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07/13/2022 - Stormwater Report - -
STORMWATER REPORT I\Aerrimack MAC Storage Building Co ege, PREPARED FOR EST. 1947 Merrimack College 315 Turnpike Street North Andover, MA 01845 978.837.5000 PREPARED BY vh�b 101 Walnut Street PO Box 9151 Watertown, MA 02471 617.924.1770 0 710 712,02,2, t iirim t ir°I[: 1 ,irt Table of Contents Checklist for Stormwater Report...................................................................................................2 StormwaterReport Narrative.........................................................................................................3 ProjectDescription............................................................................................................................................................3 SiteDescription...................................................................................................................................................................3 ExistingDrainage Conditions........................................................................................................................................4 ProposedDrainage Conditions....................................................................................................................................5 Environmentally Sensitive and Low Impact Development (LID) Techniques................................5 RegulatoryCompliance.................................................................................................................10 Massachusetts Department of Environmental Protection (DEP)—Stormwater Management Standards............................................................................................................................................................................10 Standard 1: No New Untreated Discharges or Erosion to Wetlands.............................................10 Standard 2: Peak Rate Attenuation.............................................................................................................10 Standard3: Stormwater Recharge...............................................................................................................11 Standard4:Water Quality...............................................................................................................................12 Standard 5: Land Uses with Higher Potential Pollutant Loads (LUHPPLs)...................................12 Standard6: Critical Areas................................................................................................................................13 Standard 7: Redevelopments and Other Projects Subject to the Standards only to the Maximum Extent Practicable.................................................................................................13 Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Controls.........................................................................................................................................13 Standard 9: Operation and Maintenance Plan........................................................................................14 Standard 10: Prohibition of Illicit Discharges..........................................................................................14 Local Municipal Rules and Regulations..................................................................................................................15 Standard A: Low Impact Design (LID).........................................................................................................15 Standard B: Hydrologic and Hydraulic Criteria.......................................................................................15 StandardC: Recharge.......................................................................................................................................15 StandardD:Water Quality..............................................................................................................................15 StandardE: Redevelopment...........................................................................................................................15 StandardF: Landscape Design......................................................................................................................15 Appendices Appendix A: Standard 1 Computations and Supporting Information.....................................................1 Appendix B: Standard 2 Computations and Supporting Information.....................................................1 i Table of Contents S,tormwate [:Zeport AppendixC: Standard S Computations and Supporting Documentation.............................................1 AppendixC, Standard 4 Computations and Supporting Information.....................................................1 AppendiuE Standard 6 Supporting Information............................................................................................1 AppendixF: Standard 1O Illicit Discharge Statement ---------1 x Table orContents List of Tables Table No. Description Page ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... Table 1 Wetland Resource Areas..................................................................................................................4 Table 2 Existing Conditions Hydrologic Data..........................................................................................4 Table 3 Proposed Conditions Hydrologic Data......................................................................................5 Table 4 Peak Discharge Rates (cfs)............................................................................................................11 iii Table of Contents t iirir er[:Zepart Checkl*lst for Stormwater Report 2 Checklist for Stormwater Report Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checkl'ist 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, Report Stormwater the Stter Re which should provide more substantive and detailed information but is offered use only the tab p ( p ) 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. 1 The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included in the Stormwater Report,the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the post-construction best management practices. 2 For some complex projects,it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan in the Stormwater Report. In that event,the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. swcheck•04/01/08 Stormwater Report Checklist•Page 1 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program � Checklist for Stormwater Report 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 AA A OF MgssqC�o JEFFREY W. o KOETTERITZ CIVIL -o No.50595 Q7 STE`��`� Fss1ONAL 6/28/2022 Signature and Date _AL0 7VIII, Awl mole,, ,ep ............"" Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment? ❑ New development ❑ Redevelopment M Mix of New Development and Redevelopment swcheck•04/01/08 Stormwater Report Checklist•Page 2 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program � Checklist for Stormwater Report 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) M 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 M Other(describe): Infiltration Basin Standard 1: No New Untreated Discharges M 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. swcheck•04/01/08 Stormwater Report Checklist•Page 3 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checkl'ist 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. 1 80%TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used. swcheck•04/01/08 Stormwater Report Checklist•Page 4 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checkl'ist 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. swcheck•04/01/08 Stormwater Report Checklist•Page 5 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program � Checklist for Stormwater Report Checklist (continued) Standard 4: Water Quality (continued) ❑ The BMP is sized (and calculations provided) based on: M 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. El 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. swcheck•04/01/08 Stormwater Report Checklist•Page 6 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program � Checklist for Stormwater Report Checklist (continued) Standard 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 amulti-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 amulti-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 M 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. swcheck•04/01/08 Stormwater Report Checklist•Page 7 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program � Checklist for Stormwater Report Checklist (continued) Standard 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 M 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: El 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. swcheck•04/01/08 Stormwater Report Checklist•Page 8 of 8 t irir heir IlZeport lulu Stormwater Report Narrative This Stormwater Report has been prepared to demonstrate compliance with the Massachusetts Stormwater Management Standards in accordance with the Massachusetts Wetlands Protection Act Regulations (310 CMR 10.00) and Water Quality Certification Regulations (314 CMR 9.00). This report also demonstrates compliance with the North Andover Stormwater Management and Erosion Control Regulations for Stormwater design and mitigation via section 250-27, A-F. ��rloieclllt IIIIIIIIIIIIIIII uuuuuuuu lyuul uuu uuum'lllV IIIIIIIullllll II The Applicant, Merrimack College, is proposing to construct a storage building for Merrimack Athletics use. The Project includes a proposed 3,200 square foot (sf), pre-engineered storage building to house equipment for the College athletics programs.Associated utility connections and stormwater management improvements will be conducted as well.The project is not considered a Land Use with Higher Potential Pollutant Loads (LUHPPL). S 0111111 teI1 III III IIIIIIII0 0 Puuu m 0 m�i II The Project Site is an approximately 0.4-acre parcel of land located on the Merrimack College campus (the "Site") located at 315 Turnpike Street in North Andover, Massachusetts (see Figure 1). The Site lies within the surface watershed of Shawsheen River and is bounded by Turnpike Street (Routes 125 and 114) to the north and east, the Merrimack Athletics Complex to the south, and Walsh Way to the west. See Figure 1, Site Locus Map. Wetland Resource Areas on the Site include the following: Table 1 Wetland Resource Areas Critical Zone 1 or ORW or Zone II Area Zone A SRW or IWPA Name (yes/no) (yes/no) (yes/no) (yes/no) Other Wetland 1 No No No No WF1-100 to WF1-110 Wetland 2 No No No No WF2-98 to WF2-120 For additional information regarding the wetland resource areas present on the site see the Project Notice of Intent prepared by VHB dated July, 2022. 3 Stormwater Report Narrative t irir a t it[:Zeport According to the National Resources Conservation Service (NRCS), surface soils on the Site include Ridgebury and Woodbridge Fine Sandy Loams, 0 to 3 percent slopes. On-site soils are classified as Hydrologic Soil Groups (HSG) C/D and D. Based on the soil evaluation included in Appendix C, the Site is not considered to be within an area of rapid infiltration (soils with a saturated hydraulic conductivity greater than 2.4 inches per hour). um uuuuuuol I Im p IIII IIII IIIIII IIIIIIIII e C o 0��l S Under existing conditions, the Site is a mix of impervious surface and wooded areas with generally flat topography. Figure 2 illustrates the existing drainage patterns on the Site. Currently, the Site is comprised of 1 drainage area as untreated stormwater runoff flows to 1 Design Point, which has been identified as DP-1. Table 2 below provides a summary of the existing conditions hydrologic data. Table 2 Existing Conditions Hydrologic Data Time of Design Area Curve Concentration Drainage Area Discharge Location Point (Acres) Number (min) Drainage Area 1 Wetland 1 DP-1 0.36 90 5 I I uuuuuuu IIIIIIIII a IVuuu�III Ca���1111111d��� uum ulumo III maul Figure 3 illustrates the proposed "post construction" drainage conditions for the project.As shown, the Site will be divided into 3 drainage areas that discharge treated stormwater to the 1 existing Design Point. Table 3 below provides a summary of the proposed conditions hydrologic data. Table 3 Proposed Conditions Hydrologic Data Time of Design Area Curve Concentration Drainage Area Discharge Location Point (Acres) Number (min) Drainage Area 11 Wetland 1 DP-1 0.26 95 5 Drainage Area 12 Wetland 1 DP-1 0.05 91 5 Drainage Area 13 Wetland 1 DP-1 0.05 87 5 The site design integrates a comprehensive stormwater management system that has been developed in accordance with the Massachusetts Stormwater Handbook.The proposed stormwater management system has been designed to treat one half inch Water Quality Volume. 4 Stormwater Report Narrative t iirir tor[:Zeport n v nnnnn i r o n m e nta��d�y Sensiti I�and �� ow ��hmpac ��D I�ni ni nnnnn. nit noon II nit noon nnnrta nn !`-edhniiques Low Impact Development (LID) techniques and stormwater Best Management Practices (BMPs) are implemented into the site design to the best extent practicable and includes a surface infiltration basin with a filter strip to promote water quality, reduction of peak flow to surrounding wetlands, and a reduction in vehicular impervious area. In general, stormwater from the proposed impervious surfaces is directed to sheet flow to the proposed surface basin prior to overflowing into the adjacent wetlands. 5 Stormwater Report Narrative t o iir"rnwater If:fiel in Figure 1 Site Locus Map 6 Stormwater Report Narrative \\vhb.com\gbl\prOj\Wat-LD\1 1625.25 Butler Building\cad\ld\Eng\Stormwater\1 1625.25-Site Locus.dwg --imemoriael ;t,S�- 7 Fark (Al 4 5r 25 ............ _AO W V 133 .......... it Aiid 0 "A,ridv 7"1 1P .. ......... r7l" 1114 0 r 1114 eE A-0 r 170 4, L IFFI fI ? '44 7 3,f) JF 133 /7"W' VP t .7 Site - 11 40.�hC "'S 0 4F VO, # t w, jr J 0 0 4 1(7, FIR v_17 1;II�Lo. 1, 1 got IF IF 74.9 ......... A 1% 7�7_7 _7 I j, �6� XI, 0 .............. V'r .A ,�x 0, J 2 011 125 'IV OP K 'MY 4k� . V IF eo ,�,) -,46111 46 4, 13M ....... IN 7 'XI hbi� Site Locus Map Figure 1 Merrimack MAC Storage Building 315 Turnpike Street July 7, 2022 0 1000 200OFeet North Andover, MA t o iir"mwater If:fiel in Figure 2 Existing Drainage Areas 7 Stormwater Report Narrative \\vhb.corn\gbl\proj\Wat-LD\11625.25 Butler Building\cad\Id\Eng\Stormwater\11625.25-DRAINAGE-EX.dwg /00 19 g� Le end � SYMBOLS X DESIGN POINT 1 DRAINAGE AREA DESIGNATION , X POND o t S -'� 2 5 310A ' LINETYPES DRAINAGE AREA BOUNDARY \\ � _ _ _ �_ TIME OF CONCENTRATION FA-10( W FLOW LINE DP-1 SOIL TYPE BOUNDARY 100'BUFFER ZONE a� WF2-102 WETLAND BOUNDARY WF-XXX WF-XXX F1-108 _ W - 3 3 � SCS SOIL CLASSIFICATIONS RIDGEBURY FINE SANDY ������������� ���� '] LOAM,0 TO 3 PERCENT a 7QA — SLOPES __ : WOODBRIDGE FINE SAND Y ........... ................ ................. ................ ................. ......................' � z a a,,,,,,,,,,,,,,,,,, 31 QA LOAM,0 TO 3 PERCENT SLOPES O IMPERVIOUS AREAS O BUILDING a O l ROADWAY QN GRASS GRAVEL WOODLANDS N'oVhb Existing Drainage Conditions Figure 2 Merrimack MAC Storage Building 7/7/2022 0 10 20 Feet North Andover,MA t o iir"mwater If:fiel in Figure 3 Proposed Drainage Areas 8 Stormwater Report Narrative \\vhb.corn\gbl\proj\Wat-LD\11625.25 Butler Building\cad\Id\Eng\Stormwater\11625.25-DRAINAGE-PR.dwg DAM AND SEED WITH NEW � O Legend .AND WETLAND \I e g SERVATION/WILDLIFE MIX 1\O DRIP STRIP SYMBOLS 80' -)IN#1 \ O EXTENTS OF EXISTING '_43.9 �'��., � f � DESIGN POINT IMPI� -2 43.4 \�A; ` VEH�CULOAR US SURFACE ,, \ _ \,\ , V=242.9 1 PROPOSED I \ DRAINAGE AREA a. x ... \ DESIGNATION f „� � oo_ fj z S ®® e POND S a � 25 + P-1 LINETYPES Q �. 310A 1 2 \ H F DRAINAGE AREA BOUNDARY p-q a -10� TIME OF CONCENTRATION I t. -_ �3 WFA FLOW LINE SOIL TYPE BOUNDARY a �� __€ AE g WF2-102 + 100'BUFFER ZONE �•� WETLAND BOUNDARY DI W-XXX W-F F XXX WF1-108 .� PANS, SCS SOIL CLASSIFICATIONS i RIDGEBURY FINE SANDY ET EXISTING PAVEMENT LOAM,0 TO 3 PERCENT 70A ®e � SLOPES .E E �; „ . WOODBRIDGE FINE SANDY <, .......... ................ ........................ .... 1 A PAVE _ 4 ...................... 3 LOAM,0 TO 3 PERCENT SLOPES IMPERVIOUS AREAS BUILDING PAVEMENT MILL ® _ &OVERLAY ,"% _ EXISTING GARAGE aN �0, DOORS TO REMAIN ROADWAY a GRASS EXISTING M ERRI MACK GRAVEL ATHLETICS CENTER WOODLANDS N'OVhb Proposed Drainage Conditions Figure 3 Merrimack MAC Storage Building 7/7/2022 0 10 20 Feet North Andover,MA 'torir heir I[:Zep oirt lulu Regulatory Compliance IIII IIIIII IIIIIIIII i i i I uu°I uuuuuuuuu I I P � I uuuum Illllmulluuu� Iluouuuulll uuuuuuuuuu luuuuu IIIIIIIIullllll IIIIIIIIIIIIIIIIIII uuuulmp "'ll I I P uuuuuuuuu I I I� ul uuu umuu uuumuuu I uu p ul Iluuuum I I�uuu uuum uuu uuum IIIIII uluum IIIIIIIIIIII IIIIIIIIIIIIIIIIIIII uuuuuuuuuuuuuuuuum IIII IIIIII IIIIIIIII ul�I ���� � uuu S''Ita d a����o-d s As demonstrated below, the proposed Project fully complies with the DEP Stormwater Management Standards. II III II ° II °°°° iisdharges III IIIII III °to We°t a I d s The Project has been designed to comply with Standard 1. The Best Management Practices (BMPs) included in the proposed stormwater management system have been designed in accordance with the Massachusetts Stormwater Handbook. Supporting information and computations demonstrating that no new untreated discharges will result from the Project are presented through compliance with Standards 4 through 6. All proposed Project stormwater outlets and conveyances have been designed to not cause erosion or scour to wetlands or receiving waters. Outlets from closed drainage systems have been designed with flared end sections and stone protection to dissipate discharge velocities. Overflows from BMP's that impound stormwater have been designed with stone channels to protect downgradient areas from erosion. Computations and supporting information for the sizing and selection of materials used to protect from scour and erosion are included in Appendix A. II III nua IIIIII o I The Project has been designed to comply with Standard 2. The rainfall-runoff response of the Site under existing and proposed conditions was analyzed for storm events with recurrence intervals of 2, 10, 2S and 100 years. The results of the analysis, as summarized in Table 4 below, indicate that there is no increase in peak discharge rates between the existing and proposed conditions. Computations and supporting information regarding the hydrologic modeling are included in Appendix B. 10 Regulatory Compliance 'torir er I[:Zeport Table 4 Peak Discharge Rates (cfs) Design Point 2-year 10-year 25-year 100-year Design Point: DP-1 Existing 0.9 1.5 2.0 3.0 Proposed 0.9 1.4 1.9 2.8 tandard I S tormwa ter Recharge Recharge BMPs are proposed only to the maximum extent practicable due to poor soils and a high groundwater table. Soil evaluation (including NRCS Web Soil Survey and Geotechnical Report) and supporting information is included in Appendix C. S"'tandard 4: Wa"'te il ty The Project has been designed to comply with Standard 4 to the maximum extent practicable due to the site being comprised of C and D soils, and proximity to estimated seasonal high groundwater table (ESHGWT). The proposed stormwater management system implements a treatment train of BMPs that has been designed to provide 80%TSS removal of stormwater runoff from 0.5-inches over all proposed impervious surfaces, achieved by sheet-flowing runoff from the impervious surfaces to a proposed infiltration basin with filter strip. Computations and supporting information, including the Long-Term Pollution Prevention Plan, are included in Appendix D. S°' II IIF IIUsesIIIII°'""' ����iilgher ���,'Io II 'IIIII o °' II nnt ��� 0000io 0000io U�� nn �;.) 000� 0000io i The Project is not considered a LU H PPL. S"'tandard 6: Cril"' IIIII reas The Project will not discharge stormwater near or to a critical area. Proposed source controls and pollution prevention measures have been identified in the Long-Term Pollution Prevention Plan included in Appendix D. Refer to Appendix E for Critical Areas Figure. 11 Regulatory Compliance torir heir I[:Zep oirt S ta e c nnnnnn � Redevd�bpmen niniI IrkIII Irk ��3 Irk � Subjecthe S°'tandards a °'to °'the °'ten°' ?rac°'""'i��c a b��e The Project is a redevelopment and has been designed to comply with Stormwater Management Standard 3 and 4 to the maximum extent practicable. The remaining Standards have been met completely. Refer directly to each Standard for applicable computations and supporting information demonstrating compliance with each. S"'tandard 8: Cons"' III "' IIIII II °°° II IIIII "' IIIII II 3reven"' IIIII n andIII IIIII III n d S e d il m e I "'It a"'It iIII o I II °brd�s The Project will disturb approximately 0.4 acres of land and is not required to obtain coverage under the Environmental Protection Agency (EPA) National Pollutant Discharge Elimination System (NPDES) Construction General Permit. In lieu of the Stormwater Pollution Prevention Plan (SWPPP) required under NPDES, a Construction Period Pollution Prevention and Erosion Sedimentation Control Plan has been included as part of the Long-Term Operation & Maintenance Plan included in Appendix D. II IIId 9.- Opera t IIIII II IIMai�hn°'t e n a n c e a II In compliance with Standard 9, a Post Construction Stormwater Operation and Maintenance (O&M) Plan has been developed for the Project. The O&M Plan is included in Appendix D as part of the Long-Term Pollution Prevention Plan. S°'tandard 10: ���)rohiibii°'It i��o I °' ii C ii°'It Dilsdharges Sanitary sewer and storm drainage structures remaining from previous development which are part of the redevelopment area will be located and removed, if needed, and re-incorporated into updated sanitary sewer and separate stormwater sewer systems or will remain in their existing location.The design plans submitted with this report have been designed so that the components included therein are in full compliance with current standards. No statement is made with regard to the drainage system in portions of the site not included in the redevelopment project area. The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges. muppl 11 uuuumuuuuu o c a pw um u e s ° d g u um uuu uuum As outlined below, the proposed Project complies with the Town of North Andover Stormwater Management and Erosion Control Regulations to the maximum extent practicable. III III II ��',,",)esiign (��...........����[)) The Project proposes to utilize a surface infiltration basin with filter strip to provide water quality treatment as noted under DEP Standard #4. 12 Regulatory Compliance 'torir heir I[:Zep oirt S°' II III °°°° III IIIII II °°°° III° IIIIICrii°' III IIIII A hydrologic analysis has been performed per TR-55 methodology as included in Appendix B and DEP Standard #2 above. Rainfall events have been used in the analysis per the Town of North Andover requirements. tandar rge Recharge BMPs are proposed only to the maximum extent practicable due to poor soils and a high groundwater table. See DEP Standard #3 and Appendix C. S"' II III "' II il"'ty The proposed infiltration basin has been sized to meet the water quality volume equivalent to 0.5-inches over the net impervious area of the Project. Due to the site being comprised of C and D soils and proximity to ESHGWT, the standard is noted as being met to the extent practicable. See DEP Standard #4 and Appendix D. III III °°� ° men°' The Project is a redevelopment and meets DEP Standards#3 and #4 to the maximum extent practicable, due to the site being comprised of C and D soils, and proximity to ESHGWT. S"'tandard ...........a II d s c a p°°°° °°°°s IIIII g I The Project is proposed to include New England Conservation/Wildlife Mix in the infiltration basin given the proximity to ESHGWT. 13 Regulatory Compliance Stormwater Report Appendix A: Standard 1 Computations and Supporting Information > Pipe Sizing Calculations A-1 Appendix A: Standard 1 Computations and Supporting Information t irir t it I[:Ze1 ,irk 0 ,ill i„ i i�i�z i o g C a (1.11111�1:u a""'It 0 The closed drainage system was designed for the 25-year storm event, in accordance with standard engineering principles. Drainage pipes were sized using Manning's Equation for full-flow capacity and the Rational Method. A-3 Appendix A: Standard 1 Computations and Supporting Information 101 Walnut Street -`Vhb Watertown,MA 02472 P617.924.1770 Storm Drainage Computations Project MC Storage Building Project# 11625.25 Design Parameters: Design Storm: 25 Year Calculated by NS Date 27-Jun Checked by JK Date 27-Jun ke= 0.2 LOCATION AREA C C x A SUM FLOW TIME(MIN) i� DESIGN CAPACITY PROFILE INLET CONTROL OUTLET CONTROL JUNCTION LOSSES DESCRIPTION FROM TO (AC.) C x A PIPE CONC Q V n PIPE SLOPE Q full V full LENGTH FALL RIM INV INV W.S.E. Freeboard HW/D HW H TW or ho HW Km Kd H loss TIME cfs fps SIZE ft^3/s ft/s ft ft UPPER LOWER ft ft ft ft ft ft ft junction junction junction TD-101 FES-102 0.01 0.90 0.01 0.01 0.12 5.0 8.6 0.1 2.0 0.01 6 0.0071 0.6 3.1 14 0.10 244.0 243.0 242.9 2410 1_0 0.00 0.00 0.0 0.0 0.00 0.20 0.80 0.06 \\vhb.com\gbl\prof\Wat-LD\11625.25 Butler Building\ssheets\11625.25-Pipe Sizing Calculations-HGL CLOSED DRAINAGE SYSTEM CALCULATIONS Page 1 't trim t it I[Ze I ,rt Appendix Be. Standard 2 Computations and 0 Supporting Information The rainfall-runoff response of the Site under existing and proposed conditions was evaluated for storm events with recurrence intervals of 2, 10, 25 and 100-years. Rainfall volumes used for this analysis were based on the Natural Resources Conservation Service (NRCS) Type III, 24-hour storm and Section 250-27 of the North Andover Stormwater Management and Erosion Control Regulations for the site: 3.2,4.8, 6.0, and 8.6 inches, respectively. Runoff coefficients for the pre- and post-development conditions, as previously shown in Tables 2 and 3 respectively, were determined using NRCS Technical Release 55 (TR-55) methodology as provided in HydroCAD. Drainage areas used in the analyses were described in previous sections and shown on Figures 2 and 3. The HydroCAD model is based on the NRCS Technical Release 20 (TR-20) Model for Project Formulation Hydrology. B-1 Appendix B:Standard 2 Computations and Supporting Information brim fir I[:Ze ,rt uuuumuuuu uuumuum A���llllllllllllia uuumuuuuuu. uuu uuum uuu uuum i 6-2 Appendix 6:Standard 2 Computations and Supporting Information � DP-1 I---. Existing Drainage Area Design Point #1 1 Subcat ReachPondLink Routing Diagram for 1162525-EX Prepared by VH6, Printed 6/29/2022 HydroCAD010.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC 1162525-EX Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 3 Area Listing (all nodes) Area CN Description (sq-ft) (subcatchment-numbers) 21620 84 50-75% Grass cover, Fair, HSG D (1) 81250 98 Impervious (1) 41990 79 Woods, Fair, HSG D (1) 15,860 90 TOTAL AREA brim fir[:Zeport 2. e II S torm t .................... �,�,:,X ii s t ii II 9 6-3 Appendix B:Standard 2 Computations and Supporting Information 1162525-EX Type ///24-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 4 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1: Existing Drainage Area 1 Runoff Area=15,860 sf 52.02% Impervious Runoff Depth=2.17" Tc=5.0 min C N=90 Runoff=0.92 cfs 2,866 cf Link DP-1: Design Point#1 Inflow=0.92 cfs 2,866 cf Primary=0.92 cfs 2,866 cf Total Runoff Area= 15,860 sf Runoff Volume =2,866 cf Average Runoff Depth =2.17" 47.98% Pervious = 7,610 sf 52.02% Impervious= 8,250 sf 1162525-EX Type 11124-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 1: Existing Drainage Area 1 Runoff = 0.92 cfs @ 12.07 hrs, Volume= 2,866 cf, Depth= 2.17" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2-YR Rainfall=3.20" Area (sf) CN Description 87250 98 Impervious 27620 84 50-75% Grass cover, Fair, HSG D 47990 79 Woods, Fair, HSG D 157860 90 Weighted Average 77610 47.98% Pervious Area 87250 52.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 1: Existing Drainage Area 1 Hydrograph � El Runoff 0.92 cfs T e ll 24�h R R i ifo I I 0" Ru ff::Ar a 15,8 0::s u ff VOW =2,8 6 c Runo f p h A 7" ° T 5,0 i LL CN=.. ........ 0 e 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) 1162525-EX Type 11124-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Pape 6 Summary for Link DP-1: Design Point #1 Inflow Area = 15,860 sf, 52.02% Impervious, Inflow Depth = 2.17" for 2-YR event Inflow = 0.92 cfs @ 12.07 hrs, Volume= 2,866 cf Primary = 0.92 cfs @ 12.07 hrs, Volume= 2,866 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Link DP-1: Design Point#1 Hydrograph M Inflow � o.szors Primary 0.92c`S nfl ow A e a 5, 6 FM u 3 0 LL O w 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) brim fir[:Zeport 10...........Yea r S tor m t .................... X ii S tii II g 6-4 Appendix B:Standard 2 Computations and Supporting Information 1162525-EX Type ///24-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 7 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1: Existing Drainage Area 1 Runoff Area=15,860 sf 52.02% Impervious Runoff Depth=3.68" Tc=5.0 min CN=90 Runoff=1.53 cfs 4,869 cf Link DP-1: Design Point#1 Inflow=1.53 cfs 4,869 cf Primary=1.53 cfs 4,869 cf Total Runoff Area= 15,860 sf Runoff Volume =4,869 cf Average Runoff Depth = 3.68" 47.98% Pervious = 7,610 sf 52.02% Impervious= 8,250 sf 1162525-EX Type 11124-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 1: Existing Drainage Area 1 Runoff = 1.53 cfs @ 12.07 hrs, Volume= 4,869 cf, Depth= 3.68" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 10-YR Rainfall=4.80" Area (sf) CN Description 87250 98 Impervious 27620 84 50-75% Grass cover, Fair, HSG D 47990 79 Woods, Fair, HSG D 157860 90 Weighted Average 77610 47.98% Pervious Area 87250 52.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 1: Existing Drainage Area 1 Hydrograph Runoff 1.53 cfs HI T e ll 4 :h '11f 0 101IN% R i f ll 80 ' Rulloiff,:Ar a 15, 0 s 1X i ————--------------------------.... ................. U" -4--80, 9 C ........................... R ff-Volu YI oi ep h:= 8 ° T 5.01, i LL =9 o 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) 1162525-EX Type 11124-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Pape 9 Summary for Link DP-1: Design Point #1 Inflow Area = 15,860 sf, 52.02% Impervious, Inflow Depth = 3.68" for 10-YR event Inflow = 1.53 cfs @ 12.07 hrs, Volume= 4,869 cf Primary = 1.53 cfs @ 12.07 hrs, Volume= 4,869 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Link DP-1: Design Point#1 Hydrograph EM Inflow 1.53 cfs El Primary 1.53 cfs nflow A ea .......... ........................................ -------------------------------------- N u 3 0 LL r O 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) brim fir[:Zeport 25 - II r m t .................... �,�,:,X IIIII s t ii�n 9 6-5 Appendix B:Standard 2 Computations and Supporting Information 1162525-EX Type ///24-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 10 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1: Existing Drainage Area 1 Runoff Area=15,860 sf 52.02% Impervious Runoff Depth=4.85" Tc=5.0 min CN=90 Runoff=1.98 cfs 6,405 cf Link DP-1: Design Point#1 Inflow=1.98 cfs 6,405 cf Primary=1.98 cfs 6,405 cf Total Runoff Area= 15,860 sf Runoff Volume = 6,405 cf Average Runoff Depth =4.85" 47.98% Pervious = 7,610 sf 52.02% Impervious= 8,250 sf 1162525-EX Type 11124-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment 1: Existing Drainage Area 1 Runoff = 1.98 cfs @ 12.07 hrs, Volume= 6,405 cf, Depth= 4.85" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 25-YR Rainfall=6.00" Area (sf) CN Description 87250 98 Impervious 27620 84 50-75% Grass cover, Fair, HSG D 47990 79 Woods, Fair, HSG D 157860 90 Weighted Average 77610 47.98% Pervious Area 87250 52.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 1: Existing Drainage Area 1 Hydrograph El Runoff ............................ ................ ............................... 1.98 cfs 2 T e ll 24�h 2 -YFZ R i f 11 00 ' Ru ff Ar a 15,81 1)0::s Run ff Vol =6,405 c n e P h 5.................... ....... ° T SO i LL � N=:q 0 U999OU1111111111111111199 �7 U 0 0 1111 1111 1111 1111 Y Y Y U Y Y Y Y U Y U U U U U U U U U U U U U U U U 0 0 1111 11111111 11111111 11111111 Y U Y Y Y Y U 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) 1162525-EX Type 11124-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 12 Summary for Link DP-1: Design Point #1 Inflow Area = 15,860 sf, 52.02% Impervious, Inflow Depth = 4.85" for 25-YR event Inflow = 1.98 cfs @ 12.07 hrs, Volume= 6,405 cf Primary = 1.98 cfs @ 12.07 hrs, Volume= 6,405 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Link DP-1: Design Point#1 Hydrograph �Inflow 1.98 cfs Primary 2 198cfs nfl cnv A e a 6 N u 3 o � LL 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) brim fir[:Zeport 100...........Yea r III II IIt .................... i�S tIIIII II g 6-6 Appendix B:Standard 2 Computations and Supporting Information 1162525-EX Type ///24-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 13 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1: Existing Drainage Area 1 Runoff Area=15,860 sf 52.02% Impervious Runoff Depth=7.40" Tc=5.0 min C N=90 Runoff=2.96 cfs 9,776 cf Link DP-1: Design Point#1 Inflow=2.96 cfs 9,776 cf Primary=2.96 cfs 9,776 cf Total Runoff Area= 15,860 sf Runoff Volume =9,776 cf Average Runoff Depth = 7.40" 47.98% Pervious = 7,610 sf 52.02% Impervious= 8,250 sf 1162525-EX Type 11124-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment 1: Existing Drainage Area 1 Runoff = 2.96 cfs @ 12.07 hrs, Volume= 9,776 cf, Depth= 7.40" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 100-YR Rainfall=8.60" Area (sf) CN Description 87250 98 Impervious 27620 84 50-75% Grass cover, Fair, HSG D 47990 79 Woods, Fair, HSG D 157860 90 Weighted Average 77610 47.98% Pervious Area 87250 52.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tic Subcatchment 1: Existing Drainage Area 1 Hydrograph El Runoff ...........------------------------------............................. .....................----- ......................... 2.96 cfs 3 T e ll 24�h 101) i f 11 0 ' u ff r a 15, 0 s 2 RU..... ou c In oi ep h 0 ' ° T 51 rmrC*N=:9 LL WOM5,4110i 1 0 Q Q Q U rr777rr777r77rr7777r77-rF7F77r77-F Q Q Q U Q U U U U U U U U U U U U U U U U 0 U 9 9 9 9 U 9 9 U U U 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) 1162525-EX Type 11124-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 15 Summary for Link DP-1: Design Point #1 Inflow Area = 15,860 sf, 52.02% Impervious, Inflow Depth = 7.40" for 100-YR event Inflow = 2.96 cfs @ 12.07 hrs, Volume= 9,776 cf Primary = 2.96 cfs @ 12.07 hrs, Volume= 9,776 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Link DP-1: Design Point#1 Hydrograph EM Inflow 2.96 cfs El Primary 3 2.96 cfs nflow A ea 6 ................... ....... .............................. ................................................ N u 3 0 LL 1 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) brim fir I[:Ze ,rt A���llllllllllllia mmuuuu� r uuum uuumuum uumi I uuumum uuum Il,w B-7 Appendix B:Standard 2 Computations and Supporting Information 12 11 Proposed Drainage Are 2 Proposed Drai nage Area P-1 1 DP-1 Proposed Pond 1 13 Design Point#1 Proposed Drainage Area 3 S 4bcat Reach Pond Link Routing Diagram for 1162525-PR Prepared by VHB, Printed 6/29/2022 HydroCAD®10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC 1162525-PR Prepared by VHB Printed 6/29/2022 HydroCAD® 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 3 Area Listing (all nodes) Area CN Description (sq-ft) (subcatchment-numbers) 51070 84 50-75% Grass cover, Fair, HSG D (117 12, 13) 500 96 Gravel surface, HSG D (117 13) 11720 98 Impervious (12, 13) 57030 98 Pavement (11) 31200 98 Roof (11) 340 79 Woods, Fair, HSG D (13) 15,860 93 TOTAL AREA brim fir[:Zeport 2...........Yea r III II IIt .................... �)roposed 6-8 Appendix B:Standard 2 Computations and Supporting Information 1162525-PR Type ///24-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCAD® 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 4 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 11: Proposed Drainage Runoff Area=11,310 sf 72.77% Impervious Runoff Depth=2.64" Tc=5.0 min CN=95 Runoff=0.77 cfs 2,493 cf Subcatchment 12: Proposed Drainage Area Runoff Area=2,555 sf 50.10% Impervious Runoff Depth=2.26" Tc=5.0 min CN=91 Runoff=0.15 cfs 481 cf Subcatchment 13: Proposed Drainage Area Runoff Area=1,995 sf 22.06% Impervious Runoff Depth=1.91" Tc=5.0 min CN=87 Runoff=0.10 cfs 318 cf Pond P-1: Proposed Pond 1 Peak Elev=243.64' Storage=597 cf Inflow=0.87 cfs 2,811 cf Outflow=0.75 cfs 2,434 cf Link DP-1: Design Point#1 Inflow=0.89 cfs 2,915 cf Primary=0.89 cfs 2,915 cf Total Runoff Area= 15,860 sf Runoff Volume = 3,292 cf Average Runoff Depth =2.49" 37.26% Pervious = 5,910 sf 62.74% Impervious= 9,950 sf 1162525-PR Type 11124-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 11: Proposed Drainage Area 1 Runoff = 0.77 cfs @ 12.07 hrs, Volume= 2,493 cf, Depth= 2.64" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2-YR Rainfall=3.20" Area (sf) CN Description 57030 98 Pavement 27710 84 50-75% Grass cover, Fair, HSG D 31200 98 Roof 370 96 Gravel surface, HSG D 117310 95 Weighted Average 37080 27.23% Pervious Area 87230 72.77% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 11: Proposed Drainage Area 1 Hydrograph 0.85 Runoff 0.8 ........................ o.n ots 0.75 ........................... ...... T pe-111.24 :,,h 0.7 0.65 0.6 ......... ............... ................ ...................................... ........................ R o............f A e 11 s 0.55 R off V 1 2 0.5 � N .............. ....... .................................................... --------------- ................................. ..................... 0.45 u e h 4' ........ 0 0.4T 5, LL 0.35 N 9 0.3 0.25 0.2 0.15 0.1 0.05 c 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) 1162525-PR Type 11124-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment 12: Proposed Drainage Area 2 Runoff = 0.15 cfs @ 12.07 hrs, Volume= 481 cf, Depth= 2.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2-YR Rainfall=3.20" Area (sf) CN Description 11280 98 Impervious 1,275 84 50-75% Grass cover, Fair, HSG D 21555 91 Weighted Average 11275 49.90% Pervious Area 17280 50.10% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 12: Proposed Drainage Area 2 Hydrograph 0.17 El Runoff .............. ------------ -------------- 0.16 ................................. o.ts cts 0.15Y -- -----111...24... ..... ..................................... ....................... ............T 0.14 2 0.13FBI f 0.12 n a- S 0.11 ...........................I.... ............... .... � y 0.1 ff-v 0 u pi Ci w = 0.09 ....... ...................... ............... 'U nof f 01�2-12 0 0.08 -------------- 0.07 0.06 0.05 0.04 0.03 0.02 0.01 Q 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) 1162525-PR Type 11124-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 7 Summary for Subcatchment 13: Proposed Drainage Area 3 Runoff = 0.10 cfs @ 12.08 hrs, Volume= 318 cf, Depth= 1.91" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2-YR Rainfall=3.20" Area (sf) CN Description 440 98 Impervious 1,085 84 50-75% Grass cover, Fair, HSG D 340 79 Woods, Fair, HSG D 130 96 Gravel surface, HSG D 17995 87 Weighted Average 17555 77.94% Pervious Area 440 22.06% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 13: Proposed Drainage Area 3 Hydrograph 0.115 El 0.11 Runoff 0.105 0.�0 ots 0.1Tly "I :t 0.095 .......................... 0.09 � 0.085 .................................. ........... ............... 0.08 n a, 0.075 .............. .. ......... ............ ... 0.07 r fl in 0.065 =- 0.06 91 0 0.055 ...... ........ 'Un. TINIAI=11111� LL 0.05 ............. 0.045 0.04 0.035 0.03 .................... ........................... . ............................ 0.025 0.02 0.015 0.01 ................... 0.005 � 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) 1162525-PR Type Ill 24-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 8 Summary for Pond P-1: Proposed Pond 1 I nflow Area = 13,305 sf, 65.16% Impervious, Inflow Depth = 2.54" for 2-YR event Inflow = 0.87 cfs @ 12.07 hrs, Volume= 2,811 cf Outflow = 0.75 cfs @ 12.12 hrs, Volume= 2,434 cf, Atten= 13%, Lag= 2.9 min Primary = 0.75 cfs @ 12.12 hrs, Volume= 2,434 cf Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 243.64' @ 12.12 hrs Surf.Area= 977 sf Storage= 597 cf Plug-Flow detention time= 104.3 min calculated for 2,430 cf(86% of inflow) Center-of-Mass det. time= 45.7 min ( 830.1 - 784.3 ) Volume Invert Avail.Storage Storage Description #1 242.90' 869 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 242.90 645 0 0 243.40 865 378 378 243.90 11100 491 869 Device Routing Invert Outlet Devices #1 Primary 243.40' 2.7' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=0.73 cfs @ 12.12 hrs HW=243.63' (Free Discharge) L1=Broad-Crested Rectangular Weir (Weir Controls 0.73 cfs @ 1.16 fps) 11 62525-PR Type ///24-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCAD@ 10.10-5a s/n 01038 @ 2020 HydroCAD Software Solutions LLC Page 9 Pond P-1: Proposed Pond 1 Hydrograph .................................. ......................................... Inflow . ......................... ....................... 0.95 ............ 0.87 cfs El Primary ............................. ............... ....................................................................................................................... ................ ............. ............. ............ 0.9 ... 0.85 ....... ................................................. .......................... a. ... ... 0.8 ............. ....................... 0.75 cfs ............ .................I .. ....... 0.75 ...................................... S .......... c 0.7 .......... .................. ............... Vc, 0.65 .............. ........................ .T------- ------- ......--------.............................. ........ I................ 0.6 ............................ 00-% 0.55 .................................. .............................- -------- 0.5 .......... ................ o0.45 ............. .................... ...................................................................................................................... .......................................................................................................................I ............................... LL ................0.4 ....................................... ........ 0.35 0.3 ....................... ........................ 0.25 .................... ........................ ............. 0.2 0.15 .................. ............................... .............. ................ ---------- 0.1 0.05 ....................................... 0 111111111111 111111111111 Ill 1111 1111 1111 1111 1111 1111 v v v U U 7�7F7F�rF7F7F7F�rF7F7F7F�FFV7FTIFlr7ilI 11171191IF1117117117111 U 9 9 9 rr7-rr77rr77 U U TT71�]JIF]II�ll�ll�1191111FIlill�illlFm 0 1111 U U U U 1,1,1 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) 1162525-PR Type 11124-hr 2-YR Rainfall=3.20" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 10 Summary for Link DP-1: Design Point #1 Inflow Area = 15,860 sf, 62.74% Impervious, Inflow Depth = 2.21" for 2-YR event Inflow = 0.89 cfs @ 12.11 hrs, Volume= 2,915 cf Primary = 0.89 cfs @ 12.11 hrs, Volume= 2,915 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Link DP-1: Design Point#1 Hydrograph � EM Inflow 0.89 its El Primary 0.89 cfs nflow A ea 6 N u 3 0 .......... .. .......... .......... ........................................................ 0 1111 U U U U U U U U U 0 M M M 111 M M M M u!lll M M T-Tji 0 U U U U U U U U U U U U U U U U 0 0 1111 M M M M U M M M M Ui M 0 0 U U U U U U U U U U U U U7�7F�IF�FFF-T7FW-F'�Jjjj 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) brim fir I[:Ze ,rt 10...........YeaIII S tormIII roposed 6-9 Appendix 6:Standard 2 Computations and Supporting Information 1162525-PR Type ///24-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCAD® 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 11 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 11: Proposed Drainage Runoff Area=11,310 sf 72.77% Impervious Runoff Depth=4.22" Tc=5.0 min CN=95 Runoff=1.19 cfs 3,979 cf Subcatchment 12: Proposed Drainage Area Runoff Area=2,555 sf 50.10% Impervious Runoff Depth=3.79" Tc=5.0 min CN=91 Runoff=0.25 cfs 807 cf Subcatchment 13: Proposed Drainage Area Runoff Area=1,995 sf 22.06% Impervious Runoff Depth=3.38" Tc=5.0 min CN=87 Runoff=0.18 cfs 562 cf Pond P-1: Proposed Pond 1 Peak Elev=243.72' Storage=681 cf Inflow=1.37 cfs 4,541 cf Outflow=1.22 cfs 4,163 cf Link DP-1: Design Point#1 Inflow=1.45 cfs 4,970 cf Primary=1.45 cfs 4,970 cf Total Runoff Area= 15,860 sf Runoff Volume = 5,347 cf Average Runoff Depth =4.05" 37.26% Pervious = 5,910 sf 62.74% Impervious= 9,950 sf 1162525-PR Type 11124-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 12 Summary for Subcatchment 11: Proposed Drainage Area 1 Runoff = 1.19 cfs @ 12.07 hrs, Volume= 3,979 cf, Depth= 4.22" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 10-YR Rainfall=4.80" Area (sf) CN Description 57030 98 Pavement 27710 84 50-75% Grass cover, Fair, HSG D 31200 98 Roof 370 96 Gravel surface, HSG D 117310 95 Weighted Average 37080 27.23% Pervious Area 87230 72.77% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 11: Proposed Drainage Area 1 Hydrograph El Runoff 1.19 cfs T e ll 24�h 4 =Y-Ft R ....................... ................. u ffAr a 11, 0 s Run ffVolu 3, 9 c n epih 2 ' ,° Tc 5 0 i =9 ruo g/s/ 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) 1162525-PR Type 11124-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment 12: Proposed Drainage Area 2 Runoff = 0.25 cfs @ 12.07 hrs, Volume= 807 cf, Depth= 3.79" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 10-YR Rainfall=4.80" Area (sf) CN Description 11280 98 Impervious 1,275 84 50-75% Grass cover, Fair, HSG D 21555 91 Weighted Average 11275 49.90% Pervious Area 17280 50.10% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 12: Proposed Drainage Area 2 Hydrograph 0.28 El Runoff .............. ------------ .............. 0.26 0.25 cfs 7..................... 11124.... 0.24 Y. 0.22 ................. ............. I................ 11 49:,,8 � .. 0.215- ........... no- a- o.1s m 0.16 o U e c w 0.14 un t 3 7 0 � ........ LL 0.12 0.1 0.08 0.06 0.04 0.02 Q a. c 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) 1162525-PR Type 11124-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment 13: Proposed Drainage Area 3 Runoff = 0.18 cfs @ 12.07 hrs, Volume= 562 cf, Depth= 3.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 10-YR Rainfall=4.80" Area (sf) CN Description 440 98 Impervious 1,085 84 50-75% Grass cover, Fair, HSG D 340 79 Woods, Fair, HSG D 130 96 Gravel surface, HSG D 17995 87 Weighted Average 17555 77.94% Pervious Area 440 22.06% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 13: Proposed Drainage Area 3 Hydrograph 0.2 LEI 0.19 Runoff 0.18 cfs 0.18 1 -1...24 TY I 0.17 0.16 ....................... f 42 0.15 0.14 n 951 0.13 � 0.12off 0 U e 62 C 0.11 ........... .............. ........3 0.1 0 � LL 0.09 .............. 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 c c- 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) 1162525-PR Type ///24-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 15 Summary for Pond P-1: Proposed Pond 1 I nflow Area = 13,305 sf, 65.16% Impervious, Inflow Depth = 4.10" for 10-YR event Inflow = 1.37 cfs @ 12.07 hrs, Volume= 4,541 cf Outflow = 1.22 cfs @ 12.11 hrs, Volume= 4,163 cf, Atten= 11%, Lag= 2.6 min Primary = 1.22 cfs @ 12.11 hrs, Volume= 4,163 cf Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 243.72' @ 12.11 hrs Surf.Area= 1,017 sf Storage= 681 cf Plug-Flow detention time= 79.3 min calculated for 4,156 cf(92% of inflow) Center-of-Mass det. time= 37.3 min ( 809.8 - 772.5 ) Volume Invert Avail.Storage Storage Description #1 242.90' 869 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 242.90 645 0 0 243.40 865 378 378 243.90 11100 491 869 Device Routing Invert Outlet Devices #1 Primary 243.40' 2.7' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=1.19 cfs @ 12.11 hrs HW=243.72' (Free Discharge) L1=Broad-Crested Rectangular Weir (Weir Controls 1.19 cfs @ 1.39 fps) 1162525-PR Type 11124-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Pape 16 Pond P-1: Proposed Pond 1 Hydrograph EM Inflow 1.37 cfs El Primary nflow A a 0 1.22 cfs P I = 172 ............. ............. S1 I N 0i u 3 0 . ......... QV�FFVTT VII�11911FIll�ll�ll�11911PI17T-V--TTFF7F7F�FF7FF7F�FF7F7F7F�FF7FIF-9 0 1111 1111 1111 1111 1111 1111 1111 M U M M M U U U U U U U U U U U U U U U U U 0 0 0 1111 1111 1111 1111 1111 1111 1111 1111 1111 v v U U U U U U U U U U U U U U U U U U 0 vill 1111 1111 1111 1111 1111 1111 U M M M U U U U U U U U U U U U U U U U U 0 0 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) 1162525-PR Type 11124-hr 10-YR Rainfall=4.80" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 17 Summary for Link DP-1: Design Point #1 Inflow Area = 15,860 sf, 62.74% Impervious, Inflow Depth = 3.76" for 10-YR event Inflow = 1.45 cfs @ 12.11 hrs, Volume= 4,970 cf Primary = 1.45 cfs @ 12.11 hrs, Volume= 4,970 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Link DP-1: Design Point#1 Hydrograph �Inflow 1.45 cfs El Primary 1.45 cfs nflow A ea , 6 ........... ........................................ . ................... ............................................ N u 3 0 LL w y 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) brim ter[:Zeport 25...........Yea r III II III IIIo p o s e d B-10 Appendix B:Standard 2 Computations and Supporting Information 1162525-PR Type ///24-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCAD® 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 18 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 11: Proposed Drainage Runoff Area=11,310 sf 72.77% Impervious Runoff Depth=5.41" Tc=5.0 min CN=95 Runoff=1.51 cfs 5,100 cf Subcatchment 12: Proposed Drainage Area Runoff Area=2,555 sf 50.10% Impervious Runoff Depth=4.96" Tc=5.0 min C N=91 Runoff=0.32 cfs 1,055 cf Subcatchment 13: Proposed Drainage Area Runoff Area=1,995 sf 22.06% Impervious Runoff Depth=4.52" Tc=5.0 min CN=87 Runoff=0.24 cfs 751 cf Pond P-1: Proposed Pond 1 Peak Elev=243.78' Storage=737 cf Inflow=1.74 cfs 5,851 cf Outflow=1.58 cfs 5,474 cf Link DP-1: Design Point#1 Inflow=1.88 cfs 6,529 cf Primary=1.88 cfs 6,529 cf Total Runoff Area= 15,860 sf Runoff Volume = 6,907 cf Average Runoff Depth = 5.23" 37.26% Pervious = 5,910 sf 62.74% Impervious= 9,950 sf 1162525-PR Type 11124-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 19 Summary for Subcatchment 11: Proposed Drainage Area 1 Runoff = 1.51 cfs @ 12.07 hrs, Volume= 57100 cf, Depth= 5.41" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 25-YR Rainfall=6.00" Area (sf) CN Description 57030 98 Pavement 27710 84 50-75% Grass cover, Fair, HSG D 31200 98 Roof 370 96 Gravel surface, HSG D 117310 95 Weighted Average 37080 27.23% Pervious Area 87230 72.77% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 11: Proposed Drainage Area 1 Hydrograph El Runoff 1.51 cfs T ell 24�h 2 - i f 11 0 ' Ru off Ar a 11,3 OS 1 ! 0 Rui Vol 1 � YI ep h:= Al ° Tc 5.0: i ziz &4 jjpjj1171111F]Jjpjj 0 r7rM17 11 11 =9 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) 1162525-PR Type 11124-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 20 Summary for Subcatchment 12: Proposed Drainage Area 2 Runoff = 0.32 cfs @ 12.07 hrs, Volume= 1,055 cf, Depth= 4.96" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 25-YR Rainfall=6.00" Area (sf) CN Description 11280 98 Impervious 17275 84 50-75% Grass cover, Fair, HSG D 27555 91 Weighted Average 17275 49.90% Pervious Area 17280 50.10% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 12: Proposed Drainage Area 2 Hydrograph 0.36 Runoff 0.34 0.32 cfs 0.32 0.3 F all T 11:= 0' 0.28 0.26 7 0.24 0.22ff-V-.. � ..... C+ 0.2U pth: w 0.18 LL 0.16 T 5 0 i ........................ ................ ........................ ....... 0.14 C N=9 0.12 0.1 0.08 0.06 0.04 0.02 c a 0 _ � c 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) 1162525-PR Type 11124-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 21 Summary for Subcatchment 13: Proposed Drainage Area 3 Runoff = 0.24 cfs @ 12.07 hrs, Volume= 751 cf, Depth= 4.52" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 25-YR Rainfall=6.00" Area (sf) CN Description 440 98 Impervious 1,085 84 50-75% Grass cover, Fair, HSG D 340 79 Woods, Fair, HSG D 130 96 Gravel surface, HSG D 17995 87 Weighted Average 17555 77.94% Pervious Area 440 22.06% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tic Subcatchment 13: Proposed Drainage Area 3 Hydrograph 0.26 El Runoff 0.24 cfs 0.24 T 111...214 0.22 11 0 0.2 0.1$ no f a 9 s ...... ............. H, i 0.16M i ..................... off U &=7,51 C ". 0.14 3 5 It ' ° 0.12 LL 0.1 o.o$ N................. .................................. ------------------ ........ 0.06 0.04 0.02 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) 1162525-PR Type ///24-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 22 Summary for Pond P-1: Proposed Pond 1 nflow Area = 13,305 sf, 65.16% Impervious, Inflow Depth = 5.28" for 25-YR event Inflow = 1.74 cfs @ 12.07 hrs, Volume= 5,851 cf Outflow = 1.58 cfs @ 12.11 hrs, Volume= 5,474 cf, Atten= 10%, Lag= 2.5 min Primary = 1.58 cfs @ 12.11 hrs, Volume= 5,474 cf Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 243.78' @ 12.11 hrs Surf.Area= 1,042 sf Storage= 737 cf Plug-Flow detention time= 68.5 min calculated for 5,474 cf(94% of inflow) Center-of-Mass det. time= 33.2 min ( 799.9 - 766.7 ) Volume Invert Avail.Storage Storage Description #1 242.90' 869 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 242.90 645 0 0 243.40 865 378 378 243.90 11100 491 869 Device Routing Invert Outlet Devices #1 Primary 243.40' 2.7' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=1.54 cfs @ 12.11 hrs HW=243.77' (Free Discharge) L1=Broad-Crested Rectangular Weir (Weir Controls 1.54 cfs @ 1.54 fps) 1162525-PR Type 11124-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Pape 23 Pond P-1: Proposed Pond 1 Hydrograph EM Inflow 1.74orsEl Primary nfl a 0 1.58 cfs 178 or g 37 :c N w u 3 0 LL low 0 Fv�FF1FVVV1�1qjP11 1111 1111 111111111111 vy vUUU UUU,UU Up UU qu up PUP U v U U U U U U U U U U U U U U U U U U 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) 1162525-PR Type 11124-hr 25-YR Rainfall=6.00" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 24 Summary for Link DP-1: Design Point #1 Inflow Area = 15,860 sf, 62.74% Impervious, Inflow Depth = 4.94" for 25-YR event Inflow = 1.88 cfs @ 12.11 hrs, Volume= 6,529 cf Primary = 1.88 cfs @ 12.11 hrs, Volume= 6,529 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Link DP-1: Design Point#1 Hydrograph �Inflow 1.88 its El Primary Z ,$$c`S nflow A ea 5, 6 sf M/ W-10 u o � LL 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) S,tormwater[:Zeport 100...........Year III II IIt .................... ro p o s e d 6-11 Appendix B:Standard 2 Computations and Supporting Information 1162525-PR Type ///24-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCAD® 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 25 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 11: Proposed Drainage Runoff Area=11,310 sf 72.77% Impervious Runoff Depth=8.00" Tc=5.0 min CN=95 Runoff=2.18 cfs 7,539 cf Subcatchment 12: Proposed Drainage Area Runoff Area=2,555 sf 50.10% Impervious Runoff Depth=7.52" Tc=5.0 min CN=91 Runoff=0.48 cfs 1,601 cf Subcatchment 13: Proposed Drainage Area Runoff Area=1,995 sf 22.06% Impervious Runoff Depth=7.03" Tc=5.0 min C N=87 Runoff=0.36 cfs 1,170 cf Pond P-1: Proposed Pond 1 Peak Elev=243.88' Storage=848 cf Inflow=2.54 cfs 8,709 cf Outflow=2.34 cfs 8,331 cf Link DP-1: Design Point#1 Inflow=2.79 cfs 9,932 cf Primary=2.79 cfs 9,932 cf Total Runoff Area= 15,860 sf Runoff Volume = 10,309 cf Average Runoff Depth = 7.80" 37.26% Pervious = 5,910 sf 62.74% Impervious= 9,950 sf 1162525-PR Type 11124-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 26 Summary for Subcatchment 11: Proposed Drainage Area 1 Runoff = 2.18 cfs @ 12.07 hrs, Volume= 7,539 cf, Depth= 8.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 100-YR Rainfall=8.60" Area (sf) CN Description 57030 98 Pavement 27710 84 50-75% Grass cover, Fair, HSG D 31200 98 Roof 370 96 Gravel surface, HSG D 117310 95 Weighted Average 37080 27.23% Pervious Area 87230 72.77% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 11: Proposed Drainage Area 1 Hydrograph El Runoff 2.18 cfs :T e---- - .......... H. 4 ,h z 101 -YFZ Z i faill 0 ' Rup ff Ar a 11 13 0 s u ffVolu 7,15 9 c n ep h 0 ' 3 0T C 51 ............. ......... .0: 1 =9 o N 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) 1162525-PR Type 11124-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 27 Summary for Subcatchment 12: Proposed Drainage Area 2 Runoff = 0.48 cfs @ 12.07 hrs, Volume= 1,601 cf, Depth= 7.52" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 100-YR Rainfall=8.60" Area (sf) CN Description 11280 98 Impervious 17275 84 50-75% Grass cover, Fair, HSG D 27555 91 Weighted Average 17275 49.90% Pervious Area 17280 50.10% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 12: Proposed Drainage Area 2 Hydrograph Runoff 0.5 o.as cfs Twe-A-11-24h ......................................... ......... 0.45 0! FZ Onf 11: 0.4 0' . ......2. -5: .................. .......................................... .......................... 0.35 R ........ -------------- f V I =1 1 c 03 u ........ .................... . .............. ....... f e h 2' ......... ° 0.25 T c 51.0 i ............. ................ ............... 0.2CN*9 ........................ ....... ............... .............. 0.15 ........... 0.1 0.05 c - c 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) 1162525-PR Type 11124-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 28 Summary for Subcatchment 13: Proposed Drainage Area 3 Runoff = 0.36 cfs @ 12.07 hrs, Volume= 1,170 cf, Depth= 7.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 100-YR Rainfall=8.60" Area (sf) CN Description 440 98 Impervious 17085 84 50-75% Grass cover, Fair, HSG D 340 79 Woods, Fair, HSG D 130 96 Gravel surface, HSG D 17995 87 Weighted Average 17555 77.94% Pervious Area 440 22.06% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Minimum Tc Subcatchment 13: Proposed Drainage Area 3 Hydrograph 0.4 El 0.38 Runoff 0.36 cfs 0.36 T 24 :� 0.34 0.32 � 0.3 ............ 0.2$ On,..... ell s V! 0.26 0.24 � 0.22 ..... ............ pt 3 0.2 LL 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 � c c 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) 1162525-PR Type ///24-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 ©2020 HydroCAD Software Solutions LLC Page 29 Summary for Pond P-1: Proposed Pond 1 nflow Area = 13,305 sf, 65.16% Impervious, Inflow Depth = 7.85" for 100-YR event Inflow = 2.54 cfs @ 12.07 hrs, Volume= 8,709 cf Outflow = 2.34 cfs @ 12.11 hrs, Volume= 8,331 cf, Atten= 8%, Lag= 2.3 min Primary = 2.34 cfs @ 12.11 hrs, Volume= 8,331 cf Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 243.88' @ 12.11 hrs Surf.Area= 1,091 sf Storage= 848 cf Plug-Flow detention time= 52.3 min calculated for 8,317 cf(96% of inflow) Center-of-Mass det. time= 27.2 min ( 785.5 - 758.3 ) Volume Invert Avail.Storage Storage Description #1 242.90' 869 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 242.90 645 0 0 243.40 865 378 378 243.90 11100 491 869 Device Routing Invert Outlet Devices #1 Primary 243.40' 2.7' long x 4.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.38 2.54 2.69 2.68 2.67 2.67 2.65 2.66 2.66 2.68 2.72 2.73 2.76 2.79 2.88 3.07 3.32 Primary OutFlow Max=2.30 cfs @ 12.11 hrs HW=243.88' (Free Discharge) L1=Broad-Crested Rectangular Weir (Weir Controls 2.30 cfs @ 1.79 fps) 1162525-PR Type 11124-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Pape 30 Pond P-1: Proposed Pond 1 Hydrograph EM Inflow z.saors Primary nflow Aa 0 2.......... .........34 cfs P.....................................ie I = 3. 8 2 ........... or g 4 c N w u 3 0 LL e C"i 11111% . ........... c 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) 1162525-PR Type 11124-hr 100-YR Rainfall=8.60" Prepared by VHB Printed 6/29/2022 HydroCADO 10.10-5a s/n 01038 O 2020 HydroCAD Software Solutions LLC Page 31 Summary for Link DP-1: Design Point #1 Inflow Area = 15,860 sf, 62.74% Impervious, Inflow Depth = 7.51" for 100-YR event Inflow = 2.79 cfs @ 12.10 hrs, Volume= 9,932 cf Primary = 2.79 cfs @ 12.10 hrs, Volume= 9,932 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Link DP-1: Design Point#1 Hydrograph EM Inflow 3 z.7s its Primary 2.79c`S nfl a 6 —— ------..................................... ——--------------------------- N u 3 0 LL 1 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) Stormwater Report Appendix C: Standard 3 Computations and Supporting Documentation > NRCS Web Soil Survey > Geotechnical Report C-1 Appendix C:Standard 3 Computations and Supporting Documentation brim fir I[:Ze ,rt W6���:) I Su��rvey C-2 Appendix C:Standard 3 Computations and Supporting Documentation Hydrologic Soil Group—Essex County, Massachusetts, Northern Part 0 0 326100 326130 326160 326190 326220 326250 326280 326310 326340 326370 326400 326430 420 40'9"N I .; I \\ I \\ I 420 40'9"N \ \\ mop \ WE- \ \ \\ \ \ \ O MIN \. VC TV,NO or ` Z ""' \\ \ \ w ` \ N \ x, r _ - cal it \\ \ Ilk 2.\`' i -.o. \\...:.. \... \ �\ - ir \\ \\ \ \ \ \ \ \ \ \z Im NwO \\ \ \ \ _ \ \ KA VIIIII \ \ \ _ - \ S o iLNI-a � 3 420 40'2"N a 42 40'2"N 326100 326130 326160 326190 326220 326250 326280 326310 326340 326370 326400 326430 Map Scale:1:1,590 if printed on A landscape(11"x 8.5")sheet. 0 ° Meters N 0 20 40 80 120 Feet 0 50 100 200 300 Map projection:Web Mercator Comer coordinates:WGS84 Edge tics:UTM Zone 19N WGS84 USDA Natural Resources Web Soil Survey 6/13/2022 Conservation Service National Cooperative Soil Survey Page 1 of 4 Hydrologic Soil Group—Essex County, Massachusetts, Northern Part MAP LEGEND MAP INFORMATION Area of Interest(AOI) 13 C The soil surveys that comprise your AOI were mapped at .................................. Area of Interest(AOI) 1:15,800. 13 C/D Soils 13 D Warning:Soil Map may not be valid at this scale. Soil Rating Polygons A 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 A/D Water Features line placement.The maps do not show the small areas of B Streams and Canals contrasting soils that could have been shown at a more detailed scale. Transportation ® B/D Rails Please rely on the bar scale on each map sheet for map 0 C Interstate Highways measurements. 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 A 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. C Soil Survey Area: Essex County, Massachusetts, Northern Part Survey Area Data: Version 17,Sep 2,2021 C/D Soil map units are labeled(as space allows)for map scales D 1:50,000 or larger. Not rated or not available Date(s)aerial images were photographed: Aug 13,2020—Oct Soil Rating Points 18,2020 13 A The orthophoto or other base map on which the soil lines were 13 compiled and digitized probably differs from the background A/D imagery displayed on these maps.As a result,some minor B shifting of map unit boundaries may be evident. ® B/D USDA Natural Resources Web Soil Survey 6/13/2022 Conservation Service National Cooperative Soil Survey Page 2 of 4 Hydrologic Soil Group—Essex County, Massachusetts,Northern Part Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 70A Ridgebury fine sandy D 4.0 38.3% loam,0 to 3 percent slopes 72A Whitman fine sandy D 0.2 2.3% loam,0 to 3 percent slopes 310A Woodbridge fine sandy C/D 6.1 59.4% loam,0 to 3 percent slopes Totals for Area of Interest 10.3 100.0% USDA Natural Resources Web Soil Survey 6/13/2022 Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group—Essex County, Massachusetts,Northern Part Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential)when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential)when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff:None Specified Tie-break Rule: Higher USDA Natural Resources Web Soil Survey 6/13/2022 Conservation Service National Cooperative Soil Survey Page 4 of 4 brim fir I[:Ze ,rt � uuuuuo uumum uuuuol� I Im I�wu I uuu uuum uuu�l a IV�ui I�um� I�i� i C-3 Appendix C:Standard 3 Computations and Supporting Documentation KEVIN M. MARTIN, P.E. KMM GEO'TECHNICAL CONSULTANTS, LLC 7 Marshall Road Hampstead, NH 03841 603-489-5556 (p)/ 603-489-5558 (0/781-718-4084(m) kevinmartinpe-Oad.com MEMORANDUM TO: Richard Gallant Middlesex Islanders, LLC P.O. Box 439 Dunstable MA 01827KEVIN M. MARTIN cc: Mark Belter, P.E. CZ-1 , CIVIC. ProCon, Inc. FROM: Kevin M. Martin, P.E. Geotechnical Engineer DATE: November 16, 2011 RE: GEOTECHNICALSUMMARYREPORT MERRIMACK COLLEGE ATHLETIC FACILITY VOLPE CENTER- PROPOSED BUILDING EXPANSION NORTH ANDOVER, MASSACHUSETTS This memorandum report serves as a geotechnical summary report for the referenced project. The contents of this memorandum are subject to the attached Limitations. SITE & PROJECT DESCRIPTION The project site is located at the Volpe Athletic Center on the campus of Merrimack College in North Andover, MA. Present development includes the Volpe Center with attached wood trailers to the south. The building is surrounded by pavement and landscape areas with tennis courts to the south. The Volpe Center is understood to be supported on a shallow spread footing foundation with a concrete floor slab-on-grade. The FFE of the Volpe Center is noted to be 245.2 ft. Based on review of the Site Plan, (prepared by VHB-August 2011), grades are relatively level being near elevation 23 9-245 ft. Shallow wetlands and woodlands border the site to the east and south. The wetlands to the east(rear of building) includes a man-made interceptor ditch which conveys collected water to more expansive wetlands to the south. Roof gutters and some site drainage appear to discharge to the ditch. The wet areas are delineated near elevation -241-242 ft. Several underground utilities intersect the site. These include storm drainage, water, gas, sewer, electric and telephone. Merrimack College November 16, 2011 North Andover, Massachusetts Page 2 of 9 The project includes building expansion to the Volpe Center with associated site improvements. The building expansion will involve removal of the attached trailers and tennis courts to the south. The expansion is understood to consist of asingle-story, steel and concrete masonry framed structure involving a North& South Addition(see Sketch). It is intended to support the building expansion on a conventional shallow foundation using spread footings and a concrete floor slab-on-grade (no basement). The first floor elevation (FFE) for the North & South Additions are to be 242.2 ft & 245.2 ft respectively. Shallow cuts and fills (_1-2 ft) will be necessary for the North Addition whereas shallow Fill(_1-3 ft)will be necessary for South Addition. The purpose of this study is to review the subgrade conditions and provide a geotechnical evaluation related to the foundation design and construction. SUBSURFACE EXPLORATION PROGRAM Test Borings by KMM The exploration program for the project included twelve (12) test borings throughout the building pad and site. The test borings(B 1 to B 12)were advanced to refusal depths of-11-20 ft utilizing 4'/4 inch continuous flight hollow stem augers. Soil samples were typically retrieved at no greater than 5 ft intervals with a 2 inch diameter split-spoon sampler. Standard Penetration Tests (SPTs)were performed at the sampling intervals in general accordance with ASTM-D1586 (Standard Method for Penetration Test and Split-Barrel Sampling of Soils). Field descriptions and penetration resistance of the soils encountered,observed depth to groundwater,depth to apparent bedrock refusal and other pertinent data are contained on the attached Test Boring Logs. The attached Sketch shows the test bore locations. Explorations by Others We were provided a prior Geotechnical Report prepared by McPhail Associates dated June 2000. This report was completed for a prior expansion to the Volpe Center at that time. Test Bore Logs, Test Pit Logs & Laboratory Test results were reviewed as they pertain to this study. Laboratory Testing Two(2)bulk samples obtained from the auger cuttings were submitted for sieve analyses per ASTM Standards. The samples were obtained from the proposed storm water ponds but should be consistent for the site. Gradation tests from the McPhail report were also reviewed. The test results are attached. SUBSURFACE CONDITIONS The subsurface conditions below a surface Topsoil include shallow Fill,stable Glacial deposits then apparent Bedrock refusal. Merrimack College November 16, 2011 North Andover, Massachusetts Page 3 of 9 Organic laden Topsoil and/or Subsoil were encountered in most areas. There is about -1-2 ft of Topsoil at most locations. The Subsoil, where present, extends about -3-4 ft below grade. The Subsoil consists of a rust brown, loose, loamy, silty Sand or sandy Silt with trace root and organic matter. A buried Topsoil was encountered at B4 at a depth of-4-5 ft. Fill was encountered at many locations to shallow depths of-3-5 ft. Fill was identified at B 1, B4, B8,B9&B 10. For the most part,the fill appears to consist of re-worked glacial till(silty Sand,little gravel) with embedded organic matter. Fill should also be expected around the foundation, intersecting utilities and for general site grading. There were no areas of deep and/or expansive fill identified during this study. Fill also appears to be embanked around the existing building. The parent soils include Glacio-Fluvial deposits underlain by Glacial Till. Both soils have somewhat similar composition which includes a grey-brown, fine to medium Sand with Silt, little to trace gravel. The Glacio-Fluvial soils are generally medium dense whereas the Glacial Till is dense to very dense. The Glacio-Fluvial soils appear more wet and retain more moisture given a looser density. Gradation testing generally indicates a well-graded, fine to medium Sand(50-60%) & Silt (30-40%),trace to little gravel(<10-15%). The fine-grained composition of the glacial soils renders them poor-draining, moisture sensitive and frost susceptible. Test bore refusal,presumably bedrock,was encountered at depths of-9-20 ft below grade. Bedrock is not expected to impact the foundation construction. Bedrock in the area is characteristically hard and of sound quality. Groundwater was encountered in the test holes at depths of-2-5 ft below grade. An observation well was installed in B 12 to monitor fluctuations. Shallow groundwater was also noted in the prior geotechnical study with depths of-2-4 Y2 ft below grade(_3-6 ft below FFE). It should be noted that fluctuations in the level of the groundwater may occur due to variations in rainfall,temperature and other factors differing from the time of the measurements.The site is not expected to drain well with shallow wetlands to the east and south. The shallow groundwater is expected to impact the project. FOUNDATION SUBGRADE RECOMMENDATIONS The subgrade conditions are favorable for supporting the proposed building expansion on a conventional spread footing foundation with a concrete floor slab-on-grade. The organic laden soils (topsoil and subsoil), undocumented fill, loamy soils, intersecting utilities and other questionable materials are not suitable for foundation support and shall be removed from the entire building pad including the Footing Zone of Influence (FZ01). The FZOI is defined as that area extending laterally one foot from the edge of footing then outward and downward at a 1 H:1 V splay. There is about ~2-5 ft of fill and organic laden soils in this regard. Structural Fill necessary to achieve foundation grade should conform to the Specifications (Table 1). Merrimack College November 16, 2011 North Andover, Massachusetts Page 4 of 9 The parent subgrade soils should be exposed in the foundation areas prior to casting the footings or placing structural fill. It is recommended that the parent subgrade soils be proof-rolled with vibratory densification and exhibit stable and compact conditions. The purpose of the proof-rolling is to densify the site soils and identify potential loose or unstable areas which should be removed as necessary. Recommended proof-rolling should involve at least 4-5 passes with a vibratory compactor (minimum 750 pound static weight) operating at peak energy. During the proof rolling process, the subgrade should be observed by an Engineer to identify areas exhibiting weaving or instability. It will be necessary to remove weakened or unstable soils and replace with a Structural Fill. Proof-rolling should not be used when the subgrade is near or below the groundwater table as this may result in soil pumping and instability. The contractor should exercise extra precaution to minimize subgrade disturbance in these wet areas. The groundwater table should be continuously maintained at least one foot below construction grade until the backfilling is complete. A protective base of 3/4-inch minus crushed stone(protected with a geotextile filter fabric) should be placed atop the earthen subgrade if wet conditions are present. The stone base shall extend a minimum -6 inches below and laterally beyond the footing limits. Wet conditions should be expected for the majority of the footings especially for the lower North Addition (FFE=242.2 ft). The stone should be immediately placed atop the undisturbed subgrade then tamped with a plate compactor exhibiting stable conditions. The purpose of the stone base is to protect the wet subgrade, facilitate necessary dewatering and provide a dry/stable base upon which to progress foundation construction. We recommend budgeting stone below the footings given the shallow groundwater and wet site. Proper groundwater control and storm water management are also necessary to maintain site stability. Groundwater and wet conditions are generally more problematic if construction occurs during the wetter winter or spring season. The subgrade should ultimately be stable, dewatered, compact and protected from frost throughout construction. Bearing subgrades that become weakened or disturbed due to wet conditions will be rendered unsuitable for structural support. An Engineer from KMM should be scheduled to review the foundation subgrade conditions and preparation during construction. FOUNDATION DESIGN RECOMMENDATIONS The footings are expected to gain bearing support atop the parent glacial soils and/or compacted structural fill. Footings may be designed using a net allowable bearing capacity of 4 ksf(FS=3). The allowable bearing capacity may be increased a third(1/3) when considering transient loads such as wind or seismic. The bearing capacity is contingent upon the perimeter strip footings and isolated column footings being no less than 2 ft and 3 ft in width respectively. For footings less than 3 ft in lateral dimension,the net allowable bearing capacity should be reduced to one-third and multiplied by the least lateral footing dimension in feet. Foundation settlement should be less than 1 inch with differential settlement less than V2 inch. The settlement should be elastic and occur during construction. Exterior footings shall be provided with at least 4 ft of frost protection. Proper frost protection should be necessary during winter construction. Again,the site soils are frost susceptible and the presence of shallow water furthers the concern with regards to potential heave. Merrimack College November 16, 2011 North Andover, Massachusetts Page 5 of 9 The subsurface conditions were reviewed with respect to seismic criteria set forth in the Massachusetts State Building Code (Eighth Edit). Based on the relative density of the soils and the depth to groundwater, the site is not susceptible to liquefaction in the event of an earthquake (Section 1804.6). Based on interpretation of the Building Code, the Site Classification (Section 9.4.1.2.1) is "C" (Very Dense Soil). Given the poor-draining site soils and shallow groundwater, a perimeter foundation drain is recommended along the foundation. The drain should consist of 4 inch PVC-SDR35 perforated pipe fully encased in at least -6 inches of 3/4-inch stone protected with a filter fabric such as Mirafi 140N or equal. The drain maybe placed atop or adjacent to the footing (not below the footing or within the FZ01). The pipe maybe incorporated into the protective stone base below the footings (with geotextile protection). The pipe should be provided with clean-outs and discharge to a storm drain system not subject to surcharge. The Site Engineer should review the discharge of the foundation drains. Clean-outs should be located at bends and no greater than 150 ft on-center. It is recommended that a backflow preventer be installed at the outlet of the drains to reduce the impact of surcharges. The ground surface immediately adjacent to the foundation should be sloped away from the building to allow for positive drainage. It is also recommended that the surficial materials adjacent to the building be relatively impermeable to reduce the volume of precipitation infiltrating into the subsurface. Such impermeable materials include cement concrete,bituminous concrete or a vegetated silty topsoil. Roof gutters and other storm collection should not be discharged to the foundation drains. It is recommended that a minimum 8-inch base of Clean Granular Fill(Table 1) be placed below the concrete floor slab for moisture and frost control. The gravel base shall be increased to no less than 15 inches for exterior concrete slabs exposed to frost. Special slab base preparation for an ice rink should be reviewed and designed by others. We suspect that frost may be an issue in this regard. A subgrade modulus of200 pci may be used for design of the floor slab. The subgrade modulus may be increased 25 pci for every 2 inch in additional gravel base thickness (250 pci g 12 inch gravel base). A vapor retarder should be used below the floor slab dependent upon the floor treatment. A vapor barrier should be specified by others per ACI Standards. A vapor retarder appears necessary given the shallow groundwater, moisture retentive site soils and public use of the building. Structural fill necessary within and below the foundation should also conform to the attached Specifications (Table 1). The existing fill and glacial soils are not rendered suitable for re-use as Structural Fill. These soils may be used for Common Fill in deep pavement areas or used as Ordinary Fill in non-structural areas. PROTECTION OF EXISTING FOUNDATION It is recommended that where the building expansion adjoins the existing building that the footings be constructed at similar grade to mitigate the overlapping of stresses. The Existing Footing Zone of Influence of the existing foundation should not be encroached or disturbed without review by a Professional Engineer. The Existing Footing Zone of Influence is defined as that area extending laterally one foot from the edge of footing then outward and downward at a 1.5H:1 V splay. Per the Merrimack College November 16, 2011 North Andover, Massachusetts Page 6 of 9 Building Code (Section 1805.5), an imaginary line drawn between the lower edges of adjoining footings shall not have a steeper slope than 25° (21-1:I V) with the horizontal unless the material supporting the higher footing is braced or otherwise retained. It is not expected that the existing foundation will need to be underpinned unless the new footings are deeper. This study did not include verification of the existing foundation via test pits. The prior Geotechnical Report did identify shallow footings(_5-6 ft)in this regard. KMM can provide additional technical assistance if the existing foundation needs to be shored or underpinned. It is expected that conventional concrete pit underpinning will be the most practical. It is recommended that an experienced Contractor be retained for the underpinning. A Technical Submittal should be provided to outline the proposed means and methods to protect the existing building and construct the new underpinning pits. SITE DEVELOPMENT CONSIDERATIONS Bituminous Pavement Structures The flexible pavement recommendations are based on our experience with similar pavement structures and reference to the AASHTO Guide for Design of Pavement Structures. The thickness of each course is a function of the subgrade strength, traffic intensity, design life, drainage, and frost/regional conditions. Based on the foregoing, the following is a summary of our minimum pavement structure recommendations for a 15 year design life: Heavy Duty Light Duty Pavement Course Traffic Conditions Traffic Conditions Bituminous Concrete Top Course, I V2 inch 1 inch MA DPW M3.11.03 Table A Bituminous Concrete Binder Course, 2V2 inch 2 inch MA DPW M3.11.03 Table A Dense Graded Crushed Stone (Base Course) 6 inch 4 inch MA DPW M2.01.7 Gravel Borrow (Sub-Base Course) 12 inch 12 inch MA DPW M1.03.1 TOTAL: 22 inches 19 inches NOTES: Alternative pavement design includes a 16 inch and 14 inch Crushed Gravel Base with no Gravel Sub-Base below the Heavy and Light Duty Pavement Structures respectively. Merrimack College November 16, 2011 North Andover, Massachusetts Page 7 of 9 Heavy duty pavement areas are associated with access drives, entrances, main roadways, etc. whereas light duty pavements are strictly for vehicular parking. The above recommendations are based on a stable,granular subgrade that is free of organic and other weak material The subgrade should be proof rolled with a minimum 10 ton vibratory roller making at least four coverages across the pavement subgrade. Areas exhibiting unstable/weaving conditions should be over-excavated and replaced with compacted structural fill. The subgrade should ultimately be granular, stable and compact being free of organic and weak material. The Crushed Gravel Base Course and Gravel Sub-Base Course should be placed in controlled lifts and compacted to at least 95 percent relative compaction as determined by the Modified Proctor Test (ASTM-D1557). The adequacy of the compaction efforts should be verified by field density testing. Bituminous concrete should be placed in accordance with the MA-DPW Standard Specifications for Bridge and Highway Construction. In particular bituminous concrete should be compacted to at least 95 percent of Marshall density within the specified temperature range. Placement temperatures of bituminous concrete mixes, in general, range between 270 and 310 degrees Fahrenheit. The pavement structure recommendations should not be construed for adequate support of haul roads and other construction traffic. The design and maintenance of such temporary construction roads shall be reviewed by the contractor. A tack coat shall be placed between successive layers of the bituminous concrete. Specifically, a tack coat shall be placed atop the binder course pavement prior to placing the wearing course. The groundwater table should be maintained at least 3 ft below finish pavement grade. Drainage swales and/underdrains may be required in this respect. PERMEABILITY TESTING Bore hole permeability tests were performed in the proposed storm water ponds (B 10 & B 11). Constant head permeability tests were performed at depths of-3-4 ft below grade. The average coefficient of permeability(k) at the respective test holes is as follows: Test Hole Depth Coefficient of Permeability(k) Subgrade B 10 -4 ft 10' cm/sec (0.0015 in/hour) Silty Fill B 10 -5 ft 10' cm/sec (0.0015 in/hour) Glacial Till B 11 -3 ft 5x 10-4 cm/sec (0.07 in/hour) Glacial Till Given the fine-grained composition and density of the Till, we do expect poor-draining soils. We recommend a coefficient of permeability of 10-5 cm/sec (0.0 15 in/hour) for the project. Merrimack College November 16, 2011 North Andover, Massachusetts Page 8 of 9 CONSTRUCTION CONCERNS Subgrade Protection The contractor should be required to maintain a stable-dewatered subgrade for the building foundations and other concerned areas during construction. Subgrade disturbance maybe influenced by excavation methods,moisture,precipitation,groundwater control and construction activities. The site soils (Glacial Fluvial or Till) are considered highly moisture sensitive and will readily become disturbed if exposed to wet conditions and construction activities. The shallow groundwater table further impacts subgrade stability. The contractor should take precautions to reduce subgrade disturbance. Such precautions may include limiting the extent of exposed subgrade if inclement weather is forecast, diverting storm run-off away from construction areas, reducing traffic in sensitive areas,backfilling footings as soon as practicable and maintaining an effective dewatering program. Soils exhibiting weaving or instability should be over-excavated to a more competent bearing subgrade and replaced with a free draining structural fill. The moisture concerns are generally more problematic during the winter/spring season or other periods of inclement weather. A minimum -6 inch base of 3/4-inch minus crushed stone should be used atop the prepared subgrade for protection during construction. The stone base should be protected with a geotextile filter fabric such as Mirafi 140N or equal. The stone base is to protect the site soils, facilitate any necessary dewatering and provide a dry/stable base upon which to progress foundation construction. The protective stone base shall be tamped with a plate compactor and exhibit stable conditions. The stone base should be considered elective and dependent upon the subgrade conditions. The stone base should be considered necessary if wet conditions are present during construction. Wet conditions are expected for the majority of the foundation construction especially the lower North Addition. We recommend budgeting stone below the footings given the shallow groundwater. Proper groundwater control and storm water management will also be necessary to protect the subgrade soils. Subgrades that become weakened or disturbed due to excess moisture or other cause will be rendered unsuitable for structural support. An Engineer from KMM shall be scheduled to review the subgrade conditions and footing subgrade preparation during construction. Groundwater Control Adequate dewatering and storm water management are necessary for maintaining the competency of the site soils. The groundwater table, where encountered, should be continuously maintained at least one foot below construction grade until backfilling is complete. Storm water is also expected to"puddle"within the footing trenches given the low permeability of the site soils. The groundwater or puddled storm water are expected to be controlled with conventional filtered sumps and submersible pumps together with a base of crushed drainage stone. The subgrade should have positive slope towards the temporary sumps. The sumps shall extend at least N 24 inches below construction grade and be protected with filter stone. Soils which become softened and/or disturbed during construction will be rendered unsuitable for structural bearing support. Merrimack College November 16, 2011 North Andover, Massachusetts Page 9 of 9 CONSTRUCTION MONITORING It is recommended that a qualified engineer or representative be retained to review earthwork activities such as the preparation of the foundation bearing subgrade and the placement/compaction of Structural Fill. It is recommended that KMM be retained to provide construction monitoring services. This is to observe compliance with the design concepts presented herein. We trust the contents of this memorandum report are responsive to your needs at this time. Should you have any questions or require additional assistance,please do not hesitate to contact our office. kmm50/KMM 11/NorthAndoverMerrimackCollege.wpd LIMITATIONS Explorations 1. The analyses,recommendations and designs submitted in this report are based in part upon the data obtained from preliminary 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 report. 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 are probably more gradual. For specific information,refer to the individual test pit and/or boring logs. 3. Water level readings have been made in the test pits and/or test borings under conditions stated on the 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 the time the measurements were made. Review 4. It is recommended that this firm be given the opportunity to review final design drawings and specifications to evaluate the appropriate implementation of the recommendations provided herein. 5. In the event that any changes in the nature,design,or location of the proposed areas are planned,the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of the report modified or verified in writing by KMM Geotechnical Consultants,LLC. Construction 6. It is recommended that this firm be retained to provide geotechnical engineering services during the earthwork phases of the work. This is to observe compliance with the design concepts, specifications, and 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 7. This report has been prepared for the exclusive use of Middlesex Islanders, LLC & ProCon Construction,Inc.in accordance with generally accepted soil and foundation engineering practices. No other warranty, expressed or implied, is made. 8. This report has been prepared for this proj ect by KMM Geotechnical Consultants,LLC. This report was completed for preliminary design purposes and may be limited in its scope to complete an accurate bid. Contractors wishing a copy of the report may secure it with the understanding that its scope is limited to preliminary geotechnical design considerations only. TABLE 1 Merrimack College Volpe Center Expansion North Andover, MA Recommended Soil Gradation & Compaction Specifications Clean Granular Fill (Select Gravel Fill) SIEVE SIZE PERCENT PASSING BY WEIGHT 3 inch 100 3/4 inch 60-90 No. 4 20-70 No. 200 2-8 NOTE: For minimum 8-inch base below Concrete Floor Slab-on-Grade For minimum 15-inch base for exterior concrete slabs exposed to frost Shall have less than 12% fines (No. 200 sieve)based on the Sand fraction Compact to at least 95%relative compaction per ASTM D1557 Structural Fill (Gravelly SAND, trace Silt) SIEVE SIZE PERCENT PASSING BY WEIGHT 5 inch 100 3/4 inch 60-100 No. 4 20-80 No. 200 0-12 NOTE: For use as structural load support below the foundations For use as backfill behind unbalanced foundation/retaining walls A 3/4-inch crushed stone maybe used in wet conditions Shall have less than 20% fines (No. 200 sieve)based on the Sand fraction Compact to at least 95%relative compaction per ASTM D1557 TABLE 1 Merrimack College Volpe Center Expansion North Andover, MA Recommended Soil Gradation & Compaction Specifications Common Fill (Silty SAND, little Gravel) SIEVE SIZE PERCENT PASSING BY WEIGHT 6-8 inch 100 3/4 inch 60-100 No. 4 20-85 No. 200 0-25 NOTE: For use as roadway embankment fill is deep pavement areas. Maximum stone size should be 2/s the maximum lift thickness Compact to at least 93%relative compaction per ASTM D1557 Structural Fill placed beneath the foundation should include the Footing Zone of Influence which is defined as that area extending laterally one foot from the edge of the footing then outward and downward at a 1 H:1 V splay. Structural Fill should be placed in loose lifts not exceeding 12 inches for heavy vibratory rollers and 8 inches for vibratory plate compactors. All Structural Fill should be compacted to at least 95 percent of maximum dry density as determined by the Modified Proctor Test (ASTM-D1557). Structural Fill should be compacted within ±3% of optimum moisture content. The adequacy of the compaction efforts should be verified by field density testing which is also a requirement of the Massachusetts State Building Code. ._A U #, yf g - r` x s F a aio Jr z _ 2 e 109 Mgt _ - _ a - —__ e_ F 4=a s¢ r 4 _€ _,, - - -i r ,NOT N �� � -$- ' � Cam$ .--R �r�`-�.;��,f�r=� rr ��� °se - - NOR. F FEa -245 _ . = rR cat i` ;4 r� T 113 - FES 2 E _ _ _ r r ROOF-W fIH _ m . . ,t � # :iF t RAM G 1E Pl:' 242,E -.�-241. - jet', , ' ACR� 243 vl 41. ai loobz a 244,4 [ t , s _ g OVERF 2 ` ` EXISTING my V� `" VOLPE CENTER 019 ' s �, ; fir_ P 2R,19 TA - t4 t _•' Tt" UR �. RAIN GARD „. -Al�, }; 2445 I r 3X r �.4 Q Tc 'E.f BOTTOM 0! Ef 24C5 BC 'r.®• _ 3 _ L `: F 3 rf! l R _ - - fn AMLS" _ { r, 04 E - _amP. ,. � i241( � - - �•$ +� ' 44 POSED , .�. ` ' �. ...�-'�. - - -- SIONT :5 .jam. �o ���++qqrr s�''_$Ps. - - _ -- - 1'F �` -- r l�i�TRR e '�'N _ - 2,45 GRAS s 2445 I�NTER EXPANSION oLi } 180701A�235 I' JJ fP _ - - - - 2 5 = EXIT_ t • m _ a F E E - - g._ A. I Al _ �} ry��g -�. _ _ r - - .-e e , x- 241�- } _ 24 CULLA__ 3 _ _ A VE_ rI - l = s_ ., _ A _ €. . ., - R F t t A_ � F F" a _ et S- 3 a `°: _��P 3 -_° _ ;, 4 f W�NETS THE - 1TY Of THE EX1 TIN STD a i %> SCALE IN FEETIMST lz ES -"c—TKA'c- j&A-&"l low M P., b MAIL TEST BORING LONG SHEET 1 Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-1 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 4, 201 1 Ground Elevation: 243 ft+/- F GROUNDWATER OBSERVATIONS Date Started: October 27,2011 DATE DEPTH CASING STABILIZATION J Date Finished: October 27,2011 10/27/1 5 ft n/a Upon Completion Driller: GG Soil Engineer/Geologist: I ::IF--- Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample Organic Topsoil 1 1 6" 0-1'0" 3-5 1' 1 A 3" 110"-210" 7-9 Brown,fine to medium Sand,little silt(FILL) 2 14" 210"-410" 7-9-9-11 2' Brown,Fine Sand,some silt,trace gravel 5 3 16" 5'0"-7'0" 11-12-12-14 Same,wet (GLACIO-FLUVIAL) 10 4 2" 10'0"-1074" 60/4" 10' Same,with cobbles and boulders. 15 5 13" 15'0"-1770" 13-21-17-22 Grey, fine to medium Sand & Silt, trace gravel, trace clay, wet (TILL) 193 20 Refusal at 19 ft 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET 2 Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-2 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 4, 201 1 Ground Elevation: 242 ft+/- F GROUNDWATER OBSERVATIONS Date Started: October 27,2011 DATE DEPTH CASING STABILIZATION J Date Finished: October 27,2011 10/27/1 5 ft n/a Upon Completion Driller: GG Soil Engineer/Geologist: KM F ::IF--- -IF Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample Organic Topsoil 1 1 6" 0-1'0" 3-5 1' 1 A 6" 110"-210" 5-5 2' Dark Brown,loamy Fine Sand&Silt,trace organics(SUBSOIL) 2 16" 210"-410" 5-5-6-6 Grey-Brown,mottled,fine to medium Sand&Silt,little gravel 5 3 15" 510"-710" 5-7-9-10 Same,wet (GLACIO-FLUVIAL) 9' 10 4 10" 10'0%1270" 16-22-25-26 Brown-Grey, fine to medium Sand & Silt, little gravel, cobbles wet(TILL) 15 5 2" 15'0"-1574" 75/4" Fractured,weathered rock in spoon 17' Refusal at 17 ft Groundwater table at 7'0". 20 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET 3 Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-3 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 4, 201 1 Ground Elevation: 240 ft+/- F GROUNDWATER OBSERVATIONS Date Started: October 28,2011 DATE DEPTH CASING STABILIZATION J Date Finished: October 28,2011 10/28/1 4 ft n/a Upon Completion Driller: GG Soil Engineer/Geologist: KM F ::IF--- -IF Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample Topsoil 1 6" 0-1'0" 2-3 1 1 A 6" 110"-210" 3-4 1' Rust Brown,loamy,Fine Sand&Silt,roots(SUBSOIL) 2 12" 210"-410" 3-4-4-5 Same(SUBSOIL) 4' 5 3 14" 510"-710" 5-7-7-9 Grey-Brown, mottled, fine to medium Sand& Silt, trace gravel, wet (GLACIO-FLUVIAL) 9' 10 4 2" 10VA 0'2" 75/2" Weathered Bedrock 11' Refusal at 11 ft 15 20 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET 4 Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-4 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 4, 201 1 Ground Elevation: 242 ft F GROUNDWATER OBSERVATIONS Date Started: October 27,2011 DATE DEPTH CASING STABILIZATION J Date Finished: October 27,2011 10/27/1 5 ft n/a Upon Completion Driller: GG Soil Engineer/Geologist: I ::IF--- Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample Topsoil 1 5" 0-1'0" 3-5 1 1 A 4" 1'0"-2'0" 4-5 1' Tan,fine to medium Sand,little silt (FILL) 2 13" 210"-410" 4-5-5-6 Same,dry(FILL) 3 8" 410"-510" 2-2 4' Black Organic Silt(TOPSOIL) 5 4 13" 510"-710" 11-17-20-21 5' Grey,fine to medium Sand,some gravel,little silt,cobbles,wet (TILL) 10 5 16" 10'0%1270" 12-24-24-27 Brown,fine to medium Sand&Silt,trace gravel,wet(TILL) 13' 15 6 15'0"-15'4" 75/4" Weathered Bedrock 17' Refusal at 17 ft 20 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET s Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-5 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 4, 201 1 Ground Elevation: 242 ft F GROUNDWATER OBSERVATIONS Date Started: October 27,2011 DATE DEPTH CASING STABILIZATION J Date Finished: October 27,2011 10/27/1 5 ft n/a Upon Completion Driller: GG Soil Engineer/Geologist: I ::IF--- Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample Topsoil 1 6" 0-1'0" 3-3 1' 1 1 A 7" 110"-210" 3-4 Rust Brown,loamy,Fine Sand&Silt(SUBSOIL) 2 12" 210"-410" 4-5-5-6 Rust Brown,Fine Sand&Silt,roots(SUBSOIL) 4' 5 3 8" 510"-612" 9-17-60/2" Brown, mottled, fine to medium Sand & Silt, little gravel, cobbles 10 4 16" 10'0%1270" 13-20-20-24 Same,wet(TILL) 15' 15 5 2" 15'0"-15'2" 75/2" Grey,weathered,fractured rock 17'6" Refusal at 17'6" 20 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 301' I TEST BORING LONG SHEET 6 Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-6 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 8, 201 1 Ground Elevation: 242 ft+/- F GROUNDWATER OBSERVATIONS I Date Started: November 8,2011 DATE DEPTH CASING STABILIZATION J Date Finished: November 8,2011 11/8/11 6 ft n/a Upon Completion Driller: GG 11/8/11 3 ft n/a 2 hours Soil Engineer/Geologist: Kevin Martin 1 11/8/11 JF2ft __]F—n/a 4 hrs Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample Dark Brown,Organic Silt,roots(TOPSOIL) 1 1 17" 0-210" 2-2-2-2 2' 2 12" 210"-410" 4-8-11-11 Grey-Brown, mottled, fine to medium Sand, some silt, little 5' gravel,wet (GLACIO-FLUVIAL) 5 3 11" 510"-710" 9-14-16-17 4 13" 710"-910" 12-20-20-20 Grey-Brown mottled fine to medium Sand and/some Silt' little gravel,wet(TILL) 10 5 16" 10'0"-12'0" 10-19-21-22 Grey-Brown, fine to medium Sand&Silt, trace gravel, cobbles, wet 15 6 14" 15'0"-1673" 27-40-60/3" Same (GLACIAL TILL) 18' 20 Refusal at 18 ft 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET 7 Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-7 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 4, 201 1 Ground Elevation: 243 ft F GROUNDWATER OBSERVATIONS Date Started: October 27,2011 DATE DEPTH CASING STABILIZATION J Date Finished: October 27,2011 10/27/1 5 ft n/a Upon Completion Driller: GG Soil Engineer/Geologist: KM F ::IF--- -IF Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample 1 1 16" 0"-2'0" 3-4-5-5 Topsoil/Subsoil (TOPSOIL/SUBSOIL) 2 3" 210"-310" 4-4 Dark Brown,loamy,silty Sand,trace organics 2A 5" 310"-410" 4-6 3' 5 3 17" 510"-710" 6-7-9-11 Grey-Brown,mottled,Fine Sand&Silt,trace gravel,wet (GLACIO-FUVIAL) 10 4 0" 10'0%1270" 15-20-20-21 10' No recovery 15 5 14" 15'0%17'0" 19-23-30-30 Grey-Brown, fine to medium Sand& Silt, little gravel, cobbles, wet(TILL) 18'6" Refusal at 18'6" 20 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET 8 Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-8 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 4, 201 1 Ground Elevation: 243 ft F GROUNDWATER OBSERVATIONS Date Started: October 28,2011 DATE DEPTH CASING STABILIZATION J Date Finished: October 28,2011 10/28/1 5 ft n/a Upon Completion Driller: GG Soil Engineer/Geologist: KM F ::IF--- -IF Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample Topsoil 1 17" 0"-2'0" 3-4-4-4 1' 1 2 3" 210"-410" 4-4-4-6 Dark Brown, loamy, silty Sand, little gravel, trace organic (FILL) 5' 5 3 17" 510"-710" 7-11-10-10 Grey-Brown,mottled,Fine Sand&Silt,trace gravel,wet (GLACIO-FLUVIAL) 10 4 18" 10'0%1270" 10-10-10-10 Brown,fine to medium Sand&Silt,trace gravel,wet 14' 15 5 18" 15'0%17'0" 20-20-25-25 Brown,fine to medium Sand&Silt,little gravel,cobbles,wet (TILL) 20 6 3" 20'0"-2053" 60/3" Weathered Rock 20'3" Refusal at 20'3" 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET 9 Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-9 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 4, 201 1 Ground Elevation: 243 ft F GROUNDWATER OBSERVATIONS Date Started: October 28,2011 DATE DEPTH CASING STABILIZATION J Date Finished: October 28,2011 10/28/1 2 ft n/a Upon Completion Driller: GG Soil Engineer/Geologist: KM F ::IF--- -IF Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample Topsoil,wet 1 1 16" 0"-2'0" 3-5-5-4 2 6" 210"-310" 2-2 3' Grey-Brown, fine to medium Sand, some silt, little gravel, trace 2A 8" 3'0"-4'0" 5-7 organics,wet(FILL) 5 3 12" 5'0"-7'0" 7-10-11-11 5' Grey,Fine Sand&Silt,trace gravel,wet 4 14" 710"-910" 27-30-17-22 Brown,mottled,Fine Sand&Silt,little gravel(TILL) 10 5 4" 10'0"-1054" 60/4" 10' 11' Weathered,fractured Rock Refusal at 11 ft 15 20 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET 10 Corp.Soil Exploration Volpe Center Expansion eotec nical Drilling BORING B-10 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 4, 201 1 Ground Elevation: 243 ft F GROUNDWATER OBSERVATIONS Date Started: October 28,2011 DATE DEPTH CASING STABILIZATION J Date Finished: October 28,2011 10/28/1 4 ft n/a Upon Completion Driller: GG Soil Engineer/Geologist: KM F ::IF----]F- Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample 1 1 14" 1'0"-350" 5-7-9-9 Brown,fine to medium Sand&Gravel,little silt(FILL) 3' 2 17" 350"-550" 6-7-6-7 Grey,mottled,Fine Sand&clayey Silt,trace gravel(FILL) 5' 5 3 14" 550"-710" 19-20-17-15 Brown-Grey,mottled,Fine Sand&Silt,trace gravel,wet 10 4 16 1005)-120 13-15-15-18 Brown,fine to medium Sand,some silt,little gravel,wet 15 5 8" 15'0"-15'10'7 27-60/4" Grey,Fine Sand&Silt,little gravel,cobbles,wet(TILL) 17'6" Refusal at 17'6" 20 Bore Hole Permeability Tests g 4 ft&5 ft 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET I I Corp.Soil Exploration Volpe Center Expansion Geotechnical Drilling BORING B-I I Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 8, 201 1 Ground Elevation: 238 ft F GROUNDWATER OBSERVATIONS I Date Started: November 8,2011 DATE DEPTH CASING STABILIZATION J Date Finished: November 8,2011 11/8/11 2 ft n/a Upon Completion Driller: GG 1 1 Soil Engineer/Geologist: Kevin Martin ::IF-- -IF Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample 1 1 15" 0-2'0" 2-3-3-3 Dark Brown,Organic Silt w/roots(TOPSOIL) 2' 2 14" 210"-410" 6-10-11-11 Grey-Brown, mottled, fine to medium Sand& Silt, little gravel, wet (GLACIAL) 5 3 18" 510"-710" 12-30-27-26 Same 4 15" 7'0"-910" 13-21-27-27 Same 10 5 Y 10VI-1079" 26-75/3" Same 12' Refusal at 12 ft 15 Bore Hole Permeability Test @ 3 ft 20 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I TEST BORING LONG SHEET 12 Corp.Soil Exploration Volpe Center Expansion Geotechnical Drilling BORING B-12 Groundwater Monitor Well Site: Merrimack College 148 Pioneer Drive Leominster A 153 North Andover,MA PROJECT NO. 11-1033 978 840-031 DATE: November 8, 201 1 Ground Elevation: 240 ft+/- F GROUNDWATER OBSERVATIONS I Date Started: November 8,2011 DATE DEPTH CASING STABILIZATION J Date Finished: November 8,2011 11/8/11 3 ft n/a Upon Completion Driller: GG 1 1 Soil Engineer/Geologist: Kevin Martin ::IF-- -IF Depth Casing Sample Visual Identification Ft. I bl/ft I No. Pen/Rec Depth Blows/6" Strata of Soil and/or Rock Sample 1 15" 0-2'0" 2-3-3-4 Dark Brown,Organic Silt w/roots,wet(TOPSOIL) 1 2 4" 210"-316" 3-3-4 2A 4" 3'6"-4'0" 12 3'6" Dark Brown,loamy,silty Sand,little gravel,wet(SUBSOIL) 476" 5 3 12" 510"-710" 10-12-14-16 Brown, fine to medium Sand, some silt, little gravel, cobbles, 4 15" 7'0"-9'0" 18-20-18-18 wet (GLACIAL) 10 End of boring at 9 ft Observation Well installed to 5 ft 15 20 25 30 35 Notes: Hollow Stem Auger Size-4-1/4" I Cohesionless: 0-4 V.Loose, 4-10 Loose, I Trace 0 to 10% I CASING SAMPLE CORE TYPE I I 10-30 M Dense, 30-50 Dense, 50+V I Little 10 to 20% I ID SIZE(IN) SS I I Cohesive: 0-2 V Soft, 2-4 Soft, 4-8 M I Some 20 to 35% I HAMMER WGT(LB) 140 lb. I 18-15 Stiff, 15-30 V.Stiff, 30+Hard. I And 35%to 50% I HAMMER FALL(IN) 30" I - GRAIN SIZE DISTRIBUTION GRAPH-AGGREGATE GRADATION CHART 4 PROJECT - -- e DATE 'Merrimack College-Volpe Center Expansion -North Andover,MA November 201 SIEVE ANALYSIS-US STANDARD SIEVE SIZES �. (Inches)SIZE SIEVE NUMBER HYDROMETER ANALYSIS 2 1 112 1/4 8 16 30 50 80 140 'NTi iQl�t 90 10 8 - _� - - 20 - - - - - - 30 z - H CA 60 40 50 - 50 _TF- 40 - 60 V4 30 70 - - 80 10 - - - 90 100 GRAIN SIZE IN MILLIMETERS EXCAVATION NUMBER SAMPLE DUMBER LL PI! PI Cu CcSOIL DESCRIPTION REMARKS CLASSIFICATION II SCSI 10( - ft) ssilty Sand_little gravel(FILL) silty Sand,little gravel TILL) SM t*j B I I P-5 ft) 3. TECHNICIAN (Signature) - 4. PLOTTED B (Signature) - s CHECKED 8Y (Signature) - -Kevin actin,P.E. DD FORM 1207, DEC 1999 PREVIOUS EDITION IS OBSOLETE. Adobe Professional 7.0 M.I.T. PROJECT GRAJN SIZE Size f opening, finches U.S.S. Sieve meshes/inch 6" 3" 1 Y 4 10 20 40 60 100 200 SAMPLE100 1T I 111 T1 I I go ,%.k LMEND BOREHOLE 80 ;S4 0 TF-G 1 5-4 - 29.0 70 rn 60 -Lj'IN*\ Lu 9-7 50 00 ui 1011101 01110� 30 20 10 It fill 1 10 1.0 - .1 0.01 0.001 0. 01 - SIZE,GRAIN COB13LE COARSE MEDIUMFINE COARSE MEDIUM NSILT SIZE CLAY SIZE I - GRAVEL f SAND I I GRAINED i m Dui 7i y, ASSOCIATESANC. 6 FOUNDATION ENGINEERING REPORT PROPOSED ADDITIONS AND RENOVATIONS TO THE VOLPE ATHLETIC CENTER NORTH ANDOVER MASSACHUSETTS ire for v. Merrimack College 4 I June 27, 2000 Project No. 3649 a rt a / ��Ur 1J Y/,f i flip iHi1 fimt, N�ymit�l 1 %O rrur frw Wlro I J�xr V f � I t AD )r.D' ATES INC. June27, 2 e technica un ers Merrimack College .315 Turnpike Street North Andover,, MA 0118,45, Attention: Mr. Davld' K. Breen Reference, Proposed se � M tom �s and Renovations, to the �" 1p thlet c center Merrimack college; North Andover, Massachusetts Foundation Engineering Report p Gentlemen This letter report presents the results of our subsurface *Investigation and foundation design study for the proposed additions and renovations to the Volpe, Athletic Center located on the Merrimack, College campus in North Andoveirt Massachusetts. Refer, to the Prci ct Location, Plan, Figure for the general site locus. k The subsurface investigation was, conducted and the foundation engineering services performed in accordance with our proposalfor geotechnical engineering services Fated March 113, 20,00 and the subsequent authorization of Mr. David Breen of Merrimack College on March 13, 2000. These services are subject to the, limitations contained in Appendix A. ' E ore and Sc2Re The purpose of the subsurface investigation is to define the subsurface soil and groundwater cnditiions, at the site, as they, rebate to foundation deslgn, and construction and, based on, this, information, to provide recommendations for economical foundation design and construction for the w proposed addition and renovations to the Volpe Athletic center, Foundation design includes foundation support ofthe proposed addition and its lowest levlel slab,,,, treatment of the ,lowest level slab in consideration of groundwater, and seismic design considera- tions In accordance with the provisions of the Massachusetts Mate Building Code., Foundation construction considerations are also addressed herein.. J 0 ► callable Information Information ,provided to McPhail Associates, Inc. by the Project Architect, Sasaki Associates,, Inc. ed a � c�al topographicaianreaneyerr�Merrimack, n �een c nai � "ces of Andover, Massachusetts dated June 6, 2000 and a 100-scale sketchy plan of proposed additions s and soil boring locations prepared by, Sasaki Associates, Inc. and dated March 3, 2000. 30 Norfolktreat Cambridge, ss s 2 - 6 17/86814 8 - 23, x IID iTAir Merrimack College ASSOCIATES,INC. ,June 27, 2000 Geo ech ical Engineer Page 2 r xIstinc Conditions The project site is located on the south side of Salem Turnpike Route 114), just west of its intersection with Route 125 in forth Andover, Massachusetts. The western portion of the existing building is an elevated 1-story structure that consists of an ice rink with locker room space. The eastern portion of the existing building is understood to consist of two-story structure which contains office and ticket space. The lowest level slab of the existing building is at Elevation +246.0 which is approximately coincident with the existing exterior grade adjacent to the building. The site of the proposed add ion is primarily landscaped area. The existing ground surface within the area of the proposed addition north of the existing building is relatively level at approximate M Elevation +246. The ground surface slopes downward away from the existing building along its western and southern portions from about Elevation +246 at the existing building to approximate Elevations +242 and +240 along the western and southern perimeters of the proposed addition, respectively; Elevations as noted herein are referenced to the Project Datum which is understood to be the National Geodetic vertical Datum lv . Proposed Additions and Renovations The proposed development is understood to include the renovation of existing Volpe Center ice rink and additions to the northern, western and southern portions of the existing VolpeCenter ice rink. The renovations to the ice rink include replacement of the ice rink slab and construction of new precast arena seating. The addition is understood to consist of a two-story steel frame structure occupying an approximate 25,000 square fagot plan area along the western portion of the existing building. No occupied below-grade space is proposed an the lowest level slab is understood to be at the existing ground surface elevation across the building site. Further, it i understood that the design of the proposed `ice rink slab will be performed by others and, thus, i excluded from the scope of this report. Investigation Procedures n March 22, 2000, three 3 soil borings and seven test pits were completed at the site for the purpose of assessing the subsurface soil ,and groundwater conditions. The test borings ,and test pits were performed by Carr-Dee Corp. of Medford, Massachusetts and Lincoln Tree and ,landscape of Acton, Massachusetts, respectively, under contract to McPhail Associates, Inc. Ap- proximate soil boring and test pit locations are as indicated on the enclosed Figure 2 which is based on the above referenced topographic site plan. The subsurface explorations were ,monitored by personnel of McPhail Associates, Inc. who prepared field bogs, obtained and visually classified soil samples, monitored groundwater conditions In the open boreholes, test pits and observation wells, made minor relocations of the explorations, and determined the depths of explorations based upon the actual subsurface conditions en- countered. The existing around surface elevation at each exploration location was determined by a rti n, 1 H/,i i J ° / fG�✓/ pi r �I IN 1 IMerrir� w�ck College�SSOC TE � N�� one 2,71,, 20010 Geotechnical Engineers level survey performed by McPhail Associates, Inc. utilizing vertical control points indicated on the referenced topographic site plan. The soil borings, were advanced by a truck. anted drill rig utilizing the hollow, stem auger drilling t ec,hnie Standard l�'enetratl!on� !ests were conducted in accordance the standard proved urea outlined in Ash 5 6. Soil samples were generally retrieved at 5-foot intervals by driving a standard 2.0-inch, O.D. split-spoon sampler into the soil with a 40-pound hammer falling 3 - inches, Soil was retrieved from the .sampler and visually classified based on texture, coder, and material content. The number of bless required to drive the split-spoon In -inch increments was recorded during the sampling. The sum of the blows for the second and gird increment is referred to as the Standard Penetration Resistance (N-value). The N-value provides a measure of daensit ' for granularl materials such as sand and the consistency of fine-grained materials such as, siilt ot, clay. k The soil borings were terminated in glacial till deposits at a depths ranging from 12.5 to 20.8 feet below the existir ground surface. Observation wells were installed In completed boreholes and -3., Logs of boreholes through ►-3 prepared by Carr-Dee Corp. and Groundwater Monitoring Reports for observation wells B-1 and -3 are presented in Appendix The test pits were excavrated, utillizing a, Case 0 backhoe., 'The test plits were terminated in, the glacial till deposit at depths, ranging from 6 tol 9.3 feet Ibeiow the existing ground surface. logs of test pits TP- through Tl -7 are resented in perduB. Laboratory Testing At the completion of the field work, the soil samples were transported to our laboratory for more detalled classificatio,nP analyses and testing. "'he laboratory testing consisted of sieve analyses to obtain represent tive drain size distributions of samples of the hilll and glacilial till deposits, laboratory test procedures were in general accordance with applicable ASTNI Standards and/or "Soil Testing for Engineers", ' y T. . Lambe. Results of the testing are presented on Figures and 4. Subsurface Conditions , detailed descriptionof thesubsurface sibs ace conditions enolo ntered within each of the three 3 borings and, seven, 7) test, pies, is presented on the enclosed soil boring and test pit logs, contained in Appendix B. The following is a discussion of the generalized subsurface conditions across the site which are inferred primarily from the borings and teat pits, but also from our knowledge ledge of geology f the local area and from our experience at geologically similar sites. The explorations indicate that the ground surface is generally underlain by an approximate o _ to �2. -foot thickness of topsoil,, "here encountered the topsoil deposit consists of loose brown sandy silt ith varying amounts of organics., Topsoil 'was, not" encountered in test pit, TP-7 and soil a Al INV3. a 1„nf..mli0wa�'iw,a„G1 uar ;wfllrt /i Uf i, iQJfa m, ,ryrm � f„ 1 r„ l r , i AS"'OCIATES Merrimack College 0 JNC. June 27, 2000 Geotechnical Engineers Page boring 13-3 located in the northeast corner of the proposed additions,, or boring -2 which was located inn a, parking lot. Underlyingthe topsoil deposit, the explorations s typically encountered a fill deposit. The fill deposit varies from a compact dark brown well graded mixture of silt sand and gravel, to a dense brown ,sand and gravel with trace siit., The fill deposit,, a so, Included variable amounts,ts, of organics, brick and other debris. Where encountered, the thickness of the fill deposit was obs r eld to vary, from 1.0 to 5 feet, Grain size distributions of typical samples of the fill deposit are presented on OF Figure 3. The fill, deposit as not encountered in test it T -5. Directly underlying the topsoil, test pit TP.5 encountered an approximate 1. -foot thickness of subsoil. The subsoil consists of loose silty sand with varying amounts nts of organics. Beneath the fill and/or subsoil, a dense to very dense brown glacial till deposit was encoluntered, The glacial till deposit generally consists of a well-graded ixturra of silt, sand and gravel with occasional cobbles and boulders. The top of the glacial till was present at depths ranging from 1.5 to 6.51 Beet below thila existing ground surface. Grain size, distribution curves, of typical samples, of the glacial till deposit are presented' 'in Figure 4. To document the configuration of the existing structure, test pits " P-4, T P 6 and T P 7 were oompliotod iirnmiediate4y adjacent to the, western, and northern foundation alls t hat will abut th e proposed addition. Test pit, T -4, Tp- and T - encountered a, spread' footing foundation system bearing on the, natural glacial till deposit located at depths ranging from 5.2 to 6.5 feet below ,the existing ground surface. Groundwater ter was observed �in the completed borehMolea and tort, pits at depths rangingfrom 2.0 to 4.5 feet, below the existing ground surface. 'The stabilized groundwater level in observation walls -0B-1 and -3 ranged from, Elevation +239.9 to +242.9. It is anticipated that future, groundwater levels across the project site, y, vary, f�rorri those reported herein based on, such factors as normal sea o a,l changes, runoff, during or following peri rods of heavy precipitation, and alterations to existing drainage patterns.. Foundatlon Des R��oomme d�ations fi ased on our currant understanding of the scope of the proposed project and the anticipated subsurface conditions as, discussed above!, we recommend that foundation support for the proposed addition and renovations to the Volpe Athletic Center be, provided by conventional spread, footings bearing directly on the undisturbed glacial till deposit or on compacted structural fill placed directly over the glacial till deposit, All existing topsoil, fill and subsoil should be stripped in its entirety frolmi the proposed building footprint. All .spread footings should be proportioned utilizing a maximum design bearing pressure of 3. , tons per ,square foot and a minimum footing widths of 2.5 feat. All bearing surrfaces adjacent to tr fyP y r ll r inrJ/)V O// ru�1�SNw+-ss%Nk i,l.:r✓,'!, � ,,,. ail �„ ASSOCIATESINC. Merrimack College June 27, 2000 eoltechn c�a1 Engineers Page 5 unheated areas should he provided with a minimum 4-foot thickness of soil cover as frost Protection. Foundations adjacent to heated areas should be located such that the top of the foundati concrete is least inches bellow, underside the slel -on rade 11 ur dations should be located such that they are below a theoretical line drawn upward and outward at 2 to (horizontal to vertical) from the bottom exterior edge of all adjacent footings, structures and utilities. 'Where required, structural fill; placed for support of foundations should' extend laterally beyond' the edge of footings a distance equal to the depth of fill plus 2 feet. the structural fill should be placed directly on the ;surface of the undisturbed natural glacial till deposit after stripping of the w to, soli, fill and subsoil., It is recommended that the lowest level slab of the proposed building be designed as are economi- cal slab-on-grade immediately underlain by a polyethylene vapor barrier spread over a mini urr - Inch thickness of' compacted gravel fill., w Given that the slab in the proposed addition will he located at or, above the adjacent exterior asp finished grade, a derslah and perimeter dra,iris are not considered necessary for the proposed building a ditior and rink seating foundations,,., However, the ini hied giround surface adjacent t tol the addition, should he pitched away from the structure. �r All structural fill placed within the footprint of the proposed building for support of they foundations an floor, sia should ble placed in lifts having a compacted thiCkneas, of' inche�s, and be compacted to a minimum, of 95 percent of fts maximum um modified Proctor dry density. structural fill " should consist of a ell graded natural sand and gravel containing less than 8 percent passing the No. 200 sieve. Backfilled below grade walls receiving lateral support at the top and bottom i.e. restrained walls) should be designed for a lateral earth pressure corresponding to an equivalent flub density of 60 ,pounds per cubic foot., *ro thus value must be addedthe pressures attributable to earthquake forces per, Section 11612.4.9 of the Code. Lateral forces can be considered to be transmitted from the structure to the bearing strata by passive pressure against the perimeter foundation walls, utilizing an equivalent fluid density of 1,20 pounds per, cubic foot providing that the foundationall's are 'esigne ' to resist these pressures. Lateral force can also be considered to he transmitted from the structure to the soil by friction on the base of footings using a frictional coefficient of 0.50, to which a factor of safety of 1.5 should w e, applied. Seismic Cons Ide rations, rn For purposes of determining the total, lateral seismic force, or base shear for earthquake design, the site is considered to have a s, soil-profile type as defined by section 1612.4.2 of the Massachusetts State Building code. Therefore, the site coefficient "S" for this site should be .0. a f r r✓r ^ r,n// // / emla i/ioruf `u(nm(/r, Nc, r° In IT I S Su"C I AT E S Merrimac! C l!e e June 2T 2000 Geot chnical �ng�iineers Page, Further, the bearing stratum is not considered to be subject to liquefaction during the design earthquake based on the criterion of Section 180 .3 of the State Building Code. Foundation or s rue"l rt Consildespaflons The primary foundation construction considerations include the preparation of foundation bearing surfaces and construction deatering. To rninimi .e d'isturbance of the foundation hearing surface, ft. 'is recomrnended that the finial excavation of all bearing surfaces be performed utilizing excavating equipment which is fitted with a smoothy edged bucket. Further, the glacial till subgrade across the Site is considered to be susceptible to disturbance in the resenco of water. Therefore, all excavated subgrade, should he immediate lacernent of a Inch concrete mud mat or with a 4-inch thicknesso r�to with the �� ���� li f compacted finch crushed, stone to prevent disturbance of the su�bglrade during subsequent corm ng operations, Based on the groundwater levels observed during the subsurface Investigation, the excavation to the top of the glacial till deposit for footings and associated with, the removal of all existing top fill an,d subsotl is expectedto be , erfoirm,ed to or, slightly below, the, groundwater level. Gwen that the depth of excavation below the groundwater is expected to be relatively shallow, dewfaterin g" by conventional summing in conjunction with strategic locations of drainage trenches should be sufficient to control groundwater. Interception of surfacewater and groundwater by, means of trenching and grading of the excavated, areas is considered necessary not only for the purposes of footing su grade preparation but also in consideration of maintaining a trafficable suhgrade on which construction equipment can operate. Even with Proper control of both surface water and groundwater,, R is likely that, during wet eatherf off.*site free-draining gravel and/or crushed stone will be required to maintain trafficability for construction equi m,lent. Figs oasts Work, remaining to be completed by McPhail Associates, Inc.. includes providing deign assistance to the design team during, the final design, phase of this project. Thee purpose, of this involvernent is to review the structural foundation drawings and foundation notes for conformance with the recommendations herein, and to generate or review the earthwork specification section for inclusion into the Contract Documents for construction. It is., recommended that. cPhaif Associates, be, retained during construction, to observe the final preparation of the foundation bearing surfaces and to rnon'tor plat rrnent and compaction of structural fill in accordance with the provisions of the State Building Code. Our involvement during the construction phase of the work should minimize costly delays due to unanticipated field problems since our field engineer, would be under the direct supervision of our, project manger who duo J 9 ur9 w r f oR,a, ✓jm m, i ASSOCIATESJNC 0 00 311 GeotechniCal Engineers Page wasr �uw��l fir the subsurface investigationand foundation design ecom en tions doc - mented herein., We! trust that thole, ablove is suifficentfor your, present requirernents. Shild you have an, questions, coIncer in,g the recommendations, resient d! he a n,, pleas,le calf us,. f Very truly yours, r, `, INC, P Mar M. Demia ee, �I P.E. Enclosures 649 -LRE �MMD/tc I� l r V I G m wr �. N� til u I ,!r I r it `I , r VI I !W I �r I} I I V Y wl� rY�I" 1 r I I� I6 I dur I IN M� VI;i I I FIGUNL '�qpl r may, I� Ilk °I(' w,w „�, �,ir.. "M W,,O 1 �e M ry yyp I'i I / l v rpB� �y y�F►j� 4 o III I! w � ,, ! � n i "� .`5 �+1�` �� I II j' r I� I Y N 4i 1 1 A.. I N I IIi , x C 6 u'4 k i ( b r A o I P m �r R P t I I r0 40 / �u M DIY, r p' v jol✓ i 40, a r N 6 �� e u � I I� k I I Ah � w � �r I� � yr r... ",. '"' ,.� �� ��' � µJWW°.'. ..,n, n✓�"' Ire �. ya,,,, '�*,� � ,N .,�' � �amw"r�"M", IMN�;"��r",N "4 , r� l�, ��e'' � d NNl � ,.;'r,%. �Nl t� �""�,,,,,wrr, ,✓rl� �i��Mp ti,rrr�:ww."*�ry� �":M'�, •4 ^rrM„ "'�,w.� .� '�w. y� "��I 1 M�a"'Nv. � � n Ya �m 1 �>v I .. I �; �„ i wu f l �, I. '$ ""� � ,�, '�� °�. a. r �.� ,,w � » r��.� i .� � , �I I r rr iNs� u I 0. /u +S, ;'' ,���wr+�r;r �rlk u.. 6 ,�" 9" j 1Y � '� �., � 1* i► r 'u;�r TMh� rW," '" `M..w,� k 9} --„� P ITM 01 01 u, M y'I +Wp � M ��:� � ,� �..� � ',' ��n� �;�,,.. w. �' � I� r ,r�,„�pC"� �,/ I►Nr„� MW'. li �,. r�+ I Ny, I MF III I ' y r M f um r� VNu 9 I a I �I I r � y I #1 y fi,,,z„NY�r< II e�„ ply,.• �p �Ma "e1M�Ib 1Na ,:. �6 ,' � ,,e, „ ,� +Nw 'p7N �" � rolA ,,,� ; - / ,, Y)�" • "�N � '�'" ,^�w J" III ,w. * a®, �F "wol �wqy a,� — "' 110 �t ��� 'gW, mm i , w III w If jfrr mm V u w n AM AM .;, lew IJ �;'' olu i , "I ,y14MN`•,.,,.�.,,.rN" iQPLN II A 10 r"•• , "W G r '� QI� i l,� r '� Ism �. i �Ir."" :I" '�' '�'". �'w�»w" "Or' r. � �,. �� �II y m ,e oI�W Ih , I V � I , or I) w h u II`d «r/riwl r,4N.^'M�NMlprra,•,w�,irJ�N9ip� Y�IGdNf'�f/�1�/% PRO,JECT' LOCATION ',. u PROP05ED ADOLDITION5..: AND RENOVAT 10aN15 rp' ".. rs ffIC CE N-TEr"ll' + w� f�C trot o 02139 6 1 I -_l 420 1 ' ' ' —11 ) (Fox) SCALE, 1 4125, '00 NO'RUH ANDOVER, MA55lACHU5ET!T y a_ 3 MW I NO -min ME FIGURE 2 CIS cz -sr � , ezt LYE � 'o 5 __ �. '"_ ......�- E - 7T' (�" �...., . - r s e fir It At a < a °`PAQ a a o ' - _ ff sw f ■ #� n - UMIT5 OF PROP05ED ADDITION � ,r. 3 x I.L.5LA13 EL. +24G.0 v P ARENA COMP" . . � ` - /2 STORY BLOCK an L.L. SLAB L. +246. a a ifwa IF I_ .• r f E r ;� \ __ E _ tr a� �`-� .�....- --- 20 e 3�N CSv.Gam,r.vE - =- � ?-28r• ` s��� �-� ! -� , ,4 TP- _ z 3 Arp tit i He Ir It '�'`' �\ # r t u gr It bvll It ik e, 3#to*o E ADOffmAND S � il LfGEN Y AMN ANORTH - --LOCATION OF TEST PITS PERFORMED 13Y LINCOLN TIES AND LAND5CAPE,INC. REFERENCE:THIS PLAN WA5 PREPARED FROM A 20-5CALE \. ON MA ��,2 FIPAIL RATE ,INC. DRAWING ENTITLED"TOPOGRAPHIC "PLAN F ATE JUNE G,20 BY It ERRIMACK ENGINEERING 5FPVICF5. - -�- LOCATION OF DOREHOLE5 PERFORMED 5 -DFP CORP.ON MARCH 22, 2000 FOR,Mc RhAIL ASSOCIATES,INC, 30 Norfolk Street { fie: 02139 � — 55EPVATIC N WELL INSTALLED IN OMP.ETED BO BOREHOLE. 61 Combri�6�--1 20 „t �tea•. - _�� �� � 1 /6 -1 3(Fox) .IIIII�t �IIIII"1.IIIII'I'.III,III1.III'lll'.IIIIII11. : , ■Illlllli� ��11■IIIIIIII�III 1111 � �BOREHOLE P • 1� _ , �IIIIIIII■Illi��►��lll�lll1■IIIIIIII 3 � : � ; ; 1■ ., ■IIIIIIII■11111111\f��I,III■IIIIIIII � . 4 : 1■ �IIIIIIII■Illlllli��u�� �l■IIIIIIII�IIIIIIII■IIIIIIII■ �IIIIIIII�IIIIIIII��!���i�M���lllllll�llllllll■IIIIIIII■ . , ■IIIIIIII■Illlllll�llli��!1'�1�!!IIIII■IIIIIIII�IIIIIIII� �IIIIIIII■IIIIIIII�IIIII����I�IIIII�IIilllll■IIIIIIII■ GRAVEL SIZE ■IIIIIIII■IIIIIIII�IIIIIII����;IIIII�IIIIIIII■IIIIIIII■ �IIIIIIII■Illlllll�llllllll�llilllll■IIIIIIII■IIIIIIII� PROJECT No. G M.I.T. GRAIN SIZE SCALE Size of opening. inches U.S.S. Sieve size, meshes/inch 100 -- - - TESTMT I LEGEND R - ORE AMPLE ELIEVA110N 2 70 15 . -2 - 23cf) LLJ \�IAL ti 011 1 -- - - - - - w CL All 30 - - 100 10 i .0 1 1 GRAINIZE COBBLE COARSE MEDIUM FINE COARSE MEDIUM FINE SILT SIZE CLAY SIZE SIZE GRAVEL SIZE SAND SIZE FINE GRAINED J Al ASS"Cl "-'PESINC. Geotechnical Engineers APPENDIX A Limitations i flU/Yf �wmYraiW yv r v a, Air py, fly i *"E51INCO, ASSu(...l A l Geotechri*cal Engineers 11 m tat ons This, report has been prepared on behalf of and for the exclusive use of Merrimack, College for specific application to the proposed addition and renovations to the V'01 e Athletic Center Ire North Andovert Massachusetts in, accordance With generally accepted soil and foundation engineering practices. No other warranty,nty, expressed or it plied, is made., r In the event, that any chi n ,es in nature, design or Iocation of the proposed addition and renovations s to the Volpe Athletic Center are planned, the conclusions and re orn en datilo s oor tali d In this report should nr ot, be considered valid unliess the cl an g es are reviewed and conclusions of this report modified or verified Ire Writing. The analyses and recommendations presented in this report are based upon the data obtained frorn test pits performed at the approximate locations, indicated on the enclosed Subsurface Exploration Plan. If variations In the nature and extent of subsurface cond'ition et eer tie widely spaced exploratilons, becomei evident during the course, of construction, it, will be necessary for a re-evaluation of the recommendations of this report to be madle after, performing on-site, observations during the construction pleriod and noting the charalr acteristics, of any variations. cP' ail Associates, Inc. has been retained to provide design assistance to the Architect and Structural Engineer during, the final design phase of this roieet. The purpose, of this involvement is to review the structural foundation drawings and foundation notes for conformance with the recommendations datior erein, and to prepare the earthwork and specialty foundation section of the technical specifications for inclusion into the Contract documents for oonstru do . !� a 1 ASSOCIATE$J Engineer'sGeotechnical APPENDIX Carr-Dee r .'s ng Logs B-1 through B 3 AssociatesPhafl Inc. 'iL g 'T'P-1 through TP-8 McPhail Associates, In ,' Groundwater Monitodng Repots A CARR-DEE CORP. ,37 LINDEN STREET P a 0, BOX 6 7 MEDFORD, MA 02155-0001 Telephone (617) 3.91--450( mr,P,ff,A,1,L, ASIS �3 � I 'A Date: 3-23-0110 0 0C'1,ATE,IS, I NC. 01 1" , I JOb N61 2,0110 o-1 Tb, 0 NORFOLK ST'. CAMBRI,DGE M T,00aitiono- VOLPE CENTERt MERRIMACK COLLEGE N. ANDOVER, MA Scale: 1 in. 4 f t BORENG, i-ow MONITORING WELL GROUND SURFACE 'Elev., +245.0 S#1 01 to 10614 Flush-mount cover LgAA , Trace Graved 41111' Roadway B,ox RECOVERED 10 in. Cancrete 1 4 6", WAI 116,11 to 21 (16) Misc. Cuttings RECOVERED 2 in. FILL, Medium and Coarse Sand and Graviel 416" 1101011 py,c 211 Diameter S#21 SO to 71 Sch. 40 Riser (5-181-36-29) RE COVE R0 11 in., Bems ite Chips We I I Sand S#3 101011 Pvc 211 Diameter to 121 6=0'* (19-22-31-37) Sch. 40 Stouted RECOVERED: 14 in'. Very, Dense, ............... F BL, 'o Some Gra"fie t, CoWes, Inorganic Silt, Trace Boulders (Glacial Till) too S#40 W to 1,6"510 RECOVERED 10 in, %11, %o a S#50 201 to 201911 WeLl Depth 201011 200911 ...................... ('81-100/311) RECOVERED 16 In. WATI'ER LEVEL, 4,116111' SIZE OF AUGERS 3-3/411 I.D., LENGTH 20,0111 DRILLER.- R. DESIMONE, INSPECTOR: R. COLLINS DATE STARTED & CCRIPLE"TED: 3-22-00 All,sa�npjes have beeti visually classified by DRILLER.Utfl ;s Otherwise specified,water levels noted were observed at,completion 0, of borings,and do not necessarilv represent pernmrient Sound water levels. F1 ire$10 parenthesis,indicate the�number of'blows required t,o drive Two-inch Split S3jnpler 6 inclies osing I�40 Ib.wel ht falling inches(±). Figures;gin colurnn to left, noted)indica(e nurnber of blows to drive casing one foot.using �;1b.weight falling 24 inches Sheet I of" 1, i . ry CARR-DEE CORP. 37 LINDEN STREET P.O. BOX 67 MEDFORD, MA 215 -0 0 01 Telephone 17 1 o: MCPHAI L ASS �C AT S INC. , NORFOLK ST. CAM BRIDGE, MA Date:: - - 0 Job No. : 0 Location: VOLPE CENTER, MERRIMACK COLLEGE N. ANDOVER, MA Scale: 1 in. 4 ft BORING 2 GROUND SURFACE Elev. 4242.0 # 511 ASPHALT S# 4# 18 1161, FILL, and, Gravel, Loam, i It - 1' " RECOVERED 6 in. S 1 , 11611 to 21616 Medium Dense, FINE-SAND, 11-14 -.- Some Medium and Coarse Gravel, RECOVERED 7 in. some Inorganic Silt (Glacial Till) 49611 # , 5' to 71 20-25- 7-34 RECOVERED 14 in. Very Dense, FINE -SAND., Some Gravel, Inorganic Sift, Trace Medium and Coarse Sand ( 1 Glacial Till , � � � 26-30-3 -53) RECOVERED 14 ire. 1111 " R E F U S A L - (REFUSAL ENCOUNTERED WITH ROLLERBIT WATER LEVEL 31 SIZE OF AUGERS -3 11 I.D., LENGTH 51011 SIZE OF CASING NW, LENGTH 71011 DRILLER: R. DESI ONE, INSPECTOR: R. COLLINS DATE STARTED & COMPLETED: - 2-00 Alt samples have been visually classified by DRILLER. Unless otherwise specified, water levels noted were observed at complet of borings, and do not necessarily represent permanent ground water levels. Figures in parenthesis indicate the number of bit required to drive Two-inch Split Sampler 6 inches using 140 l b. weight falling 30 inches ± . Figures in column to Left (if noted) indicate number of blows to drive casing one font, using 300 lb. weight falling 24 inches Sheet 1 CARR-DEE CORP. 37 LINDEN' STREET P.O. BOX 67 MI)FORD, 'MA 102155-0001 Telephone (617) 39145 3 0 i "PHAIL ASSOCIATE�,S,,, INC. NORFOLK ST. CAMBRIDGE', MA Date: 323-00, Job Ift MC 2000 VOLPE CENTER,, MERRIMACK COLLEG�S N ANDOVER,, MA Scale 1, in.- 4 f t BORMG 3-OW MONITORING WELL GROIJND SURFACE Elev., 4245*8 S#I, 0 1 to 1,1611 cover FILL (4-27-22-100/0") 411 Roadway Box 1 16 it RECOVERED 10 in. Concrete 11 S#1AP 1161, to 21 (16) /M Sc. Cuttings FILL, Medium and Coarse RECOVERED 2 in. Sand and Gravel 4 4 0613, '101011 Pvc 21, Diameter S#20 51 to 71 S . 40 Riser (5-18-36-219) RECOVERED 11 in. Bentoinite, chipS We,It, Sand S#34 10, to 12, 101011 pvc 211 Diameter (19-22-31-37) Sch. 40 Slotted .,010 RECOVERED 14 'In. *%00 Very Dense,F, M.-t 0 co -SE.SAND$ Some Gravel, Cobbles, inorganic Silt, Trace Boulders (Glacial, Till) S#40 115, to 161511 (28-62-100/5") RECOV5RE'D 10 4, 46, S#51 20, to 2019t, We(( Depth 201011 PO I oil -100/3,11) 1 RECOVERED 6 in. WATER LEVEL 31611 SIZE OF AUGERS 3-3/4" I.D.,, LENGTH 5101; SIZE OF CASING, LENGTH 7100t DRILLER: R. DESIMONE, INSPECTOR.- R. COLLINS DATE STARTED & COMPLETED-. 322-00 A 11 saniples have been v 4�vai ty classified by D R I LLE R. Unlems.ot herwise sped fled,water,far were observed at coniplet)(in I - of borinSs,and do tit iiecessarily reprmnt permanent ground Nvater,levels. ���� spenthesis indicate the numer of blrequired to drive Two-Inch Split Sampler 6 indies using 140 1b. 'I fillinginches(t), Figures in column to left t�'e tt� '� I I(ir noted)indicale nuniber of blows to drive casin j ig 1b.we*S11t,falling 24 inches I _g one foot,u�b 3 Sheet 1 of 4M -MEOW JOB NTEST PIT LOG O. 3G49TEST PIT NO. DATE MARCH 2 ♦ 2000 0 5 10 15 FT. WE => . r GROUND SURFACt EL.+240.5 BROWN 5ANDY SILT.WITh ORGANIC5- TOP501 2.0 ....__ #. r COMPACT DARK BROWN WELL-GRADED 3-u MIXTURE Of 51LT, 5AND AND GRAVEL fILL VERY DENSE LIGHT. BROWN s -GRADED.€ MIXTURE OF r. 5ILT,, AN AND GRAVEL >* 5 • r _ GLACIAL TILL) G!o a ]7J r BOTTOM_ Of TE5T PIT GROUNDWATER 5 I N G I I O TE5T PIT AT A DEPTH OF 2.5 IFEET DURJNG EXCAVATION, r ue Ir r , + E ♦ t = r . . r t . r . . . f . . 4 . r s : s . r. . ;.r . . . . • e r . s r a � t r 1 d #. € . . . . } x 3. e d . .. : r f ., t € . i s. a # •. 4 '. i. .. F T 3 . . x.iF E #'. t t iP $ _ 2 . .. 111L Im. --Wig 11L imL ilL VL IL M 4w AM Aw in- nim- m1w w M7 -dr-- -41r-- JOB N . 3G0 TEST PIT No 2 DATE MARCH 22, 2000 TEST PIT LOG 0 5 10 15 FT. NORTH E::, _a QQItL� i 0 + + GROUND 5UR17AC L,+243,3 # # 0-5 - 13ROWN 5ANDY 51LT COMPACTWELL-GRADED MIXTURE 1TH ORGANIC5 T P501 L Of SILT, SAND AND GRAVEL WITH . NUMEROUS ROOTS,'ORGANIC5 AND BRJCK FILL 3.0 DE-N5E LIGHT BROWN WELL- GRADED MIXTURE 51LTS . SAND AND GRAVEL WITH 5 GCCA51i GLACIAL TILL # + 014AL C01313LE5 * a 4 7.0 . 130TTOM Of TEST PIT + � F 4 • e GROUNDWATER 0135ERVED 5EEPING INTO TEST PIT I� AT A DEPTH Of 3 FEET DURING EXCAVATION. 1 s s s • + s t i s � r ♦ + + s # + + � * • • + + + + s i t # t s + s s e r s s s i s s • s i s * * s • a a } # s • i i • a F * s + 151 . . . y . . . . . •+ . s + .• a . + # s s a r . . .. . + + + + a s . . . + IL ilL 's- IlL IL M -11L IL L m-- L ----- ----- JOB NO. 3------G49 TE%mw PIT L C�G TEST PIT N0. 3 DATE MARCH22. 2404 p 5 14 IS FT. NORTH � � SOUTH p GROUND SURFACE EL.+24 I .9 0.5 151�QVI/N 5AN[7Y SILT WITH ORGANICS ( TOP501L ) 2 Q COMPACT PARK GROWN WELL-GRADED MIXTURE OF 5ILT,, SAND AND GRAVEL WITH NUMEROU5 ROOTS, ORGANIC5 � AN D BRICK ( FILL ) VARY DENSE LIGHT 5RQV4IN WELL- 5 . . . . . . . .� . . . . . . . . . . . . . . . . . . . . . . . . . GRADED MIXTURE t7F'5ILT, SAND C'y AND GRAVEL WiTt-i OCCA510NAL COBB LES AND BOULDER5 � G-0 BOTTOM Of PEST PIT , lz v { GLACIAL TILL ) o W �r � GROUNDWATER 0135ERVED SEEPING INTO TEST PIT � AT A DEPTH 4F 2 FEET DURING EXCAVATION. � WL I- L S S. � ` IL n _mL IL ML VIL MR ju JOB NO. 3649 TE S T P IT LOG TEST PIT NO. 4 DATE MARCH 22. 2000 0 5 10 15 FT. EAST � � WEST p GROUND SURFACE EL.+245.4 BROWN SANDY SILT WITH 0.7 ORGANICS ( TOP501L ) EXISTING CONCRETE 2 p - FILL 3.0 - DENSE BROWN SAND AND GRAVEL, ►� TRACE SILT WITH BRICK AND xy WOOD ( FILL ) [^ 5 . . . . . . . EXISTING CONCRETE WITH PLI1NOOD FORM � v G-5 - � VERY DENSE WELL-GRADED MIXTURE Q x OF 31LT, SAND AND GRAVEL WITIi (� a COBBLES AND BOULDERS ( GLACIAL TILL ) � W � 10 BOTTOM OF TEST PIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C/] ►y z GROUNDWATER OBSERVED 5EEPiNG INTO TEST PIT n AT A DEPTH OF 4.5 FEET DURING EXCAVATION. IS . . . . . . . . . . . . . . . . JOB N 3 49 TEST PIT Lujol"' G TEST PIT NO, 5 DATE AEC 2 2, 200 _ 0 5 10 15 FT. No H <= 4� 1JH GROUND 5URfACC EL.+243.G BROWN 5ANDY 51LT WITH 0.7 - ORG-ANIC5 ( TOP501L ) 5ILTY 5AND WITH OT ( 5UB501L) 2.5 DEN5E LIGHT WELL- GRADED MIXTURE OF 5ILTI 5AND AND GRAVEL \MTH t � OCCA51ONAL .. a F l ! $ ♦ � +p € s a i � € €COBBLE5. $ a z a € ♦ s • t a E n � i f s. } � i r a GLACIAL TILL ) G-0 F 4 t BOTTOM OF TE5T PIT iF GROUNDWATER 055EEP-ING INTO TEST PIT a. F # AT A DEPTH OF 3 fEET DURJNG EXCAVATION. a g i # # a i ME 10 . . . . . . 4 # v g £ t ImLl M.- m JOB No. 3TEST PIT LOG G49 TEST PIT N . DATE MARCH 22, 2000 0 5 10 15 FT. 50UTti 0 r GROUND 5URfAC� EL.+245.7 L f.X15TING CONCR ORGANIC5 ( TOP501L ) 0.5 - IN N 5ANDY 51LT WITH DENSE BROWN 5ANQ AND GRAVEL, } TRACE SILT WITH C013BLE5 ANDi i LLR FILL # + s PLYWOOD FOR . a EX 1 5T I N G CONCRffE �` • t • • t * + , + s• + + • • • • + f.OQIIN!2 s + i i + i + s + + a s + + + • + * + + • + + 5 .2 + + [)EN5E GRAY15H BROWN SiLTY 5AND, 50ME GRAVEL ( GLACIAL TILL 7.0 BOTTOM Of TEST PIT 0 nuj + } + i * + I . . t , t . • t • • + ttt it t + + + + t + • i s + • � • t i• a + + s -# + + + F � r r r * # ♦ # + F i * GROUNDWATER 055ERVED 5EEFING INTO TEST PIT * i AT A DEPTH Of 4 fEET DURING F.XCAVATi . A�e * . + • * s * * * s * # + # i + i # 151 + • . t . t • i + +* t • + + + + + • , i + + + +* a a • # i i + + • * * . . + +t + + ; F 4 • + . . * t t • • • JOB NO. 3G49 TEST PIT No, DATE MARCH 2 2, 2000 TEST PIT LOG 0 5 10 15 FT. 4 1 5QUTH UQ�.Tti 0 . . . r GROUND 5URfAC EL. 2 + .. EX15TING CONC } i + • i # • r DENSE BROWN SAND AND # GRAVEL* TRACE 51LT \MTH COB13LE5 AND 13OULDER5 i # # r -( FILL ) - # 3.5 • # i PLMOOD FORA # # r 51 �. # EX . . .15TI NG i CONCRETE ! • , + + i � • t . ! . r + # # t # ! ! ! t # + r r • # i # a i i i + + . # + a a . a + + • + 5.5 DENSE GRA\rl5H WN GRAVELLY t + ,u. + SAND, 50111E SILT ( GLACIAL TILL ) 7.5 - 130TTOM Of TEST PIT LU + + # • ! •� i ! i a + i i i r • r I t ; # # GROUNDWATER 013SE VED 5EMING INTO TEST PIT T A DEPTH Of 3,5 fEET DURING. EXCAVATION. • i # # t # + # r ! # t + # ! ! } t 1 . , . + • + , i a s , , a a + + # + • r + , i + r i i i ■ 4 # ! ! i i! # # i # i ! t t r F ! # ! Jr; j„ r� i w rf M u i r n y n d w t i w Elevation Job. No. 364,9 Wel'] LD, B-1(0,W) + 8, Subtrahend Job Name: Volpe Center M r'mack College from,Date Time Elapsed Depth of'Water Elevation Remarks Read By R*Box Top of ` 2 715 0 Hourscompletion ' 111/00 84"00 210,Days 4.01 240.8, JJT 0* 7 +239.9 PRW � olwiimilili WOW .� McPHAIL ASSOCIATES, INC. i i orm r p H a f, of ro F l N 4W e n I A Job. No. 3649 Well I.D. B-3(OW) Elievation +2457 Subtrahend Job N - Volpe Center Merrimack College Elapsed Depth of Water Elevation Date Time Time from R*#Box Top of Water Remarks Read By 3/22/00 80*30 0 Hours 4. 241.7 M completion RJC 3 3 0 .4:00 9 Days 2. 242 0,Days & 1 1 4Pi -A low ., 9 5/251/00 �, PRW MOM ............ WIN 111"111,POP 111 0,0WO McPHAIL ASSOCIATES, INC. i d I Stormwater Report Appendix D*. Standard 4 Computations and Supporting Information > Operations and Maintenance Plan > Water Quality Volume Calculations > TSS Removal Worksheets D-1 Appendix D:Standard 4 Computations and Supporting Information t trim t it I[:Ze1 ,irt uuuu i i i I uumlm I I,j d aI,,, uuu uuum I uum� I�Iluu uuuumuuul uuu uu II D-2 Appendix D:Standard 4 Computations and Supporting Information ,,,11C,,,,C,;; I1!!! III IIC IIE;;;;;;III!! II „II �;;��IIE;;;;;;II IIE;;;;;;III lIC � �IIC IIE;;;;;;II „ IIC IIE;;;;;;III IIC III AND MAIN lIC IIE;;;;;;IIII III IIE;;;;;; MANUAIL...... Merrimack MAC Stora 9 e 0 0 Building �;rcmnupI�I�N I� ouuuuuum uuuuuum iyDyis �IIU wmax�nn� �IAIW�� u u'G�r""I ''tl��,,,�p,,e uuuyIIUYIIryIIIkIII�IIIIklvuuuxi Ni�H NiNug1 Nuomg4 uuuV��IIIIIfklyuuuxi .''... x 'Wduo, IIIIIIipu m�N�� INoi�W h4NNnnnu!�o �IPNnnnu!�o 'Nh10 NI pIWUUdp� q�UlAl uuu DIDk „4!A'�'H A��r"idov&�r, OI@Ipp��,, �iDU ��'VI�A uuuimayillptlllryl r /! �f O VIST, 19471 Merrimack College 315 Turnpike Street North Andover, MA, 01845 978.837.5000 IIC IIC� IIC,;;;;C,IIC IIC IIC,;;;;C,IIC;�; IIC Y ow 101 Walnut Street PO Box 9151 Watertown, MA 02471 617.924.1770 Operations and Maintenanceare I Merrimack MAC Storage Building,North Andover, MA Table of Contents ProjectInformation...............................................................................................................iii SectionA: Source Control ......................................................................................................1 Section B: Spill Prevention.....................................................................................................1 B.1 Initial Notification........................................................................................................................1 B.2 Further Notification.....................................................................................................................1 B.3 Assessment— Initial Containment.........................................................................................4 SectionC: Snow Management...............................................................................................1 Section D: Maintenance of Stormwater Management Systems.........................................1 D.1 Pavement Systems.......................................................................................................................1 D.1.1 Standard Asphalt Pavement....................................................................................1 D.2 Structural Stormwater Management Devices...................................................................1 D.2.1 Stormwater Outfalls....................................................................................................1 D.3 Vegetated Stormwater Management Devices.................................................................2 D.3.1 Surface Infiltration/Detention Basins...................................................................2 D.3.2 Vegetated Areas Maintenance...............................................................................2 Section E: Operations and Maintenance Plan Summary.....................................................1 E.1 Routine Maintenance Checklists............................................................................................1 E.2 Reporting and Documentation..............................................................................................1 E.3 Construction Practices Maintenance/ Evaluation Checklist........................................2 EA Long-term Maintenance/Evaluation Checklist.................................................................3 E.5 Maintenance Checklists and Device Location Maps......................................................4 Section F: Erosion and Sedimentation Control Measures ...................................................1 i Table of Contents Operations i n I Merrimack MAC StorageBuilding, North Andover, Prqj'Dect Informat,ion Site Merrimack MAC Storage Building 315 Turnpike Street North Andover, MA Contractor Joe Gaukstern Channel Building 355 Middlesex Avenue Wilmington, MA 01887 978.657.7788 Facility Manager Felipe R. Schwarz Merrimack College 315 Turnpike Street North Andover, MA 01845 978.837.5459 Site Contact Name: Telephone: Cell phone: Email: iii Project Information Operations and Maintenance Plan I Merrimack MAC Storage Building,North Andover, MA Section A0. Source Control Operations and i IMerrimack MAC Storage Building, Andover, MA 10 Imov I A Source Control A comprehensive source control program will be implemented at the Merrimack MAC Storage Building Site, which includes the following components: > Regular pavement sweeping > Catch basin cleaning > Clearing litter from the parking area, islands, and perimeter landscape areas > Enclosure and regular maintenance of all dumpsters > Spill Prevention training A-1 Source Control Operations and Maintenance Plan I Merrimack MAC Storage Building, North Andover,MA Section B: Spill Prevention Operations and i IMerrimack MAC Storage Building, Andover, MA 10 1=0V I B Spill Prevention Spill prevention equipment and training will be provided by the College. �n iltIIIII a�� �N ' IIIII' IIIII c at ii o�n In the event of a spill the facility and/or construction manager or supervisor will be notified immediately. Facility Manager (name): Felipe R. Schwarz— Merrimack College Facility Manager (phone): 978-837-5459 Construction Manager (name) : Joe Gaukstern—Channel Building Construction Manager (phone): 978-657-7788 The supervisor will first contact the Fire Department and then notify the Police Department, the Public Health Commission and the Conservation Commission. The Fire Department is ultimately responsible for matters of public health and safety and should be notified immediately. �B .2 ""'�u ' I IIIII' IIIII c at iii o�n Based on the assessment from the Fire Chief, additional notification to a cleanup contractor may be made. The Massachusetts Department of Environmental Protection (DEP) and the EPA may be notified depending upon the nature and severity of the spill.The Fire Chief will be responsible for determining the level of cleanup and notification required.The attached list of emergency phone numbers shall be posted in the main construction/facility office and readily accessible to all employees.A hazardous waste spill report shall be completed as necessary using the attached form. B-1 Spill Prevention Operations and MaintenanceIMerrimack MAC StorageBuilding, v Emergency Notification Phone Numbers 1. FACILITY MANAGER Name: Felipe R. Schwarz Phone: 978-837-5459 Beeper/Cell: 978-857-1845 Home Phone: Alternate Contact: John Waters Phone: 978-895-3252 Beeper/Cell: Home Phone: 2. FIRE & POLICE DEPARTMENT Emergency: 911 3. CLEANUP CONTRACTOR Address: Phone: 4. MA DEPARTMENT OF ENVIRONMENTAL PROTECTION (DEP) Emergency: (978) 694-3200 5. NATIONAL RESPONSE CENTER Phone: (800) 424-8802 Alternate: U.S. Environmental Protection Agency Emergency: Business: 6. NORTH ANDOVER HEALTH DEPARTMENT Phone: (978) 688-9540 North Andover Conservation Commission: Phone: (978) 688-9530 B-2 Spill Prevention Operations and i are I Merrimack MAC Storage Building, Andover, MA Hazardous Waste & Oil Spill Report Date: Time: AM/PM Exact location (Transformer#): Type of equipment: Make: Size: S/N: Weather Conditions: On or near water? ❑ Yes If es, name of body of water: ❑ No y y Type of chemical/oil spilled: Amount of chemical/oil spilled: Cause of spill: Measures taken to contain or clean up spill:ill: Amount of chemical/oil recovered: Method: Material collected as a result of cleanup: drums containing drums containing drums containing Location and method of debris disposal: Name and address of any person, firm, or corporation suffering charges: Procedures, method,and precautions instituted to prevent a similar occurrence from recurring: Spill reported by General Office by: Time: AM/ PM Spill reported to DEP/National Response Center b P P P Y DEP Date: Time: AM / PM Inspector: N RC Date: Ti me: AM / PM Inspector: Additional comments: B-3 Spill Prevention Operations i c I Merrimack MAC Storage Building, Andover, MA �B.3 °°° .°°°°°°°°°. IIIII' IIIII Can'taiinmen't The supervisor or manager will assess the incident and initiate containment control measures with the appropriate spill containment equipment included in the spill kit kept on-site.A list of recommended spill equipment to be kept on site is included on the following page. Fire/ Police Department: 911 North Andover Health Department: (978) 688-9540 North Andover Conservation (978) 688-9530 Commission: Emergency Response Equipment The following equipment and materials shall be maintained at all times and stored in a secure area for long-term emergency response need. Supplies Quantity Recommended Suppliers Sorbent Pillows/"Pigs" 2 ,Ihttp�// .ne is%corm Item#KIT276 —mobile container with two pigs Sorbent Boom/Sock 25 feet M.W..Q//.........................................e. it :.Ir .:::::..s. ...p..p.11..ii_ it .co Sorbent Pads 50 Lite-Dri® Absorbent 5 pounds Shovel 1 Item#33934—Shovel (or equivalent) Pry Bar 1 Item#43210—Manhole cover pick(or equivalent) Goggles 1 pair Item#23334—Goggles(or equivalent) Gloves— Heavy 1 pair Item#90926—Gloves(or equivalent) B-4 Spill Prevention Operations and Maintenance Plan I Merrimack MAC Storage Building, North Andover,MA Section C: Snow Management Operations and Maintenanceare IMerrimack MAC Storageui i ,North Andover, MA 10 Imov I C Snow Management Snow storage areas are shown on the attached Map. Snow storage areas will be managed to prevent blockage of storm drain catch basins and stormwater drainage swales. Snow combined with sand and debris may block a storm drainage system, diminishing the infiltration capacity of the system and causing localized flooding. > Sand and debris deposited on vegetated or paved areas shall be cleared from the site and properly disposed of at the end of the snow season, no later than May 15. > Snow shall not be dumped into any waterbody, pond, or wetland resource area/25-ft no disturb zone. C-1 Snow Management Operations and Maintenance Plan I Merrimack MAC Storage Building, North Andover, MA Section D: Maintenance of Stormwater Management Systems Operations and MaintenanceIMerrimack MAC Storage Building, , MA 10 1=0V I D Maintenance of Stormwater Management S oft ystems ��,',)avement Systems ��D.11.11 Standard Asphalt Pavernen't Sweep or vacuum standard asphalt pavement areas at least four times per year with a rotary brush sweeper and properly dispose of removed material. Recommended sweeping schedule: o Oct/Nov o Feb/Mar o Apr/May o Aug/Sep More frequent sweeping of paved surfaces will result in less accumulation in catch basins, less cleaning of subsurface structures, and less disposal costs. Check loading docks and dumpster areas frequently for spillage and/or pavement staining and clean as necessary. D.2 Structu4�� Stormwater Management ��',',)eviices ��D.2.11 StarmwalterI The stormwater drainage system at the Project has two (2) outfall locations into the infiltration and a third location where treated stormwater is discharged to surface wetlands via a stone channel overflow from the proposed infiltration basin.A map of these locations is included in Section E.5 Maintenance Checklists and Device Location Maps. > Inspect outfall locations monthly for the first three months after construction to ensure proper functioning and correct any areas that have settled or experienced washouts. > Inspect outfalls annually after initial three-month period. Annual inspections should be supplemented after large storms, when washouts may occu r. D-1 Maintenance of Stormwater Management Systems Operations and MaintenanceI Merrimack MAC Storage Building, Andover, MA Maintain vegetation around outfalls to prevent blockages at the outfall. > Maintain rip rap pad below each outfall and replace any washouts. > Remove and dispose of any trash or debris at the outfall. Vegetated Stormwater Surface �II III�" III' " II � s� III 't ��III" III II III III' s There is one (1) surface infiltration/detention ponds included in the Project. The infiltration/detention ponds are partially vegetated basins that are designed to detain, clean and infiltrate roadway and rooftop runoff. The maintenance of the infiltration basins may affect the functioning of stormwater management practices. This includes the condition of the side slope vegetation and the sediment deposits in the bottom of the ponds. Initial Post-construction Inspection > Infiltration basins should be inspected after every major storm for the first few months to ensure proper stabilization and function. Long-term Maintenance > The grass on the sideslopes and in the buffer areas should be mowed, and grass clippings, organic matter, and accumulated trash and debris removed, at least twice during the growing season. > Eroded or barren spots should be reseeded immediately after inspection to prevent additional erosion and accumulation of sediment. > Deep tilling can be used to break up a clogged surface area. > Sediment should be removed from the basin as necessary. Removal procedures should not take place until the floor of the basin is thoroughly dry. Inspections and Cleaning > Infiltration basins should be inspected at least twice a year to ensure proper stabilization and function. > Light equipment, which will not compact the underlying soil, should be used to remove the top layer. D3.2 VegetatedI e w Ill II It.II II Although not a structural component of the drainage system,the maintenance of vegetated areas may affect the functioning of the stormwater management system.This includes the health/density of vegetative cover and activities such as the application and disposal of lawn and garden care products, disposal of leaves and yard trimmings and proper aeration of soils. > Inspect planted areas on a semi-annual basis and remove any litter. D-2 Maintenance of Stormwater Management Systems Operations and i I Merrimack MAC StorageBuilding,North Andover, MA > Maintain planted areas adjacent to pavement to prevent soil washout. > Immediately clean any soil deposited on pavement. > Re-seed bare areas; install appropriate erosion control measures when native soil is exposed or erosion channels are forming. > Plant alternative mixture of grass species in the event of unsuccessful establishment. > The grass vegetation should be cut to a height between three and four inches. > Pesticide/Herbicide Usage— No pesticides are to be used unless a single spot treatment is required for a specific control application. > Fertilizer usage should be avoided. If deemed necessary, slow release fertilizer should be used. Fertilizer may be used to begin the establishment of vegetation in bare or damaged areas, but should not be applied on a regular basis unless necessary. Annual application of compost amendments and aeration are recommended. D-3 Maintenance of Stormwater Management Systems Operations i I Merrimack MAC Storage Building, , MA Operations and i IMerrimack MAC StorageBuilding,North Andover, MA 10 1=0V I E Operations and Maintenance Plan Summary This Operation and Maintenance Plan has been prepared in accordance with the Stormwater Management Policy developed by the DEP, as well as the Town of North Andover Stormwater Management and Erosion Control Regulations as applicable. It specifies operational practices and drainage system maintenance requirements for the MAC Storage Building. Requirements should be adjusted by the site manager as necessary to ensure successful functioning of system components. ��Routilne Mailatenance Check��ilsts Routine required maintenance is described in Sections A— D. The following checklists are to be used by the property manager to implement and document the required maintenance and inspection tasks. �E.2 ���Zepartiing and The site supervisor shall be responsible for ensuring that the scheduled tasks as described in this plan are appropriately completed and recorded in the Maintenance Log. Accurate records of all inspections, routine maintenance and repairs shall be documented and these records shall be available for inspection by members of the North Andover Conservation Commission or other designated body, or their designated agent, upon request. The Maintenance Log shall: > Document the completion of required maintenance tasks. > Identify the person responsible for the completion of tasks. > Identify any outstanding problems, malfunctions or inconsistencies identified during the course of routine maintenance. > Document specific repairs or replacements. E-1 Operations and Maintenance Plan Summary Operations and MaintenanceI Merrimack MAC Storage Building, Andover, MA Canstructilan ""'� ����������� IIIII I Chedk���ilst Merrimack MAC Storage Building — North Andover, MA Cleaning or Best Repair Needed Date of Management Inspection Date Inspector Minimum Maintenance ❑Yes/No Cleaning Performed Practice Frequency Inspected Initials and Key Items to Check (List Items) or Repair by: Siltsock/ Weekly and Sediment build up,broken Silt Fencing after any bales or stakes rainfall Gravel Weekly and Filled voids,runoff/sediments Construction after any into street Entrance rainfall Catch Basin Weekly and Clogged or sediment build- Protection after any up at surface or in basin rainfall Diversion Weekly and Maintained,moved as Channels after any necessary to correct locations, rainfall Check for erosion or breakout Temporary Weekly and Cracking,erosion,breakout, Sedimentation after any sediment buildup, Basins rainfall contaminants Stormwater Control Manager: E-2 Operations and Maintenance Plan Summary Operations and MaintenanceI Merrimack MAC Storage ui i , North Andover, MA ang°°°° IIIII IIIIIChe ilst Merrimack MAC Storage Building — North Andover, MA Minimum Cleaning or Date of Best Maintenance Repair Cleaning Management and Key Items Inspection Date Inspector Cleaning Needed or Performed Practice to Check Frequency Inspected Initials Frequency ❑Yes/No Repair by: Street Vacuum sweeper 4X per year 4X per year* Sweeping minimum Outfall Remove debris and 1X per year 1X per year Structures excess vegetation, replace any dislodged riprap Infiltration Inspect inlets, 2X per year 2X per year Basins vegetation,overflow first year, first year, discharge pipes, annually annually drain time less than thereafter thereafter 4 days * Recommend sweeping Oct/Nov,Feb/Mar,Apr/May Jul/Aug with late winter most important Stormwater Control Manager: E-3 Operations and Maintenance Plan Summary Operations and i I Merrimack MAC StorageAndover, Maild ilsts *ce ncafian Maps IIIII These checklists are provided for the maintenance crew to photocopy and use when conducting inspections and cleaning activities to the stormwater management systems. E-4 Operations and Maintenance Plan Summary Operations and Maintenanceare I Merrimack MAC Storageui i ,North Andover, MA Maintenance Checklists F-1 Operations and Maintenance Plan Summary Operationsairy I Merrimack MAC Storage Building, Andover, Outfalls—Inspect 4 times per year, replace any dislodged rip-rap, remove excess vegetation, remove any Sediment Cleaning I nspected Depth needed Date Outfall (Y/N) (inches) (Y/N) Cleaned Comments(Trash, Oil, Pet waste, Lawn Debris, Damage) Overflow FES-102 FES-103 Infiltration/Detention Basins— Inspect once per year, remove sediment if more than 6 linches has accumulated 'in sediment forebay or sediment collection row. Sediment Cleaning I nspected Depth needed Date Basin (Y/N) (inches) (Y/N) Cleaned Comments(Trash, Oil, Pet waste, Lawn Debris, Damage) IB#1 F-2 Operations and Maintenance Plan Summary Operations and Maintenanceare I Merrimack MAC Storageui i ,North Andover, MA Device Location Maps F-3 Operations and Maintenance Plan Summary \\vhb.com\gbl\proj\Wat-LD\11625.25 Butler Building\cad\ld\Eng\Stormwater\11625.25-Stormwater BMP Location Plan.dwg � 1oo'sz 100. fir. •\ \ ,---- ------ --- - - UD- -- - PR SED \ STORAGE BLD �\ t �o ,L 1 � � aawoz EN HD 0 D EN g , a - ►W. 245 ,iW GG .. .x. ,:. 25 4 1, 7 .., ............................ -------- l iz5v Z .. ..... LEGEND Q JB y INFILTRATION BASIN .. TRENCH DRAIN SS EXISTING MERRIMACK ATHLETICS CENTER t O UNDERDRAIN UD Z8,001 e_ �.-w � ze.00�- Z9AOt �4 ______ POTENTIAL SNOW STORAGE } \ LOCATION I � NOTE: SNOW SHALL NOT BE STORED IN WETLAND RESOURCE AREAS OR INFILTRATION BASIN. ALL EXCESS SNOW SHALL BE TRUCKED TO DESIGNATED STORAGE AREA. Vhb Stormwater BMP Location Plan Figure D1 b Merrimack MAC Storage Building 315 Turnpike Street July 7,2022 0 20 40 Feet North Andover,Massachusetts Operations and Maintenanceare I Merrimack MAC Storageui i ,North Andover, MA Snow Storage Areas Map F-5 Operations and Maintenance Plan Summary \\vhb.corn\gbl\proj\Wat-LD\11625.25 Butler Building\cad\Id\Eng\Stormwater\11625.25-SNOW.dwg / 1F1-97 WF1-96 ' W 50 F1-95 No2 Legend n_ 25,jv0Z .000� �� o0 WF1-101 WF1-94 N SNOW STORAGE vm-102 25 N Dz --- �`S�i 25 NDZ wFA-103 wFA-104 WF1-110 END 06 - ` 1WF-103 FA- 1D7W WA105 WF1-104 WFA AL WF21C?� WF1 105 10 101 ..W V - 10 2 1051 W 102 WF2 W-1-107 WF2-103 �F2104 6 F1- A- W F 1 10 8 Z N S - ". Z ........... ZN Z 0 ,, Z© .........:: GNP Z'QN-ag _. ........... o ........... z . za e �\ Lk ....................... ................\ ............ ................. -\...........E'�.....................-'- ......... �, ..... 4 PROPOSED SNOW ""4 Z8.n STORAGE LOCATION �,�� AHI Z8,00 L - e� ,,. a \ \\\\ _ q r _ s N'oVhb Snow Storage Figure D-1 A Merrimack MAC Storage Building 31 S Turnpike Street 7/7/2022 0 20 40 Feet North Andover,MA Operations and Maintenance I Merrimack MAC Storage Building, Andover,MA Section F: Erosion and Sedimentation Control Measures F-1 Operations and Maintenance Plan Summary Operations i IMerrimack MAC Storage Building,North Andover, MA 10 1=0V I F Erosion and Sedimentation Control Measures The following erosion and sedimentation controls are for use during the earthwork and construction phases of the project.The following controls are provided as recommendations for the site contractor and do not constitute or replace the final Stormwater Pollution Prevention Plan that must be fully implemented by the Contractor and owner in Compliance with EPA NPDES regulations. ���:.J Hay bale barriers will be placed to trap sediment transported by runoff before it reaches the drainage system or leaves the construction site. Bales will be set at least four inches into the existing ground to minimize undercutting by runoff. �F.2 S'il ii�n g In areas where high runoff velocities or high sediment loads are expected, hay bale barriers will be backed up with silt fencing. This semi-permeable barrier made of a synthetic porous fabric will provide additional protection. The silt fences and hay bale barrier will be replaced as determined by periodic field inspections. �F.3 Catch Basil 3 IIIII Newly constructed and existing catch basins will be protected with hay bale barriers (where appropriate) or silt sacks throughout construction. FA G ilon A temporary crushed-stone construction entrance/exit will be constructed. A cross slope will be placed in the entrance to direct runoff to a protected catch basin inlet or settling area. If deemed necessary after construction begins, a wash pad may be included to wash off vehicle wheels before leaving the project site. F-1 Erosion and Sedimentation Control Measures Operations and Maintenance Plan I Merrimack MAC Storage Building,North Andover, MA �F.5 *an Chann6�s IIIII Is IIIII Diversion channels will be used to collect runoff from construction areas and discharge to either sedimentation basins or protected catch basin inlets. �F.6 remparary SedilI s IIIII Temporary sediment basins will be designed either as excavations or bermed stormwater detention structures (depending on grading)that will retain runoff for a sufficient period of time to allow suspended soil particles to settle out prior to discharge. These temporary basins will be located based on construction needs as determined by the contractor and outlet devices will be designed to control velocity and sediment. Points of discharge from sediment basins will be stabilized to minimize erosion. 7 Vegetatil IIIII IIIII""""' IIIII Stabilization of open soil surfaces will be implemented within 14 days after grading or construction activities have temporarily or permanently ceased, unless there is sufficient snow cover to prohibit implementation. Vegetative slope stabilization will be used to minimize erosion on slopes of 3:1 or flatter. Annual grasses, such as annual rye,will be used to ensure rapid germination and production of root mass. Permanent stabilization will be completed with the planting of perennial grasses or legumes. Establishment of temporary and permanent vegetative cover may be established by hydro-seeding or sodding. A suitable topsoil,good seedbed preparation, and adequate lime, fertilizer and water will be provided for effective establishment of these vegetative stabilization methods. Mulch will also be used after permanent seeding to protect soil from the impact of falling rain and to increase the capacity of the soil to absorb water. �F.8 �M a ilI ' °°°°�n a�n c e The contractor or subcontractor will be responsible for implementing each control shown on the Sedimentation and Erosion Control Plan. In accordance with EPA regulations, the contractor must sign a copy of a certification to verify that a plan has been prepared and that permit regulations are understood. The on-site contractor will inspect all sediment and erosion control structures periodically and after each rainfall event. Records of the inspections will be prepared and maintained on-site by the contractor. Silt shall be removed from behind barriers if greater than 6-inches deep or as needed. Damaged or deteriorated items will be repaired immediately after identification. The underside of hay bales should be kept in close contact with the earth and reset as necessary. F-2 Erosion and Sedimentation Control Measures Operations and Maintenancen I Merrimack MAC Storage Building,North Andover, MA Sediment that is collected in structures shall be disposed of properly and covered if stored on-site. Erosion control structures shall remain in place until all disturbed earth has been securely stabilized.After removal of structures disturbed areas shall be regraded and stabilized as necessary. The sedimentation and erosion control measures are included in project plan set. F-3 Erosion and Sedimentation Control Measures t trim t it I[:Ze1 ,irt Wallllllte��r- Qua uuu uuum � io uuuummm uu D-3 Appendix D:Standard 4 Computations and Supporting Information f,1 r r title (Jfll' 0 11b Water Quality Volume Calculations Project Merrimack MAC Storage Project# 11625.25 Building Calculated by N DS Date 6/29/2022 Checked by J K Date 6/29/2022 BASIN P-1 Runoff from subcatchment areas 11, 13 Water Quality Storm Runoff Depth (in) 0.5 Total Impervious Area (ft2) 8,670 BASIN WQV: Required Volume: Runoff Depth to be Treated Required Volume (in) (ft) 0.5 361 Provided Volume: Area Cumulative Volume Elevation z 3 (ft ) (ft ) 242.9 645 0 243.4 865 378 FREEBOARD CHECK: 100-YR Peak Elevation: 243.88 Maximum Basin Elevation: 243.9 Basin Freeboard: 0.0 *Per MassDEP Treatment Requirement \\vhb\gbl\prof\Wat-LD\11625.25 Butler Bu1ld1ng\ssheets\11625.25-Water Quality Volume Calculations 1 of 1 t trim t it I[:Ze1 ,irt mu ���lllllln ova Im,ii m� uuu umim ii uuuuuuuuul D-4 Appendix D:Standard 4 Computations and Supporting Information e VIP vilb Project Name: MAC Storage Building Sheet: 1 of 1 VHB, Inc.. Project Number: 11625.25 Date: 06/28/22 101 Walnut Street Location: North Andover, MA Computed by: NDS Post Office Box 9151 JWK Watertown, MA 02471 Discharge Point: DP-1 Checked by: P 617.924.1770 Drainage Area(s): 11, 13 A B C D E ..... BMA* TSS c� Remval Rate* Starting TSS Lt�ad** Amount Remc�ued Remaining.Lead Q ('C'*,D) Q Infiltration Basin 80% 1.00 0.80 0.20 0% 0.20 0.00 0.20 0% 0.20 0.00 0.20 0% 0.20 0.00 0.20 0% 0.20 0.00 0.20 * BMP and TSS Removal Rate Values from the MassDEP Stormwater Handbook Vol. 1. Treatment Train ** Equals remaining load from previous BMP (E) 80% TSS Removal = \\vhb.com\gbl\prof\Wat-LD\11625.25 Butler Building\ssheets\11625.25-TSS Removal Calculations brim heir I[:Zeport Appendix E: Standard 6 Supporting Information Critical Areas Map E-1 Appendix E: Standard 6 Supporting Information t iirin t rr III II iirt C c a a s ��M a E-2 Appendix E: Standard 6 Supporting Information LegendSl*te Areas of Critical Environmental Concern (ACECo) Surface Water Protection Area — Zone A |WpAo Zone Us Outstanding Resource Waters: Public Water Supply Contributor DRVV For ACEC DRVV For Both Water Supply and Other V# h�b� Critical Areas for StorrnwaterDischarges Figure El Merrimack MAC Storage Building 315 Turnpike Street July 7' 2022 0 250 500Feet North Andover, MA to riirm t&rr IlRepo in Appendix F: Standard 10 Supporting Information Illicit Discharge Statement E-1 Appendix F: Standard 10 Supporting Information t iiriirn teiir lReport IIIIIIIIIIII mm mmmmu o c P I uuumuml uuu uuum I uuu uuum uuuumuum I pumm uuu It E-2 Appendix F: Standard 10 Supporting Information Illicit Discharge Statement The design plans submitted with this report have been designed so that the components included therein are in compliance with the current MassDEP and municipal standards as noted. The Project includes surface improvements to the stormwater management system of the redeveloped impervious areas. No impacts will be made to sanitary sewer systems beyond potential relocation of an existing sanitary force main. Measures to prevent illicit discharges are included in the Construction Period and Long-Term Pollution Prevention Plans included in the Stormwater Report. The Owner, Merrimack College, understands that no illicit discharges are allowed into the stormwater system. 11vhb.com\gbl\proj\Wat-LD\11625.25 Butler Building\Reports\Stormwater\Appendix F- Standard 10 Computations and Supporting Information\F1-Illicit Discharge Statement.doc