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HomeMy WebLinkAboutPUD 02-11A; LA COSTA GREENS; DRAINAGE STUDY; 2004-05-26'10 OFESS/o/V NO. 4867 Jsri Exp. 6/30/04 / (200 o-llM) F7/( #- 9 AH:kc H:\REPORTS\2352\96\2ND SUBMITTALAO2.doc W.O. 2352-96 5/26/2004 4:50 PM HUNSAKER &ASSOCIATES S A N D I E C 0, I N C. PLANNING ENGINEERING SURVEYING IRVINE DRAINAGE STUDY LOS ANGELES for RIVERSIDE SAN DIEGO LA COSTA GREENS RECREATION CENTER City of Carlsbad, California Prepared for: Real Estate Collateral Management Company do Morrow Development 1903 Wright Place Suite 180 Carlsbad, CA 92008 W.O. 2352796 May 26, 2004 Hunsaker & Associates San Diego, Inc. DAVE HAMMAR LEX WILLIMAN ALISA VIALPANDO DAN SMITH RAY MARTIN Raymond L. Martin, R.C.E. 10179 Huennekens St. Vice President San Diego CA 92121 (858) 558-4500 PH (858) 558-1414 FX www.I-IunsakerSD.com Inlo@HunsakerSD.com Drainage Study La Costa Greens - Recreation Center TABLE OF CONTENTS SECTION Chapter 1 - Executive Summary 1.1 Introduction 1.2 Vicinity Maps 1.3 Existing Condition 1.4 Proposed Project 1.5 Summary of Results 1.6 Conclusion 1.7 References Chapter 2 - Methodology & Model Development Il 2.1 City of Carlsbad Drainage Design Criteria 2.2 Rational Method Hydrologic Analysis 2.3 Storm Drain System Analysis Chapter 3 - Rational Method Hydrologic Analysis III (100-Year Developed Condition AES Model Output) Chapter 4— Hydraulic Analysis IV (StormCAD Model Output) Chapter 5 - Catch Basin Sizing V Chapter 6 - References VI 6.1 100-Year, 6-Hour Isopluvial Plan 6.2 Rainfall-Duration Design Chart 6.3 Nomograph for Determination of Time of Concentration (Tc) for Natural Watersheds 6.4 Urban Areas Overland Time of Flow Curves 6.5 Runoff Coefficients (Rational Method) 6.6 Excerpt from the "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens Phase I Neighborhoods 1.08 -1.14" AI1:kc H:\REPORTS\2352\96\2ND SUBMITrAL\A02.doc W.O. 2352-96 5/26/2004 4:50 PM Drainage Study La Costa Greens - Recreation Center 6.7 Hydrology Exhibit 9.3 from the "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens Phase I Neighborhoods 1.08 -1.14" Chapter 7 - Hydrology Exhibits VII Exhibit 7.1 Developed Condition Hydrology Map AH:kc H:\REPORTS\2352\96\2NDSUBMITTAL\AO2.doc W.O. 2352-96 512612004 4:50 PM Drainage Study La Costa Greens - Recreation Center EXECUTIVE SUMMARY Introduction The La Costa Greens Recreation site is located at the southeast corner of the Lapis Road (South)-Alicante Road intersection in the City of Carlsbad, California. The project site is also bounded by the La Costa Greens Neighborhood 1.09 to the north, La Costa Greens Neighborhood 1.10 to the west, La Costa Greens Neighborhood 1.12 to the southeast, and Amber Lane to east. The vicinity maps below have been included to illustrate the project site's location. This drainage study will address: 100-Year Peak Flowrates for Developed Conditions Hydraulic Calculations Catch Basin Sizing Existing Condition The La Costa Greens Recreation site is part of the La Costa Greens development in the City of Carlsbad, California. Located in the Batiquitos watershed, the site consists of primarily undisturbed terrain covered with natural vegetation with portions being mass-graded, as shown on Drawing No. 397-2A. Natural runoff from the undeveloped site flows in a westerly direction to an unnamed tributary of San Marcos Creek, which then flows in a southerly direction along the site boundary of the La Costa Greens Golf Course, west of the Phase I development area. All the runoff eventually drains under Alga Road via three 96" RCP culverts and discharges into San Marcos Creek towards Batiquitos Lagoon. AHkc H:REPORTS2352\96\2ND SUBMIT1ALAO2.doc W.O. 2352-96 512612004 4:50 PM \ Drainage Study La Costa Greens - Recreation Center The project site does not receive any offsite runoff from the neighboring developments. Existing condition peak flowrates, listed on Table I below, were obtained from the "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens Phase I Neighborhoods 1.08 -1.14" prepared by Hunsaker & Associates San Diego, Inc. on August 4, 2003. Refer to Chapter 6 for excerpts from the previously mentioned study. TABLE I Summary of Existing Condition Hydrologic Results Node ID* Node ID Drainage 100-Year Time of (Per Exist. Study) (Per Dev. Study) Area Peak Concentration (acres) Flow (cfs) (mm) 353 102 8.3 13.6 15.5 354k 103 8.3 13.6 15.5 * Based on "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens Phase / Neighborhoods 1.08 -1.14 ' Based on this study + At Node 354, the hydrologic results depicted in Table 1 do not include the data from street flow. Only data from the recreation center site is included. Proposed Project The construction of the La Costa Greens Recreation Center site will include a clubhouse with a pool and its associated offices and storage rooms, walkways, internal sub-drain system, and open space areas. Also, a pond will be graded and constructed southwest of the clubhouse and pool area. Runoff from the developed site area will be collected and conveyed via a proposed Type 'G-1' catch basin and an 18" RCP pipe located on Lapis Road (South) at Station 10+64.52. The proposed storm drain system will tie to an existing Type 'B-I' curb inlet also located on Lapis Road (South) at Station 10+64.52 per Drawing No. 397-2. The proposed and existing storm drain systems are visually depicted on the Hydrology Exhibit 7.1 located in the back pocket of this report (see Chapter 7). All runoff from developed conditions of the proposed site will eventually drain to the I unnamed tributary of San Marcos Creek via the previously mentioned existing storm drain system per Drawing No. 397-2. I Summary of Results For the Rational Method Analysis, a runoff coefficient of 0.45 was used for I undisturbed, natural terrain and a runoff coefficient of 0.85 was used for the clubhouse and pool area, corresponding to areas that are 80% impervious. All runoff coefficients are based on the "San Diego County Hydrology Manual'. AH:kc H:'REPORTS\2352\96\2ND SUBMITTALO2.dOC W.O. 2352.96 5126/2004 4:50 PM Drainage Study La Costa Greens - Recreation Center Developed condition peak flowrates, listed on Table 2 below, are based on the AES- 99 computer program and criteria set forth in the City of Carlsbad's Drainage Design Criteria (see Chapter 2 for methodology and model development and Chapter 3 for the AES model output). Watershed delineations are visually depicted on the Hydrology Exhibit 7.1 (see back pocket in Chapter 7). TABLE 2 Summary of Developed Condition Hydrologic Results Node ID* Node ID Drainage 100-Year Time of (Per Exist. Study) (Per Dev. Study) Area Peak Concentration (acres) Flow (cfs) (mm) 353 102 7.3 12.9 12.5 354+ 103 8.2 16.2 12.5 * Based on "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens Phase I Neighborhoods 1.08 -1.14 A Based on this study + At Node 354, the hydrologic results depicted in Table I do not include the data from street flow. Only data from the recreation center site is included. A 2.6-cfs increment at Node 103 occurs due to the fact that when the existing condition hydrologic analysis was performed, the subarea was assumed to be a future residential development; thus, the runoff coefficient was lower than the one used in this study. However, the 2.6-cfs increment does not affect the hydraulics of the existing storm drain system. For the hydraulic portion of this report, all pipes were analyzed with the StormCAD software. Using a starting downstream water surface elevation at the discharge location, the program calculated the hydraulic grade line for the RCP storm drain system (see Chapter 4 for StormCAD model output). One Type 'G-1' catch basin was sized to ensure that it is capable of handling 100- year peak flows. The ponding depth at the catch basin was also checked to ensure that the peak runoff will not spill over the berm and overflow onto Lapis Road (see Chapter 5 for catch basin sizing). Conclusion I Based on the calculations completed herein, the storm drain system will be able to function as designed and handle the flows generated from the La Costa Greens Recreation Center site. Drainage design, including watershed delineation and storm I drain sizing, results in no adverse impact to downstream property owners. Construction of the storm drain improvements as shown herein will safely collect and convey peak discharge through the development. I AH:kc H:'REPORTS'2352\962ND SUBMirrAL02.d0c W.O. 2352-96 5/2612004 4:50 PM Drainage Study La Costa Greens - Recreation Center References "San Diego County Hydrology Manual". Department of Public Works - Flood Control Division. County of San Diego, California. Revised April 1993. "City of San Diego Regional Standard Drawings". Section D - Drainage Systems. Updated March 2000. "Standards for Design and Construction of Public Works Improvements in the City of Carlsbad"; City of Carlsbad, California; April 1993. "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens - Phase I Neighborhoods 1.08 -1.14"; Hunsaker & Associates San Diego, Inc.; August 4, 2003. Drawing No. 397-2A "Grading Plans for La Costa Greens Phase I"; O'Day Consultants; January 16, 2003. Drawing No. 397-2 "Improvement Plans for La Costa Greens Phase 1'; Hunsaker & Associates San Diego, Inc.; January 21, 2004. AH:kc H:\REP0RTS\2352\96\2ND SUBMITFAL02.d0c W.O. 2352-96 5/26/2004 4:50 PM II I Drainage Study La Costa Greens - Recreation Center CHAPTER 2 METHODOLOGY & MODEL DEVELOPMENT I 2.1 - City of Carlsbad Drainage Design Criteria AH:kc H:\REPORTS\2352\96\2ND SUBMITTAL.A02doc W.O. 2352-96 5/26/2004 4:50 PM DRAINAGE - DESIGN CRITERIA 1.• GENERAL A. All drainage design and requirements shall be in accordance with the latest City of Carlsbad Master Drainage and Storm Water Quality Management Plan and the requirements of the City Engineer and be based on full development of upstream tributary basins. B. Public drainage facilities shalt be designed to carry the ten-year six-hour storm underground, the 50-year six-hour storm between the top of curbs and the 100-year six-hour storm between the right-of-way lines. All culverts shall be designed to accommodate a 1 00-year six-hour storm. C. The use of underground storm drain systems, in addition to standard curb and gutter shall be required: When flooding or street overf'ow during 100-year six-hour storm cannot be maintained between right-of-way lines. When 1 00-year six-hour storm flow from future upstream development (as proposed in the existing General Plan) will cause damage to structures and improvements. When existing adequate drainage facilities are available for use (adjacent to proposed development). When more than one travel lane of arterial and collector streets would be obstructed by 10-year 6-hour storm water flow. Special consideration will be required for super-elevated streets. D. The use of underground storm drain systems may be required: When the water level in streets at the design storm is within 1" of top of curb. When velocity of water in streets exceeds 11 FPS. When the water travels more than 1,000' over land. E. The type of drainage facility shall be selected on the basis of physical and cultural adaptability to the proposed land use. Open channels may be considered in lieu of underground systems when the peak flow exceeds the capacity of a 48" diameter RCP. Fencing of open channels may be required as determined by the City Engineer. F. Permanent drainage facilities and right-of-way, including access, shall be provided from development to point of satisfactory disposal. 17 G. Storm Drains constructed at a depth of 15' or greater measured from finish grade to the top of pipe or structure shall be considered deep storm drains* tind should be avoided if at all possible. When required, special design consideration will be required to the satisfaction of the City Engineer. Factors considered in the design will include: I 1) Oversized specially designed access holes/air shafts Line encasements Oversizing lines I - 4) Increased easement requirements for maintenance access 5) Water-tight joints I 6) Additional thickness of storm drain The project designer should meet with the planchecker prior to initiation of design to review design parameters. I - H. Concentrated drainage from lots or areas greater than 0.5 acres shall not be - discharged to City streets unless specifically approved by the City Engineer. Diversion of drainage from natural or existing basins is discouraged. 2. HYDROLOGY A. Off site, use a blue-line print of the latest edition City 400-scale topographic mapping. Show existing culverts, cross-gutters and drainage courses based on field review. Indicate the direction of flow; clearly delineate each drainage basin showing the area and discharge and the point of concentration. B., On site, use the grading plan. If grading is not proposed, then use a 100-scale plan or greater enlargement. Show all proposed and existing drainage facilities and drainage courses. Indicate the direction of flow. Clearly delineate each drainage basin showing the area and discharge and the point of concentration. C. Use the charts in the San Diego County Hydrology Manual for finding the 'Ta" and ultl. For small areas, a five minute 'Ta" may be utilized with prior approval of the City Engineer. I D. Use the existing or ultimate development, whbhever gives the highest "C" factor. E. Use the rational formula Q = CIA for watersheds less than 0.5 square mile unless I an alternate method is approved by the City Engineer. For watersheds in excess of 0.5 square mile, the method of analysis shall be approved by the City Engineer prior - to submitting calculations. I 3. HYDRAULICS. A. Street - provide: 18 Depth of gutter flow calculation. Inlet calculations. Show gutter flow Q, inlet Q, and bypass Q on a plan of the street. B. Storm Drain Pipes and Open Channels - provide: Hydraulic loss calculations for: entrance, friction, junction, access holes, bends, angles, reduction and enlargement. Analyze existing conditions upstream and downstream from proposed system, to be determined by the City Engineer on a case-by-case basis. Calculate critical depth and normal depth for open channel flow conditions. Design for non-silting velocity of 4 FPS in a two-year frequency storm unless otherwise approved by the City Engineer. All pipes and outlets shall show HGL, velocity and Q value(s) for which the storm drain is designed to discharge. Confluence angles shall be maintained between 450 and 900 from the main upstream flow. Flows shall not oppose main line flows. 4. INLETS Curb inlets at a sump condition should be designated for two US per lineal foot of opening when headwater may rise to the top of curb. Curb inlets on a continuous grade should be designed based on the following equation: Q=O.7L(a+y)3"2 Where: y = depth of flow in approach gutter in feet a = depth of depression of flow line at inlet in feet L = length of clear opening in feet (maximum 30 feet) Q = flow in CFS, use 50-year design storm minimum Grated inlets should be avoided when possible. When necessary, the design should be based on the Bureau of Public Roads Nomographs (now known as the Federal Highway Administration). All grated inlets shall be bicycle proof. All catch basins shall have an access hole in the top unless access through the grate section satisfactory to the City Engineer is provided. Catch basins/curb inlets shall be located so as to eliminate, whenever possible, cross gutters. Catch basins/curb inlets shall not be located within 5' of any curb return or driveway. - 19 5 F. Minimum connector pipe for public drainage systems shall be1.". G. Flow through inlets may be used when pipe size is 24" or less and open channel flow characteristics exist. STORM DRAINS Minimum pipe slope shall be .005 (.5%) unless otherwise approved by the City Engineer. Minimum storm drain, within public right-of-way, size shall be 18" diameter. Provide cleanouts at 300' maximum spacing and at angle points and at breaks in grade greater than 100. For pipes 48" in diameter and larger, a maximum spacing of 500' may be used. The material for storm drains shall be reinforced concrete pipe or asbestos cement pipe designed in conformance with San Diego County Flood Control District's design criteria, as modified by Carlsbad Standard Specifications. Corrugated steel pipe shall not be used. Plastic/rubber collars shall be prohibited. Horizontal and vertical curve design shall conform to manufacturer recommended specifications. F The pipe invert elevations, slope, and pipe profile line shall be delineated on the mylar of the improvement plans. The strength classification of any pipe shall be shown on the plans. Minimum D-load for RCP shall be 1350 in all City streets or future rights-of-way. ACP shall have 2.0 times the minimum D-load required for RCP. Minimum D-load for depths less than 2', if allowed, shall be 2000 or greater. G. For all drainage designs not covered in these Standards, the current San Diego County Hydrology and Design and Procedure Manual shall be used. H. For storm drain discharging into unprotected or natural channel, proper energy dissipation measures shall be installed to prevent damage to the channel or erosion. I. The use of detention basins to even out storm peaks and reduce piping is permitted with substantiating engineering calculation and proper maintenance agreements. J. Desiltation measures for silt caused by development shall be provided and cleaned regularly during the rainy s9as0n (Octr'ber 1st to April 15th) and after rr\aior rainfall as required by the City Engineer or his designated representative. 20 Adequate storage capacity as determined by the City Engineer shall be maintained at all times. Protection of downstream or adjacent properties from incremental flows (caused by change from an undeveloped to a developed site) shall be provided. Such flows shall not be concentrated and directed across unprotected adjacent properties unless an easement and storm drains or channels to contain flows are provided. Unprotected downstream channels shall have erosion and grade control structures installed to prevent degradation, erosion, alteration or downcutting of the channel banks. Storm drain pipes designed for flow meeting or exceeding 20 feet per second will require additional cover over invert reinforcing steel as approved by the City Engineer. Storm drain pipe under pressure flow for the design storm, i.e., HGL above the soffit of the pipe, shall meet the requirements of ASTM C76, C361, C443 for water-tight joints in the sections of pipe calculated to be under pressure. 0. An all weather access road from a paved public right-of-way shall be constructed to all drainage and utility improvements. The following design parameters are required: Maximum grade 14%, 15 MPH speed, gated entry, minimum paved width 12 feet, 38' minimum radius, paving shall be a minimum of 4" AC over 4" Class II AB, turnaround required if over 300'. Work areas should be provided as approved by the plan checker. Access roads should be shown on the tentative project approval to ensure adequate environmental review. P. Engineers are encouraged to gravity drain all lots to the street without use of a yard drain system. Where this is not possible yard drains should exit through the curb face in conformance with SDRSD D-27. 21 MODIFICATIONS TO SAN DIEGO REGIONAL STANDARD DRAWINGS The Standard Drawings for the City of Carlsbad shall be comprised of the current edition of the San Diego Area Regional Standard Drawings (SDRSD) as published by the San Diego Department of Transportation and as modified by the additions and substitutions listed below and the City of Carlsbad Supplemental Standards attached hereto. Modifications to the San Diego Area Regional Standard Drawings Concrete requirement within public right-of-way shall be 560-C-3250 minimum for all Improvements. D-2 Enlarge curb inlet top to width of sidewalk (not to exceed 5'6") by length of inlet Including wings. Existing reinforcing steel shall be extended across enlarged top to clear distances shown. D-20 Delete. D-27 Add: A maximum of three (3) combined outlets in lieu .of Std. D-25. D-40 Add: 'T' dimension shall be a minimum of three (3) times size of rip rap. D-70 Minimum bottom width shall be 6' to facilitate cleaning. D-71 Minimum bottom width shall be 6' to facilitate cleaning. D-75 Delete 'Type-A" Add: 6" x 6" x #10 x #10 welded wire mesh, instead of stucco netting. E-1 Delete direct burial foundation. Add: The light standard shall be prestressed concrete round pole. 0-3 Delete. 0-5 . Add: Note 4. Tack coat shall be applied between dike and existing asphalt concrete surface as specified in Section 302-5.4 SSPWC. 0-6 Type B-i and B-2 curb heights shall be 8 inches with 2:1 batter. G-1 1 Add: Remove curb/gutter and sidewalk from score-mark to score-mark or from joint-to-joint or approved combination. 0-12 Add: smooth trowel flow line (typical) 7-1/2' thick. 0-13 Add:, smooth trowel flow line (typical). 29 Drainage Study La Costa Greens - Recreation Center CHAPTER 2 METHODOLOGY & MODEL DEVELOPMENT 2.2 - Rational Method Hydrologic Analysis AH:kc H:\REPORTS\2352\96'2ND SUBMITTAL'A02.doc W.O. 2352-96 5/2612004 4:50 PM Drainage Study La Costa Greens - Recreation Center Rational Method Hydrology Analysis Computer Software Package - AES-99 Design Storm - 100-Year Return Interval Land Use - Commercial in Developed Areas Soil Type - Hydrologic soil group D was assumed for all areas. Group D soils have very slow infiltration rates when thoroughly wetted. Consisting chiefly of clay soils with a high swelling potential, soils with a high permanent water table, soils with clay pan or clay layer at or near the surface, and shallow soils over nearly impervious materials, Group D soils have a very slow rate of water transmission. Runoff Coefficient.— In accordance with the County of San Diego standards, I developed areas (commercial) were designated a runoff coefficient of 0.85 while natural areas were designated a runoff coefficient of 0.45. I Method of Analysis - The Rational Method is the most widely used hydrologic model for estimating peak runoff rates. Applied to small urban and semi-urban areas with drainage areas less than 0.5 square miles, the Rational Method relates storm rainfall I intensity, a runoff coefficient, and drainage area to peak runoff rate. This relationship is expressed by the equation: I Q= CIA, where: Q = The peak runoff rate in cubic feet per second at the point of analysis. I C = A runoff coefficient representing the area - averaged ratio of runoff to rainfall intensity. = The time-averaged rainfall intensity in inches per hour corresponding to the I time of concentration. A = The drainage basin area in acres. I To perform a node-link study, the total watershed area is divided into subareas which discharge at designated nodes. The procedure for the subarea summation model is as follows: Subdivide the watershed into an initial subarea (generally 1 lot) and subsequent subareas, which are generally less than 10 acres in size. Assign upstream and downstream node numbers to each subarea. Estimate an initial Tc by using the appropriate nomograph or overland flow velocity estimation. Using the initial T, determine the corresponding values of I. Then Q = C I A. Using 0, 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. AHah H:\REPORTS\2352X96\2NDSUBMITTAL\AO2.doc W.O. 2352-11296 5/26/2004 3:20 PM I Drainage Study La Costa Greens - Recreation Center I Then, repeat the calculation for Q based on the revised intensity (which is a I function of the revised time of concentration) I The nodes are joined together by links, which may be street gutter flows, drainage swales, drainage ditches, pipe flow, or various channel flows. The AES-99 computer subarea menu is as follows: I SUBAREA HYDROLOGIC PROCESS 1. Confluence analysis at node. I 2. Initial subarea analysis (including time of concentration calculation). 3. Pipeflow travel time (computer estimated). I 4. Pipeflow travel time (user specified). 5. Trapezoidal channel travel time. I 6. Street flow analysis through subarea. 7. User - specified information at node. 1 8. Addition of subarea runoff to main line. 9. V-gutter flow through area. I 10. Copy main stream data to memory bank 11. Confluence main stream data with a memory bank 1 12. Clear a memory bank I At the confluence point of two or more basins, the following procedure is used to combine peak flow rates to account for differences in the basin's times of concentration. This adjustment is based on the assumption that each basin's I 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 I 2. If the collection streams have different times of concentration, the smaller of the tributary Q values may be adjusted as follows: I a. 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 I ratio of rainfall intensities. Qp = Q. + Qb (la/lb) T = Ta I I AHafl H:\REP0RTS'2352\96\2ND SUBMITTAL\.A02.d0c W.O. 2352-11296 5126/2004 3:20 PM Drainage Study La Costa Greens - Recreation Center I b. In some cases, the collection stream with the shorter time of concentration I has the larger Q. Then the smaller Q is adjusted by a ratio of the T values. Qp = QbQa (TbITa) Tp = Tb AH:h H\REPQRTS\2352\96\2N0 SUBMITTAL'O2.doc WO. 2352-11296 512612004 3:20 PM Drainage Study La Costa Greens - Recreation Center CHAPTER 2 METHODOLOGY & MODEL DEVELOPMENT 2.3 - Storm Drain System Analysis AH:kc H:\REPORTS\2352\96\2ND SUBMIITAL'A02.doc W.O. 2352-96 5/26/2004 4:50 PM Drainage Study La Costa Greens - Recreation Center Storm Drain Hydraulic Analysis Computer Software - StormCAD I Design Storm - 100-Year Return Interval Storm drain systems in this analysis were sized to prevent street flooding and to I - predict outlet velocities to receiving channels. The StormCAD computer program, developed by Haested Methods, was used to predict hydraulic grade lines, pipe flow I travel times, and velocities in the storm drain systems. Required input includes the peak flowrate at each inlet, upstream and downstream inverts, pipe lengths, and rim elevations. Flow calculations are valid for both pressure and varied flow situations, including hydraulic jumps, backwater, and drawdown curves. The gravity network solution is solved using a numerical model that utilizes both the direct step and standard step gradually varied flow methods. Junction losses are modeled using the standard method, which calculates structure headloss based on the structure's exit velocity (velocity at the upstream end of the downstream pipe). The exit velocity head is multiplied by a user-entered coefficient to determine the loss according to the following formula: Hs =K*V02 /2g Where Hs = structure headloss (ft.) K = headloss coefficient V0 = exit pipe velocity (Ws) G = gravitational acceleration (ft/S2) Typical headloss coefficients used for the standard method range from 0.5 to 1.0 depending on the number of pipes meeting at the junction and the confluence angle. For a trunkline only with no bend at the junction, a headloss coefficient of 0.5 is selected. For three or more entrance lines confluencing at a junction, a value of 1.0 is selected. AHah H:\REPORTS2352\96\2ND SUBMFflAL'.A02.doc W.O. 2352-11296 5/2612504 3:20 PM III Drainage Study La Costa Greens - Recreation Center CHAPTER 3 RATIONAL METHOD HYDROLOGIC ANALYSIS I 100-Year Developed Condition (AES Model Output) I AH:kc H:\REPORTS\2352\96\2ND SUBMlTTAL02doc W.O. 2352-96 5/26/2004 4:50 PM **************************************************************************** RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-99 Advanced Engineering Software (aes) Ver. 1.5A Release Date: 01/01/99 License ID 1239 Analysis prepared by: Hunsaker & Associates - San Diego, Inc. 10179 Huennekens Street San Diego, Ca. 92121 (858) 558-4500 * * * * * * * * * * * * * * * * * * * * * * * * * * DESCRIPTION OF STUDY * * * * * * * * * * * * * * * * * * * * * * * * * * * LA COSTA GREENS - RECREATION CENTER * * 100-YEAR DEVELOPED CONDITION HYDROLOGY ANALYSIS * * W.O.# 2352-96 * FILE NAME: H:\AES99\2352\96\DEV100.DAT TIME/DATE OF STUDY: 17: 3 5/25/2004 ---------------------------------------------------------------------------- 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 = 0.90 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED + --------------------------------------------------------------------------+ I I BEGIN RECREATION CENTER BASIN (NODE SERIES 100) + --------------------------------------------------------------------------+ **************************************************************************** FLOW PROCESS FROM NODE 101.00 TO NODE 102.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< *USER SPECIFIED (SUBAREA) RURAL DEVELOPMENT RUNOFF COEFFICIENT = .4500 NATURAL WATERSHED NOMOGRAPH TIME OF CONCENTRATION (APPENDIX X-A) WITH 10-MINUTES ADDED = 12.49(MINUTES) INITIAL SUBAREA FLOW-LENGTH = 755.00 UPSTREAM ELEVATION = 320.00 DOWNSTREAM ELEVATION = 185.00 ELEVATION DIFFERENCE = 135.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.941 SUBAREA RUNOFF(CFS) = 12.89 TOTAL AREA(ACRES) = 7.27 TOTAL RUNOFF(CFS) = 12.89 ** *** *** * ***************** * ************************************* ** ********* * FLOW PROCESS FROM NODE 102.00 TO NODE 103.00 Is CODE = 4 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<<<<< >>>>>USING USER-SPECIFIED PIPESIZE<<<<< - DEPTH OF FLOW IN 18.0 INCH PIPE IS 7.4 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 19.0 UPSTREAM NODE ELEVATION = 189.70 DOWNSTREAM NODE ELEVATION = 185.33 FLOWLENGTH(FEET) = 32.16 MANNING'S N = 0.013 GIVEN PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPEFLOW THRU SUBAREA(CFS) = 12.89 TRAVEL TIME(MIN.) = 0.03 TC(MIN.) = 12.52 **************************************************************************** FLOW PROCESS FROM NODE 103.00 TO NODE 103.00 IS CODE ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = 12.52 RAINFALL INTENSITY(INCH/HR) = 3.94 TOTAL STREAM AREA(ACRES) = 7.27 PEAK FLOW RATE(CFS) AT CONFLUENCE = 12.89 **************************************************************************** FLOW PROCESS FROM NODE 104.00 TO NODE 105.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< *USER SPECIFIED (SUBAREA) COMMERCIAL DEVELOPMENT RUNOFF COEFFICIENT = .8500 INITIAL SUBAREA FLOW-LENGTH = 485.00 UPSTREAM ELEVATION = 235.00 DOWNSTREAM ELEVATION = 215.00 ELEVATION DIFFERENCE = 20.00 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 6.180 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.205 SUBAREA RUNOFF(CFS) = 5.06 TOTAL AREA(ACRES) = 0.96 TOTAL RUNOFF(CFS) = 5.06 FLOW PROCESS FROM NODE 105.00 TO NODE 103.00 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 4.9 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 12.8 UPSTREAM NODE ELEVATION = 204.00 DOWNSTREAM NODE ELEVATION = 186.00 FLOWLENGTH(FEET) = 190.61 MANNING'S N = 0.013 ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = PIPEFLOW THRU SUBAREA(CFS) = 5.06 TRAVEL TIME(MIN.) = 0.25 TC(MIN.) = 6.43 **************************************************************************** FLOW PROCESS FROM NODE 103.00 TO NODE 103.00 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.) = 6.43 RAINFALL INTENSITY(INCH/HR) = 6.05 TOTAL STREAM AREA(ACRES) = 0.96 PEAK FLOW RATE(CFS) AT CONFLUENCE = 5.06 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 12.89 12.52 3.935 7.27 2 5.06 6.43 6.050 0.96 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 13.45 6.43 6.050 2 16.19 12.52 3.935 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 16.19 Tc(MIN.) = 12.52 TOTAL AREA(ACRES) = 8.23 + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + END RECREATION CENTER BASIN (NODE SERIES 100) I -------- +-END-OF-STUDY-SUMMARY: END OF STUDY SUMMARY: PEAK FLOW RATE(CFS) = 16.19 Tc(MIN.) = 12.52 I TOTAL AREA(ACRES) = 8.23 END OF RATIONAL METHOD ANALYSIS I1 Iv I Drainage Study La Costa Greens - Recreation Center I i CHAPTER 4 HYDRAULIC ANALYSIS I (STORMCAD MODEL OUTPUT) I AI1:kc H:\REPORTS2352\96\2NO SUBMIflAL\A02.doc W.O. 2352-96 5126/2004 4:50 PM RECREATION CENTER SITE Scenario: LA COSTA GREENS - RECREATION CENTER NOTE: NODE ID FR ................. REVISED HYDRAULIC STUDY FOR LA COSTA GREENS PHASE I NEIGHBORHOODS 1.08 -1.14. FOR STORM DRAIN ELEMENTS DESCRIBED AS EXISTING REFER TO DRAWING NO. 397-2. Title: LA COSTA GREENS - RECREATION CENTER Project Engineer: Anabella Hedman h:\stormcad\2352\96\2nd submittal\rec center.stm Hunsaker & Associates - San Diego, Inc. StormCAD v5.5 [5.5003] 05/26/04 03:50:01 PM © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 - - - - - - - - - - - - - - - - - - - Scenario: LA COSTA GREENS - RECREATION CENTER Combined Pipe\Node Report Label U/S 0/S U/S 0/S U/S D/S Pipe Material Mannings Length Slope Flow Max HGL HGL Velocity Velocity Node Node Ground Ground Invert Invert Size 'n' (if) (%) (cfs) Flow In Out In Out Elevation Elevation Elevation Elevation (cfs) (if) (if) (ft/s) (if/s) (if) (if) (if) (if) P-1 GB 102 EX-l-103 194.00 194.36 189.70 185.33 18 inch Concret 0.013 32.16 13.59 12.89 38.72 192.61 192.13 7.29 7.29 EX-P-2 EX-l-103 EX-CO-1 194.36 194.15 185.00 183.10 18 inch ConcretE 0.013 37.25 5.10 17.69 23.72 191.35 190.29 10.01 10.01 EX-P- EX-1-1 EX-CO-1 194.28 194.15 184.20 183.10 18 inch ConcretE 0.013 11.25 9.78 5.81 32.84 190.32 190.29 3.29 3.29 EX-P-.4EX-CO-2 EX-CO-1 202.96 194.15 184.83 180.43 54 inch ConcretE 0.013 146.00 3.01 214.68 341.36 192.03 190.29 13.50 13.50 Title: LA COSTA GREENS - RECREATION CENTER Project Engineer: Anabella Hedman h:\stormcad\2352\96\rec center.stm Hunsaker & Associates - San Diego, Inc. StormCAD v5.5 [55003] 05/26/04 09:52:25 AM © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 - - - - - - - - - - - - - - - - - - - Profile Scenario: LA COSTA GREENS - RECREATION CENTER LA COSTA GREENS - RECREATION CENTER REC CENTER STORM DRAIN Label: EX-I-103 - Rim: 194.36 ft Sump: 185.00 ft Label: CB 102 Rim: 194.00 ft Sump: 189.70 ft Label: P-i Up. Invert: 189.70 ft Dn. Invert: 185.33 ft L: 32.16 ft Size: 18 inch S: 13.59 % Label: EX-CO-1 \ / Rim: 194.15 ft / Sump: 180.10 ft / - Label: EX-I-1 Rim: 194.28 ft Sump: 184.20 ft - / \ \S\ \\\ \ Si Label: EX-P-3 Up. Invert: 184.2 .7' Dn. Invert: 183.1 L: 11.25 ft Size: 18 inch 200.00 195.00 190.00 Elevation (ft) 185.00 ft ft Project Engineer: Anabella Hedman StormCAD v5.5 [5.5003] Page 1 of 1 S: 9.78 % Label: EX-P-2 Up. Invert: 185.00 ft 180.00 Dn. Invert: 183.10 t 0+00 0+50 1+00 1+50 Size: 18 inch S: 5.10 % Station (ft) Title: LA COSTA GREENS - RECREATION CENTER h:\stormcad\2352\96\rec center.stm Hunsaker & Associates - San Diego, Inc. 05/26/04 09:52:33 AM © Haestad Methods, inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 LIN Drainage Study La Costa Greens - Recreation Center I CHAPTER 5 CATCH BASIN SIZING AH:ah H:\REPORTS\2352\96\2ND SU8MIUALO2.doc W.O. 2352-11296 5/26/2004 3:20 PM TYPE "G" CATCH BASIN PER SDRSD D-8 LA COSTA GREENS - RECREATION CENTER 4LXTiTAi Design Flow, Q = 12.89 cfs Per SDRSD D-1 5, "Drainage Structure Grate", the single grate dimensions are: Length, L = T - 4" = 3.33 ft Width, W = 1,-111 '8 = 1.97 ft WEIR EQUATION: Q = CLH3/2 where: C = Weir Coefficient 3.0 when H0.5feet = 3.3 when H >= 1.0 feet L = Length of the Weir (feet) H = Water Height over Weir (feet) ORIFICE EQUATION: Q = CA(2gH)1/2 where: C = Orifice Coefficient = 0.60 A = Cross Sectional Area of Orifice (ft) g = Gravitational Constant (32.2 ft/S2) H = Water Height over Centroid of Orifice (ft) Calculations for Catch Basin Type "G" - Single "G- 1" per SDRSD D-8: Water Height (feet) Riser Box Length (feet) Riser Box Width (feet) Weir Coeff. Weir Length (feet) Orifice Coeff. Orifice Area* (ft) Weir Flow (cfs) Orifice Flow (cfs) 0.2 3.33 1.97 2.80 10.6 0.6 3.28 2.65 7.06 0.4 3.33 1.97 2.92 10.6 0.6 3.28 7.83 9.99 0.6 3.33 1.97 3.08 10.6 0.6 328 15.17 12.23 08 333 197 330 106 06 328 2503 1413 1.0 3.33 1.97 3.32 10.6 0.6 3.28 35.19 15.79 1.2 3.33 1.97 3.32 10.6 0.6 3.28 46.26 17.30 1.4 3.33 1.97 3.32 10.6 0.6 3.28 58.30 18.69 1.6 3.33 1.97 3.32 10.6 0.6 3.28 71.22 19.98 1.8 3.33 1.97 3.32 10.6 0.6 3.28 84.99 21.19 2.0 3.33 1.97 3.32 10.6 0.6 3.28 99.54 22.34 *NOTE: Assumes 50% clogging. 5/26/2004 10:19 AM 1 of 1 H:\EXCEL\2352\96\TYPE G CB.xls VI Drainage Study La Costa Greens - Recreation Center CHAPTER 6 REFERENCES 6.1 - 100-Year, 6-Hour Isopluvial Map AH:ah H:\REPORTS\235296\2ND SUBMITTAL'A02.doc WO. 2352-11296 6/26/2004 3:20 PM -- - - - - - - - --- - COUNTY OF SAN DIEGO DEPARTMENT OF FLOOD CONTROL SANITATION 100-YEAF 6-HOU PR ECIPITAT ION '20..' ISOPLUVIALS OF 100-YEAR 6-HOUR 451 PRECIP ill'ATION 1 1ETHS OF AU IC 33. 451 Prenf.d U.S. DEPARTMENfr NATIONAL. OCEANIC AND AT405I SPECIAL STUDIES BRANCH, OFFICE OF II1DR 30' II 1+5' 30' 15' 117°1151 "30' 15' 1160 Revised 1/85 APPENDIX XI-E Drainage Study La Costa Greens - Recreation Center CHAPTER 6 REFERENCES 6.2 - Rainfall-Duration Design Chart AHah H:\REPORTS\2352\962NO SU8MITTAL02.dac W.O. 2352-11296 5126/2004 320 PM — — — — — - — — — — — — — INTENSITY-DUMTL., DESIGN CHART Directions for Application: From precipitation naps determine 6 hr. and 24 hr. amounts for the selected frequency. These maps are printed in the County Hydrology Manual (10, 50 rind 100 yr. maps included in th Design and Procedure Manual). Adjust 6 hr. precipitation (if necessary) so that it is within the range of 45% to 65% of the 24 hr. precipitation. (Not applicable to Desert) of the precipitation on the rit side 4) Draw a line through the point parallel to the -t4 1 fl J1 5) This line is the intensity-duration curve for the location being analyzed 5. iz-rJ. fl[11.jr:j,:.;;4.0 . Application Form: LL R1)3 0) Selected Frequency 0 yr. P6 = _____ P24 24 2.0 . Adjusted *5 i!FIr 1.5 3) t = mm. 4) I = In/hr. 1TffflfftiiII Iiii 11 .0 *Not Applicable to Desert Region APPENDIX XI 10 15 20 30 40 50 1 2 3 4 5 6 IV-A-14 /QIZ 1r- -r1rr;TrilTrrnull £ I ir -iuiit -i-iiir . . . • i. i.i LI I i irr1ir. if. Equation: I 7.44 6 D'645 ' I, I Intensity (In./Hr.) ': L ' p6 6 Hr. Precipitation (In.) D = Duration (Min.) 4• 1 , h1J.i_4i. .,,,. ,.., rr1itr -17 'u _ll Ii a1.ii Drainage Study La Costa Greens - Recreation Center I CHAPTER 6 REFERENCES I 6.3 - Nomograph for Determination of Time of Concentration I (Tc) for Natural Watersheds I AHah H:\REPORTS\2352962ND SUBMFflAL\A02.doc W.O. 2352-11296 5/26/2004 3:20 PM I I; 1 I I I I I I I . I I I I I I I: I N EQQT/ON Tee! Tcs (//. -9L H 5000 7: Z al one,i/rahai 4,04,0 L Len9/h o/ wa/er,si',ed Al' 01 -e17ce in e/eva/i'n along e/,eci'/4ve sIoe line (See 4opendi 8)7 .300o L 4l,Zs /e,4 lr'oeis Mimi/es 20tW 4 3 /90 9tJo 800 2 /20 700 /00 see solo 80 4 lOLl - / 60 3,00 2 200 JO / /80 Os— 20 300> SO 11 ID 2000 /2 3D NOTE /600 /0 9 NFOR NATURAL WATERSHBDS /200 3 20 ADD TEN MINUTES TO /000 900 7 COMPUTED TIME OF CON- [CENTRATION J 800 700 6' 680 £ /0 500 -3, 300 5 200 H 7 NOMOGRAPH FOR DETERMINATION OF TIME OF CONCENTRATION (Tc) FOR NATURAL WATERSHEDS SAN DIEGO COUNTY DEPARTMENT OF SPECIAL DISTRICT SERVICES *••••' Drainage Study La Costa Greens - Recreation Center CHAPTER 6 REFERENCES 6.4 - Urban Areas Overland Time of Flow Curves AHah H:\REPORTS235296\2ND SUBMITFAL\02.doc W.O. 2352-1126 512612004 3:20 PM Drainage Study La Costa Greens - Recreation Center CHAPTER 6 REFERENCES 6.5 - Runoff Coefficients (Rational Method) AH:ah H:\REPORTS\.2352\96\2ND SUBMITTAL\.A02.doc W.O. 2352-11296 5/26/2004 3:20 PM Coefficient, C Soil Group A. Q .40 .45 .50 .55 .45 .50 .60 .70 .45 .50 .55 .65 .30 .35 .40 .45• .70 .75 .80 .85 .80 .85 .90 .95 I Ii I I 1 I I I I I, I I I I 1 I I I I RUNOFF COEFFICIENTS (RATIONAL METHOD) DEVELOPED AREAS (URBAN) Land Use Residential: Single Family L Multi-Units Mobile Homes Rural (lots greater than 1/2 acre) Commercial 12 80% Impervious Industrial 121 90% Impervious NOTES: Soil Group maps are available at the offices of the Department of Public Works. Where actual conditions deviate significantly from the tabulated imperviousness values of 80% or 90%, the values given for coefficient C, may be revised by multiplying 801/6 or 90% by the ratio of actual imperviousness to the tabulated imperviousness. However, in no case shall the final coefficient be less than 0.50. For example: Consider commercial property on D soil group. Actual imperviousness = 50% Tabulated imperviousness = 80% Revised C = 50x 0.85 = 0.53 80 IV-A-9 APPENDIX IX I Drainage Study La Costa Greens - Recreation Center I I I CHAPTER 6 REFERENCES 6.6 - Excerpt from the "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens Phase / Neighborhoods 108 -114" AI:ah H:\REPORTS\2352\96'.2ND SUBMITTAL'.A02dac W.O. 2352-11296 5/26/2004 3:20 PM PLANNING ENGINEERING SURVEYING IRVINE LOS ANGELES RIVERSIDE SAN DIEGO I I I I I I I I I I I DAVE HAMMAR LEX WILLIMAN ALISA VIALPANDO I 10179 Huennekens St. San Diego, CA 92121 (858) 558-4500 PH (858)558-1414 F www.HunsakerSD.com Info@HunsakerSD.com MASTER HYDROLOGY STUDY & REVISED HYDRAULIC STUDY for LA COSTA GREENS - PHASE I NEIGHBORHOODS 1.08 -1.14 City of Carlsbad, California W.O. 2352-66 August 4, 2003 Al-I h:\reports\2352\066/aol.dac W.O. 2352-66 8/4/2003 10:21 AM Prepared for: Real Estate Collateral Management Company do Morrow Development 1903 Wright Place Suite 180 Carlsbad, CA 92008 Riond L. Martin, R.C.E. Project Manager Hunsaker & Associates San Diego, Inc. I? S ~~l 0/1 OXAD L. 4j A ti LU NO .48670 Jm Exp. 6/30/04 / OFCP&/ La Costa Greens - Phase I (Neighborhoods 1.08-1.14) I Master Hydrology Study and Revised Hydraulic Study 1 I CHAPTER 3 RATIONAL METHOD HYDROLOGIC ANALYSIS I (100-YEAR AES MODEL OUTPUT) I 3.2 - Ultimate Condition Neighborhoods 1.09, 1.10 and 1.12-North AH h:\rep0rtS2352\068a01 .doc W.O. 2352-66 8/4/2003 10:24 AM FLOWLENGTH(FEET) = 11.25 MANNING'S N = 0.013 ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPEFLOW THRU SUBAREA(CFS) = 5.81 TRAVEL TIME(MIN.) = 0.01 TC(MIN.) = 17.63 I FLOW PROCESS FROM NODE 348.00 TO NODE 348.00 IS CODE = 11 ---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 1 WITH THE MAIN-STREAM MEMORY<<<<< ** MAIN STREAM CONFLUENCE DATA ** STREAM I RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 5.81 17.63 3.156 3.02 1 ** MEMORY BANK # 1 CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) I 1 214.68 21.74 2.757 131.43 ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) 1 193.35 17.63 3.156 2 219.76 21.74 2.757 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 219.76 Tc(MIN.) = 21.74 TOTAL AREA(ACRES) = 134.45 FLOW PROCESS FROM NODE 348.00 TO NODE 348.00 IS CODE = 12 ---------------------------------------------------------------------------- >>>>>CLEAR MEMORY BANK 4$ 1 <<z<< **************************************************************************** FLOW PROCESS FROM NODE 348.00 TO NODE 348.00 IS CODE = 10 ---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK 4$ 2 <<<< **************************************************************************** FLOW PROCESS FROM NODE 352.00 TO NODE 353.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< *USER SPECIFIED (SUBAREA): SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .4800 INITIAL SUBAREA FLOW-LENGTH = 930.00 UPSTREAM ELEVATION = 291.00 DOWNSTREAM ELEVATION = 192.80 ELEVATION DIFFERENCE = 98.20 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 15.514 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. *CAUTION: SUBAREA FLOWLENGTH EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.427 SUBAREA RUNOFF(CFS) = 13.64 TOTAL AREA(ACRES) = 8.29 TOTAL RUNOFF(CFS) = 13.64 *********************** * *************************** ************************* FLOW PROCESS FROM NODE 353.00 TO NODE 354.00 IS CODE 3 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA.z<<<< >>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000 DEPTH OF FLOW IN 18.0 INCH PIPE IS 5.8 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 27.6 UPSTREAM NODE ELEVATION = 190.00 DOWNSTREAM NODE ELEVATION = 185:33 FLOWLENGTH(FEET) = 12.80 MANNING'S N = 0.013 ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = PIPEFLOW THRU SUBAREA(CFS) = 13.64 TRAVEL TIME(MIN.) = 0.01 TC(MIN.) = 15.52 **** *********************************************** *************** ***** ***** FLOW PROCESS FROM NODE 354.00 TO NODE 354.00 IS CODE = 8 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.426 *USER SPECIFIED(SUBAREA) SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .9500 SUBAREA AREA (ACRES) 0.46 SUBAREA RUNOFF(CFS) = 1.50 TOTAL AREA(ACRES) = 8.75 TOTAL RUNOFF(CFS) 15.13 TC(MIN) = 15.52 *********************** **************************** ******************** ***** FLOW PROCESS FROM NODE 354.00 TO NODE 348.00 IS CODE = 3 I >>>>>COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<<<<< >>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) <<<<< DEPTH OF FLOW IN 18.0 INCH PIPE IS 10.8 INCHES I PIPEFLOW VELOCITY(FEET/SEC.) = 13.7 UPSTREAM NODE ELEVATION = 185.00 DOWNSTREAM NODE ELEVATION = 183.10 I FLOWLENGTH(FEET) = 37.25 MANNING'S N = 0.013 ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = PIPEFLOW THRU SUBAREA(CFS) = 15.13 TRAVEL TIME(MIN.) 0.05 TC(MIN.) = 15.57 I Drainage Study La Costa Greens - Recreation Center CHAPTER 6 REFERENCES 6.7 - Hydrology Exhibit 9.3 from the "Master Hydrology Study & Revised Hydraulic Study for La Costa Greens Phase I Neighborhoods 1.08 -1.14" AH:ah I-1:\REPORTS\2352\96\2ND SUBMITTALAO2.doc W.O. 2352-11296 5/26/2004 3:20 PM ep-19-2003 / / I I ( / ;J /ç —! iiiJ- ;/f I PROJECT / $ ; / BOUNDARY / - / - - - -ç I \ / / Jj . \ \' '\ // / \\\.ç /7 • ' \ / J'1 .:i i ;!\ 4\ j, \ / / /1 / tj - 3 1 \\\\ \\\ /'\ \\ / :1 : : ; 13 1 L2I \ / / / / I V - .3') ....: I .,., .,.../ . I 1i 0 I -- 3 - -: - - - - :- - I I \ I I 11 !\ 1 je 1 3 I. 1 II I \ L\' -<:- : h / : I /JJL/) \ )/\U Iii ., ' 2/ \._. I....31,............../....I43 3\ - - / i/, / J\\\ \, ! I 'd I\ OFFSTE RUNOFF B I I /1 - - y/ 384 \ \ - \\ - :_J___ - 18 IJW1 L \ )}\'\ ) i 11, ... •\ / .\\. ../ .. 41 \\.1 / / 135 34 /1 \ - 32 334 43 -,-- -- - - / 7 \/lc,I! ./.C/;//9/ ,1 II ' 3 . ::.,:........ / ,,/ / 7 (i/n . / I hI III .4/m 39 \..7 \\. .35/ .'354 vi/,.:.\\ 1 ..@ . 1.7 'J //........: ....31/ f,I?i ............r \/ ,/ ' ,. 3/ . . 1•v . j ;3 31 OFF,SITE RUNOFF C "/LJ /. ../i/ p _-- \ 7 ,../\3 / /i/ .. . 3, - I ' ;:;- - Q100 = 129 8 cfs 301 /1.3,' t;, ::'T 39 . . // 38 , 2 . , - .. ' •:.Y =20.8mm. ...., 3.4f/( \\) .,.. ..,4Q . • .' __ \ ...'/_ / ./'5/3 ../// - ........... ... // ,/35 / I : 51 i - 3 // 4 '/331 3b 1/ - / J / ! 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'-!-.. ./__33._____._./... . / ,/.... '3,'' .43.r/,,. /tl///.4/f "' .33/0 % il \/ // I 7 L E G E .i D -, 13 33/ / / 1 '7' ./,L ( - (.) \,' WATERSHED BOUNDARY PROJECT BOUNDARY I \ A I I I LUVVLINL WATERSHED NODE BROW DITCH NODE ET F N. 03 (0 33 $: 4._ PREPARED FOR: HYDROLOGY EXHIBIT 93 SHE $V % 'K" ! ' \7 'd'7. I " - \ ' ., , 33.....................43 , -- - c~3. /3 ,/ "" 1/ -: IID / , . , ,/ / .. ENGINEERING San Diego, Ca 92121 I I&A 5/26/2004 Ri\0328\&Hyd\328$H05-ULT HYBRO 109 110 112N,dwgE 2086]S VII Drainage Study La Costa Greens - Recreation Center I CHAPTER 7 HYDROLOGY EXHIBITS Exhibit 7.1 Developed Condition Hydrology Map AH:ah H:\REP0RTS\2352\96\2N0 SUBMITTAL\A02.dec W.O. 2352-11296 5/26/2004 3:20 PM WATERSHED BOUNDARY WATERSHED SL WATERSHED ID FLOWLINE 3-BOUNDARY NODE PROPOSED STORM DRAIN EXISTING STORM DRAIN EXISTING DRAINAGE DITCH C) I 50 0 50 100 150 1 SCALE 1'=SO' NEI( NOTE: FLOWLINE DENOTES PATH OF RUNOFF WITHIN THE WATERSHED SUBAREA. 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