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HomeMy WebLinkAboutCDP 16-07; OTA RESIDENCE; HYDROLOGY STUDY FOR 4090 GARIFIELD STREEET CARLSBAD CA 92008; 2017-07-07RECORD COPY Ogft/v»i %I3 Ii7 Initial Date \ © HYDROLOGY STUDY for 4090 GARFIELD STREET CARLSBAD, CA 92008 GDP 16-07 DWG 501-5A GR 201-006 Qty of Cadsbad, CA ± PREPARED FOR: Blair and Paula Ota 4 Bellezza Irvine, CA 92620 Date: July 7, 2017 RECEIVED JUL 1 7 Z017 LAND DEVELOPMENT ENGINEERING I PREPARED BY: Pasco Laret Suiter & Associates 535 N. Highway 101, Suite A Solana Beach, CA 92075 (858) 259-8212 BRIAN ARDOLINO, RCE 71651 y/Nin DATE I I I Ota Residence TABLE OF CONTENTS SECTION ;Executive Summary LO n 'Introduction 1.1 Existing Conditions 1.2 Proposed Project 1.3 1 i 'Snmmflry of Rp.snlts 3nrl Conditions 1.4 Conclusions 1.5 "i 'References 1.6 Methodology 2.0 1 (Introduction 2.1 County of San Di^o Criteria 2.2 - Runoff coefficient determination 2.3 ) Hydroiogic Analyses 3.0 Pre-Developed Hydroiogic Analysis 3.1 f' ; J Post-Developed Hydroiogic Analysis 3.2 Hydraulic Calculations 4.0 1 U -Appendix 5.0 July 2017 *— Ota Residence L 1.0 EXECUTIVE SUMMARY j 1.1 Ititroduction This Hydrology Stxidy for the Ota Residence project has been prepared to analyze the I I hydrologic and hydraulic characteristics of the^eixisting and proposed project site. This 1 report intends to present both the methodolog^and the calculations used for determining the runoff from the project site in both th^pre-developed (existing) conditions and the post-I , developed (propose^ conditions produem by the 100 year 6 hour storm. In addition thisreport will propose the sizing of all^'^essary storm drain facilities and storm drain piping necessary for the storm drain syst^ to safely convey the runoff from the 100-year rainfallI j event u' 1.2 Existing Conditions ^ - The property is geographically located at N 33°^^5.19" W 117°20'26.55". The site is bordered by residential development to the nMfli and south and east Garfield Street is I located to the west of the proposed developn^t. The project site is located in the Agua t - Hedionda Hydrologic Area and more specifically, the Los monos Sub-Area (904.31). r The existing project site includes 1 r^idence, detached garage and associated paving and hardscape. The site consists mostly^f a gentle slope from the southeast to northwest Drainage from the existing site sheet flows in the westerly direction onto Garfield Street I I The runoff is then conveyed nofih along the curb and gutter toward existing curb inlets in Date Avenue and ultimately discharges west into the Agua Hedionda Lagoon. ^ JI 1.3 Proposed Project ^ The intent of the proposed project is to construct 1 newj^aingle family residence with0 associated hardscape improvements and driveways. //The proposed drainage design generally conveys rupoff from the east to the west to I landscape BMP planter areas for LID storm watefi treatment Storm water is collectedL throughout the site into PVC stormdrain systen^^hat either convey the water north, or south, to LID BMP planter areas. The belo^vgrade lightwells and driveway drain to a j f separate PVC pipe system that drains to the garage and into a pump that discharges to the I—' LID BMP planter area along the west side pf the property. Once treated, the water either infiltrates or is discharged through curb underdrains onto Garfield Street as it does in theDO O y/ 1 existing condition. m [/We believe the proposed storm drain system will not adversely affect the downstream system j [ negatively. n jA/.To address the storm water qMhty goals established for this development, proposed permanent Best Management^factice (BMP) and treatment methods wiU be incorporated ' into the storm water runofjW^s'ign. The proposed BMP's include multiple landscape BMP planter areas, which are intprided to mitigate peak flows as well as serve as settling basins. Ti ^ July 2017 Ota Residence f I I i u_, 1.4 Summary of Results Upon performing hydrologic analysis of the project'iite in both the proposed developed and existing condition the following results were produced. One discharge point was analyxed. In the pre-developed condition one discharge point was analyxed. Oudet point indicates that the 100-year peak flow is 0.54 cfs with a rime of concentration of 5 min based on an area of 0.11 AC. In the post-developed condition onfe dischaige point was analyzed. Outlet point indicates that the 100-year peak flow is 0.56 cfs with a time of concentration of 5 min based on an areaofO.ll AC. / / . . . ....The small increase in peak flow leaving the site is due to the small increase in impervious area from existing to proposed condition. The subsequent 11 CF increase in 100-year peak flow attenuation is mitigated^by the on-site LID BMP planter areas. See Sections 3.0 and 4.0 for calculations. (j L5 Conclusions The overall peak flow leaving the property is increased by 0.02 cfs due to the increase in impervious area. The existing drainage patterns of the site will not be significantly altered as a result of the proposed development and the existing site runoff points are to be maintained in the post developed site condition. The LTD planter areas proposed are adequately designed to treat the runoff from the imperviqm material and the volume of storage is sized to mitigate the slight increase in peak runofLfeom the site. Based on the discussion in this report it isThe professional opinion of Pasco Laret Suiter &Associates, Inc. that the existing draina^ system on the corresponding Preliminary Grading ; ' Plan wiU function to adequately intercept, contain and convey flow to the appropriate points of discharge. See Sections 3.0 and 4.(Tfor calculations. I L6 References "San Die^ County Hydrology Manual", revised June 2003, County of San Diego, Department of 1 f PubHc Works, Flood Control Section. 'California Regnal Water Quality Control Board Order No. 2009-0009-DWQ," California Regional Water Control Board, San Diego Region (SDRWQCB). July 2017 •1 * ^ Ota Residence t i 2.0 METHODOLOGY 2.1 Inttoduction L" The hydiologic model iised to perform the hydrologic analysis presented in this report utilizes the Flation Method (RM) equation, Q=CIA. The Rt^ formula estimates the peak \... rate of runoff based on the variables of area, runoff coeffic^nt, and rainfall intensity. The rainfall intensity (I) is equal to: / i", I = 7.44 X Pfi X / 1_' Where: I = Intensity (in/hr) ' j ' Pe = 6-hour precipitation (inches) D = duration (minutes - use;'^c) / Using the Time of Concentration (Tc), which ^ 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 f ! storm water runoff rate (Q) for a given basin in terms of flow (typically in cubic feet per f . second (cfs) but sometimes as gallons per rninute (gpm)). The RM equation is as follows: ' , Q = CIA / ^ ' Where: / Q= flow (in cfs) ] C = runoff coefficient.^^ r i i ) I C = runoff coeffidentj^tatio of rainfall that produces storm water 1 ^ i . - f ^ L., LJ runoff (runoff vs. infiltration/evaporation/absorption/etc) I = average rainfall iniensity for a diuration 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 me storm event being analyzed delivers predpitation to the entire basin uniformly, and therefore the peak discharge rate will occur when a raindrop falls at the most remote portion qi the basin arrives at the point of analysis. The RM also assumes that the fraction of raWaH that becomes runoff or the runoff coeffident C is not affected by the storm intensity, I, or the predpitation zone number. ) ' In addition to the above E^jtion Method assumptions, the conservative assumption that all nmoff coeffidents utilized for this report are based on type "D" soils. 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 th^^ hydrologic characteristics of basins up to approximately one square mile in size. /The Cotmty of San Diego has developed its own tables, nomographs, and methodologi^ for analyzing storm water runoff for areas within the cotmty. The Cotmty has also dev^ped predpitation isopluvial contour maps that show even Unes of rainfall anticipated firon^ given storm event (Le. 100-year, 6-hour storm). July 2017 Ota Residence One of the variables of the RM equation is the runoff co^&cient, C. The runoff coefficient ^ is dependent only upon land use and soil type and the ^unty of San Diego has developed a j j table of Runoff Coefficients for Urban Areas to l^'^applied to basin located within the County of San Diego. The table categori2es the/land use, the associated development density (dwelling units per acre) and the percei^tage of impervious area. Each of the '' categories listed has an associated nmoff coeffiaent, C, for each soil type class. 1. 1 I I . ,/Cn. i D i j 1 Li 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 (FtAA) overland time of flow equation. This equation essentially limits the flow path length for the initiaEtime of concentration to lengths of 100 feet or less, and is dependent on land use and slopq^ 2,3 Runoff Coefficient Determination As stated in section 2.2, the runoff coefficient is^ependent upon land use and soil type and the County of San Diego has developed a taWe of Rtmoff Coefficients for Urban Areas to 1 be apphed to basin located within the County of San Diego. The table, included at the end of this section, categorizes the land use, associated development density (dwelling units per acre) and the percentage of impervious area. The runoff coefficient can be calculated for an area based on soil type and impervious percentage using the equation found in section 3.1.2 of the County Hydrology ManualySee Sections 3.0 and 5.0 for Coefficient Table and C Value Calculations on the Pre and Po^Development Maps. July 2017 , 1 !j ("< 1 I Ota Residence 3.0 HYDROLOGIC ANALYSES Rational Method Pflfametpfs j i' Runoff Coefficient C= 0.9 x (% Impervious) + Cp (1-% Impervious)* Cp=0.25* for existing condition pervious type "B" soils /f 1 100 Year 6 Hour Storm Precipitation (P6)=2.5 in (see rainfall isopluvial*) Tc=(11.9L3/AE)0.385 per Figure 3-4 of the County of San Diego Hydrology Manual (L=miles)* n Tt=Ti + Tc 1= Intensity in/hr, I=7.44xP6xD-0.645* Duration (D)= Time of Concentration, Tc Q=Peak Runoff, Q=C*I*A (cfs) C= (% IMP X 0.87) + [(1-%IMP) X 0.41] f II *From San Diego County Hydrology Manual, June 2003 Revision Section 3 1 J ' 1 1 ' 1 3.1 Pte-Developed Hydtologic Model Output BASIN A=4,995 sf= 0.11 ac Impervious area = 3,762 sf % IMP = 75% C= (0.75x 0.9) + [(1-0.75)0.25] C= 0.74 Tc=(l 1.9(124/5280)3/4.7)0 385 Tc=0.019 hours = 1.1 min 1.1 min < 5 min Tc=5 minutes Iioo=7.44(2.5)(5)-0-645 Iioo==6.59 in/hr Qiixi= (17^^.59 in/hr) 0.11 acres Q]m=0?MVfi3 3.2 Post-Developed Hydtologic Model Ouqjut SUB-AREA 'A' A=l,24« sf= 0.03 ac Impervious area = 973 sf % IMP = 78% C= (0.78x 0.9) -f [(1-0.78)0.25] C= 0.76 t ; Assume Tc=5 minutes Iioo=7.44(2.5)(5)4)-645 Iioo=6.59 in/li Qioo= 0.76(6?39 in/hr) 0.03 acres Qioo=(hl^cfis July 2017 I . .•"n I I 1 I I 1 , 1 UJ Ota Residence I j i % IMP = 100% SUB-AREA 'B' Piimp neBlgfi: Area draining to pump = 754 sf C=0.9 Assume Tc=5 minutes Iioo=7.44(2.5)(5)^-'545 Iioo=6.59 in/bt Pump Qioo— (b^.59 tn/hr) 0.017 acres PunjpsQtS6^(nlO cfis Pump Rate Design: 56 GPM 56 Gal/Min ¨ (1 min/^0/8ecJ^"'(0.13 cf/1 gal) = 0.12 cfe max. n % IMP = 65% Overland Area: A=997 sf=0.02 ac Impervious area = 896 sf % IMP = 90% C= (0.90x 0.9) + [(1-0.90)0.25] C= 0.84 Assume Tc=5 minutes Iioo=7.44(2.5)(5)-o-M5 Iioo=^6.59 in/M Qioo= 0.84(6.59 in/hr) 0.02 acres Qioo=0.11 cfis Sub-area 'B' total Qioo ranges from 0.11 cfe miniiriumto 0.23 cfe (0.11+0.12) maximum when pump is running. SUB-AREA 'O A=l,856 sf=0.04 ac Impervious area = 1,209 sf C= (0.65x 0.9) + [(1-0.65)0.25] C= 0.67 Assume Tc=5 minutes Iioo=7.44(2.5)(5)-o-M5 Iioo=6.59 in/hr Qioo= 0.67(6.59 in/hr) 0.04 acres Qioo~0.18 cfe QIOO = 0.m02Z3+0.18 =0.51^ July 2017 r . Ota Residence I I ! i i r ■n nI • I 0 Ij AQ = Qpost - Qpre = 0.56 cfs - 0.54 cfs = 0.02 cfs July 2017 in L' Rational Method Hydrograph Calculations Pre Developed Condition 4090 Garfleld Street Carlsbad, CA U [j r, b jb 1 : G 0 n 0 1 J p S II 0.54 cfs Tc=5 min C=0.74 #=72 P50,6=2.5 in A=0.11 acres (7.44*P6*D^.645)(I'D/BO)(V1-V0)(AV/AT)(Q=dA)(Re-ordere D 1 VOL AVOL 1 (INCR)Q VOL ORDINA #(MIN)(IN/HR)(IN)(IN)(IN/HR)(CFS)(CP)(CPS) 0 0 0.00 0.00 0.55 6.59 0.54 162 1 5 6.59 0.55 0.15 1.84 0.15 45 0.01 2 10 4.21 0.70 0.11 1.30 0.11 32 0.01 3 15 3.24 0.81 0.09 1.05 0.09 26 0.01 4 20 2.69 0.90 0.07 0.89 0.07 22 0.01 5 25 2.33 0.97 0.06 0.78 0.06 19 0.01 6 30 2.07 t.04 0.06 0.70 0.06 17 0.01 7 35 1.88 1.10 0.05 0.64 0.05 16 0.01 8 40 1.72 1.15 0.05 0.59 0.05 14 0.01 9 45 1.60 1.20 0.05 0.55 0.04 13 0.01 10 50 1.49 1.24 0.04 0.51 0.04 13 0.01 11 55 1.40 1.29 0.04 0.48 0.04 12 0.01 12 60 1.33 1.33 0.04 0.46 0.04 11 0.01 13 65 1.26 1.36 0.04 0.44 0.04 11 0.01 14 70 1.20 1.40 0.03 0.42 0.03 10 0.01 15 75 1.15 1.44 0.03 0.40 0.03 10 0.02 16 80 1.10 1.47 0.03 0.38 0.03 9 0.02 17 85 1.06 1.50 0.03 0.37 0.03 9 0.02 18 90 1.02 1.53 0.03 0.36 0.03 9 0.02 19 95 0.99 1.56 0.03 0.34 0.03 8 0.02 20 100 ,0.95 1.59 0.03 0.33 0.03 8 0.02 21 105 0.92 1.62 0.03 0.32 0.03 8 0.02 22 110 0.90 1.64 0.03 0.31 0.03 8 0.02 23 115 0.87 1.67 0.03 0.31 0.02 7 0.02 24 120 0.85 1.70 0.02 0.30 0.02 7 0.02 25 125 0.83 1.72 0.02 0.29 0.02 7 0.02 26 130 0.81 1.75 0.02 0.28 0.02 7 0.02 27 135 0.79 1.77 0.02 0.28 0.02 7 0.02 28 140 0.77 1.79 0.02 0.27 0.02 7 0.02 29 145 0.75 1.81 0.02 0.26 0.02 6 0.02 30 150 0.73 1.84 0.02 0.26 0.02 6 0.02 31 155 0.72 1.86 0.02 0.25 0.02 6 0.02 32 160 0.70 1.88 0.02 0.25 0.02 6 0.02 33 165 0.69 1.90 0.02 0.24 0.02 6 0.02 34 170 0.68 1.92 0.02 0.24 0.02 6 0.03 35 175 0.66 1.94 0.02 0.23 0.02 6 0.03 36 180 0.65 1.96 0.02 0.23 0.02 6 0.03 37 185 0.64 1.98 0.02 0.23 0.02 6 0.03 38 190 0.63 2.00 0.02 0.22 0.02 5 0.03 39 195 0.62 2.02 0.02 0.22 0.02 5 0.03 40 200 0.61 2.03 0.02 0.21 0.02 5 0.04 41 205 0.60 2.05 0.02 0.21 0.02 5 0.04 2493 Pre Hydrograph 5/8/2017 r^.Li1Rational Method Hydrograph CalculationsPre Developed Condition4090 Garfield Street Carlsbad, CAu422100.592.070.020.210.0250.04432150.582.090.020.210.0250.05442200.572.100.020.200.0250.05452250.572.120.020.200.0250.06462300.562.140.020.200.0250.07r~\472350.552.150.020.190.0250.11482400.542.170.020.190.0250.15iJ492450.542.190.020.190.0250.54n502500.532.200.020.190.0250.09512550.522.220.020.180.0140.06522600.522.230.020.180.0140.04532650.512.250.010.180.0140.04r542700.502.260.010.180.0140.03552750.502.280.010.180.0140.03562800.492.290.010.170.0140.03r~I572850.492.310.010.170.0140.02; 1•i '582900.482.320.010.170.0140.02—'592950.472.330.010.170.0140.02603000.472.350.010.170.0140.02! I613050.462.360.010.160.0140.02623100.462.380.010.160.0140.02633150.462.390.010.160.0140.02n643200.452.400.010.160.0140.02653250.452.420.010.160.0140.02663300.442.430.010.160.0140.01673350.442.440.010.150.0140.01!683400.432.450.010.150.0140.01693450.432.470.010.150.0140.01-r~;703500.432.480.010.150.0140.01713550.422.490.010.150.0140.01723600.422.510.000.000.0000.011SUM=5050.01cubic feeacre-feeto1.3nL J/'ILi2493 Pre Hydrograph5/8/2017 n n Rational Method Hydrograph Calculations Pre Developed Condition 4090 Garfield Street Carlsbad, CA iJ u n u a 0 0 n u n 1 u n u p \ ij 0 0 G 0.60 0.50 0.40 •§ 0.30 0.20 0.10 0.00 RM-HYDROGRAPH Project Time (min) 400 2493 Pre Hydrograph 5/8/2017 I ,1"'Rational Method Hydrograph CalculationsPost Developed Condition4090 Garfield Street Carlsbad, CAuQioo-Tc=0.565cfsminC=0.75n1 r#=72Pso.s"2.5inA=0.11acres(7.44*P6*D''-.645)(l*D/<60)(V1-V0)(A WAT)(Q=clA)(Re-ordemD1VOLAVOL1 (INCR)QVOL0RDINA1i;#(MIN)(IN/HR)(IN)(IN)(IN/HR)(CFS)(OF)(CFS)000.000.000.556.590.56168156.590.550.151.840.15450.01n2104.210.700.111.300.11320.011U..'3153.240.810.091.050.09260.014202.690.900.070.890.07220.01r,5252.330.970.060.780.06190.011 j6302.071.040.060.700.06170.017351.881.100.050.640.05160.01r~,8401.721.150.050.590.05150.011 19451.601.200.050.550.05140.01—-10501.491.240.040.510.04130.0111551.401.290.040.480.04120.01, i12601.331.330.040.460.04110.0113651.261.360.040.440.04110.0114701.201.400.030.420.03100.011 !15751.151.440.030.400.03100.02[J16801.101.470.030.380.0390.0217851.061.500.030.370.0390.0218901.021.530.030.360.0390.02i ;19950.991.560.030.340.0390.02201000.951.590.030.330.0380.02211050.921.620.030.320.0380.02221100.901.640.030.310.0380.02I (231150.871.670.030.310.0380.02241200.851.700.020.300.0270.02251250.831.720.020.290.0270.02261300.811.75. 0.020.280.0270.02271350.791.770.020.280.0270.02P281400.771.790.020.270.0270.02ij291450.751.810.020.260.0270.02301500.731.840.020.260.0260.02311550.721.860.020.250.0260.02j ,321600.701.880.020.250.0260.02L)331650.691.900.020.240.0260.03n341700.681.920.020.240.0260.03351750.661.940.020.230.0260.03( i361800.651.960.020.230.0260.03371850.641.980.020.230.0260.03r'^381900.632.000.020.220.0250.03Ij391950.622.020.020.220.0250.03402000.612.030.020.210.0250.04r~.412050.602.050.020.210.0250.04f-2493 Post Hydrograph5/8/2017 Rational Method Hydrograph Calculations Post Developed Condition 4090 Garfield Street Carlsbad, CA LJ 42 210 0.59 2.07 0.02 0.21 0.02 5 0.04 43 215 0.58 2.09 0.02 0.21 0.02 5 0.05 f 44 220 0.57 2.10 0.02 0.20 0.02 5 0.05 45 225 0.57 2.12 0.02 0.20 0.02 5 0.06 '—• 46 230 0.56 2.14 0.02 0.20 0.02 5 0.07 ra 47 235 0.55 2.15 0.02 0.19 0.02 5 0.11 I 48 240 0.54 2.17 0.02 0.19 0.02 5 0.15 49 245 0.54 2.19 0.02 0.19 0.02 5 0.56 50 250 0.53 2.20 0.02 0.19 0.02 5 0.09 1 51 255 0.52 2.22 0.02 0.18 0.02 5 0.06 1 52 260 0.52 2.23 0.02 0.18 0.01 4 0.05 53 265 0.51 2.25 0.01 0.18 0.01 4 0.04 r 54 270 0.50 2.26 0.01 0.18 0.01 4 0.03 1 55 275 0.50 2.28 0.01 0.18 0.01 4 0.03 56 280 0.49 2.29 0.01 0.17 0.01 4 0.03 1 57 285 0.49 2.31 0.01 0.17 0.01 4 0.02 I '58 290 0.48 2.32 0.01 0.17 0.01 4 0.02 -59 295 0.47 2.33 0.01 0.17 0.01 4 0.02 60 300 0.47 2.35 0.01 0.17 0.01 4 0.02 61 305 0.46 2.36 0.01 0.16 0.01 4 0.02 62 310 0.46 2.38 0.01 0.16 0.01 4 0.02 63 315 0.46 2.39 0.01 0.16 0.01 4 0.02 64 320 0.45 2.40 0.01 0.16 0.01 4 0.02 65 325 0.45 2.42 0.01 0.16 0.01 4 0.02 66 330 0.44 2.43 0.01 0.16 0.01 4 0.02 67 335 0.44 2.44 0.01 0.15 0.01 4 0.01 j '68 340 0.43 2.45 0.01 0.15 0.01 4 0.01 69 345 0.43 2.47 0.01 0.15 0.01 4 0.01 -70 350 0.43 2.48 0.01 0.15 0.01 4 0.01 '71 355 0.42 2.49 0.01 0.15 0.01 4 0.01 --72 360 0.42 2.51 0.00 0.00 0.00 0 0.01 SUM=516 0.01 cubic feel acre-feet 2493 Post Hydrograph 5/8/2017 Rational Method Hydrograph Calculations Post Developed Condition 4090 Garfield Street Carlsbad, CA L r-'1 ; L-J 0.60 0.50 0.40 "§ 0.30 0.20 0.10 0.00 RM-HYDROGRAPH Project 1 - * ►y _| , , , 1 1 , , , L__| , , 1 , , 1 , , . . 1 50 100 150 200 250 Time (min) 300 350 400 u 2493 Post Hydrograph 5/8/2017 '—' Ota Residence 1 I . r'^ 4.0 HYDRAULIC CALCULATIONS Detention Rasin Siring; LID BMP Sizing Requitement T.TD BMP area requited is equal to 4% of the impervious are being removed and replaced or added Required BMP = 0.04 (3,861 sf) = 155 SF Proposed BMP Area = 159 SF Proposed BMP Area > Required BMP Area Detention Volume Sizing Required 100 year Storage Volume = 516 cf — 505 of = Ucf Proposed BMP area = 159 sf Ponding Depth = 3 inches (0.25 ft) Engineered Soil Layer =12 inches (1 ft) Void Ratio Factor = 0.4 Proposed Storage Volume = (159 sf x 0.25 ft) + (159 sf x 1 ft x 0.4) = 39 cf + 63 cf = 102 cf Proposed Storage Volume > Required Storage Volume July 2017 I L Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3ID® t)y Autodesk, inc.Monday, May 8 2017 SUB-AREA A OUTLET L- r Circular Diameter (ft) Invert Elev (ft) Slope (%) N-Value Calculations Compute by: Known Q (cfs) = 0.25 = 45.96 = 1.50 = 0.009 Known Q = 0.15 Highiighted Depth (ft) Q(cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Grit Depth, Yc (ft) Top Width (ft) EGL (ft) 0.20 0.150 0.04 3.56 0.55 0.23 0.20 0.40 L-' 1 n < > Elev (ft) 47.00 - 46.50 46.00 45.50 45.00 Section Reach (ft) ' I Channel Report u_ Hydraftow Express Extension for Autodesk® AutoCAD® CM! 3D® by Autodesk, Inc. SUB-AREA B OUTLET Monday, May 8 2017 LJ L; n Circular Diameter (ft) Invert Elev (ft) Slope (%) N-Value Calculations Compute by: Known Q (cfs) = 0.25 = 46.22 = 3.00 = 0.009 Known Q = 0.23 Highlighted Depth (ft) Q(cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Grit Depth, Yc (ft) Top Width (ft) EGL (ft) 0.22 0.230 0.05 5.03 0.61 0.24 0.16 0.61 V. J J 1 ! \ r ij n Elev (ft) 47.00 - 46.75 46.50 46.25 46.00 45.75 Section Reach (ft) Channel Report L, Hydraflow Express Extension for Autodesk® AutoCAD® Ch/l! 3D® tjy Autodesk, Inc. SUB-AREA C OUTLET Circular Diameter (ft) Invert Elev (ft) Slope (%) N-Value Calculations Compute by: Known Q (cfs) L-' r; 1 I r". \ ' r": i i Elev (ft) 47.00 - 46.75 46.50 46.25 46.00 = 0.25 = 46:45 = 2.00 = 0.009 Known Q = 0.18 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Grit Depth, Yc (ft) Top Width (ft) EGL (ft) Monday, May 8 2017 0.21 0.180 0.04 4.09 0.58 0.24 0.18 0.47 : \i V J Ota Residence 5.0 APPENDIX July 2017 33' 8' 46" N 33' 8'44"N Hydrologic Soil Group-San Diego County Area, California MapScale: 1:260f~onApcro&(8S'x ll")sheet 0 -------========---------------===============ilMetes 21 N 3 7 14 A ------=========------------=:=:::=:::=:::=:::=::~lfeet o ro ~ ~ oo Map projection: Web Mertatllr C.omer axininates: WGS84 Edge tics: UTM Z.one 11N WGS84 USDA Natural Resources Web Soil Survey National Cooperative Soil Survey .iiiiliii Conservation Service 3/31 /2017 Page 1 of 4 33' 8' 46" N 33' 8'44"N Hydrologic Soil Group-San Diego County Area, California MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soll Rating Polygons D A D AID D B D BID D C D CID D D D Not rated or not available Soll Rating Lines _,,. A _,,. AID _,,. B _,,. BID _,,. C _,,. CID _,,. D .. " Not rated or not available Soll Rating Points • A • AID • B • BID USDA Natural Resources --Conservation Service • C • CID • D a Not rated or not available Water Features Streams and Canals Transportation +++ Rails _,_ Interstate Highways _,_ US Routes ---Major Roads Local Roads Background • Aenal Photography Web Soil Survey National Cooperative Soil Survey 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 10, Sep 12, 2016 Soil map units are labeled (as space allows) for map scales 1 :50,000 or larger. Date(s) aerial images were photographed: Nov 3, 2014-Nov 22,2014 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. 3/31/2017 Page 2 of 4 Hydrotogic Soil Group—San Diego County Area, Callfomia Hydrologic Soil Group n L: r; I L. Hydrologic Soil Group— Sumntaiy by Map Unit — San Diego County Area, California (CA638) Map unK.symbol Map unit name Rating Acres In AOI Percent of AOI : MIC Marina loamy coarse sand, 2 to 9 percent slopes B 0.1 n 100.0% Totals for Area of Inters 0.1 100.0% n 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, we|l drained to excessively drained sands or graveily sands. These soils have a high rate of water transmission. I. 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 weL These consist chiefly of days that have a high shrihk-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 dasses. Rating Options Aggregation Method: Dominant Condition Natural Resources Conservation Service Web Soli Survey Natlpnal Cooperative Soil Survey 3/31/2017 Page 3 of 4 Hydrologlc Soil Group—San Diego County Area, CaDfomia I ' / L Component Percent Cutoff: None Specified Tie-break Rule: Higher Natural Resources Conservation Service Web Soil Survey Nationai Cooperative Soil Survey 3/31/2017 Page 4 of 4 r: San Diego County Hydrology Manual Date: June 2003 Section: Page: 3 6 of 26 Table 3-1 RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use Runoff Coefficient "C" Soil Type NRCS Elements County Elements %IMPER.A B C D Undisturbed Natural Terrain (Natural)Permanent Open Space 0*0.20 035 030 0.35 Low Density Residential (LDR)Residential, 1.0 DU/A or less 10 037 032 036 0.41 Ix)w Density Residential (LDR)Residential, 2.0 DU/A or less 20 034 038 0.42 0.46 Low Density Residential (LDR)Residential, 2.9 DU/A or less 25 038 0.41 0.45 0.49 Medium Density Residential (MDR)Residential, 43 DU/A or less 30 0.41 0.45 0.48 0.52 Medium Density Residential (MDR)Residential, 73 DU/A or less 40 0.48 031 0.54 0.57 Medium Density Residential (MDR)Residential, 10.9 DU/A or less 45 032 0.54 0.57 0.60 Medium Density Residential (MDR)Residential, 14.5 DU/A or less 50 035 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. Com)Neighborhood Commercial 80 0.76 0.77 0.78 0.79 Commercial/Industrial (G. Com)General Commercial 85 0.80 0.80 0.81 0.82 Commercial/Industrial (O J. Com)Office Professional/Commercial 90 0.83 0.84 0.84 0.85 Commercial/Industrial (Limited I.)Limited Industrial 90 0.83 0.84 0.84 0.85 Commercial/Industrial (General I.)General Industrial 95 0.87 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 33^15 m ENCINIT 4 1 92 "45 County of San Diego Hydrology Manual Rainfall Isopluvials 100 Year Rainfall Event - 6 Hours Isopluvial (inches) s^gis 9wsm#ic tiiroi^cr Semcw We Have San THH IMP t8 PROVDG) WTTHOOT WARR/WTY OF ANY KIND. BTiei EXPREB8 OR (MPLE). NCUJOWO, BOT NOT IJMnH)TO.-mE IAJB3 WARRMniES OF ieV>tANTAaUTY AND FTTNEBS FOR A PARTICULAR PUiV*OeE. CiJwM* Al Rlqhti riMTiwd "ihh produt* mi|r oorttin IrtonWIon txm •* 8/WIW3 ReglonN MviraODn 8)«taa wftoh QBvwt be raproduoad vritvut the wrtNn paneMon of &ANDAO. TNa pndJOt nay ovMi HbrnwHon vMcti haa baan ripreduoad Hftipanriiaiicii by Thomaa BmCiaia Mipa. 3 Miles I I I I I I I I l~n Q1oa=of 54 CFS I (, \\',\ / I -1 '\ I I I \ I rr I I' I ) " ( BASI~\ HYDROLOG/C NODE MAP 4090 GARFIELD STREET PRE-DEVELOPMENT MAP ! \ ,\'il-/~-t---~~ ........ ~-........ ----/~-~ Ml ...... LEGEND BASIN BDI..NJARY FLOW LUE Il4'ERVIOUS AREA -C-CALCULATIONS 3,762 SF PER CDLNTY HYDROLOGY MANUAL 3.1..2 C• 0.9 x (% IW'ERVIOUS) + Cp x (1.-% IH'ERVIOUS) Cp = 0.25 FOR TYPE B ' SOIL c-(O. 75x0 .9) + (0 .25x0 .25) C-0.74 SCALE: 1 •=20' [ I I I I -48.J Qjoo-!.}5 CFS I l\ EL-48.4 (1100-0 .23 ~S MAX =48.63 G100-0. 8 CFS I \ w -0 a.NB B J.751 SF (OJU AQ (>,().86 ' --- HYDROLOG/C NODE MAP 4090 GARFIELD STREET POS~DEVELOPMENTMAP BASIN AREA=4.995 SF (0.11 AC) I I I I \,,,,...,., HIGH POCT EL=52.9 f" I I I ,,,,..... I I I I I I I LEGEND BASIN 8Dt.NJARY SLf3-AREA BOtNJARY - - - FLOW LYE If.f'ERVIOUS AREA -C-CALCULATIONS 3.861. SF PER COUNTY HYlflOLOGY MANUAL 3 .12 C= 0.9 x (% IMPERVIOUS) + Cp x (1-% IMPERVIOUS) Cp = 0 .25 FOR TYPE B' SOIL SUB-AFEA A C= (0.78x 0.9) + [ (1-0.78)x0.25) C=0.76 SUB-AFEA B C= (0.94x 0.9) + [ (1-0.94)x0.25) C=0.86 SLf3-AFEA C C= (0 .67x O .9) + [ ( 1-0 .67)x0 .25) C=0.68 BASIN C= (0 .77x 0.9) + [ (1-0.77)x0.25) C=0.75 SCALE: 1•=20'