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HomeMy WebLinkAboutPD 2018-0052; REED RESIDENCE; DRAINAGE STUDY; 2020-10-20I CIVIL + STRUCTURAL DRAINAGE STUDY PREPARED FOR: REED RESIDENCE APN: 156-231-21-00 1375 Buena Vista Way Carlsbad, CA 92008 October 20, 2020 PREPARED BY: LAMAR Engineering, Inc. Civil + Structural 217 Landis Avenue Chula Vista, CA 91910 DEC 172020 N% www.lamareng.com 217 Landis Avenue, Chula Vista, CA. 91910. LAND DEVELOPMENT ENGNEERING TABLE OF CONTENTS Page No. Introduction 3 Proposed Improvements 3 Hydrology Analysis and Methodology of Existing Conditions 3 Hydrology Analysis and Methodology of Proposed Conditions 3 Hydrologic Results 4 Conclusions 5 References 5 Vicinity & Location Map 6 EXHIBITS "1": Exhibit Watershed Basins 8 APPENDICES Appendix "A": Hydrologic Calculations - Rational Method 9 Developed Condition 100-Year Appendix "B": Hydrologic Calculations - Rational Method 9 Developed Condition 100-Year Appendix "C": Detention Basin Calculations 9 Appendix "D": References 12 2 INTRODUCTION General This report presents a drainage study for the property located at along Buena Vista Way, east of San Diego Freeway, west of the Elmwood St. with an APN: 156-231-21-00 (Project) in the City of Carlsbad, California. The purpose of this report is to estimate storm runoff discharges and appropriately design the proposed drainage improvements associated with the referenced property. The 100-year event will be considered for both the existing and proposed conditions. Proposed Improvements The proposed improvements include grading to accommodate a two-story single-family residence with attached two-car garage, a detached garage/workshop & an ADU both at the rear of the property, and hardscape improvements. The project site currently consists of a lot with an existing front asphalt concrete driveway, a one-story dwelling unit, a 2- car garage and an ADU which will be demolished to accommodate the proposed private improvements. The proposed drainage system will mimic the existing drainage pattern and basins designated to determine the runoff amounts and to properly size any drainage systems, if required. Drainage improvements are proposed to convey runoff associated with the project. The proposed drainage improvements will include a bioretention channel at the front of the property to collect the runoff from the property and allow detention and infiltration into the existing ground and any overflow to be convey by a 3" underdrain pipe into an existing concrete basin. Hydrology Analysis and Methodology of Existing Conditions The Rational Method was used to calculate the 100-year peak storm flows for the existing subbasin. A weighted Runoff Coefficient (C) of 0.71 was determine for each existing subbasin for the percentage of develop type (Table 1). A time of concentration (Tc) was determine for each subbasin. The existing project site drainage area is approximately 0.39 acres. The site drainage area will be discharged northerly towards Buena Vista Way. Hydrology Analysis and Methodology of Proposed Conditions As with the existing drainage conditions, the Rational Method was used to calculate the peak flows from the proposed subbasins. Again, in Appendix D, the guidelines and parameter used for the Rational Method can be found. A weighted Runoff Coefficient (C) was determine for each existing subbasin for the percentage of develop type (Table 2). A time of concentration (Tc) was determine for each subbasin. 3 Subbasin B-i (0.05 ac) drainage area consist of a detached garage/workshop, an ADU and landscape drainage. This area sheet will flow southerly and captured into landscape. Subbasin B-2 (0.28 ac) drainage area consist of new concrete driveway, a proposed two- story residence with attached garage, new hardscape and landscape. Partial flow will convey into a proposed 3'x 3' vegetated swale and deposited on a 2'x2' catch basin .The remaining basin area sheet will convey from hardscape into two different proposed 2'x2' catch basins. The three proposed catch basins will finally convey into a 8'x15' biofiltration basin. Subbasin B-3 (0.06 ac) drainage area consist of a concrete driveway, hardscape and landscape areas. This basin area sheet flows partially northly into landscape, the remaining basin will discharge directly into Buena Vista Way. The runoff captured by the biofiltration basin will be conveyed into an existing concrete basin by a 3" underdrain pipe. HYDROLOGIC RESULTS The Rational Method Hydrologic calculations for the 100-year, 6-Hour Storm Events, existing and proposed, are shown in Appendix "A" and "B", respectively. The following 40 table presents a summary of the design storm runoff calculations: Table 1: Existing Drainage Conditions- QCIA Sub- Basin Runoff Coeficient (C) Area (Acres) Tc (mm.) 100 yr Storm Intensity (I) Q1 00 (cfs) A-1 0.66 0.170 5.00 6.6 0.74 A-2 0.71 0.220 5.58 6.1 0.96 TOTAL 0.390 1.70 Table 2: Proposed Drainage Conditions - QCIA Sub- Basin Runoff Coeficient (C) Area (Acres) Tc (mm.) 100 yr Storm Intensity (I) Q1 00 (cfs) B-1 0.54 0.050 6.35 5.6 0.15 B-2 0.77 0.280 4.69 6.6 1.42 B-3 0.50 0.060 8.57 4.7 0.14 TOTAL 0.390 1.71 Summary (100-Year): Existing Conditions 40 Total Area = 0.39 AC Total Flow = 1.70 cfs Proposed Conditions Total Area = 0.39 AC Total Flow = 1.71 cfs *Difference in runoff Q0.01 cfs (increase) CONCLUSIONS Analysis of the existing and proposed conditions have been performed, and the finding establish as shown on the hydrologic analysis results. As noted on the summary hydrologic table, the difference between the post and pre- development flows will be capture on a bioretention basin located in the front side of the property. Partial flow will convey to Buena Vista Way by sheet flow through the driveway and the rest of the flow will be conveyed to Buena Vista Way from an existing concrete Basin by an underdrain pipe. Therefore, no impact to the downstream conditions exists. In addition, no increase in erosion or siltation will occur as the project is implemented LID in the form of landscape area and dispersion of runoff into the proposed detention basin. The proposed two-story single-family residence is outside a SFHA (Special Flood Hazard Area) zone (Zone X); The proposed grading improvements pad elevation of 132.75 for the main garage, 133.50 for the main residence, 132.50 for the detached garage/workshop and 132.50 for the ADU, will be rise in elevation and therefore will not be impacted by the 100-year flood zone. Similarly, this proposed does not proposed any significant risk of loss, injury or death involving flooding. REFERENCES County of San Diego, San Diego County Hydrology Manual (2003) Accurate Land Survey, Topographic Survey (December 2007) S J Of VICIN p LEUCADIA PROJECT SrrE C3 0 a \\ \\cn NORTH S me 0 EXHIBIT 661" WATERSHED BASINS PFOECT DESCRF770fir I. DENWEN EAISITNG MAIN DNEWN6 GARAGE AND AD(I 2 PROPOSED NEW DPV.J.JNG NEW C RADE/01P7CE NEW G4R40*)ItWK9l NEW ADU. ZCWING P-f LE(24L M7159 PAR I APII 756.231.21.00 lS7RUC77cAV TWE V-B OCCUPANCY a.456 PS/Ti SPRINKLERS YES FPAPOD BUILDING HETDIIT 24!_0 MAIN ONEWNG 986DI GARAGE 114405F ADU 552w TOTAL Z978DI S7RUC7ZIR4L LOT COVERAGE, LOT I 7,336DI x 40% ALLOWABLE 6.9S4DI PRLW COWRADEE, OALL SQUARE FOOTA 2-STORY DHELJJNG &064DI 4.010DI (IF 1,8439-+(F 216731r) ATTAaIED GAP40E 509DI GARAc,1$CKS°ILW 8609' 6605F I-STORY A.D.L/. 6405F 640$ TOTAL 19.4% 4364DI 5819DI FRrAVP 20' S'DE. 9202'+ 9101'Y-5 — 92015' x .10 — 9.2015' REARI 92075' x .20 — 16.403' SFIE DESIGN., * NEW IAWOUS CLWLWETE DRVWWAY AREA 45625F * NEW IMPERWWS COYDEE7E YARD AREA 409OW NEW IMPERWOUS BUILDING AREA .564DI * TOTAL 6.15% 1 f,006 - VICINITY MAP em 6)198 96)18 LEGEND SUB-BASIN BOUNDARY xx SUB-BASIN DESIGNATION XX SUB-BASIN AREA (ACRES) ciO, NODE —.—p...—..—FLOW PATH BASIN AREA C I QIOO Tc A-1 0.17 0.66 6.6 0.74 5.0 A-2 0.22 0.71 6.1 0.96 5.5 EXISTiNG DRAINAGE SUMMARY: THE DIS17NG STE is CtWRE7i7LY UI DEVELOPED CLWOITTQYS • SURFACE RUN(7F I4HL COY WY AND DISCHARGE OdREC1LY INTO A CONCRETE BADIN LOCA lED IN BUENA WSTA WAY. THE RUNOFF BILL FLOW DOHWSI1TEAM INTO A S7771M EWAIN OWANNEI. LOCA TEL IN PlO PICO OW AND FINALLY LYIAR(V 70 BUENA WSTA CREEX CCSYA NOTE: THE PRO,EOT IS NOT LOCATED IN LW HILL NOT REX1W LW DIL4IN FRGI ANY CRI77CAL CWRSE SECROVT WELD AREA. SOILS NOTE: THE PROECT DITE IS aviipar LOCATED MVTHUI A TWE B a.ASEIFTED AREA PER NR GROUNDWATER NOTE: DEPTH 70 WATER TA MORE THAN 80 INCHES 0 NORTH GRAPHIC SCALE (IN PEN?) lih — loft ff CITY OF CARLSBAD SHEETL ENGINEERING DEPARThIENT PEE DEVELOPMENT REED RESIDENCE DRAINAGE PLAN 7016 1375 BUENA VISTA WAY CARLSBAD, CA 92008 APN: 156-231-21-00 11115 SHEET APPROVETh JASON S. GELDERT JTY GlOWER RCE 63912 EERRES 9/30/16 DATE BY: PROJECT NO. DRAWING NO. D BY: _........... SD BY: 616148 IP -U 0 0 $ NORTH GRAPHIC SCALE ( IN FT) 114- loft. Uri LENGTH AS— \J f NE(SS.4RY ' .,1°jL____,t Q- pujG WA 'T rAa IJ 7 OUTLErprr jE 1 INVERT PER PLAN 5 A1ED .._ TWO NO N MISS -- DR D.0 AWO 120 AMIE APART 70 V'STALLED WiN HOLES PEA(XD ATBOTTENL BIORETENTION BASIN HiS SHEET CITY OF CARLSBAD ISH ENGINEERING DEPARTMENT POST DEVELOPMENT REED RESIDENCE DRAINAGE PLAIT ) 1375 BUENA VISTA WAY CARLSBAD, CA 92008 APN: 156-231-21-00 TiTLE SHEET APPROVED: JASON S. GEEDERT CITY ENGINEER RCE 63912 EXPIRES 9/30/18 DATE OWN BY: PROJECT NO. DRAVLNG NO. HKD BY: RW1D BY: VICINITY MAP U K JI TOTAL LOT AREA =17.159 SQ/FT (0.39 Ac) TOTAL DISTURBED AREA 19,I67 SQ/FT (0.44 Ac) (THIS AREA IND.UDES BUT IS NOT UMITED TO CPF-9TE WORK INCLIJOING PUBLIC IMPRO%€MENIS AND IEMPORARY DISTURBANCE SUCH AS VEHICLE AND EQUIPMENT STAGING ARE.45 CORSIRUCIION WORKER FOOT TRAFFIC. SC4L/GIRAAEI. PILES. UIIUTY TRENCHES. BACKFILL CUTS AND SLOPE KEYWAYS) TOTAL REPLACED IMPERWOUS AREA -0.252 AC TOTAL PROPOSED IMPERATOUS A.I1EA 0.260 AC PROPOSED DRAINAGE SUMMARY THE PROPOSED TE NELL DRAIN THE RUNOFF T0WAF)S THE ØDRTLIRATTDR WiN PARTTAL REMV77ON OAN AT THE NORTH EAST CaWYER OR THE 57E WA (.WDERDRAIN PIPES THE PROPOSED 94911 NELL PRO WOE 80TH WAlER QUALITY TREATMENT A?IV FLOW CWTRCY. TREATMENT THE DISCHARGE NELL ENTER THE UNOUND SIDRM S)1E11 ThWOUDR THE DRAINAGE' BASH LOCATED IN BUENA VISTA WAY AND CDRWY 10 BUENA WSTA CREEK TO FINALLY D(SOFIARGE INTO THE PACIFIC OMW SEE NKgIT FOR BUP MENG CALaATTDRS CCSYA NOTE: THE PROJECT (S NOT LOCATED 81 DR NELL NOT RECEIVE DR DRAIN FROM ANY DRII7C4L COURW 91VdMENT VIEW AREA. SOILS NOTE: THE PR0ECT 57F IS ENTIRELY L0C41W NEIWIN A TYPE B CLASVRED AREA PER NRCS GROUNDWATER NOTE: DEPTH TO WATER TABLE* MORE THAN 80 INGES LEGEND - SUB-BASIN BOUNDARY 9 xx SUB-BASIN DESIGNATION XX SUB-BASIN AREA (ACRES) NODE —..._.....—FLOW PATH BASIN AREA C I QIOD Tc B-1 0.05 0.54 5.6 0.15 6.3 B-2 0.28 0.77 6.6 1.42 4.6 B-3 0.06 0.50 4.7 0.14 8.5 I APPENDIX "A" HYDROLOGY CALCULATIONS RATIONAL METHOD PRE-DEVELOPED CONDITION (EXISTING) 100-YEAR 11 100-year (Existing) Rational Method Flowrate Calculations Project: I REED RESIDENCE I Subarea: I A-I I Date:! 10/20/20! STREAM #1 F- NODES ____ NODES 1 132 TO r 1301 [(FLOW ACROSS THE INITIAL SUBAREAS] Area Subarea (A): Enter: Al =1 0.170 acres Soil Type = (Appendix A SDCHM) Impervous All =1 0.102 I acres Impervous Ai % = Pervous Al =1 0.07 I acres Coefficient of Runoff (C): Enter: C = 0.66 I (Table 3-1 of San Diego County Hydrology Manual) Slope (5): Enter: s = 12.0 1(enter percentage, not decimal value) Watercourse Distance (D): Enter: D =[ 100 ifeet Enter D(adjusted) = 1 100 feet Initial Overland Flow (t1): Ti = 1.8*(1 .1_C)*Dtl2 Ti I 3.5 Iminutes 6-hr Storm Precipitation (P6): Enter: P6=r 2.5 ]inches P6(adjusted)=1 2.50 inches Intensity of Rainfall (I): = 744*p*T 0.645 1 =1 6.6 u in/hr (Table 3-2 of the Hydrology Manual) Ti minimum= 5 minutes 24-hr Storm Precipitation (P24): (Hydrology Manual - 100 Year Rainfall-24 Hours) Enter: P24= inches P6/P24= 53.1915 % 0.95392 Discharge (Q) at Node I 130 Q= C'lA1 Q=I 0.74 Icfs 0 100-year (Existing) Rational Method Flowrate Calculations Project: REED RESIDENCE I Subarea:l A-2 I Date:I 10/20/201 STREAM #1 _____ NODES 132 1 TO 1 131 1 L!cLAPROSS THE INITIAL SUBAREA)] Area Subarea (A): Enter: A2 =[ 0.220 1 acres Soil Type = F C 1 (Appendix A SDCHM) ImpervousA2=1 0.15 1 acres lmpervousA2%=I PervousA2=I 0.07 I acres Coefficient of Runoff (C): Enter: C =1 0.71 I (Table 3-1 of San Diego County Hydrology Manual) Slope (s): Enter: s =F 2.0 1(enter percentage, not decimal value) Watercourse Distance (D): Enter: D =: 88 Ifeet Enter D(adjusted) = 100 feet Initial Overland Flow (t1): Ti 1.8*(1.1C)*Dtl2 . S1!3 Ti=I 5.6 Iminutes 6-hr Storm Precipitation (P6): Enter: P6= 2.5 Jinches 6 (adjusted)=I 2.50 inches Intensity of Rainfall (I): I = 744*p*T 0.645 1 =1 6.1 uin/hr (Table 3-2 of the Hydrology Manual) Ti minimum= 5 minutes 24-hr Storm Precipitation (P24): (Hydrology Manual - 100 Year Rainfall-24 Hours) Enter: P24=r4.7_jinches P6/P24= 53.1915 % 0.95392 Discharge (Q) at Node I 131 Q = CIA, Q1 0.96 Icfs 0 APPENDIX "B" HYDROLOGY CALCULATIONS RATIONAL METHOD POST-DEVELOPED CONDITION (PROPOSED) 100-YEAR 100-year (Proposed) Rational Method Flowrate Calculations Project: I REED RESIDENCE Subarea: I B-I I Date: I 10/20/20 I STREAM #1 ______ ______ NODES r132 I TO [ 131 1 [(FLOW ACROSS THE INITIAL SUBARJ Area Subarea (A): Enter: Bi =1 0.05 1 acres Soil Type = r C (Appendix A SDCHM) Impervous Bi = I 02 acres Impervous Bi % =1 40% PervousBi =1 0.03 I acres Coefficient of Runoff (C): Enter: C =1 0.54 I (Table 3-1 of San Diego Country Hydrology Manual) Slope (s): Enter: s =[ 4.0---7 (enter percentage, not decimal value) Watercourse Distance (D): Enter: D = 25 Ifeet Enter D(adjusted) = 100 feet Initial Overland Flow (ti): Ti = 1 .8*(1.1_C)*Du2 . T1 1 6.4 Iminutes 6-hr Storm Precipitation (P6): Enter: P6=[2.5linches 6 (adjusted)=1_2.50 inches Intensity of Rainfall (I): I = 744*p*T0.645 1 =1 5.6 un/hr (Table 3-2 of the Hydrology Manual) Ti minimum= 5 minutes 24-hr Storm Precipitation (P24): (Hydrology Manual - 100 Year Rainfall-24 Hours) Enter: P24 [ 4.7inches P6/P24= 53.1915 % 0.95392 Discharge (Q) at Node I 131 Q C*I*A1 Q1_0.15 Icfs C 100-year (Proposed) Rational Method Flowrate Calculations Project: I REED RESIDENCE J Subarea: I B-2 I Date: I 10/20/20 I STREAM #1 ____ _______ NODES 133 TO 31 1 [JLOWACROSS THE INITIAL SUBAREA)] Area Subarea (A): Enter: B2=1 028 1 acres Soil Type =[ C1 (Appendix A SDCHM) lmpervousB2=r 022 1 acres ImpervousB2%=I PervousB2=I 0.060 acres Coefficient of Runoff (C): Enter: C =1 0.77 I (Table 3-1 of San Diego Country Hydrology Manual) Slope (s): Enter: s = 2.0 1(enter percentage, not decimal value) Watercourse Distance (D): Enter: D =T 95 lfeet Enter D(adjusted) 100 ifeet Initial Overland Flow (t1): 1.8*(1.1C)*Dtt2 . S113 Ti =J 4.7 Iminutes 6-hr Storm Precipitation (P6): Enter: p6=[ 2.5 linches '6 (adjusted)=1 2.50 jinches Intensity of Rainfall (I): I = 744*p*T 0.645 1 =1 6.6 uin/hr (Table 3-2 of the Hydrology Manual) Ti minimum= 5 minutes 24-hr Storm Precipitation (P24): (Hydrology Manual - 100 Year Rainfall-24 Hours) Enter: P24=[__477_7 inches P6/P24= 53.1915 % 0.95392 Discharge (Q) at Node I 131 Q= C'IA1 Q1 1.42 Icfs 100-year (Proposed) Rational Method Flowrate Calculations Project: I REED RESIDENCE I Subarea: I B-3 I Date: ( 10/20/20 I STREAM #1 __ ______ NODES [ 133 TO [ 132.51 r(FLOW ACROSS THE INITIAL SUBAREAFj Area Subarea (A): Enter: B3=[ 0.06 acres Soil Type =r C1 (Appendix A SDCHM) lmpervousB3=[ 0702---7 acres Impervous B3 % =1 Pervous B3 =I 0.04 I acres Coefficient of Runoff (C): Enter: C =1 0.50 I (Table 3-1 of San Diego Country Hydrology Manual) Slope (s): Enter: s =E 2.0 j(enter percentage, not decimal value) Watercourse Distance (D): Enter: D =fl 33 ]feet Enter D(adjusted) = 100 Ifeet Initial Overland Flow (ti): = 1.8*(1.1C)*Dtt2 . T=I 8.6 Iminutes 6-hr Storm Precipitation (P6): Enter: P6=[ 2.5 inches 6 (adjusted)= 1 2.50 Inches Intensity of Rainfall (I): I = 744*p*T 0.645 1 =1 4.7 un/hr (Table 3-2 of the Hydrology Manual) Ti minimum= 5 minutes 24-hr Storm Precipitation (P24): (Hydrology Manual - 100 Year Rainfall-24 Hours) Enter: P24 [T inches P6/P24= 53.1915 % 0.95392 Discharge (0) at Node I 132.5 I Q = CIA, QI 0.14 Icfs 0 APPENDIX "C" DETENTION BASIN CALCULATION S 10 S SDHM 3.1 PROJECT REPORT Project Name: Biofiltration Basin Reed Site Name: Reed Residence Site Address: 1375 Buena Vista Way City : Carlsbad, CA 92008 Report Date: 10/26/2020 Gage : BONITA Data Start : 10/01/1971 Data End : 09/30/2004 Precip Scale: 1.00 Version Date: 2020/04/07 Low Flow Threshold for POC 1 : 50 Percent of the 2 Year High Flow Threshold for POC 1: 10 year PREDEVELOPED LAND USE Name : Basin A Bypass: No 5 GroundWater: No Pervious Land Use acre C,NatVeg,Moderate .14 Pervious Total 0.14 Impervious Land Use acre IMPERVIOUS-FLAT 0.25 Impervious Total 0.25 Basin Total 0.39 Element Flows To: Surface Interflow MITIGATED LAND USE Name : Bypass: No GroundWater: No Groundwater . Pervious Land Use acre C,NatVeg,Moderate .13 Pervious Total 0.13 Impervious Land Use acre IMPERVIOUS-FLAT 0.26 Impervious Total 0.26 Basin Total 0.39 Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention Name : Bioretention 1 Bottom Length: 15.00 ft. Bottom Width: 8.00 ft. Material thickness of first layer: 1.5 Material type for first layer: Mulch Material thickness of second layer: 1.5 . Material type for second layer: ESM Material thickness of third layer: Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet): 0.5 Orifice Diameter (in.): 0.4 Offset (in.): 0.15 Flow Through Underdrain (ac-ft.): 2.733 Total Outflow (ac-ft.): 4.891 Percent Through Underdrain: 55.88 Discharge Structure Riser Height: 0.5 ft. Riser Diameter: 12 in. Element Flows To: Outlet 1 Outlet 2 Bioretention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infi1t(cfs) 0.0000 0.0028 0.0000 0.0000 0.0000 0.0549 0.0028 0.0000 0.0000 0.0000 0.1099 0.0028 0.0001 0.0000 0.0000 0.1648 0.0028 0.0001 0.0000 0.0000 0.2198 0.0028 0.0002 0.0000 0.0000 0.2747 0.0028 0.0002 0.0000 0.0000 0.3297 0.0028 0.0003 0.0000 0.0000 . 0.3846 0.0028 0.0003 0.0000 0.0000 0.4396 0.0028 0.0004 0.0000 0.0000 0.4945 0.0028 0.0004 0.0000 0.0000 0.5495 0.0028 0.0005 0.0000 0.0000 0.6044 0.0028 0.0005 0.0002 0.0000 0.6593 0.0028 0.0005 0.0003 0.0000 0.7143 0.0028 0.0006 0.0004 0.0000 0.7692 0.0028 0.0006 0.0004 0.0000 0.8242 0.0028 0.0007 0.0005 0.0000 0.8791 0.0028 0.0007 0.0006 0.0000 0.9341 0.0028 0.0008 0.0007 0.0000 0.9890 0.0028 0.0008 0.0007 0.0000 1.0440 0.0028 0.0009 0.0007 0.0000 1.0989 0.0028 0.0009 0.0010 0.0000 1.1538 0.0028 0.0010 0.0010 0.0000 1.2088 0.0028 0.0010 0.0010 0.0000 1.2637 0.0028 0.0010 0.0010 0.0000 1.3187 0.0028 0.0011 0.0011 0.0000 1.3736 0.0028 0.0011 0.0012 0.0000 1.4286 0.0028 0.0012 0.0013 0.0000 1.4835 0.0028 0.0012 0.0014 0.0000 1.5385 0.0028 0.0013 0.0015 0.0000 1.5934 0.0028 0.0013 0.0016 0.0000 1.6484 0.0028 0.0014 0.0017 0.0000 1.7033 0.0028 0.0014 0.0017 0.0000 1.7582 0.0028 0.0015 0.0018 0.0000 1.8132 0.0028 0.0015 0.0019 0.0000 . 1.8681 0.0028 0.0015 0.0020 0.0000 1.9231 0.0028 0.0016 0.0020 0.0000 1.9780 0.0028 0.0016 0.0021 0.0000 2.0330 0.0028 0.0017 0.0021 0.0000 2.0879 0.0028 0.0017 0.0022 0.0000 2.1429 0.0028 0.0018 0.0023 0.0000 2.1978 0.0028 0.0018 0.0023 0.0000 2.2527 0.0028 0.0019 0.0024 0.0000 2.3077 0.0028 0.0019 0.0024 0.0000 2.3626 0.0028 0.0020 0.0025 0.0000 2.4176 0.0028 0.0020 0.0026 0.0000 2.4725 0.0028 0.0020 0.0026 0.0000 2.5275 0.0028 0.0021 0.0027 0.0000 2.5824 0.0028 0.0021 0.0027 0.0000 2.6374 0.0028 0.0022 0.0028 0.0000 2.6923 0.0028 0.0022 0.0028 0.0000 2.7473 0.0028 0.0023 0.0028 0.0000 2.8022 0.0028 0.0023 0.0029 0.0000 2.8571 0.0028 0.0024 0.0029 0.0000 2.9121 0.0028 0.0024 0.0030 0.0000 2.9670 0.0028 0.0025 0.0030 0.0000 3.0220 0.0028 0.0025 0.0031 0.0000 3.0769 0.0028 0.0026 0.0031 0.0000 3.1319 0.0028 0.0026 0.0031 0.0000 3.1868 0.0028 0.0027 0.0032 0.0000 3.2418 0.0028 0.0028 0.0032 0.0000 3.2967 0.0028 0.0028 0.0033 0.0000 . 3.3516 3.4066 0.0028 0.0028 0.0029 0.0030 0.0033 0.0034 0.0000 0.0000 3.4615 0.0028 0.0030 0.0034 0.0000 S 3.5165 0.0028 0.0031 0.0034 0.0000 3.5714 0.0028 0.0031 0.0035 0.0000 3.6264 0.0028 0.0032 0.0035 0.0000 3.6813 0.0028 0.0033 0.0035 0.0000 3.7363 0.0028 0.0033 0.0036 0.0000 3.7912 0.0028 0.0034 0.0037 0.0000 3.8462 0.0028 0.0035 0.0038 0.0000 3.9011 0.0028 0.0035 0.0039 0.0000 3.9560 0.0028 0.0036 0.0040 0.0000 4.0000 0.0028 0.0036 0.0087 0.0000 Surface retention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To mended(cfs) Wetted Surface 4.0000 0.0028 0.0036 0.0000 0.0087 0.0000 4.0549 0.0028 0.0038 0.0000 0.0087 0.0000 4.1099 0.0028 0.0039 0.0000 0.0087 0.0000 4.1648 0.0028 0.0041 0.0000 0.0087 0.0000 4.2198 0.0028 0.0042 0.0000 0.0087 0.0000 4.2747 0.0028 0.0044 0.0000 0.0087 0.0000 4.3297 0.0028 0.0045 0.0000 0.0087 0.0000 4.3846 0.0028 0.0047 0.0000 0.0087 0.0000 4.4396 0.0028 0.0048 0.0000 0.0087 0.0000 4.4945 0.0028 0.0050 0.0000 0.0087 0.0000 4.5495 0.0028 0.0051 0.1165 0.0087 0.0000 4.6044 0.0028 0.0053 0.3555 0.0087 0.0000 4.6593 0.0028 0.0054 0.6597 0.0087 0.0000 4.7143 0.0028 0.0056 0.9966 0.0087 0.0000 4.7692 0.0028 0.0058 1.3333 0.0087 0.0000 S 4.8242 0.0028 0.0059 1.6378 0.0087 0.0000 4.8791 0.0028 0.0061 1.8845 0.0087 0.0000 4.9341 0.0028 0.0062 2.0620 0.0087 0.0000 4.9890 0.0028 0.0064 2.1826 0.0087 0.0000 5.0000 0.0028 0.0064 2.3230 0.0087 0.0000 Name : Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Bioretention 1 ANALYSIS RESULTS Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.14 Total Impervious Area:0.25 Mitigated Landuse Totals for POC #1 5 Total Pervious Area:0.13 Total Impervious Area:0.26 Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow (cfs) 2 year 0.120361 5 year 0.165578 10 year 0.176619 25 year 0.248669 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow (cfs) 2 year 0.104035 5 year 0.151714 10 year 0.165352 25 year 0.234884 POC #1 The Facility PASSED The Facility PASSED. Flow(cfs) Predev Mit Percentage Pass/Fail 0.0602 143 98 68 Pass 0.0614 131 92 70 Pass . 0.0625 123 88 71 Pass 0.0637 116 82 70 Pass 0.0649 110 78 70 Pass 0.0661 102 73 71 Pass 0.0672 96 69 71 Pass 0.0684 90 67 74 Pass 0.0696 85 65 76 Pass 0.0708 84 63 75 Pass 0.0719 82 61 74 Pass 0.0731 73 59 80 Pass 0.0743 69 58 84 Pass 0.0755 66 56 84 Pass 0.0766 64 53 82 Pass 0.0778 59 52 88 Pass 0.0790 58 50 86 Pass 0.0802 57 46 80 Pass 0.0814 57 44 77 Pass 0.0825 54 42 77 Pass 0.0837 52 40 76 Pass 0.0849 49 38 77 Pass 0.0861 45 37 82 Pass 0.0872 45 34 75 Pass 0.0884 42 33 78 Pass 0.0896 40 32 80 Pass 0.0908 39 31 79 Pass 0.0919 39 30 76 Pass 0.0931 39 30 76 Pass is 0.0943 0.0955 38 38 30 30 78 78 Pass Pass 0.0966 37 26 70 Pass 0.0978 34 24 70 Pass 0.0990 32 23 71 Pass 0.1002 30 22 73 Pass 0.1013 27 20 74 Pass 0.1025 27 19 70 Pass 0.1037 26 19 73 Pass 0.1049 25 16 64 Pass 0.1061 24 16 66 Pass 0.1072 24 16 66 Pass 0.1084 23 16 69 Pass 0.1096 23 16 69 Pass 0.1108 22 14 63 Pass 0.1119 22 14 63 Pass 0.1131 21 13 61 Pass 0.1143 21 13 61 Pass 0.1155 21 13 61 Pass 0.1166 21 13 61 Pass 0.1178 19 13 68 Pass 0.1190 17 13 76 Pass 0.1202 17 13 76 Pass 0.1213 14 12 85 Pass 0.1225 13 11 84 Pass 0.1237 11 10 90 Pass 0.1249 10 10 100 Pass 0.1260 10 10 100 Pass 0.1272 10 10 100 Pass 0.1284 10 9 90 Pass . 0.1296 10 9 90 Pass 0.1307 10 9 90 Pass 0.1319 9 9 100 Pass 0.1331 9 9 100 Pass 0.1343 9 9 100 Pass 0.1355 9 9 100 Pass 0.1366 9 9 100 Pass 0.1378 9 9 100 Pass 0.1390 9 9 100 Pass 0.1402 9 9 100 Pass 0.1413 9 9 100 Pass 0.1425 9 9 100 Pass 0.1437 9 9 100 Pass 0.1449 9 9 100 Pass 0.1460 9 9 100 Pass 0.1472 9 9 100 Pass 0.1484 9 8 88 Pass 0.1496 8 7 87 Pass 0.1507 8 7 87 Pass 0.1519 8 6 75 Pass 0.1531 7 6 85 Pass 0.1543 7 5 71 Pass 0.1554 7 5 71 Pass 0.1566 7 4 57 Pass 0.1578 7 4 57 Pass 0.1590 7 4 57 Pass 0.1602 7 4 57 Pass 0.1613 0.1625 7 7 4 3 57 42 Pass Pass 0.1637 7 3 42 Pass . 0.1649 7 3 42 Pass 0.1660 6 3 50 Pass 0.1672 6 3 50 Pass 0.1684 6 2 33 Pass 0.1696 5 2 40 Pass 0.1707 5 2 40 Pass 0.1719 4 1 25 Pass 0.1731 4 1 25 Pass 0.1743 3 1 33 Pass 0.1754 3 1 33 Pass 0.1766 3 1 33 Pass Drawdown Time Results Perind and Impind Changes No changes have been made. This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, . and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by Clear Creek Solutions, Inc. 2005-2020; All Rights Reserved. 0 APPENDIX "D" REFERENCES 11 S 117°2 50 0/ 33'10'21"N Nationa. Flood Hazard Layer FiRMette . FEMA Feet - - 1.6,000 ii' 20'U?'VJ 0 250 500 1,000 1,500 2.000 Legend SEE FlU REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT Without Base Flood Elevation (BEE) Zo,,,' A. V 499 SPECIAL FLOOD With BFE or Depth Zsve 45 40 AH VS AR HAZARD AREAS Regulatory Floodway 0.2% Annual Chance Flood Hazard. Area of 1% annual chance flood with average depth less than one foot or with drainag areas of less than one square mile z Future Conditions 1% Annual Chance Flood Hazard - Area with Reduced Flood Risk due to OTHER AREAS OF Levee. See Notes. FLOOD HAZARD Area with Flood Risk due to Levee NO SCREEN Area of Minimal Flood Hazard I I Effective LOMRs OTHER AREAS Area of Undetermined Flood Hazard GENERAL - - - - Channel. Culvert, or Storm Sewer STRUCTURES iuiiuii Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5. Water Surface Elevation Coastal Transect -t'----. Base Flood Elevation Line (BFE) Limit of Study Jurisdiction Boundary Coastal Transect Baseline OTHER - - Profile Baseline FEATURES Hydrographic Feature Digital Data Available N No Digital Data Available MAP PANELS Unmapped The pin displayed on the map is an appronimatc point selected by the user and does not represe an authoritative property location. This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 10/1/2020 at 6:54 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. San Diego County Hydrology Manual Section: Date: June 2003 Page: 3 6 of 26 Table 3-1 RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use I Runoff Coefficient "C" - Soil Type NRCS Elements County Elements I % IMPER. A B C D Undisturbed Natural Terrain (Natural) Permanent Open Space 0.20 0.25 0.30 0.35 Low Density Residential (LOR) Residential, 1.O DU/A or less 10 0.27 0.32 0.36 0.41 Low Density Residential (L.DR) Residential, 2.0 DU/A or less 20 0.34 0.38 0.42 0.46 Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41 0.45 0.49 Medium Density Residential (MDR) Residential, 4.3 DU/A or less 30 0.41 0.45 0.48 0.52 Medium Density Residential (MDR) Residential, 7.3 DU/A or less 40 0.48 0.51 0.54 0.57 Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54 0.57 0.60 Medium Density Residential (MDR) Residential, 14.5 DU/A or less 50 0.55 0.58 0.60 0.63 High Density Residential (HDR) Residential, 24.0 DU/A or less 65 0.66 0.67 0.69 0.71 High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 0.78 0.79 Commercial/Industrial (N. Corn) Neighborhood Commercial 80 0.76 0.77 0.78 0.79 Commercial/Industrial (G. Corn) General Commercial 85 0.80 0.80 0.81 0.82 Commercial/Industrial (O.P. Corn) Office Professional/Commercial 90 0.83 0.84 0.84 0.85 Commercial/Industrial (Limited 1.) Limited Industrial 90 0.83 0.84 0.84 0.85 0.87 - Commercial/Industrial (General I.) General Industrial 95 0.87 0.87 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 . . . 100 30 U) I- Ui w I- Ui U. 0 Z 20 ILl L) Z - w z 0 -J Ui U. 10 az o LU Ui > 0 EXAMPLE: Given: Watercourse Distance (0) = 70 Feet Slope (s)=1.3% T= 1.8 (1.1-C) V Runoff Coefficient (C) = 0.41 3\/••• Overland Flow Time (T) = 9.5 Minutes SOURCE: Airport Drainage, Federal Aviation Administration, 1965 FIGURE Rational Formula - Overland Time of Flow Nomograph San Diego County Hydrology Manual Date: June 2003 Section: 3 Page 12of26 Note that the Initial Time of Concentration should be reflective of the general land-use at the upstream end of a drainage basin. A single lot with an area of two or less acres does not have a significant effect where the drainage basin area is 20 to 600 acres. Table 3-2 provides limits of the length (Maximum Length (LM) of sheet flow to be used in hydrology studies. Initial T1 values based on average C values for the Land Use Element are also included. These values can be used in planning and design applications as described below. Exceptions may be approved by the "Regulating Agency" when submitted with a detailed study. Table 3-2 MAXIMUM OVERLAND FLOW LENGTH (L 1) & INITIAL TIME OF CONCENTRATION (T Element* DU/ Acre .5% 1% 2% 3% 5% 10% LM Ti LM T1 LM Ti LM T1 LM Tj LM T1 Natural 50 13.2 70 12.5 85 10.9 100 10.3 100. 8.7 100 6.9 LDR 1 50 12.2 70 11.5 85 10.0 100 9.5 100 8.0 100 6.4 LDR 2 50 11.3 70 10.5 85 9.2 100 8.8 100 7.4 100 5.8 LDR 2.9 50 10.7 70 10.0 85 8.8 95 8.1 100 7.0 100 5.6 MDR 4.3 50 10.2 70 9.6 80 8.1 95 7.8 100 6.7 100 5.3 MDR 7.3 50 9.2 65 8.4 80 7.4 95 7.0 100 6.0 100 4.8 MDR 10.9 50 8.7 65 7.9 80 6.9 90 6.4 100 5.7 100 4.5 MDR 14.5 50 8.2 65 7.4 80 6.5 90 6.0 100 5.4 100 4.3 HDR 24 50 6.7 65 6.1 75 5.1 90 4.9 95 4.3 100 3.5 HDR 43 50 1 5.3 65 4.7 75 4.0 85 3.8 95 3.4 100 2.7 N.Com 50 5.3 60 4.5 75 4.0 85 3.8 95 3.4 100 2.7 G. Corn 50 4.7 60 4.1 75 3.6 85 3.4 90 2.9 100 2.4 O.P./Corn 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2 Limited I. 50 1 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2 General 1. 50 3.7 60 3.2 70 2.7 80 1 2.6 90 2.3 1 100 1.9 *See Table 3-1 for more detailed description 3-12 EQUATION LE - I11.9L3\0.385 Feet —5000 Ic - tiE) 5000 Ic = Time of concentration (hours) L a Watercourse Distance (miles) ...4000 /E = Change in elevation along I— effective slope line (See Figure 3-5) (feet) 30U0 Tc I— Hoursj Minutes 2000 _L 240 180 —1000 900 800 2 120 sa 100 90 _500\\ 80 —400 \ 70 1 60 — 300 50 —200 40 L Miles Feet 30 —100 1", 4000 20 18 3000 16 05 50 14 40 2000 12 1800 1600 10 30 1400 \ 9 1200 8 20 1000 7 900 800 6 700 5 600 10 500 4 400 3 300 -5 200 LE L Tc SOURCE: California Division of Highways (1941) and Kirpich (1940) Nomograph for Determination of Time of Concentration (Tc) or Travel Time (It) for Natural Vtersheds FIGURE 3..4 S - III '-==--L,- - — — — — — I :1 VA•UU ___ - - __ ___ r VAhl =WAM - - r 1 UIPJi . 1. __4A•I A____ - WA • m ____ - vas riii ____ - - FmmWJ ____ ___ FAMINIVA WW1IWWA I - Vi VAUIIlb. __VARII M•!4_ __ AFAU __ - __ A - ANN A ME - FA"Ilhq -- - . - ___ ______ - NO IN m - WOMEN 00115 A - 0, A S bqhN.- 9 1 WA hW..A M IN FIGURE Gutter and Roadway Discharge -Velocity Chart 3-6 0 Ce, 33°30 - N- Orang e County -------9_ - I- -- 33°30' County of San Diego Hydrology Manual Rainfall Isopluvials 33°15 OCEANSIDE 25 ------------------ 33'15' 100 Year Rainfall Event - 6 Hours lopIuviI (inch) 33eçy -o CD 0 = : 3245 32°45' DPW GIS Sanuis 1 m I \XL Has5 San I)1u,, ( coirc.d' N THIS MAPS PROVIDED WITHOUT WARRANTY OF ANY BIND, EITHER EXPRESS * OR IMPUED, INCLUDING, BUT NOT LIMITED TO. THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Copyrrght SeoGIS eu Rghta Reserved This products may contain rrrforrrratlerr from the SANDAG Reg.orrut E Information System wInch cannot be reproduced without the weSen peorsssroe of SANOAG This product may centarn oformaSoo which has boon oproduced eIh perrrrssror granted by Thomas Brothers Maps S 3 0 3MiIes 32°30 Ce, N- '4-) / Y .z:& x IC 32°30 0 0 10 County of San Diego Orang County --- -Y __________ ______ ____________________ ____________ ____ -. ________ _______ ____ ___ ______- 33°30 Hydrology Manual Riverside County c a c 0 - - RainJ/1 Isopluvials / 'I1I::T 7z:s:: 33 15 — - - - - 3315 100 Year Rainfall Event - 24 Hours OCEANSIDE\ Is 1 -- IsopIuvial (inches) SITE LOCATION ID P24 47 L - CARLSBAD — ' 5 I C) ENCINITAS 7 ' I C) 3300----300 SOLANABEAC -i- I SONY ••\ ----5-O----- — o DEL MA CD CID tNTE I I - A 3245 A2 245 / 0N DPW SID Sanki IS - -. : -- - - - - - - - - - NTHS MAP SPROVIDEO WITHOUT WARRANTY ANY KIND, HTHER XPyFTS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE Copyright SGPJI Rights Reserved. AC IMPERIAL EH - _- t\j't e )( ThisproducN y be I from SANDAG R ___________________ Irrfereroboo Syslero which ,rrrot be reproduced wrtheul the E wrltlee perrro000rr 01 SANDAL - The Product may ceoNih information which has been reproduced roth permission granted by Thomas Brothers Mope 32030 - _______ - _____ -- 32°30 S CD 3 0 3Miies 33°30 Q (A) Orange 33'39 3303Q1 County ) b 0 ) (0) County of San Diego Hydrology Manual IMPERIAL REACH Lo o 3230' - .-.- -------------- ---------- --.-- 32°30' , x± - 1-.... Soil Hydrologic Groups 15' 3°OO' -o CD —' Ic) 0 32°45' OCEANSIDE: E LOCATION CARLSF3AD\ -o O ENCINITAS 0 SOLANABEAC 0 DEL MAR. 0 32°45 ---- - Legend Sil flrniipc Group A Group B Group C LJ Group Undetermined Data Unavailable 0 ( DPW GIS Sa-'MiGIS U Havc San D1L.tt ( ctbLr(.d' N THIS MAP IS PROVIDED WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS * OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 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