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HomeMy WebLinkAboutStormwater Report Rev June 2022 Stormwater Report Warehouse & Distribution Center Alterations 225 White’s Path Yarmouth, Massachusetts CHA Project Number: 072846 Applicant: Two Twenty Five White’s Path Units Two and Three, LLC 231 Willow Street Yarmouthport, MA 02675 Prepared by: 141 Longwater Drive, Suite 104 Norwell, Massachusetts 02061 Phone: (781) 982-5400 Fax: (781) 982-5490 May, 2022 Revised June, 2022 Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report TABLE OF CONTENTS 1.0 NARRATIVE .................................................................................................................................. 1.1 Executive Summary ......................................................................................................... 1.2 Objective of Calculations.................................................................................................. 1.3 Methodology .................................................................................................................... 1.4 Site Hydrology ................................................................................................................. 1.4.1 Estimated Seasonal High Groundwater................................................................. 1.4.2 Pre-Development Hydrology ................................................................................ 1.4.3 Post-Development Hydrology ……………………………………………………. 1.5 Stormwater Management .................................................................................................. 1.5.1 MassDEP Stormwater Management Standards…………………………………… 1.5.2 Yarmouth Stormwater Management Standards…………………………………… 1.6 Best Management Practices .............................................................................................. 1.7 Hydraulics and Pipe Sizing ............................................................................................... 1.8 Summary of Hydrology & Stormwater Calculations ......................................................... 1.9 Conclusion ....................................................................................................................... 1.10 References........................................................................................................................ 1.11 General Construction Sequencing ..................................................................................... 1.12 Figures: ............................................................................................................................ Figure 1: Orthophoto Plan……………………….……………………………… Figure 2: USGS Plan ………………………...………………………………… Figure 3: NHESP Habitiat Map…………….…………………………………… Figure 4: FEMA Flood Mp……………………………………………………… 2.0 LONG-TERM POLLUTION PREVENTION AND OPERATION &MAINTENANCE PLAN 2.1 Long-Term Pollution Prevention and Operation & Maintenance Narrative ........................ BMP Plan ......................................................................................................................... 2.2 Construction Period Operation & Maintenance Narrative .................................................. BMP Plan ......................................................................................................................... 3.0 HYDROLOGY AND HYDRAULIC MODELING ................................................................................... 3.1 HydroCAD Site Hydrology Calculations .......................................................................... 3.1.1 Pre-Developed Stormwater Report Calculations ................................................... 3.1.2 Post-Developed Stormwater Report Calculations ................................................. 3.2 Proposed Pipe Hydraulic Calculations .............................................................................. 3.2.1 Pipe Network Capacity Calculations .................................................................... 3.2.2 Catch Basin Area Plan (DA-003) 3.2.3 Post-Developed Stormwater Report Calculations Tailwater 25-Year 3.3 Drainage Area Plans ......................................................................................................... 3.3.1 Existing Conditions Hydrology (DA-001) ............................................................ 3.3.2 Proposed Conditions Hydrology (DA-002) ........................................................... 4.0 STORMWATER MANAGEMENT CALCULATIONS .............................................................................. 4.1 Water Quality ................................................................................................................... 4.2 Total Suspended Solids (TSS) Removal Calculations ........................................................ 4.3 Required Recharge Volume .............................................................................................. 4.4 Drawdown Time Calculations........................................................................................... 4.5 Illicit Discharge Statement ................................................................................................ 5.0 STORMWATER CHECKLIST ............................................................................................................ Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report LIST OF APPENDICES Appendix A Custom Soil Resource Report Test Pit Data LIST OF ACRONYMS & ABBREVIATIONS BFE Base Flood Elevation BMP Best Management Practice BVW Bordering Vegetated Wetland FEMA Federal Emergency Management Agency FIRM Flood Insurance Rate Map HSG Hydrologic Soil Group IWPA Interim Wellhead Protection Area MAHW Mean Annual High-Water MassDEP Massachusetts Department of Environmental Protection NAVD North American Vertical Datum NRCS Natural Resources Conservation Service SHGW Seasonal High Groundwater SWMSH Stormwater Management Standards Handbook Tc Time of Concentration TSS Total Suspended Solids USGS United States Geological Survey Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report 1.0 NARRATIVE 1.1 EXECUTIVE SUMMARY The project proponent, 225 White’s Path Unit Two and Unit Three, LLC, proposes to redevelop the existing warehouse/distribution center building and parking/loading facilities on the property at 225 White’s Path, Yarmouth, MA. The site consists of a single parcel containing 17.7 acres. The existing building is a single-story, steel and masonry structure, having an approximate footprint of 156,000 square-feet. The building is subdivided into three (3) condominium units, two (2) of which, will be renovated as part of the proposed project. There are no changes to the building footprint proposed. A single driveway access from White’s Path is located in the northwest corner of the property. Paved parking for automobiles and loading areas for trailers are located in the westerly and southerly portions of the site, adjacent to the centrally located building. The remaining portions of the site consist of naturally wooded areas and landscaping. Existing drainage systems on site are comprised of closed-conveyance pipe systems which collect and convey stormwater runoff from paved surfaces to two (2) open retention/recharge basins. These basins completely contain, and recharge collected site runoff as there are no outlets from the basins. They have performed effectively for over twenty years. The proposed project generally consists of upgrading the interiors of Units 2 and 3 and improving parking and loading areas of the site. Two (2) areas reserved for trailers and one (1) area reserved for vans will be added to the site, increasing the impervious surface area by approximately 35,000 square feet. The proposed site layout requires relocation of the existing retention/recharge basins to the southeast portion of the property. Upgrades to the stormwater conveyance systems are proposed to manage runoff from new and existing paved surfaces to comply with the Town Yarmouth Stormwater Management Bylaw, Chapter 145 and the Massachusetts Department of Environmental Protection (MassDEP) Stormwater Management Standards. These upgrades include deep sump hooded catch basins, proprietary water quality inlet, and a replacement retention/recharge basin that is designed to retain the runoff volume generated by the 100-year storm. 1.2 OBJECTIVE OF CALCULATIONS The purpose of this stormwater report and analysis is to assess and quantify proposed stormwater runoff conditions from the site based upon the Massachusetts Department of Environmental Protection (MassDEP) Stormwater Management Standards and the applicable provisions of the Town of Yarmouth Stormwater Management Regulations. The goal of the proposed stormwater management system design is to continue to use components Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report of the existing system where appropriate, supplemented with new stormwater Best Management Practices (BMPs), including a replacement retention/recharge basin, to improve water quality, maximize infiltration, and to protect the surrounding area from flooding impacts. Stormwater routing calculations are performed using the 2-year, 10-year, 25-year, 50-year, and 100-year frequency. Type III, 24-hour SCS design storms to demonstrate compliance with the Regulations. 1.3 METHODOLOGY The HydroCAD Stormwater Modeling System computer program, version 10.0, by Applied Microcomputer Systems, Inc. is used to develop stormwater runoff rates and volumes for the proposed conditions at the project site. The HydroCAD software is a hydrograph generation and routing program similar to TR-20. The software uses Soil Conservation Service (SCS) Unit Hydrograph Methodology. This drainage analysis was developed utilizing a Type III, 24-hour storm as developed by the Soil Conservation Service (SCS). Information regarding the equations and calculation procedures utilized in HydroCAD will be made available upon request. The following basic steps are employed in the procedure: 1.A rainfall distribution is selected which indicates how the storm depth will be distributed over time. This is the standardized Type III SCS distribution based upon the project’s location. 2.The design storm depth is determined from rainfall frequency atlas based upon the return period being modeled. Combined with the distribution of rainfall will yield the cumulative depth at each period during the storm. 3.Based upon the Time of Concentration (Tc), the storm is divided into bursts of equal duration. For each burst, the SCS runoff equation and the average Curve Number are used to determine the portion of that burst that will appear as runoff. 4.A unit hydrograph representing the runoff resulting from one inch of precipitation excess generated uniformly over the watershed in conduction with the Time of Concentration is used to determine how the runoff from a burst is distributed over time. The result is a runoff hydrograph for a single burst. 5.Individual hydrographs are added together for all bursts in the storm yielding the complete runoff hydrograph for each storm. The SCS rainfall distributions are derived from observations that were used to develop the Intensity-Duration-Frequency relationship or IDF curve. By studying the Weather Bureau’s Rainfall Frequency Atlases, the SCS developed four “mass curves” that could be used to represent Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report the characteristics of the rainfall distribution throughout the continental United States. The mass curve is a dimensionless distribution of rainfall over time, which indicates the fraction of the rainfall event that occurs at a given time within a 24-hour precipitation event. This synthetic distribution develops peak rates for storms of varying durations and intensities. The SCS distribution provides a cumulative rainfall at any point in time and allows volume dependent routing runoff calculations to occur. The HydroCAD software has the additional capability to describe shallow concentrated flow. The “NEH-4 Upland Method” included in the HydroCAD software is applicable for conditions which occur in the headwaters of a watershed up to 2000 acres. The NEH-4 Upland Method allows the Time of Concentration (Tc) to reflect ground conditions such as overland flow, grassed waterways, paved areas and upland gullies. This results in a model that more accurately reflects the ground surface for shallow concentrated flow conditions, than TR-20, which is limited to distinguishing only paved and unpaved surfaces. Tc is the time required for water to flow from the most hydraulically distant point on a runoff area to the measurement or collection point. In instances where the watersheds are small and impervious, Tc has been directly entered as a 5-minute minimum. This is consistent with standard engineering practice and Technical Release (TR-55) Urban Hydrology for Small Watersheds graphical method. A lower boundary of 5 minutes will yield a conservative, yet practical measure of stormwater runoff flow for small watersheds contained within the development. The curve number or CN is a land sensitive coefficient that dictates the relationship between total rainfall depth and direct stormwater runoff. Based upon the cover in each sub-watershed a weighted average CN value was determined. The area, CN values, and time of concentration were entered into HydroCAD to develop hydrographs for post developed conditions. 1.4 SITE HYDROLOGY Hydrologic soil groups (HSG) are used to estimate runoff potential from precipitation in hydrology calculations. HSG designations vary from “A” to “D” with “A” having the highest infiltration rate and lowest runoff potential and “D” the slowest infiltration rate and highest runoff potential. Soils within the property have been classified by the USDA Soil Conservation Service as: Urban Land in the northerly and easterly portions of the property, primarily in the developed areas, and Carver, coarse sand in the remaining portions of the property. Urban land classification generally results from a disturbed soil profile because of development and the applicable HSG is dependent on the texture of the new surface soil. In this case, since surface cover of the Urban Land component consists primarily of paved surfaces, the estimated runoff from this area will not vary with HSG. Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report The Carver soil component is classified as HSG “A”, a soil with low runoff potential and high infiltration rate. Test pits confirm the presence of permeable, sandy soil in the western portion of the site, consistent with the HSG “A” classification. An infiltration rate of 8.27 inches per hour, is utilized,in the HydroCAD calculations for the recharge component of the proposed retention/recharge basin. The following design storm frequencies and corresponding rainfall depths were compiled from the NOAA National Weather Service “NOAA Atlas 14” and are used in the HydroCAD model: Storm Frequency (Years) Rainfall Depth (Inches) 2 3.35 10 4.87 25 5.82 50 6.54 100 7.28 Drainage watershed plans for both pre- and post-development conditions have been included in Section 3.3 of this report. 1.4.1 ESTIMATED SEASONAL HIGH GROUNDWATER Seasonal high groundwater represents the highest groundwater elevation. Depth to seasonal high groundwater may be identified based on redoximorphic (redox) features in the soil, if present, or by application of the Cape Cod Commission adjustment method (Cape Cod Commission Technical Bulletin 92-001). Four (4) test pits were advanced in the area of the proposed retention/recharge basin to confirm soils and seasonal high groundwater elevation. The test pits varied in depth from 15 to 16.5 feet. Redoximorphic features were not observed in any of the test pits so that the Cape Cod Commission adjustment method is applied to establish the depth to seasonal high groundwater. Test pit data and groundwater adjustment calculations based on Technical Bulletin 92-001 are included in Appendix A of this Stormwater Report. 1.4.2 PRE-DEVELOPMENT HYDROLOGY As noted above, the developed the southerly and westerly portion of the site is served by a stormwater management system that includes catch basins, manholes, water quality structures, and pipe conveyances that ultimately discharge runoff into two (2) retention/recharge basins. Since there are no other outlets or discharges from these basins, Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report they entirely contain site generated runoff until it is infiltrated into the surrounding soils. These basins have effectively managed site runoff since their installation. Roof runoff is collected in a closed system consisting of rooftop scuppers and internal roof drains that convey rooftop runoff to a recharge system located near the southeast corner of the building. This system collects rooftop runoff only and is an independent system that will continue to serve the same function under proposed conditions. The areas north and east of the building are undeveloped with naturally wooded and landscaped areas. These areas of the site will not be altered by the proposed project so that their hydrology will not change. Refer to the Existing Conditions Hydrology Plan (DA- 002) which is included in Section 3.3.2 of this report. Existing Conditions Subcatchment 2S Subcatchment 2S consists of the portion of the site which drains southerly to one of the retention/recharge basins onsite. Much of the surface is paved with areas of woods, landscaping, and grass. A 13-minute Tc was utilized. Existing Conditions Subcatchment 3S Subcatchment 3S consists of the portion of the site which drains westerly. Cover consists entirely of woods. A 17-minute Tc was utilized. Existing Conditions Subcatchment 4S Subcatchment 4S consists of the portion of the site which drains to one of the retention/recharge basins onsite. Most of the surface is paved with areas of woods, landscaping, and grass. A 29-minute Tc was utilized. Existing Conditions Subcatchment 5S Subcatchment 5S consists of the portion of the site which drains southerly towards the Cape Cod Rail Trail. The majority of the surface is landscaping and grass with areas of woods. A 14-minute Tc was utilized. 1.4.3 POST-DEVELOPMENT HYDROLOGY The proposed project includes interior improvements to the existing warehouse/distribution center building and site upgrades to serve the new facility. As previously described, these site improvements are primarily located westerly and southerly of the building. Consequently, only the subcatchment areas that are altered by the proposed project are analyzed. These sub-watershed areas, 2S, 3S, and 4S are depicted on the Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report Proposed Conditions Hydrology Plan (DA-002) which is included in Section 3.3.2 of this report. Post Development Subcatchment 2S/4S Subcatchment 2S/4S is a combination of subcatchments 2S and 4S. This subcatchment consists of the larger portion of the site in which improvements are proposed. Impervious surface is expected to increase by approximately 35,000 square feet within this area. Existing stormwater BMP’s and conveyances will be replaced and/or rerouted. New BMP’s and conveyances are proposed including deep sump/hooded catch basins, a proprietary water quality unit, and replacement recharge/retention basin. Runoff generated from this area will be collected and treated prior to discharge to the proposed recharge/retention basin. A time of concentration of 6 minutes is used in the analysis for this subcatchment area. Post Development Subcatchment 3S Subcatchment 3S consists of the portion of the site which drains westerly. The area consists entirely of woods, as it did in the predevelopment case, but has been reduced in size due to the proposed development. A 16-minute Tc was utilized. Post Development Subcatchment 5S Subcatchment 5S consists of the portion of the site which is tributary southerly towards the Cape Cod Rail Trail. Most of the surface cover consists of landscaping and grass with areas of woods, as it did in the predevelopment case. Subcatchment 5S remains the same size post development. A 14-minute Tc was utilized. 1.5 STORMWATER MANAGEMENT This project includes a Stormwater Management System that has been designed to satisfy and comply with the requirements of the MassDEP Stormwater Standards (2008) and the Town of Yarmouth Stormwater Regulations. The following is an explanation on how the proposed project will comply with these regulations. 1.5.1 MassDEP STORMWATER MANAGEMENT STANDARDS MassDEP Stormwater Standard 1: No New Untreated Discharges –No new stormwater system conveyances will discharge untreated runoff or cause erosion in wetlands or waters of the Commonwealth. All new stormwater system conveyances will be treated prior to discharge and will Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report not cause erosion in wetlands or waters of the Commonwealth. Stormwater will be directed to various structural and non-structural Best Management Practices, including an onsite retention/recharge basin that will contain all new stormwater discharges. MassDEP Stormwater Standard 2: Peak Rate Attenuation –Stormwater management systems shall be designed so that post-development peak discharge rates do not exceed pre-development peak discharge rates. Pre-development and post-development peak discharge rates and volumes are calculated with the aid of a hydrograph routing program using TR-20 methodology called HydroCAD. The calculations demonstrate that proposed stormwater system fully contains all new post-development peak rates and volumes of runoff for all storms analyzed including the 100-year storm. MassDEP Stormwater Standard 3: Recharge – Loss of annual recharge to groundwater shall be eliminated or minimized using 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 shall approximate the annual recharge from 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. Recharge to groundwater will be provided through the runoff volume infiltrated within the retention/recharge basin. The recharge volume provided exceeds the recharge requirement and consequently, satisfies Standard 3. Refer to the Section 4.3 of this report for supporting calculations. MassDEP Stormwater 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 Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report Handbook; and c.Pretreatment is provided in accordance with the Massachusetts Stormwater Handbook. The project proposes the use of deep sump hooded catch basins, oil/grit separators, a proprietary water quality unit, and a retention/recharge basin to remove the required post-construction load of TSS per the Massachusetts DEP Stormwater Management Standards. The TSS removal worksheets are located within Section 4.2 of this report. The Long-Term Pollution Prevention Plan is included in conjunction with the Operation and Maintenance Plan required by Standard 9 (refer to Section 2 of this report). MassDEP Stormwater 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, §§ 26-53 and the regulations promulgated there under at 314 CMR 3.00, 314 CMR 4.00 and 314 CMR 5.00. The project is not considered a LUHPL (Land Use with Higher Potential Pollutant Load). MassDEP Stormwater Standard 6: Critical Areas –Critical areas are Outstanding Resource Waters as designated in 314 CMR 4.00, Special Resource Waters as designated in 314 CMR 4.00, recharge areas for public water supplies as defined in 310 CMR 22.02 (Zone Is, Zone IIs, and Interim Wellhead Protection Areas for groundwater sources and Zone (A)s for surface water sources.) There will be no untreated stormwater discharges to a “Critical Area,” however, the project location falls within the Town of Yarmouth Aquifer Protection Overlay District. The stormwater management system has been designed to comply with the applicable requirements within the Aquifer Protection District. Overall, the project Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report provides the required TSS removal of 80% or higher. Refer to the attached TSS removal worksheets located in Section 4.2 of this report. MassDEP Stormwater Standard 7: Redevelopment Projects –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. This project is a mix of new and redevelopment under the Stormwater Management Standards. The project has been designed to meet and provide full compliance with the Stormwater Management Standards for new and existing impervious areas. MassDEP Stormwater Standard 8: Construction Period Pollution Prevention Plan and Erosion and Sedimentation Control – 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. A Construction Pollution Prevention Plan has been prepared for the project (see Section 2). Provisions to maintain runoff control devices have been assured through non-structural, structural, and construction management approaches. MassDEP Stormwater 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. A Long-Term Operation and Maintenance Plan has been prepared for the project (see Section 2). Provisions to maintain runoff control devices have been assured through non-structural, structural, and construction management approaches. MassDEP Stormwater Standard 10: Prohibition of Illicit Discharges – All illicit discharges to the stormwater management system are prohibited. The Operation and Maintenance plan required by Standard 9 includes measures to prevent illicit discharges (see Section 2). An Illicit Discharge Compliance Statement is included in Section 4.7. Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report 1.5.2 YARMOUTH STORMWATER MANAGEMENT PERFORMANCE STANDARDS 1)Low Impact Development (LID)– Low impact design strategies are implemented in into the site design including roof runoff infiltration, parking lot trees, and interior parking spaces. 2)Good Housekeeping Procedures – Good housekeeping procedures will be implemented at the site as described in the Operation and Maintenance Plan that is included with the application for Stormwater Management Permit. 3)Stormwater Management System Design Requirements – The stormwater management system design is consistent with the 2008 Massachusetts Stormwater Management Standards as documented above and the additional requirements of Section 2.05.(3) of the Yarmouth Stormwater Management Performance Standards. Post-development peak discharge rates will not exceed pre-development peak discharge rates for the 2, 10, 25, 50, and 100-year storms because all runoff, including the 50-year and 100-year runoff volumes are contained onsite without discharge. Structural pretreatment is provided to remove 44% TSS from runoff prior to discharge into the retention/recharge basin. Rainfall depths used in the calculation of runoff volumes and peak runoff rates are based on those contained in NOAA Atlas 14. 4)Stormwater Management Systems for New Developments – The proposed stormwater management system is designed to achieve an average pollutant removal equivalent to 90% of the annual load of Total Suspended Solids (TSS) and 60% of the average annual load of Total Phosphorous (TP) and 30% of the average annual load of Total Nitrogen (TN) by retaining the volume of runoff greater than 1.0 inch multiplied by the total post-construction impervious surface area on the new development site in accordance with Section 2.05(4)(b) of the Regulations. The proposed replacement retention/recharge basin has been designed to retain the 100-year runoff volume and so provides a volume equivalent to approximately 4 inches over the total post- construction impervious surface. Pretreatment is provided in accordance with Section 2.05(3)(b) of the Regulations. Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report 5)Stormwater Management Systems for Redevelopments – This project is not considered a redevelopment project and therefore this standard is not applicable. 6)BMP Performance Tracking – BMP performance is documented based on MassDEP design guidance and performance Standards. 7)Discharges to Impaired Water Bodies and Their Tributaries – The proposed stormwater management system does not discharge to an impaired waterbody and therefore this standard is not applicable. 1.6 BEST MANAGEMENT PRACTICES (BMPs) A treatment train consisting of deep sump catch basins, oil/grit separators, a Contech CDS proprietary water quality unit, and a retention/recharge basin are proposed to treat stormwater runoff on the site. See Section 4.2 for the Total Suspended Solids (TSS) Removal Calculations. A description of the devices incorporated is indicated below. 1.6.1 PROPOSED STRUCTURAL AND TREATMENT BMPs 1. DEEP SUMP HOODED CATCH BASINS Deep sump catch basins are modified versions of inlet structures installed to collect and convey stormwater on the site. The deep sumps, typically a 4-ft dimension below the outlet pipe invert, are most effective if placed “off-line” which means that they do not have inlet pipes. The catch basins contain traps or hoods on the outlet pipes and serve as pretreatment for other downstream BMPs. Deep sump catch basins will be installed throughout the site to remove trash, debris, sediment and a limited amount of oil and grease from stormwater runoff. To ensure maximum capacity and efficiency, the catch basins shall be inspected monthly and cleaned, in dry weather, when half of the sump capacity is filled or at a minimum quarterly or as required and at the end of construction. 2. OIL/GRIT SEPARATORS Oil/Grit separators are used to manage runoff from land uses with higher potential pollutant loads where there is a risk that the stormwater is contaminated with oil or grease. Oil/grit separators require regular maintenance with inspection monthly and cleaning at least twice per year. Cleaning included removal of accumulated oil and grease and sediment using a Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report vacuum truck. Polluted water or sediments removed should be disposed in accordance with all applicable local, state, and federal laws and regulations. 3. CDS- HYDRODYNAMIC SEPARATOR (WATER QUALITY UNIT) The CDS stormwater treatment units are a type of hydrodynamic separator. Hydrodynamic separators are a type of water quality manhole or catch basin inlet that relies on flow through the structures to promote settling and separation within the unit in order to remove sediments and other pollutants that are widely found in storm water. This technology will be used as a part of a treatment train consisting of other structural and non-structural approaches. Each device has been sized using the 1.0” equivalent water quality flow. These units serve as pretreatment for other downstream BMPs and a single unit will be installed to remove trash, debris, sediment and a limited amount of oil and grease from stormwater runoff. The hydrodynamic separators shall be inspected four times per year and cleaned, in dry weather, at least once per year or in accordance with the manufacturer’s recommendations. Cleaning will take place at the completion of construction and typically in early spring after sanding of roadways has ceased. Periodic inspections performed by the responsible party may dictate cleaning on a more frequent basis depending on the suspended solids loading. During construction accumulated sediment may need to be removed more frequently. Usually, a vacuum truck removes accumulated sediment and oil most efficiently. See maintenance documentation from the manufacturer for additional maintenance criteria. 4. RETENTION/RECHARGE BASIN A replacement recharge/retention basin is proposed to retain, recharge, and infiltrate storm runoff. The basin will provide peak flow reduction, stormwater runoff volume reduction, and TSS removal for various storm events. The proposed system drains down completely between storm events as required by the Massachusetts Stormwater Policy. Once the system goes online, inspections should occur after each storm event for the first few months to ensure proper stabilization, function, and to ensure that the outlets remain free of obstructions. Preventative maintenance shall be performed at least twice per year and after every major storm event (> 1.5” of rainfall) and shall include removal of accumulated sediment, inspection for unstable slopes, and erosion, to ensure proper operation of the system. Important items to check include differential settlement, cracking, breakout, clogging of outlets and vents, and root incursion. Water levels should be checked and recorded against rainfall amounts to verify that the drainage system is working properly Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report and draining within 72 hours. If they do not drain within 72 hours, corrective action should be taken. 1.7 HYDRAULICS AND PIPE SIZING The closed-conveyance storm drain collection system was analyzed using the Rational Method. Q = CiA, for estimating runoff where “C” is a coefficient dependent on land cover, “i” is storm intensity in in/hr based upon published I-D-F curves, and “A” is area in acres. “Q” is flow in cubic feet per second. The project site is subdivided by catch basin or inlets based upon drainage areas tributary to each. A “C” value for each area was assigned based upon overall character of land. “C” values ranged from 0.9 in paved/impervious conditions to 0.3 for grass and landscaped areas. IDF curves from Boston, Massachusetts is used to establish the rainfall rate for the 100-year event. Pipe hydraulic design was completed using Manning’s full flow capacity equation for circular pipe with an n- value of 0.013 Q = 1.49/n AR2/3 S1/2,where, n is coefficient depending on channel roughness, A is area of flow, R is the hydraulic radius, and S is the channel slope. 1.8 SUMMARY OF HYDROLOGY & STORMWATER CALCULATIONS The results of the pre and post-development hydrology calculations provided in Section 3 are summarized in the following tables. The table corresponds to the design points as indicated on the drainage area maps and hydrograph routing calculations. TABLE – 1 TOTAL RUNOFF PEAK FLOW RATE (CFS) DESIGN POINT 2/4 (DP-2/4) STORM SCS 24-HR EXISTING DP2 EXISTING DP4 PROPOSED DP2/4 2-YEAR 3.43 3.06 11.42 10-YEAR 6.47 6.32 21.83 25-YEAR 8.45 8.54 28.68 50-YEAR 9.97 10.28 33.96 100-YEAR 11.55 12.10 39.43 Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report TABLE – 2 TOTAL RUNOFF VOLUME – STAGE/STORAGE DESIGN POINT 4 (DP-2/4) STORM SCS 24-HR EX. MAX. ELEVATION, FT PROP. MAX ELEVATION, FT 2-YEAR 32.95 32.66 10-YEAR 34.86 34.50 25-YEAR 35.89 35.50 50-YEAR 36.61 36.20 100-YEAR 37.31 36.89 TABLE – 3 TOTAL RUNOFF PEAK FLOW RATE (CFS) DESIGN POINT 3 (DP-3) STORM SCS 24-HR EXISTING PROPOSED DIFFERENCE 2-YEAR <0.01 < 0.01 0.00 10-YEAR <0.01 < 0.01 0.00 25-YEAR <0.01 <0.01 0.00 50-YEAR 0.01 <0.01 -0.01 100-YEAR 0.03 0.01 -0.02 TABLE -4 TOTAL RUNOFF PEAK FLOW RATE (CFS) DESIGN POINT 5 (DP-5) STORM SCS 24-HR EXISTING PROPOSED DIFFERENCE 2-YEAR < 0.01 < 0.01 0.00 10-YEAR < 0.01 < 0.01 0.00 25-YEAR < 0.01 < 0.01 0.00 Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report STORM SCS 24-HR EXISTING PROPOSED DIFFERENCE 50-YEAR 0.01 0.01 0.00 100-YEAR 0.02 0.02 0.00 1.9 CONCLUSION In conclusion, the project incorporates a series of structural and nonstructural Best Management Practices (BMPs) that are designed to enhance stormwater runoff quality by providing the required TSS removal and control peak discharge rates and volumes onsite for all storms analyzed up to and including the 100-yr design storm. Although an increase in the peak rates of runoff is expected for Subcatchment 2S/4S, the proposed replacement retention/recharge basin will contain the expected runoff volume generated by the 100-year storm so that offsite flooding impact will be mitigated. Note that Table 2 indicates that the elevation of the water within the basin in the proposed case is slightly lower than in the existing, indicating less impact to the upstream conveyance system in the proposed condition. No increase in peak runoff is expected from Subcatchments 3 and 5. The proposed stormwater system has been designed to meet Massachusetts and Town of Yarmouth Stormwater Management Standards for TSS removal, recharge, and water quality treatment. The documentation provided in this report has been prepared to illustrate that stormwater runoff from the proposed project will be mitigated and that there will not be any adverse stormwater impacts to the surrounding area from the proposed project. 1.10 REFERENCES 1.Commonwealth of Massachusetts, Department of Environmental Protection, Stormwater Management Standards Handbook. Volumes 1-3 February 2008 (DEP Stormwater Management Policy 2008). 2.Commonwealth of Massachusetts, Department of Environmental Protection. 310 CMR 10.00: Massachusetts Wetlands Protection Act Regulations. 2008. 3.Commonwealth of Massachusetts, Department of Environmental Protection. 314 CMR 4.00: Massachusetts Surface Water Quality Standards. 2007. 4.Commonwealth of Massachusetts, Department of Environmental Protection. 314 CMR 9.00: Massachusetts Water Quality Regulations. 2008. Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report 5.United States Department of Agriculture, Natural Resources Conservation Services Urban Hydrology for Small Watersheds, Technical Release 55 (TR-55). June 1986. 6.United States Department of Agriculture, Natural Resources Conservation Services Project Formulation Hydrology Program System, Technical Release 20 (TR-20). Oct. 2004. 1.11 GENERAL CONSTRUCTION SEQUENCING The following section provides construction details and highlights the construction sequence and timing of earthmoving activities. The overall project will be broken down into the following phases: Establish Erosion and Sediment Controls around the project site Demolition (ex. structures, driveways, utilities) Building renovations Site clearing and grading, drainage, utility, and site installation Final utility connections, paving, and permanent stabilization A.Pre-construction Meeting An on-site meeting will be conducted by the Owner’s Representative prior to the start of construction activity. B.Installation of Erosion Controls Erosion and sedimentation controls (i.e. silt fence, filter sock, and inlet protection) will be installed at the limits of work and within the existing catch basins, as applicable. Tree protection will be installed around trees specified to remain within the limit of work. Structures to remain shall also be visibly flagged/protected. C.Installation of Construction Entrance A construction entrance will be installed in the location as shown on the Erosion Control Plan in accordance with the construction detail provided in the plan set. Existing pavement will be removed within the limits of the proposed construction entrance to accommodate the crushed stone entrance. D.Installation of Temporary Sediment Basins Temporary sediment basins will be installed as needed with vertical 12” perforated pipe wrapped with filter fabric and screen on top for overflow. Side slopes of the temporary sediment basins Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report shall be 3 foot horizontal to 1 foot vertical. Sediment to be removed when accumulation is within 6” of the outlet elevation. E.Demolition Utilities services, and pavement within the project area will be demolished in accordance with the Construction Plans. Those utilities effected by construction activities shall be coordinated with the utility purveyors and Dig Safe procedures taken prior to implementation of agreed upon connections/disconnections/abandonment of services. Materials that are to be removed from the site will be transported to an appropriate facility or will be disposed of elsewhere according to Federal, State, and Local guidelines. Inactive stockpiles or areas of granular material or topsoil shall be temporarily secured in order to control sediment laden runoff. F.Site Clearing and Rough Grading The site will be cleared and rough graded in accordance with the proposed grading as shown on the plans. If suitable topsoil is found, it will be removed and stockpiled within the project limits. Areas which have been cleared will be stabilized. G. Building Construction This phase of construction will involve alteration and renovation of the existing building including both interior and exterior improvements. All building waste is to be properly disposed of in dumpsters. While this phase commences, other site construction activities will continue. H. Installation of Drainage and Utilities Utility relocations and modifications, including electric are anticipated to occur in conjunction with the drainage work. Temporary sediment basins will be constructed at this time on an as- needed basis to collect stormwater runoff during construction. Stockpiles will be established in designated areas. All temporary/inactive stockpile areas will be encompassed by filter sock and silt fence or other approved erosion control devices to control sediment laden runoff as necessary and will be temporarily seeded, mulched or covered with plastic, as necessary. I.Fine Grading, Paving, Etc. The fine grading and shaping will commence along with the installation of curbing to prepare for paving operations. Areas outside of the parking surfaces will be shaped and prepped for loam, seed, or other landscape treatments. Concrete and asphalt paving operations will begin. After the asphalt binder course has been installed the finish top course will be applied. Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Stormwater Report J.Permanent / Final Site Stabilization The final phase of the project consists of landscaping and restoration and stabilization of all exposed surfaces. Final landscaping will be performed upon completion of earthwork and completion of all curbing and sidewalk construction. Disturbed areas will be landscaped, mulched or seeded in accordance with the landscape requirements. Permanent restoration and revegetation measures serve to control erosion and sedimentation by establishing a vegetative cover. In the event that weather conditions prevent final restoration, temporary erosion and sedimentation measures will be employed until the weather is suitable for final cleanup. A final inspection will ensure that the project site is cleared of all project debris and that erosion and sedimentation controls are functioning properly. Once the site has been stabilized, the entire stormwater management system will be inspected for sediment deposits and cleaned if necessary. Section 1.12 Figures Drawing Copyright © 2022 www.chacompanies.com 141 Longwater Drive - Suite 104 781.982.5400 Norwell, MA 02061 Drawing Copyright © 2022 www.chacompanies.com 141 Longwater Drive - Suite 104 781.982.5400 Norwell, MA 02061 Section 2.0 Long-Term Pollution Prevention and Operation and Maintenance Plan Construction Period Operation and Maintenance Plan Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 1 LONG-TERM STORMWATER POLLUTION PREVENTION AND OPERATION & MAINTENANCE PLAN TO COMPLY WITH STORMWATER STANDARDS 4, 6, & 9 APPLICABILITY This document identifies constituents of concern that have the potential to contaminate stormwater from the proposed Warehouse and Distribution Center Alteration project located at 225 White’s Path, Yarmouth, Massachusetts and provides a framework of Best Management Practices (BMPs) for handling stormwater runoff. It also outlines an inspection and maintenance program to ensure continued effectiveness of the proposed stormwater management system. The proposed BMP’s are shown on the plans prepared by CHA, 141 Longwater Drive, Suite 104, Norwell, Massachusetts. PROJECT OVERVIEW: The proposed project located on White’s Path includes alterations to the existing commercial building and incorporates associated site improvements including parking and utilities. The project will not increase the overall footprint of the building. The project has been designed to meet State and Local standards for TSS and pollutant removal through the use of BMPs. Runoff from impervious surfaces will be collected and treated by deep sump hooded catch basin, oil/grit separators, a CDS Water Quality Unit, and conveyed to a stormwater recharge/retention basin that will infiltrate the runoff into the surrounding soils. The existing rooftop runoff is collected and conveyed to an independent underground infiltrration system will not be altered by the Project. Appended to this document is a sample maintenance form and a chart describing the anticipated frequency of tasks. OWNER AND RESPONSIBLE PARTY: Owner: 225 White’s Path Units Two and Three, LLC 231 Willow Street Yarmouthport, MA 02675 Day-to-day Operation and Maintenance: Maintenance Company hired by Owner. ON-GOING MAINTENANCE CONTRACT The non-structural and structural approaches recommended below, as well as the required BMP maintenance, will be completed by an appropriate contractor. Adequate personnel with appropriate training and access to proper equipment will be available to complete the tasks. Future responsible parties must be notified of their responsibility to operate and maintain the system in perpetuity. LIVING DOCUMENT PROVISIONS Due to the difficulty of identifying all sources of potential stormwater contamination and Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 2 maintenance activities, this document should be updated as necessary to reflect new procedures, technologies or requirements. MAINTENANCE LOG The Responsible Party shall develop and maintain a log of inspections, maintenance, repairs, and disposal (including location of disposal) during the life of the project. Records will be maintained for at least 3 years and be made available to the Massachusetts Department of Environmental Protection or the Town of Yarmouth in accordance with the provisions of the Massachusetts Stormwater Handbook and Town of Yarmouth Stormwater Regulations. INSPECTIONS The Responsible Party shall allow the Yarmouth Conservation Commission to inspect each BMP to confirm that the Operations and Maintenance is being implemented. CERTIFICATION The Responsible Party shall submit an annual certification, in accordance with Section 2.07(1)(i) iv, to the Yarmotuh Conservation Commission. MINIMIZING EXPOSURE The Responsible Party shall minimize exposure of potential pollutant sources, including debris from coming into contact with precipitation and being picked up by stormwater and carried into drains and surface waters using the following steps: Storing all containerized materials in a protected, secure location away from drains and plainly labeled. Containing all activities that can generate sources of contaminants from reaching the receiving water or the stormwater management system. Securing any equipment or supplies so that they are not transported during storm events into receiving waters or stormwater management system. BEST MANAGEMENT PRACTICES (BMP) MAINTENANCE The proposed stormwater management system has been designed with appropriate BMPs aimed at reducing the pollutants discharge based upon the intended use of the proposed development. All BMPs require regular maintenance to function as intended. Some management measures have simple maintenance requirements; others are more involved. The Responsible Party must have all BMPs regularly inspected to ensure they are operating properly on an as-needed basis, including during runoff events exceeding 0.5 inches of rainfall. A description of the non-structural and structural approaches to be incorporated is indicated below. The following Best Management Practices are proposed to be incorporated into the stormwater management design to reduce source runoff and improve stormwater runoff discharge quality. The Responsible Party will regularly inspect all BMPs to ensure they are operating properly. If any deficiencies are identified during these inspections, action to resolve it will be initiated and documented on the maintenance log. Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 3 NON-STRUCTURAL BEST MANAGEMENT PRACTICES (BMPs) STREET/PARKING LOT SWEEPING This practice, considered by MassDEP to be a non-structural BMP, provides effective removal of Total Suspended Solids (TSS) in a comprehensive stormwater management program. A maintenance program of roadway/driveway sweeping with a High Efficiency Vacuum Sweeper or a Regenerative Air Sweeper to reduce sediment accumulation in the deep sump catch basins and subsurface systems shall be implemented based on the owner discretion. Sweeping can be conducted on a quarterly basis (primarily in the spring and fall) to keep low impact BMPs operating effectively. GRADING The impervious areas of the site shall be graded as gently as possible, generally not more than 6% slopes, to reduce runoff velocities. Steep slopes will be permanently vegetated to dissipate energy and reduce potential erosion. No constructed vegetated slopes shall exceed 3H:1V without providing additional reinforcement. Steep slopes may require soil reinforcement and additional vegetation. SNOW STORAGE AND DEICING Snow storage will be located adjacent to parking area as directed. In the event of a large snow event that exceeds snow storage on the site, snow will be removed and hauled off-site. In the interest of reducing the volume of dissolved salt that enters the watershed, the operator of the development will rely on sand alone where traction on snowy surfaces is the primary objective. However, parking areas, driveways, and sidewalks which require deicing for safety during winter months will typically be treated with calcium magnesium acetate or another alternative as approved by the Yarmouth Conservation Commission. FERTILIZER: Due to the project’s location within an environmentally sensitive area, any use of fertilizers will be limited to those as approved by the Yarmouth Conservation Commission. PESTICIDES/HERBICIDES: Due to the project’s location within an environmentally sensitive area, any use of pesticides/herbicides will be prohibited unless otherwise approved by the Yarmouth Conservation Commission. WASTE MANAGEMENT: Solid waste will be contained within dumpsters. Waste deposition in these receptacles will be consistent with state and local permits. The covers and doors of the dumpsters will be kept closed to limit rainwater/wildlife intrusion. Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 4 STRUCTURAL BEST MANAGEMENT PRACTICES: Prior to final completion and full occupancy of the development, it is recommended that a representative of the Contractor, Manufacturer, and/or Engineer either designing or building the facility for the Owner properly instruct the Responsible Party as to the maintenance practices required to responsibly maintain the effectiveness of the drainage system. These frequencies and requirements are recommendations to maintain minimum effectiveness in most typical environments. Ultimately, the Responsible Party will implement the procedures and frequencies as they see fit under their current plan and inspect the systems as needed to maintain minimum effectiveness as recommended by the manufacturer. The following maintenance of structural BMPs will be implemented: ROOF DRAIN GUTTERS, DOWNSPOUTS, AND SUBSURFACE INFILTRATION BASIN Roof drain gutters, downspouts, and subsurface infiltration basin should be inspected and cleaned twice a year, once in the fall after leaf drop and in the spring after snow melt. Cleaning will take place at the completion of construction and in early spring after snow melt. Any obstructions, sediment, and debris that could potentially cause clogging shall be removed within the roof drain gutter and downspout system as necessary. DEEP SUMP CATCH BASINS AND MANHOLE STRUCTURES Catch basins shall be cleaned, in dry weather, when half of the sump capacity is filled or at a minimum quarterly or as required through periodic inspection. Cleaning will take place at the completion of construction and in early spring after sanding of roadways has ceased or as needed depending on the frequency of major storm events (greater than 1-inch of rainfall). All manholes shall be inspected at least once annually. Any obstructions, sediment, and debris that could potentially cause clogging shall be removed within the conveyance system as necessary. Inverts, grates, and hoods shall be checked and replaced as necessary to maintain hydraulic effectiveness. OIL/GRIT SEPARATORS Oil/Grit separators are used to manage runoff from land uses with higher potential pollutant loads where there is a risk that the stormwater is contaminated with oil or grease. Oil/grit separators require regular maintenance with inspection monthly and cleaning at least twice per year. Cleaning included removal of accumulated oil and grease and sediment using a vacuum truck. Polluted water or sediments removed should be disposed in accordance with CDS- HYDRODYNAMIC SEPARATORS (WATER QUALITY UNITS) The CDS stormwater treatment units are a type of hydrodynamic separator. Hydrodynamic separators are a type of water quality manhole or catch basin inlet that relies on flow through the structures to promote settling and separation within the unit in order to remove sediments and other pollutants that are widely found in storm water. This technology will be used as a part of a treatment train consisting of other structural and non-structural approaches. Each device has been sized using the 1.0” equivalent water quality flow and will be reviewed per manufacturer’s recommendations and checked by the representative. Water quality inlets will Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 5 be installed throughout the site to remove trash, debris, sediment and a limited amount of oil and grease from stormwater runoff. The hydrodynamic separators shall be inspected four times per year and cleaned, in dry weather, at least once per year or in accordance with the manufacturer’s recommendations. Cleaning will take place at the completion of construction and typically in early spring after sanding of roadways has ceased. Periodic inspections performed by the responsible party may dictate cleaning on a more frequent basis depending on the suspended solids loading. During construction accumulated sediment may need to be removed more frequently. Usually, a vacuum truck removes accumulated sediment and oil most efficiently. See maintenance documentation from the manufacturer for additional maintenance criteria. Inverts, grates, and hoods shall be checked and replaced as necessary to maintain hydraulic effectiveness. RETENTION/RECHARGE BASIN A retention/recharge basin receives stormwater from the upstream drainage system and retains and infiltrates it into the surrounding soil. The basin shall be inspected on a semi- annual basis in the early spring and fall. Additional inspections shall be performed during the first few months after construction to ensure that adequate vegetation has been established. Regular maintenance shall include mowing, fertilizing, pruning, debris, trash and sediment removal, and weed/pest control. The basin buffer area, side slopes, and basin bottom shall be mowed at least twice per year. SPILL CONTROL: The development consists of a warehouse and distribution facility. It is recommended, that if there is no existing contingency plan to address the spillage/release of petroleum products and any hazardous material, one be developed and implemented. The recommendation includes that the Owner have all MassDEP emergency spill response information posted onsite at all times. It is also recommended an emergency spill response kit including absorbent pillows be stored on-site along with instructions for the kit, a copy of applicable regulations regarding spills, and a list of individuals to contact (local and state officials) in the event of a spill. Spills or leaks will be treated properly according to material type, volume of spillage, and location of the spill. Mitigation will include preventing further spillage, containing the spilled material in the smallest practical area, removing spilled material in a safe and environmentally friendly manner, and remediating any damage to the environment. LONG-TERM OPERATION AND MAINTENANCE BUDGET: Consistent with Standard 9 of the Massachusetts Department of Environmental Protection Stormwater Handbook (February 2008) the approximate cost of inspections and maintenance based on the abovementioned post-construction activities and frequencies is as follows: •Pavement Sweeping - $3,000 per year based on annual sweepings. •Deep Sump Catch Basins - inspection/cleaning - $1000 per year/per catch basin based on quarterly inspections and sediment removal of both single and double grate deep sump catch basins. •Oil/Grit Separator - inspection - $1000 per year based on semi-annual inspections. Cleaning/debris removal/maintenance - $1,000 per year for accumulated sediment and trash Warehouse & Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 6 removal. •Water Quality Unit – inspection - $1000 per year based on quarterly inspections. Cleaning/debris removal/maintenance - $1000 per year for accumulated sediment and trash removal. •Retention/Recharge Basin - inspection - $1,000 per year based on semi-annual inspections. Cleaning/debris removal - $1,000 per year for accumulated sediment and trash removal. Additional costs may be incurred if it is determined during routine inspections of the BMP's that further corrective actions are necessary. Executed as of this _____ day of ___________ PROPERTY OWNER: 225 White’s Path Units Two and Three, LLC _____________________________________ Signature Printed Name:___________________ Title:___________________ Date Authorized:___________________ LONG TERM STRUCTURAL BEST MANAGEMENT PRACTICE INSPECTION & MAINTENANCE MATRIX AFTER CONSTRUCTION Note: BMP's shall be visually inspected and repaired by a qualified party in accordance with the following chart. Note these are minimum inspection criteria/frequencies and should be adjusted throughout the project lifespan as required to maintain effectiveness. Refer to maintenance standards for drainage facilities and structural best management practices in the "Recommended Long-Term Stormwater Pollution Prevention Plan."Conventional & LID BestManagement PracticesRecommended MinimumInspection &Maintenance FrequencyErosion/ScouringTree Growth HazardsDifferentialSettlement/SeepageStructuralDamage/ObstructionsTrash & DebrisRemoval of AccumulatedSedimentSlope Integrity*Mow Vegetation/PoorVegetation CoverageRemove/Reset FilterFabric & Stone AsRequiredRemove & ReplaceHardwood mulch/mediaVac Truck Sediment &ContaminantsRemove/Reset Riprap asRequiredCatch Basins Annually X X X X X X Oil/Grit Separator Semi-Annually X X X X X Roof Drain Gutters, Downspouts, Infiltration Basin Semi-Annually X X X X X Contech CDS Water Quality Unit Semi-Annually / Per Manufacturer X X X X X Retention/Recharge Basin Semi-Annually X X X X X X X X X X Stormwater BMP Inspection and Maintenance Log Facility Name Address Begin Date End Date Date BMP ID#BMP Description Inspected by:Cause for Inspection Exceptions Noted Comments and Actions Taken Instructions: Record all inspections and maintenance for all treatment BMPs on this form. Use additional log sheets and/or attach extended comments or documentation as necessary. BMP ID# — Always use ID# from the Operation and Maintenance Manual or Approved Plans. Inspected by — Note all inspections and maintenance on this form, including the required independent annual inspection. Cause for inspection — Note if the inspection is routine, pre-rainy-season, post-storm, annual, or in response to a noted problem or complaint. Exceptions noted — Note any condition that requires correction or indicates a need for maintenance. Comments and actions taken — Describe any maintenance done and need for follow-up. Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 1 CONSTRUCTION PERIOD POLLUTION PREVENTION AND EROSION AND SEDIMENTATION CONTROL PLAN STORMWATER STANDARD 8 INTRODUCTION: This Construction Period Pollution Prevention Operation and Maintenance Plan has been created for the Warehouse and Distribution Center Alterations project located at 225 White’s Path in Yarmouth, MA. The goals of this CPOM (Construction Period O&M) are to detail the structural and non- structural practices selected to control erosion associated with surface stormwater discharges during construction and increase pollution attenuation after construction has been completed. Stormwater Best Management Practices (BMPs) have been incorporated into the design and will be implemented during construction to attenuate potential pollutants, dampen peak flow velocities, and prevent erosion. The format of this Plan follows the framework detailed as required by Standard 8 of the Stormwater Handbook. NARRATIVE: The Applicant, 225 White’s Path Units Two and Three, LLC, proposes to redevelop an existing warehouse and distribution center building in Yarmouth, MA. The site is comprised of a single large parcel, 17.7 acres in size. The building that occupies the site has an approximate footprint of 156,000 square-feet and will not be altered by the project. The site is bounded by White’s Path on the north, commercial developments on the east and west, and the Cape Cod Rail Trail on the south. The site is in the Business 3 zoning district and the Aquifer Protection and ROAD overlay districts. There are no wetland resource areas on or within 100 feet of the parcel. The site is not located within a habitat area designated by the Natural Heritage and Endangered Species Program (NHESP). The drainage systems on the site are comprised of closed-conveyance pipe systems which will collect and convey stormwater runoff from paved surfaces to an open retention/recharge basin. Treatment of the stormwater runoff will be via deep sump catch basins, oil/grit separators, and a CDS water quality unit prior to discharge to the retention/recharge basin. The retention/recharge basin provides additional treatment of the runoff prior to recharge into the surrounding soils. The retention/recharge basin is designed to fully contain the runoff volume expected from the 100-year storm. The stormwater system provides the required treatment for stormwater runoff from impervious areas as required by the 2008 Massachusetts Stormwater Handbook. Refer to the attached site plans for additional information. The project will continue to be serviced with potable water provided by the Town of Yarmouth and the wastewater treatment and disposal is via an existing onsite Title 5 septic system. Electricity is supplied by National Grid. Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 2 PARTIES RESPONSIBLE FOR COMPLIANCE Owner: Two Twenty Five White’s Path Units Two and Three, LLC 231 Willow Street Yarmouthport, MA 02675 Area of Control: Two Twenty Five White’s Path Units Two and Three, LLC has operational control over the construction plans and specifications for the project and has the ability to make modifications to the plans and specifications. Construction Manager or Site Supervisor: TO BE DETERMINED Area of Control: A construction manager with adequate knowledge and experience on projects of similar size and scope shall be employed to oversee all site construction. The contractor shall incorporate the appropriate techniques to control sediment and erosion pollution during construction in accordance with the Massachusetts Erosion and Sediment Control Guidelines for Urban and Suburban Areas and any conditions of approval from the local conservation commission. The design incorporates measures to control construction-related impacts including erosion, sedimentation and other pollutant sources during construction and land disturbance activities. The information contained herein and within the engineering drawings identifies construction period pollution prevention measures, responsible parties, erosion control measures (filter socks and silt fence, etc.), BMPs for collecting and treating runoff and groundwater during construction1, site stabilization measures (i.e. gravel, seed, pavement, etc.), an operations and maintenance plan and long-term pollution prevention plan contained herein. Care should be taken when constructing stormwater control structures. Light earth-moving equipment shall be used when operating over top of buried utilities or drain or chambers. GOOD HOUSEKEEPING PRACTICES DURING CONSTRUCTION The Construction Manager shall maintain good housekeeping practices by maintaining a clean and orderly facility to prevent potential pollution sources, including debris, from coming into contact with stormwater and degrading water quality. This includes establishing protocols to reduce the 1 Should the need for de-watering arise during construction at the site, groundwater will be pumped directly from the work area into geotextile filter bags, temporary settling basins, or portable fractionation tanks (depending on the nature and volume of water encountered) which will act as sediment traps during construction. Discharge points will be set outside of all resource areas and buffers monitored by qualified personnel (wetland scientist, licensed site professional, civil engineer, etc.) to ensure no impacts to resource areas and compliance with applicable Federal and State regulations. All discharges will be free from visible floating, suspended, and settleable solids that would impair the functions of the nearby drainage systems, wetlands, or downstream rivers. Refer to the details provided on the drawing set for additional information. Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 3 possibility of mishandling materials or equipment and training employees in good housekeeping techniques. Common areas where good housekeeping practices should be followed includes: material storage areas, vehicle and equipment maintenance areas, and loading areas. Good housekeeping practices must include a designated and secure location for garbage. A schedule for regular pickup and disposal of garbage and waste materials and routine inspections of containers for leaks and structural integrity shall be developed. Specific good housekeeping practices that will be implemented include routine removal of trash. items including scrap, metal, wood, plastic, miscellaneous trash, paper, glass, insulation, misc. building materials, and packaging. Additional practices include securing and covering any containers, supplies, or equipment that could become sources of stormwater pollution. MINIMIZING EXPOSURE DURING CONSTRUCTION The Responsible Party shall minimize exposure of potential pollutant sources, including debris from coming into contact with precipitation and being picked up by stormwater and carried into drains and surface waters using the following steps: Storing all containerized materials in a protected, secure location away from drains and plainly labeled. Containing all activities that can generate sources of contaminants from reaching the receiving water or the stormwater management system. Securing any equipment or supplies so that they are not transported during storm events into receiving waters or stormwater management system. BEST MANAGEMENT PRACTICES (BMP) MAINTENANCE The proposed stormwater management system has been designed with appropriate BMPs aimed at reducing the pollutants discharge based upon the intended use of the proposed development. All BMPs require regular maintenance to function as intended. Some management measures have simple maintenance requirements; others are more involved. The Construction Manager must have all BMPs regularly inspected weekly or after events exceeding 0.25 inches of rainfall to ensure the BMPs are operating properly. The Construction Manager shall develop and maintain a log of inspections, maintenance, repairs, and disposal (including location of disposal) during the life of the project. Records will be maintained for at least 3 years and be made available to the Massachusetts Department of Environmental Protection or the Town of Yarmouth in accordance with the provisions of the Massachusetts Stormwater Handbook. A description of the non-structural and structural approaches to be incorporated is indicated below. The following Best Management Practices are proposed to be incorporated into the stormwater management design to reduce source runoff and improve stormwater runoff discharge quality. The Responsible Party will regularly inspect all BMPs to ensure they are operating properly. If any deficiencies are identified during these inspections, action to resolve it will be initiated and documented on the maintenance log. Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 4 EROSION AND SEDIMENT CONTROLS: Erosion and sedimentation (ESC) measures will be installed as indicated on the site plans prior to the commencement of any construction activities and will be maintained throughout construction until the site is stabilized. ESC controls, in the form of 12-inch compost filter socks, temporary soil and stockpile areas, temporary sediment basins and drain inlet protection will be installed in accordance with project plans and details, as well as any other current State, and Local requirements. ESC measures will be incorporated into the project as needed by the contractor to control runoff and prevent impact to areas which are to remain undisturbed. ESC measures will be maintained and/or replaced as inspection deems necessary and or as directed by the Engineer, Architect, or Environmental Inspector. Sediment accumulations along ESC measures to a depth of 6-inches or more shall be removed and re-distributed to an area in manner that does not contribute to additional sediment migration. Contractors who disturb ESC measures will be required to repair/replace them and should inform the engineer or environmental inspector of deficiencies with ESC measures observed in the field. See Site Plans for locations of sediment controls. PERIMETER CONTROLS Perimeter sediment and stormwater controls consist of silt fence or compost filter socks which must be installed prior to commencement of earth disturbing activities at the site. Perimeter controls must be installed along the contour in the flattest area possible at a distance from the toe of slope; ends shall be placed up slope from the rest of the control. Perimeter controls must also be used around soil stockpiles as a sediment control measure. Perimeter measures will be maintained and/or replaced as inspection deems necessary and or as directed by the Engineer, Architect, or Environmental Inspector. Sediment accumulations along the perimeter measures to a depth of 6-inches or more shall be removed and re-distributed to an area in manner that does not contribute to additional sediment migration. Contractors who disturb ESC measures will be required to repair/replace them and should inform the engineer or environmental inspector of deficiencies with ESC measures observed in the field. SEDIMENT TRACK OUT Construction vehicles are anticipated to utilize the designated access drives, and construction entrances will be established at various points of entry into the construction zone. Construction entrance locations may be relocated as needed during different phases of the construction. Property entrance/exit locations will be maintained in a condition that will prevent tracking or flowing of sediment onto public roadways. The construction entrances will be inspected daily by the Site Supervisor. Fines imposed for tracking sediment onto public roads will be paid by the culpable Contractor. All materials spilled, tracked or otherwise transported onto public road rights-of-way will be immediately removed. Remove the track-out by sweeping, shoveling, or vacuuming these surfaces, or by using other similarly effective means of sediment removal. It is prohibited from hosing or Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 5 sweeping tracked-out sediment into any stormwater conveyance, storm drain inlet, or water of the U.S. STREET SWEEPING During the construction period, streets will be swept on an as-needed basis after all significant earth moving activities to remove pollutants and sediments that have accumulated. STOCKPILED SEDIMENT OR SOIL All inactive/temporary soil stockpiles will be protected with erosion controls and temporarily seeded, mulched or covered with plastic if not reused within 14 days. Long-term stockpiles may be compacted and hydro-seeded/mulched prior to the onset of wet weather. Temporary soil stockpiles shall be located within the active construction work area and be surrounded by an approved siltation barrier. Any exposed soils/disturbed areas where construction activity ceases for 14 or more calendar days will be temporarily stabilized with seed, mulch or a bonded-fiber mix or other approved erosion control material unless the area is covered with snow or unless work in the area is expected to resume within 21 days. This will be done on all slopes as well as exposed flat surfaces as deemed necessary. Straw material will be applied uniformly across disturbed areas to minimize erosion. Routine inspection and maintenance of stabilization practices will reduce soil erosion and minimize project runoff. For any stockpiled or land clearing debris composed, in whole or in part, of sediment or soil, the following measures must be followed: Locate the piles outside of any natural buffers established and physically separated from other stormwater controls implemented and as noted on the Plans; •Protect from contact with stormwater (including run-on) using a temporary perimeter sediment barrier; •Provide cover or appropriate temporary stabilization to avoid direct contact with precipitation or to minimize sediment discharge; •Do not hose down or sweep soil or sediment accumulated on pavement or other impervious surfaces into any stormwater conveyance (unless connected to a sediment basin, sediment trap, or similarly effective control), storm drain inlet, or surface water; and •Unless infeasible, contain and securely protect from wind. MINIMIZE DUST Dust control is important for controlling air quality on and off site during various phases of construction. Dust control will be provided on an as-needed basic during construction. Sprinkle irrigation using tanker trucks is effective to control dust from gravel/dirt haul roads and during earth- moving/grading phases of site preparation. On exposed soils where vehicular traffic is not expected and/or completed, vegetative cover and/or mulching can be used to stabilize soils. Stone graded out Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 6 over exposed areas where vegetation cannot be established can be effective along high traffic areas. Dust shall be monitored regularly onsite and treated as necessary. The following dust suppression methods may be used at the project: •Watering/Irrigation: Sprinkling the ground surface with water until it is moist. •Soil Stabilization: Vegetative cover, mulch, riprap or any method that covers the soil surface reduces the potential for soil particles to become airborne. •Wind Breaks: Wind breaks are barriers (either natural or constructed) that reduce wind velocity across exposed soil surfaces and reduces the potential for soil particles become airborne. Wind breaks can be trees or shrubs left in place during site clearing or constructed barriers such as a wind fence. If additional dust control measures are required, the situation will be assessed and addressed. TOPSOIL Where disturbance to native topsoil will occur at the site, unless infeasible, it must be preserved and reused. Existing and new vegetation will be maintained to the maximum extent practicable to prevent the contamination of storm water with sediment. Vegetated areas beginning to show signs of erosion or soil transport will be mulched or covered with jute netting or a comparable erosion control fabric to filter stormwater runoff prior to conveyance into the stormwater drainage system. SOIL COMPACTION In areas where final vegetative stabilization will occur or where infiltration practices (post development stormwater management system) and septic system will be installed either of the following measures must be followed by the Contractor: •Restrict vehicle and equipment use and stockpile of materials in these locations to avoid soil compaction •Prior to seeding or planting areas of exposed soil that have been compacted, use techniques that condition the soils to support vegetative growth, if necessary. STORM DRAIN INLETS Catch basins and area drains associated with the existing and/or proposed stormwater management system located within the project limits and the adjacent Right-of-Ways may collect and convey sediment and sediment-laden stormwater runoff. Therefore, all catch basins and area drains, existing and proposed, within construction zones, will be protected with silt sacks during construction and until final site stabilization is complete. SEDIMENT BASINS The removal and disposal of collected water from construction areas is a potential source of sediment and can lead to erosion during construction activities. Temporary sedimentation basins shall be constructed according to the site plans and EPA regulations. The temporary sedimentation Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 7 basins shall be monitored daily. Stormwater shall be directed towards the existing pipe conveyance system to help prevent overflow from leaving the construction work area. Temporary sediment basins/traps are instrumental in controlling sediment-laden stormwater runoff during initial phases of construction involving earthmoving activities before permanent stormwater management systems are in place. Sediment basins and traps will be constructed in accordance with Environmental Protection Agency (EPA) guidelines (See Project Plans – Appendix A). Sediment traps should have a minimum volume, based on 0.5-inch of storage for each acre of drainage area. Temporary sedimentation basins/traps shall be monitored daily. Stormwater shall be directed towards the existing conveyance system to help prevent overflow from leaving the construction work area. ROOF DRAIN GUTTERS AND DOWNSPOUTS Roof drain gutters and downspouts should be inspected once during construction and at the completion of construction. Cleaning will take place at the completion of construction and if applicable, in early spring after snow melt. Any obstructions, sediment, and debris that could potentially cause clogging shall be removed within the roof drain gutter and downspout system as necessary. DEEP SUMP CATCH BASINS AND MANHOLE STRUCTURES Catch basins and catch basin filter sacks shall be cleaned, in dry weather, when half of the sump capacity is filled or as required through inspection per the Inspection and Maintenance schedule (see section below). Cleaning will take place at the completion of construction or as needed depending on the frequency of major storm events (greater than 1-inch of rainfall). All manholes shall be inspected per the inspection and maintenance schedule (see section below) during construction and cleaned upon the completion of construction. Any obstructions, sediment, and debris that could potentially cause clogging shall be removed within the conveyance system as necessary. Inverts, grates, and hoods shall be checked and replaced as to maintain hydraulic effectiveness. OIL/GRIT SEPARATORS Oil/grit separators are used to manage runoff from land uses with higher potential pollutant loads where there is a risk that the stormwater is contaminated with oil or grease. Oil/grit separators require regular maintenance with inspection per the inspection and maintenance schedule (see section below) during construction. Cleaning will take place at the completion of construction. Cleaning includes removal of accumulated oil and grease and sediment using a vacuum truck. Polluted water or sediments removed should be disposed in accordance with all applicable local, state, and federal laws and regulations. CDS WATER QUALITY UNIT The CDS stormwater quality units are a type of hydrodynamic separator. Hydrodynamic separators are a type of water quality manhole or catch basin inlet that relies on flow through the structures to promote settling and separation within the unit in order to remove sediments and other pollutants that are widely found in storm water. The hydrodynamic separators shall be inspected four times per year and cleaned, in dry weather, at least once per year or in accordance with the manufacturer’s Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 8 recommendations. Cleaning will take place at the completion of construction and typically in early spring after sanding of paved surfaces has ceased. Periodic inspections performed by the responsible party may dictate cleaning on a more frequent basis depending on the suspended solids loading. During construction accumulated sediment may need to be removed more frequently. Usually, a vacuum truck removes accumulated sediment and oil most efficiently. See maintenance documentation from the manufacturer for additional maintenance criteria. Inverts, grates, and hoods shall be checked and replaced as necessary to maintain hydraulic effectiveness. RETENTION/RECHARGE BASIN A retention/recharge basin receives stormwater from the upstream drainage system and retains and infiltrates it into the surrounding soil. The basin shall be inspected on a semi-annual basis in the early spring and fall. Additional inspections shall be performed during the first few months after construction to ensure that adequate vegetation has been established. Regular maintenance shall include mowing, fertilizing, pruning, debris, trash and sediment removal, and weed/pest control. The basin buffer area, side slopes, and basin bottom shall be mowed at least twice per year. INSPECTION AND MAINTENANCE SCHEDULE At a minimum, the Contractor must conduct a site inspection at least once every 7 calendar days. OR Once every 14 calendar days and within 24 hours of the occurrence of a storm event of 0.5 inches or greater. To determine if a storm event of 0.5 inches or greater has occurred on the site, either keep a properly maintained rain gauge on the site or obtain the storm event information from a weather station that is representative of your location. VEGETATIVE PLANNING The Contractor must immediately initiate soil stabilization measures whenever earth-disturbing activities have permanently or temporarily ceased on any portion of the site. Earth-disturbing activities have temporarily or permanently ceased when clearing, grading and excavating within any area of the site that will not include permanent structures, will not resume for a period of 14 or more calendar days, but will resume in the future. Deadline to complete stabilization. As soon as practicable, but no later than 14 calendar days after the initiation of soil stabilization measures the following must be completed: •For vegetative stabilization, all activities necessary to initially seed or plant the area to be stabilized; and/or •For non-vegetative stabilization, the installation or application of all such non-vegetative measures. Seed shall be sown from April 1 to June 15, or from August 15 to September 30 unless otherwise approved by the Engineer. Deciduous planting season is April 1 to May 20 and October 1 to November 15th unless otherwise approved by the Engineer. Evergreen planting season is April 1 to May 20 unless otherwise approved by the Engineer. Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 9 SPILL CONTROL: The development consists of a warehouse/distribution center. It is recommended that if there is no existing contingency plan to address the spillage/release of petroleum products and any hazardous material be implemented for the development the one be fully developed. The Contractor shall have the MassDEP emergency spill response information posted onsite at all times. It is also recommended an emergency spill response kit including absorbent pillows be stored on-site along with instructions for the kit, a copy of applicable regulations regarding spills, and a list of individuals to contact (local and state officials) in the event of a spill. Spills or leaks will be treated properly according to material type, volume of spillage and location of spill. Mitigation will include preventing further spillage, containing the spilled material in the smallest practical area, removing spilled material in a safe and environmentally friendly manner, and remediating any damage to the environment. CONSTRUCTION SEQUENCING: The following section provides construction details and highlights the construction sequence and timing of earthmoving activities. The overall project will be broken down into the following phases: •Establish Erosion and Sediment Controls around the project site •Demolition (existing structures, driveways, utilities) •Building alterations •Site clearing and grading, drainage, utility, and site installation •Final utility connections, paving, and permanent stabilization A.Pre-construction Meeting An on-site meeting will be conducted by the Owner’s Representative prior to the start of construction activity. B.Installation of Erosion Controls Erosion and sedimentation controls (i.e. silt fence, filter sock, and inlet protection) will be installed at the limits of work and within the existing catch basins, as applicable. Tree protection will be installed around trees specified to remain within the limit of work. Structures to remain shall also be visibly flagged/protected. C.Installation of Construction Entrance A construction entrance will be installed in the location as shown on the Erosion Control Plan in accordance with the construction detail provided in the plan set. Existing pavement will be removed within the limits of the proposed construction entrance to accommodate the crushed stone entrance. D.Installation of Temporary Sediment Basins Temporary sediment basins will be installed as shown on the plans with vertical 12” perforated pipe wrapped with filter fabric and screen on top for overflow. Side slopes of the temporary sediment basins shall be 3 foot horizontal to 1 foot vertical. Sediment to be removed when accumulation is within 6” of the outlet elevation. Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 10 E.Demolition Utility services, and pavement within the project area will be demolished in accordance with the Construction Plans. Those utilities effected by construction activities shall be coordinated with the utility purveyors and Dig Safe procedures taken prior to implementation of agreed upon connections/disconnections/abandonment of services. Materials that are to be removed from the site will be transported to an appropriate facility or will be disposed of elsewhere according to Federal, State, and Local guidelines. Inactive stockpiles or areas of granular material or topsoil shall be temporarily secured in order to control sediment laden runoff. F.Site Clearing and Rough Grading The site will be cleared and rough graded in accordance with the proposed grading as shown on the plans. If suitable topsoil is found, it will be removed and stockpiled within the project limits. Areas which have been cleared will be stabilized. G.Building Construction This phase of construction will involve the alteration and renovation of the building including both interior and exterior improvements. All building waste is to be properly disposed of in dumpsters. While this phase commences, other site construction activities will be taking place. H.Installation of Drainage and Utilities Utility relocations and modifications, including electric, are anticipated to occur in conjunction with the drainage work. Temporary sediment basins will be constructed at this time on an as-needed basis to collect stormwater runoff during construction. Stockpiles will be established in designated areas as shown on project plans. All temporary/inactive stockpile areas will be encompassed by filter sock and silt fence or other approved erosion control devices to control sediment laden runoff as necessary and will be temporarily seeded, mulched or covered with plastic, as necessary. I.Fine Grading, Paving, Etc. The fine grading and shaping will commence along with the installation of curbing to prepare for paving operations. Areas outside of the parking lot will be shaped and prepped for loam, seed, or other treatments. Concrete and asphalt paving operations will begin. After the asphalt binder course has been installed the finish top course will be applied. J.Permanent / Final Site Stabilization The final phase of the project consists of landscaping and restoration and stabilization of all exposed surfaces. Final landscaping will be performed upon completion of earthwork and completion of all curbing and sidewalk construction. Disturbed areas will be landscaped, mulched or seeded in accordance with the landscape requirements. Permanent restoration and revegetation measures serve to control erosion and sedimentation by establishing a vegetative cover. In the event that weather conditions prevent final restoration, temporary erosion and sedimentation measures will be employed until the weather is suitable for final cleanup. A final inspection will ensure that the project site is cleared of all project debris and that erosion and sedimentation controls are functioning properly. Once the site has been Warehouse and Distribution Center Alterations 225 White’s Path, Yarmouth, MA CHA Project No. 072846 Page 11 stabilized, newly installed catch basins and the subsurface infiltration and detention systems will be inspected for sediment deposits and cleaned if necessary. Section 3.0 Hydrology and Hydraulic Modeling Section 3.1 HydroCAD Site Hydrology Calculations Section 3.1.1 Pre-Developed Stormwater Report Calculations 1S 1S 2S 2S 3S 3S 4S 4S 5S 5S 6S 6S 7S 7S 2P 4P Routing Diagram for 225 White's Path S Yarmouth Existing Hydrology Prepared by CHA Companies, Inc., Printed 6/15/2022 HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link 225 White's Path - Predevelopment Hydrology 225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 2HydroCAD® 10.10-6a s/n 01012 © 2020 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 3.35 2 2 10-year Type III 24-hr Default 24.00 1 4.87 2 3 25-year Type III 24-hr Default 24.00 1 5.82 2 4 50-year Type III 24-hr Default 24.00 1 6.54 2 5 100-year Type III 24-hr Default 24.00 1 7.28 2 225 White's Path - Predevelopment Hydrology 225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 3HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.235 49 50-75% Grass cover, Fair, HSG A (4S) 2.182 69 50-75% Grass cover, Fair, HSG B (1S, 2S, 7S) 0.207 85 Gravel roads, HSG B (7S) 0.016 96 Gravel surface, HSG B (1S) 2.413 98 Paved parking, HSG A (4S) 0.997 98 Paved parking, HSG B (1S, 2S, 7S) 0.013 98 Roofs, HSG A (4S) 3.579 98 Roofs, HSG B (6S) 0.353 98 Water surface (2S, 4S) 2.631 30 Woods, Good, HSG A (3S, 4S, 5S) 5.117 55 Woods, Good, HSG B (1S, 2S, 7S) 17.743 71 TOTAL AREA 225 White's Path - Predevelopment Hydrology 225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 4HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 5.292 HSG A 3S, 4S, 5S 12.099 HSG B 1S, 2S, 6S, 7S 0.000 HSG C 0.000 HSG D 0.353 Other 2S, 4S 17.743 TOTAL AREA 225 White's Path - Predevelopment Hydrology 225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 5HydroCAD® 10.10-6a s/n 01012 © 2020 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 0.235 2.182 0.000 0.000 0.000 2.416 50-75% Grass cover, Fair 1S, 2S, 4S, 7S 0.000 0.207 0.000 0.000 0.000 0.207 Gravel roads 7S 0.000 0.016 0.000 0.000 0.000 0.016 Gravel surface 1S 2.413 0.997 0.000 0.000 0.000 3.410 Paved parking 1S, 2S, 4S, 7S 0.013 3.579 0.000 0.000 0.000 3.592 Roofs 4S, 6S 0.000 0.000 0.000 0.000 0.353 0.353 Water surface 2S, 4S 2.631 5.117 0.000 0.000 0.000 7.748 Woods, Good 1S, 2S, 3S, 4S, 5S, 7S 5.292 12.099 0.000 0.000 0.353 17.743 TOTAL AREA 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 6HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=19,853 sf 0.15% Impervious Runoff Depth=0.43"Subcatchment 1S: 1S Flow Length=375' Tc=12.8 min CN=59 Runoff=0.11 cfs 0.016 af Runoff Area=110,819 sf 43.21% Impervious Runoff Depth=1.45"Subcatchment 2S: 2S Flow Length=481' Tc=12.7 min CN=79 Runoff=3.43 cfs 0.307 af Runoff Area=30,409 sf 0.00% Impervious Runoff Depth=0.00"Subcatchment 3S: 3S Flow Length=160' Tc=16.7 min CN=30 Runoff=0.00 cfs 0.000 af Runoff Area=182,876 sf 62.92% Impervious Runoff Depth=1.14"Subcatchment 4S: 4S Flow Length=681' Tc=29.1 min CN=74 Runoff=3.06 cfs 0.398 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.00"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.00 cfs 0.000 af Runoff Area=155,921 sf 100.00% Impervious Runoff Depth=3.12"Subcatchment 6S: 6S Tc=5.0 min CN=98 Runoff=12.07 cfs 0.930 af Runoff Area=246,382 sf 0.60% Impervious Runoff Depth=0.43"Subcatchment 7S: 7S Flow Length=839' Tc=10.6 min CN=59 Runoff=1.41 cfs 0.203 af Peak Elev=37.07' Storage=4,023 cf Inflow=3.43 cfs 0.307 afPond 2P: Outflow=0.86 cfs 0.307 af Peak Elev=32.95' Storage=6,184 cf Inflow=3.06 cfs 0.398 afPond 4P: Outflow=0.69 cfs 0.398 af Total Runoff Area = 17.743 ac Runoff Volume = 1.855 af Average Runoff Depth = 1.25" 58.55% Pervious = 10.388 ac 41.45% Impervious = 7.355 ac 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 7HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: 1S Runoff =0.11 cfs @ 12.27 hrs, Volume=0.016 af, Depth= 0.43" Routed to nonexistent node DP1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 29 98 Paved parking, HSG B 688 96 Gravel surface, HSG B 15,352 55 Woods, Good, HSG B 3,784 69 50-75% Grass cover, Fair, HSG B 19,853 59 Weighted Average 19,824 99.85% Pervious Area 29 0.15% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.1 42 0.0780 0.12 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.7 8 0.0827 0.19 Sheet Flow, B-C Grass: Short n= 0.150 P2= 3.35" 6.0 325 0.0081 0.90 Shallow Concentrated Flow, C-D Nearly Bare & Untilled Kv= 10.0 fps 12.8 375 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 8HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 1S: 1S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.12 0.115 0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=19,853 sf Runoff Volume=0.016 af Runoff Depth=0.43" Flow Length=375' Tc=12.8 min CN=59 0.11 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 9HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S Runoff =3.43 cfs @ 12.18 hrs, Volume=0.307 af, Depth= 1.45" Routed to Pond 2P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 41,929 98 Paved parking, HSG B 19,624 55 Woods, Good, HSG B 43,305 69 50-75% Grass cover, Fair, HSG B *5,961 98 Water surface 110,819 79 Weighted Average 62,929 56.79% Pervious Area 47,890 43.21% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 7.8 50 0.0594 0.11 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 3.3 123 0.0077 0.61 Shallow Concentrated Flow, B-C Short Grass Pasture Kv= 7.0 fps 0.8 106 0.0132 2.33 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 21 0.0191 6.79 5.33 Pipe Channel, D-E 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 51 0.0039 3.07 2.41 Pipe Channel, E-F 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0178 6.56 5.15 Pipe Channel, F-G 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 68 0.0177 6.04 4.74 Pipe Channel, G-H 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 12.7 481 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 10HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)3 2 1 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=110,819 sf Runoff Volume=0.307 af Runoff Depth=1.45" Flow Length=481' Tc=12.7 min CN=79 3.43 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 11HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Depth= 0.00" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 30,409 30 Woods, Good, HSG A 30,409 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.4 50 0.0108 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 1.3 110 0.0080 1.44 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.7 160 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=30,409 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=160' Tc=16.7 min CN=30 0.00 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 12HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: 4S Runoff =3.06 cfs @ 12.45 hrs, Volume=0.398 af, Depth= 1.14" Routed to Pond 4P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 546 98 Roofs, HSG A 105,115 98 Paved parking, HSG A 57,593 30 Woods, Good, HSG A 10,223 49 50-75% Grass cover, Fair, HSG A *9,399 98 Water surface 182,876 74 Weighted Average 67,816 37.08% Pervious Area 115,060 62.92% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 19.8 50 0.0058 0.04 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 7.9 207 0.0076 0.44 Shallow Concentrated Flow, B-C Woodland Kv= 5.0 fps 0.7 124 0.0189 2.79 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 53 0.0094 6.24 11.03 Pipe Channel, D-E 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.2 58 0.0052 4.64 8.21 Pipe Channel, E-F 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.4 189 0.0090 7.40 23.25 Pipe Channel, F-G 24.0" Round Area= 3.1 sf Perim= 6.3' r= 0.50' n= 0.012 Corrugated PP, smooth interior 29.1 681 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 13HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 4S: 4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)3 2 1 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=182,876 sf Runoff Volume=0.398 af Runoff Depth=1.14" Flow Length=681' Tc=29.1 min CN=74 3.06 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 14HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Depth= 0.00" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=26,613 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=73' Tc=13.6 min CN=30 0.00 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 15HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 6S: 6S Runoff =12.07 cfs @ 12.07 hrs, Volume=0.930 af, Depth= 3.12" Routed to nonexistent node DP6 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 155,921 98 Roofs, HSG B 155,921 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Subcatchment 6S: 6S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=155,921 sf Runoff Volume=0.930 af Runoff Depth=3.12" Tc=5.0 min CN=98 12.07 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 16HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 7S: 7S Runoff =1.41 cfs @ 12.21 hrs, Volume=0.203 af, Depth= 0.43" Routed to nonexistent node DP7 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 1,475 98 Paved parking, HSG B 9,035 85 Gravel roads, HSG B 187,932 55 Woods, Good, HSG B 47,940 69 50-75% Grass cover, Fair, HSG B 246,382 59 Weighted Average 244,907 99.40% Pervious Area 1,475 0.60% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 1.7 50 0.0513 0.50 Sheet Flow, A-B n= 0.054 P2= 3.35" 8.9 789 0.0084 1.48 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 10.6 839 Total Subcatchment 7S: 7S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=246,382 sf Runoff Volume=0.203 af Runoff Depth=0.43" Flow Length=839' Tc=10.6 min CN=59 1.41 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 17HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2P: Inflow Area =2.544 ac, 43.21% Impervious, Inflow Depth = 1.45" for 2-year event Inflow =3.43 cfs @ 12.18 hrs, Volume=0.307 af Outflow =0.86 cfs @ 12.68 hrs, Volume=0.307 af, Atten= 75%, Lag= 29.8 min Discarded =0.86 cfs @ 12.68 hrs, Volume=0.307 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 37.07' @ 12.68 hrs Surf.Area= 4,497 sf Storage= 4,023 cf Plug-Flow detention time= 41.0 min calculated for 0.307 af (100% of inflow) Center-of-Mass det. time= 41.0 min ( 890.7 - 849.8 ) Volume Invert Avail.Storage Storage Description #1 35.50'24,948 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 35.50 0 0.0 0 0 0 36.00 2,356 262.6 393 393 5,488 37.00 4,397 313.8 3,324 3,717 7,854 38.00 5,961 348.7 5,159 8,876 9,724 39.00 7,857 409.9 6,887 15,763 13,437 40.00 10,581 504.9 9,185 24,948 20,368 Device Routing Invert Outlet Devices #1 Discarded 35.50'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.86 cfs @ 12.68 hrs HW=37.07' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.86 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 18HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)3 2 1 0 Inflow Area=2.544 ac Peak Elev=37.07' Storage=4,023 cf 3.43 cfs 0.86 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 19HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 4P: Inflow Area =4.198 ac, 62.92% Impervious, Inflow Depth = 1.14" for 2-year event Inflow =3.06 cfs @ 12.45 hrs, Volume=0.398 af Outflow =0.69 cfs @ 13.39 hrs, Volume=0.398 af, Atten= 77%, Lag= 56.7 min Discarded =0.69 cfs @ 13.39 hrs, Volume=0.398 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 32.95' @ 13.39 hrs Surf.Area= 3,612 sf Storage= 6,184 cf Plug-Flow detention time= 99.1 min calculated for 0.398 af (100% of inflow) Center-of-Mass det. time= 99.1 min ( 979.7 - 880.6 ) Volume Invert Avail.Storage Storage Description #1 29.90'60,540 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.90 0 0.0 0 0 0 30.00 268 132.9 9 9 1,406 31.00 1,810 321.7 925 934 8,239 32.00 2,713 338.7 2,246 3,180 9,192 33.00 3,659 355.5 3,174 6,354 10,183 34.00 4,643 372.5 4,141 10,496 11,233 35.00 5,693 391.6 5,159 15,655 12,455 36.00 6,820 410.6 6,248 21,903 13,733 37.00 8,030 430.1 7,417 29,319 15,103 38.00 9,399 460.9 8,706 38,025 17,332 39.00 11,092 498.6 10,234 48,259 20,250 40.00 13,510 520.7 12,281 60,540 22,114 Device Routing Invert Outlet Devices #1 Discarded 29.90'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.69 cfs @ 13.39 hrs HW=32.95' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.69 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 20HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 4P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)3 2 1 0 Inflow Area=4.198 ac Peak Elev=32.95' Storage=6,184 cf 3.06 cfs 0.69 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 21HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=19,853 sf 0.15% Impervious Runoff Depth=1.16"Subcatchment 1S: 1S Flow Length=375' Tc=12.8 min CN=59 Runoff=0.43 cfs 0.044 af Runoff Area=110,819 sf 43.21% Impervious Runoff Depth=2.69"Subcatchment 2S: 2S Flow Length=481' Tc=12.7 min CN=79 Runoff=6.47 cfs 0.570 af Runoff Area=30,409 sf 0.00% Impervious Runoff Depth=0.00"Subcatchment 3S: 3S Flow Length=160' Tc=16.7 min CN=30 Runoff=0.00 cfs 0.000 af Runoff Area=182,876 sf 62.92% Impervious Runoff Depth=2.26"Subcatchment 4S: 4S Flow Length=681' Tc=29.1 min CN=74 Runoff=6.32 cfs 0.791 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.00"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.00 cfs 0.000 af Runoff Area=155,921 sf 100.00% Impervious Runoff Depth=4.63"Subcatchment 6S: 6S Tc=5.0 min CN=98 Runoff=17.66 cfs 1.382 af Runoff Area=246,382 sf 0.60% Impervious Runoff Depth=1.16"Subcatchment 7S: 7S Flow Length=839' Tc=10.6 min CN=59 Runoff=5.69 cfs 0.547 af Peak Elev=38.03' Storage=9,030 cf Inflow=6.47 cfs 0.570 afPond 2P: Outflow=1.15 cfs 0.570 af Peak Elev=34.86' Storage=14,844 cf Inflow=6.32 cfs 0.791 afPond 4P: Outflow=1.06 cfs 0.791 af Total Runoff Area = 17.743 ac Runoff Volume = 3.335 af Average Runoff Depth = 2.26" 58.55% Pervious = 10.388 ac 41.45% Impervious = 7.355 ac 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 22HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: 1S Runoff =0.43 cfs @ 12.20 hrs, Volume=0.044 af, Depth= 1.16" Routed to nonexistent node DP1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 29 98 Paved parking, HSG B 688 96 Gravel surface, HSG B 15,352 55 Woods, Good, HSG B 3,784 69 50-75% Grass cover, Fair, HSG B 19,853 59 Weighted Average 19,824 99.85% Pervious Area 29 0.15% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.1 42 0.0780 0.12 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.7 8 0.0827 0.19 Sheet Flow, B-C Grass: Short n= 0.150 P2= 3.35" 6.0 325 0.0081 0.90 Shallow Concentrated Flow, C-D Nearly Bare & Untilled Kv= 10.0 fps 12.8 375 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 23HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 1S: 1S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=19,853 sf Runoff Volume=0.044 af Runoff Depth=1.16" Flow Length=375' Tc=12.8 min CN=59 0.43 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 24HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S Runoff =6.47 cfs @ 12.18 hrs, Volume=0.570 af, Depth= 2.69" Routed to Pond 2P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 41,929 98 Paved parking, HSG B 19,624 55 Woods, Good, HSG B 43,305 69 50-75% Grass cover, Fair, HSG B *5,961 98 Water surface 110,819 79 Weighted Average 62,929 56.79% Pervious Area 47,890 43.21% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 7.8 50 0.0594 0.11 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 3.3 123 0.0077 0.61 Shallow Concentrated Flow, B-C Short Grass Pasture Kv= 7.0 fps 0.8 106 0.0132 2.33 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 21 0.0191 6.79 5.33 Pipe Channel, D-E 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 51 0.0039 3.07 2.41 Pipe Channel, E-F 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0178 6.56 5.15 Pipe Channel, F-G 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 68 0.0177 6.04 4.74 Pipe Channel, G-H 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 12.7 481 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 25HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)7 6 5 4 3 2 1 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=110,819 sf Runoff Volume=0.570 af Runoff Depth=2.69" Flow Length=481' Tc=12.7 min CN=79 6.47 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 26HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.00 cfs @ 24.03 hrs, Volume=0.000 af, Depth= 0.00" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 30,409 30 Woods, Good, HSG A 30,409 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.4 50 0.0108 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 1.3 110 0.0080 1.44 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.7 160 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.001 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=30,409 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=160' Tc=16.7 min CN=30 0.00 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 27HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: 4S Runoff =6.32 cfs @ 12.42 hrs, Volume=0.791 af, Depth= 2.26" Routed to Pond 4P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 546 98 Roofs, HSG A 105,115 98 Paved parking, HSG A 57,593 30 Woods, Good, HSG A 10,223 49 50-75% Grass cover, Fair, HSG A *9,399 98 Water surface 182,876 74 Weighted Average 67,816 37.08% Pervious Area 115,060 62.92% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 19.8 50 0.0058 0.04 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 7.9 207 0.0076 0.44 Shallow Concentrated Flow, B-C Woodland Kv= 5.0 fps 0.7 124 0.0189 2.79 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 53 0.0094 6.24 11.03 Pipe Channel, D-E 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.2 58 0.0052 4.64 8.21 Pipe Channel, E-F 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.4 189 0.0090 7.40 23.25 Pipe Channel, F-G 24.0" Round Area= 3.1 sf Perim= 6.3' r= 0.50' n= 0.012 Corrugated PP, smooth interior 29.1 681 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 28HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 4S: 4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)7 6 5 4 3 2 1 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=182,876 sf Runoff Volume=0.791 af Runoff Depth=2.26" Flow Length=681' Tc=29.1 min CN=74 6.32 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 29HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.00 cfs @ 24.02 hrs, Volume=0.000 af, Depth= 0.00" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0 0 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=26,613 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=73' Tc=13.6 min CN=30 0.00 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 30HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 6S: 6S Runoff =17.66 cfs @ 12.07 hrs, Volume=1.382 af, Depth= 4.63" Routed to nonexistent node DP6 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 155,921 98 Roofs, HSG B 155,921 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Subcatchment 6S: 6S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=155,921 sf Runoff Volume=1.382 af Runoff Depth=4.63" Tc=5.0 min CN=98 17.66 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 31HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 7S: 7S Runoff =5.69 cfs @ 12.17 hrs, Volume=0.547 af, Depth= 1.16" Routed to nonexistent node DP7 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 1,475 98 Paved parking, HSG B 9,035 85 Gravel roads, HSG B 187,932 55 Woods, Good, HSG B 47,940 69 50-75% Grass cover, Fair, HSG B 246,382 59 Weighted Average 244,907 99.40% Pervious Area 1,475 0.60% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 1.7 50 0.0513 0.50 Sheet Flow, A-B n= 0.054 P2= 3.35" 8.9 789 0.0084 1.48 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 10.6 839 Total Subcatchment 7S: 7S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)6 5 4 3 2 1 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=246,382 sf Runoff Volume=0.547 af Runoff Depth=1.16" Flow Length=839' Tc=10.6 min CN=59 5.69 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 32HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2P: Inflow Area =2.544 ac, 43.21% Impervious, Inflow Depth = 2.69" for 10-year event Inflow =6.47 cfs @ 12.18 hrs, Volume=0.570 af Outflow =1.15 cfs @ 12.79 hrs, Volume=0.570 af, Atten= 82%, Lag= 36.9 min Discarded =1.15 cfs @ 12.79 hrs, Volume=0.570 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 38.03' @ 12.79 hrs Surf.Area= 6,007 sf Storage= 9,030 cf Plug-Flow detention time= 75.0 min calculated for 0.570 af (100% of inflow) Center-of-Mass det. time= 75.0 min ( 906.8 - 831.8 ) Volume Invert Avail.Storage Storage Description #1 35.50'24,948 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 35.50 0 0.0 0 0 0 36.00 2,356 262.6 393 393 5,488 37.00 4,397 313.8 3,324 3,717 7,854 38.00 5,961 348.7 5,159 8,876 9,724 39.00 7,857 409.9 6,887 15,763 13,437 40.00 10,581 504.9 9,185 24,948 20,368 Device Routing Invert Outlet Devices #1 Discarded 35.50'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.15 cfs @ 12.79 hrs HW=38.03' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.15 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 33HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)7 6 5 4 3 2 1 0 Inflow Area=2.544 ac Peak Elev=38.03' Storage=9,030 cf 6.47 cfs 1.15 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 34HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 4P: Inflow Area =4.198 ac, 62.92% Impervious, Inflow Depth = 2.26" for 10-year event Inflow =6.32 cfs @ 12.42 hrs, Volume=0.791 af Outflow =1.06 cfs @ 13.62 hrs, Volume=0.791 af, Atten= 83%, Lag= 72.5 min Discarded =1.06 cfs @ 13.62 hrs, Volume=0.791 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 34.86' @ 13.62 hrs Surf.Area= 5,535 sf Storage= 14,844 cf Plug-Flow detention time= 167.3 min calculated for 0.791 af (100% of inflow) Center-of-Mass det. time= 167.3 min ( 1,027.4 - 860.2 ) Volume Invert Avail.Storage Storage Description #1 29.90'60,540 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.90 0 0.0 0 0 0 30.00 268 132.9 9 9 1,406 31.00 1,810 321.7 925 934 8,239 32.00 2,713 338.7 2,246 3,180 9,192 33.00 3,659 355.5 3,174 6,354 10,183 34.00 4,643 372.5 4,141 10,496 11,233 35.00 5,693 391.6 5,159 15,655 12,455 36.00 6,820 410.6 6,248 21,903 13,733 37.00 8,030 430.1 7,417 29,319 15,103 38.00 9,399 460.9 8,706 38,025 17,332 39.00 11,092 498.6 10,234 48,259 20,250 40.00 13,510 520.7 12,281 60,540 22,114 Device Routing Invert Outlet Devices #1 Discarded 29.90'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.06 cfs @ 13.62 hrs HW=34.86' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.06 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 35HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 4P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)7 6 5 4 3 2 1 0 Inflow Area=4.198 ac Peak Elev=34.86' Storage=14,844 cf 6.32 cfs 1.06 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 36HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=19,853 sf 0.15% Impervious Runoff Depth=1.72"Subcatchment 1S: 1S Flow Length=375' Tc=12.8 min CN=59 Runoff=0.68 cfs 0.066 af Runoff Area=110,819 sf 43.21% Impervious Runoff Depth=3.52"Subcatchment 2S: 2S Flow Length=481' Tc=12.7 min CN=79 Runoff=8.45 cfs 0.746 af Runoff Area=30,409 sf 0.00% Impervious Runoff Depth=0.05"Subcatchment 3S: 3S Flow Length=160' Tc=16.7 min CN=30 Runoff=0.00 cfs 0.003 af Runoff Area=182,876 sf 62.92% Impervious Runoff Depth=3.03"Subcatchment 4S: 4S Flow Length=681' Tc=29.1 min CN=74 Runoff=8.54 cfs 1.061 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.05"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.00 cfs 0.003 af Runoff Area=155,921 sf 100.00% Impervious Runoff Depth=5.58"Subcatchment 6S: 6S Tc=5.0 min CN=98 Runoff=21.14 cfs 1.665 af Runoff Area=246,382 sf 0.60% Impervious Runoff Depth=1.72"Subcatchment 7S: 7S Flow Length=839' Tc=10.6 min CN=59 Runoff=9.04 cfs 0.813 af Peak Elev=38.57' Storage=12,571 cf Inflow=8.45 cfs 0.746 afPond 2P: Outflow=1.34 cfs 0.746 af Peak Elev=35.89' Storage=21,171 cf Inflow=8.54 cfs 1.061 afPond 4P: Outflow=1.28 cfs 1.061 af Total Runoff Area = 17.743 ac Runoff Volume = 4.357 af Average Runoff Depth = 2.95" 58.55% Pervious = 10.388 ac 41.45% Impervious = 7.355 ac 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 37HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: 1S Runoff =0.68 cfs @ 12.19 hrs, Volume=0.066 af, Depth= 1.72" Routed to nonexistent node DP1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 29 98 Paved parking, HSG B 688 96 Gravel surface, HSG B 15,352 55 Woods, Good, HSG B 3,784 69 50-75% Grass cover, Fair, HSG B 19,853 59 Weighted Average 19,824 99.85% Pervious Area 29 0.15% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.1 42 0.0780 0.12 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.7 8 0.0827 0.19 Sheet Flow, B-C Grass: Short n= 0.150 P2= 3.35" 6.0 325 0.0081 0.90 Shallow Concentrated Flow, C-D Nearly Bare & Untilled Kv= 10.0 fps 12.8 375 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 38HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 1S: 1S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=19,853 sf Runoff Volume=0.066 af Runoff Depth=1.72" Flow Length=375' Tc=12.8 min CN=59 0.68 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 39HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S Runoff =8.45 cfs @ 12.18 hrs, Volume=0.746 af, Depth= 3.52" Routed to Pond 2P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 41,929 98 Paved parking, HSG B 19,624 55 Woods, Good, HSG B 43,305 69 50-75% Grass cover, Fair, HSG B *5,961 98 Water surface 110,819 79 Weighted Average 62,929 56.79% Pervious Area 47,890 43.21% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 7.8 50 0.0594 0.11 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 3.3 123 0.0077 0.61 Shallow Concentrated Flow, B-C Short Grass Pasture Kv= 7.0 fps 0.8 106 0.0132 2.33 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 21 0.0191 6.79 5.33 Pipe Channel, D-E 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 51 0.0039 3.07 2.41 Pipe Channel, E-F 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0178 6.56 5.15 Pipe Channel, F-G 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 68 0.0177 6.04 4.74 Pipe Channel, G-H 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 12.7 481 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 40HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)9 8 7 6 5 4 3 2 1 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=110,819 sf Runoff Volume=0.746 af Runoff Depth=3.52" Flow Length=481' Tc=12.7 min CN=79 8.45 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 41HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.00 cfs @ 16.94 hrs, Volume=0.003 af, Depth= 0.05" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 30,409 30 Woods, Good, HSG A 30,409 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.4 50 0.0108 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 1.3 110 0.0080 1.44 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.7 160 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=30,409 sf Runoff Volume=0.003 af Runoff Depth=0.05" Flow Length=160' Tc=16.7 min CN=30 0.00 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 42HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: 4S Runoff =8.54 cfs @ 12.41 hrs, Volume=1.061 af, Depth= 3.03" Routed to Pond 4P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 546 98 Roofs, HSG A 105,115 98 Paved parking, HSG A 57,593 30 Woods, Good, HSG A 10,223 49 50-75% Grass cover, Fair, HSG A *9,399 98 Water surface 182,876 74 Weighted Average 67,816 37.08% Pervious Area 115,060 62.92% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 19.8 50 0.0058 0.04 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 7.9 207 0.0076 0.44 Shallow Concentrated Flow, B-C Woodland Kv= 5.0 fps 0.7 124 0.0189 2.79 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 53 0.0094 6.24 11.03 Pipe Channel, D-E 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.2 58 0.0052 4.64 8.21 Pipe Channel, E-F 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.4 189 0.0090 7.40 23.25 Pipe Channel, F-G 24.0" Round Area= 3.1 sf Perim= 6.3' r= 0.50' n= 0.012 Corrugated PP, smooth interior 29.1 681 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 43HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 4S: 4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)9 8 7 6 5 4 3 2 1 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=182,876 sf Runoff Volume=1.061 af Runoff Depth=3.03" Flow Length=681' Tc=29.1 min CN=74 8.54 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 44HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.00 cfs @ 16.85 hrs, Volume=0.003 af, Depth= 0.05" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.004 0.004 0.004 0.004 0.003 0.003 0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=26,613 sf Runoff Volume=0.003 af Runoff Depth=0.05" Flow Length=73' Tc=13.6 min CN=30 0.00 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 45HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 6S: 6S Runoff =21.14 cfs @ 12.07 hrs, Volume=1.665 af, Depth= 5.58" Routed to nonexistent node DP6 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 155,921 98 Roofs, HSG B 155,921 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Subcatchment 6S: 6S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=155,921 sf Runoff Volume=1.665 af Runoff Depth=5.58" Tc=5.0 min CN=98 21.14 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 46HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 7S: 7S Runoff =9.04 cfs @ 12.16 hrs, Volume=0.813 af, Depth= 1.72" Routed to nonexistent node DP7 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 1,475 98 Paved parking, HSG B 9,035 85 Gravel roads, HSG B 187,932 55 Woods, Good, HSG B 47,940 69 50-75% Grass cover, Fair, HSG B 246,382 59 Weighted Average 244,907 99.40% Pervious Area 1,475 0.60% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 1.7 50 0.0513 0.50 Sheet Flow, A-B n= 0.054 P2= 3.35" 8.9 789 0.0084 1.48 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 10.6 839 Total Subcatchment 7S: 7S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=246,382 sf Runoff Volume=0.813 af Runoff Depth=1.72" Flow Length=839' Tc=10.6 min CN=59 9.04 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 47HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2P: Inflow Area =2.544 ac, 43.21% Impervious, Inflow Depth = 3.52" for 25-year event Inflow =8.45 cfs @ 12.18 hrs, Volume=0.746 af Outflow =1.34 cfs @ 12.85 hrs, Volume=0.746 af, Atten= 84%, Lag= 40.4 min Discarded =1.34 cfs @ 12.85 hrs, Volume=0.746 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 38.57' @ 12.85 hrs Surf.Area= 7,010 sf Storage= 12,571 cf Plug-Flow detention time= 93.8 min calculated for 0.746 af (100% of inflow) Center-of-Mass det. time= 93.8 min ( 917.9 - 824.1 ) Volume Invert Avail.Storage Storage Description #1 35.50'24,948 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 35.50 0 0.0 0 0 0 36.00 2,356 262.6 393 393 5,488 37.00 4,397 313.8 3,324 3,717 7,854 38.00 5,961 348.7 5,159 8,876 9,724 39.00 7,857 409.9 6,887 15,763 13,437 40.00 10,581 504.9 9,185 24,948 20,368 Device Routing Invert Outlet Devices #1 Discarded 35.50'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.34 cfs @ 12.85 hrs HW=38.57' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.34 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 48HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)9 8 7 6 5 4 3 2 1 0 Inflow Area=2.544 ac Peak Elev=38.57' Storage=12,571 cf 8.45 cfs 1.34 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 49HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 4P: Inflow Area =4.198 ac, 62.92% Impervious, Inflow Depth = 3.03" for 25-year event Inflow =8.54 cfs @ 12.41 hrs, Volume=1.061 af Outflow =1.28 cfs @ 13.74 hrs, Volume=1.061 af, Atten= 85%, Lag= 80.1 min Discarded =1.28 cfs @ 13.74 hrs, Volume=1.061 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.89' @ 13.74 hrs Surf.Area= 6,693 sf Storage= 21,171 cf Plug-Flow detention time= 201.8 min calculated for 1.061 af (100% of inflow) Center-of-Mass det. time= 201.7 min ( 1,053.4 - 851.6 ) Volume Invert Avail.Storage Storage Description #1 29.90'60,540 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.90 0 0.0 0 0 0 30.00 268 132.9 9 9 1,406 31.00 1,810 321.7 925 934 8,239 32.00 2,713 338.7 2,246 3,180 9,192 33.00 3,659 355.5 3,174 6,354 10,183 34.00 4,643 372.5 4,141 10,496 11,233 35.00 5,693 391.6 5,159 15,655 12,455 36.00 6,820 410.6 6,248 21,903 13,733 37.00 8,030 430.1 7,417 29,319 15,103 38.00 9,399 460.9 8,706 38,025 17,332 39.00 11,092 498.6 10,234 48,259 20,250 40.00 13,510 520.7 12,281 60,540 22,114 Device Routing Invert Outlet Devices #1 Discarded 29.90'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.28 cfs @ 13.74 hrs HW=35.89' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.28 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 50HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 4P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)9 8 7 6 5 4 3 2 1 0 Inflow Area=4.198 ac Peak Elev=35.89' Storage=21,171 cf 8.54 cfs 1.28 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 51HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=19,853 sf 0.15% Impervious Runoff Depth=2.19"Subcatchment 1S: 1S Flow Length=375' Tc=12.8 min CN=59 Runoff=0.89 cfs 0.083 af Runoff Area=110,819 sf 43.21% Impervious Runoff Depth=4.17"Subcatchment 2S: 2S Flow Length=481' Tc=12.7 min CN=79 Runoff=9.97 cfs 0.883 af Runoff Area=30,409 sf 0.00% Impervious Runoff Depth=0.14"Subcatchment 3S: 3S Flow Length=160' Tc=16.7 min CN=30 Runoff=0.01 cfs 0.008 af Runoff Area=182,876 sf 62.92% Impervious Runoff Depth=3.64"Subcatchment 4S: 4S Flow Length=681' Tc=29.1 min CN=74 Runoff=10.28 cfs 1.275 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.14"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.01 cfs 0.007 af Runoff Area=155,921 sf 100.00% Impervious Runoff Depth=6.30"Subcatchment 6S: 6S Tc=5.0 min CN=98 Runoff=23.78 cfs 1.880 af Runoff Area=246,382 sf 0.60% Impervious Runoff Depth=2.19"Subcatchment 7S: 7S Flow Length=839' Tc=10.6 min CN=59 Runoff=11.81 cfs 1.033 af Peak Elev=38.96' Storage=15,412 cf Inflow=9.97 cfs 0.883 afPond 2P: Outflow=1.49 cfs 0.883 af Peak Elev=36.61' Storage=26,317 cf Inflow=10.28 cfs 1.275 afPond 4P: Outflow=1.45 cfs 1.275 af Total Runoff Area = 17.743 ac Runoff Volume = 5.169 af Average Runoff Depth = 3.50" 58.55% Pervious = 10.388 ac 41.45% Impervious = 7.355 ac 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 52HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: 1S Runoff =0.89 cfs @ 12.19 hrs, Volume=0.083 af, Depth= 2.19" Routed to nonexistent node DP1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 29 98 Paved parking, HSG B 688 96 Gravel surface, HSG B 15,352 55 Woods, Good, HSG B 3,784 69 50-75% Grass cover, Fair, HSG B 19,853 59 Weighted Average 19,824 99.85% Pervious Area 29 0.15% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.1 42 0.0780 0.12 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.7 8 0.0827 0.19 Sheet Flow, B-C Grass: Short n= 0.150 P2= 3.35" 6.0 325 0.0081 0.90 Shallow Concentrated Flow, C-D Nearly Bare & Untilled Kv= 10.0 fps 12.8 375 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 53HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 1S: 1S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=19,853 sf Runoff Volume=0.083 af Runoff Depth=2.19" Flow Length=375' Tc=12.8 min CN=59 0.89 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 54HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S Runoff =9.97 cfs @ 12.17 hrs, Volume=0.883 af, Depth= 4.17" Routed to Pond 2P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 41,929 98 Paved parking, HSG B 19,624 55 Woods, Good, HSG B 43,305 69 50-75% Grass cover, Fair, HSG B *5,961 98 Water surface 110,819 79 Weighted Average 62,929 56.79% Pervious Area 47,890 43.21% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 7.8 50 0.0594 0.11 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 3.3 123 0.0077 0.61 Shallow Concentrated Flow, B-C Short Grass Pasture Kv= 7.0 fps 0.8 106 0.0132 2.33 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 21 0.0191 6.79 5.33 Pipe Channel, D-E 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 51 0.0039 3.07 2.41 Pipe Channel, E-F 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0178 6.56 5.15 Pipe Channel, F-G 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 68 0.0177 6.04 4.74 Pipe Channel, G-H 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 12.7 481 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 55HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=110,819 sf Runoff Volume=0.883 af Runoff Depth=4.17" Flow Length=481' Tc=12.7 min CN=79 9.97 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 56HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.01 cfs @ 15.05 hrs, Volume=0.008 af, Depth= 0.14" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 30,409 30 Woods, Good, HSG A 30,409 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.4 50 0.0108 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 1.3 110 0.0080 1.44 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.7 160 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.014 0.013 0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=30,409 sf Runoff Volume=0.008 af Runoff Depth=0.14" Flow Length=160' Tc=16.7 min CN=30 0.01 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 57HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: 4S Runoff =10.28 cfs @ 12.39 hrs, Volume=1.275 af, Depth= 3.64" Routed to Pond 4P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 546 98 Roofs, HSG A 105,115 98 Paved parking, HSG A 57,593 30 Woods, Good, HSG A 10,223 49 50-75% Grass cover, Fair, HSG A *9,399 98 Water surface 182,876 74 Weighted Average 67,816 37.08% Pervious Area 115,060 62.92% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 19.8 50 0.0058 0.04 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 7.9 207 0.0076 0.44 Shallow Concentrated Flow, B-C Woodland Kv= 5.0 fps 0.7 124 0.0189 2.79 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 53 0.0094 6.24 11.03 Pipe Channel, D-E 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.2 58 0.0052 4.64 8.21 Pipe Channel, E-F 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.4 189 0.0090 7.40 23.25 Pipe Channel, F-G 24.0" Round Area= 3.1 sf Perim= 6.3' r= 0.50' n= 0.012 Corrugated PP, smooth interior 29.1 681 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 58HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 4S: 4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=182,876 sf Runoff Volume=1.275 af Runoff Depth=3.64" Flow Length=681' Tc=29.1 min CN=74 10.28 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 59HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.01 cfs @ 14.98 hrs, Volume=0.007 af, Depth= 0.14" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=26,613 sf Runoff Volume=0.007 af Runoff Depth=0.14" Flow Length=73' Tc=13.6 min CN=30 0.01 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 60HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 6S: 6S Runoff =23.78 cfs @ 12.07 hrs, Volume=1.880 af, Depth= 6.30" Routed to nonexistent node DP6 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 155,921 98 Roofs, HSG B 155,921 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Subcatchment 6S: 6S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=155,921 sf Runoff Volume=1.880 af Runoff Depth=6.30" Tc=5.0 min CN=98 23.78 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 61HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 7S: 7S Runoff =11.81 cfs @ 12.16 hrs, Volume=1.033 af, Depth= 2.19" Routed to nonexistent node DP7 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 1,475 98 Paved parking, HSG B 9,035 85 Gravel roads, HSG B 187,932 55 Woods, Good, HSG B 47,940 69 50-75% Grass cover, Fair, HSG B 246,382 59 Weighted Average 244,907 99.40% Pervious Area 1,475 0.60% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 1.7 50 0.0513 0.50 Sheet Flow, A-B n= 0.054 P2= 3.35" 8.9 789 0.0084 1.48 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 10.6 839 Total Subcatchment 7S: 7S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=246,382 sf Runoff Volume=1.033 af Runoff Depth=2.19" Flow Length=839' Tc=10.6 min CN=59 11.81 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 62HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2P: Inflow Area =2.544 ac, 43.21% Impervious, Inflow Depth = 4.17" for 50-year event Inflow =9.97 cfs @ 12.17 hrs, Volume=0.883 af Outflow =1.49 cfs @ 12.89 hrs, Volume=0.883 af, Atten= 85%, Lag= 42.7 min Discarded =1.49 cfs @ 12.89 hrs, Volume=0.883 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 38.96' @ 12.89 hrs Surf.Area= 7,766 sf Storage= 15,412 cf Plug-Flow detention time= 106.7 min calculated for 0.883 af (100% of inflow) Center-of-Mass det. time= 106.7 min ( 926.0 - 819.3 ) Volume Invert Avail.Storage Storage Description #1 35.50'24,948 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 35.50 0 0.0 0 0 0 36.00 2,356 262.6 393 393 5,488 37.00 4,397 313.8 3,324 3,717 7,854 38.00 5,961 348.7 5,159 8,876 9,724 39.00 7,857 409.9 6,887 15,763 13,437 40.00 10,581 504.9 9,185 24,948 20,368 Device Routing Invert Outlet Devices #1 Discarded 35.50'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.49 cfs @ 12.89 hrs HW=38.96' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.49 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 63HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=2.544 ac Peak Elev=38.96' Storage=15,412 cf 9.97 cfs 1.49 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 64HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 4P: Inflow Area =4.198 ac, 62.92% Impervious, Inflow Depth = 3.64" for 50-year event Inflow =10.28 cfs @ 12.39 hrs, Volume=1.275 af Outflow =1.45 cfs @ 13.82 hrs, Volume=1.275 af, Atten= 86%, Lag= 85.8 min Discarded =1.45 cfs @ 13.82 hrs, Volume=1.275 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 36.61' @ 13.82 hrs Surf.Area= 7,552 sf Storage= 26,317 cf Plug-Flow detention time= 224.5 min calculated for 1.275 af (100% of inflow) Center-of-Mass det. time= 224.5 min ( 1,070.9 - 846.3 ) Volume Invert Avail.Storage Storage Description #1 29.90'60,540 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.90 0 0.0 0 0 0 30.00 268 132.9 9 9 1,406 31.00 1,810 321.7 925 934 8,239 32.00 2,713 338.7 2,246 3,180 9,192 33.00 3,659 355.5 3,174 6,354 10,183 34.00 4,643 372.5 4,141 10,496 11,233 35.00 5,693 391.6 5,159 15,655 12,455 36.00 6,820 410.6 6,248 21,903 13,733 37.00 8,030 430.1 7,417 29,319 15,103 38.00 9,399 460.9 8,706 38,025 17,332 39.00 11,092 498.6 10,234 48,259 20,250 40.00 13,510 520.7 12,281 60,540 22,114 Device Routing Invert Outlet Devices #1 Discarded 29.90'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.45 cfs @ 13.82 hrs HW=36.61' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.45 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 65HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 4P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=4.198 ac Peak Elev=36.61' Storage=26,317 cf 10.28 cfs 1.45 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 66HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=19,853 sf 0.15% Impervious Runoff Depth=2.70"Subcatchment 1S: 1S Flow Length=375' Tc=12.8 min CN=59 Runoff=1.12 cfs 0.103 af Runoff Area=110,819 sf 43.21% Impervious Runoff Depth=4.84"Subcatchment 2S: 2S Flow Length=481' Tc=12.7 min CN=79 Runoff=11.55 cfs 1.026 af Runoff Area=30,409 sf 0.00% Impervious Runoff Depth=0.26"Subcatchment 3S: 3S Flow Length=160' Tc=16.7 min CN=30 Runoff=0.03 cfs 0.015 af Runoff Area=182,876 sf 62.92% Impervious Runoff Depth=4.29"Subcatchment 4S: 4S Flow Length=681' Tc=29.1 min CN=74 Runoff=12.10 cfs 1.500 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.26"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.02 cfs 0.013 af Runoff Area=155,921 sf 100.00% Impervious Runoff Depth=7.04"Subcatchment 6S: 6S Tc=5.0 min CN=98 Runoff=26.49 cfs 2.100 af Runoff Area=246,382 sf 0.60% Impervious Runoff Depth=2.70"Subcatchment 7S: 7S Flow Length=839' Tc=10.6 min CN=59 Runoff=14.83 cfs 1.274 af Peak Elev=39.32' Storage=18,413 cf Inflow=11.55 cfs 1.026 afPond 2P: Outflow=1.66 cfs 1.026 af Peak Elev=37.31' Storage=31,849 cf Inflow=12.10 cfs 1.500 afPond 4P: Outflow=1.62 cfs 1.500 af Total Runoff Area = 17.743 ac Runoff Volume = 6.031 af Average Runoff Depth = 4.08" 58.55% Pervious = 10.388 ac 41.45% Impervious = 7.355 ac 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 67HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: 1S Runoff =1.12 cfs @ 12.19 hrs, Volume=0.103 af, Depth= 2.70" Routed to nonexistent node DP1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 29 98 Paved parking, HSG B 688 96 Gravel surface, HSG B 15,352 55 Woods, Good, HSG B 3,784 69 50-75% Grass cover, Fair, HSG B 19,853 59 Weighted Average 19,824 99.85% Pervious Area 29 0.15% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.1 42 0.0780 0.12 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.7 8 0.0827 0.19 Sheet Flow, B-C Grass: Short n= 0.150 P2= 3.35" 6.0 325 0.0081 0.90 Shallow Concentrated Flow, C-D Nearly Bare & Untilled Kv= 10.0 fps 12.8 375 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 68HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 1S: 1S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=19,853 sf Runoff Volume=0.103 af Runoff Depth=2.70" Flow Length=375' Tc=12.8 min CN=59 1.12 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 69HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S Runoff =11.55 cfs @ 12.17 hrs, Volume=1.026 af, Depth= 4.84" Routed to Pond 2P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 41,929 98 Paved parking, HSG B 19,624 55 Woods, Good, HSG B 43,305 69 50-75% Grass cover, Fair, HSG B *5,961 98 Water surface 110,819 79 Weighted Average 62,929 56.79% Pervious Area 47,890 43.21% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 7.8 50 0.0594 0.11 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 3.3 123 0.0077 0.61 Shallow Concentrated Flow, B-C Short Grass Pasture Kv= 7.0 fps 0.8 106 0.0132 2.33 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 21 0.0191 6.79 5.33 Pipe Channel, D-E 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 51 0.0039 3.07 2.41 Pipe Channel, E-F 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0178 6.56 5.15 Pipe Channel, F-G 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 68 0.0177 6.04 4.74 Pipe Channel, G-H 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 12.7 481 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 70HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=110,819 sf Runoff Volume=1.026 af Runoff Depth=4.84" Flow Length=481' Tc=12.7 min CN=79 11.55 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 71HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.03 cfs @ 13.75 hrs, Volume=0.015 af, Depth= 0.26" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 30,409 30 Woods, Good, HSG A 30,409 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.4 50 0.0108 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 1.3 110 0.0080 1.44 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.7 160 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=30,409 sf Runoff Volume=0.015 af Runoff Depth=0.26" Flow Length=160' Tc=16.7 min CN=30 0.03 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 72HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: 4S Runoff =12.10 cfs @ 12.39 hrs, Volume=1.500 af, Depth= 4.29" Routed to Pond 4P : Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 546 98 Roofs, HSG A 105,115 98 Paved parking, HSG A 57,593 30 Woods, Good, HSG A 10,223 49 50-75% Grass cover, Fair, HSG A *9,399 98 Water surface 182,876 74 Weighted Average 67,816 37.08% Pervious Area 115,060 62.92% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 19.8 50 0.0058 0.04 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 7.9 207 0.0076 0.44 Shallow Concentrated Flow, B-C Woodland Kv= 5.0 fps 0.7 124 0.0189 2.79 Shallow Concentrated Flow, C-D Paved Kv= 20.3 fps 0.1 53 0.0094 6.24 11.03 Pipe Channel, D-E 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.2 58 0.0052 4.64 8.21 Pipe Channel, E-F 18.0" Round Area= 1.8 sf Perim= 4.7' r= 0.38' n= 0.012 Corrugated PP, smooth interior 0.4 189 0.0090 7.40 23.25 Pipe Channel, F-G 24.0" Round Area= 3.1 sf Perim= 6.3' r= 0.50' n= 0.012 Corrugated PP, smooth interior 29.1 681 Total 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 73HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 4S: 4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=182,876 sf Runoff Volume=1.500 af Runoff Depth=4.29" Flow Length=681' Tc=29.1 min CN=74 12.10 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 74HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.02 cfs @ 13.74 hrs, Volume=0.013 af, Depth= 0.26" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=26,613 sf Runoff Volume=0.013 af Runoff Depth=0.26" Flow Length=73' Tc=13.6 min CN=30 0.02 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 75HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 6S: 6S Runoff =26.49 cfs @ 12.07 hrs, Volume=2.100 af, Depth= 7.04" Routed to nonexistent node DP6 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 155,921 98 Roofs, HSG B 155,921 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Subcatchment 6S: 6S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=155,921 sf Runoff Volume=2.100 af Runoff Depth=7.04" Tc=5.0 min CN=98 26.49 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 76HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 7S: 7S Runoff =14.83 cfs @ 12.16 hrs, Volume=1.274 af, Depth= 2.70" Routed to nonexistent node DP7 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 1,475 98 Paved parking, HSG B 9,035 85 Gravel roads, HSG B 187,932 55 Woods, Good, HSG B 47,940 69 50-75% Grass cover, Fair, HSG B 246,382 59 Weighted Average 244,907 99.40% Pervious Area 1,475 0.60% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 1.7 50 0.0513 0.50 Sheet Flow, A-B n= 0.054 P2= 3.35" 8.9 789 0.0084 1.48 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 10.6 839 Total Subcatchment 7S: 7S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=246,382 sf Runoff Volume=1.274 af Runoff Depth=2.70" Flow Length=839' Tc=10.6 min CN=59 14.83 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 77HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2P: Inflow Area =2.544 ac, 43.21% Impervious, Inflow Depth = 4.84" for 100-year event Inflow =11.55 cfs @ 12.17 hrs, Volume=1.026 af Outflow =1.66 cfs @ 12.90 hrs, Volume=1.026 af, Atten= 86%, Lag= 43.7 min Discarded =1.66 cfs @ 12.90 hrs, Volume=1.026 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 39.32' @ 12.90 hrs Surf.Area= 8,686 sf Storage= 18,413 cf Plug-Flow detention time= 118.3 min calculated for 1.026 af (100% of inflow) Center-of-Mass det. time= 118.2 min ( 933.3 - 815.1 ) Volume Invert Avail.Storage Storage Description #1 35.50'24,948 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 35.50 0 0.0 0 0 0 36.00 2,356 262.6 393 393 5,488 37.00 4,397 313.8 3,324 3,717 7,854 38.00 5,961 348.7 5,159 8,876 9,724 39.00 7,857 409.9 6,887 15,763 13,437 40.00 10,581 504.9 9,185 24,948 20,368 Device Routing Invert Outlet Devices #1 Discarded 35.50'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.66 cfs @ 12.90 hrs HW=39.32' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.66 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 78HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=2.544 ac Peak Elev=39.32' Storage=18,413 cf 11.55 cfs 1.66 cfs 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 79HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 4P: Inflow Area =4.198 ac, 62.92% Impervious, Inflow Depth = 4.29" for 100-year event Inflow =12.10 cfs @ 12.39 hrs, Volume=1.500 af Outflow =1.62 cfs @ 13.88 hrs, Volume=1.500 af, Atten= 87%, Lag= 89.5 min Discarded =1.62 cfs @ 13.88 hrs, Volume=1.500 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 37.31' @ 13.88 hrs Surf.Area= 8,439 sf Storage= 31,849 cf Plug-Flow detention time= 245.4 min calculated for 1.500 af (100% of inflow) Center-of-Mass det. time= 245.4 min ( 1,087.1 - 841.7 ) Volume Invert Avail.Storage Storage Description #1 29.90'60,540 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.90 0 0.0 0 0 0 30.00 268 132.9 9 9 1,406 31.00 1,810 321.7 925 934 8,239 32.00 2,713 338.7 2,246 3,180 9,192 33.00 3,659 355.5 3,174 6,354 10,183 34.00 4,643 372.5 4,141 10,496 11,233 35.00 5,693 391.6 5,159 15,655 12,455 36.00 6,820 410.6 6,248 21,903 13,733 37.00 8,030 430.1 7,417 29,319 15,103 38.00 9,399 460.9 8,706 38,025 17,332 39.00 11,092 498.6 10,234 48,259 20,250 40.00 13,510 520.7 12,281 60,540 22,114 Device Routing Invert Outlet Devices #1 Discarded 29.90'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.62 cfs @ 13.88 hrs HW=37.31' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.62 cfs) 225 White's Path - Predevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path S Yarmouth Existing Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 80HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 4P: Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=4.198 ac Peak Elev=37.31' Storage=31,849 cf 12.10 cfs 1.62 cfs Section 3.1.2 Post-Developed Stormwater Report Calculations 2S 2S/4S 3S 3S 5S 5S 2/4P Proposed Retention/Recharge Basin Routing Diagram for 225 White's Path Yarmouth Proposed Hydrology Prepared by CHA Companies, Inc., Printed 6/15/2022 HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link 225 White's Path - Postdevelopment Hydrology 225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 2HydroCAD® 10.10-6a s/n 01012 © 2020 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 3.35 2 2 10-year Type III 24-hr Default 24.00 1 4.87 2 3 25-year Type III 24-hr Default 24.00 1 5.82 2 4 50-year Type III 24-hr Default 24.00 1 6.54 2 5 100-year Type III 24-hr Default 24.00 1 7.28 2 225 White's Path - Postdevelopment Hydrology 225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 3HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 2.004 49 50-75% Grass cover, Fair, HSG A (2S) 4.135 98 Paved parking, HSG A (2S) 0.013 98 Roofs, HSG A (2S) 0.410 98 Water Surface, HSG A (2S) 1.490 30 Woods, Good, HSG A (2S, 3S, 5S) 8.052 73 TOTAL AREA 225 White's Path - Postdevelopment Hydrology 225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 4HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 8.052 HSG A 2S, 3S, 5S 0.000 HSG B 0.000 HSG C 0.000 HSG D 0.000 Other 8.052 TOTAL AREA 225 White's Path - Postdevelopment Hydrology 225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 5HydroCAD® 10.10-6a s/n 01012 © 2020 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 2.004 0.000 0.000 0.000 0.000 2.004 50-75% Grass cover, Fair 2S 4.135 0.000 0.000 0.000 0.000 4.135 Paved parking 2S 0.013 0.000 0.000 0.000 0.000 0.013 Roofs 2S 0.410 0.000 0.000 0.000 0.000 0.410 Water Surface 2S 1.490 0.000 0.000 0.000 0.000 1.490 Woods, Good 2S, 3S, 5S 8.052 0.000 0.000 0.000 0.000 8.052 TOTAL AREA 225 White's Path - Postdevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 6HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Sim-Route method - Pond routing by Sim-Route method Runoff Area=314,902 sf 63.05% Impervious Runoff Depth=1.38"Subcatchment 2S: 2S/4S Flow Length=782' Tc=6.3 min CN=78 Runoff=11.42 cfs 0.834 af Runoff Area=9,216 sf 0.00% Impervious Runoff Depth=0.00"Subcatchment 3S: 3S Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 Runoff=0.00 cfs 0.000 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.00"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.00 cfs 0.000 af Peak Elev=32.66' Storage=14,359 cf Inflow=11.42 cfs 0.834 afPond 2/4P: Proposed Retention/Recharge Basin Outflow=1.39 cfs 0.835 af Total Runoff Area = 8.052 ac Runoff Volume = 0.834 af Average Runoff Depth = 1.24" 43.39% Pervious = 3.494 ac 56.61% Impervious = 4.558 ac 225 White's Path - Postdevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 7HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S/4S Runoff =11.42 cfs @ 12.10 hrs, Volume=0.834 af, Depth= 1.38" Routed to Pond 2/4P : Proposed Retention/Recharge Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 180,135 98 Paved parking, HSG A 17,873 98 Water Surface, HSG A 87,289 49 50-75% Grass cover, Fair, HSG A 29,059 30 Woods, Good, HSG A 546 98 Roofs, HSG A 314,902 78 Weighted Average 116,348 36.95% Pervious Area 198,554 63.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.5 37 0.0819 0.25 Sheet Flow, AB Grass: Short n= 0.150 P2= 3.35" 1.6 134 0.0075 1.39 Shallow Concentrated Flow, BC Unpaved Kv= 16.1 fps 0.5 109 0.0296 3.49 Shallow Concentrated Flow, CD Paved Kv= 20.3 fps 0.1 21 0.0200 6.95 5.46 Pipe Channel, DE 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 50 0.0040 3.11 2.44 Pipe Channel, EF 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0180 6.59 5.18 Pipe Channel, FG 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.8 259 0.0160 5.74 4.51 Pipe Channel, GH 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.1 20 0.0160 5.74 4.51 Pipe Channel, HI 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.2 90 0.0100 9.44 66.70 Pipe Channel, IJ 36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75' n= 0.013 Corrugated PE, smooth interior 6.3 782 Total 225 White's Path - Postdevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 8HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S/4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=314,902 sf Runoff Volume=0.834 af Runoff Depth=1.38" Flow Length=782' Tc=6.3 min CN=78 11.42 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 9HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Depth= 0.00" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 9,216 30 Woods, Good, HSG A 9,216 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.9 50 0.0100 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.5 45 0.0100 1.61 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.4 95 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=9,216 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 0.00 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 10HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Depth= 0.00" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.35" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type III 24-hr 2-year Rainfall=3.35" Runoff Area=26,613 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=73' Tc=13.6 min CN=30 0.00 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 11HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2/4P: Proposed Retention/Recharge Basin Inflow Area =7.229 ac, 63.05% Impervious, Inflow Depth = 1.38" for 2-year event Inflow =11.42 cfs @ 12.10 hrs, Volume=0.834 af Outflow =1.39 cfs @ 12.93 hrs, Volume=0.835 af, Atten= 88%, Lag= 50.3 min Discarded =1.39 cfs @ 12.93 hrs, Volume=0.835 af Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 32.66' @ 12.93 hrs Surf.Area= 7,257 sf Storage= 14,359 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 118.1 min ( 965.0 - 847.0 ) Volume Invert Avail.Storage Storage Description #1 29.00'109,951 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.00 432 207.0 0 0 432 30.00 2,599 554.0 1,364 1,364 21,449 31.00 4,308 577.0 3,418 4,781 23,595 32.00 6,073 597.0 5,165 9,947 25,554 33.00 7,900 618.0 6,967 16,913 27,673 34.00 9,781 637.0 8,824 25,737 29,672 35.00 11,720 656.0 10,736 36,473 31,731 36.00 13,714 674.0 12,704 49,177 33,749 37.00 15,765 693.0 14,728 63,904 35,925 38.00 17,873 712.0 16,808 80,712 38,163 39.00 20,038 731.0 18,945 99,657 40,461 39.50 21,142 740.0 10,294 109,951 41,577 Device Routing Invert Outlet Devices #1 Discarded 29.00'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.39 cfs @ 12.93 hrs HW=32.66' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.39 cfs) 225 White's Path - Postdevelopment Hydrology Type III 24-hr 2-year Rainfall=3.35"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 12HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2/4P: Proposed Retention/Recharge Basin Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=7.229 ac Peak Elev=32.66' Storage=14,359 cf 11.42 cfs 1.39 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 13HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Sim-Route method - Pond routing by Sim-Route method Runoff Area=314,902 sf 63.05% Impervious Runoff Depth=2.60"Subcatchment 2S: 2S/4S Flow Length=782' Tc=6.3 min CN=78 Runoff=21.83 cfs 1.567 af Runoff Area=9,216 sf 0.00% Impervious Runoff Depth=0.00"Subcatchment 3S: 3S Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 Runoff=0.00 cfs 0.000 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.00"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.00 cfs 0.000 af Peak Elev=34.50' Storage=30,828 cf Inflow=21.83 cfs 1.567 afPond 2/4P: Proposed Retention/Recharge Basin Outflow=2.05 cfs 1.568 af Total Runoff Area = 8.052 ac Runoff Volume = 1.567 af Average Runoff Depth = 2.34" 43.39% Pervious = 3.494 ac 56.61% Impervious = 4.558 ac 225 White's Path - Postdevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 14HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S/4S Runoff =21.83 cfs @ 12.09 hrs, Volume=1.567 af, Depth= 2.60" Routed to Pond 2/4P : Proposed Retention/Recharge Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 180,135 98 Paved parking, HSG A 17,873 98 Water Surface, HSG A 87,289 49 50-75% Grass cover, Fair, HSG A 29,059 30 Woods, Good, HSG A 546 98 Roofs, HSG A 314,902 78 Weighted Average 116,348 36.95% Pervious Area 198,554 63.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.5 37 0.0819 0.25 Sheet Flow, AB Grass: Short n= 0.150 P2= 3.35" 1.6 134 0.0075 1.39 Shallow Concentrated Flow, BC Unpaved Kv= 16.1 fps 0.5 109 0.0296 3.49 Shallow Concentrated Flow, CD Paved Kv= 20.3 fps 0.1 21 0.0200 6.95 5.46 Pipe Channel, DE 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 50 0.0040 3.11 2.44 Pipe Channel, EF 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0180 6.59 5.18 Pipe Channel, FG 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.8 259 0.0160 5.74 4.51 Pipe Channel, GH 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.1 20 0.0160 5.74 4.51 Pipe Channel, HI 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.2 90 0.0100 9.44 66.70 Pipe Channel, IJ 36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75' n= 0.013 Corrugated PE, smooth interior 6.3 782 Total 225 White's Path - Postdevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 15HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S/4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=314,902 sf Runoff Volume=1.567 af Runoff Depth=2.60" Flow Length=782' Tc=6.3 min CN=78 21.83 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 16HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.00 cfs @ 24.03 hrs, Volume=0.000 af, Depth= 0.00" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 9,216 30 Woods, Good, HSG A 9,216 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.9 50 0.0100 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.5 45 0.0100 1.61 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.4 95 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0 0 0 0 0 0 0 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=9,216 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 0.00 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 17HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.00 cfs @ 24.02 hrs, Volume=0.000 af, Depth= 0.00" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.87" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0 0 0 Type III 24-hr 10-year Rainfall=4.87" Runoff Area=26,613 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=73' Tc=13.6 min CN=30 0.00 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 18HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2/4P: Proposed Retention/Recharge Basin Inflow Area =7.229 ac, 63.05% Impervious, Inflow Depth = 2.60" for 10-year event Inflow =21.83 cfs @ 12.09 hrs, Volume=1.567 af Outflow =2.05 cfs @ 13.09 hrs, Volume=1.568 af, Atten= 91%, Lag= 59.8 min Discarded =2.05 cfs @ 13.09 hrs, Volume=1.568 af Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 34.50' @ 13.09 hrs Surf.Area= 10,722 sf Storage= 30,828 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 180.2 min ( 1,008.8 - 828.6 ) Volume Invert Avail.Storage Storage Description #1 29.00'109,951 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.00 432 207.0 0 0 432 30.00 2,599 554.0 1,364 1,364 21,449 31.00 4,308 577.0 3,418 4,781 23,595 32.00 6,073 597.0 5,165 9,947 25,554 33.00 7,900 618.0 6,967 16,913 27,673 34.00 9,781 637.0 8,824 25,737 29,672 35.00 11,720 656.0 10,736 36,473 31,731 36.00 13,714 674.0 12,704 49,177 33,749 37.00 15,765 693.0 14,728 63,904 35,925 38.00 17,873 712.0 16,808 80,712 38,163 39.00 20,038 731.0 18,945 99,657 40,461 39.50 21,142 740.0 10,294 109,951 41,577 Device Routing Invert Outlet Devices #1 Discarded 29.00'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=2.05 cfs @ 13.09 hrs HW=34.50' (Free Discharge) 1=Exfiltration (Exfiltration Controls 2.05 cfs) 225 White's Path - Postdevelopment Hydrology Type III 24-hr 10-year Rainfall=4.87"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 19HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2/4P: Proposed Retention/Recharge Basin Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=7.229 ac Peak Elev=34.50' Storage=30,828 cf 21.83 cfs 2.05 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 20HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Sim-Route method - Pond routing by Sim-Route method Runoff Area=314,902 sf 63.05% Impervious Runoff Depth=3.42"Subcatchment 2S: 2S/4S Flow Length=782' Tc=6.3 min CN=78 Runoff=28.68 cfs 2.061 af Runoff Area=9,216 sf 0.00% Impervious Runoff Depth=0.05"Subcatchment 3S: 3S Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 Runoff=0.00 cfs 0.001 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.05"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.00 cfs 0.003 af Peak Elev=35.50' Storage=42,573 cf Inflow=28.68 cfs 2.061 afPond 2/4P: Proposed Retention/Recharge Basin Outflow=2.43 cfs 2.062 af Total Runoff Area = 8.052 ac Runoff Volume = 2.064 af Average Runoff Depth = 3.08" 43.39% Pervious = 3.494 ac 56.61% Impervious = 4.558 ac 225 White's Path - Postdevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 21HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S/4S Runoff =28.68 cfs @ 12.09 hrs, Volume=2.061 af, Depth= 3.42" Routed to Pond 2/4P : Proposed Retention/Recharge Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 180,135 98 Paved parking, HSG A 17,873 98 Water Surface, HSG A 87,289 49 50-75% Grass cover, Fair, HSG A 29,059 30 Woods, Good, HSG A 546 98 Roofs, HSG A 314,902 78 Weighted Average 116,348 36.95% Pervious Area 198,554 63.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.5 37 0.0819 0.25 Sheet Flow, AB Grass: Short n= 0.150 P2= 3.35" 1.6 134 0.0075 1.39 Shallow Concentrated Flow, BC Unpaved Kv= 16.1 fps 0.5 109 0.0296 3.49 Shallow Concentrated Flow, CD Paved Kv= 20.3 fps 0.1 21 0.0200 6.95 5.46 Pipe Channel, DE 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 50 0.0040 3.11 2.44 Pipe Channel, EF 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0180 6.59 5.18 Pipe Channel, FG 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.8 259 0.0160 5.74 4.51 Pipe Channel, GH 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.1 20 0.0160 5.74 4.51 Pipe Channel, HI 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.2 90 0.0100 9.44 66.70 Pipe Channel, IJ 36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75' n= 0.013 Corrugated PE, smooth interior 6.3 782 Total 225 White's Path - Postdevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 22HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S/4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=314,902 sf Runoff Volume=2.061 af Runoff Depth=3.42" Flow Length=782' Tc=6.3 min CN=78 28.68 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 23HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.00 cfs @ 16.89 hrs, Volume=0.001 af, Depth= 0.05" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 9,216 30 Woods, Good, HSG A 9,216 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.9 50 0.0100 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.5 45 0.0100 1.61 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.4 95 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=9,216 sf Runoff Volume=0.001 af Runoff Depth=0.05" Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 0.00 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 24HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.00 cfs @ 16.85 hrs, Volume=0.003 af, Depth= 0.05" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.004 0.004 0.004 0.004 0.003 0.003 0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0 Type III 24-hr 25-year Rainfall=5.82" Runoff Area=26,613 sf Runoff Volume=0.003 af Runoff Depth=0.05" Flow Length=73' Tc=13.6 min CN=30 0.00 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 25HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2/4P: Proposed Retention/Recharge Basin Inflow Area =7.229 ac, 63.05% Impervious, Inflow Depth = 3.42" for 25-year event Inflow =28.68 cfs @ 12.09 hrs, Volume=2.061 af Outflow =2.43 cfs @ 13.24 hrs, Volume=2.062 af, Atten= 92%, Lag= 68.9 min Discarded =2.43 cfs @ 13.24 hrs, Volume=2.062 af Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.50' @ 13.24 hrs Surf.Area= 12,697 sf Storage= 42,573 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 212.8 min ( 1,033.5 - 820.7 ) Volume Invert Avail.Storage Storage Description #1 29.00'109,951 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.00 432 207.0 0 0 432 30.00 2,599 554.0 1,364 1,364 21,449 31.00 4,308 577.0 3,418 4,781 23,595 32.00 6,073 597.0 5,165 9,947 25,554 33.00 7,900 618.0 6,967 16,913 27,673 34.00 9,781 637.0 8,824 25,737 29,672 35.00 11,720 656.0 10,736 36,473 31,731 36.00 13,714 674.0 12,704 49,177 33,749 37.00 15,765 693.0 14,728 63,904 35,925 38.00 17,873 712.0 16,808 80,712 38,163 39.00 20,038 731.0 18,945 99,657 40,461 39.50 21,142 740.0 10,294 109,951 41,577 Device Routing Invert Outlet Devices #1 Discarded 29.00'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=2.43 cfs @ 13.24 hrs HW=35.50' (Free Discharge) 1=Exfiltration (Exfiltration Controls 2.43 cfs) 225 White's Path - Postdevelopment Hydrology Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 26HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2/4P: Proposed Retention/Recharge Basin Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=7.229 ac Peak Elev=35.50' Storage=42,573 cf 28.68 cfs 2.43 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 27HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Sim-Route method - Pond routing by Sim-Route method Runoff Area=314,902 sf 63.05% Impervious Runoff Depth=4.06"Subcatchment 2S: 2S/4S Flow Length=782' Tc=6.3 min CN=78 Runoff=33.96 cfs 2.446 af Runoff Area=9,216 sf 0.00% Impervious Runoff Depth=0.14"Subcatchment 3S: 3S Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 Runoff=0.00 cfs 0.002 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.14"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.01 cfs 0.007 af Peak Elev=36.20' Storage=52,024 cf Inflow=33.96 cfs 2.446 afPond 2/4P: Proposed Retention/Recharge Basin Outflow=2.70 cfs 2.447 af Total Runoff Area = 8.052 ac Runoff Volume = 2.455 af Average Runoff Depth = 3.66" 43.39% Pervious = 3.494 ac 56.61% Impervious = 4.558 ac 225 White's Path - Postdevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 28HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S/4S Runoff =33.96 cfs @ 12.09 hrs, Volume=2.446 af, Depth= 4.06" Routed to Pond 2/4P : Proposed Retention/Recharge Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 180,135 98 Paved parking, HSG A 17,873 98 Water Surface, HSG A 87,289 49 50-75% Grass cover, Fair, HSG A 29,059 30 Woods, Good, HSG A 546 98 Roofs, HSG A 314,902 78 Weighted Average 116,348 36.95% Pervious Area 198,554 63.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.5 37 0.0819 0.25 Sheet Flow, AB Grass: Short n= 0.150 P2= 3.35" 1.6 134 0.0075 1.39 Shallow Concentrated Flow, BC Unpaved Kv= 16.1 fps 0.5 109 0.0296 3.49 Shallow Concentrated Flow, CD Paved Kv= 20.3 fps 0.1 21 0.0200 6.95 5.46 Pipe Channel, DE 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 50 0.0040 3.11 2.44 Pipe Channel, EF 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0180 6.59 5.18 Pipe Channel, FG 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.8 259 0.0160 5.74 4.51 Pipe Channel, GH 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.1 20 0.0160 5.74 4.51 Pipe Channel, HI 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.2 90 0.0100 9.44 66.70 Pipe Channel, IJ 36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75' n= 0.013 Corrugated PE, smooth interior 6.3 782 Total 225 White's Path - Postdevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 29HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S/4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=314,902 sf Runoff Volume=2.446 af Runoff Depth=4.06" Flow Length=782' Tc=6.3 min CN=78 33.96 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 30HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.00 cfs @ 15.03 hrs, Volume=0.002 af, Depth= 0.14" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 9,216 30 Woods, Good, HSG A 9,216 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.9 50 0.0100 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.5 45 0.0100 1.61 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.4 95 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.004 0.004 0.004 0.004 0.003 0.003 0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=9,216 sf Runoff Volume=0.002 af Runoff Depth=0.14" Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 0.00 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 31HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.01 cfs @ 14.98 hrs, Volume=0.007 af, Depth= 0.14" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 50-year Rainfall=6.54" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 Type III 24-hr 50-year Rainfall=6.54" Runoff Area=26,613 sf Runoff Volume=0.007 af Runoff Depth=0.14" Flow Length=73' Tc=13.6 min CN=30 0.01 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 32HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2/4P: Proposed Retention/Recharge Basin Inflow Area =7.229 ac, 63.05% Impervious, Inflow Depth = 4.06" for 50-year event Inflow =33.96 cfs @ 12.09 hrs, Volume=2.446 af Outflow =2.70 cfs @ 13.36 hrs, Volume=2.447 af, Atten= 92%, Lag= 76.4 min Discarded =2.70 cfs @ 13.36 hrs, Volume=2.447 af Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 36.20' @ 13.36 hrs Surf.Area= 14,122 sf Storage= 52,024 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 235.1 min ( 1,050.9 - 815.8 ) Volume Invert Avail.Storage Storage Description #1 29.00'109,951 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.00 432 207.0 0 0 432 30.00 2,599 554.0 1,364 1,364 21,449 31.00 4,308 577.0 3,418 4,781 23,595 32.00 6,073 597.0 5,165 9,947 25,554 33.00 7,900 618.0 6,967 16,913 27,673 34.00 9,781 637.0 8,824 25,737 29,672 35.00 11,720 656.0 10,736 36,473 31,731 36.00 13,714 674.0 12,704 49,177 33,749 37.00 15,765 693.0 14,728 63,904 35,925 38.00 17,873 712.0 16,808 80,712 38,163 39.00 20,038 731.0 18,945 99,657 40,461 39.50 21,142 740.0 10,294 109,951 41,577 Device Routing Invert Outlet Devices #1 Discarded 29.00'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=2.70 cfs @ 13.36 hrs HW=36.20' (Free Discharge) 1=Exfiltration (Exfiltration Controls 2.70 cfs) 225 White's Path - Postdevelopment Hydrology Type III 24-hr 50-year Rainfall=6.54"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 33HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2/4P: Proposed Retention/Recharge Basin Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=7.229 ac Peak Elev=36.20' Storage=52,024 cf 33.96 cfs 2.70 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 34HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Sim-Route method - Pond routing by Sim-Route method Runoff Area=314,902 sf 63.05% Impervious Runoff Depth=4.73"Subcatchment 2S: 2S/4S Flow Length=782' Tc=6.3 min CN=78 Runoff=39.43 cfs 2.849 af Runoff Area=9,216 sf 0.00% Impervious Runoff Depth=0.26"Subcatchment 3S: 3S Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 Runoff=0.01 cfs 0.005 af Runoff Area=26,613 sf 0.00% Impervious Runoff Depth=0.26"Subcatchment 5S: 5S Flow Length=73' Tc=13.6 min CN=30 Runoff=0.02 cfs 0.013 af Peak Elev=36.89' Storage=62,144 cf Inflow=39.43 cfs 2.849 afPond 2/4P: Proposed Retention/Recharge Basin Outflow=2.97 cfs 2.850 af Total Runoff Area = 8.052 ac Runoff Volume = 2.867 af Average Runoff Depth = 4.27" 43.39% Pervious = 3.494 ac 56.61% Impervious = 4.558 ac 225 White's Path - Postdevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 35HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: 2S/4S Runoff =39.43 cfs @ 12.09 hrs, Volume=2.849 af, Depth= 4.73" Routed to Pond 2/4P : Proposed Retention/Recharge Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 180,135 98 Paved parking, HSG A 17,873 98 Water Surface, HSG A 87,289 49 50-75% Grass cover, Fair, HSG A 29,059 30 Woods, Good, HSG A 546 98 Roofs, HSG A 314,902 78 Weighted Average 116,348 36.95% Pervious Area 198,554 63.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.5 37 0.0819 0.25 Sheet Flow, AB Grass: Short n= 0.150 P2= 3.35" 1.6 134 0.0075 1.39 Shallow Concentrated Flow, BC Unpaved Kv= 16.1 fps 0.5 109 0.0296 3.49 Shallow Concentrated Flow, CD Paved Kv= 20.3 fps 0.1 21 0.0200 6.95 5.46 Pipe Channel, DE 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 50 0.0040 3.11 2.44 Pipe Channel, EF 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0180 6.59 5.18 Pipe Channel, FG 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.8 259 0.0160 5.74 4.51 Pipe Channel, GH 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.1 20 0.0160 5.74 4.51 Pipe Channel, HI 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.2 90 0.0100 9.44 66.70 Pipe Channel, IJ 36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75' n= 0.013 Corrugated PE, smooth interior 6.3 782 Total 225 White's Path - Postdevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 36HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: 2S/4S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=314,902 sf Runoff Volume=2.849 af Runoff Depth=4.73" Flow Length=782' Tc=6.3 min CN=78 39.43 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 37HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: 3S Runoff =0.01 cfs @ 13.76 hrs, Volume=0.005 af, Depth= 0.26" Routed to nonexistent node DP3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 9,216 30 Woods, Good, HSG A 9,216 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.9 50 0.0100 0.05 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.5 45 0.0100 1.61 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 16.4 95 Total Subcatchment 3S: 3S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.009 0.008 0.007 0.007 0.006 0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=9,216 sf Runoff Volume=0.005 af Runoff Depth=0.26" Flow Length=95' Slope=0.0100 '/' Tc=16.4 min CN=30 0.01 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 38HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: 5S Runoff =0.02 cfs @ 13.74 hrs, Volume=0.013 af, Depth= 0.26" Routed to nonexistent node DP5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.28" Area (sf) CN Description 26,613 30 Woods, Good, HSG A 26,613 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.5 50 0.0150 0.06 Sheet Flow, A-B Woods: Light underbrush n= 0.400 P2= 3.35" 0.1 23 0.0326 2.91 Shallow Concentrated Flow, B-C Unpaved Kv= 16.1 fps 13.6 73 Total Subcatchment 5S: 5S Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type III 24-hr 100-year Rainfall=7.28" Runoff Area=26,613 sf Runoff Volume=0.013 af Runoff Depth=0.26" Flow Length=73' Tc=13.6 min CN=30 0.02 cfs 225 White's Path - Postdevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 39HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 2/4P: Proposed Retention/Recharge Basin Inflow Area =7.229 ac, 63.05% Impervious, Inflow Depth = 4.73" for 100-year event Inflow =39.43 cfs @ 12.09 hrs, Volume=2.849 af Outflow =2.97 cfs @ 13.47 hrs, Volume=2.850 af, Atten= 92%, Lag= 82.7 min Discarded =2.97 cfs @ 13.47 hrs, Volume=2.850 af Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 36.89' @ 13.47 hrs Surf.Area= 15,527 sf Storage= 62,144 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 256.4 min ( 1,067.9 - 811.5 ) Volume Invert Avail.Storage Storage Description #1 29.00'109,951 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.00 432 207.0 0 0 432 30.00 2,599 554.0 1,364 1,364 21,449 31.00 4,308 577.0 3,418 4,781 23,595 32.00 6,073 597.0 5,165 9,947 25,554 33.00 7,900 618.0 6,967 16,913 27,673 34.00 9,781 637.0 8,824 25,737 29,672 35.00 11,720 656.0 10,736 36,473 31,731 36.00 13,714 674.0 12,704 49,177 33,749 37.00 15,765 693.0 14,728 63,904 35,925 38.00 17,873 712.0 16,808 80,712 38,163 39.00 20,038 731.0 18,945 99,657 40,461 39.50 21,142 740.0 10,294 109,951 41,577 Device Routing Invert Outlet Devices #1 Discarded 29.00'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=2.97 cfs @ 13.47 hrs HW=36.89' (Free Discharge) 1=Exfiltration (Exfiltration Controls 2.97 cfs) 225 White's Path - Postdevelopment Hydrology Type III 24-hr 100-year Rainfall=7.28"225 White's Path Yarmouth Proposed Hydrology Printed 6/15/2022Prepared by CHA Companies, Inc. Page 40HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Pond 2/4P: Proposed Retention/Recharge Basin Inflow Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=7.229 ac Peak Elev=36.89' Storage=62,144 cf 39.43 cfs 2.97 cfs Section 3.2 Proposed Pipe Hydraulic Calculations Design Assumptions Project No.72846 25 Year Storm Pipe Coefficient "n"0.013 HDPE/RCP SHEET 1 OF 1 Project 225 White's Path 5 Minute Duration COMPUTED BY DR DATE 6/9/2022 Location 225 White's Path 7.2 in/hr Intensity for IDF Curve DATE Yarmouth MA DATE CHECKED BY DATE RUNOFF RUNOFF RATIONAL METHOD Q=Ca x C x i x A PIPE FROM COEFFICIENT RAINFALL DISCHARGE STRUCTURE FROM TO INTENSITY (Q)MEAN INCREM.INCREM TOTAL LENGTH SLOPE CAPACITY VELOCITY AVAILABLE FROM TO STRUCT.STRUCT.(AC)TOTAL "C""Ca""Ca" X "C" X "A"TC(MIN)TF(MIN) (IN/HR)(CFS) (CFS) (FT)DIA (IN) (FT/FT)Q (CFS)VF (FT/S)CAPACITY INVERT INVERT RIM DMH1 0.10 0.76 1.1 0.09 5 7.2 0.62 55 12 0.005 2.59 3.30 1.97 35.40 35.11 38.90 DMH1 0.18 0.56 1.1 0.11 5 7.2 0.81 58 12 0.005 2.52 3.21 1.71 35.40 35.11 38.90 DMH2 0.29 1.43 118 12 0.005 2.52 3.21 1.09 35.01 34.42 39.80 DMH2 0.13 0.73 1.1 0.10 5 7.2 0.73 38 12 0.011 3.71 4.72 2.97 35.60 35.19 39.10 DMH2 0.15 0.59 1.1 0.10 5 7.2 0.73 41 12 0.016 4.53 5.77 3.80 35.80 35.14 39.30 DMH3 0.57 2.89 91 15 0.005 4.65 3.79 1.76 34.32 33.85 39.50 DMH3 0.54 0.59 1.1 0.35 5 7.2 2.52 65 12 0.010 3.54 4.51 1.02 35.40 34.76 38.90 DMH4 1.11 5.41 70 18 0.005 7.23 4.09 1.82 33.85 33.52 38.90 DMH4 0.23 0.58 1.1 0.14 5 7.2 1.04 5 12 0.020 5.05 6.43 4.01 35.30 35.20 38.80 DMH4 0.41 0.64 1.1 0.29 5 7.2 2.10 74 12 0.010 3.54 4.52 1.45 35.90 35.17 39.40 CDS 1.75 8.54 60 24 0.005 16.03 5.10 7.48 33.42 33.12 39.10 EXCB2 0.63 0.52 1.1 0.36 5 7.2 2.59 75 12 0.007 2.91 3.71 0.32 38.30 37.80 40.50 EXCB3 0.25 0.89 0.90 1.1 0.25 5 7.2 1.80 4.39 42 12 0.007 3.02 3.84 -1.37 37.70 37.40 40.40 EXCB5 0.04 0.62 1.1 0.03 5 7.2 0.21 16 12 0.025 5.64 7.19 5.43 37.80 37.40 40.10 EXCB3 0.16 0.20 0.63 1.1 0.11 5 7.2 0.78 0.99 46 12 0.004 2.35 3.00 1.36 37.70 37.50 40.10 EXCB6 0.52 1.60 0.56 1.1 0.32 5 7.2 2.29 7.67 58 12 0.019 4.91 6.26 -2.75 37.50 36.40 40.20 CDS 0.50 1.60 0.87 1.1 0.48 5 7.2 3.46 7.67 256 15 0.014 7.55 6.15 -0.12 36.60 33.12 40.90 DMH5 3.35 16.21 14 24 0.010 22.67 7.22 6.45 32.87 32.73 39.70 EXCB8 0.29 0.87 1.1 0.28 5 7.2 2.02 40 12 0.015 4.37 5.57 2.35 34.40 33.80 36.90 EXDMH1 0.43 0.72 0.71 1.1 0.33 6 7.2 2.39 4.41 90 12 -0.001 33.90 34.00 36.90 EXDMH2 0.72 4.41 53 12 0.009 3.47 4.42 -0.94 33.80 33.30 36.90 EXDMH2 0.64 0.83 1.1 0.58 6 7.2 4.17 29 12 0.010 3.63 4.62 -0.54 33.60 33.30 37.50 EXDMH3 1.36 8.58 54 12 0.026 5.75 7.32 -2.84 33.30 31.90 36.80 EXCB10 0.19 0.69 1.1 0.14 6 7.2 1.01 76 12 0.007 2.89 3.69 1.89 34.40 33.90 36.80 EXCB11 0.21 0.40 0.74 1.1 0.18 6 7.2 1.27 2.27 129 12 0.005 2.63 3.35 0.36 34.00 33.30 36.70 EXCB12 0.19 0.59 0.70 1.1 0.15 6 7.2 1.06 3.34 44 12 0.009 3.40 4.33 0.07 33.30 32.90 36.90 EXCB13 0.21 0.81 0.77 1.1 0.18 6 7.2 1.29 4.63 61 12 0.003 2.04 2.60 -2.58 32.80 32.60 36.80 EXCB14 0.11 0.91 0.90 1.1 0.11 6 7.2 0.78 5.40 53 18 0.009 10.22 5.79 4.82 32.70 32.20 36.90 EXDMH3 0.91 5.40 55 18 0.005 7.77 4.40 2.37 32.20 31.90 36.90 O/G 4.26 21.62 10 24 0.040 45.33 14.44 23.72 32.00 31.60 36.90 DMH5 4.26 21.62 157 24 0.010 22.67 7.22 1.05 31.40 29.83 37.00 FES 21.62 81 36 0.009 62.58 8.86 40.96 29.71 29.00 40.00 EXCB8 225 White's Path - STORM SEWER DESIGN TRIBUTARY AREA TIME OF FLOW CB1 DRAINAGE STRUCTURE EXCB1 EXCB2 EXCB4 EXCB5 DMH2 DMH1 CB2 EXDMH1 TRENCH CB4 CB3 CB5 DMH3 CB7 EXCB6 EXCB3 CDS DMH4 CB6 EXCB7 EXDMH2 EXCB9 EXCB10 EXCB11 DMH5 EXCB12 EXCB13 EXCB14 EXDMH3 O/G Designed By:Checked By: Drawing No.: Issue Date: Designed By: Drawn By: Project No:Scale: 072846 KK/SA MT/MD KK 04/28/2022 1" = 50' 2S/4S 2S/4S CB1 CB1 CB2 CB2 CB3 CB3 CB4 CB4 CB5 CB5 CB6 CB6 CB7 CB7 5P Proposed Retention/Recharge Basin CDS CB CDS DMH1 CB DMH1 DMH2 CB EXDMH3 DMH3 CB EXDMH3 DMH4 CB EXDMH3 MH5 CB DMH5 PCB1 CB CB1 PCB2 CB CB2 PCB3 CB CB3 PCB4 CB PCB4 PCB5 CB CB5 PCB6 CB CB6 PCB7 CB CB7 Routing Diagram for 225 White's Path Yarmouth Proposed - Tailwater 25-Year Prepared by CHA Companies, Inc., Printed 6/15/2022 HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link 225 White's Path - Postdevelopment Hydrology 25-year Tailwater 225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 2HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 2.007 49 50-75% Grass cover, Fair, HSG A (2S/4S, CB1, CB2, CB3, CB4, CB5, CB6, CB7) 4.135 98 Paved parking, HSG A (2S/4S, CB1, CB2, CB3, CB4, CB5, CB6, CB7) 0.013 98 Roofs, HSG A (2S/4S) 0.410 98 Water Surface, HSG A (2S/4S) 0.667 30 Woods, Good, HSG A (2S/4S, CB2, CB4) 7.233 78 TOTAL AREA 225 White's Path - Postdevelopment Hydrology 25-year Tailwater 225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 3HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 7.233 HSG A 2S/4S, CB1, CB2, CB3, CB4, CB5, CB6, CB7 0.000 HSG B 0.000 HSG C 0.000 HSG D 0.000 Other 7.233 TOTAL AREA 225 White's Path - Postdevelopment Hydrology 25-year Tailwater 225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 4HydroCAD® 10.10-6a s/n 01012 © 2020 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 2.007 0.000 0.000 0.000 0.000 2.007 50-75% Grass cover, Fair 2S/4S, CB1, CB2, CB3, CB4, CB5, CB6, CB7 4.135 0.000 0.000 0.000 0.000 4.135 Paved parking 2S/4S, CB1, CB2, CB3, CB4, CB5, CB6, CB7 0.013 0.000 0.000 0.000 0.000 0.013 Roofs 2S/4S 0.410 0.000 0.000 0.000 0.000 0.410 Water Surface 2S/4S 0.667 0.000 0.000 0.000 0.000 0.667 Woods, Good 2S/4S, CB2, CB4 7.233 0.000 0.000 0.000 0.000 7.233 TOTAL AREA 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 5HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Sim-Route method - Pond routing by Sim-Route method Runoff Area=238,906 sf 66.26% Impervious Runoff Depth=3.62"Subcatchment 2S/4S: 2S/4S Flow Length=782' Tc=6.3 min CN=80 Runoff=22.97 cfs 1.654 af Runoff Area=4,476 sf 77.08% Impervious Runoff Depth=4.35"Subcatchment CB1: CB1 Tc=5.0 min CN=87 Runoff=0.53 cfs 0.037 af Runoff Area=7,964 sf 43.23% Impervious Runoff Depth=1.80"Subcatchment CB2: CB2 Tc=5.0 min CN=60 Runoff=0.38 cfs 0.027 af Runoff Area=5,487 sf 72.32% Impervious Runoff Depth=4.03"Subcatchment CB3: CB3 Tc=5.0 min CN=84 Runoff=0.61 cfs 0.042 af Runoff Area=6,721 sf 48.92% Impervious Runoff Depth=2.14"Subcatchment CB4: CB4 Tc=5.0 min CN=64 Runoff=0.39 cfs 0.027 af Runoff Area=23,633 sf 47.67% Impervious Runoff Depth=2.85"Subcatchment CB5: CB5 Tc=5.0 min CN=72 Runoff=1.87 cfs 0.129 af Runoff Area=9,923 sf 46.00% Impervious Runoff Depth=2.85"Subcatchment CB6: CB6 Tc=5.0 min CN=72 Runoff=0.79 cfs 0.054 af Runoff Area=17,948 sf 57.20% Impervious Runoff Depth=3.32"Subcatchment CB7: CB7 Tc=5.0 min CN=77 Runoff=1.66 cfs 0.114 af Peak Elev=35.54' Storage=43,086 cf Inflow=28.61 cfs 2.086 afPond 5P: Proposed Retention/Recharge Basin Outflow=2.45 cfs 2.094 af Peak Elev=35.54' Inflow=6.15 cfs 0.431 afPond CDS: CDS 24.0" Round Culvert n=0.013 L=14.0' S=0.0100 '/' Outflow=6.15 cfs 0.431 af Peak Elev=35.71' Inflow=0.90 cfs 0.065 afPond DMH1: DMH1 12.0" Round Culvert n=0.013 L=118.0' S=0.0050 '/' Outflow=0.90 cfs 0.065 af Peak Elev=35.55' Inflow=1.89 cfs 0.134 afPond DMH2: EXDMH3 15.0" Round Culvert n=0.013 L=91.0' S=0.0052 '/' Outflow=1.89 cfs 0.134 af Peak Elev=35.54' Inflow=3.75 cfs 0.263 afPond DMH3: EXDMH3 18.0" Round Culvert n=0.013 L=70.0' S=0.0047 '/' Outflow=3.75 cfs 0.263 af Peak Elev=35.54' Inflow=6.15 cfs 0.431 afPond DMH4: EXDMH3 24.0" Round Culvert n=0.013 L=60.0' S=0.0050 '/' Outflow=6.15 cfs 0.431 af Peak Elev=35.54' Inflow=6.15 cfs 0.431 afPond MH5: DMH5 36.0" Round Culvert n=0.013 L=81.0' S=0.0088 '/' Outflow=6.15 cfs 0.432 af Peak Elev=35.90' Inflow=0.53 cfs 0.037 afPond PCB1: CB1 12.0" Round Culvert n=0.013 L=55.0' S=0.0053 '/' Outflow=0.53 cfs 0.037 af 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 6HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Peak Elev=35.86' Inflow=0.38 cfs 0.027 afPond PCB2: CB2 12.0" Round Culvert n=0.013 L=58.0' S=0.0050 '/' Outflow=0.38 cfs 0.027 af Peak Elev=36.00' Inflow=0.61 cfs 0.042 afPond PCB3: CB3 12.0" Round Culvert n=0.013 L=38.0' S=0.0108 '/' Outflow=0.61 cfs 0.042 af Peak Elev=36.11' Inflow=0.39 cfs 0.027 afPond PCB4: PCB4 12.0" Round Culvert n=0.013 L=41.0' S=0.0161 '/' Outflow=0.39 cfs 0.027 af Peak Elev=36.17' Inflow=1.87 cfs 0.129 afPond PCB5: CB5 12.0" Round Culvert n=0.013 L=65.0' S=0.0098 '/' Outflow=1.87 cfs 0.129 af Peak Elev=35.80' Inflow=0.79 cfs 0.054 afPond PCB6: CB6 12.0" Round Culvert n=0.013 L=5.0' S=0.0200 '/' Outflow=0.79 cfs 0.054 af Peak Elev=36.60' Inflow=1.66 cfs 0.114 afPond PCB7: CB7 12.0" Round Culvert n=0.013 L=74.0' S=0.0099 '/' Outflow=1.66 cfs 0.114 af Total Runoff Area = 7.233 ac Runoff Volume = 2.085 af Average Runoff Depth = 3.46" 36.98% Pervious = 2.675 ac 63.02% Impervious = 4.558 ac 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 7HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S/4S: 2S/4S Runoff =22.97 cfs @ 12.09 hrs, Volume=1.654 af, Depth= 3.62" Routed to Pond 5P : Proposed Retention/Recharge Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 139,887 98 Paved parking, HSG A 17,873 98 Water Surface, HSG A 59,146 49 50-75% Grass cover, Fair, HSG A 21,454 30 Woods, Good, HSG A 546 98 Roofs, HSG A 238,906 80 Weighted Average 80,600 33.74% Pervious Area 158,306 66.26% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.5 37 0.0819 0.25 Sheet Flow, AB Grass: Short n= 0.150 P2= 3.35" 1.6 134 0.0075 1.39 Shallow Concentrated Flow, BC Unpaved Kv= 16.1 fps 0.5 109 0.0296 3.49 Shallow Concentrated Flow, CD Paved Kv= 20.3 fps 0.1 21 0.0200 6.95 5.46 Pipe Channel, DE 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.3 50 0.0040 3.11 2.44 Pipe Channel, EF 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.2 62 0.0180 6.59 5.18 Pipe Channel, FG 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 Corrugated PP, smooth interior 0.8 259 0.0160 5.74 4.51 Pipe Channel, GH 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.1 20 0.0160 5.74 4.51 Pipe Channel, HI 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 0.2 90 0.0100 9.44 66.70 Pipe Channel, IJ 36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75' n= 0.013 Corrugated PE, smooth interior 6.3 782 Total 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 8HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment CB1: CB1 Runoff =0.53 cfs @ 12.07 hrs, Volume=0.037 af, Depth= 4.35" Routed to Pond PCB1 : CB1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 3,450 98 Paved parking, HSG A 1,026 49 50-75% Grass cover, Fair, HSG A 0 30 Woods, Good, HSG A 4,476 87 Weighted Average 1,026 22.92% Pervious Area 3,450 77.08% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Summary for Subcatchment CB2: CB2 Runoff =0.38 cfs @ 12.08 hrs, Volume=0.027 af, Depth= 1.80" Routed to Pond PCB2 : CB2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 3,443 98 Paved parking, HSG A 174 49 50-75% Grass cover, Fair, HSG A 4,347 30 Woods, Good, HSG A 7,964 60 Weighted Average 4,521 56.77% Pervious Area 3,443 43.23% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Summary for Subcatchment CB3: CB3 Runoff =0.61 cfs @ 12.07 hrs, Volume=0.042 af, Depth= 4.03" Routed to Pond PCB3 : CB3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 9HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Area (sf) CN Description 3,968 98 Paved parking, HSG A 1,519 49 50-75% Grass cover, Fair, HSG A 0 30 Woods, Good, HSG A 5,487 84 Weighted Average 1,519 27.68% Pervious Area 3,968 72.32% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Summary for Subcatchment CB4: CB4 Runoff =0.39 cfs @ 12.08 hrs, Volume=0.027 af, Depth= 2.14" Routed to Pond PCB4 : PCB4 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 3,288 98 Paved parking, HSG A 175 49 50-75% Grass cover, Fair, HSG A 3,258 30 Woods, Good, HSG A 6,721 64 Weighted Average 3,433 51.08% Pervious Area 3,288 48.92% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Summary for Subcatchment CB5: CB5 Runoff =1.87 cfs @ 12.08 hrs, Volume=0.129 af, Depth= 2.85" Routed to Pond PCB5 : CB5 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 11,266 98 Paved parking, HSG A 12,367 49 50-75% Grass cover, Fair, HSG A 0 30 Woods, Good, HSG A 23,633 72 Weighted Average 12,367 52.33% Pervious Area 11,266 47.67% Impervious Area 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 10HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Summary for Subcatchment CB6: CB6 Runoff =0.79 cfs @ 12.08 hrs, Volume=0.054 af, Depth= 2.85" Routed to Pond PCB6 : CB6 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 4,565 98 Paved parking, HSG A 5,358 49 50-75% Grass cover, Fair, HSG A 0 30 Woods, Good, HSG A 9,923 72 Weighted Average 5,358 54.00% Pervious Area 4,565 46.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, Summary for Subcatchment CB7: CB7 Runoff =1.66 cfs @ 12.07 hrs, Volume=0.114 af, Depth= 3.32" Routed to Pond PCB7 : CB7 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.82" Area (sf) CN Description 10,267 98 Paved parking, HSG A 7,681 49 50-75% Grass cover, Fair, HSG A 0 30 Woods, Good, HSG A 17,948 77 Weighted Average 7,681 42.80% Pervious Area 10,267 57.20% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 5.0 Direct Entry, 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 11HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond 5P: Proposed Retention/Recharge Basin Inflow Area =7.233 ac, 63.02% Impervious, Inflow Depth = 3.46" for 25-year event Inflow =28.61 cfs @ 12.10 hrs, Volume=2.086 af Outflow =2.45 cfs @ 13.23 hrs, Volume=2.094 af, Atten= 91%, Lag= 67.9 min Discarded =2.45 cfs @ 13.23 hrs, Volume=2.094 af Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.54' @ 13.23 hrs Surf.Area= 12,777 sf Storage= 43,086 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 210.9 min ( 1,029.9 - 818.9 ) Volume Invert Avail.Storage Storage Description #1 29.00'109,951 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim.Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(feet)(cubic-feet)(cubic-feet)(sq-ft) 29.00 432 207.0 0 0 432 30.00 2,599 554.0 1,364 1,364 21,449 31.00 4,308 577.0 3,418 4,781 23,595 32.00 6,073 597.0 5,165 9,947 25,554 33.00 7,900 618.0 6,967 16,913 27,673 34.00 9,781 637.0 8,824 25,737 29,672 35.00 11,720 656.0 10,736 36,473 31,731 36.00 13,714 674.0 12,704 49,177 33,749 37.00 15,765 693.0 14,728 63,904 35,925 38.00 17,873 712.0 16,808 80,712 38,163 39.00 20,038 731.0 18,945 99,657 40,461 39.50 21,142 740.0 10,294 109,951 41,577 Device Routing Invert Outlet Devices #1 Discarded 29.00'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=2.45 cfs @ 13.23 hrs HW=35.54' (Free Discharge) 1=Exfiltration (Exfiltration Controls 2.45 cfs) Summary for Pond CDS: CDS Inflow Area =1.748 ac, 52.85% Impervious, Inflow Depth = 2.96" for 25-year event Inflow =6.15 cfs @ 12.11 hrs, Volume=0.431 af Outflow =6.15 cfs @ 12.12 hrs, Volume=0.431 af, Atten= 0%, Lag= 0.6 min Primary =6.15 cfs @ 12.12 hrs, Volume=0.431 af Routed to Pond MH5 : DMH5 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.54' @ 13.25 hrs Flood Elev= 36.90' 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 12HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Device Routing Invert Outlet Devices #1 Primary 32.87'24.0" Round Culvert L= 14.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 32.87' / 32.73' S= 0.0100 '/' Cc= 0.900 n= 0.013, Flow Area= 3.14 sf Primary OutFlow Max=6.14 cfs @ 12.12 hrs HW=34.14' TW=33.64' (Dynamic Tailwater) 1=Culvert (Barrel Controls 6.14 cfs @ 4.18 fps) Summary for Pond DMH1: DMH1 Inflow Area =0.286 ac, 55.41% Impervious, Inflow Depth = 2.72" for 25-year event Inflow =0.90 cfs @ 12.09 hrs, Volume=0.065 af Outflow =0.90 cfs @ 12.10 hrs, Volume=0.065 af, Atten= 0%, Lag= 0.6 min Primary =0.90 cfs @ 12.10 hrs, Volume=0.065 af Routed to Pond DMH2 : EXDMH3 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.71' @ 12.11 hrs Flood Elev= 36.90' Device Routing Invert Outlet Devices #1 Primary 35.01'12.0" Round Culvert L= 118.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 35.01' / 34.42' S= 0.0050 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Primary OutFlow Max=0.87 cfs @ 12.10 hrs HW=35.70' TW=35.35' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.87 cfs @ 2.11 fps) Summary for Pond DMH2: EXDMH3 Inflow Area =0.566 ac, 57.40% Impervious, Inflow Depth = 2.85" for 25-year event Inflow =1.89 cfs @ 12.09 hrs, Volume=0.134 af Outflow =1.89 cfs @ 12.10 hrs, Volume=0.134 af, Atten= 0%, Lag= 0.6 min Primary =1.89 cfs @ 12.10 hrs, Volume=0.134 af Routed to Pond DMH3 : EXDMH3 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.55' @ 13.27 hrs Flood Elev= 36.90' Device Routing Invert Outlet Devices #1 Primary 34.32'15.0" Round Culvert L= 91.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 34.32' / 33.85' S= 0.0052 '/' Cc= 0.900 n= 0.013, Flow Area= 1.23 sf Primary OutFlow Max=1.82 cfs @ 12.10 hrs HW=35.36' TW=35.09' (Dynamic Tailwater) 1=Culvert (Outlet Controls 1.82 cfs @ 2.27 fps) 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 13HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond DMH3: EXDMH3 Inflow Area =1.108 ac, 52.64% Impervious, Inflow Depth = 2.85" for 25-year event Inflow =3.75 cfs @ 12.09 hrs, Volume=0.263 af Outflow =3.75 cfs @ 12.10 hrs, Volume=0.263 af, Atten= 0%, Lag= 0.6 min Primary =3.75 cfs @ 12.10 hrs, Volume=0.263 af Routed to Pond DMH4 : EXDMH3 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.54' @ 13.26 hrs Flood Elev= 36.90' Device Routing Invert Outlet Devices #1 Primary 33.85'18.0" Round Culvert L= 70.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 33.85' / 33.52' S= 0.0047 '/' Cc= 0.900 n= 0.013, Flow Area= 1.77 sf Primary OutFlow Max=3.65 cfs @ 12.10 hrs HW=35.10' TW=34.70' (Dynamic Tailwater) 1=Culvert (Outlet Controls 3.65 cfs @ 3.15 fps) Summary for Pond DMH4: EXDMH3 Inflow Area =1.748 ac, 52.85% Impervious, Inflow Depth = 2.96" for 25-year event Inflow =6.15 cfs @ 12.10 hrs, Volume=0.431 af Outflow =6.15 cfs @ 12.11 hrs, Volume=0.431 af, Atten= 0%, Lag= 0.6 min Primary =6.15 cfs @ 12.11 hrs, Volume=0.431 af Routed to Pond CDS : CDS Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.54' @ 13.26 hrs Flood Elev= 36.90' Device Routing Invert Outlet Devices #1 Primary 33.42'24.0" Round Culvert L= 60.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 33.42' / 33.12' S= 0.0050 '/' Cc= 0.900 n= 0.013, Flow Area= 3.14 sf Primary OutFlow Max=6.04 cfs @ 12.11 hrs HW=34.70' TW=34.13' (Dynamic Tailwater) 1=Culvert (Outlet Controls 6.04 cfs @ 4.04 fps) Summary for Pond MH5: DMH5 Inflow Area =1.748 ac, 52.85% Impervious, Inflow Depth = 2.96" for 25-year event Inflow =6.15 cfs @ 12.12 hrs, Volume=0.431 af Outflow =6.15 cfs @ 12.13 hrs, Volume=0.432 af, Atten= 0%, Lag= 0.6 min Primary =6.15 cfs @ 12.13 hrs, Volume=0.432 af Routed to Pond 5P : Proposed Retention/Recharge Basin 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 14HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.54' @ 13.24 hrs Flood Elev= 40.00' Device Routing Invert Outlet Devices #1 Primary 29.71'36.0" Round Culvert L= 81.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 29.71' / 29.00' S= 0.0088 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 7.07 sf Primary OutFlow Max=0.00 cfs @ 12.13 hrs HW=33.75' TW=33.82' (Dynamic Tailwater) 1=Culvert ( Controls 0.00 cfs) Summary for Pond PCB1: CB1 Inflow Area =0.103 ac, 77.08% Impervious, Inflow Depth = 4.35" for 25-year event Inflow =0.53 cfs @ 12.07 hrs, Volume=0.037 af Outflow =0.53 cfs @ 12.08 hrs, Volume=0.037 af, Atten= 0%, Lag= 0.6 min Primary =0.53 cfs @ 12.08 hrs, Volume=0.037 af Routed to Pond DMH1 : DMH1 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.90' @ 12.10 hrs Flood Elev= 38.90' Device Routing Invert Outlet Devices #1 Primary 35.40'12.0" Round Culvert L= 55.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 35.40' / 35.11' S= 0.0053 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Primary OutFlow Max=0.50 cfs @ 12.08 hrs HW=35.89' TW=35.68' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.50 cfs @ 1.90 fps) Summary for Pond PCB2: CB2 Inflow Area =0.183 ac, 43.23% Impervious, Inflow Depth = 1.80" for 25-year event Inflow =0.38 cfs @ 12.08 hrs, Volume=0.027 af Outflow =0.38 cfs @ 12.09 hrs, Volume=0.027 af, Atten= 0%, Lag= 0.6 min Primary =0.38 cfs @ 12.09 hrs, Volume=0.027 af Routed to Pond DMH1 : DMH1 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.86' @ 12.11 hrs Flood Elev= 38.90' Device Routing Invert Outlet Devices #1 Primary 35.40'12.0" Round Culvert L= 58.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 35.40' / 35.11' S= 0.0050 '/' Cc= 0.900 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 15HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC n= 0.013, Flow Area= 0.79 sf Primary OutFlow Max=0.35 cfs @ 12.09 hrs HW=35.85' TW=35.70' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.35 cfs @ 1.53 fps) Summary for Pond PCB3: CB3 Inflow Area =0.126 ac, 72.32% Impervious, Inflow Depth = 4.03" for 25-year event Inflow =0.61 cfs @ 12.07 hrs, Volume=0.042 af Outflow =0.61 cfs @ 12.08 hrs, Volume=0.042 af, Atten= 0%, Lag= 0.6 min Primary =0.61 cfs @ 12.08 hrs, Volume=0.042 af Routed to Pond DMH2 : EXDMH3 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 36.00' @ 12.08 hrs Flood Elev= 39.10' Device Routing Invert Outlet Devices #1 Primary 35.60'12.0" Round Culvert L= 38.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 35.60' / 35.19' S= 0.0108 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Primary OutFlow Max=0.61 cfs @ 12.08 hrs HW=36.00' TW=35.31' (Dynamic Tailwater) 1=Culvert (Barrel Controls 0.61 cfs @ 3.07 fps) Summary for Pond PCB4: PCB4 Inflow Area =0.154 ac, 48.92% Impervious, Inflow Depth = 2.14" for 25-year event Inflow =0.39 cfs @ 12.08 hrs, Volume=0.027 af Outflow =0.39 cfs @ 12.09 hrs, Volume=0.027 af, Atten= 0%, Lag= 0.6 min Primary =0.39 cfs @ 12.09 hrs, Volume=0.027 af Routed to Pond DMH2 : EXDMH3 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 36.11' @ 12.09 hrs Flood Elev= 39.30' Device Routing Invert Outlet Devices #1 Primary 35.80'12.0" Round Culvert L= 41.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 35.80' / 35.14' S= 0.0161 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Primary OutFlow Max=0.39 cfs @ 12.09 hrs HW=36.11' TW=35.33' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.39 cfs @ 1.89 fps) 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 16HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Summary for Pond PCB5: CB5 Inflow Area =0.543 ac, 47.67% Impervious, Inflow Depth = 2.85" for 25-year event Inflow =1.87 cfs @ 12.08 hrs, Volume=0.129 af Outflow =1.87 cfs @ 12.09 hrs, Volume=0.129 af, Atten= 0%, Lag= 0.6 min Primary =1.87 cfs @ 12.09 hrs, Volume=0.129 af Routed to Pond DMH3 : EXDMH3 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 36.17' @ 12.09 hrs Flood Elev= 38.90' Device Routing Invert Outlet Devices #1 Primary 35.40'12.0" Round Culvert L= 65.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 35.40' / 34.76' S= 0.0098 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Primary OutFlow Max=1.87 cfs @ 12.09 hrs HW=36.16' TW=35.06' (Dynamic Tailwater) 1=Culvert (Barrel Controls 1.87 cfs @ 4.01 fps) Summary for Pond PCB6: CB6 Inflow Area =0.228 ac, 46.00% Impervious, Inflow Depth = 2.85" for 25-year event Inflow =0.79 cfs @ 12.08 hrs, Volume=0.054 af Outflow =0.79 cfs @ 12.09 hrs, Volume=0.054 af, Atten= 0%, Lag= 0.6 min Primary =0.79 cfs @ 12.09 hrs, Volume=0.054 af Routed to Pond DMH4 : EXDMH3 Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 35.80' @ 12.09 hrs Flood Elev= 38.80' Device Routing Invert Outlet Devices #1 Primary 35.30'12.0" Round Culvert L= 5.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 35.30' / 35.20' S= 0.0200 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Primary OutFlow Max=0.78 cfs @ 12.09 hrs HW=35.80' TW=34.66' (Dynamic Tailwater) 1=Culvert (Barrel Controls 0.78 cfs @ 2.92 fps) Summary for Pond PCB7: CB7 Inflow Area =0.412 ac, 57.20% Impervious, Inflow Depth = 3.32" for 25-year event Inflow =1.66 cfs @ 12.07 hrs, Volume=0.114 af Outflow =1.66 cfs @ 12.08 hrs, Volume=0.114 af, Atten= 0%, Lag= 0.6 min Primary =1.66 cfs @ 12.08 hrs, Volume=0.114 af Routed to Pond DMH4 : EXDMH3 225 White's Path - Postdevelopment Hydrology 25-year Tailwater Type III 24-hr 25-year Rainfall=5.82"225 White's Path Yarmouth Proposed - Tailwater 25-Year Printed 6/15/2022Prepared by CHA Companies, Inc. Page 17HydroCAD® 10.10-6a s/n 01012 © 2020 HydroCAD Software Solutions LLC Routing by Sim-Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 36.60' @ 12.08 hrs Flood Elev= 39.40' Device Routing Invert Outlet Devices #1 Primary 35.90'12.0" Round Culvert L= 74.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 35.90' / 35.17' S= 0.0099 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Primary OutFlow Max=1.66 cfs @ 12.08 hrs HW=36.60' TW=34.66' (Dynamic Tailwater) 1=Culvert (Barrel Controls 1.66 cfs @ 3.96 fps) Section 3.3 Drainage Area Plans 1S 2S 3S 4S 5S 6S 7S DP6DP4 DP2 DP3 DP1 DP5 DP7 Designed By:Checked By: Drawing No.: Issue Date: Designed By: Drawn By: Project No:Scale: 072846 KK/SA MT/MD KK 10/14/2021 1" = 50'DP1 1S 3S 5S 7S DP2/4 6S DP3 DP5 Designed By:Checked By: Drawing No.: Issue Date: Designed By: Drawn By: Project No:Scale: 072846 KK/SA MT/MD KK 02/18/2022 1" = 50'DP1 Section 4.0 Stormwater Management Calculations Section 4.1 Water Quality WATER QUALITY The water quality volume has been calculated based on 1” of rainfall over the net new impervious area. The calculation is shown below. Existing Impervious = 314,738 sq. ft.= 7.225 ac. Proposed Impervious = 347,835 sq. ft = 7.990 ac Net New Impervious On-Site = 33,097 sq. ft.= 0.760 ac. WQV (Water Quality Volume) based on 1-inch rainfall event Required WQV = (1”/12”) ft. x (33,097) sq. ft. = 2,758 cu. ft. The Contech CDS2025 treatment unit is sized based on flow capacity not volume per MassDEP’s requirements for flow through devices. The calculations that follow convert the runoff volume to a 1.0” Equivalent Water Quality Flow rate. See the document that follows with the flows and the proposed treatment units. Discharge Point Structure Tributary Area Tributary Area % Impervious CN Value WQV Tc qu WQF = qu A Q Unit Unit's Max Capacity (acres)(sq miles)(Estimated) (Watershed Inches)(min) (csm/in)(cfs)(cfs) 1.00 6 774 2.26 2025-5 3.20 Sizing using the equivalent water quality flow from 1.0" rainfall depth Water Quality Unit CDS2025-5 1.87 0.0029 53%75 Section 4.2 Total Suspended Solids (TSS) Removal Calculations INSTRUCTIONS:Non-automated: Mar. 4, 2008 1. Sheet is nonautomated. Print sheet and complete using hand calculations. Column A and B: See MassDEP Structural BMP Table 2. The calculations must be completed using the Column Headings specified in Chart and Not the Excel Column Headings 3. To complete Chart Column D, multiple Column B value within Row x Column C value within Row 4. To complete Chart Column E value, subtract Column D value within Row from Column C within Row 5. Total TSS Removal = Sum All Values in Column D Location: A B C D E TSS Removal Starting TSS Amount Remaining BMP1 Rate1 Load*Removed (B*C)Load (C-D) Catch basin 0.25 1.00 0.25 0.75 CDS Water Quality Unit 0.50 0.75 0.38 0.38 Retention/Recharge Basin 0.80 0.38 0.30 0.08 Total TSS Removal =93% Project:225 White's Path Prepared By:SFA *Equals remaining load from previous BMP (E) Date:4/23/2022 which enters the BMP 225 White's Path Yarmouth, MA TSS RemovalCalculationWorksheet INSTRUCTIONS:Non-automated: Mar. 4, 2008 1. Sheet is nonautomated. Print sheet and complete using hand calculations. Column A and B: See MassDEP Structural BMP Table 2. The calculations must be completed using the Column Headings specified in Chart and Not the Excel Column Headings 3. To complete Chart Column D, multiple Column B value within Row x Column C value within Row 4. To complete Chart Column E value, subtract Column D value within Row from Column C within Row 5. Total TSS Removal = Sum All Values in Column D Location: A B C D E TSS Removal Starting TSS Amount Remaining BMP1 Rate1 Load*Removed (B*C)Load (C-D) Catch basin 0.25 1.00 0.25 0.75 Oil/Grit Separator 0.25 0.75 0.19 0.56 Retention/Recharge Basin 0.80 0.56 0.45 0.11 Total TSS Removal =89% Project:225 White's Path Prepared By:SFA *Equals remaining load from previous BMP (E) Date:4/23/2022 which enters the BMP 225 White's Path Yarmouth, MA TSS RemovalCalculationWorksheet 1 KIM GUADAGNO Lt. Governor March 21, 2017 Derek M. Berg Contech Engineered Solutions, LLC 71 US Route 1, Suite F Scarborough, ME 04074 Re: Revised MTD Lab Certification Continuous Deflective Separator (CDS®) Stormwater Treatment Device by Contech Engineered Solutions, LLC On-line Installation TSS Removal Rate 50% Dear Mr. Berg: This revised certification letter supersedes the Department’s prior certification dated January 9, 2015. This revision was completed to reflect the updated Manufactured Treatment Device (MTD) scaling methodology as agreed upon by the manufacturers’ working group on September 19, 2016. In part, the updated scaling for hydrodynamic MTDs is based on the depth of the reference (tested) MTD from the top of the false floor utilized during removal efficiency testing, not from the physical bottom of the unit. Based on the above decision, Table A-2 of the NJCAT Technology Verification report located at http://www.njcat.org/uploads/newDocs/CDSVerificationReportFinal1.pdf has been revised, and Table 1 noted below has been added. The Stormwater Management rules under N.J.A.C. 7:8-5.5(b) and 5.7 (c) allow the use of manufactured treatment devices (MTDs) for compliance with the design and performance standards at N.J.A.C. 7:8-5 if the pollutant removal rates have been verified by the New Jersey Corporation for Advanced Technology (NJCAT) and have been certified by the New Jersey Department of Environmental Protection (NJDEP). Contech Engineered Solutions, LLC has requested an MTD Laboratory Certification for the CDS® Stormwater Treatment Device. The verification is subject to the “Procedure for Obtaining Verification of a Stormwater Manufactured Treatment Device from New Jersey Corporation for Advance Technology” dated January 25, 2013. The applicable protocol is the “New Jersey Laboratory Testing Protocol to Assess Total Suspended Solids Removal by a Hydrodynamic Sedimentation Manufactured Treatment Device” dated January 25, 2013. NJCAT verification documents submitted to the NJDEP indicate that the requirements of the aforementioned protocol have been met or exceeded. The NJCAT letter also included a recommended certification TSS removal rate and the required maintenance plan. The NJCAT Verification Report with the Verification DEPARTMENT OF ENVIRONMENTAL PROTECTION CHRIS CHRISTIE BOB MARTIN Governor Commissioner New Jersey is an Equal Opportunity Employer Printed on Recycled Paper and Recyclable Bureau of Nonpoint Pollution Control Division of Water Quality 401-02B Post Office Box 420 Trenton, New Jersey 08625-0420 609-633-7021 Fax: 609-777-0432 http://www.state.nj.us/dep/dwq/bnpc_home.htm 2 Appendix dated September 2014 (Revised January 2017) for this device is published online at http://www.njcat.org/verification-process/technology-verification-database.html. The NJDEP certifies the use of the CDS® Stormwater Treatment Device by Contech Engineered Solutions, LLC at a TSS removal rate of 50% when designed, operated, and maintained in accordance with the information provided in the Verification Appendix and the following conditions: 1. The maximum treatment flow rate (MTFR) for the manufactured treatment device (MTD) is calculated using the New Jersey Water Quality Design Storm (1.25 inches in 2 hrs) in N.J.A.C. 7:8-5.5. 2. The CDS® Stormwater Treatment Device shall be installed using the same configuration reviewed by NJCAT and shall be sized in accordance with the criteria specified in item 6 below. 3. This CDS® Stormwater Treatment Device cannot be used in series with another MTD or a media filter (such as a sand filter) to achieve an enhanced removal rate for total suspended solids (TSS) removal under N.J.A.C. 7:8-5.5. 4. Additional design criteria for MTDs can be found in Chapter 9.6 of the New Jersey Stormwater Best Management Practices (NJ Stormwater BMP) Manual which can be found on-line at www.njstormwater.org. 5. The maintenance plan for a site using this device shall incorporate, at a minimum, the maintenance requirements for the CDS® Stormwater Treatment Device. A copy of the maintenance plan is attached to this certification. However, it is recommended to review the maintenance website at http://www.conteches.com/products/stormwater-management/treatment/cds.aspx#1822141- technical-info for any changes to the maintenance requirements. 6. Sizing Requirements: The example below demonstrates the sizing procedure for the CDS®: Example: A 0.25-acre impervious site is to be treated to 50% TSS removal using a CDS®. The impervious site runoff (Q) based on the New Jersey Water Quality Design Storm was determined to be 0.79 cfs. Maximum Treatment Flow Rate (MTFR) Evaluation: The site runoff (Q) was based on the following: time of concentration = 10 minutes i=3.2 in/hr (page 5-8, Fig. 5-3 of the NJ Stormwater BMP Manual) c=0.99 (runoff coefficient for impervious) Q=ciA=0.99x3.2x0.25=0.79 cfs Given the site runoff is 0.79 cfs and based on Table 1 below, the CDS® Model CDS-4 with an MTFR of 0.93 cfs would be the smallest model approved that could be used for this site that could remove 50% of the TSS from the impervious area without exceeding the MTFR. 3 The sizing table corresponding to the available system models is noted below. Additional specifications regarding each model can be found in the Verification Appendix under Table A-1 and A-2. Table 1 CDS Models CDS Model Manhole Diameter (ft.) Treatment Chamber Depth (ft.) MTFR (cfs) CDS-3 3 3.50 0.52 CDS-4 4 3.50 0.93 CDS-5 5 3.75 1.5 CDS-6 6 4.50 2.1 CDS-7 7 5.25 2.8 CDS-8 8 6.00 3.7 CDS-10 10 7.50 5.8 CDS-12 12 9.00 8.4  Treatment Chamber Depth is defined as the depth below the invert to the top of the false floor installed at 50% sediment depth. A detailed maintenance plan is mandatory for any project with a Stormwater BMP subject to the Stormwater Management Rules, N.J.A.C. 7:8. The plan must include all of the items identified in the Stormwater Management Rules, N.J.A.C. 7:8-5.8. Such items include, but are not limited to, the list of inspection and maintenance equipment and tools, specific corrective and preventative maintenance tasks, indication of problems in the system, and training of maintenance personnel. Additional information can be found in Chapter 8: Maintenance and Retrofit of Stormwater Management Measures. If you have any questions regarding the above information, please contact Mr. Shashi Nayak of my office at (609) 633-7021. Sincerely, James J. Murphy, Chief Bureau of Nonpoint Pollution Control Attachment: Maintenance Plan c: Chron File Richard Magee, NJCAT Vince Mazzei, NJDEP - DLUR Ravi Patraju, NJDEP - BES Gabriel Mahon, NJDEP - BNPC Shashi Nayak, NJDEP – BNPC CDS® Inspection and Maintenance Guide – New Jersey ENGINEERED SOLUTIONS Maintenance The CDS system should be inspected at regular intervals and maintained when necessary to ensure optimum performance. The rate at which the system collects pollutants will depend more heavily on site activities than the size of the unit. For example, unstable soils or heavy winter sanding will cause the grit chamber to fill more quickly but regular sweeping of paved surfaces will slow accumulation. Inspection Inspection is the key to effective maintenance and is easily performed. Pollutant transport and deposition may vary from year to year and regular inspections will help ensure that the system is cleaned out at the appropriate time. At a minimum, inspections should be performed twice per year (e.g. spring and fall) however more frequent inspections may be necessary in climates where winter sanding operations may lead to rapid accumulations, or in equipment washdown areas. Installations should also be inspected more frequently where excessive amounts of trash are expected. The visual inspection should ascertain that the system components are in working order and that there are no blockages or obstructions in the inlet and separation screen. The inspection should also quantify the accumulation of hydrocarbons, trash, and sediment in the system. Measuring pollutant accumulation can be done with a calibrated dipstick, tape measure or other measuring instrument. If absorbent material is used for enhanced removal of hydrocarbons, the level of discoloration of the sorbent material should also be identified during inspection. It is useful and often required as part of an operating permit to keep a record of each inspection. A simple form for doing so is provided. Access to the CDS unit is typically achieved through two manhole access covers. One opening allows for inspection and cleanout of the separation chamber (cylinder and screen) and isolated sump. The other allows for inspection and cleanout of sediment captured and retained outside the screen. For deep units, a single manhole access point allows both sump cleanout and access outside the screen. The CDS system should be cleaned when the level of sediment has reached 75% of capacity in the isolated sump or when an appreciable level of hydrocarbons and trash has accumulated. If absorbent material is used, it should be replaced when significant discoloration has occurred. Performance will not be impacted until 100% of the sump capacity is exceeded however it is recommended that the system be cleaned prior to that for easier removal of sediment. The level of sediment is easily determined by measuring from finished grade down to the top of the sediment pile. To avoid underestimating the level of sediment in the chamber, the measuring device must be lowered to the top of the sediment pile carefully. Particles at the top of the pile typically offer less resistance to the end of the rod than consolidated particles toward the bottom of the pile. Once this measurement is recorded, it should be compared to the as-built drawing for the unit to determine weather the height of the sediment pile off the bottom of the sump floor exceeds 75% of the total height of isolated sump. Refer to Table 1 for depth from water surface to top of sediment pile for each model size indicating that maintenance is required. Cleaning Cleaning of a CDS systems should be done during dry weather conditions when no flow is entering the system. The use of a vacuum truck is generally the most effective and convenient method of removing pollutants from the system. Simply remove the manhole covers and insert the vacuum hose into the sump. The system should be completely drained down and the sump fully evacuated of sediment. The area outside the screen should also be cleaned out if pollutant build-up exists in this area. In installations where the risk of petroleum spills is small, liquid contaminants may not accumulate as quickly as sediment. However, the system should be cleaned out immediately in the event of an oil or gasoline spill should be cleaned out immediately. Motor oil and other hydrocarbons that accumulate on a more routine basis should be removed when an appreciable layer has been captured. To remove these pollutants, it may be preferable to use absorbent pads since they are usually less expensive to dispose than the oil/water emulsion that may be created by vacuuming the oily layer. Trash and debris can be netted out to separate it from the other pollutants. The screen should be power washed to ensure it is free of trash and debris. Manhole covers should be securely seated following cleaning activities to prevent leakage of runoff into the system from above and also to ensure that proper safety precautions have been followed. Confined space entry procedures need to be followed if physical access is required. Disposal of all material removed from the CDS system should be done in accordance with local regulations. In many jurisdictions, disposal of the sediments may be handled in the same manner as the disposal of sediments removed from catch basins or deep sump manholes. Table 1: CDS Maintenance Indicators and Sediment Storage Capacities 1 Distances from water surface to top of sediment pile are based on 75% of sump capacity being occupied. 800.925.5240 www.ContechES.com Support • Drawings and specifications are available at www.contechstormwater.com. • Site-specific design support is available from our engineers. ©2017 Contech Engineered Solutions LLC, a QUIKRETE Company Contech Engineered Solutions LLC provides site solutions for the civil engineering industry. Contech’s portfolio includes bridges, drainage, sanitary sewer, earth stabilization and stormwater treament products. For information, visit www.ContechES.com or call 800.338.1122 NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS A WARRANTY. APPLICATIONS SUGGESTED HEREIN ARE DESCRIBED ONLY TO HELP READERS MAKE THEIR OWN EVALUATIONS AND DECISIONS, AND ARE NEITHER GUARANTEES NOR WARRANTIES OF SUITABILITY FOR ANY APPLICATION. CONTECH MAKES NO WARRANTY WHATSOEVER, EXPRESS OR IMPLIED, RELATED TO THE APPLICATIONS, MATERIALS, COATINGS, OR PRODUCTS DISCUSSED HEREIN. ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE ARE DISCLAIMED BY CONTECH. SEE CONTECH’S CONDITIONS OF SALE (AVAILABLE AT WWW.CONTECHES.COM/COS) FOR MORE INFORMATION. The product(s) described may be protected by one or more of the following US patents: 5,322,629; 5,624,576; 5,707,527; 5,759,415; 5,788,848; 5,985,157; 6,027,639; 6,350,374; 6,406,218; 6,641,720; 6,511,595; 6,649,048; 6,991,114; 6,998,038; 7,186,058; 7,296,692; 7,297,266; 7,517,450 related foreign patents or other patents pending. CDS-Maintenance-NH 3/17 ENGINEERED SOLUTIONS CDS Model Diameter Distance from Water Surface to Top of Sediment Pile1 Sediment Storage Capacity ft m ft m yd3 m3 CDS-3 3 0.9 3.0 0.9 0.5 0.4 CDS-4 4 1.2 3.0 0.9 0.9 0.7 CDS-5 5 1.5 3.25 1.0 1.5 1.1 CDS-6 6 1.8 4.0 1.2 2.1 1.6 CDS-7 7 2.1 4.75 1.4 2.9 2.2 CDS-8 8 2.4 5.5 1.7 3.7 2.8 CDS-10 10 3.0 7.0 2.1 5.8 4.4 CDS-12 12 3.4 8.5 2.6 8.4 6.4 CDS Inspection & Maintenance Log CDS Model: Location: Water Floatable Describe Maintenance Date depth to Layer Maintenance Personnel Comments sediment1 Thickness2 Performed —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— 1. The water depth to sediment is determined by taking two measurements with a stadia rod: one measurement from the manhole opening to the top of the sediment pile and the other from the manhole opening to the water surface. If the difference between these measurements is less than the values listed in table 1 the system should be cleaned out. Note: to avoid underestimating the volume of sediment in the chamber, the measuring device must be carefully lowered to the top of the sediment pile. 2. For optimum performance, the system should be cleaned out when the floating hydrocarbon layer accumulates to an appreciable thickness. In the event of an oil spill, the system should be cleaned immediately. Get social with us: 800-338-1122 | www.ContechES.com NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS A WARRANTY. APPLICATIONS SUGGESTED HEREIN ARE DESCRIBED ONLY TO HELP READERS MAKE THEIR OWN EVALUATIONS AND DECISIONS, AND ARE NEITHER GUARANTEES NOR WARRANTIES OF SUITABILITY FOR ANY APPLICATION. CONTECH MAKES NO WARRANTY WHATSOEVER, EXPRESS OR IMPLIED, RELATED TO THE APPLICATIONS, MATERIALS, COATINGS, OR PRODUCTS DISCUSSED HEREIN. ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE ARE DISCLAIMED BY CONTECH. SEE CONTECH’S CONDITIONS OF SALE (AVAILABLE AT WWW.CONTECHES.COM/COS) FOR MORE INFORMATION. © 2020 Contech Engineered Solutions LLC, a QUIKRETE Company All Rights Reserved. Printed in the USA.) Revision 01/20 ENGINEERED SOLUTIONS STORMWATER SOLUTIONS PIPE SOLUTIONS STRUCTURES SOLUTIONS CASCADE Model Treatment Rate (cfs) Sediment Capacity1 (CF) CS-4 2.00 19 CS-5 3.50 29 CS-6 5.60 42 CS-8 12.00 75 CS-10 18.00 118 CDS Model Treatment Rate² (cfs) Sediment Capacity1 (CF) 1515-3 1.00 14 2015-4 1.40 25 2015-5 1.40 39 2015-6 1.40 57 2020-5 2.20 39 2020-6 2.20 57 2025-5 3.20 39 2025-6 3.20 57 3020-6 3.90 57 3025-6 5.00 57 3030-6 5.70 57 3035-6 6.50 57 4030-8 7.50 151 4040-8 9.50 151 VORTECHS Model Treatment Rate (cfs) Sediment Capacity3 (CF) 1000 1.60 16 2000 2.80 32 3000 4.50 49 4000 6.00 65 5000 8.50 86 7000 11.00 108 9000 14.00 130 11000 17.5 151 16000 25 192 STORMCEPTOR STC Model Treatment Rate (cfs) Sediment Capacity1 (CF) STC 450i 0.40 46 STC 900 0.89 89 STC 2400 1.58 205 STC 4800 2.47 543 STC 7200 3.56 839 STC 11000 4.94 1086 STC 16000 7.12 1677 1 Additional sediment storage capacity available – Check with your local representative for information. 2 Treatment Capacity is based on laboratory testing using OK-110 (average D50 particle size of approximately 100 microns) and a 2400 micron screen. 3 Maintenance recommended when sediment depth has accumulated to within 12-18 inches of the dry weather water surface elevation. Product Flow Rates Section 4.3 Required Recharge Volume RECHARGE The Required Recharge Volume is calculated using the equation in the 2008 Massachusetts Stormwater Handbook. The Required Recharge Volume equals a depth of runoff corresponding to the soil type multiplied by the new impervious areas covering that soil type at the post- development site. The Required Recharge Volume is based on the Static method. The project is a mix of new and redevelopment and subject to the Recharge Standard to the extent practicable. Soils on the site consist of soils from hydrologic soil group (HSG) “A” based on the U.S. Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS), Soil Survey of Plymouth County. Soils within the property are classified as: Urban Land which comprises much of the developed portion of the site and Carver coarse sand which comprises the remaining land area including the location of the proposed improvements. Test pits have been advanced at the site confirming the presence of coarse sands in the westerly portion of the site. The project has been designed to provide recharge via a retention/recharge (infiltration) basin BMP that will receive stormwater runoff collected through the use of a catch basins and trench drains. Roof runoff is collected via an existing, independent roof drain system that conveys roof runoff to subsurface infiltration structures. This system will not be altered. The following equation can be used to determine the Required Recharge Volume. Rv = F x impervious area (Equation 1) Volume 3, Ch 1, page 15 Rv = Required Recharge Volume, expressed in cubic feet, cubic yards, or acre-feet F = Target Depth Factor associated with each Hydrologic Soil Group (HSG) Impervious Area = pavement area less roof area F for A soils = 0.60 inches (Table 2.3.2) Volume 3, Ch 1, page 16 F for B soils = 0.35 inches F for C soils = 0.25 inches F for D soils = 0.10 inches Using the formula above, the following table shows the site’s proposed impervious surface area (does not include off-site impervious) and the calculated Required Recharge Volume. Existing Impervious = 314,738 sq. ft.= 7.225 ac. Proposed Impervious = 347,835 sq. ft = 7.990 ac Net New Impervious On-Site = 33,097 sq. ft.= 0.760 ac. Roof Area = 156,467 sq. ft.= 3.592 ac. Impervious Area = (347,835 sq. ft. – 156,467 sq. ft.) = 191, 368 sq. ft. or 4.393 ac. Required Recharge Volume Rv = (FA x impervious area)HSGA Rv = 0.6 in x (4.393 ac) x 1 ft/12 in Rv = 0.2197 ac-ft or 9,568 cu. ft. The entire runoff volume directed to the proposed retention/recharge basin will be retained and infiltrated. The basin has a capacity to store 109,951 cu. ft. or 2.524 ac-ft. Conclusion: Hence, the storage available within the proposed retention/recharge basin is greater than the Required Recharge Volume: 109,951 cu. ft. >> 9,568 cu. ft. The recharge volume provided by the proposed retention/recharge basin greatly exceeds the Required Recharge Volume for the impervious surface area proposed on the site. The project’s stormwater management system satisfies Standard 3 of the MassDEP Stormwater Regulations. Section 4.4 Drawdown Time Calculations DRAWDOWN TIME Below are the drawdown time calculations for the recharge systems proposed on the site. The calculation uses an estimated hydraulic conductivity value “K.” Soils on the site consist soils from hydrologic soil groups (HSG) “A” based on the U.S. Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS), Soil Survey of Plymouth County. Soils within the property are classified as: Urban Land which comprises much of the developed portion of the site and Carver coarse sand which comprises the remaining land area including the location of the proposed improvements. Test pits have been advanced at the site confirming the presence of coarse sands in the westerly portion of the site. A value of the hydraulic conductivity “K” of 8.27 inches per hour which corresponds to sand soils was selected for the basis of design. The formula below is the recommended method of calculating drawdown times from the Massachusetts Stormwater Management Handbook DRAWDOWN TIME CALCULATION ))((AreaBottomK RvTimedrawdown Where: Rv =Storage Volume K =Saturated Hydraulic Conductivity, Rawls Rate Bottom Area =Bottom Area of Recharge Structure See the following Drawdown Calculation table for infiltration rates, bottom area, and drawdown times. Drawdown Calculation Recharge BMP Infiltration Rate (in/hr) k Storage Volume (c.f.) Rv Bottom Area (s.f.) Draw Down Time (hrs.) Retention/Recharge Basin 8.27 62,144 2,5991 34.7 1Bottom Area taken as the area bounded by elevation contour 30 of the proposed retention/recharge basin. Conclusion: The calculations show that the drawdown times for the infiltration BMP is less than 72 hours, as required. Section 4.5 Illicit Discharge Statement ILLICIT DISCHARGE COMPLIANCE STATEMENT Standard 10: Massachusetts Stormwater Standards Handbook Illicit discharges are defined as discharges into waters of the State or municipal separate stormwater system (MS4) that are not entirely comprised of stormwater. Exclusions for non-stormwater discharges into drainage systems include activities or facilities for firefighting, water line flushing, landscape irrigation, uncontaminated groundwater discharge, potable water sources, foundation drains, air conditioning condensation, footing drains, individual resident car washing, water used to clean residential buildings without detergents, water used for street washing, and flows from riparian habitats/wetlands. These exclusions are subject to change and are under the discretion of the local governing authority. To the best of our knowledge and professional belief no illicit discharges to the stormwater system, surface waters, or wetland resource areas will remain on the site after construction. We will agree to implement a pollution prevention plan to prevent illicit discharges into the stormwater management system. The design of the site based on the plans prepared by CHA, 141 Longwater Drive, Suite104, Norwell, Massachusetts shows a separation and no direct connection between the stormwater management systems and the wastewater and/or groundwater on the site. To the maximum extent practicable, the design prevents entry of illicit discharges into the stormwater management system. Engineer’s Name: Kelly Killeen, P.E. (please print) Company: CHA Consulting, Inc. Section 5.0 Stormwater Checklist 5.1 225 Whites Path SW Checklist • 04/01/08 Stormwater Report Checklist • Page 1 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report A. Introduction Important: When filling out forms on the computer, use only the tab key to move your cursor - do not use the return key. A Stormwater Report must be submitted with the Notice of Intent permit application to document compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for the Stormwater Report (which should provide more substantive and detailed information) but is offered here as a tool to help the applicant organize their Stormwater Management documentation for their Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, the Stormwater Report must contain the engineering computations and supporting information set forth in Volume 3 of the Massachusetts Stormwater Handbook. The Stormwater Report must be prepared and certified by a Registered Professional Engineer (RPE) licensed in the Commonwealth. The Stormwater Report must include:  The Stormwater Checklist completed and stamped by a Registered Professional Engineer (see page 2) that certifies that the Stormwater Report contains all required submittals.1 This Checklist is to be used as the cover for the completed Stormwater Report.  Applicant/Project Name  Project Address  Name of Firm and Registered Professional Engineer that prepared the Report  Long-Term Pollution Prevention Plan required by Standards 4-6  Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan required by Standard 82  Operation and Maintenance Plan required by Standard 9 In addition to all plans and supporting information, the Stormwater Report must include a brief narrative describing stormwater management practices, including environmentally sensitive site design and LID techniques, along with a diagram depicting runoff through the proposed BMP treatment train. Plans are required to show existing and proposed conditions, identify all wetland resource areas, NRCS soil types, critical areas, Land Uses with Higher Potential Pollutant Loads (LUHPPL), and any areas on the site where infiltration rate is greater than 2.4 inches per hour. The Plans shall identify the drainage areas for both existing and proposed conditions at a scale that enables verification of supporting calculations. As noted in the Checklist, the Stormwater Management Report shall document compliance with each of the Stormwater Management Standards as provided in the Massachusetts Stormwater Handbook. The soils evaluation and calculations shall be done using the methodologies set forth in Volume 3 of the Massachusetts Stormwater Handbook. To ensure that the Stormwater Report is complete, applicants are required to fill in the Stormwater Report Checklist by checking the box to indicate that the specified information has been included in the Stormwater Report. If any of the information specified in the checklist has not been submitted, the applicant must provide an explanation. The completed Stormwater Report Checklist and Certification must be submitted with the Stormwater Report. 1 The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included in the Stormwater Report, the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the post-construction best management practices. 2 For some complex projects, it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan in the Stormwater Report. In that event, the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. 5.1 225 Whites Path SW Checklist • 04/01/08 Stormwater Report Checklist • Page 2 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report B. Stormwater Checklist and Certification The following checklist is intended to serve as a guide for applicants as to the elements that ordinarily need to be addressed in a complete Stormwater Report. The checklist is also intended to provide conservation commissions and other reviewing authorities with a summary of the components necessary for a comprehensive Stormwater Report that addresses the ten Stormwater Standards. Note: Because stormwater requirements vary from project to project, it is possible that a complete Stormwater Report may not include information on some of the subjects specified in the Checklist. If it is determined that a specific item does not apply to the project under review,please note that the item is not applicable (N.A.) and provide the reasons for that determination. A complete checklist must include the Certification set forth below signed by the Registered Professional Engineer who prepared the Stormwater Report. Registered Professional Engineer’s Certification I have reviewed the Stormwater Report, including the soil evaluation, computations, Long-term Pollution Prevention Plan, the Construction Period Erosion and Sedimentation Control Plan (if included), the Long- term Post-Construction Operation and Maintenance Plan, the Illicit Discharge Compliance Statement (if included) and the plans showing the stormwater management system, and have determined that they have been prepared in accordance with the requirements of the Stormwater Management Standards as further elaborated by the Massachusetts Stormwater Handbook. I have also determined that the information presented in the Stormwater Checklist is accurate and that the information presented in the Stormwater Report accurately reflects conditions at the site as of the date of this permit application. Registered Professional Engineer Block and Signature Kelly Killeen, P.E. CHA Consulting, Inc. 141 Longwater Drive, Suite 104 Norwell, MA 02061 (781) 982-5400 Signature and Date Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment? New development Redevelopment Mix of New Development and Redevelopment 5.1 225 Whites Path SW Checklist • 04/01/08 Stormwater Report Checklist • Page 3 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) LID Measures:Stormwater Standards require LID measures to be considered. Document what environmentally sensitive design and LID Techniques were considered during the planning and design of the project: No disturbance to any Wetland Resource Areas Site Design Practices (e.g. clustered development, reduced frontage setbacks) Reduced Impervious Area (Redevelopment Only) Minimizing disturbance to existing trees and shrubs LID Site Design Credit Requested: Credit 1 Credit 2 Credit 3 Use of “country drainage” versus curb and gutter conveyance and pipe Bioretention Cells (includes Rain Gardens) Constructed Stormwater Wetlands (includes Gravel Wetlands designs) Treebox Filter Water Quality Swale Grass Channel Green Roof Other (describe): Standard 1: No New Untreated Discharges No new untreated discharges Outlets have been designed so there is no erosion or scour to wetlands and waters of the Commonwealth Supporting calculations specified in Volume 3 of the Massachusetts Stormwater Handbook included. 5.1 225 Whites Path SW Checklist • 04/01/08 Stormwater Report Checklist • Page 4 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 2: Peak Rate Attenuation Standard 2 waiver requested because the project is located in land subject to coastal storm flowage and stormwater discharge is to a wetland subject to coastal flooding. Evaluation provided to determine whether off-site flooding increases during the 100-year 24-hour storm. Calculations provided to show that post-development peak discharge rates do not exceed pre- development rates for the 2-year and 10-year 24-hour storms. If evaluation shows that off-site flooding increases during the 100-year 24-hour storm, calculations are also provided to show that post-development peak discharge rates do not exceed pre-development rates for the 100-year 24- hour storm. Standard 3: Recharge Soil Analysis provided. Required Recharge Volume calculation provided. Required Recharge volume reduced through use of the LID site Design Credits. Sizing the infiltration, BMPs is based on the following method: Check the method used. Static Simple Dynamic Dynamic Field1 Runoff from all impervious areas at the site discharging to the infiltration BMP. Runoff from all impervious areas at the site is not discharging to the infiltration BMP and calculations are provided showing that the drainage area contributing runoff to the infiltration BMPs is sufficient to generate the required recharge volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume only to the maximum extent practicable for the following reason: Site is comprised solely of C and D soils and/or bedrock at the land surface M.G.L. c. 21E sites pursuant to 310 CMR 40.0000 Solid Waste Landfill pursuant to 310 CMR 19.000 Project is otherwise subject to Stormwater Management Standards only to the maximum extent practicable. Calculations showing that the infiltration BMPs will drain in 72 hours are provided. Property includes a M.G.L. c. 21E site or a solid waste landfill and a mounding analysis is included. 1 80% TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used. 5.1 225 Whites Path SW Checklist • 04/01/08 Stormwater Report Checklist • Page 5 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 3: Recharge (continued) The infiltration BMP is used to attenuate peak flows during storms greater than or equal to the 10- year 24-hour storm and separation to seasonal high groundwater is less than 4 feet and a mounding analysis is provided. Documentation is provided showing that infiltration BMPs do not adversely impact nearby wetland resource areas. Standard 4: Water Quality The Long-Term Pollution Prevention Plan typically includes the following:  Good housekeeping practices;  Provisions for storing materials and waste products inside or under cover;  Vehicle washing controls;  Requirements for routine inspections and maintenance of stormwater BMPs;  Spill prevention and response plans;  Provisions for maintenance of lawns, gardens, and other landscaped areas;  Requirements for storage and use of fertilizers, herbicides, and pesticides;  Pet waste management provisions;  Provisions for operation and management of septic systems;  Provisions for solid waste management;  Snow disposal and plowing plans relative to Wetland Resource Areas;  Winter Road Salt and/or Sand Use and Storage restrictions;  Street sweeping schedules;  Provisions for prevention of illicit discharges to the stormwater management system;  Documentation that Stormwater BMPs are designed to provide for shutdown and containment in the event of a spill or discharges to or near critical areas or from LUHPPL;  Training for staff or personnel involved with implementing Long-Term Pollution Prevention Plan;  List of Emergency contacts for implementing Long-Term Pollution Prevention Plan. A Long-Term Pollution Prevention Plan is attached to Stormwater Report and is included as an attachment to the Wetlands Notice of Intent. Treatment BMPs subject to the 44% TSS removal pretreatment requirement and the one inch rule for calculating the water quality volume are included, and discharge: is within the Zone II or Interim Wellhead Protection Area is near or to other critical areas is within soils with a rapid infiltration rate (greater than 2.4 inches per hour) involves runoff from land uses with higher potential pollutant loads. The Required Water Quality Volume is reduced through use of the LID site Design Credits. Calculations documenting that the treatment train meets the 80% TSS removal requirement and, if applicable, the 44% TSS removal pretreatment requirement, are provided. 5.1 225 Whites Path SW Checklist • 04/01/08 Stormwater Report Checklist • Page 6 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 4: Water Quality (continued) The BMP is sized (and calculations provided) based on: The ½” or 1” Water Quality Volume or The equivalent flow rate associated with the Water Quality Volume and documentation is provided showing that the BMP treats the required water quality volume. The applicant proposes to use proprietary BMPs, and documentation supporting use of proprietary BMP and proposed TSS removal rate is provided. This documentation may be in the form of the propriety BMP checklist found in Volume 2, Chapter 4 of the Massachusetts Stormwater Handbook and submitting copies of the TARP Report, STEP Report, and/or other third party studies verifying performance of the proprietary BMPs. A TMDL exists that indicates a need to reduce pollutants other than TSS and documentation showing that the BMPs selected are consistent with the TMDL is provided. Standard 5: Land Uses With Higher Potential Pollutant Loads (LUHPPLs) The NPDES Multi-Sector General Permit covers the land use and the Stormwater Pollution Prevention Plan (SWPPP) has been included with the Stormwater Report. The NPDES Multi-Sector General Permit covers the land use and the SWPPP will be submitted prior to the discharge of stormwater to the post-construction stormwater BMPs. The NPDES Multi-Sector General Permit does not cover the land use. LUHPPLs are located at the site and industry specific source control and pollution prevention measures have been proposed to reduce or eliminate the exposure of LUHPPLs to rain, snow, snow melt and runoff, and been included in the long term Pollution Prevention Plan. All exposure has been eliminated. All exposure has not been eliminated and all BMPs selected are on MassDEP LUHPPL list. The LUHPPL has the potential to generate runoff with moderate to higher concentrations of oil and grease (e.g. all parking lots with >1000 vehicle trips per day) and the treatment train includes an oil grit separator, a filtering bioretention area, a sand filter or equivalent. Standard 6: Critical Areas The discharge is near or to a critical area and the treatment train includes only BMPs that MassDEP has approved for stormwater discharges to or near that particular class of critical area. Critical areas and BMPs are identified in the Stormwater Report. 5.1 225 Whites Path SW Checklist • 04/01/08 Stormwater Report Checklist • Page 7 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 7: Redevelopments and Other Projects Subject to the Standards only to the maximum extent practicable The project is subject to the Stormwater Management Standards only to the maximum Extent Practicable as a: Limited Project Small Residential Projects: 5-9 single family houses or 5-9 units in a multi-family development provided there is no discharge that may potentially affect a critical area. Small Residential Projects: 2-4 single family houses or 2-4 units in a multi-family development with a discharge to a critical area Marina and/or boatyard provided the hull painting, service and maintenance areas are protected from exposure to rain, snow, snow melt and runoff Bike Path and/or Foot Path Redevelopment Project Redevelopment portion of mix of new and redevelopment. Certain standards are not fully met (Standard No. 1, 8, 9, and 10 must always be fully met) and an explanation of why these standards are not met is contained in the Stormwater Report. The project involves redevelopment and a description of all measures that have been taken to improve existing conditions is provided in the Stormwater Report. The redevelopment checklist found in Volume 2 Chapter 3 of the Massachusetts Stormwater Handbook may be used to document that the proposed stormwater management system (a) complies with Standards 2, 3 and the pretreatment and structural BMP requirements of Standards 4-6 to the maximum extent practicable and (b) improves existing conditions. Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan must include the following information:  Narrative;  Construction Period Operation and Maintenance Plan;  Names of Persons or Entity Responsible for Plan Compliance;  Construction Period Pollution Prevention Measures;  Erosion and Sedimentation Control Plan Drawings;  Detail drawings and specifications for erosion control BMPs, including sizing calculations;  Vegetation Planning;  Site Development Plan;  Construction Sequencing Plan;  Sequencing of Erosion and Sedimentation Controls;  Operation and Maintenance of Erosion and Sedimentation Controls;  Inspection Schedule;  Maintenance Schedule;  Inspection and Maintenance Log Form. A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan containing the information set forth above has been included in the Stormwater Report. 5.1 225 Whites Path SW Checklist • 04/01/08 Stormwater Report Checklist • Page 8 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control (continued) The project is highly complex and information is included in the Stormwater Report that explains why it is not possible to submit the Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan with the application. A Construction Period Pollution Prevention and Erosion and Sedimentation Control has not been included in the Stormwater Report but will be submitted before land disturbance begins. The project is not covered by a NPDES Construction General Permit. The project is covered by a NPDES Construction General Permit and a copy of the SWPPP is in the Stormwater Report. The project is covered by a NPDES Construction General Permit but no SWPPP been submitted. The SWPPP will be submitted BEFORE land disturbance begins. Standard 9: Operation and Maintenance Plan The Post Construction Operation and Maintenance Plan is included in the Stormwater Report and includes the following information: Name of the stormwater management system owners; Party responsible for operation and maintenance; Schedule for implementation of routine and non-routine maintenance tasks; Plan showing the location of all stormwater BMPs maintenance access areas; Description and delineation of public safety features; Estimated operation and maintenance budget; and Operation and Maintenance Log Form. The responsible party is not the owner of the parcel where the BMP is located and the Stormwater Report includes the following submissions: A copy of the legal instrument (deed, homeowner’s association, utility trust or other legal entity) that establishes the terms of and legal responsibility for the operation and maintenance of the project site stormwater BMPs; A plan and easement deed that allows site access for the legal entity to operate and maintain BMP functions. Standard 10: Prohibition of Illicit Discharges The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges; An Illicit Discharge Compliance Statement is attached; NO Illicit Discharge Compliance Statement is attached but will be submitted prior to the discharge of any stormwater to post-construction BMPs. Appendix A Soils United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Barnstable County, MassachusettsNatural Resources Conservation Service September 28, 2021 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................11 Map Unit Descriptions.........................................................................................11 Barnstable County, Massachusetts.................................................................13 252A—Carver coarse sand, 0 to 3 percent slopes......................................13 252B—Carver coarse sand, 3 to 8 percent slopes......................................14 252C—Carver coarse sand, 8 to 15 percent slopes...................................16 602—Urban land.........................................................................................18 References............................................................................................................19 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 46157704615840461591046159804616050461612046161904615770461584046159104615980461605046161204616190400100 400170 400240 400310 400380 400450 400520 400590 400660 400730 400800 400100 400170 400240 400310 400380 400450 400520 400590 400660 400730 400800 41° 41' 29'' N 70° 12' 2'' W41° 41' 29'' N70° 11' 30'' W41° 41' 14'' N 70° 12' 2'' W41° 41' 14'' N 70° 11' 30'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 19N WGS84 0 150 300 600 900 Feet 0 45 90 180 270 Meters Map Scale: 1:3,340 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 Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features 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 1:25,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Barnstable County, Massachusetts Survey Area Data: Version 17, Jun 9, 2020 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 10, 2018—Nov 17, 2018 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. Custom Soil Resource Report 10 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 252A Carver coarse sand, 0 to 3 percent slopes 20.0 47.1% 252B Carver coarse sand, 3 to 8 percent slopes 0.9 2.2% 252C Carver coarse sand, 8 to 15 percent slopes 4.1 9.6% 602 Urban land 17.4 41.0% Totals for Area of Interest 42.5 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate Custom Soil Resource Report 11 pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Barnstable County, Massachusetts 252A—Carver coarse sand, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2y07w Elevation: 0 to 990 feet Mean annual precipitation: 36 to 71 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 240 days Farmland classification: Not prime farmland Map Unit Composition Carver, coarse sand, and similar soils:80 percent Minor components:20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Carver, Coarse Sand Setting Landform:Moraines, outwash plains Landform position (two-dimensional):Summit, shoulder Landform position (three-dimensional):Side slope, crest, tread Down-slope shape:Convex, linear Across-slope shape:Linear Parent material:Sandy glaciofluvial deposits Typical profile Oi - 0 to 2 inches: slightly decomposed plant material Oe - 2 to 3 inches: moderately decomposed plant material A - 3 to 7 inches: coarse sand E - 7 to 10 inches: coarse sand Bw1 - 10 to 15 inches: coarse sand Bw2 - 15 to 28 inches: coarse sand BC - 28 to 32 inches: coarse sand C - 32 to 67 inches: coarse sand Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Excessively drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat):Moderately high to very high (1.42 to 14.17 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 4.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3s Hydrologic Soil Group: A Ecological site: F149BY005MA - Dry Outwash Custom Soil Resource Report 13 Hydric soil rating: No Minor Components Deerfield Percent of map unit:10 percent Landform:Outwash deltas, kame terraces, outwash terraces, outwash plains Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Concave Hydric soil rating: No Hinckley Percent of map unit:5 percent Landform:Kame terraces, outwash terraces, eskers, moraines, outwash plains, kames, outwash deltas Landform position (two-dimensional):Footslope, shoulder, backslope, summit, toeslope Landform position (three-dimensional):Nose slope, side slope, crest, head slope, riser, tread Down-slope shape:Convex Across-slope shape:Convex Hydric soil rating: No Merrimac Percent of map unit:3 percent Landform:Kame terraces, outwash terraces, outwash deltas Landform position (three-dimensional):Riser, tread Down-slope shape:Linear Across-slope shape:Linear Hydric soil rating: No Mashpee Percent of map unit:2 percent Landform:Terraces, depressions, drainageways Landform position (three-dimensional):Tread Down-slope shape:Concave Across-slope shape:Concave Hydric soil rating: Yes 252B—Carver coarse sand, 3 to 8 percent slopes Map Unit Setting National map unit symbol: 2y07x Elevation: 0 to 240 feet Mean annual precipitation: 36 to 71 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 240 days Farmland classification: Not prime farmland Custom Soil Resource Report 14 Map Unit Composition Carver, coarse sand, and similar soils:80 percent Minor components:20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Carver, Coarse Sand Setting Landform:Moraines, outwash plains Landform position (two-dimensional):Summit, shoulder, backslope, footslope, toeslope Landform position (three-dimensional):Crest, head slope, nose slope, side slope, tread Down-slope shape:Convex, linear Across-slope shape:Linear Parent material:Sandy glaciofluvial deposits Typical profile Oi - 0 to 2 inches: slightly decomposed plant material Oe - 2 to 3 inches: moderately decomposed plant material A - 3 to 7 inches: coarse sand E - 7 to 10 inches: coarse sand Bw1 - 10 to 15 inches: coarse sand Bw2 - 15 to 28 inches: coarse sand BC - 28 to 32 inches: coarse sand C - 32 to 67 inches: coarse sand Properties and qualities Slope:3 to 8 percent Depth to restrictive feature:More than 80 inches Drainage class:Excessively drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately high to very high (1.42 to 14.17 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 4.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3s Hydrologic Soil Group: A Ecological site: F149BY005MA - Dry Outwash Hydric soil rating: No Minor Components Deerfield Percent of map unit:10 percent Landform:Outwash deltas, kame terraces, outwash terraces, outwash plains Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Concave Hydric soil rating: No Custom Soil Resource Report 15 Hinckley Percent of map unit:5 percent Landform:Eskers, moraines, outwash plains, kames, outwash deltas, kame terraces, outwash terraces Landform position (two-dimensional):Footslope, shoulder, backslope, summit, toeslope Landform position (three-dimensional):Nose slope, side slope, crest, head slope, riser, tread Down-slope shape:Convex Across-slope shape:Convex Hydric soil rating: No Merrimac Percent of map unit:3 percent Landform:Outwash terraces, outwash deltas, kame terraces Landform position (three-dimensional):Tread, riser Down-slope shape:Linear Across-slope shape:Linear Hydric soil rating: No Mashpee Percent of map unit:2 percent Landform:Drainageways, terraces, depressions Landform position (three-dimensional):Tread Down-slope shape:Concave Across-slope shape:Concave Hydric soil rating: Yes 252C—Carver coarse sand, 8 to 15 percent slopes Map Unit Setting National map unit symbol: 2y07z Elevation: 0 to 250 feet Mean annual precipitation: 36 to 71 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 240 days Farmland classification: Not prime farmland Map Unit Composition Carver, coarse sand, and similar soils:80 percent Minor components:20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Carver, Coarse Sand Setting Landform:Moraines, outwash plains Landform position (two-dimensional):Shoulder, footslope, backslope Landform position (three-dimensional):Crest, head slope, nose slope, side slope, riser Custom Soil Resource Report 16 Down-slope shape:Convex, linear Across-slope shape:Linear Parent material:Sandy glaciofluvial deposits Typical profile Oi - 0 to 2 inches: slightly decomposed plant material Oe - 2 to 3 inches: moderately decomposed plant material A - 3 to 7 inches: coarse sand E - 7 to 10 inches: coarse sand Bw1 - 10 to 15 inches: coarse sand Bw2 - 15 to 28 inches: coarse sand BC - 28 to 32 inches: coarse sand C - 32 to 67 inches: coarse sand Properties and qualities Slope:8 to 15 percent Depth to restrictive feature:More than 80 inches Drainage class:Excessively drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately high to very high (1.42 to 14.17 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 4.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: A Ecological site: F149BY005MA - Dry Outwash Hydric soil rating: No Minor Components Deerfield Percent of map unit:10 percent Landform:Outwash deltas, kame terraces, outwash terraces, outwash plains Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Concave Hydric soil rating: No Merrimac Percent of map unit:5 percent Landform:Outwash deltas, kame terraces, outwash terraces Landform position (three-dimensional):Tread, riser Down-slope shape:Linear Across-slope shape:Linear Hydric soil rating: No Hinckley Percent of map unit:5 percent Landform:Kames, outwash deltas, kame terraces, outwash terraces, eskers, moraines, outwash plains Custom Soil Resource Report 17 Landform position (two-dimensional):Shoulder, backslope, footslope, summit, toeslope Landform position (three-dimensional):Nose slope, side slope, crest, head slope, riser, tread Down-slope shape:Convex Across-slope shape:Convex Hydric soil rating: No 602—Urban land Map Unit Setting National map unit symbol: 98s7 Frost-free period: 120 to 220 days Farmland classification: Not prime farmland Map Unit Composition Urban land:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Urban Land Setting Parent material:Excavated and filled land Minor Components Udipsamments Percent of map unit:15 percent Hydric soil rating: Unranked Custom Soil Resource Report 18 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 19 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 20 t5form11 (1)Form 11 – Soil Suitability Assessment for On-Site Sewage Disposal • Page 1 of 5 Commonwealth of Massachusetts City/Town of Yarmouth Form 11 - Soil Suitability Assessment for On-Site Sewage Disposal A. Facility Information Two Twenty Five White's Path Units Two and Three, LLC Owner Name 225 White's Path Street Address Maps 98 & 99 Lot 33C Map/Lot # Yarmouth City MA State 02664 Zip Code B. Site Information 1. (Check one) New Construction Upgrade 2. Soil Survey USDA/NRCS Web Source Carver coarse sand Soil Map Unit Carver Soil Series Outwash Plain Landform Droughty Soil Limitations Glacial Outwash Soil Parent material 3.Surficial Geological Report Year Published/Source Map Unit Description of Geologic Map Unit: 4. Flood Rate Insurance Map Within a regulatory floodway? Yes No 5.Within a velocity zone? Yes No 6. Within a Mapped Wetland Area? Yes No If yes, MassGIS Wetland Data Layer: Wetland Type 7. Current Water Resource Conditions (USGS): 4/2022 Month/Day/ Year Range: Above Normal Normal Below Normal 8. Other references reviewed: (Zone II, IWPA, Zone A, EEA Data Portal, etc.) t5form11 (1)Form 11 – Soil Suitability Assessment for On-Site Sewage Disposal • Page 2 of 5 Commonwealth of Massachusetts City/Town of Yarmouth Form 11 - Soil Suitability Assessment for On-Site Sewage Disposal C. On-Site Review (minimum of two holes required at every proposed primary and reserve disposal area) Deep Observation Hole Number:TP-1 Hole # 5/13/22 Date 10:30 AM Time 60F Overcast Weather Latitude Longitude 1. Land Use Warehouse/Distribution (e.g., woodland, agricultural field, vacant lot, etc.) Woods Vegetation None Surface Stones (e.g., cobbles, stones, boulders, etc.) 2% Slope (%) Description of Location: 2. Soil Parent Material:Glacial Outwash Outwash Plain Landform Plain Position on Landscape (SU, SH, BS, FS, TS, Plain) 3. Distances from:Open Water Body >100 feet Drainage Way >30 feet Wetlands >100 feet Property Line >50 feet Drinking Water Well feet Other feet 4. Unsuitable Materials Present: Yes No If Yes: Disturbed Soil/Fill Material Weathered/Fractured Rock Bedrock 5. Groundwater Observed: Yes No If yes:Depth to Weeping in Hole Depth to Standing Water in Hole Soil Log Depth (in)Soil Horizon /Layer Soil Texture (USDA Soil Matrix: Color- Moist (Munsell) Redoximorphic Features Coarse Fragments % by Volume Soil Structure Soil Consistence (Moist) Other Depth Color Percent Gravel Cobbles & Stones 0-9 A Sandy Loam 10Y/R 3/2 Cnc : Massive FriableDpl: 9-13 E Loamy Sand 10Y/R 5/1 Cnc : Massive FriableDpl: 13-27 B Loamy Sand 10YR 6/8 Cnc :Single Grain LooseDpl: 27-48 C1 Medium Sand 2.5Y 7/6 Cnc :Single Grain LooseDpl: 48-180 C2 Medium Sand 2.5Y 7/2 Cnc :Single Grain LooseDpl: Cnc : Dpl: Additional Notes: t5form11 (1)Form 11 – Soil Suitability Assessment for On-Site Sewage Disposal • Page 3 of 5 Commonwealth of Massachusetts City/Town of Yarmouth Form 11 - Soil Suitability Assessment for On-Site Sewage Disposal C. On-Site Review (minimum of two holes required at every proposed primary and reserve disposal area) Deep Observation Hole Number:TP-2 Hole # 05/13/2022 Date 11:30 am Time 60 Overcast Weather Latitude Longitude 1. Land Use:Warehouse/Distribution (e.g., woodland, agricultural field, vacant lot, etc.) Woods Vegetation None Surface Stones (e.g., cobbles, stones, boulders, etc.) 1% Slope (%) Description of Location: 2. Soil Parent Material: Glacial Outwash Outwash Plain Landform Plain Position on Landscape (SU, SH, BS, FS, TS, Plain) 3. Distances from:Open Water Body >100 feet Drainage Way >60 feet Wetlands >100 feet Property Line >50 feet Drinking Water Well N/A feet Other feet 4. Unsuitable Materials Present: Yes No If Yes: Disturbed Soil/Fill Material Weathered/Fractured Rock Bedrock 5. Groundwater Observed: Yes No If yes:Depth to Weeping in Hole Depth Standing Water in Hole Soil Log Depth (in)Soil Horizon /Layer Soil Texture (USDA) Soil Matrix: Color- Moist (Munsell) Redoximorphic Features Coarse Fragments % by Volume Soil Structure Soil Consistence (Moist) Other Depth Color Percent Gravel Cobbles & Stones 0-10 A Sandy Loam 10 YR 3/2 Cnc : Massive FriableDpl: 10-13 E Loamy Sand 10YR 5/1 Cnc : Massive FriableDpl: 13-28 B Loamy Sand 10 YR 6/8 Cnc :Single Grain LooseDpl: 28-39 C1 Medium Sand 2.5Y 7/6 Cnc :Single Grain LooseDpl: 39-192 C2 Medium Sand 2.5Y 7/2 Cnc :Single Grain LooseDpl: Cnc : Dpl: Additional Notes: t5form11 (2)Form 11 – Soil Suitability Assessment for On-Site Sewage Disposal • Page 2 of 5 Commonwealth of Massachusetts City/Town of Yarmouth Form 11 - Soil Suitability Assessment for On-Site Sewage Disposal C. On-Site Review (minimum of two holes required at every proposed primary and reserve disposal area) Deep Observation Hole Number:TP-3 Hole # 5/13/22 Date 12:30 PM Time 60F Overcast Weather Latitude Longitude 1. Land Use Warehouse/Distribution (e.g., woodland, agricultural field, vacant lot, etc.) Woods Vegetation None Surface Stones (e.g., cobbles, stones, boulders, etc.) 2% Slope (%) Description of Location: 2. Soil Parent Material:Glacial Outwash Outwash Plain Landform Plain Position on Landscape (SU, SH, BS, FS, TS, Plain) 3. Distances from:Open Water Body >100 feet Drainage Way >30 feet Wetlands >100 feet Property Line >40 feet Drinking Water Well feet Other feet 4. Unsuitable Materials Present: Yes No If Yes: Disturbed Soil/Fill Material Weathered/Fractured Rock Bedrock 5. Groundwater Observed: Yes No If yes:Depth to Weeping in Hole Depth to Standing Water in Hole Soil Log Depth (in)Soil Horizon /Layer Soil Texture (USDA Soil Matrix: Color- Moist (Munsell) Redoximorphic Features Coarse Fragments % by Volume Soil Structure Soil Consistence (Moist) Other Depth Color Percent Gravel Cobbles & Stones 0-9 A Sandy Loam 10Y/R 3/2 Cnc : Massive FriableDpl: 9-12 E Loamy Sand 10Y/R 5/1 Cnc : Massive FriableDpl: 12-22 B Loamy Sand 10YR 6/8 Cnc :Single Grain LooseDpl: 22-36 C1 Medium Sand 2.5Y 7/6 Cnc :Single Grain LooseDpl: 36-198 C2 Medium Sand 2.5Y 7/2 Cnc :Single Grain LooseDpl: Cnc : Dpl: Additional Notes: t5form11 (2)Form 11 – Soil Suitability Assessment for On-Site Sewage Disposal • Page 3 of 5 Commonwealth of Massachusetts City/Town of Yarmouth Form 11 - Soil Suitability Assessment for On-Site Sewage Disposal C. On-Site Review (minimum of two holes required at every proposed primary and reserve disposal area) Deep Observation Hole Number:TP-4 Hole # 05/13/2022 Date 9:00 am Time 60 Overcast Weather Latitude Longitude 1. Land Use:Warehouse/Distribution (e.g., woodland, agricultural field, vacant lot, etc.) Woods Vegetation None Surface Stones (e.g., cobbles, stones, boulders, etc.) 1% Slope (%) Description of Location: 2. Soil Parent Material: Glacial Outwash Outwash Plain Landform Plain Position on Landscape (SU, SH, BS, FS, TS, Plain) 3. Distances from:Open Water Body >100 feet Drainage Way >50 feet Wetlands >100 feet Property Line >100 feet Drinking Water Well N/A feet Other feet 4. Unsuitable Materials Present: Yes No If Yes: Disturbed Soil/Fill Material Weathered/Fractured Rock Bedrock 5. Groundwater Observed: Yes No If yes:Depth to Weeping in Hole Depth Standing Water in Hole Soil Log Depth (in)Soil Horizon /Layer Soil Texture (USDA) Soil Matrix: Color- Moist (Munsell) Redoximorphic Features Coarse Fragments % by Volume Soil Structure Soil Consistence (Moist) Other Depth Color Percent Gravel Cobbles & Stones 0-10 A Sandy Loam 10 YR 3/2 Cnc : Massive FriableDpl: 10-13 E Loamy Sand 10YR 5/1 Cnc : Massive FriableDpl: 13-28 B Loamy Sand 10 YR 6/8 Cnc :Single Grain LooseDpl: 28-42 C1 Medium Sand 2.5Y 7/6 Cnc :Single Grain LooseDpl: 42-180 C2 Fine Sand 2.5Y 7/2 Cnc :Single Grain LooseDpl: Cnc : Dpl: Additional Notes: HIGH GROUND-WATER LEVEL COMPUTATION Date: Site Location:Permit: Owner:Phone: Contractor:Phone: Notes: STEP 1 Date:0 mm/dd/yy feet below ls STEP 2 A) Appropriate index well B) Water-level range zone STEP 3 mm/yy STEP 4 0 STEP 5 0 NOTE*Tables 1-9 "Potential Water-Level Rise" are attached as worksheets to this file. Using Table of Potential Water Level Rise for index well (STEP 2A), current depth to water level for index well (STEP 3), and water-level zone (STEP 2B) determine water-level adjustment. Estimate depth to high water by subtracting the water-level adjustment (STEP 4) from measured depth to water level at site (STEP 1). Using monthly "Current Water Resources Conditions" determine current depth to water level for index well. Measure depth to water table to nearest 1/10 ft. (depth is in feet below land surface) Using Water-Level Range Zone and Index Well Map locate site and determine: monthly index well data: www.capecodcommission.org/wells.html