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05.06.2021_64Pleasant_Drainage Report_Stamped
DRAINAGE REPORT For BERKELEY INVESTMENTS PROPOSED "Lab Redevelopment" 64 Pleasant Street Watertown, Massachusetts Middlesex County Prepared by: BOHLER 45 Franklin Street, 5th Floor Boston, MA 02110 (617) 849-8040 TEL. H OF dfq'4 T 6 �i7'i_ rn A.R I �STE Zachary L. Richards Massachusetts P.E. Lic. #51848 BOHLE May 06, 2021 #M201051 BOHLER TABLE OF CONTENTS I. EXECUTIVE SUMMARY...................................................................................................... 4 II. EXISTING SITE CONDITIONS ............................................................................................ 5 ExistingSite Description............................................................................................................. 5 On-Site Soil Information............................................................................................................. 5 Existing Collection and Conveyance........................................................................................... 5 Existing Watersheds and Design Point Information.................................................................... 6 III. PROPOSED SITE CONDITIONS .......................................................................................... 8 Proposed Development Description............................................................................................ 8 Proposed Development Collection and Conveyance................................................................... 8 Proposed Watersheds and Design Point Information.................................................................. 8 IV. METHODOLOGY................................................................................................................. 10 PeakFlow Calculations............................................................................................................. 10 V. STORMWATER MANAGEMENT STANDARDS............................................................. 11 Standard#1: No New Untreated Discharges............................................................................. 11 Standard#2: Peak Rate Attenuation.......................................................................................... 11 Standard#3: Recharge............................................................................................................... 11 Standard#4: Water Quality....................................................................................................... 11 Standard#5: Land Use with Higher Potential Pollutant Loads................................................. 12 Standard#6: Critical Areas........................................................................................................ 12 Standard#7: Redevelopment..................................................................................................... 12 Standard#8: Construction Period Pollution Prevention and Erosion and Sedimentation Control ................................................................................................................................................... 12 Standard#9: Operation and Maintenance Plan (O&M Plan).................................................... 13 Standard#10: Prohibition of Illicit Discharges......................................................................... 13 VI. SUMMARY........................................................................................................................... 14 -1- BOHLER LIST OF TABLES Table 1.1: Design Point Peak Runoff Rate Summary..................................................................... 4 Table 4.1: Watertown Stormwater Mangement Regulations Rainfall Intensities ........................ 10 Table 5.1: Design Point Peak Runoff Rate Summary................................................................... 14 -2- BOHLER APPENDICES APPENDIX A: MASSACHUSETTS STORMWATER MANAGEMENT CHECKLIST APPENDIX B: PROJECT LOCATION MAPS ➢ USGS MAP ➢ FEMA FIRMETTE APPENDIX C: SOIL AND WETLAND INFORMATION ➢ NCRS CUSTOM SOIL RESOURCE REPORT ➢ REPORT OF GEOTECHNICAL INVESTIGATION APPENDIX D: EXISTING CONDITIONS HYDROLOGIC ANALYSIS ➢ EXISTING CONDITIONS DRAINAGE MAP ➢ EXISTING CONDITIONS HYDROCAD COMPUTATIONS APPENDIX E: PROPOSED CONDITIONS HYDROLOGIC ANALYSIS ➢ PROPOSED CONDITIONS DRAINAGE MAP ➢ PROPOSED CONDITIONS HYDROCAD CALCULATIONS APPENDIX F: STORMWATER CALCULATIONS ➢ MA STANDARD#3 -RECHARGE AND DRAWDOWN TIME ➢ MA STANDARD#4-WATER QUALITY AND TSS REMOVAL ➢ CDS WATER QUALITY STRUCTURE SIZING ➢ MOUNDING ANALYSIS AND NARRATIVE ➢ PHOSPHORUS REMOVAL ANALYSIS ➢ WATERTOWN RAINFALL DATA APPENDIX G: OPERATION AND MAINTENANCE ➢ STORMWATER OPERATION AND MAINTENANCE PLAN ➢ INSPECTION REPORT ➢ INSPECTION AND MAINTENANCE LOG FORM ➢ LONG-TERM POLLUTION PREVENTION PLAN ➢ SPILL PREVENTION ➢ MANUFACTURER'S INSPECTION AND MAINTENANCE MANUALS ➢ BMP MAINTENANCE ACCESS AREAS -3- BOHLER I. EXECUTIVE SUMMARY This report examines the changes in drainage that can be expected as the result of the proposed redevelopment of the site area and parking lots located at 64 Pleasant Street in Watertown, MA. The overall property consists of approximately 2.53 acres of land and contains an existing office building,parking areas, and landscape amenities. The existing footprint of the building is proposed to remain unchanged while the associated parking and landscaped areas of the site are proposed to be redeveloped. The analysis area is comprised of the redesigned parking and landscape areas on the property and excludes the existing building areas which are to remain unchanged. The analysis area herein is referred to as the "Site". The proposed project includes the redevelopment of the existing parking areas and landscaping in order to provide a more efficient parking layout, enhanced landscaping, stormwater management components, and associated utilities. This report addresses a comparative analysis of the pre- and post-development site runoff conditions. Additionally, this report provides calculations documenting the design and compliance of the proposed stormwater conveyance/management system as illustrated within the accompanying Site Development Plans prepared by Bohler. The project will also provide erosion and sedimentation controls during the demolition and construction periods, as well as long term stabilization of the site. For the purposes of this analysis the pre- and post-development drainage conditions were analyzed at one (1) "design point" where stormwater runoff currently drains to under existing conditions. These design points are described in further detail in Section II below. A summary of the existing and proposed conditions peak runoff rates for the 2-, 10-, 25-, and 100-year storms can be found in Table 1.1 below. In addition, the project has been designed to meet or exceed the Stormwater Management Standards as detailed herein. Table 1.1: Desi2n Point Peak Runoff Rate Summary F oint of 2-Year Storm 10-Year Storm 25-Year Storm 100-Year Storm nalysis Pre Post 4 Pre Post A Pre Post 4 Pre Post 4 DP1 6.34 6.30 -0.04 1 10.17 10.16 -0.01 13.07 13.05 -0.02 I 18.89 18.28 I -0.61 *Flows are represented in cubic feet per second(cfs) -4- BOHLER II. EXISTING SITE CONDITIONS Existing Site Description The Site consists of approximately 1.45 acres of land located along the southern side of Pleasant Street in the Town of Watertown, Massachusetts. The northern portion of the site contains an existing parking lot to be redeveloped. The southern and middle portions of the site contain the existing office building to remain and associated parking to be redeveloped. The Charles River is located south of the site. Commercial office buildings abut the property to the east, and the Charles River Greenway abuts the property to the west. On-Site Soil Information The majority of the soils at the site are mapped as Urban Land,which does not have a classification by the Natural Resource Conservation Service. Soil borings have been performed by Sanborn Head and show that the soil consists of fill over a natural sand and gravel deposit. The boring logs are included in Appendix C. For the purposes of this report and analysis, the natural sand and gravel deposit categorized as Sandy Loam, Hydrologic Soil Group (HSG) B. As such, a Rawl's Rate for infiltration of 1.02 inches per hour has been utilized for stormwater calculations. Refer to Appendix C for additional information. Stabilized groundwater measurements were collected by Sanborn Head from on-site groundwater monitoring wells on January 19,2021. Based on the measurements,groundwater was encountered between approximately 5.5 and 5.9 feet below ground surface, which corresponds to approximately between EL. 5.6 feet and El.3.1 feet. Based on the stabilized groundwater readings, the groundwater readings, the groundwater flows from north to south towards the Charles River. Groundwater measurements are provided on the logs and stabilized groundwater data are summarized in Appendix C. Existing Collection and Convevance The rear portion the site is relatively flat, while the front parking lot has slopes ranging from 3% to 12%in some areas. Both parking lots drain from west to east via overland flow into catch basins where they eventually discharge into the Charles River via the existing historic drainage channel at the eastern end of the building, abutting 1 Brook Street. A Vortech unit at the northeastern most -5- BOHLERI building point serves the front parking lot as a water quality unit. The existing conditions analysis only models runoff area within the site. Existing Watersheds and Design Point Information The site was subdivided into four (4) separate sub catchments for the existing conditions as described below to analyze existing and proposed flow rates at each design point. The minimum time of concentration for all proposed areas is calculated as 6 minutes (0.1 hr). The pre- and post-development drainage conditions for the site were then analyzed at one (1) "design point"where stormwater runoff currently drains to under existing conditions.Design Point #1 (DP I) is defined as the historic underground drainage channel located at the eastern end of the building abutting 1 Brook Street. Under existing conditions, this design point receives stormwater flows from Subcatchment EX-1, Subcatchment EX-2 and the existing building area (defined as EX-la and EX-2a). Subcatchment EX-1 in total is 0.685 acres consisting of pavement and landscaping.This area flows overland from west to east across the site via overland flow into catch basins where it discharges into a drainage channel at the eastern portion of the site abutting 1 Brook Street. The time of concentration for EX-1 was calculated as 6.0 minutes, as further detailed in the drainage calculations. Subcatchment EX-1 a in total is 0.309 acres of building area and was classified during calculations as "existing building area". This area discharges via roof drains at grade to catch basins in subcatchment EX-1 where it discharges into the drainage channel at the eastern portion of the Site. The time of concentration for EX-la was calculated as 6.0 minutes, as further detailed in the drainage calculations. Subcatchment EX-2 in total is 0.765 acres of pavement and landscaping. This area generally ponds on the surface of the rear parking lot on site during large storm events and then discharges into the drainage channel at the eastern portion of the Site. The time of concentration for EX-2 was calculated as 6.0 minutes, as further detailed in the drainage calculations. -6- BOHLERI Subcatchment EX-2a in total is 0.458 acres of building area and was classified during calculations as "existing building area" similar to EX-la. This area drains into the southern parking lot at the site and then discharges into the drainage channel at the eastern portion of the Site. The time of concentration for EX-2a was calculated as 6.0 minutes, as further detailed in the drainage calculations. Refer to Table 1.1 and 5.1 for the calculated existing conditions peak rates of runoff. For additional hydrologic information, refer to Appendix D and the Drainage Area Maps in the appendices of this report for a graphical representation of the existing drainage areas. -7- BOHLER III. PROPOSED SITE CONDITIONS Proposed Development Description The proposed project consists of the renovation of the existing office building and redevelopment of existing parking areas and landscaped areas. The existing footprint of the building is proposed to remain unchanged while the associated parking, loading, and landscaped areas of the site are proposed to be redeveloped. Additional improvements include a new stormwater management system and the construction of associated building utilities. The majority of the site has been designed to drain to deep-sump, hooded catch basins. The catch basins will capture and convey stormwater runoff,via an underground pipe system,to water quality treatment units,and ultimately to one of two (2)proposed subsurface infiltration basins. Proposed Development Collection and Convevance Deep sump hooded catch basins are proposed to collect and route runoff from the paved parking areas through water quality units for pre-treatment prior to discharge into the stormwater system. The best management practices (BMPs) incorporated into the proposed stormwater management system have been designed to meet the total suspended solid (TSS) removal requirements as set forth in the Massachusetts Department of Environmental Protection Stormwater Handbook standards. Refer to Appendix F for calculations. In addition, a Stormwater Operation and Maintenance(O&M)Plan,attached in Appendix G,has been developed which includes scheduled maintenance and periodic inspections of stormwater management structures [i.e catch basins and infiltration basins]. Proposed Watersheds and Design Point Information The project has been designed to maintain existing drainage watersheds to the greatest extent possible,with the same design points described in Section II above. The site was subdivided into four (4) separate sub catchments for the proposed conditions as described below. The minimum time of concentration for all proposed areas is calculated as 6 minutes (0.1 hr). Project Area 1, PR-1, consists of 0.685 acres of area consisting of pavement and landscaped area. This area drains to proposed catch basins and is routed through a water quality unit for pretreatment -8- BOHLERI prior to discharge into a subsurface infiltration basin. The time of concentration for PR-1 was calculated as the minimum of 6 minutes. PR-la consists of 0.309 acres of building area and was classified during calculations as "existing building area"similar to EX-1 a and EX-2a. This area drains to proposed perimeter roof drains and is routed into a subsurface infiltration basin. The time of concentration for PR-la was calculated as the minimum of 6 minutes. Project Area 2, PR-2, consists of 0.765 acres of area consisting of pavement and landscaped area. This area drains to proposed catch basins and is routed through a water quality unit for pretreatment prior to discharge into a subsurface infiltration basin. The time of concentration for PR-2 was calculated as the minimum of 6 minutes. PR-2a consists of 0.458 acres of building area and was classified during calculations as "existing building area"similar to EX-1 a and EX-2a. This area drains to proposed perimeter roof drains and is routed into a subsurface infiltration basin. The time of concentration for PR-2a was calculated as the minimum of 6 minutes. Refer to Table 1.1 and 5.1 for the calculated proposed conditions peak rates of runoff. For additional hydrologic information, refer to Appendix D and the Drainage Area Maps in the appendices of this report for a graphical representation of the proposed drainage areas. -9- BOHLER IV. METHODOLOGY Peak Flow Calculations Methodology utilized to design the proposed stormwater management system includes compliance with the guidelines set forth in the latest edition of the Massachusetts DEP Stormwater Handbook. The pre- and post-development runoff rates being discharged from the site were computed using the HydroCAD computer program. The drainage area and outlet information were entered into the program, which routes storm flows based on NRCS TR-20 and TR-55 methods. The other components of the model were determined following standard NRCS procedures for Curve Numbers (CNs) and times of concentrations documented in the appendices of this report. The rainfall data utilized and listed below in table 4.1 below for stormwater calculations is based on the webtool "Extreme Precipitation in New York and New England" developed by the Northeast Regional Climate Center at Cornell University and the Natural Resources Conservation Service. Refer to Appendix F for more information. Table 4.1: Cornell Universitv Rainfall Intensities Frequency 2 year 10 year 25 year 100 year Rainfall* (inches) 3.2 4.9 6.2 8.9 *Values derived from Cornell University"Extreme Precipitation in New York and New England The proposed stormwater management as designed will provide a decrease in peak rates of runoff from the proposed facility for the 2-, 10-, 25- and 100-year design storm events. Additionally, the proposed project meets, or exceeds,the MADEP Stormwater Management standards. Compliance with these standards is described further below. -io- BOHLER V. STORMWATER MANAGEMENT STANDARDS Standard#1: No New Untreated Discharges The project has been designed so that proposed impervious areas shall be collected and passed through the proposed drainage system for treatment prior to discharge. Standard#2: Peak Rate Attenuation As outlined in Table 1.1 and Table 5.4, the development of the site and the proposed stormwater management system, have been designed so that post-development peak rates of runoff are below pre-development conditions for the 2-, 10-, 25- and 100-year storm events at all design points. Standard #3: Recharge The stormwater runoff from the project will be collected and diverted to two proposed infiltration basins. The project as proposed will involve the creation of 2,928 square feet of new impervious area and is required to infiltrate 24 cubic feet of stormwater as defined in Stormwater Standard 3. Proposed infiltration basin 1 will provide 1,463 cubic feet of volume below the lowest outlet for groundwater recharge, and proposed infiltration basin 2 will provide 1,465 cubic feet of volume below the lowest outlet for groundwater recharge. Refer to Appendix F of this report for calculations documenting required and provided recharge volumes. The DEP Stormwater Standards require that the infiltration BMP drains completely within 72 hours of the end of the storm event. Calculations showing that the proposed infiltration basin l will drain within 14.8 hours and proposed infiltration basin 2 will drain within 14.8 hours are included in Appendix F of this report. A groundwater mounding analysis has been provided in Appendix F of this report, as there is less than a four (4) foot separation to estimated seasonal high ground water. The analysis shows that the groundwater mound will have no effect on the proposed system. Standard #4: Water Oualitv Water quality treatment is provided via deep sump catch basins, three (3) water quality units, and (2) infiltration basins. TSS removal calculations are included in Appendix F of this report. The proposed infiltration systems will be sized to provide the 0.5 inches of runoff volume for the _11_ BOHLER // impervious paved area of the site (54,438 square feet), and as such will provide a minimum of 2,268 cubic feet of water quality volume as defined in Stormwater Standard 4.Proposed infiltration basin 1 provides 1,463 cubic feet of water quality volume below the lowest outlet for water quality treatment, and proposed infiltration basin 2 provides 1,465 cubic feet of water quality volume below the lowest outlet. Total water quality of 2,6928 cubic feet exceeds the required amount of 2,268 cubic feet. Refer to Appendix F of this report for calculations documenting required and provided water quality volumes. The Town of Watertown requires redevelopment projects to remove 60% of Total Phosphorus (TP) prior to discharge. The proposed project achieves a weighted TP removal rate of 86% by routing impervious area runoff through the two(2)infiltration systems,which provide the required phosphorus removal via infiltration prior to any discharge entering the existing public drainage infrastructure. Supporting sizing and TP removal calculations can be found in Appendix F of this report. Standard#5: Land Use with Higher Potential Pollutant Loads Not Applicable for this project. Standard#6: Critical Areas Not Applicable for this project. Standard#7: Redevelopment Not Applicable for this project. Standard #8: Construction Period Pollution Prevention and Erosion and Sedimentation Control The proposed project will provide construction period erosion and sedimentation controls as indicated within the site plan set provided for this project. This includes a proposed construction exit,protection for stormwater inlets,protection around temporary material stock piles and various other techniques as outlined on the erosion and sediment control sheets. Additionally, the project is required to file a Notice of Intent with the US EPA and implement a Stormwater Pollution Prevention Plan (SWPPP) during the construction period. The SWPPP will be prepared prior to -iz- BOHLERI the start of construction and will be implemented by the site contractor under the guidance and responsibility of the project's proponent. Standard #9: Operation and Maintenance Plan (O&M Plan) An Operation and Maintenance (O&M) Plan for this site has been prepared and is included in Appendix G of this report. The O&M Plan outlines procedures and time tables for the long term operation and maintenance of the proposed site stormwater management system, including initial inspections upon completion of construction, and periodic monitoring of the system components, in accordance with established practices and the manufacturer's recommendations. The O&M Plan includes a list of responsible parties and an estimated budget for inspections and maintenance. Standard#10: Prohibition of Illicit Discharees The proposed stormwater system will only convey allowable non-stormwater discharges (firefighting waters, irrigation, air conditioning condensates, etc.) and will not contain any illicit discharges from prohibited sources. An Illicit Discharge Statement is included in Appendix G of this report. -13- BOHLERI VI. SUMMARY In summary, the proposed stormwater management system illustrated on the drawings prepared by Bohler results in a reduction in peak rates of runoff from the subject site when compared to pre- development conditions for the 2-, 10-, 25- and 100-year storm frequencies. In addition, the proposed best management practices will result in an effective removal of total suspended solids from the post-development runoff. The pre-development versus post-development stormwater discharge comparisons are contained in Table 5.1 below: Table 1.1: Design Point Peak Runoff Rate Summary Point of 2-Year Storm 10-Year Storm 25-Year Storm 100-Year Storm Analysis Pre Post A Pre Post A Pre Post A Pre Post A DPI 6.34 6.30 -0.04 10.17 10.16 -0.01 13.07 13.05 -0.02 18.89 18.28 -0.61 *Flows are represented in cubic feet per second(cfs) As outlined in the table above, the proposed stormwater management system as designed will provide a decrease in peak rates of runoff from the proposed facility for the 2-, 10-, 25- and 100- year storm events. Under the proposed project, an extensive stormwater system will be installed which will provide treatment, infiltration and peak rate attenuation while also retaining the runoff from most storm events on the site. As further described above, the project meets, or exceeds the MADEP Stormwater Management Standards. -14- APPENDIX A: MASSACHUSETTS STORMWATER MANAGEMENT CHECKLIST LiMassachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program ll Checklist for Stormwater Report A. Introduction Important:When A Stormwater Report must be submitted with the Notice of Intent permit application to document filling out forms compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for on the computer, (which h h hi Report R t St e Stormwater e wc sou provide more substantive and detailed information use only the tab the P p ) but is offered key to move your here as a tool to help the applicant organize their Stormwater Management documentation for their cursor-do not Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, use the return the Stormwater Report must contain the engineering computations and supporting information set forth in key. 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.' 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. 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. M201051-MA Stormwater Checklist.doc•04/01/08 Stormwater Report Checklist•Page 1 of 8 LiMassachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program ll 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 G rn y ;5 4 L10 ti{G 5/6/21 Sign a and e 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 M201051-MA Stormwater Checklist.doc•04/01/08 Stormwater Report Checklist•Page 2 of 8 LiMassachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program ll 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. M201051-MA Stormwater Checklist.doc•04/01/08 Stormwater Report Checklist•Page 3 of 8 LiMassachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program ll 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 Field' ® 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. 21 E 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. 21 E site or a solid waste landfill and a mounding analysis is included. 80%TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used. M201051-MA Stormwater Checklist.doc•04/01/08 Stormwater Report Checklist•Page 4 of 8 LiMassachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program ll 1� 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. M201051-MA Stormwater Checklist.doc•04/01/08 Stormwater Report Checklist•Page 5 of 8 LiMassachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program ll 1� Checklist for Stormwater Report Checklist (continued) Standard 4: Water Quality(continued) ® The BMP is sized (and calculations provided) based on: ® The '/2"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. M201051-MA Stormwater Checklist.doc•04/01/08 Stormwater Report Checklist•Page 6 of 8 LiMassachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program ll 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. M201051-MA Stormwater Checklist.doc•04/01/08 Stormwater Report Checklist•Page 7 of 8 LiMassachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program ll 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. M201051-MA Stormwater Checklist.doc•04/01/08 Stormwater Report Checklist•Page 8 of 8 APPENDIX B: PROJECT LOCATION MAPS ➢ USGS MAP ➢ FEMA FIRMETTE 10 17 kv FSr 20 N\i $ +�0 1111111\i o M /y y wat rtOWll h° Q h ' STUo y� o ° �' W ' E � A s Bemis AC.ON STv 3� �G� {�c�J 9l�PF yA�Z 1 Com S 1�SSttree rL N °[and T CALIFOR I SITE s.T h puncture J v -� R�FR Nonantum 20` Sy°FST t T AA Newton C.drner �4? �� � oO�P � •c` lip BOyOSTT _ J FR'R° T`les R1Vg\ \y� � �� NONANTUM.RD- 50 ST A - - SNINOtON " 700 O VERAO \ / ) 50 N A /L 4�k a 1 EW TONVLF CG NST / u � o — 50 T N C v,A,m l�t Id0•. J' S FFE R0 0 ANTUM ST� BR-� Ahp 150\ CABOTST > 3. Z PO.. OfONR y Qy� �NU �a E x EST P J Q\ p .SL l S 0 KIRKSTALL-Rp P� 9 o OVON l BR KET PC Pansh 15D R- c A< < D ft � ' P I-UP y„hs �w o oA vVaban )) PoltYl o �aRO S Oo ti5p� I\, i -wergr \ s'' �� COMMONWEA'TH AVE Bost n Newton'G m �o �Q� 1� PJ G� MoNq° College ct PLEA A— ST _ ■ Newton.Center _ _ _ USGS MAP t ` 64 PLEASANT STREET TOWN OF WATERTOWN, MASSACHUSETTS Institutioi Crystal Hil MIDDLESEX COUNTY \� h LdkB Collrew ege INDUNCKLEE Ando Thee PREPARED BY 0 0�Rp P AP A Scho � BOHLER // • C9G .w..fi._\ >� rz H glila1. -41- \c National Flood Hazard Layer FIRMette FEMA Legend 71°11'38"W 42°22'10"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT • Without Base Flood Elevation(BFE) A . Zone A,V,A99 SPECIAL FLOOD With BFE or Depth Zone AE,AO,AH.Ve.AR 'i J HAZARD AREAS Regulatory Floodway 7 0.2%Annual Chance Flood Hazard,Areas 1 j ' of 1%annual chance flood with average depth less than one foot or with drainage Y y � � areas of less than one square mile zone x Future Conditions 1%Annual Chance Flood Hazard zone x Area with Reduced Flood Risk due to OTHER AREAS OF Levee.See Notes.zone AREA OF MININIJ4L FLD HAZARD f FLOOD HAZARD �� Area with Flood Risk due to LeveeZoneD Zorn'' + ••+ NO SCREEN Area of Minimal Flood Hazard zonex c I _ + *• Q Effective LOMRs R OTHER AREAS Area of Undetermined Flood Hazard zone } , GENERAL '---- Channel,Culvert,or Storm Sewer 4 STRUCTURES IIIIIII Levee,Dike,or Floodwall � y A01 V Cross Sections with 1%Annual Chance Water Surface Elevation Z' WE o atertoivn � s- - - Coastal Transect ^-^^-5n— Base Flood Elevation Line(BFE) Limit of Study Jurisdiction Boundary — Coastal Transect Baseline OTHER _ Profile Baseline FEATURES Hydrographic Feature Digital Data Available N �• ^+wl��" No Digital Data Available MAP PANELS Unmapped • n i �f The pin displayed on the map is an approximate .s rt point selected by the user and does not represent e ' an authoritative property location. t ?t This map complies with FEMA's standards for the use of r �•• digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap y • r accuracy standards The flood hazard information is derived directly from the w authoritative NFHL web services provided by FEMA.This map * t ' was exported on 4/28/2021 at 12:25 PM and does not reflect changes or amendments subsequent to this date and y • # . time.The NFHL and effective information may change or - become superseded by new data over time. This map image is void if the one or more of the following map ► ly elements do not appear:basemap imagery,flood zone labels, ,r legend,scale bar,map creation date,community identifiers, AIL I c 71°S1'W 42°21'43"N FIRM panel number,and FIRM effective date.Map images for Feet 1:V 000 unmapped and unmodernized areas cannot be used for 0 250 500 1,000 1,500 2,000 regulatory purposes. Basemap:USGS National Map:Orthoimagery.Data refreshed October,2020 APPENDIX C: SOIL AND WETLAND INFORMATION ➢ NCRS CUSTOM SOIL RESOURCE REPORT ➢ REPORT OF GEOTECHNICAL INVESTIGATION Hydrologic Soil Group—Middlesex County,Massachusetts 3 _ (64 Pleasant) o 319430 319520 319610 319700 319790 3198W 319970 320060 320150 320240 42°22'3"N i i . i � 42°22'3"N a A f.. _ ALI , v Ail i 20 OC�3 •x - Soil Map may n.ot be val,idl'ata+his 5 al-. ��I ,• • \\' 42°21'45'INo .T ~51 i! �. -- i 42°21'45"N —a 319430 319520 319610 319700 319790 319880 319970 320060 320150 320240 3 3 Map Scale:1:4,040 if printed on A landscape(11"x 8.5")sheet. o P1eters N 0 50 101 200 300 Feet 0 150 300 600 900 Map projection:Web Mercator Comer coordinates:WGS84 Edge tics:UTM Zone 19N WGS84 G}DA Natural Resources Web Soil Survey 5/3/2021 Conservation Service National Cooperative Soil Survey Page 1 of 4 Hydrologic Soil Group—Middlesex County, Massachusetts (64 Pleasant) MAP LEGEND MAP INFORMATION Area of Interest(AOI) p C The soil surveys that comprise your AOI were mapped at Area of Interest(A01) 0 C/D 1:25,000. Soils D Warning:Soil Map may not be valid at this scale. Soil Rating Polygons � A p Not rated or not available Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil 0 A/D Water Features line placement.The maps do not show the small areas of Streams and Canals contrasting soils that could have been shown at a more detailed 0 B scale. Transportation 0 B/D Rails Please rely on the bar scale on each map sheet for map 0 C measurements. '.,,r Interstate Highways 0 C/D US Routes Source of Map: Natural Resources Conservation Service Web Soil Survey URL: 0 D Major Roads Coordinate System: Web Mercator(EPSG:3857) Not rated or not available Local Roads Maps from the Web Soil Survey are based on the Web Mercator Soil Rating Lines Background projection,which preserves direction and shape but distorts q distance and area.A projection that preserves area,such as the ® Aerial Photography Albers equal-area conic projection,should be used if more • A/D accurate calculations of distance or area are required. +'* B This product is generated from the USDA-NRCS certified data as B/D of the version date(s)listed below. x C Soil Survey Area: Middlesex County, Massachusetts Survey Area Data: Version 20,Jun 9,2020 0 C/D Soil map units are labeled(as space allows)for map scales r D 1:50,000 or larger. r Not rated or not available Date(s)aerial images were photographed: Sep 25,2020—Oct 4, 2020 Soil Rating Points p A The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background p A/D imagery displayed on these maps.As a result,some minor B shifting of map unit boundaries may be evident. B/D UU� Natural Resources Web Soil Survey 5/3/2021 � Conservation Service National Cooperative Soil Survey Page 2 of 4 Hydrologic Soil Group—Middlesex County,Massachusetts 64 Pleasant Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 1 Water 4.3 7.3% 602 Urban land 43.4 73.3% 626B Merrimac-Urban land A 11.2 18.9% complex,0 to 8 percent slopes 629C Canton-Charlton-Urban A 0.3 0.5% land complex,3 to 15 percent slopes Totals for Area of Interest 59.2 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential)when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential)when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. usDA Natural Resources Web Soil Survey 5/3/2021 Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group—Middlesex County,Massachusetts 64 Pleasant Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff.-None Specified Tie-break Rule: Higher uSDA Natural Resources Web Soil Survey 5/3/2021 Conservation Service National Cooperative Soil Survey Page 4 of 4 SANBORN 11 HEAD l SuAdin Trust.En ineerin Success. 9 9 4 MEMORANDUM To: Mr. Morgan Pierson, Ms. Esther Chung Byun and Ms.Jen Rosenberg- Berkeley Investments From: Quincy Pratt, P.E.and Stan Sadkowski, P.E. - Sanborn Head&Associates File: 4928.00 Date: March 19, 2021 Re: Geotechnical Design Recommendations 64 Pleasant Street,Watertown, Massachusetts cc: Mr.John Sullivan, Mr.John Carlson, Ms. Kristen O'Gorman, Mr. Dan Connolly- SGA Mr. Brett Goldstein, PE-Goldstein-Milano Sanborn, Head&Associates, Inc. (Sanborn Head) has prepared this geotechnical engineering design memorandum to Berkeley Investments (Berkeley)to summarize our subsurface investigations at the Site and provide our geotechnical design recommendations for the preparation of building foundations in support of the proposed renovations at 64 Pleasant Street in Watertown, Massachusetts (the Site). This memorandum is subject to the limitations include in Attachment A. SITE DESCRIPTION AND PROJECT UNDERSTANDING The Site is located west of Watertown Square, in Watertown, Massachusetts and is bounded by Pleasant Street to the north,Brooks Street to the east,the Massachusetts Department of Conservation and Recreation (DCR) Dealtry Memorial Pool to the west, and The Charles River and DCR's Charles River Greenway to the south. The Site currently consist of five (5) 2- to 3- story contiguous office buildings,with associated parking areas.Based on available historical satellite imagery and Sanborn Maps, buildings were present at the Site prior to 1884, and have undergone several modifications and use changes prior to their current use as office space. The existing buildings are designated as Buildings A, B, B2, C, and D. Sanborn Head subdivided the designation for B2 into B2.1 and B2.2 to assist in our descriptions of the subsurface observations below the existing slab. The approximate locations of the building and their designations are shown on Figure 1. Based on the "Existing Conditions" plan, prepared by Feldman Land Surveyors (FLS) dated January 16, 2021, the elevations in the existing parking areas and drive isles vary between approximate elevation (El.) 16 feet along Pleasant Street down to approximate El. 8.0 feet at the lowest point in the parking areas Building B and Building C.A steeper slope is present south of Buildings A, C and D along the banks of the Charles River where the slope drops from El. 9 feet at the top of the bank to the Charles River. The elevation of the Charles River generally varies between El. 2.12 feet and El. 2.62 feet,based on data obtained from the United States Geological Survey(USGS) Charles River Gage Location at First Street in Cambridge,MA;the maximum recorded elevation of the river is El.3.2 feet. Elevations described herein references the North American Vertical Datum of 1988 (NAVD88). We understand the project includes converting the existing office space into a lab and office space. Based on preliminary test fit drawings provided by SGA dated March 3, 2021,the proposed concept includes lowering the existing lowest level floor in Building A, B2, and C by two (2) feet, and raising the floor in a portion of Building B by approximately 1.9 feet. SANBORN, HEAD& ASSOCIATES, INC. www.sanbornhead.rom March 19,2021 Page 2 20210319 64 Pleasant St-GT Memo.docx 4928.00 Additionally, we understand some of the existing columns will be removed to create a more open floor plan, and new columns may be needed to support modifications to the HVAC dunnage on the roof. The number and locations of the column removal and new columns are not currently known; however, based on conversations with the project structural engineer, Goldstein-Milano, individual column loads are not anticipated to exceed 100 kips and the exterior foundation walls will not be designed to carry more weight than the current loading. SUBSURFACE EXPLORATIONS AND SUBSURFACE CONDITIONS Sanborn Head performed multiple subsurface investigation at the and reviewed the available subsurface exploration performed by other. Subsurface exploration consisted of a combination of test borings, test pit (both inside and outside the existing buildings), and subsurface probes to evaluate the height of the crawlspace below the 15Y floor slab. Boring logs from test borings and test pits are in Attachment B. A summary of the subsurface probe data is in Table 2. Based on our subsurface explorations and our observations in the crawlspaces of Building A,B2,and C the subsurface conditions are as follows: Lowest Level Floor, Crawlspace and Foundation Observations: The lowest-level floor and crawlspace observations were performed by Sanborn Head, where accessible,in Buildings A,B2,and C.Additionally,the existing building foundations were observed in TP-1 through TP-5. Our observations of the crawlspaces and existing foundations are as follows: ■ Building A: ❑ Flooring: Approximately 2-inch-thick wooden flooring supported by 2" x 10" wooden joists. A concrete leveling pad and a raised false floor was observed in the areas shown on Figure 1. ❑ Crawlspace: The height of the crawlspace varied between approximately 2.3 -3.8 feet from the top of the existing floor to the soil subgrade.The correlating soil subgrade elevations vary between approximately EL. 7.8 and 9.3 feet. ❑ Foundations: The columns and floor joists terminate on a formed concrete grade beam (bearing on fill soils). The column connections were not visible. Unformed footings were observed below the grade beams at the TP-2 and TP-3 locations. A mortared field stone (perimeter) foundation wall was observed at the TP-2. See test pit logs TP-2 and TP-3 for observed Building A existing foundation conditions. ■ Building B: See log for TP-5 for exterior foundation wall observations. No crawlspace or flooring data were collected by Sanborn Head. ■ Building B2.1: ❑ Flooring: A concrete slab was observed from the crawlspace and below the carpet. The slab thickness is estimated at 6 inches but will need to be confirmed prior to demolition.The slab is supported on a combination of wooden joists and granite piers of varying dimensions. ❑ Crawlspace:The height of the crawlspace varied between approximately 3.5 and 6.5 feet from the top of the existing floor. The correlating soil subgrade elevations is between approximately EL. 5.4 and El. 8.4 feet. ❑ Foundations: The columns are supported on approximately 12" x 12" mortared brick piers that extend below the soil subgrade. Footings were not observed. SAN BORN HEAL March 19,2021 Page 3 20210319 64 Pleasant St-GT Memo.docx 4928.00 ❑ Other notes: A former underground culvert was observed extending beyond the eastern extent of the building at the approximate location shown in the figure. ■ Building B2.2 ❑ Flooring: A concrete slab was observed from the crawl space and below the carpet.The slab thickness is estimated at 6 inches and will need to be confirmed prior to demolition.The slab is supported by formed concrete beams. ❑ Crawlspace:The height of the crawlspace varied between approximately 7 and 8feet from the top of the existing floor. The correlating soil subgrade elevations is between approximately EL. 3.4 and 4.4 feet. ❑ Foundations: The columns are supported on approximately 16" x 16" granite piers that extend below the soil subgrade. Footings were not observed. ❑ Other notes: Remnant piping from old mill equipment was observed throughout the crawlspace including an approximately 10-12-foot diameter steel mill wheel as shown on the attached figure. ■ Building C: ❑ Flooring: The flooring consists of an approximate 2-inch-thick plywood floorboards supported by 2" x 22" wooden truss joint. A portion of the flooring was topped with a 2.5- inch-thick concrete leveling slab. The estimated floor thickness is 4.5 inches for the portion where concrete leveling slab is present. A 1-inch-thick floorboard was observed in TP-1. ❑ Crawlspace: The height of the crawlspace varied between 3.4-4.7 feet from the top of the existing floor.The correlating soil subgrade elevations is between EL. 6,8 and 8.1 feet. ❑ Foundations: For exterior foundation wall observation see TP-1 and TP-4. ❑ Other notes: Construction debris such as bricks, concrete, and polyethylene sheeting were observed above the subgrade in the crawlspace as noted on the logs. ■ Building D: No flooring,crawlspace, or foundation data were collected by Sanborn Head. Photograph of our observations in the crawlspaces below Building A,B2,and C and in the test pit are included in Attachment C. Subsurface Conditions Observed at Exterior Explorations The following subsurface conditions were observed in the test pits and borings performed outside the existing buildings. ■ Fill:An approximately 6-to at least 8-foot-thick layer of variable-density,fill was encountered in the borings and test pits.The full thickness of the fill layer was not penetrated in test pits due to their proximity to the building's existing foundations.The fill consists of fine to coarse sand with varying amounts of silt and gravel,and non-soil constituents such as brick,wood,glass,and ash. • Natural Sand and Gravel:A natural sand and gravel layer was encountered below the fill layer. The top of the layer was encountered at depths ranging from approximately 6 to 8 feet bgs (or approximately between El. 1.0 to 5.0 feet). The natural sand and gravel layer generally consists medium dense to dense,fine to coarse sand with varying amounts of gravel and silt. SAN BORN HEAL March 19,2021 Page 4 20210319 64 Pleasant St-GT Memo.docx 4928.00 ■ Glacial Till: Glacial till was encountered below the natural sand and gravel layer in boring SH-1. The top of the glacial till layer was encountered approximately 20 feet below ground surface (or approximately EL. -11.0 feet). The glacial till consists of very dense and very stiff fine to coarse sand and silt and trace gravel. Stabilized groundwater measurements were collected by Sanborn Head from on-site groundwater monitoring wells on January 19, 2021. Based on our measurements,groundwater was encountered between approximately 5.5 and 5.9 feet bgs, which corresponds to approximately between EL. 5.6 feet and El.3.1 feet. Based on the stabilized groundwater readings,the groundwater flows from north to south towards the Charles River. Groundwater measurement are provided on the logs and stabilized groundwater data are summarized in Table 2. It should be noted that groundwater levels will vary depending on seasonal variations in temperature, precipitation and influence from nearby structures or subsurface utilities, and other factors that differ from conditions at the time the measurements were made. GEOTECHNICAL CONSIDERATIONS AND RECOMMENDATIONS Based on the subsurface conditions at the Site,we recommend the following be considered for design of the building slabs and foundations. Foundation Recommendations Our recommendations for foundations at new and existing columns are below. Foundations should be design to limit total settlement to 1 inch and differential settlement of 0.5" between adjacent columns. At new column locations: • Spread Footings: New columns should be supported by spread footings bearing on the natural, inorganic sand and gravel layer or bearing on compacted structural fill placed over the natural, inorganic,granular soils. The existing fill soil is unsuitable to support new foundations.Based on the subsurface data,we anticipated the sand and gravel layer will be encountered between El. 1.0 and El. 5.0 feet in the building.Where spread footings are proposed,dewatering will be required in the excavation to allow for construction of spread footings in the dry. New foundations should be proportioned based on a net allowable bearing capacity of 3 kips per square foot(KSF). • Helical Piles:As an alternative to spread footings,new columns could also be supported pile caps and helical piles. Helical piles should be designed based on an allowable capacity of 30 kips,where the helical piles bear within the natural, sand and gravel layer. At existing column locations: • Existing columns where the increase in gravity loads is less than 5%: The International Existing Building Code (IEBC) allows increasing the design gravity capacity of up to 5%without requiring modifications to the exiting foundation.At locations where new columns loads are less than 5%more than the existing gravity load,no foundation modifications are required. • Existing column loads where the increase in gravity loads is greater than 5%: Where column loads will increase by greater than 5% (of current load) at foundations to remain, we SAN BORN H EALI March 19,2021 Page 5 20210319 64 Pleasant St-GT Memo.docx 4928.00 recommend pile caps and helical piles be constructed to support the new column loads. Helical piles should be designed with an allowable capacity of 30 kips,where the helical piles bear within the natural, inorganic, granular soils. At these locations, the existing column will need to be temporarily supported while the new foundation is constructed. Alternatively, the existing footing could be removed, and a new (larger) footing could be constructed as described herein to support the new load(s). Based on our observations during test pitting, we do not recommend relying on the existing bearing soil to provide increased support where foundations are retrofitted as it appears several footings are currently bearing on fill soil. Slab Recommendations-Building A and Building C Based in the subsurface data and the proposed finished floor elevation (FFE),the existing grade will need to be raised approximately 2.7 feet in Building C. Sanborn Head recommends two possible approaches (conditional to contractor pricing) be considered for achieving the proposed finished floor elevation. • Slab-on-grade: Due to the presence of variable density fill in the crawlspace,the existing fill material is not suitable to support a slab-on-grade in its current condition. To make the soil suitable for slab support,we recommend the existing fill be excavated to a minimum of four (4) feet below the proposed FFE (approximately El. 5.9 feet). The bottom of the excavation should be proof rolled with a vibratory plate compactor until visibly firm and stable. The excavated fill (that is geotechnically suitable) can be replaced and compacted to raise the grade. Fill should be placed in 12-inch-thick lifts and compacted to at least 95%it's maximum dry density, as determined by ASTM D1557 Method C (Modified Proctor),to one foot below the bottom of slab elevation.The final 12 inches of fill should consist of a base course layer of dense-graded crushed stone directly below the slab-on-grade. Based on the test pits performed inside the building, pockets of ash, wood and other debris were observed in the fill material below Building A. Material containing ash and other debris is not considered geotechnical suitable for reuse. We estimate at least 25% of the material below Building A and C may not be suitable for re-use as raise-in-grade fill below the slab-on- grade. The contractor should perform a cut-fill analysis to determine the actual quantity of excess material that will require off-site disposal. If this alternative is selected, we recommend performing additional exploration in the Building A and C to identify the extent of the geotechnically unsuitably material and to collect pre-characterization samples to inform the quantity and chemical characteristics of material requiring off-site disposal. • Structural Slab: As an alternative to a slab-on-grade, a structural slab could be constructed to support future slab loads. The structural slab thickness and grade beams should be designed by the structural engineer. The grade beams should be supported on helical piles with a 30-kip capacity as specified in the foundation section above.The structural slab would be self-supported between the helical piles and as such the subgrade could consist of the existing urban fill material. The subgrade should be compacted and level to allow for a firm and stable working surface prior to placing the moisture barrier,slab rebar,and concrete. The benefits to the structural slab include eliminating over-excavation, replacement and disposal of existing fill material. Additionally, excess cut material generated by pile cap and footing excavations could be used to raise the grade below the structural slabs and be used as a discrete base course layer for the slab subgrade,provided the material is workable. SAN BORN HEAL March 19,2021 Page 6 20210319 64 Pleasant St-GT Memo.docx 4928.00 Where fill is required to raise the grade inside the building to a level that exceeds the existing grade outside the building, the existing foundation walls should be evaluated for their ability to support lateral pressures from the additional fil material.Based on the proposed FFE's and the existing grade, the southern foundation walls of Building A and C should be evaluated fir their ability to resist the additional earth pressures. Slab Recommendations-Building B2 Based in the subsurface data, and the proposed FFE in Building B2 is between approximately 1 and 6 feet above the existing soil subgrade in Building B2. As such, we recommend the new slab be designed as a structural slab supported by the existing or new foundations. The structural slab thickness and supporting joists and/or beams should be design by the structural engineer. Seismic Design Based on the proposed building location and elevations, Site Class D is recommended for the proposed building as defined by the Massachusetts State Building Code,9th Edition. Design Groundwater Elevation For preliminary design purposes, we recommend the design groundwater elevation be assumed as El. 5.5 feet. This recommendation is subject to change as additional, temporal groundwater measurements are needed to finalize the design assumption. We trust this memorandum meets the current project needs. Please call us at 857-327-9730if you have any questions regarding this memorandum. Very truly yours, SANBORN,HEAD&ASSOCIATES,INC. Qui7�ratt P.E. Stan S. Sadkowski, P.E. Senior Project Manager Senior Vice President QP/SSS: qp Encl. Figure 1 - Exploration Location Plan Table 1 -Subsurface Probe Data Table 2 - Groundwater Data Attachment A- Limitations Attachment B -Subsurface Exploration Logs Attachment C - Photographic Log \\bosservl\shdata\SHDATA\4900s\4928.00\Source Files\2_GT Memo\20210319 64 Pleasant St-GT Memo.docx SAN BORN HEAL FIGURE SANBORN 1111 HEAD NOTES: 1. THE BASE MAP WAS DRAWN FROM A PLAN ENTITLED,"EXISTING CONDITIONS PLAN" PREPARED BY FELDMAN LAND BOSTO OF SURVEYORS DATED O N,MA 01/16/2021 WITH AN ORIGINAL SCALE OF V=20'. ® ® 2. THE PROPOSED SITE FEATURES WERE DRAWN FROM APLAN ENTITLED, .y � " ,, AaiA "A101.DWG"AND PROVIDED TO SANBORN HEAD BY BERKELEY INVESTMENTS ON JANUARY 25,2021. Y RFET 3. EXPLORATIONS DESIGNATED SH-101W,AND SH-102THROUGH SH-104 WERE ADVANCED BY CRAWFORD DRILLING SERVICES,L-C.(CDS)OF WESTMINSTER, c o" \ "° � T r�-Q� MAAND OBSERVED BY SANBORN HEAD ON JANUARY 18,2021. / • ns�v 9es JI'. sR/ayn,° 5 4. TEST PITS DESIGNATED TP-1 THROUGH TP-3 WERE EXCAVATED BY CHUTEHALL 4 �o Q �� a CONSTRUCTION(CHUTEHALL)OF CAMBRIDGE,MA AND OBSERVED BY SANBORN 'A'oS °P "`"�� ,� HEAD BETWEEN JANUARY 18 AND JANUARY 21,2021. — •m I ++• TEST PITS DESIGNATED TP 4 THROUGH TP 5 WERE EXCAVATED BY F.E. FRENCH CONSTRUCTION INC.(FEE)OF BELMONT,MAAND OBSERVED BY 7 ,*R / i — u y O — V A SANBORN HEAD ON JANUARY 22,2021. y w.s �,-: TP-5 -- �� p-+.. :'..•a N f ——— 6. INTERIOR PROBES DESIGNATED A-1 THROUGH A-11,B-1 THROUGH B-14,AND C-1 THROUGH C-8 WERE COMPLETED BY SANBORN HEAD BETWEEN JANUARY a°'•'° — y, 18 AND JANUARY 22,2021. APPROXIMATE LOCATION WHERE _ BUILDING B2.1 7. MONITORING WELLS AND BORINGS DESIGNATED IES-1 THROUGH IES-7WERE / r — — ---- FORMER STEEL MILL WHEEL WAS w WERE INSTALLED BY IES,INC.OF LYNNFIELD,MA IN MARCH 2O17. -�;� � p/ _� � p CURRENT FFE:11.9' �� OBSERVED ———— —— --� o V i�✓�' N r T A-9 \ ' ? _ I 15` PROPOSED FEE:9.9' \ � I / '�\ APPROXIMATE LOCATIONS OF EXPLORATIONS ARE BASED ON TAPED 6` FSH-102 \ �' MEASUREMENTS MADE IN THE FIELD RELATIVE TO PROMINENT SITE BUILDING B �a - - / \\�� Oho• p FEATURES.THIS DATA SHOULD BE CONSIDERED ACCURATE ONLY TO THE / CURRENT FEE:11.9' ® ® � o IES-4 DEGREE IMPLIED BY THE METHOD USED. A-5 PROPOSED FEE:11.9'-13.8' '1D L°` SH-103 CS-2 + A-10� - .. LEGEND BUILDING A , ��/ d - ® 3H-, i /7? APPROXIMATE LOCATION AND DESIGNATION OF BORINGS A-2 /�G* A-6 B-12 OBSERVED BY SANBORN HEAD(APRIL 2019) � CURRENT FEE:11.57' � � )� ka. '�`y PROPOSED FEE:9.9' -� 1 A-4 -'"`"A-11 - I B-14 B-13 - B 1 r 4 SH-1W !!! 4 BUILDING B2.2 APPROXIMATE LOCATION AND DESIGNATION OF BORINGS WARro 1 / cT \ A-3 A_7 �� B_1 I B�Q,,CS-4 CURRENT FFE:11.9' OBSERVED BY SANBORN HEAD(JANUARY 18,2021) WN pqM ® SH-1 �, P_2 _ / '�, .l d �� B.-3 PROPOSED FEE:9.9' IES-1 APPROXIMATE LOCATION AND DESIGNATION OF BORINGS AND L IEs-s B 9 g_ / MONITORING WELLS INSTALLED BY IES,INC.(MARCH 2O17) ��� e,° e_zs v_,w * .• ES- / arT oiNiN�\ �+u B 4 TP 1 APPROXIMATE LOCATION AND DESIGNATION OF EXTERIOR TEST 3 PITS OBSERVED BY SANBORN HEAD 22,2021) B_6 JANUARY �� ( E gw O TP-4 APPROXIMATE LOCATION AND DESIGNATION OF INTERIOR TEST APPROXIMATE EXTENT OF RAISED FLOOR s / APPROXIMATE LOCATION OF FORMER � SUBSURFACE CUVLERT. � PITS OBSERVED BY SANBORN HEAD(JANUARY 18,22,2021) \ IES-7ry \ / \0\\ ®� / \ d 4 E A-1 APPROXIMATE LOCATION AND DESIGNATION OF INTERIOR PROBES APPROXIMATE EXTENT WHERE b \\ \ \ \ C'S , COMPLETED BY SANBRON HEAD(JANUARY 18-22,2021) - CONCRETE LEVELING PADS WERE \.\� \\\\ - / / •�J�gti OBSERVED ABOVE FLOORBOARDS. \�� \~\\~\ C 6 �" c�0 4\ APPROXIMATE LOCATION AND DESIGNATION OF CRAWLSPACE ac�y11 HATCHES TP-4� I IES-2 BUILDING C CURRENT FEE:11.44 PROPOSED FEE:9.9 zr \ BUILDING D DRAWN BY: D.DOMBROWSKY GEOTECHNICAL DATA TRANSMITTAL PROJECT NUMBER: Tu DESIGNED BY: J.SOUSA 64 PLEASANT STREET 4928.00 c � SANBORN HEAD A� GRAPHICAL SCALE I WATERTOWN,MASSACHUSETTS iiilll li I REVIEWED BY: Q.PRATT 30' i6' 0' 30' 60' PROJECTMGR: Q.PRATT SHEET NUMBER: PIC: S.SADKOWSKI EXPLORATION LOCATION PLAN g a DATE: MARCH 2O21 NO DATE DESCRIPTION BY TABLES SANBORN 1111 HEAD TABLE 2 Groundwater Elevation Table Geotechnical Memorandum 64 Pleasant Street,Watertown,Massachusetts 4928.00 Exploration Reference Reference Point Measured Depth to Groundwater Designation Point Elevation(ft) Groundwater From Elevation(ft) Date Reference Point (ft) SH-101W GS 11.5 5.9 5.6 IES-1 GS 9.0 5.5 3.5 1/19/2021 1 IES-2 GS 9.0 5.5 3.5 1 IES-3 GS 9.0 5.8 3.3 1 IES-4 GS 11.0 5.9 5.1 Notes: 1. Depth to groundwater was measured by Sanborn Head on the date shown. 2. Groundwater Elevation is given in feet and referenced to North American Vertical Datum of 1988. 3. Ground surface elevations were estimated by Sanborn Head based on the site grading plan provided by Feldman Land Surveyors (rounded to the nearest 0.5 feet). 4.Abbreviations: GS = Ground Surface P:\4900s\4928.00\Work\Logs Page 1 of 1 Sanborn Head and Associates Inc. ATTACHMENT A LIMITATIONS SANBORN 1111 HEAD ATTACHMENT A LIMITATIONS Explorations 1. The analyses, recommendations, and designs submitted in this memorandum are based in part on the data obtained from subsurface explorations. The nature and extent of variations between these explorations may not become evident until construction. If variations then appear evident, it will be necessary to re-evaluate the recommendations of this memorandum. 2. The generalized soil profile described in the text is intended to convey trends in subsurface conditions.The boundaries between strata are approximate and idealized, and have been developed by interpretation of widely spaced explorations and samples; actual soil transitions may be more or less gradual than indicated. For specific information, refer to the subsurface exploration logs. 3. Water level readings have been made in the drill holes at the times and under the conditions stated on the exploration logs. These data have been reviewed and interpretations have been made in the text of this report. However, it must be noted that fluctuations in the level of the groundwater may occur due to variations in rainfall, temperature, and other factors differing from those occurring at the time measurements were made. Review 4. In the event that any changes in the nature, design, or location of the proposed structure are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of the memorandum modified or verified in writing by Sanborn Head. Construction 5. It is recommended that this firm be retained to provide soil engineering services during the excavation and earthwork construction phases of the work. This is to observe compliance with the design concepts, specifications, or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to the start of construction. Use of Report 6. This memorandum has been prepared for the exclusive use of Berkeley Investments for the redevelopment and construction at the 64 Pleasant Street, Watertown, Massachusetts project in accordance with generally accepted soil and foundation engineering practices. No other warranty, expressed or implied, is made. 7. This geotechnical memorandum has been prepared for this project by Sanborn Head for design purposes only. Contractors using this memorandum to prepare a bid for site work or foundation construction acknowledge that its scope is limited to design considerations only. P:\4900s\4928.00\Source Files\2_GT Memo\Attachment A-Limitations\Limitations.docx SANBORN 1111 HEAD ATTACHMENT B SUBSURFACE EXPLORATION LOGS SANBORN 1111 HEAD Project:Sasaki Associates Log of Boring SH-1 SANBORN 1111 HEAD Location:Watertown,MA Project No.:4557.00 Ground Elevation:9±feet Datum:NAVD 1988 Sanborn,Head&Associates,Inc. Drilling Method:4"Drive and Wash,CME 45 Track Rig Sampling Method:2"O.D.Split Spoon,Automatic Hammer Groundwater Readings Depth Depth Depth Stab. Date Time to Water Ref.Pt. of Casing of Hole Time Drilling Company:Geologic Earth Exploration,Inc. 04/02/19 10:55 7.05' Ground Surface 29' 30.6' None Foreman:T.Grenier Date Started:04/02/19 Date Finished:04/02/19 Logged By:A.Coen Checked By:A.Blomeke Sample Information Stratum Depth Spoon Pen/ Field Geologic Description Remarks (ftl Sample Depth Blows Rec Testing Log Description g p No. (ft) ner 6 in (in) Data 4, ASPHALT (0 to 05):ASPHALT. S-1 0.5-2 14 18/14 0'5 S-1 (0.5 to 2'):Dense,dark brown,fine to coarse 27 i SAND,little Gravel,little Silt.Moist.FILL. - 19 2 S-2 2-4 19 24/18 S-2(2 to 4'):Dense,dark brown,fine to coarse 16 I SAND,little Gravel,little Silt.Moist.FILL. 18 _ 14 " I 4 S-3 4-6 8 24/4 FILL S-3(4 to 6'):Loose,gray/brown,fine to coarse Drill wash flushed out fines — 5 I GRAVEL,little Sand.Moist.FILL. through gravel. 3 - 2 " I 6 S-4 6-8 9 24/11 S-4(6 to 8'):Very dense,brown,fine to coarse Increase in drilling effort observed — 16 \I SAND and Gravel,little Silt.Moist to wet.FILL. at approximately 6 feet. m _ 36 _ 16 " I a o S-5 8-10 9 24/6 S-5(8 to 10'):Medium dense,dark gray and �? 16 brown,fine to coarse SAND,little Gravel,little Silt. > _ 13 Wet. _ 19 LU z 10- 0 m 12— Increase in drilling effort observed — at approximately 12 feet. 0 w z 14— S-6 14-16 10 24/10 SAND S-6(14 to 16'):Medium dense,brown,fine to 0 10 coarse SAND,little Gravel,little Silt.Wet. m 7 z - - < 9 16- 0 J 0 18— — N a o S-7 19-21 24/8 21 S-7(19 to 21'):Very dense,gray/brown,fine to J 21 medium SAND,some Silt,trace Gravel.Wet. W20 46 42 -----20'----- Transition to glacial till at 20 feet. — 0 0. No recovery from 19-20 feet. m Y - - 0 a.Q. 6 22— (n ?Q GLACIAL TILL Increase in drilling effort observed a 24— Q. at approximately 23.5 feet. — 0 S-8 24-25.3 8 16/5 a'. S-8(24 to 25.3'):Very dense,gray/brown,fine to p 50 coarse SAND,some Silt,trace Gravel.Wet. _ 50/4" z a.Q. o m 9F— Sheet:1 of 2 Project:Sasaki Associates Log of Boring SH-1 SANBORN 1111 HEAD Location:Watertown,MA Project No.:4557.00 Ground Elevation:9±feet Datum:NAVD 1988 Sanborn,Head&Associates,Inc. Drilling Method:4"Drive and Wash,CME 45 Track Rig Sampling Method:2"O.D.Split Spoon,Automatic Hammer Groundwater Readings Depth Depth Depth Stab. Date Time to Water Ref.Pt. of Casing of Hole Time Drilling Company:Geologic Earth Exploration,Inc. 04/02/19 10:55 7.05' Ground Surface 29' 30.6' None Foreman:T.Grenier Date Started:04/02/19 Date Finished:04/02/19 Logged By:A.Coen Checked By:A.Blomeke Sample Information Stratum Depth Spoon Pen/ Field Geologic Description Remarks lftl Sample Depth Blows Rec Testing Log Description gis p ner 6 in (in) D&ta 26— — a' GLACIAL TILL 28— :l — aO -----29' --------------------- - S-9 29-31 5 24/8 a�7 S-9(29 to 31'):Very stiff,light brown,SILT and 7 Sand,trace Gravel.Wet. 30— 11 - 21 ' GLACIAL TILL 32— a 34— 4' — — — -- -- — o 5-10 34-34.4 100/5" 5/5 a� Goa TILL S-10(34 to 34.4'):Very dense,light brown,fine to 0 medium SAND and Silt.Wet. o - Boring terminated at 34.4 feet. - w zz 36— NOTES: — °m 1.Upon completion,the borehole was backfilled _ with drill cuttings and finished to existing grade _ with an asphalt patch. 0 N 38— — m J Q W Z 40— — K O in Z - - Q V) r 42— — 0 0 0 J 0 44— — N N a Cn - - 0 O J Z 46— — W O m Y - - 0 O 6 48— — v in - - 0 0 v a 50— — 0 0 J 0 - - Z 0C m F9— Sheet:2 of 2 Project:Berkley Investments Log of Monitoring Well SH-101W SA N B OR N 1111 HEAD Location:Watertown,MA Ground Elevation:12±feet Project No.:4928.00 Datum:NAVD88 Sanborn,Head&Associates,Inc. Drilling Method:Truck Mounted B57 Mobil Rig,4.25"O.D.Hollow Stem Augers Sampling Method:2"O.D.Split Spoon,Automatic Hammer Groundwater Readings Depth Depth Depth Stab. Date Time to Water Ref.Pt. of Casing of Hole Time Drilling Company:Crawford Drilling Services,LLC 01/18/21 09:00 6.52' Ground Surface 6' 8' 20 Minutes Foreman:J.Martinelli 01/19/21 08:50 5.94' Ground Surface Well Installed Well Installed 22 Hours Date Started:01/18/21 Date Finished:01/18/21 Logged By:J.Sousa Checked By:Q.Pratt Sample Information Stratum D(ft)h Sample No, Deft)h Spoon lows R c/ T sting Log Description Field Geologic Description Diagrlem Well Description oer 6 in (in) Data 0 �jsPHA�/PAVE: (0 to 0.5'):ASPHALT. 6"Dia.Flushmounted .. -----0.5------ Road Box Set in Concrete S-1 0.5-2 7 18/12 PID:ND S-1(0.5 to 2'):Loose,brown,fine to coarse SAND (0 to 1') - 5 and Gravel,trace Silt,few Glass pieces,few Brick 4 pieces.Moist.FILL. 2"Dia.Sch.40 PVC Riser I (0.5 to 6) 2 S-2 2-4 5 24/0 S-2(2 to 4'):Very loose,No Recovery. 3 I Soil Cuttings(1 to 4') 1 - 2 I S-3 4-6 3 24/4 PID:ND I FILL S-3(4 to 6'):Very loose,brown,fine to coarse SAND 1 and Gravel,some Silt,trace Ash,very few Brick Bentonite Chips(4 to 5') 2 i, pieces.Moist.FILL. 2"Dia.Sch.40 PVC Well - 9 I _ '. Screen(0.010"Slots)(5 to — 15') 6 S-4 6-8 2 24/4 PID:1.5 I S-4(6 to 8'):Very dense,brawn/black,fine to coarse — 1 ppmv SAND,some Silt,trace Gravel,very few Wood — 1 pieces,few Ash fragments.Moist to Wet.FILL. 1 I = 8 S-5 8-10 18 24/5 PID:ND 8 S-5(8 to 10'):Dense,brown,fine to coarse SAND 25 !• •.,4 R. and Gravel,trace Silt.Wet. 17 - r; 18 ~ 10— •' — Filter Sand(5 to 15') — S-6 10-12 27 24/12 PID:ND • S-6(10 to 12'):Medium dense,brown,fine to coarse 13 SAND and GRAVEL,trace Silt.Wet. o _ 13 u 12 z 12— •i� — z SAND& GRAVEL U) _ •: _ N w• m 14— - 0 " R w S-7 15-17 4 24/12 PID:ND !'!, S-7(15 to 17'):Medium dense,brown,fine to coarse = 2 ;•: SAND,some Gravel,trace Silt.Wet. � 9 0 16— 12 i�� Soil Cuttings(15 to 17') — m z :'•�. < '.r. - �� -----17------ Boring terminated at 17 feet.No refusal N encountered. 18— — $ NOTES: - 1.Soil Samples were screened for volatile organic - compounds(VOCs)using a Tiger Photoionization 0 Detector(PID)with a 10.6 eV lamp,calibrated to a 20— 100 parts per million by volume(ppmv) — isobutylene-in air standard using a response factor 0 of 1.0.Results are presented in ppmv;the typical 3 - detection limit is 1 ppmv.ND indicates not detected. - o NA indicates not available.the PID measures N relative levels of VOCs.Although PID screening v 22— cannot be used to directly quantify VOC — 0 concentrations or identify individual compounds,the 0 m results can serve as a relative indicator for the a - presence of VOCs. - 0 O 24— — z E O in - - Sheet:1 of 1 Project:Berkley Investments Log of Boring SH-102 SA N B OR N 1111 HEAD Location:Watertown,MA Ground Elevation:11±feet Project No.:4928.00 Datum:NAVD88 Sanborn,Head&Associates,Inc. Drilling Method:Truck Mounted B57 Mobil Rig,4.25"O.D.Hollow Stem Augers Sampling Method:2"O.D.Split Spoon,Automatic Hammer Groundwater Readings Depth Depth Depth Stab. Date Time to Water Ref.Pt. of Casing of Hole Time Drilling Company:Crawford Drilling Services,LLC 01/18/21 11:15 6.8' Ground Surface 6' 8' 20 Minutes Foreman:J.Martinelli Date Started:01/18/21 Date Finished:01/18/21 Logged By:J.Sousa Checked By:Q.Pratt Sample Information Stratum Depth Spoon Pen/ Field Geologic Description Remarks (ft) Sample Depth Blows Rec Testing Log Description g p No. (ft) oer 6 in (in) Data 0 ; ASP ALT (0 to 05):ASPHALT. S-1 0.5-2 4 18/3 PID:ND -0'S S-1(0.5 to 2'):Loose,brown/black,fine to coarse - 3 SAND and Gravel,trace Silt,trace Ash particles. - 2 I Moist.FILL. 2 S-2 2-4 2 24/0 ,V i S-2(2 to 4'):Very loose,No recovery.FILL. 1 � 1 I FILL S-3 4-6 2 24/5 PID:ND I S-3(4 to 6'):Loose,brown,fine to coarse SAND and 1 Gravel,some Silt,trace Ash particles,very few Brick 6 i, particles.Moist.FILL. _ 9 I S-4 6-8 12 24/7 PID:ND S-4(6 to 8'):Dense,brown,fine to coarse SAND /. 16 .�,� and GRAVEL,trace Silt.Moist to Wet. 15 •'' 14 - R�i 8 S-5 8-10 10 24/14 PID:ND S-5(8 to 10'):Medium dense,brown,fine to coarse 6 �•'� SAND,some Gravel,trace Silt.Wet. 13 13 �! 0 10— •� — Q +r. w *' SAND& x w z .r GRAVEL 0 12— — m z •�! a U) - i N 1.1. 14— �• — 0 �. w S-6 15-17 1 24/8 PID:ND S-6(15 to IT):Loose,light brown,fine to coarse = 2 1 �. SAND,some Gravel,trace Silt.Wet. K 16— 4 o' — m 6 •'�i r. i S, Itr - 17'----- Boring terminated at 17 feet.No refusal N encountered. 18— — $ NOTES: - 1.Soil Samples were screened for volatile organic - compounds(VOCs)using a Tiger Photoionization 0 Detector(PID)with a 10.6 eV lamp,calibrated to a 20— 100 parts per million by volume(ppmv) — isobutylene-in air standard using a response factor O of 1.0.Results are presented in ppmv;the typical 3 - detection limit is 1 ppmv.ND indicates not detected. - o NA indicates not available.the PID measures N relative levels of VOCs.Although PID screening v 22— cannot be used to directly quantify VOC — 0 concentrations or identify individual compounds,the m results can serve as a relative indicator for the - presence of VOCs. a - c� O 24— — z 0 O in - - Sheet:1 of 1 Project:Berkley Investments Log of Boring SH-103 SA N B OR N 1111 HEAD Location:Watertown,MA Ground Elevation:12±feet Project No.:4928.00 Datum:NAVD88 Sanborn,Head&Associates,Inc. Drilling Method:Truck Mounted B57 Mobil Rig,4.25"O.D.Hollow Stem Augers Sampling Method:2"O.D.Split Spoon,Automatic Hammer Groundwater Readings Depth Depth Depth Stab. Date Time to Water Ref.Pt. of Casing of Hole Time Drilling Company:Crawford Drilling Services,LLC 01/18/21 13:45 7.5' Ground Surface 6' 8' 20 Minutes Foreman:J.Martinelli Date Started:01/18/21 Date Finished:01/18/21 Logged By:J.Sousa Checked By:Q.Pratt Sample Information Stratum Depth Spoon Pen/ Field Geologic Description Remarks (ft) Sample Depth Blows Rec Testing Log Description g P No. (ft) oer 6 in (in) Data 0 ; ASP ALT (0 to 05):ASPHALT. S-1 0.5-2 13 18/12 PID:ND -0.5 S-1(0.5 to 2'):Dense,brown/black,fine to coarse - 24 SAND,some Gravel,trace Silt,trace Ash particles, - 23 I very few Brick particles.Moist.FILL. 2 S-2 2-4 34 24/12 PID:ND V- S-2(2 to 4'):Dense,brown,fine to coarse SAND, 22 I some Gravel,trace Silt,few Brick pieces,few Ash 11 particles.Moist.FILL. _ 10 I S-3 4-6 10 24/0 I FILL S-3(4 to 6'):Medium dense,No recovery.FILL. 7 5 6 _ I 6 S-4 6-8 10 24114 PID:ND I S-4(6 to 8'):Dense,brown/light brown,fine to 18 coarse SAND and Gravel,trace Silt.Moist to Wet. 17 FILL. _ 9 I 8 S-5 8-10 62 24/6 PID:ND 8 S-5(8 to 10'):Very dense,brown,fine to coarse 54 �,R. SAND and GRAVEL,trace Silt.Wet. 42 .•.,4 41 F • � •R QQ W •.,• 2 z 0 12— •�� — z SAND& GRAVEL U) _ •: _ m 14— i — 0 " R w S-6 15-17 5 24/3 PID:ND !'!, S-6(15 to 17'):Medium dense,brown,fine to coarse z 5 ;•: SAND and GRAVEL,some Silt.Wet. 9 0 16— 9 m z :'•�. < -----17------ Boring terminated at 17 feet.No refusal N encountered. 18— — $ NOTES: - 1.Soil Samples were screened for volatile organic - compounds(VOCs)using a Tiger Photoionization 0 Detector(PID)with a 10.6 eV lamp,calibrated to a 20— 100 parts per million by volume(ppmv) — isobutylene-in air standard using a response factor 0 of 1.0.Results are presented in ppmv;the typical 3 - detection limit is 1 ppmv.ND indicates not detected. - o NA indicates not available.the PID measures N relative levels of VOCs.Although PID screening v 22— cannot be used to directly quantify VOC — 0 concentrations or identify individual compounds,the 0 m results can serve as a relative indicator for the - presence of VOCs. a - 0 O 24— — z E O in - - Sheet:1 of 1 Project:Berkley Investments Log of Boring SH-104 SA N B OR N 1111 HEAD Location:Watertown,MA Ground Elevation:10±feet Project No.:4928.00 Datum:NAVD88 Sanborn,Head&Associates,Inc. Drilling Method:Truck Mounted B57 Mobil Rig,4.25"O.D.Hollow Stem Augers Sampling Method:2"O.D.Split Spoon,Automatic Hammer Groundwater Readings Depth Depth Depth Stab. Date Time to Water Ref.Pt. of Casing of Hole Time Drilling Company:Crawford Drilling Services,LLC 01/18/21 14:50 5.4' Ground Surface 4' 6' 20 Minutes Foreman:J.Martinelli Date Started:01/18/21 Date Finished:01/18/21 Logged By:J.Sousa Checked By:Q.Pratt Sample Information Stratum Depth Spoon Pen/ Field Geologic Description Remarks (ft) Sample Depth Blows Rec Testing Log Description g p No. (ft) oer 6 in (in) Data 0 ; ASP ALT (0 to 05):ASPHALT. S-1 0.5-2 6 18/5 PID:ND -0.5 S-1(0.5 to 2'):Medium dense,light brown/brown, - 7 fine to coarse SAND,some Gravel,trace Silt,very - 5 I few Brick pieces.Moist.FILL. 5 2 S-2 2-4 10 24/14 PID:ND V- S-2(2 to 4'):Medium dense,light brown/brown,fine 7 I to coarse SAND,some Gravel,trace Silt,very few 14 Brick pieces.Moist.FILL. _ 8 I S-3 4-6 3 24/7 PID:ND I FILL S-3(4 to 6'):Loose,brown,fine to coarse SAND, 3 some Gravel,trace Silt,few Brick fragments.Moist to 4 i, Wet.FILL. 4 _ I 6 S-4 6-8 10 24110 PID:ND I S-4(6 to 8'):Dense,brown,fine to coarse SAND, 20 some Gravel,some Silt.Wet.FILL. 29 _ 20 I 8 S-5 8-10 15 24/6 PID:ND 8 S-5(8 to 10'):Dense,brown/gray,fine to coarse 20 �,R. SAND and GRAVEL,some Silt.Wet. N _ 21 �.•� - �_ 18 F • � •R QQ W •.,• 2 z 0 12— •�� — z SAND& GRAVEL U) _ •: _ m 14— i — 0 " R w S-6 15-17 34 24114 PID:ND !'!, S-6(15 to IT):Medium dense,brown/gray,fine to z 18 ;•. coarse SAND,some Gravel,trace Silt.Wet. 8 0 16— 7 m z :'•�. < -----17------ Boring terminated at 17 feet.No refusal N encountered. 18— — $ NOTES: - 1.Soil Samples were screened for volatile organic - compounds(VOCs)using a Tiger Photoionization 0 Detector(PID)with a 10.6 eV lamp,calibrated to a 20— 100 parts per million by volume(ppmv) — isobutylene-in air standard using a response factor 0 of 1.0.Results are presented in ppmv;the typical 3 - detection limit is 1 ppmv.ND indicates not detected. - o NA indicates not available.the PID measures N relative levels of VOCs.Although PID screening v 22— cannot be used to directly quantify VOC — 0 concentrations or identify individual compounds,the 0 m results can serve as a relative indicator for the - presence of VOCs. a - 0 O 24— — z E O in - - Sheet:1 of 1 TEST BORING LOG (page 1 of 7) Project 2017-03-0159 Boring ID: INC. 64 Pleasant St. IES-1 ENVIRONMENTAL CONSULTANTS Watertown, MA Date Started: 3/31/17 Geologist: John Beck Drilling Contractor: Date Finished: 3/31/17 Project Manager: Steve Iorio TDS Depth Casing Sample Visual Identification of (feet) bl/ft No. OVM Depth Blows/6" Strata Soil and/or Rock Sample Asphalt 1 S-1 0 0'-5101, (rec.2')Dry,dk gy,mixed sd,gravel,rock and brick fill. 5 S-2 Trace 5'0"-10'0" 13' (rec.2')Damp,gy,sd and gravel fill w/brick over (0.1) 1.5'of wet,dk gy coarse gravel and coarse sd. Faint oil odor. 10 S-3 0 10'0"-13'0" (rec.3')Wet,gy,well sorted,coarse sand.Refusal at 13'in what appears to be concrete. End of probe at 13' 0"due to refusal 15 Groundwater encountered at approx. 5'6". Monitoring well set at 13'. 20 25 30 Rig: Track-mounted,percussion hammer driving system(geoprobe) Sampling Equipment: 11/8"diameter stainless-steel sampling tube. OVM=Organic Vapor Meter(parts per million-calibrated to benzene standard). Cohesionless: 0-4 =Very Loose;4-10=Loose; Trace: 0%— 10% 10-30=Medium Dense;30-50=Dense;50+=Very Dense Little: 10%—20% Cohesive: 0-2=Very Soft;2-4=Soft;4-8=Medium Stiff; Some: 20%—35% 8-15=Stiff; 15-30=Very Stiff;30+=Hard And: 35%—50% TEST BORING LOG (page 2 of 7) ❑ Project 2017-03-0159 Boring ID: 64 Pleasant St. IES-2 ENVIRONMENTAL CONSULTANTS Watertown, MA Date Started: 3/31/17 Geologist: John Beck Drilling Contractor: Date Finished: 3/31/17 Project Manager: Steve Iorio TDS Depth Casing Sample Visual Identification of (feet) bl/ft No. Pen/Rec Depth Blows/6" Strata Soil and/or Rock Sample Asphalt 1 S-1 0 0'0"-5'0" (rec.2')Dry,dk gy to dk brn,coarse sandy fill containing fragments of asphalt or coal,brick,and rusty metal. 5 S-2 0 5'0"-10'0" (rec. 1')Wet,brn,coarse sd with pebbles. 15' 10 S-3 0 10'0"- 15'0" (rec. 1.5')Wet,bm,coarse sd and fine gravel. 15 End of probe at 15' 0" Groundwater encountered at approx. 5'6". Monitoring well set at 13'. 20 25 30 35 Rig: Track-mounted,percussion hammer driving system(geoprobe) Sampling Equipment: 13/8"diameter stainless-steel sampling tube. OVM=Organic Vapor Meter(parts per million-calibrated to benzene standard). Cohesionless: 0-4 =Very Loose;4-10=Loose; Trace: 0%— 10% 10-30=Medium Dense;30-50=Dense;50+=Very Dense Little: 10%—20% Cohesive: 0-2=Very Soft;2-4=Soft;4-8=Medium Stiff; Some: 20%—35% 8-15=Stiff, 15-30=Very Stiff,30+=Hard And: 35%—50% TEST BORING LOG (page 3 of 7) Project 2017-03-0159 Boring ID: ;L�. MC. 64 Pleasant St. IES-3 ENVIRONMENTAL CONSULTANTS Watertown, MA Date Started: 3/31/17 Geologist: John Beck Drilling Contractor: Date Finished: 3/31/17 Project Manager: Steve Iorio TDS Depth Casing Sample Visual Identification of (feet) bl/ft No. Pen/Rec Depth Blows/6" Strata Soil and/or Rock Sample Asphalt 1 S-1 0 0'0"-5'0" (rec.2.5')Dry,gy sandy fill mixed with fragments of concrete,rock,pebbles and occ.brick. 5 S-2 0 5'0"-10'0" 15' (rec.3') 1'of dry,broken,white concrete and pebbles over 2'of wet,brn,vy coarse gravel and sd. 10 S-3 0 10'0"-12'6" (rec.2')Wet,gy,gravel and sd. S-4 0 12'6"- 15'0" (rec.2')Wet,gy to brn,poorly sorted,coarse sd and gravel w/occ.rocks. 15 End of probe at 15' 0". Groundwater encountered at approx. 7'6". Monitoring well set at 13'. 20 25 30 Rig: Track-mounted,percussion hammer driving system(geoprobe) Sampling Equipment: 13/8"diameter stainless-steel sampling tube. OVM=Organic Vapor Meter(parts per million-calibrated to benzene standard). Cohesionless: 0-4 =Very Loose;4-10=Loose; Trace: 0%— 10% 10-30=Medium Dense;30-50=Dense;50+=Very Dense Little: 10%—20% Cohesive: 0-2=Very Soft;2-4=Soft;4-8=Medium Stiff, Some: 20%—35% 8-15=Stiff, 15-30=Very Stiff,30+=Hard And: 35%—50% TEST BORING LOG (page 4 of 7) Project 2017-03-0159 Boring ID: INC. 64 Pleasant St. IES-4 ENVIRONMENTAL CONSULTANTS Watertown, MA Date Started: 3/31/17 Geologist: John Beck Drilling Contractor: Date Finished: 3/31/17 Project Manager: Steve Iorio TDS Depth Casing Sample Visual Identification of (feet) bl/ft No. Pen/Rec Depth Blows/6" Strata Soil and/or Rock Sample Asphalt 1 S-1 0 010"-5'0" (rec.2.5')Dry,mixed,dk brn,sandy fill containing a 5"layer of concrete,over 1'of dk bm,coarse sd w/wood and rusty metal fragments. 5 S-2 0 5'0"-7'6" 15' (rec.4') 1'of wet,dk brn,gravelly fill w/bricks, over 1.5'of dry,brn sd w/rock(sample S-2),over S-3 24 7'6"-10'0" 1.5'of wet,mixed,greenish-gray,coarse sd and gravel w/gasoline odor(sample S-3). 10 S-4 4 10'0"-15'0" (rec.4')Wet,poorly sorted,brn,coarse sd& gravel w/pebbles and slight gasoline odor. 15 End of probe at 15' 0". Groundwater encountered at approx. 7'6". Monitoring well set at 13'. 20 25 30 35 Rig: Track-mounted,percussion hammer driving system(geoprobe) Sampling Equipment: 11/8"diameter stainless-steel sampling tube. OVM=Organic Vapor Meter(parts per million-calibrated to benzene standard). Cohesionless: 0-4 =Very Loose;4-10=Loose; Trace: 0%— 10% 10-30=Medium Dense;30-50=Dense;50+=Very Dense Little: 10%—20% Cohesive: 0-2=Very Soft;2-4=Soft;4-8=Medium Stiff, Some: 20%—35% 8-15=Stiff, 15-30=Very Stiff,30+=Hard And: 35%—50% TEST BORING LOG (page 5 of 7) Project 2017-03-0159 Boring ID: INC. 64 Pleasant St. B-5 ENVIRONMENTAL CONSULTANTS Watertown, MA Date Started: 3/31/17 Geologist: John Beck Drilling Contractor: Date Finished: 3/31/17 Project Manager: Steve Iorio TDS Depth Casing Sample Visual Identification of (feet) bl/ft No. Pen/Rec Depth Blows/6" Strata Soil and/or Rock Sample Asphalt 1 S-1 0 010"-5'0" (rec.2')Dry,mixed,bm to light bm,sd,gravel and concrete fill. 10' 5 S-2 0 5'0"-10'0" (rec.3.5') 1'of dry,sandy fill over 2.5'of wet,gy to bm,poorly sorted,sd and gravel w/occ. pebbles. 10 End of probe at 10' 0". Groundwater encountered at approx. 7'6". No monitoring well set. 15 20 25 30 Rig: Track-mounted,percussion hammer driving system(geoprobe) Sampling Equipment: 11/8"diameter stainless-steel sampling tube. OVM=Organic Vapor Meter(parts per million-calibrated to benzene standard). Cohesionless: 0-4 =Very Loose;4-10=Loose; Trace: 0%— 10% 10-30=Medium Dense;30-50=Dense;50+=Very Dense Little: 10%—20% Cohesive: 0-2=Very Soft;2-4=Soft;4-8=Medium Stiff, Some: 20%—35% 8-15=Stiff, 15-30=Very Stiff,30+=Hard And: 35%—50% TEST BORING LOG (page 6 of 7) Project 2017-03-0159 Boring ID: INC. 64 Pleasant St. B-6 ENVIRONMENTAL CONSULTANTS Watertown, MA Date Started: 3/31/17 Geologist: John Beck Drilling Contractor: Date Finished: 3/31/17 Project Manager: Steve Iorio TDS Depth Casing Sample Visual Identification of (feet) bl/ft No. Pen/Rec Depth Blows/6" Strata Soil and/or Rock Sample Asphalt 1 S-1 0 010"-5'0" (rec.3')Dry,mixed,gy,white and black,sandy fill containing coal or asphalt and construction debris. 5 S-2 0 5'0" 10'0" 15' (rec.2'8")2'of wet,mixed,gy,brn and white sandy fill w/construction debris,over 8"of wet, gy to light brn,coarse sd w/occ.pebbles. 10 S-3 0 10'0"-15'0" (rec.5')Wet,brn to rusty brn,coarse sd w/ pebbles at the top. 15 End of probe at 15' 0". Groundwater encountered at approx. 6'. No monitoring well set. 20 25 30 Rig: Track-mounted,percussion hammer driving system(geoprobe) Sampling Equipment: 13/8"diameter stainless-steel sampling tube. OVM=Organic Vapor Meter(parts per million-calibrated to benzene standard). Cohesionless: 0-4 =Very Loose;4-10=Loose; Trace: 0%— 10% 10-30=Medium Dense;30-50=Dense;50+=Very Dense Little: 10%—20% Cohesive: 0-2=Very Soft;2-4=Soft;4-8=Medium Stiff; Some: 20%—35% 8-15=Stiff; 15-30=Very Stiff;30+=Hard And: 35%—50% TEST BORING LOG (page 7 of 7) Project 2017-03-0159 Boring ID: INC. 64 Pleasant St. B-7 ENVIRONMENTAL CONSULTANTS Watertown, MA Date Started: 3/31/17 Geologist: John Beck Drilling Contractor: Date Finished: 3/31/17 Project Manager: Steve Iorio TDS Depth Casing Sample Visual Identification of (feet) bl/ft No. Pen/Rec Depth Blows/6" Strata Soil and/or Rock Sample Asphalt 1 S-1 0 010"-5'0" (rec.2.5')Dry,mixed,gy,brn and black sandy fill with brick and concrete fragments. 5 S-2 0 5'0"-10'0" (rec.2.5')Damp to wet,mixed sandy fill 15' containing construction material and brick,over 1' of wet,brn to dk brn gravel. 10 S-3 0 10'0"-15'0" (rec.3')Wet,brn,coarse gravel and broken rocks. End of probe at 15' 0". Groundwater encountered at approx. 6'to 7'. 15 No monitoring well set. 20 25 30 Rig: Track-mounted,percussion hammer driving system(geoprobe) Sampling Equipment: 11/8"diameter stainless-steel sampling tube. OVM=Organic Vapor Meter(parts per million-calibrated to benzene standard). Cohesionless: 0-4 =Very Loose;4-10=Loose; Trace: 0%— 10% 10-30=Medium Dense;30-50=Dense;50+=Very Dense Little: 10%—20% Cohesive: 0-2=Very Soft;2-4=Soft;4-8=Medium Stiff; Some: 20%—35% 8-15=Stiff; 15-30=Very Stiff;30+=Hard And: 35%—50% APPENDIX D: EXISTING CONDITIONS HYDROLOGIC ANALYSIS ➢ EXISTING CONDITIONS DRAINAGE MAP ➢ EXISTING CONDITIONS HYDROCAD COMPUTATIONS PLE ,� � N / COW.%7E SMOMM [ A S lV T (PUBLIC V WlD a AM - AR/ABLE TH W II� E � ' STREET � r^� raa 17Ar N8650�20 Ems` _ 44) 1 r Mr<,a I<♦o �� z.,ssl ��� � rx� (_ n Abia ,orlA, 5AIDN(RD) G2�-J il.rsn + 2 W y W C _ > r. rbNCRE,E sAOET,'AT/! w 2 a¢z Q I �raw A.raw Vr O p n z�IY a --- •` I >, •+Tl— N78'705D'`{' _ � cfz�aF-o HE • R=1 14s.34' CTAYCHF7F � W�y a /,,• ,4M I .MIAIL ..- _ _rs_ AA}S �' ' AAA' > a ~ k A'r ,wNLv Isar<-u,p c^ YP 1 a @ y"EEr.CY1NG --- ------------ — laAlr \ \ BPoL'K PAlap PATKJ \\ ,aa 0 Ian Cft \ MD M 17f + _ � w� •q�, OCOM 4,e REVISNS ONWEq� _ Q MASSACHSU REV DATE .MMEHTEX DETENTION s4sW DEL BON Aft ARFA USED FM PAW, i////////////////// 1 ,� err.Dq — 1� PERFORMED BY EPSILON — + \ /+Ij ASSOCATES IN OCTOBER OF � 2016. /I / \ I 1-SAY 'Al.•s� / ,tw '.Y PAWR lATAD / Q in ry xi, \// 01) IRA ru _ \ /r-rru �, r r'a♦ 4 FIB \ AI0 I 900(r.X RID- ///n////// q Y 15D'VE7Lft � 16xn'¢+'nG '1► a'�, 1 � ,e- u/ '++ / \ \ II 2-STORY eRMX --below. Call befom You dig. -�7n4- rA I1 _ MINIUM UNIT � ALWAYS CALL811 ^� It's fast.It's free.It's the law. ,tik d\1 'two&*R, II //•/ FOR CONCEPT ool 1,.9 wJ �y' 1 /////////\/✓//// _RD nA,o XK t�F �,HR c / �� / / PURPOSES ONLY � ///A//////// Ay vENT 2nd M To /Ws RID _---.ip Al OPFCO o«� s�.ow.,Eoam..„s, \ ATOC ALy,Egs 2-STOA•yI / 121 ® / _ _>F_ ♦E �1D• '� \\ qe B ]7579,PAZ48 P D ROJECTNo� s`M201051 BY: WND/ACL RAWN \ u Y ♦ IY as \\\ M&S J \\ / � CHECKED BY: ZLR CAD I.D. M201051CVL-0 1 AXJC 4a / NOW O//. ° / a DATE: 05I0&2021 5�r DETAq \ CONDOM/N/�/M wss pp/7 aao CM-2 CO/N���QI a» ----- ° 11� \\ "j I p 4 ' A•I UNIT 2 RI ,I�.i IID .\\ _ \\ '� /` \ PROJECT' LOT 3 N \_ aw N/ 11C417152t ��� <» \ AYlI ^ PROPOSED SITE D P 1 PLAN DOCUMENTS 1 FOR Ayy , �, BERKELEY P v-fo3 INVESTMENTS, a-,zs -104 \ an 1. / ° INC. �8-123 PROPOSED DEVELOPMENT 64 PLEASANT STREET �1.C011C ` < aAlr \ TOWN ESEXCATERTOWN COUNTY, WETUND DELINEATION PERFORMED `�\\ �- \ _ _ /� BY EPSILON ASSOCIATES/N B_f� V \ ///} MIDDLESEX COUNTY, OCTOBER OF 2016. //`\\ �.J \\` \M \" \ a — / CROSSRA,{� L MASSACHUSETTS 84NK DELINEATION PERFORATED J \\\•\\\\-\ ` 4�,� \ \ a+1 CERr 247051 BY EPSILON W20 5 \ e-+zo ��,�� ''\� \ "` tg,r O ,aa— f, / _ [CC 17152D ,' i � � as ,� �. [DTI BOHLER// mas "a 45 FRANKLIN STREET,Sth FLOOR / wE"AND \\ \\� \ \ Ly. 0¢'' ,•\4' � BOSTON,MA02110 �' (617)849-8040 rr www.BohlerEngineering.com \ �. \� �.!O%�11' O.�A.�, ate,ts'\\ � �\ `>ys / \ \ NDO M UNIT 2 TeM-2 "19N"Y! \ s c 'YUI�O.r + Now Or otrneniv F CROSSRAM UC LCC r \� �w a[ �• ND L01520 o`\\\y\ er 44A. DOC 119e,o,\ SHEET TITLE: a yti a w \\a EXISTING 3, 'y' azr \\\ 'mac. `\ CONDITIONS \ <. WATERSHED \ 1 O as w \\ \ MAP \ \ SHEET NUMBER: �Wo WS-EX ORG 1 .DATE-0510fi/2021 n ' I M2O1051_Pre_Rev-1 Prepared by Bohler Engineering Printed 5/4/2021 HVdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 2 Area Listing(all nodes) Area CN Description (acres) (subcatchment-numbers) 0.219 61 >75%Grass cover,Good,HSG B (EX-1,EX-2) 1.231 98 Paved parking,HSG B (EX-1,EX-2) 0.767 98 Roofs,HSG B (EX-1a,EX-2a) 2.217 94 TOTAL AREA EX-1 EX-1a EX_2 EX-2a Subcatchmen EX-1 Bldg Area SubcatchmelEX-2 LY Bldg Area P-1 P-2 CCCSSSS Ex.Surface Pdi Su on rface Ponding DP-1 Subcat Reach on Link I Routing Diagram for M201051_Pre_Rev-1 Prepared by Bohler Engineering, Printed 5/4/2021 HydroCAD®10.00-19 s/n 08955 0 2016 HydroCAD Software Solutions LLC M201051_Pre_Rev-1 M201051_Pre_Rev-1 Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD®10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 3 HvdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 4 Soil Listing(all nodes) Ground Covers(all nodes) Area Soil Subcatchment HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment (acres) Group Numbers (acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers 0.000 HSG A 0.000 0.219 0.000 0.000 0.000 0.219 >75%Grass cover,Good EX-1, 2.217 HSG B EX-1,EX-1a,EX-2,EX-2a EX-2 0.000 HSG C 0.000 1.231 0.000 0.000 0.000 1.231 Paved parking EX-1, 0.000 HSG D EX-2 0.000 Other 0.000 0.767 0.000 0.000 0.000 0.767 Roofs EX-1a, 2.217 TOTAL AREA EX-2a 0.000 2.217 0.000 0.000 0.000 2.217 TOTAL AREA M201051_Pre_Rev-1 M201051_Pre_Rev-1 Type/I/24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD®10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 5 HvdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 6 Pipe Listing(all nodes) Time span=0.00-30.00 hrs,dt=0.02 hrs,1501 points Runoff by SCS TR-20 method,UH=SCS,Weighted-CN Line# Node In-Invert Out-Invert Length Slope n Diam/Width Height Inside-Fill Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Number (feet) (feet) (feet) (ft/ft) (inches) (inches) (inches) SubcatchmentEX-1:SubcatchmentEX-1 Runoff Area=29,830 sf 80.82%Impervious Runoff Depth=2.26" 1 EP-1 4.00 3.90 23.0 0.0043 0.011 15.0 0.0 0.0 Tc=6.0 min CN=91 Runoff=1.78 cfs 0.129 of 2 EP-2 4.00 3.90 10.0 0.0100 0.011 15.0 0.0 0.0 SubcatchmentEX-1a:Ex Bldg Area Runoff Area=13,459 sf 100.00%Impervious Runoff Depth=2.97" Tc=6.0 min CN=98 Runoff=0.96 cfs 0.076 of SubcatchmentEX-2:SubcatchmentEX-2 Runoff Area=33,326 sf 88.50%Impervious Runoff Depth=2.54" Tc=6.0 min CN=94 Runoff=2.18 cfs 0.162 of SubcatchmentEX-2a:Ex Bldg Area Runoff Area=19,957 sf 100.00%Impervious Runoff Depth=2.97" Tc=6.0 min CN=98 Runoff=1.42 cfs 0.113 of Pond EP-1:Ex.Surface Ponding Peak EIev=5.01' Storage=13 cf Inflow=2.74 cfs 0.205 of 15.0" Round Culvert n=0.011 L=23.0' S=0.0043'/' Outflow=2.74 cfs 0.205 of Pond EP-2:Ex Surface Ponding Peak EIev=5.17' Storage=15 cf Inflow=3.60 cfs 0.275 of 15.0" Round Culvert n=0.011 L=10.0' S=0.0100'/' Oufflow=3.60 cfs 0.275 of Link DP-1: Inflow=6.34 cfs 0.481 of Primary=6.34 cfs 0.481 of Total Runoff Area=2.217 ac Runoff Volume=0.481 of Average Runoff Depth=2.60" 9.89%Pervious=0.219 ac 90.11%Impervious=1.998 ac M201051_Pre_Rev-1 Type 111 24-hr 2-YR Rainfall=3.20" M201051_Pre_Rev-1 Type 111 24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 7 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 8 Summary for Subcatchment EX-1:Subcatchment EX-1 Summary for Subcatchment EX-1 a:Ex Bldg Area Runoff = 1.78 cfs @ 12.09 hrs, Volume= 0.129 af, Depth= 2.26" Runoff = 0.96 cfs @ 12.08 hrs, Volume= 0.076 af, Depth= 2.97" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 2-YR Rainfall=3.20" Type III 24-hr 2-YR Rainfall=3.20" Area(sf) CN Description Area(sf) CN Description 5,720 61 >75%Grass cover,Good,HSG B 13,459 98 Roofs,HSG B 24,110 98 Paved parkinq,HSG B 13,459 100.00%Impervious Area 29,830 91 Weighted Average 5,720 19.18%Pervious Area Tc Length Slope Velocity Capacity Description 24,110 80.82%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment EX-1 a: Ex Bldg Area 6.0 Direct Entry,Ab Hydrograph Subcatchment EX-1:Subcatchment EX-1 i l l l I I I I I — — ❑Runoff Hydrograph t/ Deems I I II I Type III 247hr em ■R�noff I I ?-YR IRginf4117-1?0" I I I I I Type,III 441hr I I I I I I I I I I I I I I I RIu IngfflAyrgar-113,14591 Sf I I I I I ?-XR IRaiinfalll:=1-4'i I I I I I I I I I I I I I IRunofflVolluMe:90.07I IRlumgfflAyrgar-A9,18301s _ I I I I I Runoff Depth7-2.97" IRungfflVpllumq�0.11291af LL I I I I I I I I I I I I ITc=6L0 min I fi -Runoff DepthF2.26�'- I I I I I I Tc�6L01 min I I I I I I II I I I I I I I I I I I I I I I I I I I I I I 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 / -/ /.../ .... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type 111 24-hr 2-YR Rainfall=3.20" M201051_Pre_Rev-1 Type 111 24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 9 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 10 Summary for Subcatchment EX-2:Subcatchment EX-2 Summary for Subcatchment EX-2a: Ex Bldg Area Runoff = 2.18 cfs @ 12.08 hrs, Volume= 0.162 af, Depth= 2.54" Runoff = 1.42 cfs @ 12.08 hrs, Volume= 0.113 af, Depth= 2.97" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 2-YR Rainfall=3.20" Type III 24-hr 2-YR Rainfall=3.20" Area(sf) CN Description Area(sf) CN Description 3,834 61 >75%Grass cover,Good,HSG B 19,957 98 Roofs,HSG B 29,492 98 Paved parkinq,HSG B 19,957 100.00%Impervious Area 33,326 94 Weighted Average 3,834 11.50%Pervious Area Tc Length Slope Velocity Capacity Description 29,492 88.50%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment EX-2a: Ex Bldg Area 6.0 Direct Entry, Hydrograph Subcatchment EX-2:Subcatchment EX-2 i l l l I I I I I I I I I I ,Q�bs ( I I I I I I I I I I I I I ■Runoff Hydrograph lll Type, 7 111 24 hr illlllllllllllllll I III II II II IIIIII Illllll z.,a •Rug ?-YR Rginfa117-81-W, I +I+ + 1 1 -f + ITypeI111�47hr I I I I I_I IRIu ingfflAyrgar-119,0$71St 2� I I I I I I I I I I I I I I I I ?-YR Relinf-111�1-47 I I I I 11 1 IRunofflVollumeg0.11131af I I I I I I I I I I I I I IRlumgffiArgaF-j3,13?61Sf I I I I I I I I I I Runoff Depthr-2.977 IRUngfflVp1lume:90.l1621af I I I I I I I I I ITc*6L0 min I I I I I I I I I I I I Runoff Depthr-2.541' 1 1 1 CN=98 0 I—I I--1 + +I—I + I—I -i + I—I TC::&Ot fnin— I I I I I I I I I I I I I ' IIIIIIIIII IIII II II IIII �N=94 III I IIIIII I I o IIIIIIIIII IIII II II II II II II I I I I IIIIII I I IIIIIIIII III II II II II II II 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) o 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type 111 24-hr 2-YR Rainfall=3.20" M201051_Pre_Rev-1 Type 111 24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 11 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 12 Summary for Pond EP-1: Ex.Surface Ponding Pond EP-1: Ex.Surface Ponding Hydrograph Inflow Area= 0.994 ac, 86.79%Impervious, Inflow Depth= 2.48" for 2-YR event I+ +I_ 1-1 + 1-1 +I+ I---I 1-1 + -1 + 1-4 1- Inflow = 2.74 cfs @ 12.09 hrs, Volume= 0.205 of ■innew Outflow, = 2.74 cfs @ 12.09 hrs, Volume= 0.205 af, Atten=0%, Lag=0.0 min 3-� 1 1 1 1 1 1 1 1 10 Primary Primary = 2.74 cfs @ 12.09 hrs, Volume= 0.205 of I I I I I 1 1 2,11 1 1 �f�flpylr�► ep7q.g94 pq Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs I I I I I I I I I I I I I IPoakl IIII.Q11 Peak Elev=5.01'@ 12.09 hrs Surf.Area=13 sf Storage=13 cf r-1-i r 1-1 -r 1 ItOlrag1e:F1137cf- Plug-Flow detention time=0.3 min calculated for 0.205 of(100%of inflow) 2- 1 1 1 1 1 1 1 1 1 1 1 1 1 115.0111 Center-of-Mass det.time=0.3 min(785.6-785.3) 1 1 1 1 1 1 1 k6ulnd CUIV6rt Volume Invert Avail.Storage Storaqe Description o 6J0.01 f #1 10.70' 6,946 cf Custom Stage Data(Prismatic)Listed below(Recalc) LL L ✓ #2 4.00' 94 cf 4.00'D x 7.50'H Ex.DMH L-23.0 7,040 cf Total Available Storage �=0f06431 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 10.70 4 0 0 11.00 627 95 95 0 12.00 13,076 6,852 6,946 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours( Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=23.0' RCP,sq.cut end projecting, Ke=0.500 Inlet/Outlet Invert=4.00'/3.90' S=0.0043'P Cc=0.900 n=0.011 Concrete pipe,straight&clean, Flow Area=1.23 sf Primary OutFlow Max=2.72 cfs @ 12.09 hrs HW=5.01' (Free Discharge) t1=Culvert(Barrel Controls 2.72 cfs @ 3.51 fps) M201051_Pre_Rev-1 Type Ill 24-hr 2-YR Rainfall=3.20" M201051_Pre_Rev-1 Type 111 24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 13 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 14 Summary for Pond EP-2:Ex Surface Ponding Pond EP-2: Ex Surface Ponding Inflow Area= 1.223 ac, 92.80%Impervious, Inflow Depth= 2.70" for 2-YR event Hydrograph i Irt 1 I� TI-I T -Irt rlrt 1 I_1 T -I T -Irt Irt 1 Inflow = 3.60 cfs @ 12.08 hrs, Volume= 0.275 of ■Mr.. Outflow, = 3.60 cfs @ 12.09 hrs, Volume= 0.275 af, Atten=0%, Lag=0.0 min 4- 1 1 1 1 1 1 1 1 10 Pnmery Primary = 3.60 cfs @ 12.09 hrs, Volume= 0.275 of I I I I I I I I �► ep7l,.?2�pq Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs T 1 1 T T 1 T F I-i T IFIVOI-WOVF:5 7r Peak Elev=5.17'@ 12.09 hrs Surf.Area=13 sf Storage=15 cf 3 1 1 1 1 1 1 1 1 IStolrage:l:15 id Plug-Flow detention time=0.2 min calculated for 0.275 of(100%of inflow) I I I I I I I I I I I 1 1 115.017 Center-of-Mass det.time=0.2 min(774.7-774.5) I I I I I R6Unt11C1_14/6rt Volume Invert Avail.Storage Storaqe Description o 2 1 1 1 1 1 1 1 1 1 1 _� #1 4.00' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder I I I I I I I I I I L JJ 1 ✓I #2 7.50' 4,935 cf Custom Stage Data(Irregular)Listed below(Recalc) - -7 Q0- 4,979 cf Total Available Storage 1 1 1 1 1 �=0f01401 �1 Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 7.50 4 8.0 0 0 4 8.00 556 93.0 101 101 688 o 9.00 11,424 471.0 4,833 4,935 17,655 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=10.0' RCP,sq.cut end projecting, Ke=0.500 Inlet/Outlet Invert=4.00'/3.90' S=0.0100'P Cc=0.900 n=0.011 Concrete pipe,straight&clean, Flow Area=1.23 sf Primary OutFlow Max=3.58 cfs @ 12.09 hrs HW=5.16' (Free Discharge) t1=Culvert(Barrel Controls 3.58 cfs @ 3.92 fps) M201051_Pre_Rev-1 Type 11124-hr 2-YR Rainfall=3.20" M201051_Pre_Rev-1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 15 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 16 Summary for Link DP-1: Time span=0.00-30.00 hrs,dt=0.02 hrs,1501 points Runoff by SCS TR-20 method,UH=SCS,Weighted-CN Inflow Area= 2.217 ac, 90.11%Impervious, Inflow Depth= 2.60" for 2-YR event Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Inflow = 6.34 cfs @ 12.09 hrs, Volume= 0.481 of Primary = 6.34 cfs @ 12.09 hrs, Volume= 0.481 af, Atten=0%, Lag=0.0 min SubcatchmentEX-1:SubcatchmentEX-1 Runoff Area=29,830 sf 80.82%Impervious Runoff Depth=3.89" Tc=6.0 min CN=91 Runoff=2.99 cfs 0.222 of Primary outflow=Inflow,Time Span=0.00-30.00 hrs,dt=0.02 hrs SubcatchmentEX-1a:Ex Bldg Area Runoff Area=13,459 sf 100.00%Impervious Runoff Depth=4.66" Link DP-1: Tc=6.0 min CN=98 Runoff=1.48 cfs 0.120 of Hydrograph SubcatchmentEX-2:SubcatchmentEX-2 Runoff Area=33,326 sf 88.50%Impervious Runoff Depth=4.21" -t t-11 fi 1-1 t I I -t I 1 t-11 fi 1-1 t -I -t Tc=6.0 min CN=94 Runoff=3.51 cfs 0.268 of �� ❑Inflow 7 e ��. : i °Primary SubcatchmentEX-2a:Ex Bldg Area Runoff Area=19,957 sf 100.00%Impervious Runoff Depth=4.66" �fpW IArqa-F-I� -7 1- Tc=6.0 min CN=98 Runoff=2.19 cfs 0.178 of s-� _I J L I J -L J L I I -i L I J L 1_I 1 I_1 1 L I J L Pond EP-1:Ex.Surface Ponding Peak Elev=5.41' Storage=18 cf Inflow=4.46 cfs 0.342 of 5% I I I I I I I I I I I I I I I I I I I I I I I 1 1 15.0" Round Culvert n=0.011 L=23.0' S=0.0043'/' Outflow=4.46 cfs 0.342 of -I t t 11 t - t 1 1 t 1-1 t -1 t I 1 t Pond EP-2:Ex Surface Ponding Peak Elev=5.71' Storage=22 cf Inflow=5.70 cfs 0.446 of = a I I I I 1 15.0" Round Culvert n=0.011 L=10.0' 5=0.0100'/' Oufflow=5.71 cfs 0.446 of o IIIIIIIIII IIIIIIIIIIIIIIIII 0 3/ Link DP-1: Inflow=10.17 cfs 0.788 of _I J L I J L 1-1 L I I -J L I J L 1-1 1 -1 1 L I J L Primary=10.17 cfs 0.788 of 2i Total Runoff Area=2.217 ac Runoff Volume=0.788 of Average Runoff Depth=4.27" i- rt fi -I t -I t -I rt rt 9.89%Pervious=0.219 ac 90.11%Impervious=1.998 ac 1"� illilil i it lillili o 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1516 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Pre_Rev-1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 17 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 18 Summary for Subcatchment EX-1:Subcatchment EX-1 Summary for Subcatchment EX-1 a: Ex Bldg Area Runoff = 2.99 cfs @ 12.08 hrs, Volume= 0.222 af, Depth= 3.89" Runoff = 1.48 cfs @ 12.08 hrs, Volume= 0.120 af, Depth= 4.66" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 10-YR Rainfall=4.90" Type III 24-hr 10-YR Rainfall=4.90" Area(sf) CN Description Area(sf) CN Description 5,720 61 >75%Grass cover,Good,HSG B 13,459 98 Roofs,HSG B 24,110 98 Paved parkinq,HSG B 13,459 100.00%Impervious Area 29,830 91 Weighted Average 5,720 19.18%Pervious Area Tc Length Slope Velocity Capacity Description 24,110 80.82%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment EX-1 a: Ex Bldg Area 6.0 Direct Entry,Ab Hydrograph Subcatchment EX-1:Subcatchment EX-1 Hydrograph I I I I I II I I I I I I I I ■Runoff i I I I I I I IIIIIIIIIII I I I Type III 247hr 1 1 -4 � 1-1 + 1-1 4 4- 1— ■Runoff 1 Q-YR 1�2ainfa117-4.9,0" 3- 1 1 1 1 1 1Type,III�47hf 1 11u IngfflAyrear-113,14591 Sf I 11W-YR RallPfa11: 4.9,0'i 1� I i i I I �gfFi�llunrt�gII.1C�Oiaf I RlungfflAyrea�29,18301sf I I I II Runoff Depthr-4.66" 2_ _1Ru11gffiVplia-mo�II.R2raf— LL I I I I II I I I ITiI min 11 Runoff Depthr-3.891' 1 11 1 DN=98 1 1 1 1 1 1 1 Tc�6101 min 1 11 1 I I 1 _ 1 DN=191_ 1 11 1 1 I I I I I I I I I I I I I II I I I I I I I o 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) o 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Pre_Rev-1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 19 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 20 Summary for Subcatchment EX-2:Subcatchment EX-2 Summary for Subcatchment EX-2a: Ex Bldg Area Runoff = 3.51 cfs @ 12.08 hrs, Volume= 0.268 af, Depth= 4.21" Runoff = 2.19 cfs @ 12.08 hrs, Volume= 0.178 af, Depth= 4.66" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 10-YR Rainfall=4.90" Type III 24-hr 10-YR Rainfall=4.90" Area(sf) CN Description Area(sf) CN Description 3,834 61 >75%Grass cover,Good,HSG B 19,957 98 Roofs,HSG B 29,492 98 Paved parkinq,HSG B 19,957 100.00%Impervious Area 33,326 94 Weighted Average 3,834 11.50%Pervious Area Tc Length Slope Velocity Capacity Description 29,492 88.50%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment EX-2a: Ex Bldg Area 6.0 Direct Entry, Hydrograph Subcatchment EX-2:Subcatchment EX-2 i ■Runoff Hydrograph 219 I + �I+ + + +1- 1 -4 + 1TyReAI24�hr_ s, ■Runoff 2/ I i I I I I I 119-YR IRlinfa117-4.90" I I I I I 1Type,III�47hr 1 1 1 1 1 1 1 1 I I I I I RIu IngffiArgar-119,19571 Sf + 11� le i �'I- I I I I I I I I I I I I I IRunoffIVollume:90.11781af I RlungffiArga:F313,13?61Sf I I I I I I I I I I 1 1 1 1 1 1 Runoff LDepthr-4.667 I IRumfflVlollumq�0.2681af 4- 1-1 1 4- + —1 + 1-1 1-1T�e 6�0+rr♦in- 2i-1-1 T 1-1 7 r -1 T -I + -Runoff-DepthF4-$1 ti• 1 1 1 1 CN=198 LL I 1 1 1 1 TIc:;6L01 min CN=94 ,-�-Irt fill + rl� fi - - IIrt fil I I I I I I I I I I I I I I I I I I I IIIIIIIIII I I o 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Pre_Rev-1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 21 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 22 Summary for Pond EP-1: Ex.Surface Ponding Pond EP-1: Ex.Surface Ponding Hydrograph Inflow Area= 0.994 ac, 86.79%Impervious, Inflow Depth= 4.13" for 10-YR event I I I I I I I I I I I I I I I I I I I I Inflow = 4.46 cfs @ 12.08 hrs, Volume= 0.342 of 6_ ■innew Outflow, = 4.46 cfs @ 12.09 hrs, Volume= 0.342 af, Atten=0%, Lag=0.1 min .asp. �I Id ■Primary Primary = 4.46 cfs @ 12.09 hrs, Volume= 0.342 of /-1-4 t-1� � 1 1 4. Inf qW�►Tef T "Qi� Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs a/ I I I I I I I I I I I I I I I I IP04k1 F;1QV7-5.411 Peak Elev=5.41'@ 12.09 hrs Surf.Area=13 sf Storage=18 cf I I I I 1 11 1 1 1 1 1 IStOlragl@:l:1$ICf Plug-Flow detention time=0.2 min calculated for 0.342 of(100%of inflow) I I I I I I I I I I 1 1 115.0117 Center-of-Mass det.time=0.2 min(774.0-773.8) 3 k6u1nd ICUIV6rt Volume Invert Avail.Storage Storaqe Description o T I T t-1-1 T I-1 T � #1 10.70' 6,946 cf Custom Stage Data(Prismatic)Listed below(Recalc) LL 2 -0'0� IIIIIII 1 II I #2 4.00' 94 cf 4.00'D x 7.50'H Ex.DMH L-L 3.0✓I 7,040 cf Total Available Storage I t_1-1 _L 1-1 -L Elevation Surf.Area Inc.Store Cum.Store 1! I lil it if II (feet) (sq-ft) (cubic-feet) (cubic-feet) 10.70 4 0 0 11.00 627 95 95 0 12.00 13,076 6,852 6,946 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=23.0' RCP,sq.cut end projecting, Ke=0.500 Inlet/Outlet Invert=4.00'/3.90' S=0.0043'P Cc=0.900 n=0.011 Concrete pipe,straight&clean, Flow Area=1.23 sf Primary OutFlow Max=4.44 cfs @ 12.09 hrs HW=5.41' (Free Discharge) t1=Culvert(Barrel Controls 4.44 cfs @ 4.02 fps) M201051_Pre_Rev-1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Pre_Rev-1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 23 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 24 Summary for Pond EP-2:Ex Surface Ponding Pond EP-2: Ex Surface Ponding Inflow Area= 1.223 ac, 92.80%Impervious, Inflow Depth= 4.38" for 10-YR event Hydrograpn IIIIIIIIIIIIIIIIIIII I Inflow = 5.70 cfs @ 12.08 hrs, Volume= 0.446 of /�.- - - ■mnew Outflow, = 5.71 cfs @ 12.08 hrs, Volume= 0.446 af, Atten=0%, Lag=0.0 min I I I I I I I I I ■Primary Primary = 5.71 cfs @ 12.08 hrs, Volume= 0.446 of 1 1 1 1 1 1 s I�flpyv ►� aT11.2 2 �c1 Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs e/ I I I I I I I I I I I I I I I I IP04k1 F'10V:Fa•71 Peak Elev=5.71'@ 12.09 hrs Surf.Area=13 sf Storage=22 cf -I 1 1-1 1 1 J-1--A _�_ -I$xolrage:F224cf_ Plug-Flow detention time=0.2 min calculated for 0.446 of(100%of inflow) ai I I I I I I 1 1 115.O17 Center-of-Mass det.time=0.2 min(764.0-763.8) i-I-4 I4 +- I-I I f-I-4 ♦-I--1 4- I-RdUlridCd1V6rt Volume Invert Avail.Storage Storaqe Description I I I I I I I I I 1 1 1 1 1 1 1 1 1 1 1 6_�0 011 #1 4.00' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder LL i-1-1 r 1-1 T- 1 1 rt r I I-I rt 1-1 -r- L-11 I-I t l-I rt rJ� r #2 7.50' 4,935 cf Custom Stage Data(Irregular)Listed below(Recalc) 2� O.0 4,979 cf Total Available Storage 17 1 1 T 1 1 1 1-7 1 1 1 _F liVTUIaU Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area 1i (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 7.50 4 8.0 0 0 4 8.00 556 93.0 101 101 688 0 9.00 11,424 471.0 4,833 4,935 17,655 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=10.0' RCP,sq.cut end projecting, Ke=0.500 Inlet/Outlet Invert=4.00'/3.90' S=0.0100'P Cc=0.900 n=0.011 Concrete pipe,straight&clean, Flow Area=1.23 sf Primary OutFlow Max=5.67 cfs @ 12.08 hrs HW=5.70' (Free Discharge) t1=Culvert(Barrel Controls 5.67 cfs @ 4.62 fps) M201051_Pre_Rev-1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Pre_Rev-1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 25 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 26 Summary for Link DP-1: Time span=0.00-30.00 hrs,dt=0.02 hrs,1501 points Runoff by SCS TR-20 method,UH=SCS,Weighted-CN Inflow Area= 2.217 ac, 90.11%Impervious, Inflow Depth= 4.27" for 10-YR event Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Inflow = 10.17 cfs @ 12.08 hrs, Volume= 0.788 of Primary = 10.17 cfs @ 12.08 hrs, Volume= 0.788 af, Atten=0%, Lag=0.0 min SubcatchmentEX-1:SubcatchmentEX-1 Runoff Area=29,830 sf 80.82%Impervious Runoff Depth=5.15" Tc=6.0 min CN=91 Runoff=3.90 cfs 0.294 of Primary outflow=Inflow,Time Span=0.00-30.00 hrs,dt=0.02 hrs SubcatchmentEX-1a:Ex Bldg Area Runoff Area=13,459 sf 100.00%Impervious Runoff Depth=5.96" Link DP-1: Tc=6.0 min CN=98 Runoff=1.88 cfs 0.154 of Hydrograph SubcatchmentEX-2:SubcatchmentEX-2 Runoff Area=33,326 sf 88.50%Impervious Runoff Depth=5.49" /-I 1 1 1 1 1 1- 1 1 1 1 -4 �-1 4- 1- - Tc=6.0 min CN=94 Runoff=4.51 cfs 0.350 of ❑Inflow 11/ z_1 1 L I J L I-1 1 0 101- L I J L 1-1 1 Le 1 1 L I!�J L 1-1 -L 11 Primary SubcatchmentEX-2a:Ex Bldg Area Runoff Area=19,957 sf 100.00%Impervious Runoff Depth=5.96" 10/ -I J L I J L 1-1 1 L I J SIP-WTA T T4 92 217 414 Tc=6.0 min CN=98 Runoff=2.78 cfs 0.228 of I J L 11 L 1-1 1 L I J L 1-1 1 1-1 1 L I J L 1-1 1 Pond EP-1:Ex.Surface Ponding Peak EIev=5.80' Storage=23 cf Inflow=5.77 cfs 0.448 of 15.0" Round Culvert n=0.011 L=23.0' S=0.0043'/' Outflow=5.78 cfs 0.448 of Pond EP-2:Ex Surface Ponding Peak EIev=6.15' Storage=27 cf Inflow=7.29 cfs 0.578 of 15.0" Round Culvert n=0.011 L=10.0' 5=0.0100'/' Out low=7.29 cfs 0.578 of a _IIIIIIIII IIIIIIIIIIIIII s 5i - - - - _ - - - - - - - - - - - - Link DP-1: Inflow=13.07 cfs 1.026 of LL 4 Primary=13.07 cfs 1.026 of -( IIIIIIIII IIIIIIIIIIIIII 3j - - - - _ - - - - - - - - - - - Total Runoff Area=2.217 ac Runoff Volume=1.026 of Average Runoff Depth=5.55" 9.89%Pervious=0.219 ac 90.11%Impervious=1.998 ac 1� 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type/1/24-hr 25-YR Rainfall=6.20" M201051_Pre_Rev-1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 27 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 28 Summary for Subcatchment EX-1:Subcatchment EX-1 Summary for Subcatchment EX-1 a:Ex Bldg Area Runoff = 3.90 cfs @ 12.08 hrs, Volume= 0.294 af, Depth= 5.15" Runoff = 1.88 cfs @ 12.08 hrs, Volume= 0.154 af, Depth= 5.96" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 25-YR Rainfall=6.20" Type III 24-hr 25-YR Rainfall=6.20" Area(sf) CN Description Area(sf) CN Description 5,720 61 >75%Grass cover,Good,HSG B 13,459 98 Roofs,HSG B 24,110 98 Paved parkinq,HSG B 13,459 100.00%Impervious Area 29,830 91 Weighted Average 5,720 19.18%Pervious Area Tc Length Slope Velocity Capacity Description 24,110 80.82%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment EX-1 a: Ex Bldg Area 6.0 Direct Entry,Ab Hydrograph Subcatchment EX-1:Subcatchment EX-1 �_ _ _II l II I ❑Runoff Hydrograph 2 I 1 1 lee ms 1 1 1 1 1 1 i 1 1 1 1 1 1 I I I I I Type III 247hr 4/-1-1 T- 1-1 T L 1-1 -11y. -T I I -f r 1-1 T I—I-T 7 I— .Runoff 1 2�-YR Rzjinfa117-6.1O" I I I I I I I I I I I I I Type,III�41hr 1 1 1 11 1 1 1RlungfflAyrgar-113,14591Sf I I I I I I I I 1 1 1 12�-XR IR1irjfall�C.�0'i I I I I I I 11 1 1RunofflVpllume=0.11541af �3 -I IRNnQffAr-fa-:M,ilI - - - -1 1 L 1-1 L -L L 1-1 1 1-Runaff-Depthr5.96"- I I I I I I I I I I I I I IRunoffIVollime:90.2941af I I I I I I I I I I ITc=6L0 min I I I I I I I I I I I I I 1_iRunoff lDelpthr-5.1151'_ I I I I I I I I I I I I LL 2� 1 1 1 1 1 1 1 1 1 1 1 1 1 _ 1 1 TIC oUl min I 1 1 I I I I I I I I I I I I I I I I I I I I I CN=191 _1-1 L 11 1 LIA L 111 L I- 1� I I I I I I I I I I I I 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 - 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type/1/24-hr 25-YR Rainfall=6.20" M201051_Pre_Rev-1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 29 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 30 Summary for Subcatchment EX-2:Subcatchment EX-2 Summary for Subcatchment EX-2a: Ex Bldg Area Runoff = 4.51 cfs @ 12.08 hrs, Volume= 0.350 af, Depth= 5.49" Runoff = 2.78 cfs @ 12.08 hrs, Volume= 0.228 af, Depth= 5.96" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 25-YR Rainfall=6.20" Type III 24-hr 25-YR Rainfall=6.20" Area(sf) CN Description Area(sf) CN Description 3,834 61 >75%Grass cover,Good,HSG B 19,957 98 Roofs,HSG B 29,492 98 Paved parkinq,HSG B 19,957 100.00%Impervious Area 33,326 94 Weighted Average 3,834 11.50%Pervious Area Tc Length Slope Velocity Capacity Description 29,492 88.50%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment EX-2a: Ex Bldg Area 6.0 Direct Entry, Hydrograph Subcatchment EX-2:Subcatchment EX-2 1-I 1 L _I -1 L I_I L -i- L Hydrograph s� I . I I I I I I I I I ❑Runoff I-I L I 1 rt r-I-I T -I - t- 1-I I rt L I I I I I I I Type III 247hr 5- 1 451 1 1 •Runoff 1 1 1 1 1 1 12�-�(R Rzjirlfall7-6.�O" I I I I Type,III�47hr 1—I -Au inQffiArear-119,1957�Sf 4-' 1 1 1 1 1 1 12�-YR Rzjinfall: f§.�Ori 2—� 1 1 1 iRunoffIVQllurnegO.2281af I I I 1 1 1 1RlunpfflArpar-313,134ISt _ I 1 1 1 1 1 I Runoff Depth7-5.96" s -1-� T 1-1 7 F I I - F- 1-1 Ru"QfWoIiu11n$:90-335OTaf TcT6LO min I I I I I I I I I I I 1 1 Runoff Depthr-51.497 1- 1 4 1-1 1-1 -4 4- 1-1 I—CAI=98- -1-4 -L 1-1 -L --I .I l-1—I -L 1-1 L- 1-1 Tc:;6LO1 rain- 1 1 CN=94 IIIIIIIIII IIIIIIIIIIIIIIII I IIIIII I I 7 Fi—i T 1 F 1 1 1 1 1 1 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type/1/24-hr 25-YR Rainfall=6.20" M201051_Pre_Rev-1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 31 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 32 Summary for Pond EP-1: Ex.Surface Ponding Pond EP-1: Ex.Surface Ponding Hydrograph Inflow Area= 0.994 ac, 86.79%Impervious, Inflow Depth= 5.40" for 25-YR event / I I I I I I I I I I I I I I I I I I I I Inflow = 5.77 cfs @ 12.08 hrs, Volume= 0.448 of / — — _ ■i"new Outflow, = 5.78 cfs @ 12.08 hrs, Volume= 0.448 af, Atten=0%, Lag=0.0 min ' I I I I I I I ». I I I I I I I I I I I I I I I I I 10 Primary Primary = 5.78 cfs @ 12.08 hrs, Volume= 0.448 of 6—/ 1 1 1 1 1 1 1 1 5 e �f�flpylr��ep7q.994 pci Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs IFgi k1 F'IQIV:5-$01 Peak Elev=5.80'@ 12.08 hrs Surf.Area=13 sf Storage=23 cf e 1 L L I_J L 11 L I L 1 L L 1 J L I IStolrage:231cf_ Plug-Flow detention time=0.2 min calculated for 0.447 of(100%of inflow) a 1 1 1 1 1 1 115.017 Center-of-Mass det.time=0.2 min(768.1-767.9) i-4 r L _i k--1- 1 4- I-R6uIn"WV6& Volume Invert Avail.Storage Storaqe Description o 3 6=J0.011 #1 10.70' 6,946 cf Custom Stage Data(Prismatic)Listed below(Recalc) LL — rt L 1-1 fi 1 1 t l rt r l fi l—I t l—I rt r rt #2 4.00' 94 cf 4.00'D x 7.50'H Ex.DMH L-23.0 7,040 cf Total Available Storage IIII IIIIIIII I Elevation Surf.Area Inc.Store Cum.Store 1i (feet) (sq-ft) (cubic-feet) (cubic-feet) 10.70 4 0 0 11.00 627 95 95 0 1111111 12.00 13,076 6,852 6,946 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours( Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=23.0' RCP,sq.cut end projecting, Ke=0.500 Inlet/Outlet Invert=4.00'/3.90' S=0.0043'P Cc=0.900 n=0.011 Concrete pipe,straight&clean, Flow Area=1.23 sf Primary OutFlow Max=5.75 cfs @ 12.08 hrs HW=5.79' (Free Discharge) t1=Culvert(Barrel Controls 5.75 cfs @ 4.69 fps) M201051_Pre_Rev-1 Type/1/24-hr 25-YR Rainfall=6.20" M201051_Pre_Rev-1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 33 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 34 Summary for Pond EP-2:Ex Surface Ponding Pond EP-2: Ex Surface Ponding Inflow Area= 1.223 ac, 92.80%Impervious, Inflow Depth= 5.67" for 25-YR event Hydrograph + + + � + Inflow = 7.29 cfs @ 12.08 hrs, Volume= 0.578 of +1-1 1-1 + I-I _+ I+ I 1-1 + -1 + 1-4� ■i"new Outflow, = 7.29 cfs @ 12.09 hrs, Volume= 0.578 af, Atten=0%, Lag=0.1 min 8- 1 1 1 1 1 1 1 1 72- 1 1 1 1 1 1 1 1 1 1 1 1 1 1 10 Primary Primary = 7.29 cfs @ 12.09 hrs, Volume= 0.578 of �I�flpylr�►�e�aTfi.?12 �� Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs i- rt 1-1-1 t- 1-1t I r I-t r 1-1 fi IFlopkI€11eW74 5r Peak Elev=6.15'@ 12.09 hrs Surf.Area=13 sf Storage=27 cf 6- I I -I I _1 1 1 1 1 1 Istolrawe:27id Plug-Flow detention time=0.2 min calculated for 0.578 of(100%of inflow) 5� 1 1 1 1 1 1 115.O11 Center-of-Mass det.time=0.2 min(758.8-758.6) /- 17 r 1-1 r 1-1 T 1 7 1_T r 1-1 r 1 RC_Ju1nd7CJjI1VJrf_ Volume Invert Avail.Storage Storaqe Description ; 4 #1 4.00' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder �'� r LL 3� I I I I I I I I 1 1 1 1 1 1 1 1 1 1 1 1 1 �J I ✓I #2 7.50' 4,935 cf Custom Stage Data(Irrequiar)Listed below(Recalc) _ _ _ 4,979 cf Total Available Storage 17 1 1 1 1 1 1 to O �OI� � II I Elevation Surf Area Perim. Inc.Store Cum.Store Wet.Area 1- 1-A _ Iq 1 (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 1 7.50 4 8.0 0 0 4 8.00 556 93.0 101 101 688 0 9.00 11,424 471.0 4,833 4,935 17,655 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 z3 24 25 26 27 28 29 30 Time(hours) Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=10.0' RCP,sq.cut end projecting, Ke=0.500 Inlet/Outlet Invert=4.00'/3.90' S=0.0100'P Cc=0.900 n=0.011 Concrete pipe,straight&clean, Flow Area=1.23 sf Primary OutFlow Max=7.25 cfs @ 12.09 hrs HW=6.13' (Free Discharge) t1=Culvert(Inlet Controls 7.25 cfs @ 5.91 fps) M201051_Pre_Rev-1 Type///24-hr 25-YR Rainfall=6.20" M201051_Pre_Rev-1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 35 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 36 Summary for Link DP-1: Time span=0.00-30.00 hrs,dt=0.02 hrs,1501 points Runoff by SCS TR-20 method,UH=SCS,Weighted-CN Inflow Area= 2.217 ac, 90.11%Impervious, Inflow Depth= 5.55" for 25-YR event Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Inflow = 13.07 cfs @ 12.08 hrs, Volume= 1.026 of Primary = 13.07 cfs @ 12.08 hrs, Volume= 1.026 af, Atten=0%, Lag=0.0 min SubcatchmentEX-1:SubcatchmentEX-1 Runoff Area=29,830 sf 80.82%Impervious Runoff Depth=7.81" Tc=6.0 min CN=91 Runoff=5.77 cfs 0.446 of Primary outflow=Inflow,Time Span=0.00-30.00 hrs,dt=0.02 hrs SubcatchmentEX-1a:Ex Bldg Area Runoff Area=13,459 sf 100.00%Impervious Runoff Depth=8.66" Link DP-1: Tc=6.0 min CN=98 Runoff=2.70 cfs 0.223 of Hydrograph SubcatchmentEX-2:SubcatchmentEX-2 Runoff Area=33,326 sf 88.50%Impervious Runoff Depth=8.18" /-I L L I J L 1-1 1 L I -L L I J I i owl- Tc=6.0 min CN=94 Runoff=6.58 cfs 0.521 of 14i /-1-4 t- I A 4- 1 1 t +3m�. t 1 11 4 �11-4 1 1 - °Primary SubcatchmentEX-2a:Ex BldgArea Runoff Area=19,957 sf 100.00%Impervious Runoff Depth=8.66" 13% i- t t I t I t 30 '"Tr� r2 1� q6 Tc=6.0 min CN=98 Runoff=4.00 cfs 0.331 of 12� IIII1 7 1 111 11111111111111111 j _ - - - - - - - - - - - - - - - - - Pond EP-1:Ex.Surface Ponding Peak Elev=6.67' Storage=34 cf Inflow=8.47 cfs 0.669 of 11 I I I I I I I I I I 1 1 11 1 11 1 11 1 1 11 1 15.0" Round Culvert n=0.011 L=23.0' S=0.0043'/' Outflow=8.46 cfs 0.669 of yj -1-4 1--A 4- 1-1 4- 1-4 4- 1-1 + 1-1 4 1-4 4-- 1-1 + Pond EP-2:Ex Surface Ponding Peak Elev=7.76' Storage=62 cf Inflow=10.58 cfs 0.852 of 8! /-I t t 1-1 t l I t t fi 1 1 t 1 1 fir I t fi 1 1 t 15.0" Round Culvert n=0.011 L=10.0' 5=0.0100 T Outflow=10.47 cfs 0.852 of a T I_I I_I I_I I_I I_I Link DP-1: Inflow=18.89 cfs 1.521 of LL 6� Primary=18.89 cfs 1.521 of 4i - -I - -I -I -I Total Runoff Area=2.217 ac Runoff Volume=1.521 of Average Runoff Depth=8.23" 1-1-1 t 1-1 t I--I fi 1-1 t 1-1 rt r-I--t 1- 1-1 t 9.89%Pervious=0.219 ac 90.11%Impervious=1.998 ac 2� i t i 1 i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type///24-hr 100-YR Rainfall=8.90" M201051_Pre_Rev-1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 37 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 38 Summary for Subcatchment EX-1:Subcatchment EX-1 Summary for Subcatchment EX-1 a: Ex Bldg Area Runoff = 5.77 cfs @ 12.08 hrs, Volume= 0.446 af, Depth= 7.81" Runoff = 2.70 cfs @ 12.08 hrs, Volume= 0.223 af, Depth= 8.66" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 100-YR Rainfall=8.90" Type III 24-hr 100-YR Rainfall=8.90" Area(sf) CN Description Area(sf) CN Description 5,720 61 >75%Grass cover,Good,HSG B 13,459 98 Roofs,HSG B 24,110 98 Paved parkinq,HSG B 13,459 100.00%Impervious Area 29,830 91 Weighted Average 5,720 19.18%Pervious Area Tc Length Slope Velocity Capacity Description 24,110 80.82%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment EX-1 a: Ex Bldg Area 6.0 Direct Entry,Ab Hydrograph Subcatchment EX-1:Subcatchment EX-1 3 -I -T L I—I I ❑R""off Hydrograph . I I i I I I I I I I I I I I I I I I I I I I I I I I I I I I L 1 1 (Type III 247hr 6� 1-1 1 s.n. L —� T L - L 1-1 T 1-1 1 — ■Runoff 0-YR 9.11 91117-8.9,0" I I I I I I I I I I I I I I I I 1 1 (Type,III�47hr —1- t 1-1 t t 1-1 1 lnelfftArear-113,14591 Sf 5-- 1 1 1 1 1 1 1 1 1 1 1 1 1 1 111�Q 1R i ��� •�'Ir 2 1 1 1 1 1 1 1 1 1 1 OfflVplluMe�0.2231af 1 I I I_I IRungfflAlrga�29,18301sf I I I I I I I I I I Runoff Depth7-8.66" 4� 1 1 1 1 1 1 1 1 1 1 1 1 1 1RumfflVollume:90.1446W LL 1 1 I I I I I II I I I 1Tc=6L0 min —I _ 1 —' I_ — — Welpth�71.81T_ 1�-I� t 1-1 t i-I 1 1 I -t i- 1-1 t I-I=98 LL 3� I I I I I I I I I I ' I I I I I I 1 1 TIC o610i min 11L1 1LLIJL — L —IL1-1LLI 11ICNJ91_ 2� IIIIIIIIII III - IIIIII 1�-1-4 � 1-14 �1� -k 14- 1-1 — LI 1 4 ' I! 6 III 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type///24-hr 100-YR Rainfall=8.90" M201051_Pre_Rev-1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 39 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 40 Summary for Subcatchment EX-2:Subcatchment EX-2 Summary for Subcatchment EX-2a: Ex Bldg Area Runoff = 6.58 cfs @ 12.08 hrs, Volume= 0.521 af, Depth= 8.18" Runoff = 4.00 cfs @ 12.08 hrs, Volume= 0.331 af, Depth= 8.66" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 100-YR Rainfall=8.90" Type III 24-hr 100-YR Rainfall=8.90" Area(sf) CN Description Area(sf) CN Description 3,834 61 >75%Grass cover,Good,HSG B 19,957 98 Roofs,HSG B 29,492 98 Paved parkinq,HSG B 19,957 100.00%Impervious Area 33,326 94 Weighted Average 3,834 11.50%Pervious Area Tc Length Slope Velocity Capacity Description 29,492 88.50%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment EX-2a: Ex Bldg Area 6.0 Direct Entry, Hydrograph Subcatchment EX-2:Subcatchment EX-2 i I I I I I I I I I I I I I ■Runoff Hydrograph 4,- --a I-1 + 1 A ,0o ms 4 1-1 + I-I -4 4- 1-1 1 _ I I I I I I I I I I I I I Type III 247hr 7-� s.� ■Runoff 11109-YR 9.1infal17-8.90" -I-A 1-1 4 1 - + 1 1 4 ITYROJI 447rr 3-� -I-1 r 1-1 rt r 1-1 T rt r 1-1 -tRlunoff Arear-119,1957TSf- 6� I I I I I I I I I I I 11109-YR 9-11 -111�:4-9,0'i I I I I I I 1RunofflVollurneg0.3311af 5�-1-1 T F 1 T 1 I F 1 1 -Runq"rea7-j3,l346-Sf- ( I I I I I Runoff De'pthr-8.66" 1 1 I I IRunoff1V1o11ume:90.1521Iaf LL 2-' I i 1 1 1 1 1-1-1 1 1 1 1 1 I 1 1 1 1 1 1TIC*6L0 min 4-� 1 1 Runoff Depthr-8.1187 CN=98 -1--4 + 1-1 + 1--A I 1-1-1 + 1-14 + 1-1TIc*&(0r3in- 3/ I I I I I I I I I I I I I I I CN=94 2-- 1 F 1-11 1 IIIIIIIIIIIIIIII II II II IIII I_I I_I I_I I_I I_I °0 1 z 34 ee i s s 1oii 1'z � 1� 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 - 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Pre_Rev-1 Type///24-hr 100-YR Rainfall=8.90" M201051_Pre_Rev-1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 41 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 42 Summary for Pond EP-1: Ex.Surface Ponding Pond EP-1: Ex.Surface Ponding Hydrograph Inflow Area= 0.994 ac, 86.79%Impervious, Inflow Depth= 8.08" for 100-YR event I I I I I I I I I I I I I I I I I I I I I I—I I I Inflow = 8.47 cfs @ 12.08 hrs, Volume= 0.669 of �- — — — — — — — — ■inn.. Outflow, = 8.46 cfs @ 12.09 hrs, Volume= 0.669 af, Atten=0%, Lag=0.1 min 9yI I I I I .47n. 1 1 1 1 1 1 1 1 11 1 1 1�}1 p1p 11 1 ■Primary Primary = 8.46 cfs @ 12.09 hrs, Volume= 0.669 of a� If#19 Te7 - " f i Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs Peak Elev=6.67'@ 12.09 hrs Surf.Area=13 sf Storage=34 cf /-1-4 4-1-4 4- 1-1 1 1- 1 1 IStOlrager341cf- Plug-Flow detention time=0.2 min calculated for 0.668 of(100%of inflow) s/ —I 1 1 11 1 1 11 1 11 1 11 1 J b_017 Center-of-Mass det.time=0.2 min(759.9-759.8) 5 j / 1 1 11 1 1 1 1 1 1 �l 'C_ �tdun1Ilvrt _ Volume Invert Avail.Storage Storaqe Description o _ _ 1 1 _ _1 I I _ _ 1 1 _ _1 1 1 11 6J0.0-11 #1 10.70' 6,946 cf Custom Data Stage (Prismatic)Listed below Rlc LL 4� g ( ow( eca ) i I7 rl-1 T- l I T I -7 i I-1 T I I T I r #2 4.00' 94 cf 4.00'D x 7.50'H Ex.DMH 3i L-23.0.0 7,040 cf Total Available Storage /-1-4 �-I-4 1-1 + 1 1 1- 1--� 4- 1—I 2-� _ J LIJ LI_I 1 11J LI_I1 11 iJ. I Elevation SurF.Area Inc.Store Cum.Store i (feet) (sq-ft) (cubic-feet) (cubic-feet) 1% 10.70 4 0 0 11.00 627 95 95 0 12.00 13,076 6,852 6,946 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=23.0' RCP,sq.cut end projecting, Ke=0.500 Inlet/Outlet Invert=4.00'/3.90' S=0.0043'P Cc=0.900 n=0.011 Concrete pipe,straight&clean, Flow Area=1.23 sf Primary OutFlow Max=8.41 cfs @ 12.09 hrs HW=6.65' (Free Discharge) t1=Culvert(Inlet Controls 8.41 cfs @ 6.85 fps) M201051_Pre_Rev-1 Type///24-hr 100-YR Rainfall=8.90" M201051_Pre_Rev-1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Pace 43 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 44 Summary for Pond EP-2:Ex Surface Ponding Pond EP-2: Ex Surface Ponding Inflow Area= 1.223 ac, 92.80%Impervious, Inflow Depth= 8.36" for 100-YR event Hydrograpn IIIIIIIIIIIIIIIIIIIIII - - - - I Inflow = 10.58 cfs @ 12.08 hrs, Volume= 0.852 of ■mnow Outflow, = 10.47 cfs @ 12.09 hrs, Volume= 0.852 af, Atten=1%, Lag=0.5 min ' +osa�. y ■Pnmary Primary = 10.47 cfs @ 12.09 hrs, Volume= 0.852 of 11/ ' ,e<rlI Ilnf�P�faTep:f _.19"�qf Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs IP��kI�rV �J Peak Elev=7.76'@ 12.09 hrs Surf.Area=191 sf Storage=62 cf ' I I I I I I I I I I T I IStorageiQZIcf 8 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Plug-Flow detention time=0.1 min calculated for 0.851 of(100%of inflow) ' I 1 1 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 115.017 Center-of-Mass det.time=0.1 min(751.7-751.6) '9 _ II_ I III 1 11111 _11 Rdl�n�rit1111/6rt IIII Volume Invert Avail.Storage Storaqe Description 11J0.&11- #1 4.00' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder 6' ' L ✓ #2 7.50' 4,935 cf Custom Stage Data(Irregular)Listed below(Recalc) 4i - - - -L - -�0,0 4,979 cf Total Available Storage 3� '- -I I I I I I-I I I-I II I I 1 1, 10104�01 Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area z - - - - - - - - - - - - - - (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) ' 1 7.50 4 8.0 0 0 4 8.00 556 93.0 101 101 688 9.00 11,424 471.0 4,833 4,935 17,655 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=10.0' RCP,sq.cut end projecting, Ke=0.500 Inlet/Outlet Invert=4.00'/3.90' S=0.0100'P Cc=0.900 n=0.011 Concrete pipe,straight&clean, Flow Area=1.23 sf Primary OutFlow Max=10.41 cfs @ 12.09 hrs HW=7.73' (Free Discharge) t1=Culvert(Inlet Controls 10.41 cfs @ 8.48 fps) M201051_Pre_Rev-1 Type///24-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 45 Summary for Link DP-1: Inflow Area= 2.217 ac, 90.11%Impervious, Inflow Depth= 8.23" for 100-YR event Inflow = 18.89 cfs @ 12.09 hrs, Volume= 1.521 of Primary = 18.89 cfs @ 12.09 hrs, Volume= 1.521 af, Atten=0%, Lag=0.0 min Primary outflow=Inflow,Time Span=0.00-30.00 hrs,dt=0.02 hrs Link DP-1: Hydrograph T T 17 T 1-1 T I-1 T 1-1 T T 1-1 T_ 1-1 7 r 1 T T z1 - + Fowl— i-1� + 1-1 + 009 h + 1 1—� + +I + 1 �+ + ❑Primary 20� —10.09 de — is- ;-1-4 �1-1 4- 1-1 + 1 #�1�P I�r�' 7:44 18� n! '-1-t t- I-� -L1-14 LI-j 1- 1-1 + 1-1 -t �-I-1 4- I-1 ;5✓ -1- TI] T -1 T FIT T I-1 T 1-17 [IT TI] T ;s% i=�rtfiI� fil=I — -l- — l=1 + =1 — —l- — _ - i- i-1-1 t l—I t t-I--I 1- 1—I + 1-1 fi �-l--i 1- 1—I t e -17TI] 7 -1T _I7T1-1T1-17 [ITTI] T 5 %-irtrl� -1rt - - l-i - -l - - - - -ir 4 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) APPENDIX E: PROPOSED CONDITIONS HYDROLOGIC ANALYSIS ➢ PROPOSED CONDITIONS DRAINAGE MAP ➢ PROPOSED CONDITIONS HYDROCAD CALCULATIONS SA N ar u -- CONCRffE S pEWNK __ �� n/j �p(/ wl w � B( VgRIAB[E WIDTH a II _ _ ST EET !_ YJ IT 9 N86.5020T Te a ul _J rc \ w a e�W E up - wl,�a�'�r lap .e. wlaar �He'gL7Es w)sp Q��w)sp �rc u zmzm e B SB/DN w m w r tD w> ?'1'S• / DAY zsswy n.rir __ a• T8M-1 �FNO) m-w W_;m s� � �Sr u9r COAC'REfE SA71EwNK wlap�\- / � ®wrus >z cJ w mj 0. p 0F j lau �marc� S i i 1� c$� U Z 2 Q<1 p d 9 • ^y �-e — cts_ nr 1 zgoc�wZ z y D. S < Q wIS,17 lar wraa} y O g Q. \ _ rICK PAYER /4 lc� _ Inc1� rE(EriBAfW --. \ wlS�p •.x19 Now or Fomtpj, II // - tLA41E -- _-- C MONWEq(TyOF \ / �9.!• INFILTRATION ��'%ADrr ' RE oATEREv/slonrs SS4CHSUET/S \ / a t ar nn. SYSTEM #1 oMMERr DE/ENIKhV BASIN DELINFAIION J\ \ 1Y,/ Atl YyS, r II JC _ nd1' O I `�J• U Millis PERFORMED BY EPSILON _ ASSOCIATES IN OCTOBER OF / i O A N` IAA\°a_!tD� -- '/ 'hk� � $ 1 fiz / v _---- \ PR-1 a - /1Y /'!BO'W 7L%D Bum \\ --below. Call I You dig. ALWAYS CALL 811 -JIM r P R-2 a' \ It's fast.It's free.It's the law. \ 100'117UND BUS y y FOR CONCEPT PURPOSES ONLY / R ep 1�is, � DRnwx er:°�xnExrx.nxoE°.n.�w cin ox v usnixwcareoomemvine xcv51 BOOK ftr CL Now�i }}} \ / DATE: 05/06/2021 O \\ / CHECKED BY: zLR to• \ , am CM-?CON .nb^Y� J \\\ / \ CAD LD.: M201051CVL-0 wI4S ®pAY, DOC 41 ' 1 ` PROJECT' 1 DOD I \\ LOG'/715?' _ \- an \ tv \ PROPOSED SITE \ `"�' \ PLAN DOCUMENTS \�%� - \ INFILTRATION rARFA_Iin "' � y FOR 5 5O'wET(,WD SYSTEM#2 �.» .5 , � 1 r ��y` D P 1 BERKELEY v_toJ \\ PR-2 \ —' t \ �"'m^gyp' / INVESTMENTS, \ aMVpa e-tu V-1o4 \ / �' \\ � � / �E � en w � INC. PROPOSED DEVELOPMENT V-105 �\\ \-\\`�a � \ \ -/�. / \ \ \\ ` ?Z ..+r \ y. �' 64 PLEASANT STREET \\ CDAL^, 9: • W TOWN OF WATERTOWN BY EPSILONASSOCATES PERFORMED t>-122 V-1Q� \\�\ \ \ `-� \� _ \ - NOw Or Form MIDDLESEX COUNTY, \ �� MASSACHUSETTS ocroBEROFza,a. � rf\.e \ ��\ \ 6_ —.a--__-- �: \ - CROSSRgt� L[C &NK DELNEAININ PERFORMED \\\ \\�\ \ \' \` / \ _ CFRT 2470,51 BY EPSaON ASSOOF 2 /N �� �: ,e .\ P- L`�'7'520 B 0 H L E R// OCTOBER OF 2076. \ s, \ \ \ 45 FRANKLIN STREET,Sth FLOOR \\ R IV\ c)\,�_\� I� y� Pnooe: (snl aas-soao /r' '`\\w 16 www.BohlerEngineering.com \ /` .`\� f �cy'�ry"�' eta,J' _ \\\�rqp \ • alsU_,SOF w 11' \\\\\\ \ \ \� //� Maw or Fossmm77' 241 LOT 2 w 9z.y; �° \ S EETTITLE PROPOSED CONDITIONS s �\,` O •� — _ — WATERSHED MAP ch/ \ 3 F SHEET NUMBER ORG.DATE-05106/2021 a I ! M2O1051_Post_Rev1 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 2 Area Listing(all nodes) Area CN Description (acres) (subcatchment-numbers) 0.200 61 >75%Grass cover,Good,HSG B (PR-1,PR-2) 1.250 98 Paved parking,HSG B (PR-1,PR-2) 0.767 98 Roofs,HSG B (PR-1a,PR-2a) 2.217 95 TOTAL AREA PR-1 PR-1a PR-2 PR-2a Project Are #1 Ex. Bldg Area Project Are #2 E Bldg Area 1P 2P Infiltration System 1 I 'tration System#2 DP-1 Subcat Reach on Link I Routing Diagram for M201051_Post_Rev1 Prepared by Bohler Engineering, Printed 5/4/2021 HydroCAD®10.00-19 s/n 08955 0 2016 HydroCAD Software Solutions LLC M201051_Post_Rev1 M201051_Post_Rev1 Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD®10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 3 HvdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 4 Soil Listing(all nodes) Ground Covers(all nodes) Area Soil Subcatchment HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment (acres) Group Numbers (acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers 0.000 HSGA 0.000 0.200 0.000 0.000 0.000 0.200 >75%Grass cover,Good PR-1, 2.217 HSG B PR-1,PR-1a,PR-2,PR-2a PR-2 0.000 HSG C 0.000 1.250 0.000 0.000 0.000 1.250 Paved parking PR-1, 0.000 HSG D PR-2 0.000 Other 0.000 0.767 0.000 0.000 0.000 0.767 Roofs PR-1a, 2.217 TOTAL AREA PR-2a 0.000 2.217 0.000 0.000 0.000 2.217 TOTAL AREA M201051_Post_Rev1 M201051_Post_Rev1 Type/I/24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD®10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 5 HvdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 6 Pipe Listing(all nodes) Time span=0.00-30.00 hrs,dt=0.02 hrs,1501 points Runoff by SCS TR-20 method,UH=SCS,Weighted-CN Line# Node In-Invert Out-Invert Length Slope n Diam/Width Height Inside-Fill Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Number (feet) (feet) (feet) (ft/ft) (inches) (inches) (inches) SubcatchmentPR-1:Project Area#1 Runoff Area=29,830 sf 80.84%Impervious Runoff Depth=2.26" 1 1 P 4.00 3.90 23.0 0.0043 0.013 15.0 0.0 0.0 Tc=6.0 min CN=91 Runoff=1.78 cfs 0.129 of 2 2P 4.00 3.90 10.0 0.0100 0.013 15.0 0.0 0.0 SubcatchmentPR-1a:Ex.Bldg Area Runoff Area=13,459 sf 100.00%Impervious Runoff Depth=2.97" Tc=6.0 min CN=98 Runoff=0.96 cfs 0.076 of SubcatchmentPR-2:Project Area#2 Runoff Area=33,326 sf 90.99%Impervious Runoff Depth=2.64" Tc=6.0 min CN=95 Runoff=2.24 cfs 0.169 of SubcatchmentPR-2a:Ex Bldg Area Runoff Area=19,957 sf 100.00%Impervious Runoff Depth=2.97" Tc=6.0 min CN=98 Runoff=1.42 cfs 0.113 of Pond 1 P:Infiltration System#1 Peak EIev=10.48' Storage=1,468 cf Inflow=2.74 cfs 0.205 of Discarded=0.03 cfs 0.055 of Primary=2.73 cfs 0.130 of Outflow=2.76 cfs 0.185 of Pond 2P:Infiltration System#2 Peak EIev=8.45' Storage=1,471 cf Inflow=3.66 cfs 0.282 of Discarded=0.03 cfs 0.058 of Primary=3.63 cfs 0.203 of Oufflow=3.66 cfs 0.262 of Link DP-1: Inflow=6.30 cfs 0.333 of Primary=6.30 cfs 0.333 of Total Runoff Area=2.217 ac Runoff Volume=0.487 of Average Runoff Depth=2.64" 9.03%Pervious=0.200 ac 90.97%Impervious=2.017 ac M201051_Post_Rev1 Type 111 24-hr 2-YR Rainfall=3.20" M201051_Post_Rev1 Type 111 24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 7 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 8 Summary for Subcatchment PR-1:Project Area#1 Summary for Subcatchment PRAa:Ex.Bldg Area Runoff = 1.78 cfs @ 12.09 hrs, Volume= 0.129 af, Depth= 2.26" Runoff = 0.96 cfs @ 12.08 hrs, Volume= 0.076 af, Depth= 2.97" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 2-YR Rainfall=3.20" Type III 24-hr 2-YR Rainfall=3.20" Area(sf) CN Description Area(sf) CN Description 5,716 61 >75%Grass cover,Good,HSG B 13,459 98 Roofs,HSG B 24,114 98 Paved parkinq,HSG B 13,459 100.00%Impervious Area 29,830 91 Weighted Average 5,716 19.16%Pervious Area Tc Length Slope Velocity Capacity Description 24,114 80.84%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment PRAa: Ex.Bldg Area 6.0 Direct Entry,AB Hydrograph Subcatchment PR-1: Project Area#1 i o R"off Hydrograph t/ I I IDeems I I I I I I I I I Type III 247hr em ■R��o6 I I I I I ?-XR IRginfa117-3.?O" I I I I I Type,III 441hr I I I I I I I I I I I I I I I RIu IngfflAyrgar-113,14591 sf I I I I I ?-XR IRaiinfalll:�1-4'i I I I I I I I I I I I I I IRunofflVollurne:90.0761af IRlungfflAyrga:pA9,18$OIs _ I I I I I I I I I I I I I Runoff Depth7-2.97" IRungfflVollumq:90.11291af LL I I I I I I I I I I ITc=6LO min I -r I-Runoff DepthF2.267- CN=198 I I I I I I TIc:;6LO1 min CN=91 I I I I I I I I I I I I I I I I I I I I I I I 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 / -/ /.../ .... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type 111 24-hr 2-YR Rainfall=3.20" M201051_Post_Rev1 Type 111 24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 9 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 10 Summary for Subcatchment PR-2:Project Area#2 Summary for Subcatchment PR-2a:Ex Bldg Area Runoff = 2.24 cfs @ 12.08 hrs, Volume= 0.169 af, Depth= 2.64" Runoff = 1.42 cfs @ 12.08 hrs, Volume= 0.113 af, Depth= 2.97" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 2-YR Rainfall=3.20" Type III 24-hr 2-YR Rainfall=3.20" Area(sf) CN Description Area(sf) CN Description 3,002 61 >75%Grass cover,Good,HSG B 19,957 98 Roofs,HSG B 30,324 98 Paved parkinq,HSG B 19,957 100.00%Impervious Area 33,326 95 Weighted Average 3,002 9.01%Pervious Area Tc Length Slope Velocity Capacity Description 30,324 90.99%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment PR-2a: Ex Bldg Area 6.0 Direct Entry,AB Hydrograph Subcatchment PR-2: Project Area#2 i l l l 1 1 1 .Runoff Hydrograph b, i 1 1 I I I I Type,111 247hr 224 •Ruooff ?-X 1R Rginfall7-1-W, —I J L 1_1 1 L I_ L IJ 1 1_1 -1 L ITYPe111I 947-hf— I I I I I I IRu ingfflAyrgar-119,0$71Sf 2-- 1 1 1 1 1 1 1 1 1 1 1 1 1 ?-YR IRaiinf-111:9.4'i 1-� I I I I I 11 1 RunofflVollumeg0.11131af I I I I I I I I 1 1 1 1RlumgfflArgaF-313,13?61Sf I I I I I 1 I � 1 1 Runoff Depthr-2.977 I I I I I I I I 1 1 IRungff1V1o11ume:90.11691af ° I I I I I I ITc*6L0 min I I I I I I I I I I 1 1 1 1 I Runoff Depthr-2.64ti' 1 1 CN=98 —1-4 1 1--1 1-1 - 1-1TIc:;6L01min 1� I I CN=95 IIIIIIIIII IIII II IIIIIIIII I I I I IIIIII I I o IIIIIIIIII IIII II II II III I 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type Ill 24-hr 2-YR Rainfall=3.20" M201051_Post_Rev1 Type 111 24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 11 HvdroCADO 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 12 Summary for Pond 1 P:Infiltration System#1 Pond 1 P:Infiltration System#1 -Chamber Wizard Field A Inflow Area= 0.994 ac, 86.80%Impervious, Inflow Depth= 2.48" for 2-YR event Chamber Model=ADS_StormTechSC-310+Cap(ADS StormTech@SC-310 with cap length) Inflow = 2.74 cfs @ 12.09 hrs, Volume= 0.205 of Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.12'L=14.7 cf Outflow = 2.76 cfs @ 12.09 hrs, Volume= 0.185 af, Atten=0%, Lag=0.5 min Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap Discarded = 0.03 cfs @ 9.54 hrs, Volume= 0.055 of Primary = 2.73 cfs @ 12.09 hrs, Volume= 0.130 of 34.0"Wide+6.0"Spacing=40.0"C-C Row Spacing Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs 7 Chambers/Row x 7.12'Long+0.60'Cap Length x 2=51.04'Row Length+12.0"End Stone x 2=53.04' Peak Elev=10.48'@ 12.09 hrs Surf.Area=1,153 sf Storage=1,468 cf Base Length Plug-Flow detention time=133.8 min calculated for 0.185 of(90%of inflow) 6 Rows x 34.0"Wide+6.0"Spacing x 5+12.0"Side Stone x 2=21.50'Base Width Center-of-Mass det.time=85.6 min(870.9-785.3) 6.0"Base+16.0"Chamber Height+6.0"Cover=2.33'Field Height Volume Invert Avail.Storage Storage Description 42 Chambers x 14.7 cf=619.2 cf Chamber Storage #1A 7.50' 817 cf 21.50'W x 53.041 x 2.33'H Field A 2,661 cf Overall-619 cf Embedded=2,042 cf x 40.0%Voids 2,660.8 cf Field-619.2 cf Chambers=2,041.7 cf Stone x 40.0%Voids=816.7 cf Stone Storage #2A 8.00' 619 cf ADS_StormTech SC-310+Capx 42 Inside#1 Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.121=14.7 cf Chamber Storage+Stone Storage=1,435.8 cf=0.033 of Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap Overall Storage Efficiency=54.0% 6 Rows of 7 Chambers Overall System Size=53.04'x 21.50'x 2.33' #3 7.92' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder #4 11.50' 1,104 cf Custom Staqe Data(PrismaticListed below(Recalc) 42 Chambers 2,583 cf Total Available Storage 98.5 cy Field Storage Group A created with Chamber Wizard 75.6 cy Stone Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 11.50 4 0 0 12.00 4,410 1,104 1,104 Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=23.0' CPP,projecting,no headwall, Ke=0.900 Inlet/Outlet Invert=4.00'/3.90' S=0.0043'/' Cc=0.900 n=0.013 Corrugated PE,smooth interior, Flow Area=1.23 sf #2 Device 1 10.10' 4.0'long x 0.5'breadth Broad-Crested Rectangular Weir Head(feet) 0.20 0.40 0.60 0.80 1.00 Coef.(English) 2.80 2.92 3.08 3.30 3.32 #3 Discarded 7.50' 1.020 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.03 cfs @ 9.54 hrs HW=7.92' (Free Discharge) t3=Exfiltration(Exfiltration Controls 0.03 cfs) MPrimary OutFlow Max=2.69 cfs @ 12.09 hrs HW=10.48' (Free Discharge) t1=Culvert(Passes 2.69 cfs of 11.28 cfs potential flow) t2=13road-Crested Rectangular Weir(Weir Controls 2.69 cfs @ 1.78 fps) I Z21 Z21 Z21 M201051_Post_Rev1 Type Ill 24-hr 2-YR Rainfall=3.20" M201051_Post_Rev1 Type 111 24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 13 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 14 Pond 1 P: Infiltration System#1 Summary for Pond 2P:Infiltration System#2 Hydrograph 4- 1 1 4- 1 4--14 �14 1 1 4- 1 4--1 4 k-1 4 1 4- 1� Inflow Area= 1 ac, 94.37%Impervious, Inflow Depth= 2.77" for 2-YR event � Min6ow Inflow = 3.66 66 c cfs @ 12.08 hrs, Volume= 0.282 of o�reow Outflow = 3.66 cfs @ 12.08 hrs, Volume= 0.262 af, Atten=0%, Lag=0.0 min ■Discarded nfl r .99 ■Primary Discarded = 0.03 cfs 7.22 hrs, Volume= 0.058 of 3� 1 P`pN g�- d5�i �' I I I I I' qa�pley7101_481 Primary = 3.63 cfs @ 12.08 hrs, Volume= 0.203 of i 1 6-40 C-f Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs Peak Elev=8.45'@ 12.08 hrs Surf.Area=1,153 sf Storage=1,471 cf IIIIIIII I IIIIIIIIIIIIIIIII 2/ Plug-Flow detention time=106.6 min calculated for 0.262 of(93%of inflow) Center-of-Mass det.time=68.0 min(839.1-771.1) Volume Invert AvaiLStorage Storage Description LL #1A 5.50, 817 cf 21.50'W x 53.041 x 2.33'H Field A 1_ 2,661 cf Overall-619 cf Embedded=2,042 cf x 40.0%Voids #2A 6.00' 619 cf ADS_StormTech SC-310+Capx 42 Inside#1 Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.12'L=14.7 cf Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap 6 Rows of 7 Chambers o #3 5.67' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder 0 1 2 3 a 5 6 7 6 9 10 11 1213 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 #4 9.00, 10,792 cf Custom Staqe Data(PrismaticListed below(Recalc) Time(hours) 12,272 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 9.00 4 0 0 10.00 21,580 10,792 10,792 Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=10.0' CPP,projecting,no headwall, Ke=0.900 Inlet/Outlet Invert=4.00'/3.90' S=0.0100'/' Cc=0.900 n=0.013 Corrugated PE,smooth interior, Flow Area=1.23 sf #2 Device 1 8.00' 4.0'long x 0.5'breadth Broad-Crested Rectangular Weir Head(feet) 0.20 0.40 0.60 0.80 1.00 Coef.(English) 2.80 2.92 3.08 3.30 3.32 #3 Discarded 5.50' 1.020 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.03 cfs @ 7.22 hrs HW=5.67' (Free Discharge) t3=Exfiltration(Exfiltration Controls 0.03 cfs) Primary OutFlow Max=3.61 cfs @ 12.08 hrs HW=8.45' (Free Discharge) t1=Culvert(Passes 3.61 cfs of 9.13 cfs potential flow) t2=Broad-Crested Rectangular Weir(Weir Controls 3.61 cfs @ 1.99 fps) M201051_Post_Rev1 Type 111 24-hr 2-YR Rainfall=3.20" M201051_Post_Rev1 Type 111 24-hr 2-YR Rainfall=3.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD®10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 15 HvdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Facie 16 Pond 2P:Infiltration System#2-Chamber Wizard Field A Pond 2P: Infiltration System#2 Hydrograph Chamber Model=ADS_StormTechSC-310+Cap(ADS StormTech®SC-310 with cap length) + —I + I + I—I + I--d +1+ 1 1-1 + I+ - Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.121=14.7 cf i ■inflow Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overly �" n •ouaow p 4r Infipw r 1r"=i.??� :Pri aryed 34.0"Wide+6.0"Spacing=40.0"C-C Row Spacing 1 1 �Iep��*Y-7 44 7 Chambers/Row x 7.12'Long+0.60'Cap Length x 2=51.04'Row Length+12.0"End Stone x 2=53.04' 1 1 1 $Wrago=0 64170 IC# Base Length 3— 9 6 Rows x 34.0"Wide+6.0"Spacing x 5+12.0"Side Stone x 2=21.50'Base Width 6.0"Base+16.0"Chamber Height+6.0"Cover=2.33'Field Height 42 Chambers x 14.7 cf=619.2 cf Chamber Storage o 2, - 2,660.8 cf Field-619.2 cf Chambers=2,041.7 cf Stone x 40.0%Voids=816.7 cf Stone Storage i 1� Chamber Storage+Stone Storage=1,435.8 cf=0.033 of Overall Storage Efficiency=54.0% Overall System Size=53.04'x 21.50'x 2.33' 0 42 Chambers o 1 z a a 5 6 7 8 9 10 11 12 13 4 15 16817 18 19 20 21 22 23 24 A26 27 28 29 30 98.5 cy Field 75.6 cy Stone �Z21 Z21 Z210 :2,�� M201051_Post_Rev1 Type 11124-hr 2-YR Rainfall=3.20" M201051_Post_Rev1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 17 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 18 Summary for Link DP-1: Time span=0.00-30.00 hrs,dt=0.02 hrs,1501 points Runoff by SCS TR-20 method,UH=SCS,Weighted-CN Inflow Area= 2.217 ac, 90.97%Impervious, Inflow Depth= 1.80" for 2-YR event Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Inflow = 6.30 cfs @ 12.09 hrs, Volume= 0.333 of Primary = 6.30 cfs @ 12.09 hrs, Volume= 0.333 af, Atten=0%, Lag=0.0 min SubcatchmentPR-1:Project Area#1 Runoff Area=29,830 sf 80.84%Impervious Runoff Depth=3.89" Tc=6.0 min CN=91 Runoff=2.99 cfs 0.222 of Primary outflow=Inflow,Time Span=0.00-30.00 hrs,dt=0.02 hrs SubcatchmentPR-1a:Ex.Bldg Area Runoff Area=13,459 sf 100.00%Impervious Runoff Depth=4.66" Link DP-1: Tc=6.0 min CN=98 Runoff=1.48 cfs 0.120 of Hydrograph SubcatchmentPR-2:Project Area#2 Runoff Area=33,326sf 90.99%Impervious Runoff Depth=4.32" -r 1-1-1 -r 1-1 T I I rt l-1-1 1 Tc=6.0 min CN=95 Runoff=3.56 cfs 0.275 of // ❑Inflow 7- eaoe" ��!h °Primary SubcatchmentPR-2a:Ex Bldg Area Runoff Area=19,957 sf 100.00%Impervious Runoff Depth=4.66" a e. MftPW iAM99-F-I�Ir 97 41r4 Tc=6.0 min CN=98 Runoff=2.19 cfs 0.178 of s% - -L I L I- L I L 1 1 -L 1 - I-t i- Pond 1 P:Infiltration System#1 Peak EIev=10.61' Storage=1,470 cf Inflow=4.46 cfs 0.342 of 5/ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Discarded=0.03 cfs 0.059 of Primary=4.44 cfs 0.262 of Outflow=4.46 cfs 0.321 of /-Irt fi fi rt I r-I-I t-1-1 fi t 1 T 1 rt r-I rt fi Pond 2P:Infiltration System#2 Peak EIev=8.60' Storage=1,473 cf Inflow=5.75 cfs 0.453 of a 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Discarded=0.03 cfs 0.062 of Primary=5.72 cfs 0.371 of Oufflow=5.75 cfs 0.433 of o Link DP-1: Inflow=10.16 cfs 0.634 of u 3 - - L - - Primary=10.16 cfs 0.634 of 2 / Total Runoff Area=2.217 ac Runoff Volume=0.795 of Average Runoff Depth=4.30" i-Irt fi -I t -Irt -Irt rt 9.03%Pervious=0.200 ac 90.97%Impervious=2.017 ac ,-' illilil ilil lillili o :..,�../../...i.,.,....,... ....,. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Post_Rev1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 19 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 20 Summary for Subcatchment PR-1:Project Area#1 Summary for Subcatchment PR-1 a:Ex.Bldg Area Runoff = 2.99 cfs @ 12.08 hrs, Volume= 0.222 af, Depth= 3.89" Runoff = 1.48 cfs @ 12.08 hrs, Volume= 0.120 af, Depth= 4.66" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 10-YR Rainfall=4.90" Type III 24-hr 10-YR Rainfall=4.90" Area(sf) CN Description Area(sf) CN Description 5,716 61 >75%Grass cover,Good,HSG B 13,459 98 Roofs,HSG B 24,114 98 Paved parkinq,HSG B 13,459 100.00%Impervious Area 29,830 91 Weighted Average 5,716 19.16%Pervious Area Tc Length Slope Velocity Capacity Description 24,114 80.84%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment PR-1 a: Ex.Bldg Area 6.0 Direct Entry,AB Hydrograph Subcatchment PR-1: Project Area#1 i l l l R��off Hydrograph i I I I 1 1 (Type III 247hr 1 1 -4 -- 1-1 + 1-1 4 4- 1— ■Rug 11 Q-YR Relirlfa117-4.9,0" 3- 1 1 1 1 1 1Type,III�47hf I I I I I1 R1u ingfflAyrear-113,1459I Sf I 11Q-YR F-all 4.9,0'i ,� 1 1 i I IU6-QfF1�11u10090-I 2"f- I IRlungfflAyrpa�29,18301sf I I I II I Runoff Depthr-4.66" 2_ _1 RuWOffiVpllugnO�II-R221 af- LL I I I I II I I I 1 TiI min 11 Runoff Depthr-3.891' 11 1 DN=98 1 1 1 1 1 1 1 TIc�6101 min 11 1 I I I _ DN=191_ 11 1 1 I I I I I I I I I I I I I II I I I I I I I o 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) o 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Post_Rev1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 21 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 22 Summary for Subcatchment PR-2:Project Area#2 Summary for Subcatchment PR-2a:Ex Bldg Area Runoff = 3.56 cfs @ 12.08 hrs, Volume= 0.275 af, Depth= 4.32" Runoff = 2.19 cfs @ 12.08 hrs, Volume= 0.178 af, Depth= 4.66" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 10-YR Rainfall=4.90" Type III 24-hr 10-YR Rainfall=4.90" Area(sf) CN Description Area(sf) CN Description 3,002 61 >75%Grass cover,Good,HSG B 19,957 98 Roofs,HSG B 30,324 98 Paved parkinq,HSG B 19,957 100.00%Impervious Area 33,326 95 Weighted Average 3,002 9.01%Pervious Area Tc Length Slope Velocity Capacity Description 30,324 90.99%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment PR-2a: Ex Bldg Area 6.0 Direct Entry,AB Hydrograph Subcatchment PR-2: Project Area#2 i 1 1 1 1 1 1 1 1 1 1 1 1 1 R��off Hydrograph 219N' I I I I I I I I I I I I e 11I I I I I I I I I I I I I I I I I I I I I I I —I� + II + �I+ + + +I+ + +I � + I T lyl� AI 24�h r— n= I I I I I I I I I I I I I I ■Rug 2/ I I I I I I I I I I I I I I 11 9-YR.li2airlfa117-4.90" I I I I I I I I Type,III�41hr I I I I I I I I I I 1 1 1 1 I RIu 1ngfflAyrga7-119,19571 Sf 3'-1-1 T I 1 T F 1-1 T I - T I-1 T "-YRRginfa+l:�4.9i81 I I I I I I I I I I I I I Runoff1Vp11ume:90.11781 of I I I I I I I I I I I I I IRlungfflAyrga:F313,13?61Sf I I I I I I I I I I 1 1 1 1 1 1 Runoff LDepthr-4.667 1 1 1 RumffIVol1urne:90-2751af + -I + 4- + -I + -I + 1-ITe 6Arriin- 2-� — fi t-1 rt r 1-1 1 1 -Runoff DepthF4.32ti'- CN=98 LL 1 I I 1 1 1 TIc:;6L01 min 1 1 CN=95 IIIIIIIIII I I I o 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 - 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Post_Rev1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 23 HvdroCADO 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 24 Summary for Pond 1 P:Infiltration System#1 Pond 1 P:Infiltration System#1 -Chamber Wizard Field A Inflow Area= 0.994 ac, 86.80%Impervious, Inflow Depth= 4.13" for 10-YR event Chamber Model=ADS_StormTechSC-310+Cap(ADS StormTech@SC-310 with cap length) Inflow = 4.46 cfs @ 12.08 hrs, Volume= 0.342 of Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.12'L=14.7 cf Outflow = 4.46 cfs @ 12.08 hrs, Volume= 0.321 af, Atten=0%, Lag=0.0 min Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap Discarded = 0.03 cfs @ 7.88 hrs, Volume= 0.059 of Primary = 4.44 cfs @ 12.08 hrs, Volume= 0.262 of 34.0"Wide+6.0"Spacing=40.0"C-C Row Spacing Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs 7 Chambers/Row x 7.12'Long+0.60'Cap Length x 2=51.04'Row Length+12.0"End Stone x 2=53.04' Peak Elev=10.61'@ 12.08 hrs Surf.Area=1,153 sf Storage=1,470 cf Base Length Plug-Flow detention time=90.1 min calculated for 0.321 of(94%of inflow) 6 Rows x 34.0"Wide+6.0"Spacing x 5+12.0"Side Stone x 2=21.50'Base Width Center-of-Mass det.time=57.4 min(831.2-773.8) 6.0"Base+16.0"Chamber Height+6.0"Cover=2.33'Field Height Volume Invert Avail.Storage Storage Description 42 Chambers x 14.7 cf=619.2 cf Chamber Storage #1A 7.50' 817 cf 21.50'W x 53.041 x 2.33'H Field A 2,661 cf Overall-619 cf Embedded=2,042 cf x 40.0%Voids 2,660.8 cf Field-619.2 cf Chambers=2,041.7 cf Stone x 40.0%Voids=816.7 cf Stone Storage #2A 8.00' 619 cf ADS_StormTech SC-310+Capx 42 Inside#1 Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.121=14.7 cf Chamber Storage+Stone Storage=1,435.8 cf=0.033 of Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap Overall Storage Efficiency=54.0% 6 Rows of 7 Chambers Overall System Size=53.04'x 21.50'x 2.33' #3 7.92' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder #4 11.50, 1,104 cf Custom Staqe Data(PrismaticListed below(Recalc) 42 Chambers 2,583 cf Total Available Storage 98.5 cy Field Storage Group A created with Chamber Wizard 75.6 cy Stone Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 11.50 4 0 0 12.00 4,410 1,104 1,104 Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=23.0' CPP,projecting,no headwall, Ke=0.900 Inlet/Outlet Invert=4.00'/3.90' S=0.0043'/' Cc=0.900 n=0.013 Corrugated PE,smooth interior, Flow Area=1.23 sf #2 Device 1 10.10' 4.0'long x 0.5'breadth Broad-Crested Rectangular Weir Head(feet) 0.20 0.40 0.60 0.80 1.00 Coef.(English) 2.80 2.92 3.08 3.30 3.32 #3 Discarded 7.50' 1.020 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.03 cfs @ 7.88 hrs HW=7.92' (Free Discharge) t3=Exfiltration(Exfiltration Controls 0.03 cfs) MPrimary OutFlow Max=4.41 cfs @ 12.08 hrs HW=10.61' (Free Discharge) t1=Culvert(Passes 4.41 cfs of 11.41 cfs potential flow) t2=13road-Crested Rectangular Weir(Weir Controls 4.41 cfs @ 2.15 fps) I Z21 Z21 Z21 M201051_Post_Rev1 Type 11124-hr 10-YR Rainfall=4.90" M201051_Post_Rev1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 25 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 26 Pond 1 P: Infiltration System#1 Summary for Pond 2P:Infiltration System#2 Hydrograph Inflow Area= 1.223 ac, 94.37%Impervious, Inflow Depth= 4.45" for 10-YR event ■in ow Inflow = 5.75 cfs @ 12.08 hrs, Volume= 0.453 of b°a yI�/ eI aI •o�reow Outflow = 5.75 cfs @ 12.08 hrs, Volume= 0.433 af, Atten=0%, Lag=0.0 min a 1 1' T-1 - oiarded @ s- _ t -1 fi �Yj t 1_I r .�9 ■Primary Discarded = 0.03 cfs 5.00 hrs, Volume= 0.062 of i 1 R�a���eNr��h��sl Primary = 5.72 cfs @ 12.08 hrs, Volume= 0.371 of 4� - -I _k 4 1-1 I�SxP4a9ip� P1 A7Q Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs Peak Elev=8.60'@ 12.08 hrs Surf.Area=1,153 sf Storage=1,473 cf � I II I I IIII IIIIIIIIIIIII - Plug-Flow detention time=74.9 min calculated for 0.433 of(95%of inflow) Center-of-Mass det.time=48.8 min(809.6-760.8) � IIIIIIIIIIIIIIIII LL 2i _I I_I I_I I_I I_I _ Volume Invert Avail.Storage Storaqe Description #1A 5.50, 817 cf 21.50'W x 53.041 x 2.33'H Field A 2,661 cf Overall-619 cf Embedded=2,042 cf x 40.0%Voids #2A 6.00' 619 cf ADS_StormTech SC-310+Capx 42 Inside#1 1i I Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.12'L=14.7 cf 03 Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap 6 Rows of 7 Chambers 0 . . . ... #3 5.67' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder 0 1 2 3 a 5 6 7 8 9 1011 1213 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 #4 9.00, 10,792 cf Custom Staqe Data(PrismaticListed below(Recalc) Time(hours) 12,272 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 9.00 4 0 0 10.00 21,580 10,792 10,792 Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=10.0' CPP,projecting,no headwall, Ke=0.900 Inlet/Outlet Invert=4.00'/3.90' S=0.0100'I' Cc=0.900 n=0.013 Corrugated PE,smooth interior, Flow Area=1.23 sf #2 Device 1 8.00' 4.0'long x 0.5'breadth Broad-Crested Rectangular Weir Head(feet) 0.20 0.40 0.60 0.80 1.00 Coef.(English) 2.80 2.92 3.08 3.30 3.32 #3 Discarded 5.50' 1.020 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.03 cfs @ 5.00 hrs HW=5.67' (Free Discharge) t3=Exfiltration(Exfiltration Controls 0.03 cfs) Primary OutFlow Max=5.69 cfs @ 12.08 hrs HW=8.60' (Free Discharge) t1=Culvert(Passes 5.69 cfs of 9.30 cfs potential flow) t2=Broad-Crested Rectangular Weir(Weir Controls 5.69 cfs @ 2.38 fps) M201051_Post_Rev1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Post_Rev1 Type III 24-hr 10-YR Rainfall=4.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD®10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Facie 27 HvdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 28 Pond 2P:Infiltration System#2-Chamber Wizard Field A Pond 2P: Infiltration System#2 Hydrograph Chamber Model=ADS_StormTechSC-310+Cap(ADS StormTech®SC-310 with cap length) Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.121=14.7 cf ■inflow Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap •outflow 1 1 fn1f� "�r�� �•�� �� - :Pri aryed 34.0"Wide+6.0"Spacing=40.0"C-C Row Spacing 6 i 51 11 1 1 1 1 1 1Plef i 7 Chambers/Row x 7.12'Long+0.60'Cap Length x 2=51.04'Row Length+12.0"End Stone x 2=53.04' 6 i —1 T 1 1 T 1 T T 1 1 T 17 Wra9v=0 6617-0 IPf - Base Length 6 Rows x 34.0"Wide+6.0"Spacing x 5+12.0"Side Stone x 2=21.50'Base Width 4i — — — — — — — — — — — - 6.0"Base+16.0"Chamber Height+6.0"Cover=2.33'Field Height i - 42 Chambers x 14.7 cf=619.2 cf Chamber Storage o 3% LL � ( IIIIIII IIIIIIIIIIIIIIII 2,660.8 cf Field-619.2 cf Chambers=2,041.7 cf Stone x 40.0%Voids=816.7 cf Stone Storage 2 —I T 1-1 T 1-1 r I rt —1 T 1—I i Chamber Storage+Stone Storage=1,435.8 cf=0.033 of i ' IIIIIII ii ii i I iii Overall Storage Efficiency=54.0% 1 ii Overall System Size=53.04'x 21.50'x 2.33' "h 42 Chambers 0 1 z a a5 6 7 8 9 1011 1213 14 1516817 18 19 20 21 22 23 24 25 26 27 28 29 30 Time 98.5 cy Field 75.6 cy Stone �Z21 Z21 Z210 :2,�� M201051_Post_Rev1 Type/1/24-hr 10-YR Rainfall=4.90" M201051_Post_Rev1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 29 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 30 Summary for Link DP-1: Time span=0.00-30.00 hrs,dt=0.02 hrs,1501 points Runoff by SCS TR-20 method,UH=SCS,Weighted-CN Inflow Area= 2.217 ac, 90.97%Impervious, Inflow Depth= 3.43" for 10-YR event Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Inflow = 10.16 cfs @ 12.08 hrs, Volume= 0.634 of Primary = 10.16 cfs @ 12.08 hrs, Volume= 0.634 af, Atten=0%, Lag=0.0 min SubcatchmentPR-1:Project Area#1 Runoff Area=29,830 sf 80.84%Impervious Runoff Depth=5.15" Tc=6.0 min CN=91 Runoff=3.90 cfs 0.294 of Primary outflow=Inflow,Time Span=0.00-30.00 hrs,dt=0.02 hrs SubcatchmentPR-1a:Ex.Bldg Area Runoff Area=13,459 sf 100.00%Impervious Runoff Depth=5.96" Link DP-1: Tc=6.0 min CN=98 Runoff=1.88 cfs 0.154 of Hydrograph SubcatchmentPR-2:Project Area#2 Runoff Area=33,326sf 90.99%Impervious Runoff Depth=5.61" /-I 1 1 1 1 1 1- 1 1 1 1 -4 �-1 4- 1 1 Tc=6.0 min CN=95 Runoff=4.56 cfs 0.358 of ❑Inflow 11/ z-1 J L I J 1 I -L +o,e"r. L I J L 1-1 1 1-1 1 L I J L 1-1 -L 11 P"Mary SubcatchmentPR-2a:Ex BldgArea Runoff Area=19,957 sf 100.00%Impervious Runoff Depth=5.96" 10% -I J L I J 1 _ 1 6 L I J I"f-'PN Argue�2�217 p4 Tc=6.0 min CN=98 Runoff=2.78 cfs 0.228 of 9. _ J LIJ L - 1 L I J L 1-1 1 1-1 1 L I J L 1-1 1 Pond 1 P:Infiltration System#1 Peak EIev=10.70' Storage=1,471 cf Inflow=5.77 cfs 0.448 of Discarded=0.03 cfs 0.061 of Primary=5.75 cfs 0.366 of Outflow=5.77 cfs 0.427 of Pond 2P:Infiltration System#2 Peak EIev=8.69' Storage=1,474 cf Inflow=7.34 cfs 0.585 of Discarded=0.03 cfs 0.063 of Primary=7.31 cfs 0.502 of Oufflow=7.34 cfs 0.565 of a _IIIIIIIII IIIIIIIIIIIIIIII s 6i - - - - _ - - - - - - - - - - - - Link DP-1: Inflow=13.05 cfs 0.868 of LL j I I I I I I I I I I I I I I I I I I I I I I I I I Primary=13.05 cfs 0.868 of 4 -( IIIIIII IIIIIIIIIIIIII 3j - - - _ - - - - - - - - - - - Total Runoff Area=2.217 ac Runoff Volume=1.033 of Average Runoff Depth=5.59" 9.03%Pervious=0.200 ac 90.97%Impervious=2.017 ac 2� - - - - - - - - - - - - - - - - - 1=' 0 i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type/1/24-hr 25-YR Rainfall=6.20" M201051_Post_Rev1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 31 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 32 Summary for Subcatchment PR-1:Project Area#1 Summary for Subcatchment PRAa:Ex.Bldg Area Runoff = 3.90 cfs @ 12.08 hrs, Volume= 0.294 af, Depth= 5.15" Runoff = 1.88 cfs @ 12.08 hrs, Volume= 0.154 af, Depth= 5.96" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 25-YR Rainfall=6.20" Type III 24-hr 25-YR Rainfall=6.20" Area(sf) CN Description Area(sf) CN Description 5,716 61 >75%Grass cover,Good,HSG B 13,459 98 Roofs,HSG B 24,114 98 Paved parkinq,HSG B 13,459 100.00%Impervious Area 29,830 91 Weighted Average 5,716 19.16%Pervious Area Tc Length Slope Velocity Capacity Description 24,114 80.84%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment PRAa: Ex.Bldg Area 6.0 Direct Entry,AB Hydrograph Subcatchment PR-1: Project Area#1 �_ _ _III l II oR"off z� aab= Hydrograph I I I illllllllll II ' I . I . IIIII IIII Type III 24 7hr 4/—1-1 T- 1-1 rt F 11-1T 39on= I -f r 1-1 T I—I 1 7 1— .anon I I I I 1 1 1 12�-YR Rzlirlfall7-6.2O" 1 1 I I I I 1Type,III�41hr I I I I I 1 RIu ingfflAyrgar-113,14591 sf 1 1 I 12�-XR Reiigfall: f§.�Ori I I I 1 1 1 IRunofflVollume=0.11541af 3� i T -I 1-RumgfFAlr-Qa-:M,830-i sf- - - - -1 -1 L 1-1 L -L L 1-1 -L -Runoff-Deipthr5.96"- I I I I I I I I I I I I I IRunoffiWIRiMe:90.2941af I I I I I I I I I I ITc=6LO min 1 1 1 1 1 I I 1 I_iRunoff lDelpthr-5.1157_ 1 1 1 1 1 1 CN=198 LL 2-� 1 1 1 1 1 1 1 1 1 1 1 1 1 1 _ 1 1 TIC oUl min I I I I I I I I I I I I I CN=191 _1-1 L 11 1 LIJ L 111 L I- 1� I I I I I I I I I I I I 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 - 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type/1/24-hr 25-YR Rainfall=6.20" M201051_Post_Rev1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 33 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 34 Summary for Subcatchment PR-2:Project Area#2 Summary for Subcatchment PII Ex Bldg Area Runoff = 4.56 cfs @ 12.08 hrs, Volume= 0.358 af, Depth= 5.61" Runoff = 2.78 cfs @ 12.08 hrs, Volume= 0.228 af, Depth= 5.96" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 25-YR Rainfall=6.20" Type III 24-hr 25-YR Rainfall=6.20" Area(sf) CN Description Area(sf) CN Description 3,002 61 >75%Grass cover,Good,HSG B 19,957 98 Roofs,HSG B 30,324 98 Paved parkinq,HSG B 19,957 100.00%Impervious Area 33,326 95 Weighted Average 3,002 9.01%Pervious Area Tc Length Slope Velocity Capacity Description 30,324 90.99%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment PR-2a: Ex Bldg Area 6.0 Direct Entry,AB Hydrograph Subcatchment PR-2: Project Area#2 1—1 1 L _1 -1 L 1_I -L — — L Hydrograph Type II 24 hr - —I L —I + —I — L —I + —I I— I I I I I I I Dip � 7 5/ �= I ■Runoff I I I I I I 12�-YR R.Jinfa117-6.1O" 1 I I_I I I Type,III�47hr_ I � �I—I -AunQfflA'near-119,1957�Sf 4� 1 1 1 1 1 1 1 1 12�-X IR IZair�fMI:�Q-ZOri 2 I I I IRunof iVolwe�0.2281af 1 1 1 1RlumgfflArea�313,13�61s _ I . I I 11 I I I I Runoff Depth7-5.96" 3�—1� 7 1-1 7 F I I—i RunQffiV�oIutlne�@-1358Taf LL 1 TcT6LO min I I I Runoff Depthr-51.617r 1- 4 L I-1 1-1 -4 4- 1-1 —1-1 L 1 1 1 L I� L L I I L I I A L I I Tc:;-&Olmin- 2� I I I I I I I I I CN=95 IIIIIIII I I ( IIIIIIII I IIIIII I I ( IIIIIIII I I 11111111 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type///24-hr 25-YR Rainfall=6.20" M201051_Post_Rev1 Type Ill 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 35 HvdroCADO 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 36 Summary for Pond 1 P:Infiltration System#1 Pond 1 P:Infiltration System#1 -Chamber Wizard Field A Inflow Area= 0.994 ac, 86.80%Impervious, Inflow Depth= 5.40" for 25-YR event Chamber Model=ADS_StormTechSC-310+Cap(ADS StormTech@SC-310 with cap length) Inflow = 5.77 cfs @ 12.08 hrs, Volume= 0.448 of Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.12'L=14.7 cf Outflow = 5.77 cfs @ 12.08 hrs, Volume= 0.427 af, Atten=0%, Lag=0.0 min Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap Discarded = 0.03 cfs @ 6.78 hrs, Volume= 0.061 of Primary = 5.75 cfs @ 12.08 hrs, Volume= 0.366 of 34.0"Wide+6.0"Spacing=40.0"C-C Row Spacing Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs 7 Chambers/Row x 7.12'Long+0.60'Cap Length x 2=51.04'Row Length+12.0"End Stone x 2=53.04' Peak Elev=10.70'@ 12.08 hrs Surf.Area=1,153 sf Storage=1,471 cf Base Length Plug-Flow detention time=73.7 min calculated for 0.427 of(95%of inflow) 6 Rows x 34.0"Wide+6.0"Spacing x 5+12.0"Side Stone x 2=21.50'Base Width Center-of-Mass det.time=47.5 min(815.4-767.9) 6.0"Base+16.0"Chamber Height+6.0"Cover=2.33'Field Height Volume Invert Avail.Storage Storage Description 42 Chambers x 14.7 cf=619.2 cf Chamber Storage #1A 7.50' 817 cf 21.50'W x 53.041 x 2.33'H Field A 2,661 cf Overall-619 cf Embedded=2,042 cf x 40.0%Voids 2,660.8 cf Field-619.2 cf Chambers=2,041.7 cf Stone x 40.0%Voids=816.7 cf Stone Storage #2A 8.00' 619 cf ADS_StormTech SC-310+Capx 42 Inside#1 Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.121=14.7 cf Chamber Storage+Stone Storage=1,435.8 cf=0.033 of Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap Overall Storage Efficiency=54.0% 6 Rows of 7 Chambers Overall System Size=53.04'x 21.50'x 2.33' #3 7.92' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder #4 11.50' 1,104 cf Custom Staqe Data(PrismaticListed below(Recalc) 42 Chambers 2,583 cf Total Available Storage 98.5 cy Field Storage Group A created with Chamber Wizard 75.6 cy Stone Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 11.50 4 0 0 12.00 4,410 1,104 1,104 Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=23.0' CPP,projecting,no headwall, Ke=0.900 Inlet/Outlet Invert=4.00'/3.90' S=0.0043'/' Cc=0.900 n=0.013 Corrugated PE,smooth interior, Flow Area=1.23 sf #2 Device 1 10.10' 4.0'long x 0.5'breadth Broad-Crested Rectangular Weir Head(feet) 0.20 0.40 0.60 0.80 1.00 Coef.(English) 2.80 2.92 3.08 3.30 3.32 #3 Discarded 7.50' 1.020 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.03 cfs @ 6.78 hrs HW=7.92' (Free Discharge) t3=Exfiltration(Exfiltration Controls 0.03 cfs) MPrimary OutFlow Max=5.71 cfs @ 12.08 hrs HW=10.70' (Free Discharge) t1=Culvert(Passes 5.71 cfs of 11.50 cfs potential flow) t2=13road-Crested Rectangular Weir(Weir Controls 5.71 cfs @ 2.38 fps) I Z21 Z21 Z21 M201051_Post_Rev1 Type Ill 24-hr 25-YR Rainfall=6.20" M201051_Post_Rev1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 37 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 38 Pond 1 P: Infiltration System#1 Summary for Pond 2P:Infiltration System#2 Hydrograph Inflow Area= 1.223 ac, 94.37%Impervious, Inflow Depth= 5.74" for 25-YR event ■in ow Inflow = 7.34 cfs @ 12.08 hrs, Volume= 0.585 of i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 D�reow Outflow = 7.34 cfs @ 12.08 hrs, Volume= 0.565 af, Atten=0%, Lag=0.0 min Ce ■Discarded L I� LI 1 I-I nfIl r .199 ■Primary Discarded = 0.03 cfs @ 3.92 hrs, Volume= 0.063 of _11 II B I PL�- �5 6/ 1 1 1 1 11 1 51" 1 1 1 1 1 1 1 Rqa�gleM71 Or701 Primary = 7.31 cfs @ 12.08 hrs, Volume= 0.502 of a l 47 Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs e/ -I rtI rt I� rt t I� Q� � b Peak Elev=8.69'@ 12.08 hrs Surf.Area=1,153 sf Storage=1,474 cf Plug-Flow detention time=62.1 min calculated for 0.565 of(96%of inflow) Center-of-Mass det.time=41.1 min(796.9-755.8) I� LI� L111_111� _ 3� Volume Invert Avail.Storage Storaqe Description LL i #1A 5.50, 817 cf 21.50'W x 53.041 x 2.33'H Field A 2,661 cf Overall-619 cf Embedded=2,042 cf x 40.0%Voids i #2A 6.00' 619 cf ADS_StormTech SC-310+Capx 42 Inside#1 Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.12'L=14.7 cf 1. Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap 003 6 Rows of 7 Chambers o (/r #3 5.67' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder 0 8 s 1011 1213 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 #4 9.00, 10,792 cf Custom Staqe Data(PrismaticListed below(Recalc) Time(hours) 12,272 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 9.00 4 0 0 10.00 21,580 10,792 10,792 Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=10.0' CPP,projecting,no headwall, Ke=0.900 Inlet/Outlet Invert=4.00'/3.90' S=0.0100'/' Cc=0.900 n=0.013 Corrugated PE,smooth interior, Flow Area=1.23 sf #2 Device 1 8.00' 4.0'long x 0.5'breadth Broad-Crested Rectangular Weir Head(feet) 0.20 0.40 0.60 0.80 1.00 Coef.(English) 2.80 2.92 3.08 3.30 3.32 #3 Discarded 5.50' 1.020 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.03 cfs @ 3.92 hrs HW=5.67' (Free Discharge) t3=Exfiltration(Exfiltration Controls 0.03 cfs) Primary OutFlow Max=7.27 cfs @ 12.08 hrs HW=8.69' (Free Discharge) t1=Culvert(Passes 7.27 cfs of 9.40 cfs potential flow) t2=Broad-Crested Rectangular Weir(Weir Controls 7.27 cfs @ 2.64 fps) M201051_Post_Rev1 Type/1/24-hr 25-YR Rainfall=6.20" M201051_Post_Rev1 Type 111 24-hr 25-YR Rainfall=6.20" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD®10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Facie 39 HvdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Paae 40 Pond 2P:Infiltration System#2-Chamber Wizard Field A Pond 2P: Infiltration System#2 Hydrograph Chamber Model=ADS_StormTechSC-310+Cap(ADS StormTech®SC-310 with cap length) 1 1 1 1 1+ 1 + 1 1 + 1 1-4 �1+ 1 + Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.12'L=14.7 cf / ■inflow Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overaa / _ I_I °" It _I ■°avow p i"I P`N I' r�� �2 �C ■P°aryed 34.0"Wide+6.0"Spacing=40.0"C-C Row Spacing / I I I I I 1 1 1 1 1 1 �1"� Ier7"9 ,, 7 Chambers/Row x 7.12'Long+0.60'Cap Length x 2=51.04'Row Length+12.0"End Stone x 2=53.04' / -1 + 1 1 + I� - 1 1 + 1-1$t��q0 b647-4 Ps Base Length 6- / / _I J 1_I J IJ J IJ L I J L 1 1 I_1 1 IJ _ 6 Rows x 34.0"Wide+6.0"Spacing x 5+12.0"Side Stone x 2=21.50'Base Width 6.0"Base+16.0"Chamber Height+6.0"Cover=2.33'Field Height 42 Chambers x 14.7 cf=619.2 cf Chamber Storage o a/ I t 1-1 t 1-1 2,660.8 cf Field-619.2 cf Chambers=2,041.7 cf Stone x 40.0%Voids=816.7 cf Stone Storage 2� / illllll Chamber Storage+Stone Storage=1,435.8 cf=0.033 of / Overall Storage Efficiency=54.0% 1� Overall System Size=53.04'x 21.50'x 2.33' o 42 Chambers o 1 2 3 a s s 7 8 9 10 11 12 l 67 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 98.5 cy Field 75.6 cy Stone M201051_Post_Rev1 Type///24-hr 25-YR Rainfall=6.20" M201051_Post_Rev1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 41 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 42 Summary for Link DP-1: Time span=0.00-30.00 hrs,dt=0.02 hrs,1501 points Runoff by SCS TR-20 method,UH=SCS,Weighted-CN Inflow Area= 2.217 ac, 90.97%Impervious, Inflow Depth= 4.70" for 25-YR event Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Inflow = 13.05 cfs @ 12.08 hrs, Volume= 0.868 of Primary = 13.05 cfs @ 12.08 hrs, Volume= 0.868 af, Atten=0%, Lag=0.0 min SubcatchmentPR-1:Project Area#1 Runoff Area=29,830 sf 80.84%Impervious Runoff Depth=7.81" Tc=6.0 min CN=91 Runoff=5.77 cfs 0.446 of Primary outflow=Inflow,Time Span=0.00-30.00 hrs,dt=0.02 hrs SubcatchmentPR-1a:Ex.Bldg Area Runoff Area=13,459 sf 100.00%Impervious Runoff Depth=8.66" Link DP-1: Tc=6.0 min CN=98 Runoff=2.70 cfs 0.223 of Hydrograph SubcatchmentPR-2:Project Area#2 Runoff Area=33,326sf 90.99%Impervious Runoff Depth=8.30" /-I 1 L I J L 1-1 1 L I -i L I J L 1-1 1 1-1 1 L I L 1-1 1 D inflow Tc=6.0 min CN=95 Runoff=6.61 cfs 0.529 of 14 -1-4 4-1 A + 1-1 4 +3os . 1-4 4- 1-1 � 1-11 4 �11-4 4- 1-1 D Primary SubcatchmentPR-2a:Ex BldgArea Runoff Area=19,957 sf 100.00%Impervious Runoff Depth=8.66" 13! i-I t t- 1-1 t t ao '"Tr� r2 1��� Tc=6.0 min CN=98 Runoff=4.00 cfs 0.331 of 12"" IIIIIIIII 11111111111111111 - - - - - - - - - - Pond 1 P:Infiltration System#1 Peak EIev=10.85' Storage=1,473 cf Inflow=8.47 cfs 0.669 of 11 / Discarded=0.03 cfs 0.063 of Primary=8.44 cfs 0.585 of Outflow=8.47 cfs 0.649 of -4 1--A 4- 1-1 4- 1-4 4- 1-1 + 1-1 4 1-4 4-- 1-1 + Pond 2P:Infiltration System#2 Peak EIev=9.10' Storage=1,577 cf Inflow=10.61 cfs 0.860 of a! i- t t l t l-I t r l t fi I-I t -Irt r l t fi 1-1 t Discarded=0.08 cfs 0.065 of Primary=9.86 cfs 0.774 of Oufflow=9.93 cfs 0.839 of Link DP-1: Inflow=18.28 cfs 1.359 of LL 6� Primary=18.28 cfs 1.359 of -4 1--A 4- 1-1 4- -1-4 4- 1-1 1-1 4 1-4 4-- 1-1 Total Runoff Area=2.217 ac Runoff Volume=1.529 of Average Runoff Depth=8.27" a% i-Irt 1-I-1 t 1-1 t I t fi t-1 t 1-1 rt r-I t 1- 1-1 t 9.03%Pervious=0.200 ac 90.97%Impervious=2.017 ac 2� i 1 0' ......%...(....f../..r.../..../.../... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type///24-hr 100-YR Rainfall=8.90" M201051_Post_Rev1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 43 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 44 Summary for Subcatchment PII Project Area#1 Summary for Subcatchment PR-1 a:Ex.Bldg Area Runoff = 5.77 cfs @ 12.08 hrs, Volume= 0.446 af, Depth= 7.81" Runoff = 2.70 cfs @ 12.08 hrs, Volume= 0.223 af, Depth= 8.66" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 100-YR Rainfall=8.90" Type III 24-hr 100-YR Rainfall=8.90" Area(sf) CN Description Area(sf) CN Description 5,716 61 >75%Grass cover,Good,HSG B 13,459 98 Roofs,HSG B 24,114 98 Paved parkinq,HSG B 13,459 100.00%Impervious Area 29,830 91 Weighted Average 5,716 19.16%Pervious Area Tc Length Slope Velocity Capacity Description 24,114 80.84%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment PR-1 a: Ex.Bldg Area 6.0 Direct Entry,AB Hydrograph Subcatchment PR-1: Project Area#1 3 -I -T L I—I I ❑R""off Hydrograph . I I i 11 I 1 1 I 1 I I I I I I I I I I I I I I I I I L 1 1 (Type III 247hr 6� 1-1 1 1 1-1 i s.n. L —� T L - L I-1 T 1-1 1 - ■Runoff 0-YR R-11 91117-8.9,0" I I I I I I I I I I I I I I I I I 1 1 (Type,III�47hr -1- t 1-1 t t 1-1 1 lne(fftArear-113,14591 Sf 5-- 1 1 1 1 1 1 1 1 1 1 1 1 1 1 111�Q 1R i ��� •�'Ir 2 1 1 1 1 1 1 1 1 1 1 OfflVQIiuMe�0.2231af 1 I I I IRungfflAlrea��9,18301sf I I I I I I I I I I Runoff Depth7-8.66" 4� 1 1 1 1 1 1 1 1 1 1 1 1 1 1RumfflVollume:90.1446W LL 1 1 I I I I I II I I I 1Tc=6L0 min -I _ 1 _' Runoff l�elpth�7�.81T_ 1�-1� fi t-1 t i-I 1 1 I -t i- 1-1 t I-I=198 LL 3� I I I I I I I I I I ' I I I I I I 1 1 Two610i min 11 L 11 L LIJ L L _I L 111 L 1 11 I CN J91_ 2� IIIIIIIIII III - IIIIII 1�-1-4 � 1-14 �1� -k 14- 1-1 - LI 1 4 ' I! 6 III 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type///24-hr 100-YR Rainfall=8.90" M201051_Post_Rev1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 45 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 46 Summary for Subcatchment PR-2:Project Area#2 Summary for Subcatchment PR-2a:Ex Bldg Area Runoff = 6.61 cfs @ 12.08 hrs, Volume= 0.529 af, Depth= 8.30" Runoff = 4.00 cfs @ 12.08 hrs, Volume= 0.331 af, Depth= 8.66" Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Runoff by SCS TR-20 method,UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.02 hrs Type III 24-hr 100-YR Rainfall=8.90" Type III 24-hr 100-YR Rainfall=8.90" Area(sf) CN Description Area(sf) CN Description 3,002 61 >75%Grass cover,Good,HSG B 19,957 98 Roofs,HSG B 30,324 98 Paved parkinq,HSG B 19,957 100.00%Impervious Area 33,326 95 Weighted Average 3,002 9.01%Pervious Area Tc Length Slope Velocity Capacity Description 30,324 90.99%Impervious Area (min) (feet) (fUft) (ft/sec) (cfs) 6.0 Direct Entry, Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) Subcatchment PR-2a: Ex Bldg Area 6.0 Direct Entry,AB Hydrograph Subcatchment PR-2: Project Area#2 i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ■Runoff -I Hydrograph 4� A � I-1 4 1� � 4ont4 1-I + I-1 -4 1-I I i e 111IIII IIIIIIIIIIIIIIIIII IIIIIIII Type III 247hr 7� �.1I I I iI I I I I I I I I I ■Runoff 11109-YR 9.1infal17-8.90" - I -1 ! + - + 1-1 -4 �_ IT-yRe1I1I g47-hr 3_-1-1 r 1-1 -T r 1-1 T rt r 1-1 TRu InQffArear-119,1957TSf- e� 1 I I I I I I I I 1109-YR 9.110.111�:$.90 I I I I I I I I I I 1 1 I 1RunofflVollume:90.13311af 1 T 1-1 7 r 1 - F 1-1 TRunQ"rQa7-313,1396TSf- I I I I I I I I I 1 1 1 1 1 1 Runoff Delpthr-8.66" 1 1 1Runoff1VolluMe:90.15291af LL 2-' 1 1 1 1 1 1 1 1 1 1 I I 1 1 1 1 1 1 1 1 1TIC*6L0 min 4-� 1 1 1 1 1 1 1 1 1 Runoff De'pthr-8.307 CN=98 LL -I-A + II + I + - +1+ + II 4 + IITe*C01n11n 3 CN=95 2/ IIIIIIIIII IIII II II II II II II III IIIIII I ' ' IIIIIIIIIII I_I I_I I_I I_I I_I 1 °0 1 z s4 ee i s s 1oii 1'z �� 13 14 15 16 17 18 19 20 21 22 23 24 26 28 27 28 29 30 Time(hours) 0 - 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time(hours) M201051_Post_Rev1 Type///24-hr 100-YR Rainfall=8.90" M201051_Post_Rev1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 47 HvdroCADO 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 48 Summary for Pond 1 P:Infiltration System#1 Pond 1 P:Infiltration System#1 -Chamber Wizard Field A Inflow Area= 0.994 ac, 86.80%Impervious, Inflow Depth= 8.08" for 100-YR event Chamber Model=ADS_StormTechSC-310+Cap(ADS StormTech@SC-310 with cap length) Inflow = 8.47 cfs @ 12.08 hrs, Volume= 0.669 of Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.12'L=14.7 cf Outflow = 8.47 cfs @ 12.08 hrs, Volume= 0.649 af, Atten=0%, Lag=0.0 min Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap Discarded = 0.03 cfs @ 4.92 hrs, Volume= 0.063 of Primary = 8.44 cfs @ 12.08 hrs, Volume= 0.585 of 34.0"Wide+6.0"Spacing=40.0"C-C Row Spacing Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs 7 Chambers/Row x 7.12'Long+0.60'Cap Length x 2=51.04'Row Length+12.0"End Stone x 2=53.04' Peak Elev=10.85'@ 12.08 hrs Surf.Area=1,153 sf Storage=1,473 cf Base Length Plug-Flow detention time=54.9 min calculated for 0.649 of(97%of inflow) 6 Rows x 34.0"Wide+6.0"Spacing x 5+12.0"Side Stone x 2=21.50'Base Width Center-of-Mass det.time=36.1 min(795.9-759.8) 6.0"Base+16.0"Chamber Height+6.0"Cover=2.33'Field Height Volume Invert Avail.Storage Storage Description 42 Chambers x 14.7 cf=619.2 cf Chamber Storage #1A 7.50' 817 cf 21.50'W x 53.041 x 2.33'H Field A 2,661 cf Overall-619 cf Embedded=2,042 cf x 40.0%Voids 2,660.8 cf Field-619.2 cf Chambers=2,041.7 cf Stone x 40.0%Voids=816.7 cf Stone Storage #2A 8.00' 619 cf ADS_StormTech SC-310+Capx 42 Inside#1 Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.121=14.7 cf Chamber Storage+Stone Storage=1,435.8 cf=0.033 of Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap Overall Storage Efficiency=54.0% 6 Rows of 7 Chambers Overall System Size=53.04'x 21.50'x 2.33' #3 7.92' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder #4 11.50' 1,104 cf Custom Staqe Data(PrismaticListed below(Recalc) 42 Chambers 2,583 cf Total Available Storage 98.5 cy Field Storage Group A created with Chamber Wizard 75.6 cy Stone Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 11.50 4 0 0 12.00 4,410 1,104 1,104 Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=23.0' CPP,projecting,no headwall, Ke=0.900 Inlet/Outlet Invert=4.00'/3.90' S=0.0043'/' Cc=0.900 n=0.013 Corrugated PE,smooth interior, Flow Area=1.23 sf #2 Device 1 10.10' 4.0'long x 0.5'breadth Broad-Crested Rectangular Weir Head(feet) 0.20 0.40 0.60 0.80 1.00 Coef.(English) 2.80 2.92 3.08 3.30 3.32 #3 Discarded 7.50' 1.020 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.03 cfs @ 4.92 hrs HW=7.92' (Free Discharge) t3=Exfiltration(Exfiltration Controls 0.03 cfs) MPrimary OutFlow Max=8.40 cfs @ 12.08 hrs HW=10.85' (Free Discharge) t1=Culvert(Passes 8.40 cfs of 11.64 cfs potential flow) t2=13road-Crested Rectangular Weir(Weir Controls 8.40 cfs @ 2.81 fps) I Z21 Z21 Z21 M201051_Post_Rev1 Type 11124-hr 100-YR Rainfall=8.90" M201051_Post_Rev1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 49 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Facie 50 Pond 1 P: Infiltration System#1 Summary for Pond 2P:Infiltration System#2 Hydrograph Inflow Area= 1.223 ac, 94.37%Impervious, Inflow Depth= 8.43" for 100-YR event ■in ow Inflow = 10.61 cfs @ 12.08 hrs, Volume= 0.860 of / °°� I_I •D�reow Outflow = 9.93 cfs @ 12.12 hrs, Volume= 0.839 af, Atten=6%, Lag=2.2 min / - - - - - - es - ■Discarded 99 ■Primary Discarded = 0.08 cfs @ 12.11 hrs, Volume= 0.065 of el°� I I I I I'I"I�r��T�"I•`1�1 Primary = 9.86 cfs @ 12.12 hrs, Volume= 0.774 of e / I T 1 T 1-1 1 1 1 1%4pTagq=11 64 Cf Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.02 hrs 7;'- / Peak Elev=9.10'@ 12.11 hrs Surf.Area=3,214 sf Storage=1,577 cf / -1TI-I TIT 1 r1-1T1-1rITrIrt -1TIT f H t -I H Plug-Flow detention time=46.4 min calculated for 0.839 of(98%of inflow) -I + / Center-of-Mass det.time=31.5 min(780.6-749.1) LL 4 _I 1 1-I 1 IL] LI 1 IJ L J L 1 1 1-I 1 L] _ Volume Invert Avail.Storage Storage Description / #1A 5.50, 817 cf 21.50'W x 53.041 x 2.33'H Field A _I I I-I I-I I-I I-I -I 1-1 _ 2,661 cf Overall-619 cf Embedded=2,042 cf x 40.0%Voids #2A 6.00' 619 cf ADS_StormTech SC-310+Capx 42 Inside#1 / Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.12'L=14.7 cf 1� 003�g i Overall Size=34.0"W x 16.0"H x 7.56'L with 0.44'Overlap 6 Rows of 7 Chambers 04 ; #3 5.67' 44 cf 4.00'D x 3.50'H Vertical Cone/Cylinder 0 1 2 3 a 5 6 7 8 9 1011 1213 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 #4 9.00, 10,792 cf Custom Staqe Data(PrismaticListed below(Recalc) Time(hours) 12,272 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 9.00 4 0 0 10.00 21,580 10,792 10,792 Device Routinq Invert Outlet Devices #1 Primary 4.00' 15.0" Round Culvert L=10.0' CPP,projecting,no headwall, Ke=0.900 Inlet/Outlet Invert=4.00'/3.90' S=0.0100'/' Cc=0.900 n=0.013 Corrugated PE,smooth interior, Flow Area=1.23 sf #2 Device 1 8.00' 4.0'long x 0.5'breadth Broad-Crested Rectangular Weir Head(feet) 0.20 0.40 0.60 0.80 1.00 Coef.(English) 2.80 2.92 3.08 3.30 3.32 #3 Discarded 5.50' 1.020 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.07 cfs @ 12.11 hrs HW=9.09' (Free Discharge) t3=Exfiltration(Exfiltration Controls 0.07 cfs) Primary OutFlow Max=9.86 cfs @ 12.12 hrs HW=9.09' (Free Discharge) t1=Culvert(Inlet Controls 9.86 cfs @ 8.03 fps) t2=Broad-Crested Rectangular Weir(Passes 9.86 cfs of 15.16 cfs potential flow) M201051_Post_Rev1 Type///24-hr 100-YR Rainfall=8.90" M201051_Post_Rev1 Type 1/124-hr 100-YR Rainfall=8.90" Prepared by Bohler Engineering Printed 5/4/2021 Prepared by Bohler Engineering Printed 5/4/2021 HvdroCAD®10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Facie 51 HvdroCADO 10.00-19 s/n 08955 ©2016 HvdroCAD Software Solutions LLC Facie 52 Pond 2P:Infiltration System#2-Chamber Wizard Field A Pond 2P: Infiltration System#2 Hydrograph Chamber Model=ADS_StormTechSC-310+Cap(ADS StormTech®SC-310 with cap length) I I I I I I I I I I I I I I I I I Effective Size=28.9"W x 16.0"H=>2.07 sf x 7.121=14.7 cf — — — — — — — — — — — — — — — — — - IN inflow Overall Size=34.0"W x 16.0"H x 7.561 with 0.44'Overly i I_I °s° •°aeow p _ 1 1 19a° %I '1 P�'1�4rr� •�� - 'Pri e, 34.0"Wide+6.0"Spacing=40.0"C-C Row Spacing 1 I—I 1 I_I —1 ��� e"7-191 _ 10! � 7 Chambers/Row x 7.12'Long+0.60'Cap Length x 2=51.04'Row Length+12.0"End Stone x 2=53.04's _ -L 1-1 1 1-1 _L 1-1$tp a9 p_71557� Base 6 Rows 34.0"Wide+6.0"Spacing x 5+12.0"Side Stone x 2=21.50'Base Width 8i —1 -4 �1 4 1 1 4- 1--� 4-1- 1 4 �I - 6.0"Base+16.0"Chamber Height+6.0"Cover=2.33'Field Height 7- — —I t I + 1 - " - 42 Chambers x 14.7 cf=619.2 cf Chamber Storage ' 5� I T 1 1 7 1 T l I T 11 T I—T T—1 7 T I 2,660.8 cf Field-619.2 cf Chambers=2,041.7 cf Stone x 40.0%Voids=816.7 cf Stone Storage 4? i 3� / 111 1 111 1 11 11 Chamber Storage+Stone Storage=1,435.8 cf=0.033 of 2j � Overall Storage Efficiency=54.0% Overall System Size=53.04'x 21.50'x 2.33' 42 Chambers 0 1 2 3 4 5 6 7 8 9 1011 12 1314 �15 1�617 18 19 20 21 22 23 24 25 26 27 28 29 30 Tim98.5 cy Field 75.6 cy Stone �Z21 Z21 Z210 :2,�� M201051_Post ReA Type 11124-hr 100-YR Rainfall=8.90" Prepared by Boh_ler Engineering Printed 5/4/2021 HvdroCAD@ 10.00-19 s/n 08955 @ 2016 HvdroCAD Software Solutions LLC Paae 53 Summary for Link DP-1: Inflow Area= 2.217 ac, 90.97%Impervious, Inflow Depth= 7.36" for 100-YR event Inflow = 18.28 cfs @ 12.09 hrs, Volume= 1.359 of Primary = 18.28 cfs @ 12.09 hrs, Volume= 1.359 af, Atten=0%, Lag=0.0 min Primary outflow=Inflow,Time Span=0.00-30.00 hrs,dt=0.02 hrs Link DP-1: Hydrograph -1-4 +I+ + 1 1 + +I + �-I+ +- 1_1 + 1_1 4 �-I ❑Inflow zo/ /_1 1 L I� 1 I—I ,eze . L 11 1-1 1 I—I � L 11 � 1-1 ❑Primary T 1] T 1_1 _,a:a�, L 1] -f1fl1Pw1Arqar—;2--12f7-;1;- 17/ 1 1 t fi 1 1 t 1 1 rt r 1 t fi t 1 t 1+ +1+ + 1-1 + + —I + 1-1 4 �-1+ � 1-1 + 13% /-11 LIJ 11_11 L11 LI_111_11 L11 1 I_11 9ii- - f- - - 1=1 - -l- fit=1tI_ — -l- — l_I - LL 6/ '-I+ +I+ + 1-1 + 1+ 4- 1-1 + 1-1 4 �-1+ 4- 1-1 + sue /-11 LIJ 11_11 _11 LI_111_11 L11 LI_I1 i 2ii � i-1 4- 0 aaaw ..r..../../..i....i:...i....�................................. 0 , 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ,9 20 21 22 23 24 25 26 27 28 29 30 Time(hours) APPENDIX F: STORMWATER CALCULATIONS ➢ MA STANDARD#3-RECHARGE AND DRAWDOWN TIME ➢ MA STANDARD#4- WATER OUALITYAND TSS REMOVAL ➢ CDS WATER O UALITY STR UCTURE SIZING ➢ MOUNDING ANALYSIS AND NARRATIVE ➢ PHOSPHORUS REMOVAL ANALYSIS ➢ WA TER TOWNRAINFALL DATA 64 Pleasant St 64 Pleasant St Watertown, MA Bohler Job Number: M201051 April 30,2021 MA DEP Standard 3: Recharge Volume Calculations Required Recharge Volume-A Soils (0.60 in.) Existing Site Impervious Area (ac) 0.000 Proposed Site Impervious Area (ac) 0.000 Proposed Increase in Site Impervious Area (ac) 0.000 Recharge Volume Required (cf) 0 Required Recharge Volume-B Soils (0.35 in.) Existing Site Impervious Area (ac) 1.231 Proposed Site Impervious Area (ac) 1.250 Proposed Increase in Site Impervious Area (ac) 0.019 Recharge Volume Required (cf) 24 Required Recharge Volume-C Soils (0.25 in.) Existing Site Impervious Area (ac) 0.000 Proposed Site Impervious Area (ac) 0.000 Proposed Increase in Site Impervious Area (ac) 0.000 Recharge Volume Required (cf) 0 Required Recharge Volume-D Soils (0.10 in.) Existing Site Impervious Area (ac) 0.000 Proposed Site Impervious Area (ac) 0.000 Proposed Increase in Site Impervious Area (ac) 0.000 Recharge Volume Required (cf) 0 Total Recharge Volume Required (cf) 24 Recharge Volume Adjustment Factor Impervious Area Directed to Infiltration BMP (ac) 1.250 %Impervious Directed to Infiltration BMP 100% Adjustment Factor 1.00 Adjusted Total Recharge Volume Required (cf) 24 Provided Recharge Volume" Infiltration System#1 1,463 Infiltration System#2 1,465 Total Recharge Volume Provided (cf)l 2,928 Provided areater than or Eaual to Reauired *Volume provided below lowest outlet in cubic feet(cf) Prepared By: Bohler Engineering 352 Turnpike Road Southborough, MA 01772 (508)480-9900 5/3/2021 64 Pleasant St 64 Pleasant St Watertown, MA Bohler Job Number: M201051 April 30, 2021 MA DEP Standard 3: Drawdown Time Calculations Drawdown Time - Infiltration System #1 Volume below outlet pipe (Rv) (cf) 1,463 Soil Type Sandy Loam - B Infiltration rate (K)* 1.02 Bottom Area (sf) 1,166 Drawdown time (Hours)* 14.8 Drawdown Time - Infiltration System #2 Volume below outlet pipe (Rv) (cf) 1,465 Soil Type Sandy Loam - B Infiltration rate (K)* 1.02 Bottom Area (sf) 1,166 Drawdown time (Hours)** 14.8 *Infiltration Rates taken from Rawls Table **Drawdown time = Rv/(K) x (bottom area) 64 Pleasant St 64 Pleasant St Watertown, MA Bohler Job Number: M201051 April 30, 2021 MA DEP Standard 4: Water Quality Volume Calculations Water Quality Volume Required Water Quality Volume runoff(in.)* 0.5 Total Post Development Impervious Area (sf) 54,438 Required Water Quality Volume (cf) 2,268 *Water Quality volume runoff is equal to 0.5 or 1.0 inches of runoff times the total impervious area of the post development project site. Water Quality Volume Provided* Infiltration System #1 1,463 Infiltration System #2 1,465 0 0 0 Total Provided Water Quality Volume (cf) 2,928 Provided qreater than or Equal to Required *Volume provided below lowest outlet pipe in cubic feet(cf) Prepared By: Bohler Engineering 45 Franklin Street Boston, MA 02110 (617) 849-8040 5/3/2021 Location:IPR1 &PR2 A B C D E TSS Removal Starting TSS Amount Remaining BMP' Rate' Load* Removed (B*C) Load (C-D) Deep Sump Catch Basin 0 0.25 1.00 0.25 0.75 Water Quality Unit (� 0.90 0.75 0.68 0.08 N Infiltration System 0.80 0.08 0.06 0.02 > i O O E Cn Cn � Total TSS Removal = 99% Project:164 Pleasant St Prepared By:IBonler *Equals remaining load from previous BMP(E) Date:14/30/2021 which enters the BMP Prepared By: Bohler Engineering 45 Franklin Street, 5th Floor Boston, MA 02110 (617)849-8040 5/3/2021 CIWAWNTECH IDS �alllll��;; ENGINEERED SOLUTIONS �TECHNOLOGIES CDS ESTIMATED NET ANNUAL SOLIDS LOAD REDUCTION BASED ON THE RATIONAL RAINFALL METHOD 64 PLEASANT STREET WATERTOWN, MA Area 0.50 ac Unit Site Designation WQU # 1 Weighted C 0.9 Rainfall Station # 69 t, 5 min CDS Model 1515-3 CDS Treatment Capacity 1.0 cfs Rainfall Percent Rainfall Cumulative Total Flowrate Treated Flowrate Incremental Intensity' Volume' Rainfall Volume cfs cfs Removal (%) (in/hr) 0.02 10.2% 10.2% 0.01 0.01 10.2 0.04 9.6% 19.8% 0.02 0.02 9.6 0.06 9.4% 29.3% 0.03 0.03 9.4 0.08 7.7% 37.0% 0.04 0.04 7.7 0.10 8.6% 45.6% 0.05 0.05 8.5 0.12 6.3% 51.9% 0.05 0.05 6.2 0.14 4.7% 56.5% 0.06 0.06 4.6 0.16 4.6% 61.2% 0.07 0.07 4.5 0.18 3.5% 64.7% 0.08 0.08 3.5 0.20 4.3% 69.1% 0.09 0.09 4.2 0.25 8.0% 77.1% 0.11 0.11 7.7 0.30 5.6% 82.7% 0.14 0.14 5.3 0.35 4.4% 87.0% 0.16 0.16 4.1 0.40 2.5% 89.5% 0.18 0.18 2.3 0.45 2.5% 92.1% 0.20 0.20 2.3 0.50 1.4% 93.5% 0.23 0.23 1.3 0.75 5.0% 98.5% 0.34 0.34 4.3 1.00 1.0% 99.5% 0.45 0.45 0.8 1.50 0.0% 99.5% 0.68 0.68 0.0 2.00 0.0% 99.5% 0.90 0.90 0.0 3.00 0.5% 100.0% 1.35 1.00 0.2 96.8 Removal Efficiency Adjustment2 = 6.5% Predicted %Annual Rainfall Treated = 93.4% Predicted Net Annual Load Removal Efficiency= 90.4% 1 - Based on 10 years of hourly precipitation data from NCDC Station 770, Boston WSFO AP, Suffolk County, MA 2- Reduction due to use of 60-minute data for a site that has a time of concentration less than 30-minutes. Available Models StorageTreatment CapaCity3 Maximum Sediment .. 1515 1.0 26 w/1'added sump 1.0 33 w/2'added sump 1.0 40 w/3'added sump 1.0 47 2015 4 1.4 50 w/1'added sump 1.4 63 w/2'added sump 1.4 75 w/3'added sump 1.4 88 2015 1.4 79 w/1'added sump 1.4 98 w/2'added sump 1.4 118 2020 2.2 90 w/1'added sump 2.2 110 w/2'added sump 2.2 129 2025 3.2 97 w/1'added sump 3.2 117 w/2'added sump 3.2 136 3020 3.9 134 w/1'added sump 3.9 163 w/2'added sump 3.9 191 3030 6.1 157 w/1'added sump 6.1 185 w/2'added sump 6.1 213 4030 7.9 329 w/1'added sump 7.9 379 w/2'added sump 7.9 429 4040 12.4 381 w/1'added sump 12.4 431 w/2'added sump 12.4 482 1. Structure diameter represents the typical inside dimension of the concrete structure.Offline systems will require additional concrete diversion components 2. Depth below pipe can vary to accommodate site specific design. Depth below pipe invert represents the depth from the pipe invert to the inside bottom of concrete structure. 3. Treatment Capacity is based on laboratory testing using OK-1 10(average d50 particle size of approximately 100 microns)and a 2400 micron screen. Sediment Depths Indicating Required Servicing* CDS Model Standard Sediment w/1'added Sump w/2'added Sump Depth Sediment Depth Sediment Depth (in.) (in.) (in.) 1515 18 27 36 2015_4 1 18 30 42 2015 18 30 42 2020 18 30 42 2025 18 30 42 3020 18 30 42 3030 18 39 42 4030 27 39 51 4040 27 39 51 *Based on 75%capacity of isolated sump. Learn more • • .•- GROUNDWATER MOUNDING CALCULATIONS "64 PLEASANT STREET" WATERTOWN,MASS. PROJECT NO.M201051 Methodologv Infiltration Basin 1 and Infiltration Basin 2 for this project are designed with less than 4 feet of groundwater separation. They are also designed to attenuate the 25-year storm event or larger. Therefore, groundwater mounding calculations are required according to MA DEP Stormwater Management Guidelines. The purpose of the calculations is to ensure that the mound will not prevent the full draining of the basin. The mounding analysis must show that the recharge volume will exfiltrate within seventy-two (72) hours. Additionally, it should be verified that the mounding effect will not cause stormwater to surge above the lowest discharge point out of a basin (during the 72-hour period) or raise the water elevation in a nearby resource area. The groundwater mounding analysis was performed by a proprietary program using the Hantush Method with Glover's Solution. Input parameters are site specific and determined based on existing and proposed conditions. The required input parameters are the following: application rate; duration of application; fillable porosity; hydraulic conductivity; initial saturated thickness; length of application area; width of application area; and distance to closest resource area (constant head boundary). Calculations using the Hantush Method are considered conservative due to the fact that the unsaturated soil zone is not incorporated. In practice, this zone will have a significant positive effect on reducing the groundwater mounding under an infiltration basin by allowing horizontal migration. Our unsaturated zone is approximately 2 feet for Infiltration Basin 1 and 2 feet for Infiltration Basin 2. Our lowest outlet in Infiltration Basin 1 is 2.6 feet above the bottom and 2.5 feet above the bottom for Infiltration Basin 2. This requires that the mounding must be less than 4.6 feet and 4.5 feet respectively to ensure that stormwater will not bypass the basin floor and exit out an outlet device. The application rate used is converted from the Rawls value selected for an exfiltration rate in HydroCAD. The duration of application used for the analysis is the 36 hour based duration of the storm event and additional infiltration time. The fillable porosity, hydraulic conductivity, and initial saturated thickness used for the analysis are based on the existing loamy sand soil conditions. The length and width of the application area and the distance to the closest resource are based on the proposed basin size and location. Results Based on the criteria mentioned above, the analysis (see attached) indicates that a mound of approximately 1.721 feet is possible during a 36-hour storm event at Basin 1 and 1.721 feet at Basin 2. These mounds are less than the limits (4.6 feet and 4.5 feet) discussed above. Given these results, we feel as though the basins recharge the stormwater volume within 72 hours as required. This spreadsheet will calculate the height of a groundwater mound beneath a stormwater infiltration basin. More information can be found in the U.S.Geological Survey Scientific Investigations Report 2010-5102"Simulation of groundwater mounding beneath hypothetical stormwater infiltration basins". The user must specify infiltration rate(R),specific yield(Sy),horizontal hydraulic conductivity(0), basin dimensions(x,y),duration of infiltration period(t),and the initial thickness of the saturated zone(hi(0),height of the water table if the bottom of the aquifer is the datum). For a square basin the half width equals the half length(x=y). For a rectangular basin,if the user wants the water-table changes perpendicular to the long side,specify x as the short dimension and y as the long dimension. Conversely, if the user wants the values perpendicular to the short side,specify y as the short dimension,x as the long dimension. All distances are from the center of the basin. Users can change the distances from the center of the basin at which water-table aquifer thickness are calculated. Cells highlighted in yellow are values that can be changed by the user. Cells highlighted in red are output values based on user-specified inputs. The user MUST click the blue"Re-Calculate Now"button each time ANY of the user-specified inputs are changed otherwise necessary iterations to converge on the correct solution will not be done and values shown will be incorrect. Use consistent units for all input values(for example,feet and days) use consistent units(e.g.feet&days or inches&hours) Conversion Table Input Values inch/hour feet/day 2.0400 R Recharge(infiltration)rate(feet/day) 0.67 1.33 0.350 Sy Specific yield,Sy(dimensionless,between 0 and 1) 20.40 K Horizontal hydraulic conductivity,Kh (feet/day)* 2.00 4.00 In the report accompanying this spreadsheet 11.000 x 1/2 length of basin(x direction,in feet) (USGS SIR 2010-5102),vertical soil permeability 26.500 y 1/2 width of basin(y direction,in feet) hours days (ft/d)is assumed to be one-tenth horizontal 1.500 t duration of infiltration period(days) 36 1.50 hydraulic conductivity(ft/d). 15.000 hi(0) initial thickness of saturated zone(feet) 16.72 h(max) maximum thickness of saturated zone(beneath center of basin at end of infiltration period) Ah(max) maximum groundwater mounding(beneath center of basin at end of infiltration period) Ground- Distance from water center of basin Mounding,in in x direction,in feet feet 0 rO.060 20 Re-Calculate Now 40 50 60 Groundwater Mounding, in feet 70 2.000 80 1.800 90 1.600-- 0.037 100 1.400- 0.014 120 1.200 INk - 1.000- 0.800- 0.600 l� 0. 00 0.200 0.000 70 0 20 40 60 80 100 120 140 Disclaimer This spreadsheet solving the Hantush (1967)equation for ground-water mounding beneath an infiltration basin is made available to the general public as a convenience for those wishing to replicate values documented in the USGS Scientific Investigations Report 2010-5102 "Groundwater mounding beneath hypothetical stormwater infiltration basins" or to calculate values based on user-specified site conditions. Any changes made to the spreadsheet(other than values identified as user-specified) after transmission from the USGS could have unintended, undesirable consequences.These consequences could include, but may not be limited to: erroneous output, numerical instabilities, and violations of underlying assumptions that are inherent in results presented in the accompanying USGS published report.The USGS assumes no responsibility for the consequences of any changes made to the spreadsheet. If changes are made to the spreadsheet,the user is responsible for documenting the changes and justifying the results and conclusions. BOHLERI JOB NO. M201051 CALCULATED BY WNG DATE 04-29-21 CHECKED BY ZLR BMP Volume needed for 60% reduction of phosphorus: 4For 60% Phosphorus (P) removal, 0.20 in of runoff needs to be treated. (See Figure 1) 4IR= Runoff Depth for P removal =0.20 in The proposed site has 1 total design area, Design Area 1, which consists of the parking lot site work. DA1 has 1.25 ac of impervious cover and 0.20 ac of pervious cover. See below for the cover type and loading breakdown.The Design Area is treated by two infiltration basins as described below. Table 1 Design Area Cover Type Area (ac) P Export Rate (lb/ac/yr)* DA1 Impervious, HSG B 1.25 1.78 (Commercial) DevPerv, HSG B 0.2 0.13 (Commercial) *From Figure 6 Determining the design storage volume required to achieve 60% phosphorus load reduction: Equation 3-6 (Figure 3)was used to calculate the BMP storage volume needed to treat the runoff depth from the contributing impervious area: DP1: BMP-Volume Required = (IR * Impervious Area * 3,630 CF/ac-in) BMP-Volume Required = (0.20 in *1.25 ac * 3,630 CF/ac-in) BMP-Volume Required =907.5 CF The designed total storage volume above the lowest outlet for both of the proposed basins is 8,938 CF (from HydroCAD). 2,623 CF>907.5 CF 4 OK BOHLERI JOB NO. M201051 CALCULATED BY WNG DATE 04-29-21 CHECKED BY ZLR Determining the phosphorus load reduction provided for the designed systems: 1. P Load = (Impervious Area * Phosphorus Loading Rate) + (Pervious Area * Phos. Loading Rate) **See Table 1 above for the Phosphorous Loading Rates found using Figure 6** P Load = (1.25ac * 1.78 Ib/ac/yr) +(0.20ac * 0.13 Ib/ac/yr) P Load = 2.25 Ib/yr --> Site yields 2.25 Ib/yr of phosphorus Because 60% is required to be removed,the amount of phosphorus removal needed per year is: 2.13 Ib/yr * 0.60= 1.35 Ib/yr 2. Storage volume proposed for the amount of runoff produced by the site: Runoff from impervious area (in) = (2623 CF/1.25 ac) * (12 in/FT) * (1 ac/43,560 SF) =0.58 in 4 0.58 inches of runoff from impervious area is treated. 3. Using Figure 1,for 0.58 in of runoff treated,the amount of phosphorous removal will be 86%. 4 86%>60% (minimum required removal); OK 4. Amount of phosphorus removed per year: P loading= 2.25 Ib/yr (see step#1 above) (0.86) * (2.25 Ib/yr) = 1.94 Ib/yr 4 1.94 Ib/yr of phosphorus is removed by proposed system BOHLERY JOB NO. M201051 CALCULATED BY WNG DATE 04-29-21 CHECKED BY ZLR Figure 3.10:BMP Performance Curve:Infiltration Basin(Soil infiltration rate=1.02 inlhr) BMP Performance Curve: Infiltration Basin (Soil infiltration rate=1.02 inlhr) 100% - 100% 90% �*� r 90% 86% 80% m 70% 70% REPRESENTS TOTAL o E 6010 PHOSPHORUS REMOVAL — 601°50% � � INCLUDING CONTRIBUTING — 5o% � ROOF RUNOFF 40% — 40% p 7 IL 30°/0 30°Io 0 c 20% 20% 10% 10% 0.0 0.2 %A;r0 0.B 0.8 1.0 1.2 1.4 1.6 1.8 2.0 co Physical Storage Capacity:Depth of Runoff from Impervious Area {inches} Total Phosphorus 0 -Volume Figure 1 Source: Methods to Calculate Phosphorus Load Reductions for Structural Stormwater Best Management Practices in the Watershed https://www3.epa.gov/regioni/npdes/stormwater/ma/2014AppendixF-Attachment3.pdf 9.1 Precipitation Data: Unless specified, all design storms shall have a 24-hour duration and all drainage analyses shall use the following precipitation data, adopted from the web tool "Extreme Precipitation in New York and New England" developed jointly by the Northeast Regional Climate Center(NRCC) at Cornell University and the Natural Resources Conservation Service (MRCS), as available at http://precip.eas.comell.edu/for the Town of Watertown centered at Department of Public Works, 124 Orchard Street, as accessed on July 15, 2014 and summarized in the table below: Design Storm 24-Hour Precipitation (Inches) 2-year 3.2 10-year 4.9 25-year 6.2 100-year 8.9 9.2 Hydrologic Analysis Methodology: Existing and proposed stolmwater runoff peal',rates and total volumes shall be estimated using the methods described in Technical Release No. 20 (TR-20) and Technical Release No. 55 (TR-55), where applicable, published by the National Resources Conservation Service (MRCS), United States Department of Agriculture (USDA). 9.2.1 Common design point(s) shall be used for comparison between existing and proposed conditions. 9.2.2 The total length of"sheet flow" in the calculation of Time of Concentration for a subcatchment shall be limited to 100 feet or less for pre-developed conditions, and 50 feet or less for post-developed conditions. The minimum permissible Time of Concentration is 5.0 minutes. 9.2.3 The surface of all ponds, rivers, detention/retention ponds, and other waterbodies shall be assumed to be impervious for the purpose of calculating ground cover. 9.2.4 For purposes of computing runoff, all pervious lands in the site prior to the development shall be assumed to be in good condition regardless of conditions existing at the time of computation. 9.2.5 Stormwater analyses shall be performed using an NRCS (formerly Soil Conservation Service—SCS) Type III 24-hour rainfall distribution. The use of computer modeling techniques, such as HydroCAD, is strongly preferred. 9.2.6 For computer models that have the ability to adjust the time period of the storm analysis, the storm shall be analyzed from time 0.0 (the start of the storm)to at least 30 hours after the start of the storm event. The time increment between analysis points shall be 0.02 hours. 9.2.7 The size of the overall drainage area analyzed in the pre-development and post- development analyses shall be the same. 9.3 Closed Drainage System: LID practices are encouraged when feasible. Where closed drainage networks are proposed, calculations shall be provided in accordance with the following requirements: 9.3.1 Design Storms: The proposed drainage system shall be designed to accommodate a 25-year design storm. Bridges and culverts shall be designed for a 50-year i I Approved and Adopted Page 20 of 32 i APPENDIX G: OPERATION AND MAINTENANCE ➢ STORMWATER OPERA TIONAND MAINTENANCE PLAN ➢ INSPECTION REPORT ➢ INSPECTION AND MAINTENANCE LOG FORM ➢ LONG-TERM POLL UTION PREVENTION PLAN ➢ SPILL PREVENTION ➢ MANUFACTURER'S INSPECTION AND MAINTENANCE MANUALS ➢ BMP MAINTENANCE ACCESS AREAS STORMWATER OPERATION AND MAINTENANCE PLAN 64 Pleasant Street Watertown,MA RESPONSIBLE PARTY DURING CONSTRUCTION: Berkeley Investments 125 High Street Suite 531 Boston,MA 02110 RESPONSIBLE PARTY POST CONSTRUCTION: Berkeley Investments 125 High Street Suite 531 Boston,MA 02110 Construction Phase During the construction phase, all erosion control devices and measures shall be maintained in accordance with the final record plans, local/state approvals and conditions,the EPA Construction General Permit and the Stormwater Pollution Prevention Plan(SWPPP)if applicable. Additionally,the maintenance of all erosion/siltation control measures during construction shall be the responsibility of the general contractor. Contact information of the OWNER and CONTRACTOR shall be listed in the SWPPP for this site. The SWPPP also includes information regarding construction period allowable and illicit discharges,housekeeping and emergency response procedures.Upon proper notice to the property owner,the Town/City or its authorized designee shall be allowed to enter the property at a reasonable time and in a reasonable manner for the purposes of inspection. Post Development Controls Once construction is completed,the post development stormwater controls are to be operated and maintained in compliance with the following permanent procedures(note that the continued implementation of these procedures shall be the responsibility of the Owner or its assignee): 1. Parking lots and on-site driveways: Sweep at least two(2)times per year and on a more frequent basis depending on sanding operations All resulting sweepings shall be collected and properly disposed of off-site in accordance with MADEP and other applicable requirements. Approximate Maintenance Budget: $1,000/year 2. Catch basins,yard drains,trench drains,manholes and piping: Inspect two (2)times per year and at the end of foliage and snow-removal seasons These features shall be cleaned two (2)times per year or whenever the depth of deposits is greater than or equal to one half the depth from the bottom of the invert of the lowest pipe in the catch basin or underground system.Accumulated sediment and hydrocarbons present must be removed and properly disposed of off-site in accordance with MADEP and other applicable requirements. Approximate Maintenance Budget: $500/year per structure. 3. Water Quality Unit(Proprietary Separator): Follow manufacturer's recommendations (attached). Approximate Maintenance Budget: $1,000/year per unit. 4. Underground Infiltration Basins: Preventative maintenance after every major storm event during the first three(3)months of operation and at least twice per year thereafter. Inspect structure and pretreatment BMP to ensure proper operation after every major storm event(generally equal or greater to 3.0 inches in 24 hours) for the first three months. The outlet of the basin, if any, shall be inspected for erosion and sedimentation, and rip-rap shall be promptly repaired in the case of erosion. Sediment collecting in the bottom of the basin shall be inspected twice annually, and removal shall commence any time the sediment reaches a depth of six inches anywhere in the basin. Any sediment removed shall be disposed of in accordance with MADEP and other applicable requirements. Approximate Maintenance Budget: Cleaning - $1,000/year,Inspection- $200/year All components of the stormwater system will be accessible by the owner or their assignee. I : NTECH° ENGINEERED SOLUTIONS CDS° Inspection and Maintenance Guide 101 11111111: PATE H� N��. Y��FIF3,Fir18 '•1 _ "j,� t* � - a US TECHNOLOGIES Maintenance Cleaning The CDS system should be inspected at regular intervals and Cleaning of a CDS systems should be done during dry weather maintained when necessary to ensure optimum performance. conditions when no flow is entering the system.The use of a The rate at which the system collects pollutants will depend more vacuum truck is generally the most effective and convenient heavily on site activities than the size of the unit. For example, method of removing pollutants from the system. Simply remove unstable soils or heavy winter sanding will cause the grit chamber the manhole covers and insert the vacuum hose into the sump. to fill more quickly but regular sweeping of paved surfaces will The system should be completely drained down and the sump slow accumulation. fully evacuated of sediment.The area outside the screen should also be cleaned out if pollutant build-up exists in this area. Inspection In installations where the risk of petroleum spills is small, liquid Inspection is the key to effective maintenance and is easily contaminants may not accumulate as quickly as sediment. performed. Pollutant transport and deposition may vary from However, the system should be cleaned out immediately in year to year and regular inspections will help ensure that the the event of an oil or gasoline spill should be cleaned out system is cleaned out at the appropriate time. At a minimum, immediately. Motor oil and other hydrocarbons that accumulate inspections should be performed twice per year(e.g. spring on a more routine basis should be removed when an appreciable and fall) however more frequent inspections may be necessary layer has been captured.To remove these pollutants, it may in climates where winter sanding operations may lead to rapid be preferable to use absorbent pads since they are usually less accumulations, or in equipment washdown areas. Installations expensive to dispose than the oil/water emulsion that may be should also be inspected more frequently where excessive created by vacuuming the oily layer.Trash and debris can be amounts of trash are expected. netted out to separate it from the other pollutants. The screen The visual inspection should ascertain that the system should be power washed to ensure it is free of trash and debris. components are in working order and that there are no Manhole covers should be securely seated following cleaning blockages or obstructions in the inlet and separation screen. activities to prevent leakage of runoff into the system from above The inspection should also quantify the accumulation of and also to ensure that proper safety precautions have been hydrocarbons,trash, and sediment in the system. Measuring followed. Confined space entry procedures need to be followed pollutant accumulation can be done with a calibrated dipstick, if physical access is required. Disposal of all material removed tape measure or other measuring instrument. If absorbent from the CDS system should be done in accordance with local material is used for enhanced removal of hydrocarbons,the level regulations. In many jurisdictions, disposal of the sediments may of discoloration of the sorbent material should also be identified be handled in the same manner as the disposal of sediments during inspection. It is useful and often required as part of an removed from catch basins or deep sump manholes. 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 would 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 wsb n� 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 - f the pile typically offer less resistance to the end of the rod than r..w consolidated particles toward the bottom of the pile. Once this .• - `'"` measurement is recorded, it should be compared to the as-built ds " drawing for the unit to determine weather the height of the u sediment pile off the bottom of the sump floor exceeds 75%of � the total height of isolated sump. �Ew Diameter Distance from Water Surface Sediment Storage Capacity to Top of Sediment Pile CDS Model ft m ft m y3 m3 FA �I� f �� fcFnaat• � l 00'0 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, stormwater,earth stabilization and wastewater treament products.For information,visit www.ContechES.com or call 800.338.1122 NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS AN EXPRESSED WARRANTY OR AN IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE.SEE THE CONTECH STANDARD CONDITION OF SALES(VIEWABLE 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 Inspection iMaintenance Log CDS Model: Location: Water Floatable Describe Maintenance Date depth to Layer Maintenance Comments Personnel sediment' Thickness' 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. CDS Maintenance Guide-7/18(PDF) STORMWATER MANAGEMENT SYSTEM POST-CONSTRUCTION INSPECTION REPORT LOCATION: 64 Pleasant Street Watertown,MA RESPONSIBLE PARTY: Berkeley Investments 125 High Street Suite 531 Boston,MA 02110 NAME OF INSPECTOR: INSPECTION DATE: Note Condition of the Following (sediment depth, debris, standing water, damage, etc.): Catch Basins: Discharge Points/ Flared End Sections / Rip Rap: Infiltration Basin: Water Quality Units: Other: Note Recommended Actions to be taken on the Following (sediment and/or debris removal, repairs, etc.): Catch Basins: Discharge Points / Flared End Sections / Rip Rap: Infiltration Basin: Water Quality Units: Other: Comments: STORMWA TER INSPECTIONAND MAINTENANCE LOG FORM 64 Pleasant Street— Watertown,MA Stormwater Management Responsible Parry Date Maintenance Activity Practice Performed LONG-TERM POLLUTION PREVENTION PLAN 64 Pleasant Street Watertown,MA RESPONSIBLE PARTY DURING CONSTRUCTION: Berkeley Investments 125 High Street Suite 531 Boston,MA 02110 RESPONSIBLE PARTY POST CONSTRUCTION: Berkeley Investments 125 High Street Suite 531 Boston,MA 02110 For this site, the Long-Term Pollution Prevention Plan will consist of the following: • The property owner shall be responsible for"good housekeeping" including proper periodic maintenance of building and pavement areas, curbing, landscaping, etc. • Proper storage and removal of solid waste (dumpsters). • Sweeping of driveways a minimum of twice per year with a commercial cleaning unit. Any sediment removed shall be disposed of in accordance with applicable local and state requirements. • Regular inspections and maintenance of Stormwater Management System as noted in the "O&M Plan". • Snow removal shall be the responsibility of the property owner. Snow shall not be plowed, dumped and/or placed in forebays, infiltration basins or similar stormwater controls. Salting and/or sanding of pavement/walkway areas during winter conditions shall only be done in accordance with all state/local requirements and approvals. OPERATON AND MAINTENANCE TRAINING PROGRAM The Owner will coordinate an annual in-house training session to discuss the Operations and Maintenance Plan, the Long-Term Pollution Prevention Plan, and the Spill Prevention Plan and response procedures. Annual training will include the following: Discuss the Operations and Maintenance Plan • Explain the general operations of the stormwater management system and its BMPs • Identify potential sources of stormwater pollution and measures/methods of reducing or eliminating that pollution • Emphasize good housekeeping measures Discuss the Spill Prevention and Response Procedures • Explain the process in the event of a spill • Identify potential sources of spills and procedures for cleanup and/or reporting and notification • Complete a yearly inventory or Materials Safety Data sheets of all tenants and confirm that no potentially harmful chemicals are in use. • Trash and other debris shall be removed from all areas of the site at least twice yearly. • Reseed any bare areas as soon as they occur. Erosion control measures shall be installed in these areas to prevent deposits of sediment from entering the drainage system. • Grass shall be maintained at a minimum blade height of two to three inches and only 1/3 of the plant height shall be removed at a time. Clippings shall not be disposed of within stormwater management areas or adjacent resource areas. • Plants shall be pruned as necessary. • In no case shall snow be disposed of or stored in resource areas (wetlands, floodplain, streams or other water bodies). • If necessary, stockpiled snow will be removed from the Site and disposed of at an off-site location in accordance with all local, state and federal regulations. • Deliveries shall be monitored by owner or owner's representative to ensure proper delivery and in the event that a spillage occurs it shall be contained and cleaned up immediately in accordance with the spill prevention program for the project. • Recycle materials whenever possible. Provide separate containers for recycle materials. Recycling products will be removed by a certified waste hauler. SPILL PREVENTION AND RESPONSE PROCEDURES (POST CONSTRUCTION) In order to prevent or minimize the potential for a spill of Hazardous Substances or Oil or come into contact with stormwater,the following steps will be implemented: 1. All Hazardous Substances or Oil (such as pesticides,petroleum products, fertilizers, detergents, acids,paints,paint solvents, cleaning solvents, etc.)will be stored in a secure location,with their lids on,preferably under cover,when not in use. 2. The minimum practical quantity of all such materials will be kept on site. 3. A spill control and containment kit(containing, for example, absorbent materials, acid neutralizing powder,brooms, dust pans,mops,rags, gloves,goggles,plastic and metal trash containers, etc.)will be provided on site. 4. Manufacturer's recommended methods for spill cleanup will be clearly posted and site personnel will be trained regarding these procedures and the location of the information and cleanup supplies. 5. It is the OWNER'S responsibility to ensure that all Hazardous Waste on site is disposed of properly by a licensed hazardous material disposal company. The OWNER is responsible for not exceeding Hazardous Waste storage requirements mandated by the EPA or state and local authorities. In the event of a spill of Hazardous Substances or Oil,the following procedures should be followed: 1. All measures should be taken to contain and abate the spill and to prevent the discharge of the Hazardous Substance or Oil to stormwater or off-site. (The spill area should be kept well ventilated and personnel should wear appropriate protective clothing to prevent injury from contact with the Hazardous Substances.) 2. For spills of less than five(5) gallons of material,proceed with source control and containment, clean-up with absorbent materials or other applicable means unless an imminent hazard or other circumstances dictate that the spill should be treated by a professional emergency response contractor. 3. For spills greater than five(5) gallons of material immediately contact the MADEP at the toll-free 24-hour statewide emergency number: 1-888-304-1133,the local fire department(9- 1-1)and an approved emergency response contractor. Provide information on the type of material spilled,the location of the spill,the quantity spilled, and the time of the spill to the emergency response contractor or coordinator, and proceed with prevention,containment and/or clean-up if so desired. (Use the form provided, or similar). 4. If there is a Reportable Quantity(RQ)release,then the National Response Center should be notified immediately at(800)424-8802;within 14 days a report should be submitted to the EPA regional office describing the release,the date and circumstances of the release and the steps taken to prevent another release. This Pollution Prevention Plan should be updated to reflect any such steps or actions taken and measures to prevent the same from reoccurring. SPILL PREVENTION CONTROL AND COUNTERMEASURE FORM 64 Pleasant Street Watertown,MA Where a release containing a hazardous substance occurs,the following steps shall be taken by the facility manager and/or supervisor: 1. Immediately notify The Watertown Fire Department(at 9-1-1) 2. All measures must be taken to contain and abate the spill and to prevent the discharge of the pollutant(s)to off-site locations,receiving waters,wetlands and/or resource areas. 3. Notify the Watertown Health Department at(617) 972-6446 and the Watertown Conservation Commission at(617) 972-6426. 4. Provide documentation from licensed contractor showing disposal and cleanup procedures were completed as well as details on chemicals that were spilled to the Town of Watertown Health Department and Conservation Commission. Date of spill: Time: Reported By: Weather Conditions: Material Spilled Location of Approximate Agency(s)Notified Date of Spill Quantity of Spill Notification (in gallons) Cause of Spill: Measures Taken to Clean up Spill: Type of equipment: Make: Size: License or S/N: Location and Method of Disposal Procedures, method, and precautions instituted to prevent a similar occurrence from recurring: Additional Contact Numbers: • DEPARTMENT OF ENVIRONMENTAL PROTECTION(DEP) EMERGENCY PHONE: 1-888-304-1133 • NATIONAL RESPONSE CENTER PHONE: (800)424-8802 • U.S. ENVIRONMENTAL PROTECTION AGENCYPHONE: (888) 372-7341 / I /19 as ,a / 570EWAlX � _ EA S,q/VT rPua�IC N xna ,s,a2e'e"r_ 1& VARIABLE WIDTH) CO tpc S♦\rFNO) F.,az, aq Yp I E l Ja �� N88'50 20 E 1 !a laer rr__ _ = Jase ,A- •ti1aa1 a.r Q-f Mr3:n W t \72i65 / IF-21.08, A"ap _ \y.) JSA � ® 7B,N_7 SB/D1Y(FND) ! --�_ SbEWAU( •�I[ _-I- u I{D1 PROP STORMTECHSC-310 STORMWATER 'r J3ee ,a ®•M1IR,g c AylAJP 1, a --- \ RETENTION SYSTEM CHAMBERS,6 .il — J 1 6.18.58+ GPo1S5 7• _ ROWS OF 7 CHAMBERS) & �J .S TOP OF STONE=983 SM a+. TOP OF CHAMBERS=933 J 1 -------------------- °P ?- _ BOTTOM OF CHAMBERS=600 S lii J 1 ■w BOTTOM OF STONE=750 APROX.GROUNDWATER ELEVATION 550 DONCREjE- PRORWOU-2 v TOP Imo' / _`�j T ❑ * 611•'V IN= "<=a< _ .ter A'•lS,p PROP OCS-1 COW. I - - 1 T T * ❑.. WQU'Z INV OUT=806 - <<' a< l`f tiyM. RIM=12.5 1 /Xp 1 T 1 Il _- <_ --!Q.._+ WEIRWALL=100(SEE DETAIL 1Sat I T T - FORD IFICE INFORMATION) w� DMH-1 -- _- INV.INIOUT=BA _ww ISJb ^•W PA ] O ei, 11 LF12'HDPEPIPE _________________ __ \ WW\\II �+ S=0.5% SUBSURFACE JAat ,/I I f CB-4 F'2'HOPE PIPES'°5 `' 7-2LF12•HDPLPIPES 05% INFILTRATION BASIN 1 Now or Former/ l_ 74 LF 72'HOPE PIPE _ INV=00 COMMONWEALTHy Jam- s=0s% IN =10 z f CROSSING SSACHSV F J\ \ i CB-3 _ I/atv1 P TOP oRAI INV=800 l� N .¢ ,J-g PROP CB-3�' SIF 7Z'HDPE PIPE P E / Ql�c�-1 I� 11 ORASS PROP.CB-1 ••p RIM=122 INV.=80 5=15% PROP WQU-1 1PE5=p0% / I�iJJ \ AIE RIM=11.7 NV.=B2 PROP.8-PVC DRAIN (� -� INV=0LI RIM=718/ $ INV,9.0IR� PIPE TO CONNECT � � ��M- ��*! �J t r WETLAND DEUNEAT/ON PERFO17G.60 (Av r, INV INIDMHa)= \ J �7BLE STRIP,- 1 SE EXISTING ,a - WQU-1 ® - BYEPSAONASSOC/ATE5IN � 1 Alr / � � PROP DMH-1 SERVICE ^ ® 2G 59 LF 15'HOPE PIPE V� OCTOBER OF 2016. I I / «7Z. 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I INV.OUT=867 CB-1 CB-2 T / / INV-863 AI PROP VROOF DRAIN I� u CROSSING / • • S COLLECTION PIPE(TYP) - TOP 6R=6.08 / !,A 15'DRARAC CROSSING NSS ING3 150'WE7WD BU'7ZR TOP 6'SEWER5703 4 75 LF 72"HDSE PIPE 6'ROOF INV=000 / y� x EXISTING 3 STORY al' + PROP CONNECT EX ONTO Ja �. 1Yil'' bq9 � BUILDING PROP���4 .A N 46,850± SF FOOTPRINT WINSPOUTS TO BE TIED Jp� - IOA6 INTO PERIMETER ROOF DRAIN WITH CAST IRON BOOT AND CLEANOUT(TYP) �i2h '00 ER WEIZAND BUFF IE INV.=B 6 BASED J PROP 8"ROOF DRAIN _ o - --- Y l` •-L N _0 s — - - - PROP INV=ON / EB - COLLECTION PIPE RAI) 5 4 PROP COO EXCDIMH / NOW or RMR OPF�eNy CP[P BOOK 71579, PAW 48 INv.=75 f /5 as J � 1 am ...,.r,vM A, __ a7 /Ill/Ap / 48 LF 12'HDPE PIPE _ -- / INV.=6.5� PROP.SUBSURFACE 5=06% ' o_ Cg 5 CB5 INFILTRATION BASIN 21 HOPE R OCS-2 .2 � =625 I / /' INV.INIOUT=60 N ,P\PFS• ® \t1�G� f4V INV.=6� /fO LF IX.,EPIPE INV.=6.0� I I 50'Z DOFFER s INV=65 , S 5% 65 LF 15"HDPEPIPE8-0.0% �NO BUF(D 13 LF 12'HDPE PIPE .J to J ® I a �Q -- \ INV=75 5=05% M-tas CB-6 12'8DPE PIPES=0.5% \ 3 PROP 0"PVC ROOF / CB-6 �-in �Y �\674. DRAIN PIPE(TYR) �- & \ FEMA 20NE AE LINE BASE ` 4ae / INV.=67 ( \� G am PROP WOU-3 I Q� L� WQU-3 / FLOOD ELEVATIONV BASED ON \ PROP STORMTECHSC310 STO NIV.=(CBE)=8.32 TOPOGRAPHIC SURVEY RETENTION SYSTEM(42 CHAMBERS;6 INV IN IN(CB-6)==32 A) _ ROWS OF 7 CHAMBERS / WETLAND DEPSILON N PERFORMED ) INV OUT=s07 BY EPSILON ASSOCI4TES IN ��e \\ - TOP OF STONE=]83 � NOW 0/f +e TOP OFCHAMBERS=733 ro \ OJmle/%' OCTOBER OF 2016. �� \\ \ f s BOTTOM OFCHAMBERS CROSSRA,{� [� &WK DEUNEAT/ON PERFORMED \ BOTTOM OF STONE=5.50 f 'k OEF'T 247051 BY EPSILON ASSOCIATES IN M� J �a\`\\\ INV APPROX GROUNDWATER ELEVATION * [CO�7152D OCTOBER DF20,6. 4 1 BMP MAINTENANCE FEMA ZONE AE LINE IB \ \\\ \ \ " O' \ ACCESS AREAS FLOOD ON TOPOGRAPHIC SURVED \ �\ \� \ + 64 PLEASANT STREET •-"'�V \\ \ \ N B \ / WATERTOWN,MA V0 J � cS'�'�l�F,�, rBM-2 PREPARED BY H h ``� FEMA ZONE AE LINE \\\ \` CMow or ROSS ,* `/J3+ BASED ONFIRM J,>• [COr22D BOHLER INV.� SCALE:1"=40'DATE:04/29/2021