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2023.08.31 - Stamped Stormwater Management Report
HANCOCK ASSOCIATES Stormwater Management Report #492 SUTTONTT North Andover, MA Prepared For: Home Grown Lacrosse, LLC 400 Osgood Street North Andover, MA 01845 .6 W Prepared By: f " Brian Geaudreau, PE >. Morgan Seale Project: 27016 Date: August 30, 2023 Revised: 34 Chelmsford Street, 2nd Flour ! Chelmsford, MA 01824 V. 978-244-0110 F:978-244-1133 I IlancockAssociates.com RII_" DR,iC C) N, I E L 10 SF� al'1 :�, I_)A ,JVI R:7,, I`v/YARL,B GI I, II—uVBJR,°r'!'C.I' J, NaE:;l. i I, �/I i.[M1, V Jh i Table of Contents BACKGROUND INFORMATION A.) Project Description B.) Existing Conditions C.) Proposed Conditions-Stormwater Management Narrative DOCUMENTING COMPLIANCE A.) MassDEP Stormwater Standards 1. No Untreated Discharges or Erosion to Wetlands 2. Peak Rate Attenuation i. Runoff Summary Table 3. Stormwater Recharge i. Soil Evaluation ii. Required Recharge Volume iii. Sizing • 'Static"Method • `Simple Dynamic"Method • "Dynamic Field"Method iv. 72-hour Drawdown Analysis v. Capture Area Adjustment vi. Mounding Analysis 4. Water Quality i. TSS Removal Train • Weighted Average Calculation ii. Water Quality Volume Calculation 5. Land Uses With Higher Potential Pollutant Loads (LUHPPLs) 6. Critical Areas 7. Redevelopments and Other Projects Subject to the Standards only to the Maximum Extent Practicable 8. Construction Period Pollution Prevention and Erosion &Sedimentation Controls i. Erosion and Sediment Control Plan 9. Operation and Maintenance Plan i. Owner Certification Statement ii. BMP Inspection Logs 10. Prohibition of Illicit Discharges i. Illicit Discharge Statement SOILS INFORMATION A.) USDA NRCS Web Soil Survey Information ATTACHMENTS • Pre-development Subcatchment Plan • Post-development Subcatchment Plan • HydroCAD Worksheets • USGS Topographic Map • NHESP Endangered Species and Critical Habitat Map • FEMA Firmette Map Background Information A. Project Description This project intends to construct a 39,100±SF athletic facility with office space, accompanying parking lot and utilities on a leased lot granted by the Lawrence Municipal Airport. Said lease area is proposed to be 2.5±Acres. The proposed building will be provided with gas and water service from the existing underground services along the airport entrance road (Terminal Road). Sewer service will be provided by connecting to an existing sewer manhole approximately 900 feet north of the intersection of Terminal Road and Sutton Street. In order to mitigate any increase in stormwater runoff from the proposed development, stormwater management practices have been designed to mirror existing drainage patterns and provide full compliance with MassDEP Stormwater Management Standards. Best Management Practices (BMPs) include a porous pavement system sized to meet all performance requirements. B. Existing Site Conditions The subject lot is located along the eastern side of Terminal Road. Existing conditions include maintained grass fields, disturbed earth from removal of soil stockpiling, and a small portion of woods.The site is located in the Industrial 2 district with a portion being within the Watershed Protection District. Stormwater runoff from the site is divided between two discharge areas,the southern end of Terminal Road/Sutton Street, and the northern end of Terminal Road. An on the ground survey was performed by Hancock Associates through the Summer of 2023.The site is partially located within the Watershed Protection District: General Zone and Watershed Protection District: Non- Discharge Zone. Onsite soils are mapped as Hydrologic Group C by USDA NRCS Web Soil Survey. C. Proposed Conditions—Stormwater Management and Methodology The Stormwater Management design methodology implemented for this project is intended to treat and exfiltrate runoff via a porous pavement system.This hydrologic analysis methodology will approximate pre- development peak flow rates at design points:The Northern portion of Terminal Road and the Sutton Street/Old Clark Road Drainage System. Terminal Road-North(1S/9S) In existing site conditions runoff from the northern portion of the lot drains to the north into the existing drainage system of Terminal Road. In the post-development condition the contributory area will be decreased, thus allowing for less runoff as the majority of the stormwater will be directed to the porous pavement. Sutton Street/Old Clark Road (3S/11R) In existing site conditions runoff from the majority of the lot drains overland to the south east into the Old Clark Road and Sutton Street drainage systems. Post-development conditions will maintain the overall drainage with additional runoff from impervious surfaces being treated and attenuated by the proposed porous pavement parking lot. Documenting Compliance A. MassDEP Stormwater Management Standards The following sections provide a discussion of how the requirements of the Stormwater Management Standards are addressed by the proposed new development. Standard 1: No Untreated Discharges or Erosion to Wetlands No new stormwater conveyances(e.g. outfalls) may discharge untreated stormwater directly to or cause erosion in wetlands or waters of the Commonwealth. No new untreated conveyances or direct discharge to wetlands are proposed; all points of discharge mirror existing discharge patterns. See computations completed in Standards 4& 6 that demonstrate proper treatment of suspended solids and required water quality volume. Standard 2: Peak Rate Attenuation Stormwater Management Systems must be designed so that post-development peak discharge rates do not exceed pre-development discharge rates. Runoff Summary Table: Rainfall Frequency 2-year 10-year 25-year 100-year 24-hour Rainfall Intensity 3.15 in 4.99 in 6.14 in 7.91 in Pre-Development Overland to Terminal Rd. North 0.71 cfs 1.81 cfs 2.57 cfs 3.80 cfs 16,574 cf (1S) Post-Development Overland to Terminal Rd. North 0.68 cfs 1.68 cfs 2.36 cfs 3.46 cfs 10,251 cf (9S) Delta -0.03 cfs -0.13 cfs -0.21 cfs -0.34 cfs -6323 cf Percentage Difference(%) -4.0% -7.2% -8.2% -8.9% -38.2% Pre-Development Overland to Old Clark Rd. & 1.30 cfs 3.32 cfs 4.72 cfs 6.98 cfs 32,793cf Sutton St. (2S) Post-Development Overland to Old Clark Rd. & 1.16 cfs 2.93 cfs 4.16 cfs 6.15 cfs 22,978 cf Sutton St. (16R) Delta -0.14 cfs -0.39 cfs -0.56 cfs -0.83 cfs -9,815 cf Percentage Difference(%) -10.8% -11.7% -11.9% -11.9% -29.9% To model time of concentration values (Tc)for the proposed porous pavement,the ratio of 790minutes/41inches was used as referenced in the University of New Hampshire Stormwater Center's "UNHSC Design Specifications for Porous Asphalt Pavement and Infiltration Beds".The cross section of the proposed porous pavement is equal to 31 inches, which equates to a Tc of 597 minutes. As detailed in the Stormwater Methodology and Introduction and summarized in the preceding table,there will be no increase in peak runoff rate for the 2, 10, or 100-year frequency events as compared to existing conditions. HydroCAD worksheets are attached herewith. Standard 3: Stormwater Recharge Loss of annual recharge to groundwater shall be eliminated or minimized through the use of infiltration measures including environmentally sensitive site design, low impact development techniques,stormwater best management practices,and good operation and maintenance. At a minimum,the annual recharge from the post-development site should approximate the annual recharge from the pre-development conditions based on soil type. This standard is met when the stormwater management system is designed to infiltrate the required recharge volume as determined in accordance with the Massachusetts Stormwater Handbook. Required Recharge Volume The Required Recharge Volume equals a depth of runoff corresponding to the soil type times the impervious areas covering that soil type at the post-development site. Rv =F x impervious area Equation (1) Rv =Required Recharge Volume, expressed in Ft3, cubic yards, or acre-feet F = Target Depth Factor Impervious Area =pavement and rooftop area on site Target Depth Factor(F) =0.25 inch (Class C Hydrologic Soils) Rv= (0.25 inch x 1 ft/ 12 IN) (58,340 SF) = 1,215 CF Total Recharge Required = 1,215 CF 1 inch retention volume (required to achieve 90%TSS removal-see Standard 4): (1 inch x 1 ft/12 IN) (58,340 SF) =4,861 CF Required retention Volume=4,861 CF Recharge Facility Volume Porous Pavement Reservoir 4,933 CF( >4,861 CF) Drawdown within 72 Hours _ Rv Tl m edr^awdown (K)(Bottom Area) Rv=Storage Volume K =Saturated Hydraulic Conductivity For "Static"and"Simple Dynamic"Methods, use Rawls Rate (see Table 2.3.3). For "Dynamic Field"Method, use 50%of the in-situ saturated hydraulic conductivity. Bottom Area=Bottom Area of Recharge Structure Proposed Porous Pavement Time=4,933 CF/ [(1.02 inches/hour) (1ft/ 12inches) (19,890 SF)] Time= 2.9 hours (<72 hours) Mounding Analysis Porous Pavement Length = 136' Width = 146.25' Application Rate: 4,933 cf/day/19890 sf =0.248 cf/day/sf Fillable Porosity(Specific Yield): Soil Desc: LS Yield Values: 0.23 Saturated Hydraulic Conductivity(Ksat ) = 3ft/day for fine sands The mounding analysis shown on the following page demonstrates the impact of the porous pavement infiltration on the estimated groundwater table. During a 100-year storm event the amount of water infiltrated by the reservoir course of the pavement causes the groundwater table to rise 1.07 feet above its normal level thus having no effect on the practice. Groundwater Mounding Analysis (Hantush's Method using Glover's Solution) 1.2 1.0 0.8 L 0.6 LM 0.4 0.2 0.0 0 1 2 3 4 5 Time(day) UIIIIIIIU1QlUlUlUlD1➢1lYIYIN/Y/C/GC/4%////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////� gM91➢IYIYIN/Y/C/GC/4%/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////OAf MODEL RESULTS COMPANY: Hancock Associates Mound PROJECT: 27016-HGR Lacrosse Time Height (day) (ft) ANALYST: Morgan Seale 0 0 DATE: 8/30/2023 TIME: 2:03:07 PM 0 0.01 0 0.05 INPUT PARAMETERS 0.1 0.1 0.2 0.17 Application rate: 0.2484 c.ft/day/sq. ft 0.2 0.24 Duration of application: 1 day 0.3 0.32 Total simulation time: 5 day 0.4 0.43 Fillable porosity: 0.23 0.5 0.56 Hydraulic conductivity: 3 ft/day 0.7 0.75 Initial saturated thickness: 30 ft 1 1.07 Length of application area: 136 ft 1.1 1.07 Width of application area: 146 ft 1.2 1.07 No constant head boundary used 1.4 1.06 Groundwater mounding @ 1.6 1.04 X coordinate: 0 ft 1.9 1.01 Y coordinate: 0 ft 2.2 0.96 Total volume applied: 4932.23 cft 2.6 0.91 3.1 0.84 3.8 0.75 5 0.63 Standard 4: Water Quality Stormwater management systems shall be designed to remove 80%of the average annual post-construction load of Total Suspended Solids(TSS). This standard is met when: (a) Suitable practices for source control and pollution prevention are identified in a long-term pollution prevention plan, and thereafter are implemented and maintained; (b)Structural stormwater best management practices are sized to capture the required water quality volume determined in accordance with the Massachusetts Stormwater Handbook; and (c) Pretreatment is provided in accordance with the Massachusetts Stormwater Handbook. The required water quality volume equals 1.0 inch of runoff times the total impervious area of the post- development project site for a discharge • from a land use with a higher potential pollutant load; • within an area with a rapid infiltration rate (greater than 2.4 inches per hour); • within a Zone II or Interim Wellhead Protection Area; • near or to the following critical areas: o Outstanding Resource Waters, o Special Resource Waters, o bathing beaches, o shellfish growing areas, o cold-water fisheries. i.TSS Removal for Porous Pavement: TSS Removal Efficiency=90% if storage bed sized to retain 1"water quality volume drained within 72 hours. -MA MS4 General Permit section:2.3.6a.ii.3.0.2 TSS Removal Percentage Computations: BMP TSS REMOVAL RATE STARTING TSS AMOUNT REMAINING LOAD LOAD REMOVED Porous Pavement 90% 100% 90% 10% Total Phosphorus(TP) removal: TP Removal Efficiency=62%with 12"filter course -(Table 3-22 of Appendix F,Attachment 3, MA MS4 General Permit) Standard 5: Land Uses with Higher Potential Pollutant Loads For land uses with higher potential pollutant loads,source control and pollution prevention shall be implemented in accordance with the Massachusetts Stormwater Handbook to eliminate or reduce the discharge of stormwater runoff from such land uses to the maximum extent practicable. If through source control and/or pollution prevention all land uses with higher potential pollutant loads cannot be completely protected from exposure to rain,snow,snow melt,and stormwater runoff,the proponent shall use the specific structural stormwater BMPs determined by the Department to be suitable for such uses as provided in the Massachusetts Stormwater Handbook. Stormwater discharges from land uses with higher potential pollutant loads shall also comply with the requirements of the Massachusetts Clean Waters Act, M.G.L.c. 21, A§A§26-53 and the regulations promulgated thereunder at 314 CMR 3.00, 314 CMR 4.00 and 314 CMR 5.00. The proposed development does not qualify as a Land Use with Higher Potential Loads (LUHPPLs). Standard 6: Critical Areas Stormwater discharges within the Zone II or Interim Wellhead Protection Area of a public water supply, and stormwater discharges near or to any other critical area, require the use of the specific source control and pollution prevention measures and the specific structural stormwater best management practices determined by the Department to be suitable for managing discharges to such areas, as provided in the Massachusetts Stormwater Handbook.A discharge is near a critical area if there is a strong likelihood of a significant impact occurring to said area,taking into account site-specific factors. Stormwater discharges to Outstanding Resource Waters and Special Resource Waters shall be removed and set back from the receiving water or wetland and receive the highest and best practical method of treatment. A"storm water discharge"as defined in 314 CMR 3.04(2)(a)1 or(b)to an Outstanding Resource Water or Special Resource Water shall comply with 314 CMR 3.00 and 314 CMR 4.00. Stormwater discharges to a Zone I or Zone A are prohibited unless essential to the operation of a public water supply. This project does not discharge to critical areas. The proposed development meets this standard. Standard 7: Redevelopments Subject to the Standards only to the Maximum Extent Practicable A redevelopment project is required to meet the following Stormwater Management Standards only to the maximum extent practicable: Standard 2,Standard 3,and the pretreatment and structural best management practice requirements of Standards 4, 5,and 6. Existing stormwater discharges shall comply with Standard 1 only to the maximum extent practicable. A redevelopment project shall also comply with all other requirements of the Stormwater Management Standards and improve existing conditions. The proposed project is not a redevelopment and shall comply with all other requirements of the Stormwater Management Standards to the maximum extent practicable. Standard 8: Construction Period Pollution Prevention and Erosion & Sedimentation Controls A plan to control construction-related impacts including erosion, sedimentation and other pollutant sources during construction and land disturbance activities(construction period erosion,sedimentation, and pollution prevention plan) shall be developed and implemented. EROSION AND SEDIMENTATION CONTROL PLAN Best management practices(BMP)for erosion and sedimentation control are staked silt fence, hydro seeding,and phased development. Many stormwater BMP technologies (e.g., infiltration technologies) are not designed to handle the high concentrations of sediments typically found in construction runoff and must be protected from construction-related sediment loadings. Construction BMP's must be maintained. In developing the proposed project certain measures will be implemented to minimize impacts erosion and sedimentation could have on surrounding areas. This section addresses items that involve proper construction techniques, close surveillance of workmanship, and immediate response to emergency situations.The developer must be prepared to provide whatever reasonable measures are necessary to protect the environment during construction and to stabilize all disturbed areas as soon as construction ends. Pre-Construction 1. Prior to clearing,excavation,construction,or any land disturbing activity requiring a permit,the applicant, the applicant's technical representative,the general contractor, pertinent subcontractors,and any person with authority to make changes to the project,shall meet with the Town's designated Agent and to review the permitted plans and proposed implementation. 2. The contractor shall have a stockpile of materials required to control erosion on-site to be used to supplement or repair erosion control devices. These materials shall include, but are not limited to straw wattles, catch basin filter bags and crushed stone. 3. The contractor is responsible for erosion control on site and shall utilize erosion control measures where needed, regardless of whether the measures are specified on the plan or in the decisions. Preliminary Site Work 1. Materials such as gravel to be removed should be stockpiled, separating the topsoil for future use on the site. Erosion control shall be utilized along the down slope side of the piles if the piles are to remain for more than three weeks. 2. If intense rainfall is anticipated, the installation of supplemental straw bale dikes, silt fences, or armored dikes shall be considered. Site Inspections During Construction 1. During construction,the permittee or his/her Agent shall conduct and document inspections of all control measures no less than weekly or as specified in the permit, and prior to and following anticipated storm events.The purpose of such inspections will be to determine the overall effectiveness of the Erosion and Sedimentation Control Plan, and the need for maintenance or additional control measures. Porous Pavement Installation 1. Porous pavement shall be installed only after construction proposed structures and grading has been completed in order to ensure proper underlying infiltration soil interfacing and protection of porous system from damage during construction. 2. Pavement shall be vacuum swept and cleared of all remaining construction debris and/or loose materials following construction and site stabilization. Landscaping/Seeding 1. Landscaping/Seeding shall occur as soon as possible to provide permanent stabilization of disturbed surfaces. 2. If the season or adverse weather conditions do not allow the establishment of vegetation, temporary mulching with straw, wood chips weighted with snow fence or branches, or other methods shall be provided. 3. A minimum of 4 inches of topsoil shall be placed and its surface smoothed to the specified grades. 4. The use of herbicides is strongly discouraged. 5. Hydro seeding is encouraged for steep slopes. Application rates on slopes greater than 3:1 shall have a minimum seeding rate of 5-Ibs/1000 SF. A latex or fiber tackifier shall be used on these slopes at a minimum rate of 50 lbs. of tackifier per 500 gallons of water used. Standard 9: Operation and Maintenance Plan A long-term operation and maintenance plan shall be developed and implemented to ensure that stormwater management systems function as designed. STORMWATER OPERATION AND MAINTENANCE PLAN Corporate Certification (Home Grown Lacrosse, LLC—Owner/Developer) I certify under penalty of law that the Owner/Developer and its associated entities established for purposes of ownership, operations and maintenance of the property located at South Street, Carlisle, MA 01741, is solely and legally responsible for implementing the Stormwater Operation and Maintenance Plan. The Owner/Developer has reviewed said plan and fully accepts all responsibilities inherent therein; including inspection, maintenance, repair, modification and/or replacement of the recharge systems as may be required to maintain intended recharge functions.The Owner/Developer shall file yearly maintenance reports including annual certification that the plan has been fully implemented as outline herein. Furthermore,the Owner/Developer understands various stormwater management systems have a certain life expectancy and that replacement of system components will be required.The Owner/Developer accepts all financial responsibilities associated with future replacements. Name: Title: Date: HGR Lacrosse 400 Osgood Street North Andover, MA 01845 (978) 208-2300 Bryan@hgrlacrosse.com Porous Pavement Frequent cleaning and maintenance are required for the pavement surface to prevent clogging as the surface acts as the pretreatment to the stone reservoir below.To keep the surface clean, frequent vacuum sweeping along with jet washing of asphalt and concrete pavement is required. No winter sanding shall be conducted on the porous surface. For proper maintenance: • Minimize salt use during winter months, • No winter sanding, • Keep landscaped areas nearby well maintained to prevent soil being transported onto the pavement, • Clean the surface at least monthly with vacuum sweeping machines, • Inspect surface after storm events to insure proper drainage, • Never reseal or repave with impermeable material, • Inspect annually for deterioration or spalling, • Monitor to ensure that the paving surface drains properly after storms—as needed • Clean surface using power washer to dislodge trapped particles and vacuum sweep area—as needed • Inspect surface annually for deterioration • Assess exfiltration capability at least once a year. When exfiltration capacity is found to decline, implement measures from the Operation and Maintenance plan to restore original exfiltration capacity. Inspection & Maintenance Report Attach additional pages as required to fully document conditions and maintenance performed. Date Inspector Condition Maintenance Performed* *Receipts must be attached to the report showing payment for maintenance performed. Grass Swale Inspect semi-annually the first year, and at least once a year thereafter. Inspect the grass for growth and the side slopes for signs of erosion and formation of rills and gullies. Plant an alternative grass species if the original grass cover is not successfully established. If grass growth is impaired by winter road salt or other deicer use, re- establish the grass in the spring.Trash/Debris Removal: Remove accumulated trash and debris prior to mowing. Sediment Removal: Check on a yearly basis and clean as needed. Use hand methods (i.e., a person with a shovel) when cleaning to minimize disturbance to vegetation and underlying soils. Annual Inspection & Maintenance Report Attach additional pages as required to fully document conditions and maintenance performed. Date Inspector Condition Maintenance Performed* *Receipts must be attached to report showing payment for maintenance performed Standard 10: Illicit Discharges to Drainage System All illicit discharges to the stormwater management system are prohibited. Measures to prevent illicit discharges are included in Standard 4 &8 of this report. It is the responsibility of the owner post construction to uphold this standard. A no illicit discharges statement has not been attached but will be submitted by the owner prior to discharge of stormwater to post construction BM Ps. Illicit Discharge Compliance Statement To the best of my knowledge no illicit discharges currently exist on the site and no future illicit discharge will be allowed, including wastewater discharges and discharges of stormwater contaminated by contact with process wastes, raw materials, toxic pollutants, hazardous substances, oil, or grease. Signed by Owner Date Soil Information USDA NRCS WEB SOIL SURVEY INFORMATION Soil Map—Essex County,Massachusetts, Northern Part 325900 326100 326300 326500 326700 326900 327100 42°43 25"N 42°43 25"N NO f n _ a a f i QQ �1 r � 1 0 l� v i 42°42'20"N 42°42'20"N 325700 325900 326100 3263M 32MM 326700 326900 327100 - h Map Scale:1:9,750 if printed on A portrait(8.5"x 11")sheet Meters N 0 100 200 400 600 A Feet 0 450 900 1800 2700 Map projection:Web Mercator Comer coordinates:WGS84 Edge tics:UTM Zone 19N WGS84 tJSl)A Natural Resources Web Soil Survey 6/27/2023 Conservation Service National Cooperative Soil Survey Page 1 of 3 Soil Map—Essex County,Massachusetts, Northern Part MAP LEGEND MAP INFORMATION Area of Interest(AOq Spoil Area The soil surveys that comprise your AOI were mapped at Area of Interest(AOI) 1:15,800. Stony Spot Soils Please rely on the bar scale on each map sheet for map Very Stony Spot Soil Map Unit Polygons measurements. Wet Spot Source of Map: Natural Resources Conservation Service Soil Map Unit Lines F Other Web Soil Survey URL: Soil Map Unit Points Coordinate System: Web Mercator(EPSG:3857) Special Line Features Special Point Features Maps from the Web Soil Survey are based on the Web Mercator o- Blowout water Features projection,which preserves direction and shape but distorts Streams and Canals distance and area.A projection that preserves area,such as the Borrow Pit Albers equal-area conic projection,should be used if more Clay Spot Transportation accurate calculations of distance or area are required. Rails Closed Depression This product is generated from the USDA-NRCS certified data as _ Interstate Highways of the version date(s)listed below. Gravel Pit US Routes Soil Survey Area: Essex County, Massachusetts, Northern Part Gravelly Spot Major Roads Survey Area Data: Version 18,Sep 9,2022 C. Landfill Local Roads Soil map units are labeled(as space allows)for map scales Lava Flow 1:50,000 or larger. L Background Marsh or swamp Aerial Photography Date(s)aerial images were photographed: May 22,2022—Jun 5,2022 M Mine or Quarry The orthophoto or other base map on which the soil lines were Miscellaneous Water compiled and digitized probably differs from the background imagery displayed on these maps.As a result,some minor Perennial water shifting of map unit boundaries may be evident. Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip 0o Sodic Spot USDA Natural Resources Web Soil Survey 6/27/2023 Conservation Service National Cooperative Soil Survey Page 2 of 3 Soil Map-Essex County, Massachusetts, Northern Part Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 1 Water 15.0 2.9% 6A Scarboro mucky fine sandy 7.5 1.5% loam,0 to 3 percent slopes 31A Walpole sandy loam,0 to 3 6.6 1.3% percent slopes 52A Freetown muck,0 to 1 percent 4.8 0.9% slopes 70A Ridgebury fine sandy loam,0 8.6 1.7% to 3 percent slopes 260A Sudbury fine sandy loam,0 to 4.3 0.8% 3 percent slopes 305B Paxton fine sandy loam,3 to 8 116.4 22.4% percent slopes 305C Paxton fine sandy loam,8 to 25.0 4.8% 15 percent slopes 305D Paxton fine sandy loam, 15 to 8.7 1.7% 25 percent slopes 306B Paxton fine sandy loam,0 to 8 1.0 0.2% percent slopes,very stony 306C Paxton fine sandy loam,8 to 2.1 0.4% 15 percent slopes,very stony 306D Paxton fine sandy loam, 15 to 0.0 0.0% 25 percent slopes,very stony 310B Woodbridge fine sandy loam,3 56.5 10.9% to 8 percent slopes 310C Woodbridge fine sandy loam,8 8.2 1.6% to 15 percent slopes 311 B Woodbridge fine sandy loam,0 10.7 2.1% to 8 percent slopes,very stony 405C Charlton fine sandy loam,8 to 1.5 0.3% 15 percent slopes 410B Sutton fine sandy loam,3 to 8 0.2 0.0% percent slopes 421 B Canton fine sandy loam,0 to 8 1.6 0.3% percent slopes,very stony 602 Urban land 217.6 41.9% 651 Udorthents,smoothed 13.8 2.7% 715B Ridgebury and Leicester fine 8.9 1.7% sandy loams,3 to 8 percent slopes,extremely stony Totals for Area of Interest 519.2 100.0% USDA Natural Resources Web Soil Survey 6/27/2023 Conservation Service National Cooperative Soil Survey Page 3 of 3 Attachments PRE-DEVELOPMENT SUBCATCHMENT PLAN POST-DEVELOPMENT SUBCATCHMENT PLAN HYDROCAD WORKSHEETS USGS TOPOGRAPHIC MAP NHESP ENDANGERED SPECIES AND CRITICAL HABITAT MAP FEMA FIRMETTE MAP ASSESSORS ZONING 492 —.—1 z—111 S UTTON 0 STREET —E Noah Anda�z�',M- -echuse�L Home Grown / u Lacrosse, LLC 400 O ,d Street N rth=l,d,N,,MAO]S45 } aV ni { A `� zi HANCOCK -- — V ASSOCIATES / — cmt L"g�,�«s Lzud Su—y— L.'uo,une W q v` ss ———— a PRE DEVELOPMENT SUBCATCHMENT PLAN SCALE -40 PRE 0 60 BO 60 JIB NO.:M"& ASSESSORS —,.11 1;mr ie ZONING 492 SUTTON - R STREET R�5 AI - -"`'__ North Andovzr,Masseohuszhs _ Home Grown Lacrosse, LLC q N�nh AD&-.,MA 01 rid5 HANCOCK \ g �! m9 i` associaTFs IbK hands r y,,,, =a E-,—DR—W 13S ~ uRD S�CHEUSFUD N,as 24 ( u ( ) 17S —_ --- ——— -` Li f _ t of APr m NC BY A x POST DEVELOPMENT SUBCATCHMENT PLAN SCALE, 1"=40' rC ii s OJ-•� 1 40 30 160 SHE-T.2 of 2 1S 2S Overland to Terminal Rd Overland to Old Clark North Rd & Sutton St PRE Subcat Reach and Link Routing Diagram for 27016hyd Prepared by Hancock Associates, Printed 8/30/2023 HydroCAD®10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC 27016nyd Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Area Listing(selected nodes) Area CN Description (sq-ft) (subcatchment-numbers) 107,205 74 >75%Grass cover,Good,HSG C (1S,2S) 27,445 70 Woods,Good,HSG C (1S,2S) 134,650 73 TOTAL AREA 27O16hyd Type///24-hr 2-Year Rainfall=3.15" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Time span=5.00-20.00 hrs,dt=0.05 hrs,301 points Runoff by SCS TR-20 method,UH=SCS,Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 1S:Overland to Terminal Rd North Runoff Area=45,165 sf 0.00%Impervious Runoff Depth>0.86" Flow Length=270' Tc=20.8 min CN=73 Runoff=0.71 cfs 3,232 cf Subcatchment 2S:Overland to Old Clark Rd&Sutton St Runoff Area=89,485 sf 0.00%Impervious Runoff Depth>0.86" Flow Length=570' Tc=24.9 min CN=73 Runoff=1.30 cfs 6,391 cf Total Runoff Area=134,650 sf Runoff Volume=9,623 cf Average Runoff Depth=0.86" 100.00%Pervious=134,650 sf 0.00%Impervious=0 sf 27016hyd Type///24-hr 2-Year Rainfall=3.15" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 @ 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 1S:Overland to Terminal Rd North Runoff = 0.71 cfs @ 12.32 hrs, Volume= 3,232 cf, Depth> 0.86" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 2-Year Rainfall=3.15" Area(sf) CN Description 34,680 74 >75%Grass cover,Good, HSG C 10,485 70 Woods,Good, HSG C 45,165 73 Weighted Average 45,165 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.5 50 0.0100 0.05 Sheet Flow, Woods: Light underbrush n=0.400 P2=3.10" 4.3 220 0.0150 0.86 Shallow Concentrated Flow, Short Grass Pasture Kv=7.0 fps 20.8 270 Total Summary for Subcatchment 2S:Overland to Old Clark Rd&Sutton St Runoff = 1.30 cfs @ 12.38 hrs, Volume= 6,391 cf, Depth> 0.86" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 2-Year Rainfall=3.15" Area(sf) CN Description 72,525 74 >75%Grass cover,Good, HSG C 16,960 70 Woods,Good, HSG C 89,485 73 Weighted Average 89,485 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.5 50 0.0200 0.07 Sheet Flow, Woods:Light underbrush n=0.400 P2=3.10" 12.4 520 0.0100 0.70 Shallow Concentrated Flow, Short Grass Pasture Kv=7.0 fps 24.9 570 Total 27016hyd Type III 24-hr 10-Year Rainfall=4.99" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 @ 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 1S:Overland to Terminal Rd North Runoff = 1.81 cfs @ 12.30 hrs, Volume= 7,869 cf, Depth> 2.09" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 10-Year Rainfall=4.99" Area(sf) CN Description 34,680 74 >75%Grass cover,Good, HSG C 10,485 70 Woods,Good, HSG C 45,165 73 Weighted Average 45,165 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.5 50 0.0100 0.05 Sheet Flow, Woods: Light underbrush n=0.400 P2=3.10" 4.3 220 0.0150 0.86 Shallow Concentrated Flow, Short Grass Pasture Kv=7.0 fps 20.8 270 Total Summary for Subcatchment 2S:Overland to Old Clark Rd&Sutton St Runoff = 3.32 cfs @ 12.36 hrs, Volume= 15,565 cf, Depth> 2.09" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 10-Year Rainfall=4.99" Area(sf) CN Description 72,525 74 >75%Grass cover,Good, HSG C 16,960 70 Woods,Good, HSG C 89,485 73 Weighted Average 89,485 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.5 50 0.0200 0.07 Sheet Flow, Woods:Light underbrush n=0.400 P2=3.10" 12.4 520 0.0100 0.70 Shallow Concentrated Flow, Short Grass Pasture Kv=7.0 fps 24.9 570 Total 27016hyd Type///24-hr 25-Year Rainfall=6.14" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 @ 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 1S:Overland to Terminal Rd North Runoff = 2.57 cfs @ 12.29 hrs, Volume= 11,164 cf, Depth> 2.97" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 25-Year Rainfall=6.14" Area(sf) CN Description 34,680 74 >75%Grass cover,Good, HSG C 10,485 70 Woods,Good, HSG C 45,165 73 Weighted Average 45,165 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.5 50 0.0100 0.05 Sheet Flow, Woods: Light underbrush n=0.400 P2=3.10" 4.3 220 0.0150 0.86 Shallow Concentrated Flow, Short Grass Pasture Kv=7.0 fps 20.8 270 Total Summary for Subcatchment 2S:Overland to Old Clark Rd&Sutton St Runoff = 4.72 cfs @ 12.35 hrs, Volume= 22,086 cf, Depth> 2.96" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 25-Year Rainfall=6.14" Area(sf) CN Description 72,525 74 >75%Grass cover,Good, HSG C 16,960 70 Woods,Good, HSG C 89,485 73 Weighted Average 89,485 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.5 50 0.0200 0.07 Sheet Flow, Woods:Light underbrush n=0.400 P2=3.10" 12.4 520 0.0100 0.70 Shallow Concentrated Flow, Short Grass Pasture Kv=7.0 fps 24.9 570 Total 27016hyd Type///24-hr 100-Year Rainfall=7.91" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 @ 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 1S:Overland to Terminal Rd North Runoff = 3.80 cfs @ 12.29 hrs, Volume= 16,574 cf, Depth> 4.40" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 100-Year Rainfall=7.91" Area(sf) CN Description 34,680 74 >75%Grass cover,Good, HSG C 10,485 70 Woods,Good, HSG C 45,165 73 Weighted Average 45,165 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.5 50 0.0100 0.05 Sheet Flow, Woods: Light underbrush n=0.400 P2=3.10" 4.3 220 0.0150 0.86 Shallow Concentrated Flow, Short Grass Pasture Kv=7.0 fps 20.8 270 Total Summary for Subcatchment 2S:Overland to Old Clark Rd&Sutton St Runoff = 6.98 cfs @ 12.34 hrs, Volume= 32,793 cf, Depth> 4.40" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 100-Year Rainfall=7.91" Area(sf) CN Description 72,525 74 >75%Grass cover,Good, HSG C 16,960 70 Woods,Good, HSG C 89,485 73 Weighted Average 89,485 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.5 50 0.0200 0.07 Sheet Flow, Woods:Light underbrush n=0.400 P2=3.10" 12.4 520 0.0100 0.70 Shallow Concentrated Flow, Short Grass Pasture Kv=7.0 fps 24.9 570 Total 17S 13S Lawn&Woods Porous Pavement 9S A 16R Overland to Terminal Porous Pavement Old Clark Rd&Sutton Rd North expanded resvr Drainage System 14S Roof POST Subcat Reach and Link Routing Diagram for 27016hyd Prepared by Hancock Associates, Printed 8/30/2023 HydroCAD®10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC 27016hyd Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Page 2 Area Listing(selected nodes) Area CN Description (sq-ft) (subcatchment-numbers) 53,505 74 >75%Grass cover,Good,HSG C (9S,17S) 19,240 98 Paved parking and walks,HSG C (13S) 1,175 98 Paved parking,HSG C (9S) 39,100 98 Roofs,HSG C (14S) 21,630 70 Woods,Good,HSG C (9S,17S) 134,650 84 TOTAL AREA 27016hyd Type///24-hr 2-Year Rainfall=3.15" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 9S:Overland to Terminal Rd North Runoff = 0.68 cfs @ 12.10 hrs, Volume= 2,069 cf, Depth> 0.92" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 2-Year Rainfall=3.15" Area(sf) CN Description 16,415 74 >75%Grass cover,Good, HSG C 9,525 70 Woods,Good,HSG C 1,175 98 Paved parking, HSG C 27,115 74 Weighted Average 25,940 95.67%Pervious Area 1,175 4.33%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment 135: Porous Pavement Runoff = 0.11 cfs @ 19.29 hrs, Volume= 1,943 cf, Depth> 1.21" Routed to Pond 13P:Porous Pavement expanded resvr Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 2-Year Rainfall=3.15" Area(sf) CN Description * 19,240 98 Paved parking and walks,HSG C 19,240 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 597.0 Direct Entry,790min/41"Porous Lag time Summary for Subcatchment 145: Roof Runoff = 2.68 cfs @ 12.09 hrs, Volume= 8,888 cf, Depth> 2.73" Routed to Pond 13P:Porous Pavement expanded resvr Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 2-Year Rainfall=3.15" Area(sf) CN Description 39,100 98 Roofs,HSG C 39,100 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, 27016hyd Type///24-hr 2-Year Rainfall=3.15" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 17S: Lawn&Woods Runoff = 1.16 cfs @ 12.10 hrs, Volume= 3,544 cf, Depth> 0.86" Routed to Reach 16R:Old Clark Rd&Sutton Drainage System Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 2-Year Rainfall=3.15" Area(sf) CN Description 12,105 70 Woods,Good, HSG C 37,090 74 >75%Grass cover,Good, HSG C 49,195 73 Weighted Average 49,195 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Reach 16R:Old Clark Rd&Sutton Drainage System Inflow Area= 107,535 sf, 54.25%Impervious, Inflow Depth> 0.40" for 2-Year event Inflow = 1.16 cfs @ 12.10 hrs, Volume= 3,544 cf Outflow = 1.16 cfs @ 12.10 hrs, Volume= 3,544 cf, Atten=0%, Lag=0.0 min Routing by Dyn-Stor-Ind method,Time Span=5.00-20.00 hrs,dt=0.05 hrs Summary for Pond 13P: Porous Pavement expanded resvr Inflow Area= 58,340 sf,100.00%Impervious, Inflow Depth> 2.23" for 2-Year event Inflow = 2.69 cfs @ 12.09 hrs, Volume= 10,831 cf Outflow = 0.47 cfs @ 11.80 hrs, Volume= 10,857 cf, Atten=83%, Lag=0.0 min Discarded = 0.47 cfs @ 11.80 hrs, Volume= 10,857 cf Primary = 0.00 cfs @ 5.00 hrs, Volume= 0 cf Routed to Reach 16R:Old Clark Rd&Sutton Drainage System Routing by Dyn-Stor-Ind method,Time Span=5.00-20.00 hrs,dt=0.05 hrs Peak Elev=159.21'@ 12.55 hrs Surf.Area=19,890 sf Storage=2,437 cf Plug-Flow detention time=(not calculated:outflow precedes inflow) Center-of-Mass det.time=25.8 min(814.9-789.1) Volume Invert Avail.Storage Storage Description #1 158.90' 7,320 cf Custom Stage Data(Prismatic)Listed below(Recalc) 18,299 cf Overall x 40.0%Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 158.90 19,890 0 0 159.57 19,890 13,326 13,326 159.82 19,890 4,973 18,299 Device Routing Invert Outlet Devices #1 Discarded 158.90' 1.020 in/hr Exfiltration over Surface area #2 Device 3 159.52' 4.0'long Sharp-Crested Rectangular Weir 2 End Contraction(s) #3 Primary 156.10' 12.0" Round Culvert L=136.0' CPP,projecting,no headwall, Ke=0.900 27016hyd Type///24-hr 2-Year Rainfall=3.15" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Page 6 Inlet/Outlet Invert=156.10'/150.20' S=0.0434'/' Cc=0.900 n=0.012 Corrugated PP,smooth interior, Flow Area=0.79 sf Discarded OutFlow Max=0.47 cfs @ 11.80 hrs HW=158.91' (Free Discharge) t1=Exfiltration (Exfiltration Controls 0.47 cfs) Primary OutFlow Max=0.00 cfs @ 5.00 hrs HW=158.90' TW=0.00' (Dynamic Tailwater) t3=Culvert (Passes 0.00 cfs of 4.53 cfs potential flow) t2=Sharp-Crested Rectangular Weir (Controls 0.00 cfs) 27016hyd Type III 24-hr 10-Year Rainfall=4.99" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Summary for Subcatchment 9S:Overland to Terminal Rd North Runoff = 1.68 cfs @ 12.09 hrs, Volume= 4,933 cf, Depth> 2.18" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 10-Year Rainfall=4.99" Area(sf) CN Description 16,415 74 >75%Grass cover,Good, HSG C 9,525 70 Woods,Good,HSG C 1,175 98 Paved parking, HSG C 27,115 74 Weighted Average 25,940 95.67%Pervious Area 1,175 4.33%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment 135: Porous Pavement Runoff = 0.18 cfs @ 19.27 hrs, Volume= 3,236 cf, Depth> 2.02" Routed to Pond 13P:Porous Pavement expanded resvr Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 10-Year Rainfall=4.99" Area(sf) CN Description * 19,240 98 Paved parking and walks,HSG C 19,240 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 597.0 Direct Entry,790min/41"Porous Lag time Summary for Subcatchment 145: Roof Runoff = 4.28 cfs @ 12.09 hrs, Volume= 14,368 cf, Depth> 4.41" Routed to Pond 13P:Porous Pavement expanded resvr Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 10-Year Rainfall=4.99" Area(sf) CN Description 39,100 98 Roofs,HSG C 39,100 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, 27016hyd Type III 24-hr 10-Year Rainfall=4.99" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Summary for Subcatchment 17S: Lawn&Woods Runoff = 2.93 cfs @ 12.10 hrs, Volume= 8,619 cf, Depth> 2.10" Routed to Reach 16R:Old Clark Rd&Sutton Drainage System Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 10-Year Rainfall=4.99" Area(sf) CN Description 12,105 70 Woods,Good, HSG C 37,090 74 >75%Grass cover,Good, HSG C 49,195 73 Weighted Average 49,195 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Reach 16R:Old Clark Rd&Sutton Drainage System Inflow Area= 107,535 sf, 54.25%Impervious, Inflow Depth> 0.96" for 10-Year event Inflow = 2.93 cfs @ 12.10 hrs, Volume= 8,624 cf Outflow = 2.93 cfs @ 12.10 hrs, Volume= 8,624 cf, Atten=0%, Lag=0.0 min Routing by Dyn-Stor-Ind method,Time Span=5.00-20.00 hrs,dt=0.05 hrs Summary for Pond 13P: Porous Pavement expanded resvr Inflow Area= 58,340 sf,100.00%Impervious, Inflow Depth> 3.62" for 10-Year event Inflow = 4.30 cfs @ 12.09 hrs, Volume= 17,604 cf Outflow = 0.47 cfs @ 12.81 hrs, Volume= 17,619 cf, Atten=89%, Lag=43.5 min Discarded = 0.47 cfs @ 11.65 hrs, Volume= 17,614 cf Primary = 0.00 cfs @ 12.81 hrs, Volume= 5 cf Routed to Reach 16R:Old Clark Rd&Sutton Drainage System Routing by Dyn-Stor-Ind method,Time Span=5.00-20.00 hrs,dt=0.05 hrs Peak Elev=159.53'@ 12.81 hrs Surf.Area=19,890 sf Storage=4,973 cf Plug-Flow detention time=(not calculated:outflow precedes inflow) Center-of-Mass det.time=72.7 min(858.5-785.8) Volume Invert Avail.Storage Storage Description #1 158.90' 7,320 cf Custom Stage Data(Prismatic)Listed below(Recalc) 18,299 cf Overall x 40.0%Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 158.90 19,890 0 0 159.57 19,890 13,326 13,326 159.82 19,890 4,973 18,299 Device Routing Invert Outlet Devices #1 Discarded 158.90' 1.020 in/hr Exfiltration over Surface area #2 Device 3 159.52' 4.0'long Sharp-Crested Rectangular Weir 2 End Contraction(s) #3 Primary 156.10' 12.0" Round Culvert L=136.0' CPP,projecting,no headwall, Ke=0.900 27016hyd Type III 24-hr 10-Year Rainfall=4.99" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Inlet/Outlet Invert=156.10'/150.20' S=0.0434'/' Cc=0.900 n=0.012 Corrugated PP,smooth interior, Flow Area=0.79 sf Discarded OutFlow Max=0.47 cfs @ 11.65 hrs HW=158.91' (Free Discharge) t1=Exfiltration (Exfiltration Controls 0.47 cfs) Primary OutFlow Max=0.00 cfs @ 12.81 hrs HW=159.53' TW=0.00' (Dynamic Tailwater) t3=Culvert (Passes 0.00 cfs of 5.11 cfs potential flow) t2=Sharp-Crested Rectangular Weir (Weir Controls 0.00 cfs @ 0.23 fps) 27016hyd Type///24-hr 25-Year Rainfall=6.14" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Summary for Subcatchment 9S:Overland to Terminal Rd North Runoff = 2.36 cfs @ 12.09 hrs, Volume= 6,951 cf, Depth> 3.08" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 25-Year Rainfall=6.14" Area(sf) CN Description 16,415 74 >75%Grass cover,Good, HSG C 9,525 70 Woods,Good,HSG C 1,175 98 Paved parking, HSG C 27,115 74 Weighted Average 25,940 95.67%Pervious Area 1,175 4.33%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment 135: Porous Pavement Runoff = 0.23 cfs @ 19.27 hrs, Volume= 4,049 cf, Depth> 2.53" Routed to Pond 13P:Porous Pavement expanded resvr Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 25-Year Rainfall=6.14" Area(sf) CN Description * 19,240 98 Paved parking and walks,HSG C 19,240 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 597.0 Direct Entry,790min/41"Porous Lag time Summary for Subcatchment 145: Roof Runoff = 5.28 cfs @ 12.09 hrs, Volume= 17,779 cf, Depth> 5.46" Routed to Pond 13P:Porous Pavement expanded resvr Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 25-Year Rainfall=6.14" Area(sf) CN Description 39,100 98 Roofs,HSG C 39,100 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, 27016hyd Type 11124-hr 25-Year Rainfall=6.14" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Summary for Subcatchment 17S: Lawn&Woods Runoff = 4.16 cfs @ 12.09 hrs, Volume= 12,223 cf, Depth> 2.98" Routed to Reach 16R:Old Clark Rd&Sutton Drainage System Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 25-Year Rainfall=6.14" Area(sf) CN Description 12,105 70 Woods,Good, HSG C 37,090 74 >75%Grass cover,Good, HSG C 49,195 73 Weighted Average 49,195 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Reach 16R:Old Clark Rd&Sutton Drainage System Inflow Area= 107,535 sf, 54.25%Impervious, Inflow Depth> 1.54" for 25-Year event Inflow = 4.16 cfs @ 12.09 hrs, Volume= 13,815 cf Outflow = 4.16 cfs @ 12.09 hrs, Volume= 13,815 cf, Atten=0%, Lag=0.0 min Routing by Dyn-Stor-Ind method,Time Span=5.00-20.00 hrs,dt=0.05 hrs Summary for Pond 13P: Porous Pavement expanded resvr Inflow Area= 58,340 sf,100.00%Impervious, Inflow Depth> 4.49" for 25-Year event Inflow = 5.30 cfs @ 12.09 hrs, Volume= 21,827 cf Outflow = 1.12 cfs @ 12.51 hrs, Volume= 20572 cf, Atten=79%, Lag=25.2 min Discarded = 0.47 cfs @ 11.50 hrs, Volume= 18,980 cf Primary = 0.65 cfs @ 12.51 hrs, Volume= 1591 cf Routed to Reach 16R:Old Clark Rd&Sutton Drainage System Routing by Dyn-Stor-Ind method,Time Span=5.00-20.00 hrs,dt=0.05 hrs Peak Elev=159.66'@ 12.51 hrs Surf.Area=19,890 sf Storage=6,017 cf Plug-Flow detention time=84.4 min calculated for 20,572 cf(94%of inflow) Center-of-Mass det.time=61.1 min(845.8-784.8) Volume Invert Avail.Storage Storage Description #1 158.90' 7,320 cf Custom Stage Data(Prismatic)Listed below(Recalc) 18,299 cf Overall x 40.0%Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 158.90 19,890 0 0 159.57 19,890 13,326 13,326 159.82 19,890 4,973 18,299 Device Routing Invert Outlet Devices #1 Discarded 158.90' 1.020 in/hr Exfiltration over Surface area #2 Device 3 159.52' 4.0'long Sharp-Crested Rectangular Weir 2 End Contraction(s) #3 Primary 156.10' 12.0" Round Culvert L=136.0' CPP,projecting,no headwall, Ke=0.900 27016hyd Type 11124-hr 25-Year Rainfall=6.14" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Inlet/Outlet Invert=156.10'/150.20' S=0.0434'/' Cc=0.900 n=0.012 Corrugated PP,smooth interior, Flow Area=0.79 sf Discarded OutFlow Max=0.47 cfs @ 11.50 hrs HW=158.91' (Free Discharge) t1=Exfiltration (Exfiltration Controls 0.47 cfs) Primary OutFlow Max=0.65 cfs @ 12.51 hrs HW=159.66' TW=0.00' (Dynamic Tailwater) t3=Culvert (Passes 0.65 cfs of 5.22 cfs potential flow) t2=Sharp-Crested Rectangular Weir (Weir Controls 0.65 cfs @ 1.21 fps) 27016hyd Type///24-hr 100-Year Rainfall=7.91" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Summary for Subcatchment 9S:Overland to Terminal Rd North Runoff = 3.46 cfs @ 12.09 hrs, Volume= 10,251 cf, Depth> 4.54" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 100-Year Rainfall=7.91" Area(sf) CN Description 16,415 74 >75%Grass cover,Good, HSG C 9,525 70 Woods,Good,HSG C 1,175 98 Paved parking, HSG C 27,115 74 Weighted Average 25,940 95.67%Pervious Area 1,175 4.33%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment 135: Porous Pavement Runoff = 0.29 cfs @ 19.27 hrs, Volume= 5,303 cf, Depth> 3.31" Routed to Pond 13P:Porous Pavement expanded resvr Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 100-Year Rainfall=7.91" Area(sf) CN Description * 19,240 98 Paved parking and walks,HSG C 19,240 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 597.0 Direct Entry,790min/41"Porous Lag time Summary for Subcatchment 145: Roof Runoff = 6.81 cfs @ 12.09 hrs, Volume= 23,014 cf, Depth> 7.06" Routed to Pond 13P:Porous Pavement expanded resvr Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 100-Year Rainfall=7.91" Area(sf) CN Description 39,100 98 Roofs,HSG C 39,100 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, 27016hyd Type11124-hr 100-year Rainfall=7.91" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Summary for Subcatchment 17S: Lawn&Woods Runoff = 6.13 cfs @ 12.09 hrs, Volume= 18,139 cf, Depth> 4.42" Routed to Reach 16R:Old Clark Rd&Sutton Drainage System Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=5.00-20.00 hrs,dt=0.05 hrs Type III 24-hr 100-Year Rainfall=7.91" Area(sf) CN Description 12,105 70 Woods,Good, HSG C 37,090 74 >75%Grass cover,Good, HSG C 49,195 73 Weighted Average 49,195 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Reach 16R:Old Clark Rd&Sutton Drainage System Inflow Area= 107,535 sf, 54.25%Impervious, Inflow Depth> 2.56" for 100-Year event Inflow = 6.15 cfs @ 12.10 hrs, Volume= 22,978 cf Outflow = 6.15 cfs @ 12.10 hrs, Volume= 22,978 cf, Atten=0%, Lag=0.0 min Routing by Dyn-Stor-Ind method,Time Span=5.00-20.00 hrs,dt=0.05 hrs Summary for Pond 13P: Porous Pavement expanded resvr Inflow Area= 58,340 sf,100.00%Impervious, Inflow Depth> 5.82" for 100-Year event Inflow = 6.84 cfs @ 12.09 hrs, Volume= 28,317 cf Outflow = 2.34 cfs @ 12.37 hrs, Volume= 24,998 cf, Atten=66%, Lag=16.8 min Discarded = 0.47 cfs @ 11.15 hrs, Volume= 20,159 cf Primary = 1.87 cfs @ 12.37 hrs, Volume= 4,838 cf Routed to Reach 16R:Old Clark Rd&Sutton Drainage System Routing by Dyn-Stor-Ind method,Time Span=5.00-20.00 hrs,dt=0.05 hrs Peak Elev=159.80'@ 12.37 hrs Surf.Area=19,890 sf Storage=7,128 cf Plug-Flow detention time=81.9 min calculated for 24,998 cf(88%of inflow) Center-of-Mass det.time=35.8 min(819.6-783.8) Volume Invert Avail.Storage Storage Description #1 158.90' 7,320 cf Custom Stage Data(Prismatic)Listed below(Recalc) 18,299 cf Overall x 40.0%Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 158.90 19,890 0 0 159.57 19,890 13,326 13,326 159.82 19,890 4,973 18,299 Device Routing Invert Outlet Devices #1 Discarded 158.90' 1.020 in/hr Exfiltration over Surface area #2 Device 3 159.52' 4.0'long Sharp-Crested Rectangular Weir 2 End Contraction(s) #3 Primary 156.10' 12.0" Round Culvert L=136.0' CPP,projecting,no headwall, Ke=0.900 27016hyd Typelll24-hr 100-YearRainfall=7.91" Prepared by Hancock Associates Printed 8/30/2023 HydroCAD°10.20-3c s/n 00711 ©2023 HydroCAD Software Solutions LLC Inlet/Outlet Invert=156.10'/150.20' S=0.0434'/' Cc=0.900 n=0.012 Corrugated PP,smooth interior, Flow Area=0.79 sf Discarded OutFlow Max=0.47 cfs @ 11.15 hrs HW=158.91' (Free Discharge) t1=Exfiltration (Exfiltration Controls 0.47 cfs) Primary OutFlow Max=1.86 cfs @ 12.37 hrs HW=159.80' TW=0.00' (Dynamic Tailwater) t3=Culvert (Passes 1.86 cfs of 5.34 cfs potential flow) t2=Sharp-Crested Rectangular Weir (Weir Controls 1.86 cfs @ 1.71 fps) !1 1(�/�[� U.S.DEPARTMENT OF THE INTERIOR m, SOUTH GROVELAND QUADRANGLE MUSGS U.S.GEOLOGICAL SURVEY Y�4" MSSACMUSETTS-ESSEN COUNTY US Topo 1.-.LNUTC 11AIEi u r `M Mtrri UFN am4a, u .TOWN 33 Mo nr,R oq l \ a y me raamu+�,, r p'a ✓ u ✓ _ ✓✓ 5 LOCUS 31 30 0 ,e�H r _ � wx '..H. E o , ` ✓N ��r.. �� i oa x ✓"�, "� „„� " w � I 17 4 i ✓ y✓ w s e e � ✓ u. E ,un � j i r 11 ✓ e N 1e t � v ea survrry SCALE 124000 d' wnu unsr AT ory mmmm. .n..a. o.w SOUTH GROVE AND,MA NHESP Priority Habitats of Rare Species NHESP Estimated Habitats of Rare Wildlife a V � Property Tax Parcels M -- a s . z IM ..� ,NIA z 46 m x. -q*ad Hip , _ TaN a s- ' "Pig _ s a� t -14 z- National Flood Hazard Layer FIRMette FEMA Legend 71°T25"W 42°43'3"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT Without Base Flood Elevation(BFE) \\ y SPECIAL FLOOD _ zf,\ With BFE or DepthZcnaAe,AO,AYc',Ak AZARD H`� _ ` AREAS Regulatory Floodway 0. %Annual Chance Flood Hazard,Areas of 1/o annual chance flood with average „ depth less than one foot or with drainage areas of less than one square mile Z-e X own mmk\\ Future Conditions 1%Annual Ilk Chance Flood Hazard — Area with Reduced Flood Risk due to o`g OTHER AREAS OF Levee.See Notes.z-e x HAZARD FLOOD �\ ,� A Area with Flood Risk due to Levee Z-e ��\ AAA\ � � Area of Minimal Flood Hazard _ Effective LOMR NO SCREEN F ��-AP OTHER AREAS Area of Undetermined Flood Hazard -_ GENERAL -—-` Channel,Culvert,or Storm Sewer STRUCTURES I 1 1 I 1 1 I Levee,Dike,or Floodwall \ a zo.z Cross Sections with l°lo Annual Chance `\\ \\ �zs Water Surface Elevation AREKOF-MNIM\\ v ` \ � � a - Coastal Transect s,— Base Flood Elevation Line BFE Limit of Study �( i �� � .' Jurisdiction Boundary Coastal Transect Baseline \\ \ \ --)5W98 OTHER g Profile Baseline FEATURES Hydrographic Feature Digital Data Available N No Digital Data Available \ . \ MAP PANEL Unmapped Lk The pin displayed on the map is an approximate _ point selected by the user and does not represent �. an authoritative property location_ Nk This map complies with FEMA's standards for the use of g M� y `�` _ digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards v The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA_This map was exported on 8/21/2023 of 2:50 PM and does not reflect changes or amendments subsequent to this date and �.:. time.The NFHL and effective information may change or become superseded by new data overtime. This map image is void if the one or more of the following map elements do not appear:basemap imagery,flood zone labels, legend,scale bar,map creation date,community identifiers, 71°6'47"W 42°42'36"N FIRM panel number,and FIRM effective date.Map images for Feet 1:6 000 unmapped and unmodernized areas cannot be used for 0 250 500 1,000 1,500 2,000 regulatory purposes. Basemap Imagery Source:USGS National Map 2023