Loading...
HomeMy WebLinkAboutPD 2021-0002; 3304 JAMES DRIVE; HYDROLOGY AND HYDRAULICS STUDY FOR SINGLE FAMILY RESIDENCE AT 3304 JAMES DRIVE; 2021-04-01PLSA #3509 May 2021 HYDROLOGY & HYDRAULICS STUDY FOR SINGLE FAMILY RESIDENCE AT 3304 JAMES DRIVE CARLSBAD, CA 92008 PD 2021-0002 / GR 2021-0002 / DWG 529-2A PREPARED FOR: CALIFORNIA WEST CONSTRUCTION, INC. 5927 PRIESTLY DRIVE, SUITE 110 CARLSBAD, CA 92008 DATE: MAY 2021 PREPARED BY: PASCO LARET SUITER & ASSOCIATES 27127 CALLE ARROYO, SUITE 1904 SAN JUAN CAPISTRANO, CA 92675 _______________________________________5/26/21__ W. JUSTIN SUITER, RCE 68964 DATE PLSA #3509 May 2021 TABLE OF CONTENTS SECTION Executive Summary 1.0 Introduction 1.1 Existing Conditions 1.2 Proposed Project 1.3 Hydrologic Unit Contribution 1.4 Summary of Results and Conditions 1.5 Conclusions 1.6 References 1.7 Methodology 2.0 Introduction 2.1 County of San Diego Criteria 2.2 Runoff coefficient determination 2.3 Hydrology & Hydraulic Model Output 3.0 Pre-Developed Hydrologic Model Output (100 Year Event) 3.1 Post-Developed Hydrologic Model Output (100 Year Event) 3.2 Post-Developed Mitigated 100-year Hydrograph 3.3 Attachments 4.0 Isopluvial Maps Runoff Coefficients Basin Maps PLSA #3509 May 2021 1.0 EXECUTIVE SUMMARY 1.1 Introduction This Hydrology Study for the single-family residence at 3304 James Drive has been prepared to analyze the hydrologic and hydraulic characteristics of the existing and proposed project site. This report intends to present both the methodology and the calculations used for determining the runoff from the project site in both the pre-developed (existing) conditions and the post- developed (proposed) conditions produced by the 100 year 6-hour storm. In addition, this report will propose the sizing of all necessary storm drain facilities and storm drain piping necessary for the storm drain system to safely convey the runoff from the 100-year rainfall event. 1.2 Existing Conditions The project site is located at 3304 James Drive, and is bound by residential homes to the north, south, east and west, and James Drive to the west. The property is geographically located at N 33º09’48” W 117º20’02”. The existing project site is vacant. The site generally slopes from the southeast to northwest, toward James Drive. The subject property has an existing total gross area of 10,173 sf or 0.23 acres. Storm water from the southeast side of the property drains northwest toward James Drive where it then surface flows north to an existing public storm drain system that ultimately drains to the Pacific Ocean. 1.3 Proposed Project The proposed development will include the construction of a new single-family residence, hardscape, landscape, driveway, and a storm drain system. Proposed developments will translate into a 6,522 sf increase in impervious area. The proposed storm drain system design includes new PVC stormdrain and area drains, swales and an underground detention system by R-Tank XD. Runoff from the site will drain to proposed area drains and stormdrain that outlets to the proposed 9.84’x57.08’x0.82’ R-Tank XD below ground in the driveway for detention. From there, storm water will outlet through a 5” orifice to mitigate peak flow to a 6” PVC pipe, to a 12”x12” inlet/cleanout that will have two sidewalk underdrains to James Drive. Storm water will continue to flow north as it does in the existing condition. We believe the proposed storm drain system will not adversely affect the downstream system. To address the storm water quality goals established for this project, proposed permanent Best Management Practices (BMPs) will be incorporated into the storm water runoff design. The proposed BMPs include multiple landscape planter areas, directing impervious and roof area runoff to proposed landscape areas, which are intended to mitigate peak flows as well as serve as settling areas. 1.4 Hydrologic Unit Contribution The project site is located in the Buena Vista Creek Hydrologic Area, and more specifically, the El Salto Sub-Area (904.21). According to the California 1998 and 2002 CWA 303d list published by the San Diego Regional Water Quality Control Board, there are impaired water bodies that are associated with this basin, PLSA #3509 May 2021 the Buena Vista Lagoon is impaired for Indicator Bacteria, Nutrients, Sedimentation/Siltation and Toxicity. 1.5 Preliminary Hydrology Calculations The existing 100-year peak discharge from the site is 0.52 cfs, and is associated with a time of concentration (Tc) of 5 minutes and a total area of 0.23 acres. The post-project un-mitigated 100-year peak discharge from the site is 1.05 cfs, and is associated with a time of concentration (Tc) of 5 minutes and a total area of 0.23 acres. The post-project mitigated 100-year peak discharge from the site is 0.46 cfs. See sections 3.1, 3.2 & 3.3. Pre-project Q100 (cfs) Un-Mitigated Post-Project Q100 (cfs) Mitigated Post-Project Q100 (cfs) 0.52 1.05 0.46 1.6 Conclusions The proposed development and proposed storm drain design will be capable of safely conveying the 100-year storm runoff flow and has included storm drain piping to ensure that the discharge from the project site is of the best possible quality and will not pose any significant impact or threats to the water quality of Buena Vista Lagoon or the Pacific Ocean. In addition, the proposed development and storm drain improvements will not significantly alter the existing drainage patterns. There is an increase in storm water runoff that will be detained and will not increase the potential for flooding nor create an increase in erosion. This project has been deemed a Standard Project and therefore is not subject to Hydromodification criteria. It is with these above reasons that it can be concluded that there will be no negative impact to the downstream storm drain facilities or an increased potential of flooding. Since a major goal of this project is to ensure that all storm water quality issues are addressed to the maximum extent practical, the peak discharge for the proposed site will be utilized to adequately size the storm drain piping system for this project. 1.7 References “San Diego County Hydrology Manual”, revised June 2003, County of San Diego, Department of Public Works, Flood Control Section. ”California Regional Water Quality Control Board Order No. 2009-009-DWQ” California Regional Water Control Board, San Diego Region (SDRWQCB). PLSA #3509 May 2021 2.0 METHODOLOGY 2.1 Introduction The hydrologic model used to perform the hydrologic analysis presented in this report utilizes the Ration Method (RM) equation, Q=CIA. The RM formula estimates the peak rate of runoff based on the variables of area, runoff coefficient, and rainfall intensity. The rainfall intensity (I) is equal to: I = 7.44 x P6 x D-0.645 Where: I = Intensity (in/hr) P6 = 6-hour precipitation (inches) D = duration (minutes – use Tc) Using the Time of Concentration (Tc), which is the time required for a given element of water that originates at the most remote point of the basin being analyzed to reach the point at which the runoff from the basin is being analyzed, the RM equation determines the storm water runoff rate (Q) for a given basin in terms of flow (typically in cubic feet per second (cfs) but sometimes as gallons per minute (gpm)). The RM equation is as follows: Q = CIA Where: Q= flow (in cfs) C = runoff coefficient, ratio of rainfall that produces storm water runoff (runoff vs. infiltration/evaporation/absorption/etc) I = average rainfall intensity for a duration equal to the Tc for the area, in inches per hour. A = drainage area contributing to the basin in acres. The RM equation assumes that the storm event being analyzed delivers precipitation to the entire basin uniformly, and therefore the peak discharge rate will occur when a raindrop that falls at the most remote portion of the basin arrives at the point of analysis. The RM also assumes that the fraction of rainfall that becomes runoff or the runoff coefficient C is not affected by the storm intensity, I, or the precipitation zone number. 2.2 County of San Diego Criteria As defined by the County Hydrology Manual dated June 2003, the rational method is the preferred equation for determining the hydrologic characteristics of basins up to approximately one square mile in size. The County of San Diego has developed its own tables, nomographs, and methodologies for analyzing storm water runoff for areas within the county. The County has also developed precipitation isopluvial contour maps that show even lines of rainfall anticipated from a given storm event (i.e. 100-year, 6-hour storm). One of the variables of the RM equation is the runoff coefficient, C. The runoff coefficient is dependent only upon land use and soil type and the County of San Diego has developed a table of Runoff Coefficients for Urban Areas to be applied to basin located within the County of San Diego. The table categorizes the land use, the associated development density (dwelling units per acre) and the percentage of impervious area. Each of the categories listed has an associated runoff coefficient, C, for each soil type class. PLSA #3509 May 2021 The County has also illustrated in detail the methodology for determining the time of concentration, in particular the initial time of concentration. The County has adopted the Federal Aviation Agency’s (FAA) overland time of flow equation. This equation essentially limits the flow path length for the initial time of concentration to lengths under 100 feet, and is dependent on land use and slope. 2.3 Runoff Coefficient Determination As stated in section 2.2, the runoff coefficient is dependent only upon land use and soil type and the County of San Diego has developed a table of Runoff Coefficients for Urban Areas to be applied to basin located within the County of San Diego. The table, included at the end of this section, categorizes the land use, the associated development density (dwelling units per acre) and the percentage of impervious area. Weighted runoff coefficients were calculated based on the existing and proposed impervious areas for each basin per the County Hydrology Manual section 3.1.2. See section 3.0 for calculations. PLSA #3509 May 2021 3.0 HYDROLOGY MODEL OUTPUT Rational Method Parameters Runoff Coefficient C= 0.9 x (% Impervious) + Cp (1-% Impervious)* Cp=0.35* for pervious type “D” soils 100 Year 6 Hour Storm Precipitation (P6)=2.6 in (see rainfall isopluvial*) I= Intensity in/hr, I=7.44xP6xD-0.645* Duration (D)= Time of Concentration, Tc Q=Peak Runoff, Q=C*I*A (cfs) *From San Diego County Hydrology Manual, June 2003 Revision 3.1 Pre-Developed Hydrologic Model Output (100 Year Event) Total Basin Area= 10,169 sf A=0.23 acres Existing Impervious Area= 0 sf CPRE = (1* 0.9) + (0.0*0.35) CPRE =0.35 Tc = 5 min I = 7.44(2.6)(5) -0.645 I = 6.53 in/hr Q100= 0.35 * 6.53 in/hr * 0.23 acres Q100=0.52 cfs 3.2 Post-Developed Hydrologic Model Output (100 Year Event) Total Basin Area= 10,169 sf A=0.23 acres Proposed Impervious Area= 6,522 sf CPOST = (0.64* 0.9) + (0.36*0.35) CPOST = 0.70 Tc = 5 min I = 7.44(2.6)(5) -0.645 I = 6.53 in/hr Q100= 0.70 * 6.53 in/hr * 0.23 acres Q100=1.05 cfs TOTAL ∆Q =TOTAL Qpost-TOTAL Qpre TOTAL ∆Q = 1.05 cfs – 0.52 cfs TOTAL ∆Q = +0.53 cfs Rational Method Hydrograph Calculations for 3304 James Drive, Carlsbad CA Pre-developed Condition - 100 Year Event Q100=0.52 cfs Tc=5 min C=0.35 #= 72 P100,6=2.6 in A=0.23 acres (7.44*P6*D^-.645) (I*D/60) (V1-V0)(V/T)(Q=ciA) (Re-ordered) D I VOL VOL I (INCR)Q VOL ORDINATE #(MIN)(IN/HR)(IN)(IN)(IN/HR)(CFS)(CF)(CFS) 0 0 0.00 0.00 0.57 6.85 0.52 156 1 5 6.85 0.57 0.16 1.91 0.15 46 0.01 2 10 4.38 0.73 0.11 1.36 0.11 33 0.01 3 15 3.37 0.84 0.09 1.09 0.09 26 0.01 4 20 2.80 0.93 0.08 0.92 0.07 22 0.01 5 25 2.43 1.01 0.07 0.81 0.07 20 0.01 6 30 2.16 1.08 0.06 0.73 0.06 18 0.01 7 35 1.95 1.14 0.06 0.66 0.05 16 0.01 8 40 1.79 1.19 0.05 0.61 0.05 15 0.01 9 45 1.66 1.25 0.05 0.57 0.05 14 0.01 10 50 1.55 1.29 0.04 0.53 0.04 13 0.01 11 55 1.46 1.34 0.04 0.50 0.04 12 0.01 12 60 1.38 1.38 0.04 0.48 0.04 12 0.01 13 65 1.31 1.42 0.04 0.45 0.04 11 0.02 14 70 1.25 1.46 0.04 0.43 0.03 10 0.02 15 75 1.19 1.49 0.03 0.42 0.03 10 0.02 16 80 1.15 1.53 0.03 0.40 0.03 10 0.02 17 85 1.10 1.56 0.03 0.38 0.03 9 0.02 18 90 1.06 1.59 0.03 0.37 0.03 9 0.02 19 95 1.03 1.62 0.03 0.36 0.03 9 0.02 20 100 0.99 1.65 0.03 0.35 0.03 8 0.02 21 105 0.96 1.68 0.03 0.34 0.03 8 0.02 22 110 0.93 1.71 0.03 0.33 0.03 8 0.02 23 115 0.91 1.74 0.03 0.32 0.03 8 0.02 24 120 0.88 1.76 0.03 0.31 0.02 7 0.02 25 125 0.86 1.79 0.03 0.30 0.02 7 0.02 26 130 0.84 1.81 0.02 0.29 0.02 7 0.02 27 135 0.82 1.84 0.02 0.29 0.02 7 0.02 28 140 0.80 1.86 0.02 0.28 0.02 7 0.02 29 145 0.78 1.89 0.02 0.27 0.02 7 0.02 30 150 0.76 1.91 0.02 0.27 0.02 6 0.02 31 155 0.75 1.93 0.02 0.26 0.02 6 0.02 32 160 0.73 1.95 0.02 0.26 0.02 6 0.02 33 165 0.72 1.98 0.02 0.25 0.02 6 0.03 34 170 0.70 2.00 0.02 0.25 0.02 6 0.03 35 175 0.69 2.02 0.02 0.24 0.02 6 0.03 36 180 0.68 2.04 0.02 0.24 0.02 6 0.03 37 185 0.67 2.06 0.02 0.23 0.02 6 0.03 38 190 0.66 2.08 0.02 0.23 0.02 6 0.03 39 195 0.64 2.10 0.02 0.23 0.02 5 0.03 40 200 0.63 2.11 0.02 0.22 0.02 5 0.04 41 205 0.62 2.13 0.02 0.22 0.02 5 0.04 Pre developed Hydrograph.xls 4/15/2021 Rational Method Hydrograph Calculations for 3304 James Drive, Carlsbad CA Pre-developed Condition - 100 Year Event 42 210 0.61 2.15 0.02 0.22 0.02 5 0.04 43 215 0.61 2.17 0.02 0.21 0.02 5 0.05 44 220 0.60 2.19 0.02 0.21 0.02 5 0.05 45 225 0.59 2.21 0.02 0.21 0.02 5 0.07 46 230 0.58 2.22 0.02 0.20 0.02 5 0.07 47 235 0.57 2.24 0.02 0.20 0.02 5 0.11 48 240 0.56 2.26 0.02 0.20 0.02 5 0.15 49 245 0.56 2.27 0.02 0.20 0.02 5 0.52 50 250 0.55 2.29 0.02 0.19 0.02 5 0.09 51 255 0.54 2.31 0.02 0.19 0.02 5 0.06 52 260 0.54 2.32 0.02 0.19 0.02 5 0.05 53 265 0.53 2.34 0.02 0.19 0.02 5 0.04 54 270 0.52 2.35 0.02 0.18 0.01 4 0.03 55 275 0.52 2.37 0.02 0.18 0.01 4 0.03 56 280 0.51 2.38 0.02 0.18 0.01 4 0.03 57 285 0.50 2.40 0.01 0.18 0.01 4 0.02 58 290 0.50 2.41 0.01 0.18 0.01 4 0.02 59 295 0.49 2.43 0.01 0.17 0.01 4 0.02 60 300 0.49 2.44 0.01 0.17 0.01 4 0.02 61 305 0.48 2.46 0.01 0.17 0.01 4 0.02 62 310 0.48 2.47 0.01 0.17 0.01 4 0.02 63 315 0.47 2.48 0.01 0.17 0.01 4 0.02 64 320 0.47 2.50 0.01 0.17 0.01 4 0.02 65 325 0.46 2.51 0.01 0.16 0.01 4 0.02 66 330 0.46 2.53 0.01 0.16 0.01 4 0.02 67 335 0.45 2.54 0.01 0.16 0.01 4 0.01 68 340 0.45 2.55 0.01 0.16 0.01 4 0.01 69 345 0.45 2.57 0.01 0.16 0.01 4 0.01 70 350 0.44 2.58 0.01 0.16 0.01 4 0.01 71 355 0.44 2.59 0.01 0.15 0.01 4 0.01 72 360 0.43 2.61 0.00 0.00 0.00 0 0.01 SUM=746 cubic feet 0.02 acre-feet Pre developed Hydrograph.xls 4/15/2021 Rational Method Hydrograph Calculations for 3304 James Drive, Carlsbad CA Pre-developed Condition - 100 Year Event 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0 50 100 150 200 250 300 350 400Q (cfs)Time (min) RM-HYDROGRAPH Project Pre developed Hydrograph.xls 4/15/2021 Rational Method Hydrograph Calculations for 3304 James Drive, Carlsbad CA Post-developed Condition - 100 Year Event Q100=1.05 cfs Tc=5 min C=0.7 #= 72 P100,6=2.6 in A=0.23 acres (7.44*P6*D^-.645) (I*D/60) (V1-V0)(V/T)(Q=ciA) (Re-ordered) D I VOL VOL I (INCR)Q VOL ORDINATE #(MIN)(IN/HR)(IN)(IN)(IN/HR)(CFS)(CF)(CFS) 0 0 0.00 0.00 0.57 6.85 1.05 315 1 5 6.85 0.57 0.16 1.91 0.31 92 0.02 2 10 4.38 0.73 0.11 1.36 0.22 66 0.03 3 15 3.37 0.84 0.09 1.09 0.18 53 0.03 4 20 2.80 0.93 0.08 0.92 0.15 45 0.03 5 25 2.43 1.01 0.07 0.81 0.13 39 0.03 6 30 2.16 1.08 0.06 0.73 0.12 35 0.03 7 35 1.95 1.14 0.06 0.66 0.11 32 0.03 8 40 1.79 1.19 0.05 0.61 0.10 30 0.03 9 45 1.66 1.25 0.05 0.57 0.09 28 0.03 10 50 1.55 1.29 0.04 0.53 0.09 26 0.03 11 55 1.46 1.34 0.04 0.50 0.08 24 0.03 12 60 1.38 1.38 0.04 0.48 0.08 23 0.03 13 65 1.31 1.42 0.04 0.45 0.07 22 0.03 14 70 1.25 1.46 0.04 0.43 0.07 21 0.03 15 75 1.19 1.49 0.03 0.42 0.07 20 0.03 16 80 1.15 1.53 0.03 0.40 0.06 19 0.03 17 85 1.10 1.56 0.03 0.38 0.06 19 0.03 18 90 1.06 1.59 0.03 0.37 0.06 18 0.03 19 95 1.03 1.62 0.03 0.36 0.06 17 0.03 20 100 0.99 1.65 0.03 0.35 0.06 17 0.03 21 105 0.96 1.68 0.03 0.34 0.05 16 0.04 22 110 0.93 1.71 0.03 0.33 0.05 16 0.04 23 115 0.91 1.74 0.03 0.32 0.05 15 0.04 24 120 0.88 1.76 0.03 0.31 0.05 15 0.04 25 125 0.86 1.79 0.03 0.30 0.05 15 0.04 26 130 0.84 1.81 0.02 0.29 0.05 14 0.04 27 135 0.82 1.84 0.02 0.29 0.05 14 0.04 28 140 0.80 1.86 0.02 0.28 0.05 14 0.04 29 145 0.78 1.89 0.02 0.27 0.04 13 0.04 30 150 0.76 1.91 0.02 0.27 0.04 13 0.05 31 155 0.75 1.93 0.02 0.26 0.04 13 0.05 32 160 0.73 1.95 0.02 0.26 0.04 12 0.05 33 165 0.72 1.98 0.02 0.25 0.04 12 0.05 34 170 0.70 2.00 0.02 0.25 0.04 12 0.05 35 175 0.69 2.02 0.02 0.24 0.04 12 0.06 36 180 0.68 2.04 0.02 0.24 0.04 12 0.06 37 185 0.67 2.06 0.02 0.23 0.04 11 0.06 38 190 0.66 2.08 0.02 0.23 0.04 11 0.06 39 195 0.64 2.10 0.02 0.23 0.04 11 0.07 40 200 0.63 2.11 0.02 0.22 0.04 11 0.07 41 205 0.62 2.13 0.02 0.22 0.04 11 0.08 Post developed Hydrograph.xls 4/15/2021 Rational Method Hydrograph Calculations for 3304 James Drive, Carlsbad CA Post-developed Condition - 100 Year Event 42 210 0.61 2.15 0.02 0.22 0.03 10 0.09 43 215 0.61 2.17 0.02 0.21 0.03 10 0.10 44 220 0.60 2.19 0.02 0.21 0.03 10 0.11 45 225 0.59 2.21 0.02 0.21 0.03 10 0.13 46 230 0.58 2.22 0.02 0.20 0.03 10 0.15 47 235 0.57 2.24 0.02 0.20 0.03 10 0.22 48 240 0.56 2.26 0.02 0.20 0.03 10 0.31 49 245 0.56 2.27 0.02 0.20 0.03 9 1.05 50 250 0.55 2.29 0.02 0.19 0.03 9 0.18 51 255 0.54 2.31 0.02 0.19 0.03 9 0.12 52 260 0.54 2.32 0.02 0.19 0.03 9 0.09 53 265 0.53 2.34 0.02 0.19 0.03 9 0.08 54 270 0.52 2.35 0.02 0.18 0.03 9 0.07 55 275 0.52 2.37 0.02 0.18 0.03 9 0.06 56 280 0.51 2.38 0.02 0.18 0.03 9 0.05 57 285 0.50 2.40 0.01 0.18 0.03 9 0.05 58 290 0.50 2.41 0.01 0.18 0.03 9 0.05 59 295 0.49 2.43 0.01 0.17 0.03 8 0.04 60 300 0.49 2.44 0.01 0.17 0.03 8 0.04 61 305 0.48 2.46 0.01 0.17 0.03 8 0.04 62 310 0.48 2.47 0.01 0.17 0.03 8 0.04 63 315 0.47 2.48 0.01 0.17 0.03 8 0.03 64 320 0.47 2.50 0.01 0.17 0.03 8 0.03 65 325 0.46 2.51 0.01 0.16 0.03 8 0.03 66 330 0.46 2.53 0.01 0.16 0.03 8 0.03 67 335 0.45 2.54 0.01 0.16 0.03 8 0.03 68 340 0.45 2.55 0.01 0.16 0.03 8 0.03 69 345 0.45 2.57 0.01 0.16 0.03 8 0.03 70 350 0.44 2.58 0.01 0.16 0.03 8 0.03 71 355 0.44 2.59 0.01 0.15 0.02 7 0.03 72 360 0.43 2.61 0.00 0.00 0.00 0 0.03 SUM=1494 cubic feet 0.03 acre-feet Post developed Hydrograph.xls 4/15/2021 Rational Method Hydrograph Calculations for 3304 James Drive, Carlsbad CA Post-developed Condition - 100 Year Event 0.00 0.20 0.40 0.60 0.80 1.00 1.20 0 50 100 150 200 250 300 350 400Q (cfs)Time (min) RM-HYDROGRAPH Project Post developed Hydrograph.xls 4/15/2021 PLSA #3509 May 2021 3.3 Post-Developed Mitigated 100-year Hydrograph 2L Inflow to R-tank 3P Tank Routing Diagram for 3509 Prepared by Pasco Laret Suiter & Associates, Printed 4/8/2021 HydroCAD® 10.10-5a s/n 10097 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link ---[> 0 D 6 [j .------___J 3509 Printed 4/8/2021Prepared by Pasco Laret Suiter & Associates Page 2HydroCAD® 10.10-5a s/n 10097 © 2020 HydroCAD Software Solutions LLC Summary for Link 2L: Inflow to R-tank Inflow =1.05 cfs @ 4.08 hrs, Volume=0.026 af Primary =1.05 cfs @ 4.08 hrs, Volume=0.026 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs DISCHARGE Imported from RatHydro adj.csv Link 2L: Inflow to R-tank Inflow Primary Hydrograph Time (hours) 95908580757065605550454035302520151050Flow (cfs)1 0 DISCHARGE Imported from RatHydro adj.csv 1.05 cfs 1.05 cfs D 3509 Printed 4/8/2021Prepared by Pasco Laret Suiter & Associates Page 3HydroCAD® 10.10-5a s/n 10097 © 2020 HydroCAD Software Solutions LLC Summary for Pond 3P: Tank Inflow =1.05 cfs @ 4.08 hrs, Volume=0.026 af Outflow =0.46 cfs @ 4.14 hrs, Volume=0.026 af, Atten= 57%, Lag= 3.6 min Primary =0.46 cfs @ 4.14 hrs, Volume=0.026 af Routing by Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 155.65' @ 4.14 hrs Surf.Area= 562 sf Storage= 354 cf Plug-Flow detention time= 21.6 min calculated for 0.026 af (100% of inflow) Center-of-Mass det. time= 21.9 min ( 252.2 - 230.3 ) Volume Invert Avail.Storage Storage Description #1 154.95'415 cf Custom Stage Data (Conic) Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(%)(cubic-feet)(cubic-feet)(sq-ft) 154.95 562 0.0 0 0 562 155.77 562 90.0 415 415 631 Device Routing Invert Outlet Devices #1 Primary 154.95'5.0" Round Culvert L= 10.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 154.95' / 154.85' S= 0.0100 '/' Cc= 0.900 n= 0.013, Flow Area= 0.14 sf Primary OutFlow Max=0.46 cfs @ 4.14 hrs HW=155.65' (Free Discharge) 1=Culvert (Barrel Controls 0.46 cfs @ 3.34 fps)t_ 3509 Printed 4/8/2021Prepared by Pasco Laret Suiter & Associates Page 4HydroCAD® 10.10-5a s/n 10097 © 2020 HydroCAD Software Solutions LLC Pond 3P: Tank Inflow Primary Hydrograph Time (hours) 95908580757065605550454035302520151050Flow (cfs)1 0 Peak Elev=155.65' Storage=354 cf 5.0" Round Culvert n=0.013 L=10.0' S=0.0100 '/' 1.05 cfs 0.46 cfs D PLSA #3509 May 2021 4.0 ATTACHMENTS Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2020 Page 1 of 436694373669445366945336694613669469366947736694853669437366944536694533669461366946936694773669485468845468853468861468869468877468885468893468901468909468917468925 468845 468853 468861 468869 468877 468885 468893 468901 468909 468917 468925 33° 9' 49'' N 117° 20' 2'' W33° 9' 49'' N117° 19' 59'' W33° 9' 47'' N 117° 20' 2'' W33° 9' 47'' N 117° 19' 59'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 15 30 60 90Feet 0 5 10 20 30Meters Map Scale: 1:375 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. USDA = MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: San Diego County Area, California Survey Area Data: Version 15, May 27, 2020 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jan 24, 2020—Feb 12, 2020 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2020 Page 2 of 4USDA = □ D D D D D D D D ,,..,,,. ,,..,,,. □ ■ ■ □ □ ,,..._., t-+-t ~ tllWI ,..,,. ~ • Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI CgC Chesterton-Urban land complex, 2 to 9 percent slopes D 0.2 80.9% MlC Marina loamy coarse sand, 2 to 9 percent slopes B 0.1 19.1% Totals for Area of Interest 0.3 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2020 Page 3 of 4USDA = Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2020 Page 4 of 4~ San Diego County Hydrology Manual Date: June 2003 • Section: Page: Table 3-1 RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use Runoff Coefficient "C" Soil Type NRCS Elements County Elements %IMPER. A B Undisturbed Natural Terrain (Natural) Permanent Open Space 0* 0.20 0.25 Low Density Residential (LDR) Residential, 1.0 DU/ A or less 10 0.27 0.32 Low Density Residential (LDR) Residential, 2.0 DU/A or less 20 0.34 0.38 Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41 Medium Density Residential (MOR) Residential, 4.3 DU/A or less 30 0.41 0.45 Medium Density Residential (MOR) Residential, 7.3 DU/A or less 40 0.48 0.51 Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54 Medium Density Residential (MOR) Residential, 14.5 DU/ A or less 50 0.55 0.58 High Density Residential (HDR) Residential, 24.0 DU/ A or less 65 0.66 0.67 High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77 Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 Commercial/Industrial (Limited I.) Limited Industrial 90 0.83 0.84 Commercial/Industrial (General I.) General Industrial 95 0.87 0.87 C 0.30 0.36 0.42 0.45 0.48 0.54 0.57 0.60 0.69 0.78 0.78 0.81 0.84 0.84 0.87 3 6 of26 D 0.35 0.41 0.46 0.49 0.52 0.57 0.60 0.63 0.71 0.79 0.79 0.82 0.85 0.85 0.87 *The values associated with 0% impervious may be used for direct calculation of the runoff coefficient as described in Section 3.1.2 (representing the pervious runoff coefficient, Cp, for the soil type), or for areas that will remain undisturbed in perpetuity. Justification must be given that the area will remain natural forever ( e.g., the area is located in Cleveland National Forest). DU/ A = dwelling units per acre NRCS = National Resources Conservation Service 3-6 57'-1" (29 XD R-TANKS)9'-10" (6 XD R-TANKS)MAINTENANCE PORT (TYP OF 2, LOCATIONS TO BE VERIFIED BY ENGINEER)2'-0" STONE PERIMETER R-TANKXD 5 STACK (TYP. OF 174)R-TANKXD SYSTEM LAYOUTLOW PROFILE TANKCARLSBAD, CASITE DESIGNATION: UGDSACF ENVIRONMENTAL, 1-800-448-3636, www.acfenvironmental.com FOR ADDITIONAL INFORMATION PLEASE CONTACT: ACF ENVIRONMENTAL 1-800-448-3636 www.acfenvironmental.com DRAWN BY SHEET NO. DATE 04/13/21 DVB 1 of 5 LAYOUT SCALE 1" = 5' R-TANKXD PANEL STACK HEIGHT 5 PANELS HIGH TRAFFIC LOAD HS-20 # OF 5 STACK R-TANKXD MODULES 174 TOTAL SYSTEM STORAGE 677 CF R-TANK STORAGE VOLUME 415 CF STONE STORAGE VOLUME 262 CF TANK INVERT 158.67 INVERT OF STONE BASE (3")158.42 TOP OF R-TANK ELEV.159.49 TOP OF COVER STONE ELEV. (2") 159.66 MIN. STONE PERIMETER WIDTH 2.0 FT SEE SHEETS 3 - 5 FOR DETAILS AND ADDITIONAL INFORMATION 00 5'10' SCALE 1" = 5' ENGINEER OF RECORD TO REVIEW, APPROVE AND ENDORSE FINAL SITE SPECIFIC DESIGN. PAVED SURFACE 3" STONE BASE 2" R-TANKXD TANK WRAP & EXCAVATION ENVELOPE DETAIL R-TANKᴴᴰ UNITS WRAPPED WITH 8 OZ. NON-WOVEN GEOTEXTILE (OR EQUAL) EXCAVATION WRAPPED WITH 8 OZ. NON-WOVEN GEOTEXTILE (OR EQUAL) 158.42 158.67 159.49 159.66 Products Distributed by: California Filtration Specialists Contact us for infonnation and pricing: info@cafiltrationspecialists.com 11021 Via Frontera, Suite E San Diego, CA 92127 (858) 705-6483 Fax: (858) 487-8355 i L_ -- I \ l cFs \ CALIFORNIA FILTRATION SPECIALISTS '-_/ -- ---- - ~ \ I\ \ ------ -------- ---- ---- • \ ------ ---- ---- ---- ---- -- VZZZZZZTOZZZZZZZZZZZZTOZZZZZZZZZZZTOZTR7ZZZZZZZTOZTOZTOZTRZZZZTOZTOZTazzzzzzazz----- 7 I I I I I I _J Al f' LET'S GET IT DONE FOR ADDITIONAL INFORMATION PLEASE CONTACT: ACF ENVIRONMENTAL 1-800-448-3636 www.acfenvironmental.com R-TANKXD SYSTEM DETAILSLOW PROFILE TANKCARLSBAD, CASITE DESIGNATION: UGDSACF ENVIRONMENTAL, 1-800-448-3636, www.acfenvironmental.comDRAWN BY SHEET NO. DATE 04/13/21 DVB 2 of 5 ENGINEER OF RECORD TO REVIEW, APPROVE AND ENDORSE FINAL SITE SPECIFIC DESIGN. R-TANKXD QUANTITIES R-TANKXD PANEL STACK HEIGHT 5 PANELS HIGH # OF 5 STACK R-TANKXD MODULES 174 TOTAL SYSTEM STORAGE 677 CF R-TANK STORAGE VOLUME 415 CF STONE STORAGE VOLUME (40% VOID RATIO)262 CF STONE BED FOOTPRINT 846 SF STONE QUANTITY 32 CY 8 OZ. NON-WOVEN GEOTEXTILE TANK WRAP 1,418 SF (158 SY) 8 OZ. NON-WOVEN GEOTEXTILE EXCAVATION WRAP 2,215 SF (246 SY) 12" MAINTENANCE PORTS 2 NOTE: STONE QUANTITY INCLUDES 12" OF COVER AND 3" OF BASE. NOTE: GEOTEXTILE / LINER QUANTITIES INCLUDE A 15% WASTE FACTOR. R-TANKXD - MODULE DETAIL GEOMETRY: LENGTH = 23.62 IN. (600 MM) WIDTH = 19.68 IN. (500 MM) HEIGHT = 9.84 IN. (250 MM) TANK VOLUME = 2.65 CF STORAGE VOLUME = 2.38 CF VOID INTERNAL VOLUME: 90% VOID SURFACE AREA: 90% MODULE DATA TANK INV=158.67 TOP OF TANK=159.49 R-TANKXD - ELEVATION STONE BASE INV=158.423"LOAD RATING: 240.2 PSI, (MODULE ONLY) HS20-25, (WITH ACF COVER SYSTEM) MATERIAL: 100% RECYCLED POLYPROPYLENE 23.62"9.84"19.68"1.97"23.62"19.68"ENDCOVERMIN. 6"MAX. 16.67'9.84"ISOMETRIC SIDE PAVED SURFACE MAX. FINAL GRADE=176.16 MIN. FINAL GRADE=159.99 TOP R-TANKXD TYPICAL TANK INLET/OUTLET W/ GEOTEXTILE PIPE BOOT DETAIL PIPE O.D. PIPE ± 5.0'PIPE O.D. 2'-0" STAINLESS STEEL BAND ± 5.0' GEOTEXTILE FABRIC OVER ACF R-TANK INLET/OUTLET PIPE "X" CUT IN THE FABRIC TO ALLOW PIPE/TANK INTERFACE END VIEW OF PIPE/FABRIC CONNECTION NOTE: PIPE MUST BUTT DIRECTLY AGAINST R-TANK. PIPE EFFLUENT SHALL NOT PASS THROUGH FABRIC ENVELOPE STAINLESS STEEL BAND USED TO FASTEN FABRIC TO PIPES TO PREVENT BACKFILL FROM ENTERING STRUCTURE FRONT VIEW OF GEOTEXTILE BOOT SIDE VIEW OF GEOTEXTILE BOOTGEOTEXTILE BOOT SIDE VIEW OF PIPE/FABRIC CONNECTION CUT AN “X” IN THE FABRIC ENVELOPE THAT IS SLIGHTLY LARGER THAN THE PIPE. PULL THE FABRIC FLAPS AROUND THE PIPE, AND SEAL WITH A STAINLESS STEEL BAND. GEOTEXTILE FABRIC OVER ACF R-TANK AFTER TANK WRAP IS SECURED TO PIPE, SLIDE BOOT AGAINST R-TANK AND SECURE WITH SECOND STAINLESS STEEL BAND, THEN ATTACH BOOT FLAP TO TANK ENVELOPE FABRIC WITH DUCT TAPE OR OTHER ADHESIVE. FABRIC COLLAR TO FIT OUTSIDE DIAMETER OF INLET/OUTLET PIPE 12 OZ/SY NON-WOVEN GEOTEXTILE, TRIM AS NEEDED STAINLESS STEEL BAND GEOTEXTILE FABRIC OVER ACF R-TANK T 1 I' :::::::= 'S' '''" " '" i-,~ '" "' ,\~~-,, = ,V I I I ( +158.6 +158.3 +1sa.1 +158.4 +158.8 +1sa.4 +1sa.e +1sa.s +158.8 +1sa.s +158.9 +1sa.a +1:its.6 (/) t' (/) t· (/) ~ 58.8 (/) i I ! (/) +158.9 I (/) t,,.. I (/) ~ +1sa.s SCALE: 1" = 1---1 -~ i 20 10 0 20 ~ n "' !, i,l ~ ls -..., 40 r , __ '-, VEGE~ -/ +\,. EXISTING RESIDENTIAL L. _____ _ +1s9.1 +1ss.2 +159.3 +159.2 GRVL +159.3 159 +1ss.1 +159.3 CONG -v-v-v-v-v-~ +159.5 +159.3 +159.5 { J\--- VEGETATION +159.3 +1s9.7 +159.3 +159.1 r-1'~ • A...A... ~ .,,.._,.._,.,__ ~ LOW VEGETATION +159.3 ....,__ +159,3 { ~_,A.._,A._,A.._,A._,l\._,A.._,A_A.._A_J +159.7 ·~ V-Vv-vvvv-v:;\ +159.< +159.3 159.t +159.4 VEGETATION +159.3 +159.4 +159.5 ~)--v-,_ PAYERS r +159.3 >,. ,/✓ -{ +159.4 +1s9.4 ~A..., f +1ss.2 +159.4 CONG +159.71 +1ss.s I I j ..._+_,, •. , __ (-=aA- fLNTRBOX I ,> fLNTRBOX l +159.4 +159.7 +1ss.a +159.8 CONG +159.4 +159.7 +1ss.s +1ss.2 +1ss.sl I _J" ~/ EXISTING RESIDENTIAL +1ss.s +159.7 " " " 60 --r-rv +159.7 EXISTING HYDROLOGY MAP 3304 JAMES DRIVE +159.7 +159.6 1\ +159.9 +159.9 +159.7 +159.6 +159.6 +159.7 +159.9 +159.8 >< VEGETATION +159.8 /~:'L I '\J / >< 1-I ✓r :_11 1 i - + VEGETATION ) X VEGETATION / 159.a o..ir-I +160.3 160.'4- -----, -4;11 ---,_/ +159.8 OE x -- +159.7 +159.8 +159.9 +159.8 +159.8 LOW VEGETATION / I \✓ +160.2 '--, \ \ ~ I I I I I ( J +160.0 "1 +160.1 +160.1 +160.3 +1ao.2 ~ '-\ I· r- < +160.3 I tE ! m ,! □ ~ g z ~ ~ +160.4 r +160.7 ~ ~ ~ +100.0 +160.0 / +160.0 'f81NARE~ 1-9, ~ZF (0.23 AC) +160.3 +160.5 i n ~ +160.7 " ~ I I) I +160.1 +160.1 \ +1ao.1 +160.4 +160.4 +160.3 IMPERVIOUS AREA ~ 0 +160.7 r G) i r f ~ I - +160.7 f LSCP GRVL 0 SF ,~ ~ iii /! I r,;,,-.- +158.3 ~iii i f l +158.4 ~ J "11 ~ ~, +1sa.4 l r-;:::;: ' I +1 58.5 ( iii +158.8 156.9 f,l ii =! l/ l " +158 .5 0 z ~ \ ~ ~ 0 11 +158.9 159.0 ,1~ n +w• '-=r--, I - ~ V w ______. " ( ::; '!&/ iii !/ \ I I SCALE: 1" = 20' -1 -~ i 20 10 0 20 w EXISTING RESIDENTIAL L. --.1.~,.-----.......:::....--->.--r--:---------'~-----:-:=-=--:::--~-----7i_ .84'X57.08'X0.82 ., GRVL +159.3 w +15•/i f i w +1sa.j l ' I ~Jfl ~ I ,~ [/l 0 i w ;,; ~I w I 40 1-.:....:...:-4,---__:_;,__:_;, __ ......._, __ """'-,;;'-=$=.----;-;::;:-:----r--xo R-TANK___ ---CO-NC-------t +159.4 +159.2 CONG +159.2 60 +159.71 +1se.s I +1se.sl +159.5 PROPOSED HYDROLOGY MAP 3304 JAMES DRIVE ( CONG ~ \ +159.4 ~ +159.6 +159.7 - VEGETATION APN: 205-060-46\- 3296 JAMES DR J ORELLA3296 LLC ! ); +159.8 >< I~: I I / >< ~ I \_17 \ i- ) X VEGETATION / / +100.3 160.-4-x -- r- r==,19==: I :==:::~t::::\== I rn: □:~ ~ I ~ +160.7 I ~ ~ I P N: 05-060-41 301 LLEY ST I MAH DE IREE H;NSrY ~ I ~ =! 0 I I r :rl I - IMPERVIOUS AREA .___ ____ _. 6,522 SF