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HomeMy WebLinkAbout22SUB3 Drainage NarrativeREV 07252022 John U. Faulise, Jr., L.S. Demian A. Sorrentino, AICP, C.S.S. David C. McKay, P.E. Gerald J. Stefon, L.S. (1952-2021) Jacob S. Faulise, E.I.T. Boundaries LLC 179 Pachaug River Drive P.O. Box 184 Griswold, CT 06351 T 860.376.2006 | F 860.376.5899 www.boundariesllc.net June 2, 2022 (Revised July 18, 2022) RE: Drainage Narrative for Proposed Residential Subdivision East Lake Road and Fire Street Applicant: SUNMAR/RAF Builders, LLC. Boundaries Job I.D. No. 21-3036 Existing Conditions This proposal involves the subdivision of an existing 47.7-acre parcel located southeasterly of the intersection of East Lake Road and Fire Street into eight (8) lots intended for new single-family residential development. The subject property is primarily wooded area. The property generally slopes from southwest to north, from East Lake Road to Fire Street. One set of existing catch basins collects runoff from the right-of-way of East Lake Road and discharges through a swale onto proposed Lot 7. The remainder of the runoff from the subject parcel sheet flows through the wooded areas from southwest to north. According to the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Web Soil Survey for the State of Connecticut, the soil types underlying the conceptual development areas of the subdivision lots are: 73C Charlton-Chatfield complex, 15-45% slopes, very rocky Drainage Class = Moderately Well Drained Hydrologic Soil Group = B Proposed Conditions All proposed subdivision lots front East Lake Road and no public improvements (roadway or drainage) are proposed as a result of this subdivision. Runoff from East Lake Road is collected by a set of existing catch basins that drain to proposed Lot 7. A culvert will be installed on Lot 7 to divert the road drainage discharge around the development area. The existing culverts or catch basins that carry runoff onto the subject property will not be modified as a result of this project. The only runoff contributed to the East Lake Road right-of-way will be from the proposed paved driveway aprons. All other runoff from the driveways and proposed residences will flow into the vegetated areas of the development. The proposed development is intended to follow the design concepts listed Chapter 4.2 of the Connecticut Stormwater Quality Manual in order avoid negative impacts due to stormwater runoff: Page 2 • Designing the Development to Fit the Terrain: Proposed driveways generally follow the existing topography and maintain existing sheet flow runoff patterns. Houses are intended to be raised ranch style to work with the terrain of each individual lot. • Limiting Land Disturbance Activities: Clearing and grubbing is limited to the development area of each lot and along the right-of-way of East Lake Road to achieve adequate sight distances. The lots are larger than the minimum required lot areas in the zone providing for more undisturbed areas surrounding each residence. • Disconnecting Impervious Areas: The only impervious surfaces that will drain to East Lake Road and the associated cross culvert are the paved driveway aprons. The remainder of the driveway surfaces are either below the road elevation or will be provided with adequate cross-pitch to maintain existing sheet flow runoff patterns. Roof drainage is intended to discharge to vegetated surfaces surrounding the proposed residences disconnecting the roof runoff from the driveway surfaces. • Preserving and Utilizing Natural Drainage Systems: Stormwater runoff from the proposed development area is intended to follow the same sheet flow patterns as runoff from the existing wooded areas. • Providing Setbacks and Vegetated Buffers: No direct discharges from impervious surfaces to wetlands/watercourses are proposed as part of this development. No land disturbing activities are proposed within the 50-foot upland review area of the delineated wetlands. • Minimize the Creation of Steep Slopes: Minimal areas of 2H:1V slopes are proposed only to achieve required grading for the proposed subsurface sewage disposal systems. • Maintaining Pre-Development Vegetation: Clearing and grubbing of wooded areas has been minimized to the maximum extent practicable. Less than 12% of the parent parcel will be disturbed in order to develop the proposed subdivision. Stormwater Quantity and Quality The proposed development results in the creation of some new effectively impervious areas on the subject property including new paved and compacted gravel driveways, proposed roof areas, walkways and decks. Based on the conceptual development plans the new eight (8) lot subdivision will add 0.60 acres of effectively impervious area to the overall 47.7-acre property, resulting in impervious coverage of 1.3%, most of which drains to the undisturbed wooded areas downgradient of the proposed development area. Per Appendix 2 of the Connecticut Watershed Response Plan for Impervious Cover, areas with less than 10% of impervious coverage approximate “natural conditions” with respect to the amount and quality of stormwater runoff generated. Ultimately, runoff from the project area drains to Hunts Brook, located on the northerly side of Fire Street, which is over 550 feet from the closest land disturbing activity associated with the proposed development. Hunts Brook has a watershed of approximately 2.74 square miles or 1,754 acres upstream of the proposed development area (see Appendix C for the StreamStats report). The overall subject property accounts for 2.7 percent of the upstream watershed area and the proposed change in impervious coverage of the subject property is only 0.03 percent of the upstream watershed area. Given the extremely small percentage of the watershed affected by the development and the over 500-foot undisturbed buffer between the proposed development area and Hunts Brook this proposal will have no negative impact to stormwater quantity or quality in Hunts Brook or the surrounding downgradient areas. Page 3 There is an existing stormwater discharge from East Lake Road onto proposed Lot 7. A culvert is proposed to direct the stormwater runoff around the development area of Lot 7. The proposed culvert will be installed at the end of the existing discharge channel on Lot 7. The existing channel collects sediment from the road runoff, by leaving the channel intact, future maintenance needs of the culvert will be reduced since sediment will continue to collect in the channel before entering the culvert. The culvert is sized with greater capacity than the 100-year storm event in order to protect the development area of Lot 7, so any future upgradient improvements, development or modifications to the existing stormwater management system will not impact the operation of the culvert. The analysis of the 1.8- acre contributing watershed of the existing drain was completed assuming that the entire contributing area is impervious to ensure that the culvert is conservatively sized for all future conditions. The culvert has 0.15-feet of freeboard at the pipe inlet during the 100-year event and as a result backups and overflows of the system will be extremely unlikely and will not negatively impact the developed areas of the lot. The estimated 100-year flow rate of 14.1 cubic feet per second corresponds an average velocity of 4.6 feet per second. The inlet and outlet of the culvert are proposed to have pre-formed rip rap scour holes. The inlet scour hole is intended to aid in the removal of sediment from the stormwater before it enters the new culvert pipe. The outlet scour hole will protect the culvert outlet from erosion due to the stormwater discharge (see Appendix D for supporting calculations). The proposed improvements are shown on plans entitled “Subdivision Plan, Prepared for SUNMAR/RAF Builders, LLC, Property of Walter Wainwright, Jr., East Lake Road and Fire Street – Montville (Oakdale), Connecticut, June 2022,” prepared by Boundaries LLC. The proposed development will have no negative impact to stormwater quantity or quality in the surrounding downgradient areas. Enclosures: Appendix A – Location Map Appendix B – Conceptual Development Plans Appendix C – StreamStats Report Appendix D – Supporting Calculations Appendix A Location Map Location Map (Montville Quad) SUNMAR/RAF Builders, LLC East Lake Road & Fire Street Montville (Oakdale), Connecticut Appendix B Conceptual Development Plan and Drainage Areas         12345678RevisionsSHEET NO.1Appendix B "Conceptual Development Plans and Drainage Areas" Prepared for SUNMAR/RAF Builders, LLC East Lake Road & Fire Street - Montville (Oakdale), ConnecticutJune 2022JOB I.D. NO.\\192.168.2.3\PROJECTS\CIVIL 3D PROJECTS\2021\21-3036 FRANKLIN EAST LAKE RD\TECH\REVISED REPORT\APPENDIX A FIGURES.DWG 21-3036DATE:SCALE:1GRAPHIC SCALE1" = 100'©2022 BOUNDARIES LLCTHIS DRAWING IS THE PROPERTY OF BOUNDARIES LLC AND HAS BEEN SPECIFICALLYPREPARED FOR THE OWNER OF THIS PROJECT, AT THIS SITE, AND IS NOT TO BEDUPLICATED OR USED IN PART OR WHOLE FOR ANY OTHER PURPOSE, PROJECT, LOCATIONOR OWNER WITHOUT THE EXPRESSED WRITTEN CONSENT OF BOUNDARIES LLC.FIRE STREETDRAINAGE AREAEAST LAKE ROADDRAINAGE AREA(SEE APPENDIX DFOR WATERSHEDDELINEATION)WATERSHED DIVIDEFIRE STREETEAST LAKE ROAD Appendix C StreamStats Report StreamStats Report Collapse All   Basin Characteristics Parameter Code Parameter Description Value Unit DRNAREA Area that drains to a point on a stream 2.74 square miles I24H100Y Maximum 24-hour precipitation that occurs on average once in 100 years 7.79 inches I24H10Y Maximum 24-hour precipitation that occurs on average once in 10 years 5.07 inches I24H200Y Maximum 24-hour precipitation that occurs on average once in 200 years 8.88 inches Region ID:CT Workspace ID:CT20220705170524259000 Clicked Point (Latitude, Longitude):41.42797, -72.16691 Time:2022-07-05 13:03:26 -0400   Parameter Code Parameter Description Value Unit I24H25Y Maximum 24-hour precipitation that occurs on average once in 25 years 6.15 inches I24H2Y Maximum 24-hour precipitation that occurs on average once in 2 years - Equivalent to precipitation intensity index 3.17 inches I24H500Y Maximum 24-hour precipitation that occurs on average once in 500 years 10.33 inches I24H50Y Maximum 24-hour precipitation that occurs on average once in 50 years 6.97 inches I24H5Y Maximum 24-hour precipitation that occurs on average once in 5 years 4.25 inches LC11DEV Percentage of developed (urban) land from NLCD 2011 classes 21-24 3.11 percent LC11IMP Average percentage of impervious area determined from NLCD 2011 impervious dataset 0.28 percent SSURGOCCDD Percentage of area with hydrologic soil types C, D, or C/D from SSURGO 0.4733 percent   Peak-Flow Statistics Peak-Flow Statistics Parameters  [Statewide DA only SIR 2020 5054] Parameter Code Parameter Name Value Units Min Limit Max Limit DRNAREA Drainage Area 2.74 square miles 0.69 325 Peak-Flow Statistics Parameters  [Statewide Multiparameter SIR 2020 5054] Parameter Code Parameter Name Value Units Min Limit Max Limit DRNAREA Drainage Area 2.74 square miles 0.69 325 I24H2Y 24 Hour 2 Year Precipitation 3.17 inches 2.77 3.32 SSURGOCCDD Percent soil type C or D from SSURGO 0.4733 percent 0.118 0.945 I24H5Y 24 Hour 5 Year Precipitation 4.25 inches 4 4.7  Parameter Code Parameter Name Value Units Min Limit Max Limit I24H10Y 24 Hour 10 Year Precipitation 5.07 inches 4.86 5.79 I24H25Y 24 Hour 25 Year Precipitation 6.15 inches 5.99 7.22 I24H50Y 24 Hour 50 Year Precipitation 6.97 inches 6.81 8.3 I24H100Y 24 Hour 100 Year Precipitation 7.79 inches 7.62 9.38 I24H200Y 24 Hour 200 YearPrecipitation 8.88 inches 8.7 11.22 I24H500Y 24 Hour 500 Year Precipitation 10.33 inches 10.1 13.64 Peak-Flow Statistics Flow Report  [Statewide DA only SIR 2020 5054] PIl: Prediction Interval-Lower, PIu: Prediction Interval-Upper, ASEp: Average Standard Error of Prediction, SE: Standard Error (other -- see report) Statistic Value Unit ASEp Drainage Area Only 50-percent AEP flood 140 ft^3/s 35 Drainage Area Only 20-percent AEP flood 245 ft^3/s 35 Drainage Area Only 10-percent AEP flood 332 ft^3/s 36.3 Drainage Area Only 4-percent AEP flood 462 ft^3/s 37.8 Drainage Area Only 2-percent AEP flood 572 ft^3/s 39.8 Drainage Area Only 1-percent AEP flood 694 ft^3/s 42.4 Drainage Area Only 0.5-percent AEP flood 832 ft^3/s 44.4 Drainage Area Only 0.2-percent AEP flood 1040 ft^3/s 48 Peak-Flow Statistics Flow Report  [Statewide Multiparameter SIR 2020 5054] PIl: Prediction Interval-Lower, PIu: Prediction Interval-Upper, ASEp: Average Standard Error of Prediction, SE: Standard Error (other -- see report) Statistic Value Unit PIl PIu ASEp 50-percent AEP flood 147 ft^3/s 36.2 598 26.5 20-percent AEP flood 214 ft^3/s 47.7 961 26.3 10-percent AEP flood 266 ft^3/s 54.6 1300 28.4 4-percent AEP flood 351 ft^3/s 64.9 1900 31.5 2-percent AEP flood 424 ft^3/s 71.3 2520 34.3 1-percent AEP flood 506 ft^3/s 77.4 3310 37.1 0.5-percent AEP flood 593 ft^3/s 102 3460 40.6 Statistic Value Unit PIl PIu ASEp 0.2-percent AEP flood 738 ft^3/s 135 4040 45 Peak-Flow Statistics Flow Report  [Area-Averaged] PIl: Prediction Interval-Lower, PIu: Prediction Interval-Upper, ASEp: Average Standard Error of Prediction, SE: Standard Error (other -- see report) Statistic Value Unit ASEp Drainage Area Only 50-percent AEP flood 140 ft^3/s 35 Drainage Area Only 20-percent AEP flood 245 ft^3/s 35 Drainage Area Only 10-percent AEP flood 332 ft^3/s 36.3 Drainage Area Only 4-percent AEP flood 462 ft^3/s 37.8 Drainage Area Only 2-percent AEP flood 572 ft^3/s 39.8 Drainage Area Only 1-percent AEP flood 694 ft^3/s 42.4 Drainage Area Only 0.5-percent AEP flood 832 ft^3/s 44.4 Drainage Area Only 0.2-percent AEP flood 1040 ft^3/s 48 50-percent AEP flood 147 ft^3/s 36.2 598 26.5 20-percent AEP flood 214 ft^3/s 47.7 961 26.3 10-percent AEP flood 266 ft^3/s 54.6 1300 28.4 4-percent AEP flood 351 ft^3/s 64.9 1900 31.5 2-percent AEP flood 424 ft^3/s 71.3 2520 34.3 1-percent AEP flood 506 ft^3/s 77.4 3310 37.1 0.5-percent AEP flood 593 ft^3/s 102 3460 40.6 0.2-percent AEP flood 738 ft^3/s 135 4040 45 Peak-Flow Statistics Citations Ahearn, E.A., and Hodgkins, G.A.,2020, Estimating flood magnitude and frequency on streams and rivers in Connecticut, based on data through water year 2015: U.S. Geological Survey Scientific Investigations Report 2020–5054, 42 p. (https://doi.org/10.3133/sir20205054) USGS Data Disclaimer: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. USGS Software Disclaimer: This software has been approved for release by the U.S. Geological Survey (USGS). Although the software has been subjected to rigorous review, the USGS reserves the right to update the software as needed pursuant to further analysis and review. 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Application Version: 4.10.0 StreamStats Services Version: 1.2.22 NSS Services Version: 2.2.1 Appendix D Supporting Calculations NOAA Atlas 14, Volume 10, Version 3 Location name: Oakdale, Connecticut, USA* Latitude: 41.4341°, Longitude: -72.1826° Elevation: 193.02 ft*** source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Sandra Pavlovic, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Orlan Wilhite NOAA, National Weather Service, Silver Spring, Maryland PF_tabular | PF_graphical | Maps_&_aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5-min 0.338(0.264‑0.422)0.405(0.315‑0.506)0.514(0.399‑0.644)0.603(0.465‑0.760)0.727(0.543‑0.950)0.820(0.600‑1.09)0.918(0.653‑1.26)1.03(0.693‑1.44)1.19(0.772‑1.71)1.32(0.838‑1.94) 10-min 0.479(0.373‑0.598)0.573(0.446‑0.716)0.727(0.564‑0.911)0.854(0.659‑1.07)1.03(0.769‑1.35)1.16(0.850‑1.55)1.30(0.926‑1.79)1.46(0.981‑2.04)1.69(1.09‑2.43)1.88(1.19‑2.75) 15-min 0.564(0.439‑0.704)0.675(0.525‑0.843)0.856(0.664‑1.07)1.01(0.776‑1.27)1.21(0.905‑1.58)1.37(1.00‑1.82)1.53(1.09‑2.10)1.72(1.16‑2.40)1.99(1.29‑2.86)2.21(1.40‑3.23) 30-min 0.794(0.618‑0.990)0.949(0.738‑1.19)1.20(0.933‑1.51)1.41(1.09‑1.78)1.70(1.27‑2.23)1.92(1.41‑2.56)2.15(1.53‑2.96)2.41(1.62‑3.37)2.79(1.81‑4.01)3.10(1.96‑4.53) 60-min 1.02(0.797‑1.28)1.22(0.952‑1.53)1.55(1.20‑1.94)1.82(1.41‑2.29)2.20(1.64‑2.87)2.48(1.81‑3.30)2.77(1.97‑3.81)3.11(2.09‑4.34)3.59(2.33‑5.16)3.99(2.52‑5.83) 2-hr 1.35(1.06‑1.67)1.61(1.26‑1.99)2.03(1.59‑2.53)2.38(1.85‑2.98)2.87(2.16‑3.73)3.23(2.39‑4.28)3.62(2.60‑4.95)4.07(2.75‑5.63)4.73(3.08‑6.74)5.28(3.36‑7.65) 3-hr 1.57(1.23‑1.93)1.87(1.47‑2.31)2.36(1.85‑2.92)2.76(2.15‑3.44)3.32(2.51‑4.30)3.74(2.77‑4.93)4.18(3.02‑5.70)4.71(3.19‑6.48)5.48(3.58‑7.77)6.13(3.91‑8.83) 6-hr 1.99(1.58‑2.44)2.37(1.88‑2.91)2.98(2.36‑3.67)3.49(2.74‑4.31)4.19(3.19‑5.38)4.71(3.52‑6.16)5.27(3.82‑7.12)5.92(4.04‑8.08)6.89(4.52‑9.67)7.71(4.93‑11.0) 12-hr 2.47(1.98‑3.01)2.93(2.34‑3.57)3.68(2.93‑4.50)4.31(3.41‑5.29)5.17(3.96‑6.58)5.81(4.36‑7.53)6.49(4.73‑8.68)7.29(5.00‑9.85)8.45(5.56‑11.7)9.43(6.05‑13.3) 24-hr 2.89(2.33‑3.50)3.45(2.78‑4.18)4.37(3.51‑5.31)5.13(4.10‑6.25)6.18(4.77‑7.81)6.96(5.26‑8.95)7.79(5.71‑10.3)8.76(6.04‑11.7)10.2(6.74‑14.0)11.4(7.35‑15.9) 2-day 3.24(2.64‑3.89)3.91(3.18‑4.70)5.00(4.05‑6.03)5.91(4.76‑7.16)7.16(5.57‑9.00)8.09(6.17‑10.3)9.09(6.73‑12.0)10.3(7.12‑13.7)12.1(8.03‑16.5)13.6(8.83‑18.9) 3-day 3.51(2.87‑4.21)4.24(3.46‑5.08)5.43(4.41‑6.51)6.41(5.18‑7.73)7.77(6.07‑9.71)8.77(6.71‑11.2)9.85(7.32‑13.0)11.2(7.74‑14.7)13.1(8.74‑17.8)14.8(9.62‑20.4) 4-day 3.77(3.09‑4.50)4.54(3.72‑5.42)5.78(4.72‑6.92)6.82(5.53‑8.19)8.24(6.46‑10.3)9.30(7.13‑11.8)10.4(7.78‑13.7)11.8(8.21‑15.5)13.9(9.25‑18.7)15.7(10.2‑21.4) 7-day 4.50(3.71‑5.34)5.33(4.40‑6.33)6.70(5.50‑7.97)7.83(6.39‑9.36)9.39(7.40‑11.6)10.5(8.13‑13.3)11.8(8.81‑15.3)13.3(9.27‑17.3)15.5(10.3‑20.7)17.3(11.3‑23.5) 10-day 5.22(4.32‑6.17)6.09(5.04‑7.21)7.52(6.20‑8.92)8.71(7.14‑10.4)10.3(8.17‑12.7)11.6(8.93‑14.4)12.9(9.60‑16.5)14.4(10.1‑18.6)16.6(11.1‑22.0)18.4(12.0‑24.8) 20-day 7.42(6.20‑8.71)8.35(6.97‑9.82)9.88(8.22‑11.6)11.1(9.21‑13.2)12.9(10.2‑15.6)14.2(11.0‑17.5)15.6(11.6‑19.6)17.0(12.0‑21.8)19.0(12.8‑24.9)20.5(13.4‑27.4) 30-day 9.26(7.78‑10.8)10.2(8.58‑12.0)11.8(9.87‑13.9)13.1(10.9‑15.4)14.9(11.9‑18.0)16.3(12.7‑19.9)17.7(13.2‑22.0)19.1(13.5‑24.3)20.8(14.1‑27.2)22.1(14.5‑29.3) 45-day 11.5(9.74‑13.4)12.5(10.6‑14.6)14.2(11.9‑16.6)15.6(13.0‑18.3)17.5(14.0‑20.9)19.0(14.8‑22.9)20.4(15.2‑25.1)21.7(15.5‑27.5)23.3(15.8‑30.2)24.3(16.0‑32.0) 60-day 13.4(11.4‑15.6)14.5(12.3‑16.8)16.2(13.7‑18.9)17.7(14.8‑20.6)19.7(15.8‑23.4)21.2(16.6‑25.5)22.7(16.9‑27.7)24.0(17.1‑30.2)25.4(17.3‑32.8)26.3(17.4‑34.5) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates(for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upperbounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top PF graphical Back to Top Maps & aerials Small scale terrain Large scale terrain Large scale map Large scale aerial + – 3km 2mi + – 100km 60mi + – 100km 60mi Back to Top US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring, MD 20910 Questions?: HDSC.Questions@noaa.gov Disclaimer + – 100km 60mi © Connecticut Environmental Conditions Online 0.1 THIS MAP IS NOT TO BE USED FOR NAVIGATION Miles0.1 Notes Legend This map is intended for general planning, management, education, and research purposes only. Data shown on this map may not be complete or current. The data shown may have been compiled at different times and at different map scales, which may not match the scale at which the data is shown on this map. 0.040 1:2,257 East Lake Road Drainage Watershed Light Gray Canvas Base Hydrologic Soil Group—State of Connecticut Natural Resources Conservation Service Web Soil SurveyNational Cooperative Soil Survey 7/25/2022Page 1 of 4458960045897004589800458990045900004590100459020045903004590400458970045898004589900459000045901004590200459030045904004590500735800735900736000736100736200736300736400736500736600736700736800736900737000 735800 735900 736000 736100 736200 736300 736400 736500 736600 736700 736800 736900 737000 41° 25' 52'' N 72° 10' 44'' W41° 25' 52'' N72° 9' 46'' W41° 25' 23'' N 72° 10' 44'' W41° 25' 23'' N 72° 9' 46'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 300 600 1200 1800Feet 0 50 100 200 300Meters Map Scale: 1:6,210 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. 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 1:12,000. 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 ServiceWeb 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: State of ConnecticutSurvey Area Data: Version 21, Sep 7, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Data not available. 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—State of Connecticut Natural Resources Conservation Service Web Soil SurveyNational Cooperative Soil Survey 7/25/2022Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 3 Ridgebury, Leicester, and Whitman soils, 0 to 8 percent slopes, extremely stony D 1.4 1.3% 17 Timakwa and Natchaug soils, 0 to 2 percent slopes B/D 4.7 4.4% 38A Hinckley loamy sand, 0 to 3 percent slopes A 0.9 0.9% 38E Hinckley loamy sand, 15 to 45 percent slopes A 1.6 1.5% 50A Sutton fine sandy loam, 0 to 3 percent slopes B/D 5.2 4.9% 52C Sutton fine sandy loam, 2 to 15 percent slopes, extremely stony B/D 1.6 1.5% 60B Canton and Charlton fine sandy loams, 3 to 8 percent slopes B 4.4 4.1% 62C Canton and Charlton fine sandy loams, 3 to 15 percent slopes, extremely stony B 4.8 4.5% 62D Canton and Charlton fine sandy loams, 15 to 35 percent slopes, extremely stony B 41.9 39.6% 73C Charlton-Chatfield complex, 0 to 15 percent slopes, very rocky B 31.2 29.5% 73E Charlton-Chatfield complex, 15 to 45 percent slopes, very rocky B 1.0 0.9% 75C Hollis-Chatfield-Rock outcrop complex, 3 to 15 percent slopes D 1.3 1.3% 103 Rippowam fine sandy loam B/D 5.6 5.3% 306 Udorthents-Urban land complex B 0.2 0.2% Totals for Area of Interest 106.0 100.0% Hydrologic Soil Group—State of Connecticut Natural Resources Conservation Service Web Soil SurveyNational Cooperative Soil Survey 7/25/2022Page 3 of 4 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. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—State of Connecticut Natural Resources Conservation Service Web Soil SurveyNational Cooperative Soil Survey 7/25/2022Page 4 of 4 1S East Lake Road Drainage Catchment 2PCB Lot 7 Culvert Routing Diagram for Lot 7 Culvert SizingPrepared by Boundaries, LLC, Printed 7/18/2022HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Subcat Reach Pond Link Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 2HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Rainfall Events Listing Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 2-Year Type III 24-hr Default 24.00 1 3.45 2 2 10-Year Type III 24-hr Default 24.00 1 5.13 2 3 25-Year Type III 24-hr Default 24.00 1 6.18 2 4 50-Year Type III 24-hr Default 24.00 1 6.96 2 5 100-Year Type III 24-hr Default 24.00 1 7.79 2 Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 3HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 1.800 98 Paved parking, HSG B (1S) 1.800 98 TOTAL AREA Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 4HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 1.800 HSG B 1S 0.000 HSG C 0.000 HSG D 0.000 Other 1.800 TOTAL AREA Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 5HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.000 1.800 0.000 0.000 0.000 1.800 Paved parking 1S 0.000 1.800 0.000 0.000 0.000 1.800 TOTAL AREA Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 6HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line# Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Width (inches) Diam/Height (inches) Inside-Fill (inches) 1 2P 260.00 248.00 200.0 0.0600 0.013 0.0 24.0 0.0 Type III 24-hr 2-Year Rainfall=3.45"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 7HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Time span=0.00-30.00 hrs, dt=0.04 hrs, 751 pointsRunoff by SCS TR-20 method, UH=SCS, Weighted-CNReach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=1.800 ac 100.00% Impervious Runoff Depth=3.22"Subcatchment 1S: East Lake Road Tc=5.0 min CN=98 Runoff=6.16 cfs 0.482 af Peak Elev=261.08' Inflow=6.16 cfs 0.482 afPond 2P: Lot 7 Culvert 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' Outflow=6.16 cfs 0.482 af Total Runoff Area = 1.800 ac Runoff Volume = 0.482 af Average Runoff Depth = 3.22"0.00% Pervious = 0.000 ac 100.00% Impervious = 1.800 ac Type III 24-hr 2-Year Rainfall=3.45"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 8HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: East Lake Road Drainage Catchment Runoff = 6.16 cfs @ 12.07 hrs, Volume= 0.482 af, Depth= 3.22" Routed to Pond 2P : Lot 7 Culvert Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsType III 24-hr 2-Year Rainfall=3.45" Area (ac) CN Description 1.800 98 Paved parking, HSG B 1.800 100.00% Impervious Area Tc Length Slope Velocity Capacity Description(min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Min Tc Subcatchment 1S: East Lake Road Drainage Catchment Runoff Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)6 5 4 3 2 1 0 Type III 24-hr 2-Year Rainfall=3.45" Runoff Area=1.800 ac Runoff Volume=0.482 af Runoff Depth=3.22" Tc=5.0 min CN=98 6.16 cfs Type III 24-hr 2-Year Rainfall=3.45"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 9HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Pond 2P: Lot 7 Culvert Inflow Area = 1.800 ac,100.00% Impervious, Inflow Depth = 3.22" for 2-Year eventInflow = 6.16 cfs @ 12.07 hrs, Volume= 0.482 afOutflow = 6.16 cfs @ 12.07 hrs, Volume= 0.482 af, Atten= 0%, Lag= 0.0 minPrimary = 6.16 cfs @ 12.07 hrs, Volume= 0.482 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsPeak Elev= 261.08' @ 12.07 hrsFlood Elev= 262.00' Device Routing Invert Outlet Devices #1 Primary 260.00'24.0" Round Culvert L= 200.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 260.00' / 248.00' S= 0.0600 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 3.14 sf Primary OutFlow Max=6.06 cfs @ 12.07 hrs HW=261.07' (Free Discharge)1=Culvert (Inlet Controls 6.06 cfs @ 3.53 fps) Pond 2P: Lot 7 Culvert InflowPrimary Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)6 5 4 3 2 1 0 Inflow Area=1.800 ac Peak Elev=261.08' 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' 6.16 cfs6.16 cfs Type III 24-hr 10-Year Rainfall=5.13"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 10HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Time span=0.00-30.00 hrs, dt=0.04 hrs, 751 pointsRunoff by SCS TR-20 method, UH=SCS, Weighted-CNReach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=1.800 ac 100.00% Impervious Runoff Depth=4.89"Subcatchment 1S: East Lake Road Tc=5.0 min CN=98 Runoff=9.22 cfs 0.734 af Peak Elev=261.38' Inflow=9.22 cfs 0.734 afPond 2P: Lot 7 Culvert 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' Outflow=9.22 cfs 0.734 af Total Runoff Area = 1.800 ac Runoff Volume = 0.734 af Average Runoff Depth = 4.89"0.00% Pervious = 0.000 ac 100.00% Impervious = 1.800 ac Type III 24-hr 10-Year Rainfall=5.13"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 11HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: East Lake Road Drainage Catchment Runoff = 9.22 cfs @ 12.07 hrs, Volume= 0.734 af, Depth= 4.89" Routed to Pond 2P : Lot 7 Culvert Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsType III 24-hr 10-Year Rainfall=5.13" Area (ac) CN Description 1.800 98 Paved parking, HSG B 1.800 100.00% Impervious Area Tc Length Slope Velocity Capacity Description(min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Min Tc Subcatchment 1S: East Lake Road Drainage Catchment Runoff Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 10-Year Rainfall=5.13" Runoff Area=1.800 ac Runoff Volume=0.734 af Runoff Depth=4.89" Tc=5.0 min CN=98 9.22 cfs Type III 24-hr 10-Year Rainfall=5.13"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 12HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Pond 2P: Lot 7 Culvert Inflow Area = 1.800 ac,100.00% Impervious, Inflow Depth = 4.89" for 10-Year eventInflow = 9.22 cfs @ 12.07 hrs, Volume= 0.734 afOutflow = 9.22 cfs @ 12.07 hrs, Volume= 0.734 af, Atten= 0%, Lag= 0.0 minPrimary = 9.22 cfs @ 12.07 hrs, Volume= 0.734 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsPeak Elev= 261.38' @ 12.07 hrsFlood Elev= 262.00' Device Routing Invert Outlet Devices #1 Primary 260.00'24.0" Round Culvert L= 200.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 260.00' / 248.00' S= 0.0600 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 3.14 sf Primary OutFlow Max=9.06 cfs @ 12.07 hrs HW=261.36' (Free Discharge)1=Culvert (Inlet Controls 9.06 cfs @ 3.97 fps) Pond 2P: Lot 7 Culvert InflowPrimary Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.800 ac Peak Elev=261.38' 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' 9.22 cfs9.22 cfs Type III 24-hr 25-Year Rainfall=6.18"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 13HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Time span=0.00-30.00 hrs, dt=0.04 hrs, 751 pointsRunoff by SCS TR-20 method, UH=SCS, Weighted-CNReach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=1.800 ac 100.00% Impervious Runoff Depth=5.94"Subcatchment 1S: East Lake Road Tc=5.0 min CN=98 Runoff=11.13 cfs 0.891 af Peak Elev=261.56' Inflow=11.13 cfs 0.891 afPond 2P: Lot 7 Culvert 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' Outflow=11.13 cfs 0.891 af Total Runoff Area = 1.800 ac Runoff Volume = 0.891 af Average Runoff Depth = 5.94"0.00% Pervious = 0.000 ac 100.00% Impervious = 1.800 ac Type III 24-hr 25-Year Rainfall=6.18"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 14HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: East Lake Road Drainage Catchment Runoff = 11.13 cfs @ 12.07 hrs, Volume= 0.891 af, Depth= 5.94" Routed to Pond 2P : Lot 7 Culvert Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsType III 24-hr 25-Year Rainfall=6.18" Area (ac) CN Description 1.800 98 Paved parking, HSG B 1.800 100.00% Impervious Area Tc Length Slope Velocity Capacity Description(min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Min Tc Subcatchment 1S: East Lake Road Drainage Catchment Runoff Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 25-Year Rainfall=6.18" Runoff Area=1.800 ac Runoff Volume=0.891 af Runoff Depth=5.94" Tc=5.0 min CN=98 11.13 cfs Type III 24-hr 25-Year Rainfall=6.18"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 15HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Pond 2P: Lot 7 Culvert Inflow Area = 1.800 ac,100.00% Impervious, Inflow Depth = 5.94" for 25-Year eventInflow = 11.13 cfs @ 12.07 hrs, Volume= 0.891 afOutflow = 11.13 cfs @ 12.07 hrs, Volume= 0.891 af, Atten= 0%, Lag= 0.0 minPrimary = 11.13 cfs @ 12.07 hrs, Volume= 0.891 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsPeak Elev= 261.56' @ 12.07 hrsFlood Elev= 262.00' Device Routing Invert Outlet Devices #1 Primary 260.00'24.0" Round Culvert L= 200.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 260.00' / 248.00' S= 0.0600 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 3.14 sf Primary OutFlow Max=10.94 cfs @ 12.07 hrs HW=261.54' (Free Discharge)1=Culvert (Inlet Controls 10.94 cfs @ 4.22 fps) Pond 2P: Lot 7 Culvert InflowPrimary Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.800 ac Peak Elev=261.56' 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' 11.13 cfs11.13 cfs Type III 24-hr 50-Year Rainfall=6.96"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 16HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Time span=0.00-30.00 hrs, dt=0.04 hrs, 751 pointsRunoff by SCS TR-20 method, UH=SCS, Weighted-CNReach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=1.800 ac 100.00% Impervious Runoff Depth=6.72"Subcatchment 1S: East Lake Road Tc=5.0 min CN=98 Runoff=12.54 cfs 1.008 af Peak Elev=261.69' Inflow=12.54 cfs 1.008 afPond 2P: Lot 7 Culvert 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' Outflow=12.54 cfs 1.008 af Total Runoff Area = 1.800 ac Runoff Volume = 1.008 af Average Runoff Depth = 6.72"0.00% Pervious = 0.000 ac 100.00% Impervious = 1.800 ac Type III 24-hr 50-Year Rainfall=6.96"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 17HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: East Lake Road Drainage Catchment Runoff = 12.54 cfs @ 12.07 hrs, Volume= 1.008 af, Depth= 6.72" Routed to Pond 2P : Lot 7 Culvert Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsType III 24-hr 50-Year Rainfall=6.96" Area (ac) CN Description 1.800 98 Paved parking, HSG B 1.800 100.00% Impervious Area Tc Length Slope Velocity Capacity Description(min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Min Tc Subcatchment 1S: East Lake Road Drainage Catchment Runoff Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 50-Year Rainfall=6.96" Runoff Area=1.800 ac Runoff Volume=1.008 af Runoff Depth=6.72" Tc=5.0 min CN=98 12.54 cfs Type III 24-hr 50-Year Rainfall=6.96"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 18HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Pond 2P: Lot 7 Culvert Inflow Area = 1.800 ac,100.00% Impervious, Inflow Depth = 6.72" for 50-Year eventInflow = 12.54 cfs @ 12.07 hrs, Volume= 1.008 afOutflow = 12.54 cfs @ 12.07 hrs, Volume= 1.008 af, Atten= 0%, Lag= 0.0 minPrimary = 12.54 cfs @ 12.07 hrs, Volume= 1.008 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsPeak Elev= 261.69' @ 12.07 hrsFlood Elev= 262.00' Device Routing Invert Outlet Devices #1 Primary 260.00'24.0" Round Culvert L= 200.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 260.00' / 248.00' S= 0.0600 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 3.14 sf Primary OutFlow Max=12.33 cfs @ 12.07 hrs HW=261.67' (Free Discharge)1=Culvert (Inlet Controls 12.33 cfs @ 4.40 fps) Pond 2P: Lot 7 Culvert InflowPrimary Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.800 ac Peak Elev=261.69' 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' 12.54 cfs12.54 cfs Type III 24-hr 100-Year Rainfall=7.79"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 19HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Time span=0.00-30.00 hrs, dt=0.04 hrs, 751 pointsRunoff by SCS TR-20 method, UH=SCS, Weighted-CNReach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=1.800 ac 100.00% Impervious Runoff Depth=7.55"Subcatchment 1S: East Lake Road Tc=5.0 min CN=98 Runoff=14.05 cfs 1.133 af Peak Elev=261.85' Inflow=14.05 cfs 1.133 afPond 2P: Lot 7 Culvert 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' Outflow=14.05 cfs 1.133 af Total Runoff Area = 1.800 ac Runoff Volume = 1.133 af Average Runoff Depth = 7.55"0.00% Pervious = 0.000 ac 100.00% Impervious = 1.800 ac Type III 24-hr 100-Year Rainfall=7.79"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 20HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: East Lake Road Drainage Catchment Runoff = 14.05 cfs @ 12.07 hrs, Volume= 1.133 af, Depth= 7.55" Routed to Pond 2P : Lot 7 Culvert Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsType III 24-hr 100-Year Rainfall=7.79" Area (ac) CN Description 1.800 98 Paved parking, HSG B 1.800 100.00% Impervious Area Tc Length Slope Velocity Capacity Description(min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Min Tc Subcatchment 1S: East Lake Road Drainage Catchment Runoff Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 100-Year Rainfall=7.79" Runoff Area=1.800 ac Runoff Volume=1.133 af Runoff Depth=7.55" Tc=5.0 min CN=98 14.05 cfs Type III 24-hr 100-Year Rainfall=7.79"Lot 7 Culvert Sizing Printed 7/18/2022Prepared by Boundaries, LLC Page 21HydroCAD® 10.20-2d s/n 04031 © 2021 HydroCAD Software Solutions LLC Summary for Pond 2P: Lot 7 Culvert Inflow Area = 1.800 ac,100.00% Impervious, Inflow Depth = 7.55" for 100-Year eventInflow = 14.05 cfs @ 12.07 hrs, Volume= 1.133 afOutflow = 14.05 cfs @ 12.07 hrs, Volume= 1.133 af, Atten= 0%, Lag= 0.0 minPrimary = 14.05 cfs @ 12.07 hrs, Volume= 1.133 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.04 hrsPeak Elev= 261.85' @ 12.07 hrsFlood Elev= 262.00' Device Routing Invert Outlet Devices #1 Primary 260.00'24.0" Round Culvert L= 200.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 260.00' / 248.00' S= 0.0600 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 3.14 sf Primary OutFlow Max=13.81 cfs @ 12.07 hrs HW=261.82' (Free Discharge)1=Culvert (Inlet Controls 13.81 cfs @ 4.60 fps) Pond 2P: Lot 7 Culvert InflowPrimary Hydrograph Time (hours)3029282726252423222120191817161514131211109876543210Flow (cfs)15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.800 ac Peak Elev=261.85' 24.0" Round Culvert n=0.013 L=200.0' S=0.0600 '/' 14.05 cfs14.05 cfs