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Home My WebLink AboutCDP 2017-0069; CIARMOLI RESIDENCE; HYDROLOGY REPORT; 2018-12-20I I I I I HYDROLOGY STUDY for 4205 SKYLINE ROAD CARLSBAD, CA 92008 City of Carlsbad, CA I PREPARED FOR: Dino & Susan Ciarmoli I 4205 Skyline Road Carlsbad, CA 92008 I Date: December 20, 2018 Revised: I MAY 16 2019 PREPARED BY: LAND DEVELOPMENT I. Pasco Laret Suiter & Associates ENGINEERI NG 535 N. Highway 101, Suite A Solana Beach CA 92075 I (858) 259-8212 7 OFESSi I I ! 6QBRIAN ARDOL NO, RCE 71651 DATE I I Pritchard Residence I TABLE OF CONTENTS SECTION Executive Summary 1.0 Introduction 1.1 Existing Conditions 1.2 Proposed Project 1.3 Summary of Results and Conditions 1.4 Conclusions 1.5 References 1.6 Methodology 2.0 Introduction 2.1 County of San Diego Criteria 2.2 Runoff coefficient determination 2.3 Hydrologic Analyses 3.0 Pre-Developed Hydrologic Analysis 3.1 Post-Developed Hydrologic Analysis 3.2 Hydraulic Calculations 4.0 Appendix 5.0 I I I I 1 I 2 June 2017 I I I I I I I 1 I 1 Pritchard Residence I 1.0 EXECUTIVE SUMMARY 1.1 Introduction I This Hydrology Study for the Ciarmoli Residence project 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 I 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 I necessary for the storm drain system to safely convey the runoff from the 100-year rainfall event. 1.2 Existing Conditions The property is geographically located at N 3309'9.50" W 117°19'9.63". The site is bordered I by residential development to the east and south and MacArthur Ave. to the north and Skyline Road to the west. The project site is located in the Agua Hedionda Hydrologic Area and more specifically, the Los monos Sub-Area (904.31). The existing project site includes an existing single-family residence, driveway, and associated landscaping. The site consists mostly of a gentle slope from the east to west. Drainage from I the existing site sheet flows in the westerly direction. The runoff is then conveyed through rolled curb & gutter to an existing cross gutter located just west of the site. Ultimately the cross-gutter discharges west into the Pacific Ocean. 1.3 Proposed Project The intent of the proposed project is to construct a non-habitable accessory unit with hardscape and landscape improvements. The proposed drainage design conveys runoff from the east to the west to two drywells at I the southern property line. Once captured, the water is discharged through a gravel spreader at the rear of the property as it does in the existing condition. We believe the proposed storm drain system will not adversely affect the downstream system negatively. To address the storm water quality goals established for this development, proposed permanent Best Management Practice (BIV[P) and treatment methods will be incorporated into the storm water runoff design. The proposed BMP's include multiple landscape BMP planter areas, which are intended to mitigate peak flows as well as serve as settling areas. I I June 2017 1 I Pritchard Residence I 1.4 Summary of Results Upon performing hydrologic analysis of the project site in both the proposed developed and existing condition the following results were produced. One discharge point was analyzed. In the pre-developed condition one discharge point was analyzed. Outlet point indicates that the 100-year peak flow is 1.30 cfs based on an area of 0.48 AC. In the post-developed condition one discharge point was analyzed. Outlet point indicates that the 100-year peak flow is 1.36 cfs based on an area of 0.48 AC. 1.5 Conclusions The overall peak flow leaving the property increased by 0.06 cfs. Based on the discussion in this report it is the professional opinion of Pasco Laret Suiter & ' Associates, Inc. that the proposed drainage system on the corresponding Grading Plan will function to adequately intercept, contain and convey flow to the appropriate points of discharge. See Sections 3.0 and 4.0 for calculations. 1.6 References I "San Diego County Hydrology Manual", revised June 2003, County of San Diego, Department of Public Works, Flood Control Section. "California Regional lVaterQualiy Control Board Order No. 2009-0009-D WQ, "California I Regional Water Control Board, San Diego Region (SDRWQCB). U I I I I I 4 June 2017 I I Pritchard Residence 2.0 METHODOLOGY 2.1 Introduction 1 The hydrologic model used to perform the hydrologic analysis presented in this report utilizes the Ration Method (RM) equation, Q=C1A. The RM formula estimates the peak rate of runoff based on the variables of area, runoff coefficient, and rainfall intensity. The I rainfall intensity (I) is equal to: I =7.44 x P6 x D °645 Where: I I = Intensity (in/hr) Po = 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 I 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. I 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 falls at the most remote portion of the basin arrives at the point of analysis. The RIVI also I 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. I In addition to the above Ration Method assumptions, the conservative assumption that all runoff coefficients utilized for this report are based on type "D" soils. I Rational Method calculations were performed using the AES 2010 computer program. To perform the hydrology routing, the total watershed area is divided into sub-areas which discharge at designated nodes. The procedure for the sub-area summation model is as I follows: Subdivide the watershed into an initial sub-areas and subsequent sub-areas, which are generally less than 10 acres in size. Assign upstream and downstream I node numbers to each sub-area. Estimate an initial T. by using the appropriate nomograph or overland flow velocity estimation. The minimum T considered is 5.0 minutes. I (3) Using the initial T, determine the corresponding values of I. Then Q = CIA. June 2017 1 I Pritchard Residence I (4) Using Q, estimate the travel time between this node and the next by Manning's equation as applied to particular channel or conduit linking the two nodes. Then, repeat the calculation for Q based on the revised intensity (which is a function of the revised time of concentration) I 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 KM 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. 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 of 100 feet or less, and is dependent on land use and slope. 2.3 Runoff Coefficient Determination As stated in section 2.2, the runoff coefficient is dependent 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. Low Density Residential coefficient of 0.41 was used for pervious area, and Commercial/ Industrial coefficient of 0.87 was used for impervious area. Weighted runoff coefficients for onsite areas were calculated using the existing and proposed impervious area for each basin. See Appendix 5.0 for Coefficient Table and C Value Calculations on the Pre and Post Development Maps. June 2017 6 I Pritchard Residence I 3.0 HYDROLOGIC ANALYSES Rational Method Parameters I Runoff Coefficient C= 0.9 x (% Impervious) + Cp (1-% Impervious)* Cp0.25* for existing condition pervious type "B" soils 100 Year 6 Hour Storm Precipitation (P6)2.5 in (see rainfall isopluvial*) Tc(11.9L3/iE)0.385 per Figure 3-4 of the County of San Diego Hydrology Manual (Lmiles)* I TtTi + Tc 1= Intensity in/hr, I=7.44xP6xD0,645* 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 BASIN A20,727 sf = 0.48 ac I Impervious area = 4,954 sf % IMP = 24% C= (0.24x 0.9) + [(1-0.24)0.25] I C= 0.41 A0.48 ac I C=0.41 L=180 if EH=22' Tc[11.9(L/Mi)3/iH]03 .016 hours =0.96 minutes < 5 mins use 5 mins to calculate I I I=7.44xP6xD-0645 6.59 in/hr Qioo= 0.41 * 6.59 in/hr * 0.48 acres Qi00=1.30 cfs 3.2 Post-Developed Hydrologic Model Output BASIN I A20,727 sf= 0.48 ac Impervious area = 5,735 sf % IMP = 28% I C= (0.28x 0.9) + [(1-0.28)0.25] C= 0.43 A=0.48 ac C=0.43 L=347 if H= 13.5' Tc[11.9(L/Mi)3/LH]038S.04 hours =2.46 minutes < 5 mins - use 5 mins to calculate I I7.44xP6xD 0645 6.59 in/hr Qioo 0.43 * 6.59 in/hr * 0.48 acres Qioo1.36 cfs 1 June 2017 7 I I Pritchard Residence I 3.3 Dry Well Sizing Proposed dry well area = 24 sf Gravel layer = 54 inches (4.5 ft 1 Void ratio = 0.4 Proposed Storage Volume = 2 (24 sfx 4.5 ft. x 0.4) 11 = 86.4 cf (86 cf required) I I I I I I I I I I II June 2017 8 I Pritchard Residence 4.0 HYDRAULIC CALCULATIONS I Li LII I I I I I I I I I June 2017 vt I I Rational Method Hydrograph Calculations for 4205 Skyline Road, Carlsbad, CA (Pre-developed condition) I Q100 1.3 cfs U Tc= 5 min C= 0.41 #= 72 P106= 2.5 in A= 0.48 acres (744*P6*DA 645) (I*D/60) (VI-VO) (A VIA 7) (Q=ciA) (Re-ordered) I D I VOL zW OL I(INCR) Q VOL ORDINATE # (MIN) (IN/HR) (IN) (IN) (IN/HR) (CF S) (CF) (CFS) 0 0 0.00 0.00 0.55 6.59 1.30 390 5 6.59 0.55 0.15 1.84 0.36 108 0.03 I i 2 10 4.21 0.70 0.11 1.30 0.26 77 0.03 3 15 3.24 0.81 0.09 1.05 0.21 62 0.03 4 20 2.69 0.90 0.07 0.89 0.17 52 0.03 I 5 25 2.33 0.97 0.06 0.78 0.15 46 0.03 6 30 2.07 1.04 0.06 0.70 0.14 41 0.03 7 35 1.88 1.10 0.05 0.64 0.13 38 0.03 1 840 1.72 1.15 0.05 0.59 0.12 35 0.03 9 45 1.60 1.20 0.05 0.55 0.11 32 0.03 10 50 1.49 1.24 0.04 0.51 0.10 30 0.03 55 1.40 1.29 0.04 0.48 0.10 29 0.03 I ii 12 60 1.33 1.33 0.04 0.46 0.09 27 0.03 13 65 1.26 1.36 0.04 0.44 0.09 26 0.04 14 70 1.20 1.40 0.03 0.42 0.08 25 0.04 I 15 75 1.15 1.44 0.03 0.40 0.08 24 0.04 16 80 1.10 1.47 0.03 0.38 0.08 23 0.04 17 85 1.06 1.50 0.03 0.37 0.07 22 0.04 18 90 1.02 1.53 0.03 0.36 0.07 21 0.04 I 19 95 0.99 1.56 0.03 0.34 0.07 20 0.04 20 100 0.95 1.59 0.03 0.33 0.07 20 0.04 I 21 22 105 110 0.92 0.90 1.62 1.64 0.03 0.03 0.32 0.31 0.06 0.06 19 19 0.04 0.04 23 115 0.87 1.67 0.03 0.31 0.06 18 0.04 24 120 0.85 1.70 0.02 0.30 0.06 18 0.04 25 125 0.83 1.72 0.02 0.29 0.06 17 0.05 I 26 130 0.81 1.75 0.02 0.28 0.06 17 0.05 27 135 0.79 1.77 0.02 0.28 0.05 16 0.05 28 140 0.77 1.79 0.02 0.27 0.05 16 0.05 I 29 145 0.75 1.81 0.02 0.26 0.05 16 0.05 30 150 0.73 1.84 0.02 0.26 0.05 15 0.05 31 155 0.72 1.86 0.02 0.25 0.05 15 0.06 ' 32 160 0.70 1.88 0.02 0.25 0.05 15 0.06 33 165 0.69 1.90 0.02 0.24 0.05 14 0.06 34 170 0.68 1.92 0.02 0.24 0.05 14 0.06 35 175 0.66 1.94 0.02 0.23 0.05 14 0.07 I 36 180 0.65 1.96 0.02 0.23 0.05 14 0.07 37 185 0.64 1.98 0.02 0.23 0.04 13 0.07 38 190 0.63 2.00 0.02 0.22 0.04 13 0.08 I 39 195 0.62 2.02 0.02 0.22 0.04 13 0.08 40 200 0.61 2.03 0.02 0.21 0.04 13 0.09 41 205 0.60 2.05 0.02 0.21 0.04 12 0.10 I 3011 Predeveloped hydrograph.xls I 12/20/2018 I I Rational Method Hydrograph Calculations for 4205 Skyline Road, Carlsbad, CA (Pre-developed condition) 42 210 0.59 2.07 0.02 0.21 0.04 12 0.10 I 43 215 0.58 2.09 0.02 0.21 0.04 12 0.12 44 220 0.57 2.10 0.02 0.20 0.04 12 0.13 45 225 0.57 2.12 0.02 0.20 0.04 12 0.15 ' 46 230 0.56 2.14 0.02 0.20 0.04 12 0.17 47 235 0.55 2.15 0.02 0.19 0.04 11 0.26 48 240 0.54 2.17 0.02 0.19 0.04 11 0.36 49 245 0.54 2.19 0.02 0.19 0.04 11 1.30 I 50 250 0.53 2.20 0.02 0.19 0.04 11 0.21 51 255 0.52 2.22 0.02 0.18 0.04 11 0.14 52 260 0.52 2.23 0.02 0.18 0.04 11 0.11 53 265 0.51 2.25 0.01 0.18 0.04 11 0.09 I 54 270 0.50 2.26 0.01 0.18 0.03 10 0.08 55 275 0.50 2.28 0.01 0.18 0.03 10 0.07 I 56 57 280 285 0.49 0.49 2.29 2.31 0.01 0.01 0.17 0.17 0.03 0.03 10 10 0.06 0.06 58 290 0.48 2.32 0.01 0.17 0.03 10 0.05 59 295 0.47 2.33 0.01 0.17 0.03 10 0.05 60 300 0.47 2.35 0.01 0.17 0.03 10 0.05 I 61 305 0.46 2.36 0.01 0.16 0.03 10 0.05 62 310 0.46 2.38 0.01 0.16 0.03 10 0.04 63 315 0.46 2.39 0.01 0.16 0.03 9 0.04 I 64 320 0.45 2.40 0.01 0.16 0.03 9 0.04 65 325 0.45 2.42 0.01 0.16 0.03 9 0.04 66 330 0.44 2.43 0.01 0.16 0.03 9 0.04 I 67 335 0.44 2.44 0.01 0.15 0.03 9 0.03 68 340 0.43 2.45 0.01 0.15 0.03 9 0.03 69 345 0.43 2.47 0.01 0.15 0.03 9 0.03 70 350 0.43 2.48 0.01 0.15 0.03 9 0.03 I 71 355 0.42 2.49 0.01 0.15 0.03 9 0.03 72 360 0.42 2.51 0.00 0.00 0.00 0 0.03 1 SUM= 1776 0.04 cubic feet acre-feet I PREDEVELOPEDVOLUME= 1776 POSTDEVELOPED VOLUME = 1862 CHANGE IN VOLUME= 86 I 3011 Predeveloped hydrograph.xls 12/20/2018 I I Rational Method Hydrograph Calculations for 4205 Skyline Road, Carlsbad, CA (Pre-developed condition) I RM-HYDROGRAPH Project 1.40 1.20 1.00 0.80 CY 0.60 0.40 - 0.20 OW is 0.00 0 50 100 150 200 250 300 350 400 Time (mm) 3011 Predeveloped hydrograph.xls 12/20/2018 I I Rational Method Hydrograph Calculations for 4205 Skyline Road, Carlsbad, CA (Post-developed condition) I Q100 1.36 cfs Tc= 5 min C= 0.43 #= 72 P106= 2.5 in A= 0.48 acres (744*p6*DA 645) (IT/60) (VI-VO) (A V/A 7) (Q=ciA) (Re-ordered) D I VOL AVOL I(INCR) Q VOL ORDINATE # (MIN) (IN/HR) (IN) (IN) (IN/HR) (CFS) (CF) (CFS) 0 0 0.00 0.00 0.55 6.59 1.36 408 1 5 6.59 0.55 0.15 1.84 0.38 114 0.03 2 10 4.21 0.70 0.11 1.30 0.27 81 0.03 3 15 3.24 0.81 0.09 1.05 0.22 65 0.03 4 20 2.69 0.90 0.07 0.89 0.18 55 0.03 5 25 2.33 0.97 0.06 0.78 0.16 48 0.03 6 30 2.07 1.04 0.06 0.70 0.14 43 0.03 7 35 1.88 1.10 0.05 0.64 0.13 40 0.03 8 40 1.72 1.15 0.05 0.59 0.12 36 0.03 9 45 1.60 1.20 0.05 0.55 0.11 34 0.03 10 50 1.49 1.24 0.04 0.51 0.11 32 0.03 11 55 1.40 1.29 0.04 0.48 0.10 30 0.04 12 60 1.33 1.33 0.04 0.46 0.09 28 0.04 13 65 1.26 1.36 0.04 0.44 0.09 27 0.04 14 70 1.20 1.40 0.03 0.42 0.09 26 0.04 15 75 1.15 1.44 0.03 0.40 0.08 25 0.04 16 80 1.10 1.47 0.03 0.38 0.08 24 0.04 17 85 1.06 1.50 0.03 0.37 0.08 23 0.04 18 90 1.02 1.53 0.03 0.36 0.07 22 0.04 19 95 0.99 1.56 0.03 0.34 0.07 21 0.04 20 100 0.95 1.59 0.03 0.33 0.07 21 0.04 21 105 0.92 1.62 0.03 0.32 0.07 20 0.04 22 110 0.90 1.64 0.03 0.31 0.06 19 0.04 23 115 0.87 1.67 0.03 0.31 0.06 19 0.05 24 120 0.85 1.70 0.02 0.30 0.06 18 0.05 25 125 0.83 1.72 0.02 0.29 0.06 18 0.05 26 130 0.81 1.75 0.02 0.28 0.06 17 0.05 27 135 0.79 1.77 0.02 0.28 0.06 17 0.05 28 140 0.77 1.79 0.02 0.27 0.06 17 0.05 29 145 0.75 1.81 0.02 0.26 0.05 16 0.05 30 150 0.73 1.84 0.02 0.26 0.05 16 0.06 31 155 0.72 1.86 0.02 0.25 0.05 16 0.06 32 160 0.70 1.88 0.02 0.25 0.05 15 0.06 33 165 0.69 1.90 0.02 0.24 0.05 15 0.06 34 170 0.68 1.92 0.02 0.24 0.05 15 0.06 35 175 0.66 1.94 0.02 0.23 0.05 14 0.07 36 180 0.65 1.96 0.02 0.23 0.05 14 0.07 37 185 0.64 1.98 0.02 0.23 0.05 14 0.08 38 190 0.63 2.00 0.02 0.22 0.05 14 0.08 39 195 0.62 2.02 0.02 0.22 0.05 14 0.09 40 200 0.61 2.03 0.02 0.21 0.04 13 0.09 41 205 0.60 2.05 0.02 0.21 0.04 13 0.10 I 3011 Postdeveloped hydrograph.xls 1/7/2019 1 I I 1 I I 1 I I I I I Li I ' Rational Method Hydrograph Calculations for 4205 Skyline Road, Carlsbad, CA (Post-developed condition) I 42 210 0.59 2.07 0.02 0.21 0.04 13 0.11 43 215 0.58 2.09 0.02 0.21 0.04 13 0.12 I 44 220 0.57 2.10 0.02 0.20 0.04 13 0.13 45 225 0.57 2.12 0.02 0.20 0.04 12 0.16 46 230 0.56 2.14 0.02 0.20 0.04 12 0.18 I 47 235 0.55 2.15 0.02 0.19 0.04 12 0.27 48 240 0.54 2.17 0.02 0.19 0.04 12 0.38 49 245 0.54 2.19 0.02 0.19 0.04 12 1.36 I 50 250 0.53 2.20 0.02 0.19 0.04 12 0.22 51 255 0.52 2.22 0.02 0.18 0.04 11 0.14 52 260 0.52 2.23 0.02 0.18 0.04 11 0.11 53 265 0.51 2.25 0.01 0.18 0.04 11 0.09 I 54 270 0.50 2.26 0.01 0.18 0.04 11 0.08 55 275 0.50 2.28 0.01 0.18 0.04 11 0.07 56 280 0.49 2.29 0.01 0.17 0.04 11 0.07 I 57 285 0.49 2.31 0.01 0.17 0.04 11 0.06 58 290 0.48 2.32 0.01 0.17 0.03 10 0.06 59 295 0.47 2.33 0.01 0.17 0.03 10 0.05 ' 60 300 0.47 2.35 0.01 0.17 0.03 10 0.05 61 305 0.46 2.36 0.01 0.16 0.03 10 0.05 62 310 0.46 2.38 0.01 0.16 0.03 10 0.05 I 63 64 315 320 0.46 0.45 2.39 2.40 0.01 0.01 0.16 0.16 0.03 0.03 10 10 0.04 0.04 65 325 0.45 2.42 0.01 0.16 0.03 10 0.04 66 330 0.44 2.43 0.01 0.16 0.03 10 0.04 ' 67 335 0.44 2.44 0.01 0.15 0.03 10 0.04 68 340 0.43 2.45 0.01 0.15 0.03 9 0.04 69 345 0.43 2.47 0.01 0.15 0.03 9 0.03 70 350 0.43 2.48 0.01 0.15 0.03 9 0.03 I 71 355 0.42 2.49 0.01 0.15 0.03 9 0.03 72 360 0.42 2.51 0.00 0.00 0.00 0 0.03 SUM= 1862 cubic feet 1 0.04 acre-feet I PREDEVELOPEDVOLUME= 1776 POSTDEVELOPED VOLUME = 1862 CHANGE IN VOLUME= 86 1 I I I 3011 Postdeveloped hydrograph.xls 1/7/2019 I I I Rational Method Hydrograph Calculations for 4205 Skyline Road, Carlsbad, CA (Post-developed condition) RM-HYDROGRAPH Project 1.60 1.40 1.20 1.00 0.80 a 0.60 0.40 0.20 ..S...,.IS,SSflISISSSSSSS$' 0.00 .. 40.. I 0 50 100 150 200 250 300 350 0 Time (mm) I I I Li I 3011 Postdeveloped hydrograph.xls 1/7/2019 1 Li I I I I 1 I I I [1 Li Pritchard Residence 5.0 APPENDIX I I I I I El I I I I 1 I June 2017 10 C 471140 33 910' N 470177 470183 470183 Hydrologic Soil Group—San Diego County Area, California (Ciarmoli Residence -4205 Skyline Road) 470200 473210 4702W 4711137 4711140 41111,7' 41 33 9'8"N M al) [I . III' Valid at * 470140 470170 470140 4, ND 473232 473210 47 C Map Scale: 1:490 f printed on A landscape (lix 8.5") sheet. Meters N 0 5 10 20 20 - Feet ft 0 20 40 80 120 Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UThI Zone uN WGS84 ust Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey 4713240 473240 473240 12/17/2018 Page 1 of 4 Hydrologic Soil Group—San Diego County Area, California (Ciarmoli Residence - 4205 Skyline Road) MAP LEGEND MAP INFORMATION Area of Interest (AOl) Area of Interest (AOl) Soils Soil Rating Polygons ND BID C/D jjjj Not rated or not available Soil Rating Lines .. A , AID . B B/D -- C . CID ..- 0 , Not rated or not available Soil Rating Points o A El ND o B BID 13 C The soil surveys that comprise your AOl were mapped at 1.24000. o El DWarning: Soil Map may not be valid at this scale. Not rated or not available Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil Water Features line placement. The maps do not show the small areas of Streams and Canals contrasting soils that could have been shown at a more detailed scale. Transportation Rails Please rely on the bar scale on each map sheet for map Interstate Highways measurements. US Routes Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Major Roads Coordinate System: Web Mercator (EPSG:3857) Local Roads Maps from the Web Soil Survey are based on the Web Mercator Background projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Aerial Photography 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 13, Sep 12, 2018 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. USDA Natural Resources Web Soil Survey 12/1712018 Conservation Service National Cooperative Soil Survey Page 2 of 4 I 1 Hydrologic Soil Group—San Diego County Area, California Ciarmoli Residence - 4205 Skyline Road Hydrologic Soil Group Map unit symbol Map unit name Rating { Acres in AOl Percent of AOl MlC Marina loamy coarse sand, 2 to 9 percent B slopes 0.5 100.0% Totals for Area of Interest 0.5 100.0% 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 (AID, B/D, and CID). 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 (AID, 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. Rating Options Aggregation Method: Dominant Condition ri I I I I I I I I I L I 1 1 I USDA Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/17/2015 Page 3of4 I I I I I I I I I I I 1 I 1 I 1 I I I I Hydrologic Soil Group—San Diego County Area, California USDA Natural Resources Conservation Service Component Percent Cutoff: None Specified Tie-break Rule: Higher Web Soil Survey National Cooperative Soil Survey Ciarmoli Residence - 4205 Skyline Road 12/17/2018 Page 4 of 4