.RAT TIME/DATE OF STUDY: 18:45 12/ 9/1998 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: 1985 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENT(YEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 2.700 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 9.00 TO NODE 10.00 IS CODE = 21 >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« =======:==:=:===========::=: =s======:==:= SB======== = =;—=::=;===============:=:===;== SOIL CLASSIFICATION IS "D" INDUSTRIAL DEVELOPMENT RUNOFF COEFFICIENT = .9500 INITIAL SUBAREA FLOW-LENGTH = 400.00 UPSTREAM ELEVATION = 380.80 DOWNSTREAM ELEVATION = 370.80 ELEVATION DIFFERENCE = 10.00 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 3.979 TIME OF CONCENTRATION ASSUMED AS 5-MINUTES 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.114 SUBAREA RUNOFF(CFS) = 1.35 TOTAL AREA(ACRES) = .20 TOTAL RUNOFF(CFS) = 1.35 FLOW PROCESS FROM NODE 10.00 TO NODE 11.00 IS CODE = 6 >»»COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA<«« UPSTREAM ELEVATION = 370.80 DOWNSTREAM ELEVATION = 346.50 STREET LENGTH(FEET) = 500.00 CURB HEIGHT(INCHES) = 6. STREET HALFWIDTK(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) = 7.04 STREETFLOW MODEL RESULTS: STREET FLOWDEPTH(FEET) = .35 HALFSTREET FLOODWIDTK(FEET) = 11.04 AVERAGE FLOW VELOCITY(FEET/SEC.) = 5.27 PRODUCT OF DEPTH&VELOCITY = 1.83 STREETFLOW TRAVELTIME(MIN) = 1.58 TC(MIN) = 6.58 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.958 SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 SUBAREA AREA(ACRES) = 3.40 SUBAREA RUNOFF(CFS) = 11.14 SUMMED AREA(ACRES) = 3.60 TOTAL RUNOFF(CFS) = 12.49 END OF SUBAREA STREETFLOW HYDRAULICS: DEPTH(FEET) = .41 HALFSTREET FLOODWIDTH(FEET) = 14.13 FLOW VELOCITY(FEET/SEC.) = 5.91 DEPTH*VELOCITY = 2.41 FLOW PROCESS FROM NODE 11.00 TO NODE 14.00 IS CODE = 6 >»»COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA<«« UPSTREAM ELEVATION = 346.50 DOWNSTREAM ELEVATION = 331.30 STREET LENGTH(FEET) = 240.00 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) = 12.80 STREETFLOW MODEL RESULTS: STREET FLOWDEPTH-(FEET) = .40 HALFSTREET FLOODWIDTH(FEET) = 13.62 AVERAGE FLOW VELOCITY(FEET/SEC.) = 6.49 PRODUCT OF DEPTH&VELOCITY = 2.59 STREETFLOW TRAVELTIME(MIN) = .62 TC(MIN) = 7.20 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.624 SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 SUBAREA AREA(ACRES) = .20 SUBAREA RUNOFF(CFS) = .62 SUMMED AREA(ACRES) = 3.80 TOTAL RUNOFF(CFS) = 13.11 END OF SUBAREA STREETFLOW HYDRAULICS: DEPTH(FEET) = .40 HALFSTREET FLOODWIDTH(FEET) = 13.62 FLOW VELOCITY(FEET/SEC.) = 6.65 DEPTH*VELOCITY = 2.65 FLOW PROCESS FROM NODE 11.00 TO NODE 14.00 IS CODE = 1 >»»DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<«« TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = 7.20 RAINFALL INTENSITY(INCH/HR) = 5.62 TOTAL STREAM AREA(ACRES) = 3.80 PEAK FLOW RATE(CFS) AT CONFLUENCE = 13.11 FLOW PROCESS FROM NODE 12.00 TO NODE 13.00 IS CODE = 21 >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 INITIAL SUBAREA FLOW-LENGTH = 245.00 UPSTREAM ELEVATION = 338.20 DOWNSTREAM ELEVATION = 334.00 ELEVATION DIFFERENCE = 4.20 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 12.948 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.851 SUBAREA RUNOFF(CFS) = 1.91 TOTAL AREA(ACRES) = .90 TOTAL RUNOFF(CFS) = 1.91 t****************** ******************************************************** FLOW PROCESS FROM NODE 13.00 TO NODE 14.00 IS CODE = 6 >»»COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA<«« UPSTREAM ELEVATION = 334.00 DOWNSTREAM ELEVATION = 331.30 STREET LENGTH(FEET) = 250.00 CURB HEIGHT(INCHES) = 6. STREET HALFWIDTK(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) = 2.88 STREETFLOW MODEL RESULTS: STREET FLOWDEPTH(FEET) = .34 HALFSTREET FLOODWIDTH(FEET) = 10.52 AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.35 PRODUCT OF DEPTH&VELOCITY = .79 STREETFLOW TRAVELTIME(MIN) = 1.77 TC(MIN) = 14.72 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.545 SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 SUBAREA AREA(ACRES) = 1.00 SUBAREA RUNOFF(CFS) = 1.95 SUMMED AREA(ACRES) = 1.90 TOTAL RUNOFF(CFS) = 3.86 END OF SUBAREA STREETFLOW HYDRAULICS: DEPTH(FEET) = .36 HALFSTREET FLOODWIDTH(FEET) = 11.55 FLOW VELOCITY(FEET/SEC.) = 2.65 DEPTH*VELOCITY = .95 FLOW PROCESS FROM NODE 13.00 TO NODE 14.00 IS CODE = >»»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.) = 14.72 RAINFALL INTENSITY(INCH/HR) = 3.55 TOTAL STREAM AREA(ACRES) = 1.90 PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.86 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 13.11 7.20 5.624 3.80 2 3.86 14.72 3.545 1.90 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 15.54 . 7.20 5.624 2 12.12 14.72 3.545 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 15.54 Tc(MIN.) = 7.20 TOTAL AREA(ACRES) = 5.70 **************************************************************************** FLOW PROCESS FROM NODE 14.00 TO NODE 19.00 IS CODE = 3 >»»COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<«« >»»USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<«« DEPTH OF FLOW IN 21.0 INCH PIPE IS 16.2 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 7.8 UPSTREAM NODE ELEVATION = 322.00 DOWNSTREAM NODE ELEVATION = 321.40 FLOWLENGTH(FEET) = 58.00 MANNING'S N = .012 ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = PIPEFLOW THRU SUBAREA(CFS) = 15.54 TRAVEL TIME(MIN.) = .12 TC(MIN.) = 7.32 FLOW PROCESS FROM NODE 14.00 TO NODE 19.00 IS CODE = — — — _________ _______ — — ____________ ._«.____ — _ _____• .. __ — ___.__... . — _ — .« >»»DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<«« TOTAL NUMBER OF STREAMS = 3 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION (MIN. ) = 7.32 RAINFALL INTENSITY (INCH/HR) = 5.56 TOTAL STREAM AREA(ACRES) = 5.70 PEAK FLOW RATE(CFS) AT CONFLUENCE = 15.54 *********************************************************************************** FLOW PROCESS FROM NODE 15.00 TO NODE 16.00 IS CODE = 21 >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 INITIAL SUBAREA FLOW-LENGTH = 240.00 UPSTREAM ELEVATION = 362.30 DOWNSTREAM ELEVATION = 350.70 ELEVATION DIFFERENCE = 11.60 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 9.072 *CAUTION: SUBAREA•SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.844 SUBAREA RUNOFF(CFS) = 1.07 TOTAL AREA(ACRES) = .40 TOTAL RUNOFF(CFS) = 1.07 FLOW PROCESS FROM NODE 16.00 TO NODE 19.00 IS CODE = 6 >»»COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA<«« UPSTREAM ELEVATION = 350.70 DOWNSTREAM ELEVATION = 331.00 STREET LENGTH(FEET) = 365.00 CURB HEIGHT(INCHES) = 6. STREET HALFWIDTK(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) = 2.40 STREETFLOW MODEL RESULTS: STREET FLOWDEPTH(FEET) = .25 HALFSTREET FLOODWIDTH(FEET) = 6.40 AVERAGE FLOW VELOCITY(FEET/SEC.) = 4.55 PRODUCT OF DEPTH&VELOCITY = 1.16 STREETFLOW TRAVELTIME(MIN) = 1.34 TC(MIN) = 10.41 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.433 SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 SUBAREA AREA(ACRES) = 1.10 SUBAREA RUNOFF(CFS) = 2.68 SUMMED AREA(ACRES) = 1.50 TOTAL RUNOFF(CFS) = 3.75 END OF SUBAREA STREETFLOW HYDRAULICS: DEPTH(FEET) = .30 HALFSTREET FLOODWIDTH(FEET) = 8.46 FLOW VELOCITY(FEET/SEC.) = 4.49 DEPTH*VELOCITY = 1.33 r ******************************************************** FLOW PROCESS FROM NODE 16.00 TO NODE 19.00 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.) = 10.41 RAINFALL INTENSITY(INCH/HR) = 4.43 TOTAL STREAM AREA(ACRES) = 1.50 PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.75 ******************************************************************************** FLOW PROCESS FROM NODE 17.00 TO NODE 18.00 IS CODE = 21 >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 INITIAL SUBAREA FLOW-LENGTH = 205.00 UPSTREAM ELEVATION = 338.20 DOWNSTREAM ELEVATION = 334.50 ELEVATION DIFFERENCE = 3.70 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 11.642 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.124 SUBAREA RUNOFF(CFS) = 1.13 TOTAL AREA(ACRES) = .50 TOTAL RUNOFF(CFS) = 1.13 *******************************************•*•-*•*** + * + •*•*****•*•************* FLOW PROCESS FROM NODE 18.00 TO NODE 19.00 IS CODE = 6 >»»COMPUTE STREETFLOW TRAVELTIME THRU SUBAREA<«« UPSTREAM ELEVATION = ' 334.50 DOWNSTREAM ELEVATION = 331.00 STREET LENGTH(FEET) = 305.00 CURB HEIGHT(INCHES) = 6. STREET HALFWIDTK(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) = 2.36 STREETFLOW MODEL RESULTS: STREET FLOWDEPTH(FEET) = .32 HALFSTREET FLOODWIDTK(FEET) = 9.49 AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.31 PRODUCT OF DEPTH&VELOCITY = .73 STREETFLOW TRAVELTIME(MIN) = 2.20 TC(MIN) = 13.84 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.689 SOIL CLASSIFICATION IS "D" SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .5500 SUBAREA AREA(ACRES) = 1.20 SUBAREA RUNOFF(CFS) = 2.43 SUMMED AREA(ACRES) = 1.70 TOTAL RUNOFF(CFS) = 3.57 END OF SUBAREA STREETFLOW HYDRAULICS: DEPTH(FEET) = .35 HALFSTREET FLOODWIDTH(FEET) = 11.04 FLOW VELOCITY(FEET/SEC.) = 2.67 DEPTH*VELOCITY = .93 ****************************************************************************** FLOW PROCESS FROM NODE 18.00 TO NODE 19.00 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.) = 13.84 RAINFALL INTENSITY(INCH/HR) = 3.69 TOTAL STREAM AREA(ACRES) = 1.70 PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.57 ** CONFLUENCE DATA ** STREAM NUMBER 1 2 3 RAINFALL RUNOFF (CFS) 15.54 3.75 3.57 INTENSITY CONFLUENCE FORMULA ** PEAK STREAM NUMBER 1 2 3 FLOW RATE RUNOFF (CFS) 20.90 19.10 17.00 Tc (MIN. ) 7.32 10.41 13.84 AND TIME USED FOR TABLE ** Tc (MIN. ) 7.32 10.41 13.84 INTENSITY (INCH/HOUR) 5.562 4.433 3.689 OF CONCENTRATION 3 STREAMS. INTENSITY (INCH/HOUR) 5.562 4.433 3.689 AREA (ACRE) 5.70 5.70 1.70 RATIO COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 20.90 Tc(MIN.) = 7.32 TOTAL AREA(ACRES) = 8.90 ****************************************************************************** FLOW PROCESS FROM NODE 19.00 TO NODE 20.00 IS CODE = 3 >»»COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<«« >»»USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) <«« DEPTH OF FLOW IN 24.0 INCH PIPE IS 18.1 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 8.2 UPSTREAM NODE ELEVATION = 321.40 DOWNSTREAM NODE ELEVATION = 320.20 FLOWLENGTH(FEET) = 125.00 MANNING'S N = .012 ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = PIPEFLOW THRU SUBAREA(CFS) = 20.90 TRAVEL TIME(MIN.) = .25 TC(MIN.) = 7.58 ********************************************************************************** FLOW PROCESS FROM NODE 20.00 TO NODE 25.00 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 8.2 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 26.7 UPSTREAM NODE ELEVATION = 320.20 DOWNSTREAM NODE ELEVATION = 297.70 FLOWLENGTH(FEET) = 108.00 MANNING'S N = .012 ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPEFLOW THRU SUBAREA(CFS) = 20.90 TRAVEL TIME(MIN.) = .07 TC(MIN.) = 7.64 FLOW PROCESS FROM NODE 20.00 TO NODE 25.00 IS CODE = 1 >»»DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<«« TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = 7.64 RAINFALL INTENSITY(INCH/HR) = 5.41 TOTAL STREAM AREA(ACRES) = 8.90 PEAK FLOW RATE(CFS) AT CONFLUENCE = 20.90 ********************************************************** + ***** FLOW PROCESS FROM NODE 21.00 TO NODE 22.00 IS CODE = 21 >»»RATIONAL METHOD INITIAL SUBAREA ANALYSIS<«« SOIL CLASSIFICATION IS "D" RURAL DEVELOPMENT RUNOFF COEFFICIENT = .4500 NATURAL WATERSHED NOMOGRAPH TIME OF CONCENTRATION WITH 10-MINUTES ADDED = 11.29(MINUTES) INITIAL SUBAREA FLOW-LENGTH = 200.00 UPSTREAM ELEVATION = 354.00 DOWNSTREAM ELEVATION = 340.00 ELEVATION DIFFERENCE = 14.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.208 SUBAREA RUNOFF(CFS) = 1.51 TOTAL AREA(ACRES) = .80 TOTAL RUNOFF(CFS) = 1.51 **************************************************************************** FLOW PROCESS FROM NODE 22.00 TO NODE 23.00 IS CODE = 51 >»»COMPUTE TRAPEZOIDAL CHANNEL FLOW<«« >»»TRAVELTIME THRU SUBAREA<«« UPSTREAM NODE ELEVATION = 340.00 DOWNSTREAM NODE ELEVATION = 304.70 CHANNEL LENGTH THRU SUBAREA(FEET) = 435.00 CHANNEL SLOPE = .0811 CHANNEL BASE(FEET) = 25.00 "Z" FACTOR = 5.000 MANNING'S FACTOR = .030 MAXIMUM DEPTH(FEET) = 10.00 CHANNEL FLOW THRU SUBAREA(CFS) = 1.51 FLOW VELOCITY(FEET/SEC) = 1.71 FLOW DEPTH(FEET) = .04 TRAVEL TIME(MIN.) = 4.25 TC(MIN.) = 15.54 **************************************************************************** FLOW PROCESS FROM NODE 22.00 TO NODE 23.00 IS CODE = 8 >»»ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<«« 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.424 SOIL CLASSIFICATION IS "D" RURAL DEVELOPMENT RUNOFF COEFFICIENT = .4500 SUBAREA AREA(ACRES) = 2.20 SUBAREA RUNOFF(CFS) = 3.39 TOTAL AREA(ACRES) = 3.00 TOTAL RUNOFF(CFS) = 4.90 TC(MIN) = 15.54 ******************* FLOW PROCESS FROM NODE 23.00 TO NODE 24.00 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 4.8 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 13.2 UPSTREAM NODE ELEVATION = 304.70 DOWNSTREAM NODE ELEVATION = 299.10 FLOWLENGTH(FEET) = 63.00 MANNING'S N = .012 ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = PIPEFLOW THRU SUBAREA(GFS) = 4.90 TRAVEL TIME(MIN.) = .08 TC(MIN.) = 15.62 ***************************************************************•) FLOW PROCESS FROM NODE 24.00 TO NODE 25.00 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 7.8 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 6.6 UPSTREAM NODE ELEVATION = 299.10 DOWNSTREAM NODE ELEVATION = 297.70 FLOWLENGTH(FEET) = 105.00 MANNING'S N = .012 ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPEFLOW THRU SUBAREA(CFS) = 4.90 TRAVEL TIME(MIN.) = .26 TC(MIN.) = 15.88 ****************************************************************************** FLOW PROCESS FROM NODE 24.00 TO NODE 25.00 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.) = 15.88 RAINFALL INTENSITY(INCH/HR) = 3.38 TOTAL STREAM AREA(ACRES) = 3.00 PEAK FLOW RATE(CFS) AT CONFLUENCE = 4.90 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 20.90 7.64 5.410 8.90 2 4.90 15.88 3.376 3.00 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 23.96 7.64 5.410 2 17.94 15.88 3.376 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 23.96 Tc(MIN.) = 7.64 TOTAL AREA(ACRES) = 11.90 = =:=========== ============3= ====:s=s:========== = :==; s= ==== = = = = =====:r= =:======= =s=:=;===== = = ===:= END OF STUDY SUMMARY: PEAK FLOW RATE(CFS) = 23.96 Tc(MIN.) = 7.64 TOTAL AREA(ACRES) = 11.90 END OF RATIONAL METHOD ANALYSIS V LA COUNTY PUBLIC WORKS STORM DRAIN ANALYSIS (INPUT) REPT: PC/RD4412.1 DATE: 12/09/98 PAGE 1 PROJECT: CARNATION PROPERTY ""DESIGNER: 4«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 1 267.00 2 2 26.3 26.3 258.71 265.00 293.70 0.00 24. 0. 3 0.00 0.00 0.05 1 3 0 0 45. 0. 0. 4.00 0.012 2 3 24.0 24.0 203.03 294.03 296.42 0.00 24. 0. 3 0.00 0.00 0.05 0400 55. 0. 0. 4.00 0.012 2 4 24.0 24.0 91.01 296.75 297.40 0.00 24. 0. 3 0.00 0.00 0.05 0 5 7 0 0. 90. 0. 4.00 0.012 2 5 4.9 4.9 105.00 297.70 299.05 0.00 24. 0. 3 0.00 0.00 0.05 0 6 0 0 45. 0. 0. 4.00 O.C12 2 6 4.9 4.9 63.21 299.38 304.74 0.00 24. 0. 1 0.00 0.20 0.00 0 0 0 0 0. 0. 0. 0.00 0.012 2 7 20.9 20.9 108.00 297.70 320.20 0.00 18. 0. 3 0.00 0.00 0.05 5 0 0 30. 0. 0. 4.00 0.012 2 8 20.9 20.9 123.00 320.20 321.40 0.00 18. 0. 3 0.00 0.00 0.05 0 9 0 0 10. 0. 0. 4.00 0.012 2 9 15.5 15.5 56.00 321.40 322.00 0.00 18. 0. 1 0.00 0.20 0.00 0 0 0 0 0. 0. 0. 0.00 0.012 LA COUNTY PUBLIC WORKS STORM DRAIN ANALYSIS REPT: PC/RD4412.2 DATE: 12/09/98 PAGE 1 PROJECT: CARNATION PROPERTY "DESIGNER: LINE Q D W DN DC FLOW SF-FULL VI V 2 FL 1 FL 2 HG 1 HG 2 D 1 . NO (CFS) (IN) (IN) (FT) (FT) TYPE (FT/FT) (FPS) (FPS) (FT) (FT) CALC CALC (FT) D 2 TW TW (FT) CALC CK REMARKS 1 HYDRAULIC GRADE LINE CONTROL = 267.00 2 26.3 24 0 0.78 1.79 PART 0.01152 23.2 8.9 265.00 293.70 265.78 295.49 0.78 1.79 0.00 0.00 X = 0.00 X(N) = 224.25 3 24.0 24 0 1.49 1.73 FULL 0.00959 7.6 7.6 294.03 296.42 296.54 298.49 2.51 2.07 0.00 0.00 4 24.0 24 0 2.00 1.73 FULL 0.00959 7.6 7.6 296.75 297.40 299.26 300.14 2.51 2.74 0.00 0.00 5 4.9 24 0 0.57 0.78 FULL 0.00040 1.6 1.6 297.70 299.05 301.87 301.92 4.17 2.87 0.00 0.00 6 4.9 24 0 0.35 0.78 SEAL 0.00040 1.6 4.3 299.38 304.74 301.94 305.52 2.56 0.78 305.87 0.00 HYD JUMP X = 6.61 X(N) = 0.00 X(J) = 12.43 F(J) = 1.96 D(BJ) = 0.37 D (AJ) = 1.47 5 HYDRAULIC GRADE LINE CONTROL = 301.00 7 20.9 18 0 0.66 1.47 PART 0.03373 27.3 11.9 297.70 320.20 298.37 321.67 0.67 1.47 0.00 0.00 8 20.9 18 0 1.50 1.47 FULL 0.03373 11.8 11.8 320.20 321.40 322.27 326.43 2.07 5.03 0.00 0.00 9 15.5 18 0 1.50 1.41 FULL 0.01855 8.?321.40 322.00 328.42 329.46 7.02 7.46 330.89 0.00 VI, FL 1, D 1 AND HG 1 REFER TO DOWNSTREAM END V 2, FL 2, D 2 AND HG 2 REFER TO UPSTREAM END X - DISTANCE IN FEET FROM DOWNSTREAM END TO POINT WHERE HG INTERSECTS SOFFIT IN SEAL CONDITION X(N) - DISTANCE IN FEET FROM DOWNSTREAM END TO POINT WHERE WATER SURFACE REACHES NORMAL DEPTH BY EITHER DRAWDOWN OR BACKWATER X(J) - DISTANCE IN FEET FROM DOWNSTREAM END TO POINT WHERE HYDRAULIC JUMP OCCURS IN LINE F(J) - THE COMPUTED FORCE AT THE HYDRAULIC JUMP D(BJ) - DEPTH OF WATER BEFORE THE HYDRAULIC JUMP (UPSTREAM SIDE) D(AJ) - DEPTH OF WATER AFTER THE HYDRAULIC JUMP (DOWNSTREAM SIDE) SEAL INDICATES FLOW CHANGES FROM PART TO FULL OR FROM FULL TO PART HYD JUMP INDICATES THAT FLOW CHANGES FROM SUPERCRITICAL TO SUBCRITICAL THROUGH A HYDRAULIC JUMP HJ 9 UJT INDICATES THAT HYDRAULIC JUMP OCCURS AT THE JUNCTION AT THE UPSTREAM END OF THE LINE HJ ® DJT INDICATES THAT HYDRAULIC JUMP OCCURS AT THE JUNCTION AT THE DOWNSTREAM END OF THE LINE EOJ 12/ 8/1998 10:56 VI Carnation Property Hydrology Report 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: 4 Intensity-Duration Design Chart + Nomograph for Determination of Time of Concentration (Tc) for Natural Watersheds 4 Urban Areas Overland Time of Flow Curves * 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 support. Soils maps are also not included, as Hydrologic Soil Group "D". RA:kd :msword\h:\aes92\2308\2\hyd.doc W.0.2308-1 12/10/98