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2024/10/30 - Stormwater Management Report - -
STORMWATER MANAGEMENT REPORT Lecture Hall at Merrimack College 5 ee t IlpNadaN� INA (""j , CIII oljjj[["�)vfe I M A, PREPARED FOR Merrimack College 315 Turnpike Street North Andover, MA 01845 978.837.5000 PREPARED BY 260 Arsenal Street#2 PO Box 9151 Watertown, MA 02472 617.924.1770 SqF-)teiir--r fl[�)eiir„ 12111"', 2024. [[ eviSE?d Octo[aer 30111", 2024'.] brim heir I[:,e it t Table of Contents Checklistfor Stormwater Report...................................................................................................3 Stormwater Report Narrative.........................................................................................................4 ProjectDescription............................................................................................................................................................4 SiteDescription...................................................................................................................................................................4 Merrimack College Stormwater Management Plan.............................................................................................5 ExistingDrainage Conditions........................................................................................................................................5 ProposedDrainage Conditions....................................................................................................................................6 RegulatoryCompliance.................................................................................................................15 Massachusetts Department of Environmental Protection (DEP)—Stormwater Management Standards and North Andover Stormwater Regulations.................................................................................15 Standard 1: No New Untreated Discharges or Erosion to Wetlands.............................................15 Standard2: Peak Rate Attenuation.............................................................................................................15 Standard3: Stormwater Recharge...............................................................................................................16 Standard4:Water Quality...............................................................................................................................17 Standard 5: Land Uses with Higher Potential Pollutant Loads (LUHPPLs)...................................17 Standard6: Critical Areas................................................................................................................................17 Standard 7: Redevelopments and Other Projects Subject to the Standards only to the MaximumExtent Practicable.................................................................................................17 Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Controls.........................................................................................................................................17 Standard 9: Operation and Maintenance Plan........................................................................................17 Standard 10: Prohibition of Illicit Discharges..........................................................................................18 Appendices Appendix A: Standard 1 Computations and Supporting Information................................................A-1 Appendix B: Standard 2 Computations and Supporting Information................................................B-1 Appendix C: Standard 3 Computations and Supporting Documentation........................................C-1 Appendix D: Standard 4 Computations and Supporting Information................................................D-1 Appendix E: Standard 8 Supporting Information........................................................................................E-1 Appendix F: Standard 10 Computations and Supporting Information..............................................F-1 Appendix G: Approved Stormwater Management Plan Documents..................................................G-1 i Table of Contents S,tormwate [:�eport List � Tables�N� Table No. Description Page Table 1 Existing Conditions Hydrologic Data..........................................................................................S Table 2 Proposed Conditions Hydrologic Data......................................................................................6 Table 3 Peak Discharge Rates (cfs)............................................................................................................16 Table 4 Stormwater Volume Analysis (ac-ft)---_---_--------._--------._.16 Table S Summary of Recharge Ca|cu|adons— —_. -----16 n Table ofContents t iirir e r I[:,eat t Checkl*lst for Stormwater Report 3 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, w 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. MassDEP Stormwater Checklist-04/01/08 Stormwater Report Checklist-Page 1 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program � Checklist for Stormwater Report 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 .f\\A of MASs��y � DIANE F, o TRAN No. 54369 ��FFSS/O N A L 9/11/2024 Signature and Date Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment? M New development ❑ Redevelopment ❑ Mix of New Development and Redevelopment MassDEP Stormwater Checklist•04/01/08 Stormwater Report Checklist•Page 2 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program � Checklist for Stormwater Report 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: M No disturbance to any Wetland Resource Areas ❑ Site Design Practices (e.g. clustered development, reduced frontage setbacks) ❑ Reduced Impervious Area (Redevelopment Only) ❑ Minimizing disturbance to existing trees and shrubs ❑ LID Site Design Credit Requested: ❑ Credit 1 ❑ Credit 2 ❑ Credit 3 ❑ Use of"country drainage"versus curb and gutter conveyance and pipe ❑ Bioretention Cells (includes Rain Gardens) ❑ Constructed Stormwater Wetlands (includes Gravel Wetlands designs) ❑ Treebox Filter ❑ Water Quality Swale ❑ Grass Channel ❑ Green Roof Z Other(describe): On-site infiltration Standard 1: No New Untreated Discharges Z No new untreated discharges Z Outlets have been designed so there is no erosion or scour to wetlands and waters of the Commonwealth Z Supporting calculations specified in Volume 3 of the Massachusetts Stormwater Handbook included. MassDEP Stormwater Checklist•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. E Static El 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. MassDEP Stormwater Checklist-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; 0 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. MassDEP Stormwater Checklist-04/01/08 Stormwater Report Checklist-Page 5 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checki'Ist Stormwater Report Checklist (continued) Standard 4: Water Quality (continued) ® The BMP is sized (and calculations provided) based on: ® The 1/2" or 1"Water Quality Volume or ❑ The equivalent flow rate associated with the Water Quality Volume and documentation is provided showing that the BMP treats the required water quality volume. ® The applicant proposes to use proprietary BMPs, and documentation supporting use of proprietary BMP and proposed TSS removal rate is provided. This documentation may be in the form of the propriety BMP checklist found in Volume 2, Chapter 4 of the Massachusetts Stormwater Handbook and submitting copies of the TARP Report, STEP Report, and/or other third party studies verifying performance of the proprietary BMPs. ❑ A TMDL exists that indicates a need to reduce pollutants other than TSS and documentation showing that the BMPs selected are consistent with the TMDL is provided. Standard 5: Land Uses With Higher Potential Pollutant Loads (LUHPPLs) Not a LUPPHL ❑ 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 Does not discharge to or near a critical area ❑ 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. MassDEP Stormwater Checklist-04/01/08 Stormwater Report Checklist-Page 6 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checkl'ist Stormwater Report Checklist (continued) Not a redevelopment Standard 7: Redevelopments and Other Projects Subject to the Standards only to the maximum extent practicable ❑ The project is subject to the Stormwater Management Standards only to the maximum Extent Practicable as a: ❑ Limited Project ❑ Small Residential Projects: 5-9 single family houses or 5-9 units in a multi-family development provided there is no discharge that may potentially affect a critical area. ❑ Small Residential Projects: 2-4 single family houses or 2-4 units in a multi-family development with a discharge to a critical area ❑ Marina and/or boatyard provided the hull painting, service and maintenance areas are protected from exposure to rain, snow, snow melt and runoff ❑ Bike Path and/or Foot Path ❑ Redevelopment Project ❑ Redevelopment portion of mix of new and redevelopment. ❑ Certain standards are not fully met (Standard No. 1, 87 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. MassDEP Stormwater Checklist-04/01/08 Stormwater Report Checklist-Page 7 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program � Checklist for Stormwater Report Checklist (continued) Standard 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. MassDEP Stormwater Checklist•04/01/08 Stormwater Report Checklist•Page 8 of 8 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).This report also demonstrates compliance with the Town of North Andover and Town of Andover rules and regulations for stormwater management and erosion control design and mitigation. It 0 uuuu 1111111jec''It The Applicant, Merrimack College (owner), is proposing to construct a Lecture Hall (the Project). As proposed, the Project consists of 19,205 square feet of building space, ancillary landscape improvements, utility infrastructure and a stormwater management plan to support this use. The Project is not considered a Land Use with Higher Potential Pollutant Loads (LUHPPL). p0 um uuuuuum i i The Project Site is located on Merrimack College Campus (the Site) at 315 Turnpike Street in North Andover, Massachusetts (see Figure 1).The Site is bounded by Turnpike Street/Route 114 to the northeast, Elm Street to the northwest, and Flaherty Road to the south. The Site lies outside of any Wetland Resource Areas and their associated 100-foot buffer zones.The Site falls entirely within the Town of North Andover municipal boundary and lies within the surface watershed of the Shawsheen River. See Figure 1, Site Locus Map. According to the Natural Resources Conservation Service (NRCS), surface soils on the Site include Ridgebury fine sandy loam and Woodbridge fine sandy loam. On-site soils are classified as Hydrologic Soil Groups (HSG) C, which is reflected in the analysis for cover types and required recharge volumes. VHB performed two (2) test pits and John Tuner Consulting performed four (4) borings in August 2024,which were used to prepare the respective soil evaluations found in Appendix C. The design infiltration rate is based on the receiving layer for future stormwater management areas. VHB's test pits found loamy sand at infiltration depth,whereas John Turner's borings found dense glacial till classified as sandy silt. Given the density of the glacial till, an infiltration rate of 0.52 inches/hr was utilized.With that, 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). 4 Stormwater Report Narrative Styiirii toir[:fieport Per the geotechnical report borings, groundwater was observed at approximately 16 feet below ground surface. To account for seasonal variations in groundwater levels,VHB performed a Frimpter adjustment to determine the estimated seasonal high groundwater table (ESHGWT). Refer to Appendix C for geotechnical investigation reports and calculations. According to the most recent FEMA Flood Insurance Rate Mapping, the Site is located in an area of minimal flood hazard (Zone X), refer to Appendix Figure 2— FEMA Firmette. IIII uuuuu uuluu�I I �I �IVm, umVlmuulumm II uuu uuum I P uuu uuum I P uuu uuum uuuupulllll� uu I The proposed project lies within the area of the Merrimack College Campus Stormwater Management Plan,which was developed in 2001 to address the future build out of the campus. The Campus Stormwater Management Plan included the development of two large extended detention areas on the campus. These detention areas have been constructed and provide capacity to address peak rates of discharge for the build-out of the campus. An Order of Conditions (DEP#090-0750)was issued for the Campus Stormwater Management Plan in 2001 by the Andover Conservation Commission. This Order provides for a peak flow rate credit system based on 100-yr storm to address the build-out of the campus, and a mechanism with the Conservation Commission to approve new developments on the campus based on these credits. A copy of the Campus Stormwater Management Plan Narrative, Original Order of Conditions (DEP#090-0750), latest issuance of amended Order of Conditions, and Peak Flow Summary are included in Appendix G. IIIIIIIIII���������IIX SIIIIII IIIIIIIII IIIIIImIIIIIII g e C oI IVI I I It I Damao I Under existing conditions, the Site is largely undeveloped lawn area generally sloping to the West. Figure 2 illustrates the existing drainage patterns on the Site. Currently, the Site is divided into one (1) drainage area as stormwater runoff flows to one (1) Design Point, which has been identified as DP-1A-1A, the closed drainage system in Lot B which is ultimately tributary to the Elm Street Basin. Table 2 below provides a summary of the existing conditions hydrologic data. Table 1 Existing Conditions Hydrologic Data Time of Design Area Curve Concentration Drainage Area Discharge Location Point (Acres) Number (min) EX-1 Existing closed system DP-1A-1A 1.0 76 6.9 in Lot B 5 Stormwater Report Narrative toirir tit I[: port IV uuuuu Ca���1111111111J 111111ti��D����Ils uuuumuum uum uuuuuuuuu Figure 3 illustrates the proposed "post construction" drainage conditions for the project.As shown, the Site will be divided into two (2) drainage areas that discharge treated stormwater to the one (1) existing Design Point. Existing drainage patterns will be maintained in accordance with the original Campus Stormwater Management Plan, and the site will continue to discharge to the Elm Street detention basin. Table 3 below provides a summary of the proposed conditions hydrologic data. Table 2 Proposed Conditions Hydrologic Data Time of Design Area Curve Concentration Drainage Area Discharge Location Point (Acres) Number (min) PR-1 Existing Closed System DP-1A-1A 0.6 92 5.0 in Lot B PR-2 Existing Closed System DP-1A-1A 0.4 78 5.0 in Lot B The site design integrates a comprehensive stormwater management system that has been developed in accordance with the Massachusetts Stormwater Handbook, Town of Andover Stormwater standards, Town of North Andover stormwater standards, and the previous Campus Stormwater Management Plan approval. The proposed Stormwater management system has been designed to meet the 0.5-inch Water Quality Volume treatment requirement but treats an excess of one inch over the site. 6 Stormwater Report Narrative \\vhb\gbl\prof\Wat-LD\11625.37 Merrimack Lecture Hall\cad\Id\Eng\Stormwater\Site Locus\1162537-Site Locus.dwg T E '�Ovhb� l rr/ rr A eYr, r l r vyrr� , e � „ r { u / r f , r rv, ✓°I� ,, 1 r � �/ k,/r r 1 ✓ o� z r P F r r A f 1� �s r a wl U r s 9 „ a , f y „ f r if r r r e v , a M � r p l , h 1 1 J �r r r, / µ, ai V I Ir i I I; / k i 1 r f, 1 , v rl i I �I y r III I" 1 i i 1 V Y" i lu iii r 1 r I I M i V 1 1 i y, i / / ry x i y 1 I, r l v r , j„ r � r Ir r f r / / r o Q� r �G r Y � r s1 r„ l ' f y ✓ 1 I 1; l V W 1: r I� I/IV r I' M 1 u�d 1 i k Y J, ri u I ' s � 1 f a i r r �1 r x o „ ry f y y I / I r. 1 1 r r , 1 4 h4: , r m r 46 1/ �.� " I �,:� r�jl /J!�y �dry,' r„ r' � /�frr✓ V: w F P I C i f 1 I r� 1 ' r rr 1 r , / J r, r / I rra� i r, 1 i o. r r ' i' / r f N V+ r „aw y / i ry I Site Locus Map Figure 1 Lecture Hall at 0 500 1000 2000 Feet Merrimack College August 26 2024 g North Andover, MA 01845 Figure 2 NationalFIRMette � Le end 7107'48"W 42040'35"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT v - Flood Elevation F ) Without Ease E E \ - �. Gl With BF€or Depth Zone AE AO,AH,v,A n \ SPECIAL FLOOD � I � Y e HAZARD AREAS Regulatory Floodw y a \ \ " .2%Annual Chance Flood Hazard,Areas \ \\ 1%annual chance flood with average \ � of depth less than one foot or with drainage - ��_ o._e._ - � areas O less an one square tulle � Future Conditions 1%Annual ZoneX a\\\\\\\\ \\\\\\\ \\ \\ Chance Flood Hazard \maIN WIN wo- y yAre with ReducedFlo Risk due to v;,v 'Alyy .- .v -v �y�y \ � o� Levee. Notes. one od e ee See \ ��\ \� OTHER AREAS OF \ � \ - FLOOD HAZARD jk o00 0° Area with Flood Risk due to Levee o e D \ vvv AreaNO SCREEN o inima Flood Hazard X .e \ \ \ \ \ Effective L4M Rs OTHER AREAS Area of Undetermined Flood Hazard Zone - GENERAL -®-- Channel,Culvert,or Storm Sewer _ \\ STRUCTURES 1 i i 1 i i 1 Levee,Dike,or Floodwall \� _ la Cross Sections with 1 Annual Chance \_ -\ 9 8 _1 All \ \ Water Surface Elevation 1 \ V 4 _ F \erg €, v \ . _ Coastal ransect \ \ Base Flood Eleva tionon Line B E) Limit of Study Jurisdiction Boundary VMS �\ \NMI'' ti\ l ine \c- _ Coastal Transect Ease N 1 011 OTHER Profile Baseline \\ - FEATURES Hydrographic Feature Digital Data Available No Digital Data Available t - ~ _ :\,� �� `� MAP PANEL \\\\ \� 3� � \\ \,\ �t _\ - \ ��` �\ �; � \��,. Unmapped —z \ \? he pin displayed on the map is an approximate pointby t snot represent selected he user and doe an authoritative property location. \ \\\ o \\ This map complies with FEMA s standards for the use of ,\ \ \ \ \\ ,\ \\� al flood m if d s low. �\ digit: ails' it is not void as described be The basemap shown complies with FEMA s basema \ \ \\ \ accuracy standards MR 10 \ - The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA.This map I, vv �k was expo on 3`2C23 at 2 30 PM and does not \ \ X —' reflect changes or amendments subsequent to this date an d t — I i p t 1, ff cha time The NFHL and effective information may nge or _ becomesuperseded by new data overtime. This map image is void if the one or more of the following map \\ elements do not appear'basemap imagery,flood zone label `\ ,� � \�� legend,S r,map C e,community\ Cale bar, creation date, Ommuni identifiers, w FIRM panel number,and FIRM effective date.Map images for Feet 1. QQ 71°7'11"W 42°4 '9"N unmapped and unmodernized areas cannot be used for 0 250 500 1,000 1,500 2,000 regulatory purposes. Basemap Imagery Source:USGS National Map 2023 \\vhb\gbl\proj\Wat-LD\11625.37 Merrimack Lecture Hall\cad\ld\Eng\Stormwater\Drainage Conditions\1162537-Drainage-EX.dwg 1 ,.,,, ,° PAR ACING LOT C 310A _ Legend SYMBOLS ---------------- DESIGN POINT AHERNE ROAD y X DRAINAGE ARE DESIGNATION POND X LINETYPES SULLIVAN HALL — DRAINAGE AREA BOUNDARY .--�---�- CONCENTRATION TIME F o� o�0000 �� FLOW LINE EX-1 g� SOIL TYPE BOUNDARY i ------- 100'BUFFER ZONE WETLAND BOUNDARY 4-220 4-219 SCS SOIL CLASSIFICATIONS v � RIDGEBURY FINE SANDY TO 3 PERCENT SLOPES LOAM,0 WOODBRIGDE FINE s s s s 31 OA SANDY LOAM,0 TO 3 PERCENT SLOPES PARKING LOT 8 a _- P -A-1 ------------- - - __ 0 _. m� Vhb Existing Drainage Conditions Figure 3 Lecture Hall Project at 0 20 40 80 Feet Merrimack College 09/11/2024 North Andover,MA \\vhb\gbl\proj\Wat-LD\11625.37 Merrimack Lecture Hall\cad\ld\Eng\Stormwater\Drainage Conditions\1162537-Drainage-PR.dwg 1 ,.,,, ,° PAR KING LOT C 310A _ Legend SYMBOLS ....... ----------------- ....................... _ � _ � DESIGN POINT AHERNE ROAD y X DRAINAGE ARE DESIGNATION i X POND 777 EN w - PROPOSED LECTURE HALL LINETYPES z SULLIVAN HALL FFE 237.0 PR-1 DRAINAGE AREA EN _ ENBOUNDARY EN = TIME OF CONCENTRATION --- --- - FLOW LINE � _ �__ SOIL TYPE BOUNDARY _ - 1 BUFFER ZONE �r 4, -z _ WETLAND BOUNDARY a fix- 4-220 4-219 \, ZSCS SOIL CLASSIFICATIONS ' P1 v I RIDGEBURY m� 1 NE SANDY LOAM, TO 3PERCENT — SLOPES- WOODBRIGDE FINE TO 3 PERCENT LOPS P ARKING LOT 8 a P ------------- I J\0 ti __ Vhb Proposed Drainage Conditions Figure 4 Lecture Hall Project at 0 20 40 80 Feet Merrimack College 09/11/2024 North Andover,MA \\vhb\qb1\pioj\Wat-LD\1 1625 37 Meiri—k Lecture H a ll\cad\ld\P Ian mic\Draiiiaqe\0ve,a11 Wate,shed Fig ure\Overal I Lm-watel shed dwy JA A a MIRM 07 1 -p M-P ,�`--K LOCATION OF HEADWALL AT ELN I I I I I 1 1 451 ANDOVER STREET K CEL "A F, i 4 PON LOCATION OF ELM STREET DETENTION BASI OUTLET CONTROL STRUCTURE 0 44A 'OSED LECTURE Hj IER DEVELOPMENT PRO, ITHIN STORMWATER 3EMENT PLAN EXTEN /I IVL),- IM"�--�6 r7crm -7 jp gz WE A 2, "s, m m c� L M a\ & —ffig W, IREET jffi100 MIAMIA % kv%10-0-1 BASIN ba-m-ft I #-p Ak' MEN Of 'C & OCATION OF FOOTBALL 11rL1 iffim m. 1361 DGE ROAD DRAINAGE a-- IF 'N0 'k FOOTBALL FIELD BASIN Legend A A AREAS WITHIN STORMWATER MANAGEMENT PLAN WATERSHED EXTENTS TRI13UTARY TO ELM STREET DETENTION BASIN AREAS WITHIN STORMWATER MANAGEMENT PLAN WATERSHED EXTENTS TRIBUTARY TO FOOTBALL FILED DETENTION BASIN AREAS WITHIN STORMWATER MANAGEMENT PLAN WATERSHED EXTENTS lbbb& CAMPUS AREA OUTSIDE OF STORMWATER MANAGEMENT PLAN Kk & WATERSHED EXTENTS APPROXIMATE DOWNSTREAM FLOW PATHS,ULTIMATELY TRIBUTARY TO SHAWSHEEN RIVER 'Ab Overall Watershed Plan Figure 5 Merrimack College Qi 0 50 100 20OFeet 315 Turnpike Street,North Andover 09/11/2024 \\vhb\gbl\prof\Wat-LD\11625.37 Merrimack Lecture Hall\cad\Id\Eng\Stormwater\SWPPP\NHESP Map\11625.37 NHESP Map.dwg ITE r a G i r F I < 1 J r ,S w a w , I � r s P C J J , " I 6 F y , r r I / r P d Kr ° ' �, •( )r 1. j J i / J / i i r I� 1 y a i y � I�I a f I m m 7 I I / I I a 7 y,. r e ti II , Y I 'r I r ry I r J / r n !1 u Ii •�� III V I y / P, I r J J; „u U 'J ,, 1 w fl ,. ✓ s sr /,J f y / i I J' J,J ip 1/ll ,n u i I r, / J I / Jr � d. f ✓ o r u l,r r, V � I C aJr v+ y r1 J � /wP b l �.," ,fw pr „i ,nr,.,r1 ✓„-, .� �. hµ 11 wl ,J/ I fd U A J I I k B� y J r- o, C a e w y� I R I ✓ / t w� �N°p ✓ `� it frr, / r I�i r rpla ' � � � , J J 1" r, I'J y t i I /J I V Y. r. i I I ,o i r , G a J' i �of / vii4g I � r r fl N v it v � J r II 4 J I / , I ' r I' / r I / J a , u r � el g , ✓ '' W, I' r w w „>f r n, Y 0 / J i / _� r� „,�u �.. w✓ l,,. � oil' 2N° e M,w r"' +� ray✓,✓a ,r,' u! ( .sa �� lle yr lu � r 6 J „✓� � s Potential Vernal Pools ` National Heritage & Figure 6 No estimated Habitats of Rare Wildlife,Priority Habitats of Rare 'Ovh�b�- Species,or Certified Vernal Pools occur in the area shown. Endangered Species M a p 315 Turnpike Street 09/10/2024 11111111111MME9 North Andover, MA NHESP data was retrieved from Office of Geographic 0 500 1000 2000 Feet Information(MassGIS),Commonwealth of Massachusetts, MasslT(August 2023) \\vhb\gbl\proj\Wat-LD\l 1625.37 Merrimack Lecture Ha11\cac1\1c1\P1anmisc\USGS\USGS Map.dwg s'— ...... .... ✓ ......... ......... ............ % N, CO f 11 34, Aii4,%, I's 1:5 N� .......... 0 I............gip,ZzN. h .............. 0 U$AF Aj fe`rri o,r i a 11 Park tk N IN N NI ............ Sa ....... ......... 7 Bw j e 0 %je M, N -N N� art 's ST 7-1111 7 41 do ............. ji�j 01 .......... 77�' N 7 tAw 1, z: 0 4L 7 j Y%V F in J all, 7 ............ % SITE :` �''� t � ,,, .,,.,.,,'1w 4�..d:";�u� � u l.. "o �"",,,` �" r,�'m w. ;, i w µ ', s �w ,. 1� "" rn , �M K , ,,j i, r 7� AF fIV T V� N M .............. 5 7, ......... 7 ij OP fop I A U01 ......... 74 ..01 J" WIN, —5i 7—t�t � JJyu m A IY ........... N1, ........... N", I —or U11) N .... 4 . . .... emy klek ........... ....... es, 5, 100 1001;, ,�F' "'� "�"��„� Iota J"u.�,.�,M..^r^d"f,�,d Pd�;a„ 1 6 fl� ��:„ Vhb USGS Map Figure 7 The Lecture Hall at Merrimack College 0 200 400 800Feet 315 Turnpike Street 09/10/2024 North Andover,MA toirir tit I[: port This page intentionally left blank. 14 Stormwater Report Narrative -to rir fir I[: p irk gVVi Regulatory Compliance I 'b� um uuuu Ilium umml uuu uuum uuu uuum i ON uuu uuum I Illm uum uuum uuu f uuuummuu PII p uuu uuum um uuuumuulll uumuul uuumuuuu uuuu uuuuumuuul uuuuuuum m'� uuuuum uuuuuuuum uuuum muuuuuuuuuSlllta��� p m pl P m m mums mul ow uuu uuum Im lour � I uu �IIIIIIIIII I uuu uuum IVuI ou I " uuu uuum I uu uuu uuum I uuullullu III uuu uuum umllUWuuunm IN As demonstrated below, the proposed Project fully complies with the DEP Stormwater Management Standards. S"'tandard '1.- No New Un"' III "'ted ��',',)iisdharges "'It 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.The proposed project will discharge reduced and treated stormwater flows to the existing piping system. 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 II ii�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, 25 and 100 years. The results of the analysis, as summarized in Table 4.1 and 4.2 below, indicate that there is no increase in peak discharge rates and volumes between the existing and proposed conditions for each of these storm events. Computations and supporting information regarding the hydrologic modeling are included in Appendix B. Table 3 Peak Discharge Rates (cfs) Design Point 2-year 10-year 25-year 100-year Design Point: DP-1A-1A Existing 1.2 2.8 3.9 5.6 Proposed 0.6 2.2 3.9 5.5 15 Regulatory Compliance -torir ateir I[:help irk Table 4 Stormwater Volume Analysis (ac-ft) Design Point 2-year 10-year 25-year 100-year Design Point: DP-1A-1A Existing 0.09 0.21 0.29 0.42 Proposed 0.07 0.20 0.28 0.42 The Campus Stormwater Management Plan approval established a credit of 62 cfs for the 100- year storm. As outlined above, the Lecture Hall project results in a net decrease in peak runoff rates for the 100-year storm, and therefore is not using the available stormwater credit. A table of all credits applied under the Campus Stormwater Management Plan is also included in Appendix G. S tandard I S tormwa ter Recharge The Project has been designed to comply with Standard 3. In accordance with the Stormwater Handbook, the Required Recharge Volume for the Project is 509 cubic feet. Recharge of stormwater has been provided through the use of a subsurface infiltration system, which has been sized using the static method. Each infiltration BMP has been designed to drain completely within 72 hours.Table 5 below provides a summary of the proposed infiltration BMPs utilized for the Project. Table 5 Summary of Recharge Calculations Bottom of Bottom of Lowest System Provided Recharge System Area System/Stone Outlet Invert Volume Infiltration BMP (square feet) Elevation (cubic feet) Subsurface Infiltration 1,097 226.5 230.0 2,943 System A Total Required Recharge 509 Total Provided Recharge 2,943 Soil evaluation (including Geotechnical Report), computations, and supporting information are included in Appendix C. tandard 4.- Wa te ii hill The Project has been designed to comply with Standard 4 and 250-23(B) of the North Andover Stormwater Management and Erosion Control Regulations. The proposed stormwater management system implements a treatment train of BMPs that has been designed to provide a minimum 90%Total Suspended Solids (TSS) removal and 60%Total 16 Regulatory Compliance -to rir fir I[:,e irk Phosphorus (TP) removal of stormwater runoff from all proposed impervious surfaces.Water quality treatment is provided subsurface infiltration chambers. Computations and supporting information are included in Appendix D.The Long-Term Pollution Prevention Plan is included under separate cover as part of the O&M Plan. S"' II II II IIIII"'' """" IIIII IIIPo"'ten"'t il ao u"'ta I "'t ��...........oads.U ��:)�;)�� s The Project is not considered a LU H PPL. S"' II IIIGril"' IIIII II °°° The Project will not discharge stormwater near or to a critical area. S ta n d a rk 0 men ts andIII ro*ec ts Sub*ec t to the S"'tandards aI "' the ten"' Ira c t il °°°° The Project is considered new development and has been designed to comply with all ten of the Stormwater Management Standards and North Andover Chapter 250 Stormwater Management and Erosion Control for a new development. Refer directly to each Standard for applicable computations and supporting information demonstrating compliance with each. S°'tandard 8: Cons°' III °' IIIII II °°°°III IIIII °' IIIII II reven°' IIIII II III III IIIII III n d S e d il m e I °'t a°' IIIII o II C o II°'tr6�s The Project will disturb approximately 1 acre of land and is therefore required to obtain coverage under the Environmental Protection Agency (EPA) National Pollutant Discharge Elimination System (NPDES) Construction General Permit. As required under this permit, a Stormwater Pollution Prevention Plan (SWPPP)will be developed and submitted before land disturbance begins. Recommended construction period pollution prevention and erosion and sedimentation controls to be finalized in the SWPPP are included in Appendix F. S°'tandard 9: Operat IIIII III and °'tenance 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 under separate cover, including the Long Term Pollution Prevention Plan. S"'tandard 101: °° III IIIII IIIII"'t ii o II o"'f ������kiiIIIII"' ��',)ilscharges Sanitary sewer and storm drainage structures which were part of the previous development on this site are to be completely removed during the site redevelopment. The design plans 17 Regulatory Compliance -to rir fir I[:,e irk submitted with this report have been designed in full compliance with current standards. The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges. A signed Illicit discharge statement is included in Appendix F. 18 Regulatory Compliance -torir heir I[:,e irk Appendix A: Standard 1 Computations and 0 Supporting Information Pipe Sizing Calculations A-1 Appendix A: Standard 1 Computations and Supporting Information -to rir fir I[:,e irk This page intentionally left blank. A-2 Appendix A: Standard 1 Computations and Supporting Information -to rir fir I[:,e irk hioo e Si��,z g C a C Lil a o s The closed drainage system was designed for the 25-year storm event, in accordance with the North Andover's stormwater management and erosion control regulations. Drainage pipes were sized using StormCAD, a HEC-22 based program. A-3 Appendix A: Standard 1 Computations and Supporting Information .100Vhb Stormcad Conduit Output Table - Hydraulic Pipe Analysis (25-yr Storm) Project Lecture Hall at Project# 11625.37 Merrimack College Calculated by AP Date 9/12/2024 Checked by DT Date 9/12/2024 Upstream Time of Manning's Capacity Velocity Rim Hydraulic Hydraulic Invert Invert Start Node Stop Node Upstream Inlet Area System CA Intensity Pipe Size Material Slope Length Flow Grade Line Rim(Lower) Grade Line Inlet C Conc. (Design) (Average) (Upper) (Upper) (Lower) In Out - - (ac) - (ac) (min) (in/hr) (in) - - (ft/ft) (ft) (cfs) (cfs) (ft/s) (ft) (ft) (ft) (ft) (ft) (ft) 101 104 0.024 0.9 0.021 5 7.94 12 HDPE Pipe 0.012 0.013 82.6 0.17 4.45 2.74 236.3 233.5 236.3 232.4 233.3 232.2 104 108 (N/A) (N/A) 0.055 5 7.71 12 HDPE Pipe 0.012 0.011 82.8 0.43 4.02 3.33 236.3 232.4 236.0 231.6 232.1 231.2 108 109 (N/A) (N/A) 0.202 5 7.52 12 HDPE Pipe 0.012 0.012 24.2 1.53 4.29 5.00 236.0 231.6 236.5 231.5 231.1 230.8 109 SYS A (N/A) (N/A) 0.412 5 7.48 12 HDPE Pipe 0.012 0.012 32.8 3.11 4.26 5.92 236.5 231.5 231.1 230.9 230.7 230.3 SYS A 110 (N/A) (N/A) 0.000 5 7.94 12 HDPE Pipe 0.012 0.014 7.3 2.30 4.52 5.78 236.5 227.7 236.5 227.5 227.0 226.9 110 111 (N/A) (N/A) 0.000 5 7.94 12 HDPE Pipe 0.012 0.01 96.1 2.30 3.94 5.21 236.5 225.7 228.0 224.6 225.0 224.0 111 EX* (N/A) (N/A) 0.000 5 7.94 24 HDPE Pipe 0.012 0.028 87.9 25.60 41.33 13.85 228.0 224.5 225.5 221.4 222.7 220.2 102 104 0.018 0.9 0.005 5 7.94 12 HDPE Pipe 0.012 0.027 15.0 0.04 6.30 2.20 236.0 233.3 236.3 232.9 233.2 232.8 105 106 0.122 0.0 0.070 5 7.94 12 HDPE Pipe 0.012 0.014 21.4 0.56 4.57 3.95 235.2 233.5 235.4 233.1 233.2 232.9 107 106 0.118 0.0 0.077 5 7.94 12 HDPE Pipe 0.012 0.011 84.4 0.62 3.98 3.68 235.4 233.7 235.4 232.8 233.4 232.5 BLDG 109 0.233 0.9 0.210 5 7.94 12 HDPE Pipe 0.012 0.011 44.6 1.68 4.09 4.95 237.0 233.6 236.5 233.0 233.0 232.5 103 1 104 1 0.040 1 0.0 1 0.029 1 5 1 7.94 1 12 HDPE Pipe 0.012 0.012 8.1 0.23 4.29 2.91 236.2 232.5 236.3 232.4 232.3 232.2 106 108 (N/A) (N/A) 0.147 5 7.76 12 HDPE Pipe 0.012 0.01 19.9 1.15 3.87 4.30 235.4 1 232.7 236.0 232.4 232.2 232.0 *EX represents the existing 24"pipe to remain.A flow of 25.6 cfs was added to Node 111 to account for upstream flows. \\vhb.com\gbl\prof\Wat-LD\11625.37 Merrimack Lecture Hall\ssheets\Stormwater\11625.37-Stormcad Conduit Output Table 1 of 1 t iirii t it I[: 1 ,irt Appendix B: 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 NOAA Atlas 14 precipitation depths for the site: 3.17, 5.02, 6.17, and 7.95 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. HydroCAD Analysis: Existing Conditions HydroCAD Analysis: Proposed Conditions 6-1 Appendix 6:Standard 2 Computations and Supporting Information t irim eit I[: p in uuuumuuuu Vummnmpul uuuuolll � uuuumuuuuu oilil uuu uuum I �� uuuumuum II uuu uuum � B-2 Appendix B:Standard 2 Computations and Supporting Information DP-1A-1AEX Lot B Drainage System EX-1 SubCat Reach Pond Link Routing Diagram for 11625.37-EX Prepared by V H B, Inc, Printed 9/11/2024 HydroCAD®10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC 11625.37 - EX Prepared by V H 6, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 3 Area Listing (all nodes) Area CN Description (sq-ft) (subcatchment-numbers) 39,400 74 >75% Grass cover, Good, HSG C (EX-1) 31150 98 Paved parking (EX-1) 42,550 76 TOTAL AREA S-tormwater[:eport 2...........Yea r S torm t .................... �,�,:,X III ii n 9 B-3 Appendix B:Standard 2 Computations and Supporting Information 11625.37 - EX Type 111 24-hr 2-Year Rainfall=3.17" Prepared by VH B, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment EX-1: EX-1 Runoff = 1.2 cfs @ 12.11 hrs, Volume= 4,011 cf, Depth= 1.13" Routed to Link DP-1 A-1 A : Lot B Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.17" Area (sf) CN Description 39,400 74 >75% Grass cover, Good, HSG C 3,150 98 Paved parking 421550 76 Weighted Average 391400 92.60% Pervious Area 3,150 7.40% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 50 0.0150 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.16" 0.5 115 0.0500 3.60 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 6.9 165 Total Summary for Link DP-1A-1A: Lot B Drainage System Inflow Area = 42,550 sf, 7.40% Impervious, Inflow Depth = 1.13" for 2-Year event Inflow = 1.2 cfs @ 12.11 hrs, Volume= 43011 cf Primary = 1.2 cfs @ 12.11 hrs, Volume= 4,011 cf, Atten= 0%, Lag= 0.0 min Routed to nonexistent node DP-2 Primary outflow = Inflow, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs S-tormwater[:eport 10...........Yea r S III II t .................... X ii S t iIII II g B-4 Appendix B:Standard 2 Computations and Supporting Information 11625.37 - EX Type 111 24-hr 10-Year Rainfall=5.02" Prepared by VH B, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment EX-1: EX-1 Runoff = 2.8 cfs @ 12.10 hrs, Volume= 9,049 cf, Depth= 2.55" Routed to Link DP-1 A-1 A : Lot B Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=5.02" Area (sf) CN Description 39,400 74 >75% Grass cover, Good, HSG C 3,150 98 Paved parking 421550 76 Weighted Average 391400 92.60% Pervious Area 3,150 7.40% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 50 0.0150 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.16" 0.5 115 0.0500 3.60 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 6.9 165 Total Summary for Link DP-1A-1A: Lot B Drainage System Inflow Area = 42,550 sf, 7.40% Impervious, Inflow Depth = 2.55" for 10-Year event Inflow = 2.8 cfs @ 12.10 hrs, Volume= 9,049 cf Primary = 2.8 cfs @ 12.10 hrs, Volume= 9,049 cf, Atten= 0%, Lag= 0.0 min Routed to nonexistent node DP-2 Primary outflow = Inflow, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs S-tormwater[:eport 25...........Yea r S III II IIIIIS t IIIII II g B-5 Appendix B:Standard 2 Computations and Supporting Information 11625.37 - EX Type/1/ 24-hr 25-Year Rainfall=6.17" Prepared by VH B, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 7 Summary for Subcatchment EX-1: EX-1 Runoff = 3.9 cfs @ 12.10 hrs, Volume= 12,507 cf, Depth= 3.53" Routed to Link DP-1 A-1 A : Lot B Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-Year Rainfall=6.17" Area (sf) CN Description 39,400 74 >75% Grass cover, Good, HSG C 3,150 98 Paved parking 421550 76 Weighted Average 391400 92.60% Pervious Area 3,150 7.40% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 50 0.0150 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.16" 0.5 115 0.0500 3.60 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 6.9 165 Total Summary for Link DP-1A-1A: Lot B Drainage System Inflow Area = 42,550 sf, 7.40% Impervious, Inflow Depth = 3.53" for 25-Year event Inflow = 3.9 cfs @ 12.10 hrs, Volume= 12,507 cf Primary = 3.9 cfs @ 12.10 hrs, Volume= 12,507 cf, Atten= 0%, Lag= 0.0 min Routed to nonexistent node DP-2 Primary outflow = Inflow, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs S-tormwater[:eport 100...........Yea r S torm t .................... ii�S t IIIII n g B-6 Appendix B:Standard 2 Computations and Supporting Information 11625.37 - EX Type 111 24-hr 100-Year Rainfall=7.95" Prepared by VH B, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment EX-1: EX-1 Runoff = 5.6 cfs @ 12.10 hrs, Volume= 18,128 cf, Depth= 5.11" Routed to Link DP-1 A-1 A : Lot B Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=7.95" Area (sf) CN Description 39,400 74 >75% Grass cover, Good, HSG C 3,150 98 Paved parking 421550 76 Weighted Average 391400 92.60% Pervious Area 3,150 7.40% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 50 0.0150 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.16" 0.5 115 0.0500 3.60 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 6.9 165 Total Summary for Link DP-1A-1A: Lot B Drainage System Inflow Area = 42,550 sf, 7.40% Impervious, Inflow Depth = 5.11" for 100-Year event Inflow = 5.6 cfs @ 12.10 hrs, Volume= 18,128 cf Primary = 5.6 cfs @ 12.10 hrs, Volume= 18,128 cf, Atten= 0%, Lag= 0.0 min Routed to nonexistent node DP-2 Primary outflow = Inflow, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs t irim eit I[: p in uuuuumuuu I uuummVll I uumm IlVlummmuu� I uuu uuum uumummpm uuuuuuu uuum uuuuu puu u B-7 Appendix B:Standard 2 Computations and Supporting Information DP-1 A-1 A A Pi PR 1 Lot B Drainage Syste StormTrap ST2 Single PR-1 5-0 PR-2 PR-2 SubCat Reach Pond Link Routing Diagram for 11625.37-PR Prepared by V H B, Inc, Printed 9/11/2024 HydroCAD®10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC 11625.37 - PR Prepared by V H B, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 3 Area Listing (all nodes) Area CN Description (sq-ft) (subcatchment-numbers) 217200 74 >75% Grass cover, Good, HSG C (PR 1, PR-2) 117200 98 Paved parking, HSG C (PR 1, PR-2) 107150 98 Roof (PR 1) 42,550 86 TOTAL AREA S-tormwater[:eport 2 III S torm roposed B-8 Appendix B:Standard 2 Computations and Supporting Information 11625.37 - PR Type /// 24-hr 2-Year Rainfall=3.17" Prepared by VHB, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment PR 1: PR-1 Runoff = 1.5 cfs @ 12.07 hrs, Volume= 4,693 cf, Depth= 2.32" Routed to Pond P1 : StormTrap ST2 Single 5-0 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.17" Area (sf) CN Description 5,600 74 >75% Grass cover, Good, HSG C 101150 98 Roof 8,500 98 Paved parking, HSG C 241250 92 Weighted Average 5,600 23.09% Pervious Area 18,650 76.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.8 50 0.0140 1.03 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.16" 1.8 220 0.1400 2.01 1.58 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.110 2.6 270 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment PR-2: PR-2 Runoff = 0.6 cfs @ 12.08 hrs, Volume= 1,908 cf, Depth= 1.25" Routed to Link DP-1 A-1 A : Lot B Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.17" Area (sf) CN Description 151600 74 >75% Grass cover, Good, HSG C 2,700 98 Paved parking, HSG C 181300 78 Weighted Average 151600 85.25% Pervious Area 2,700 14.75% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.1 50 0.0900 0.27 Sheet Flow, Grass: Short n= 0.150 P2= 3.16" 0.1 20 0.1500 6.24 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 3.2 70 Total, Increased to minimum Tc = 5.0 min 11625.37 - PR Type /// 24-hr 2-Year Rainfall=3.17" Prepared by VH B, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 6 Summary for Pond P1: StormTrap ST2 Single 5-0 Inflow Area = 24,250 sf, 76.91% Impervious, Inflow Depth = 2.32" for 2-Year event Inflow = 1.5 cfs @ 12.07 hrs, Volume= 4,693 cf Outflow = 0.1 cfs @ 13.92 hrs, Volume= 2,299 cf, Atten= 94%, Lag= 110.6 min Discarded = 0.0 cfs @ 8.47 hrs, Volume= 1,365 cf Primary = 0.1 cfs @ 13.92 hrs, Volume= 933 cf Routed to Link DP-1 A-1 A : Lot B Drainage System Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Peak Elev= 230.13'@ 13.92 hrs Surf.Area= 1,097 sf Storage= 3,063 cf Plug-Flow detention time=481.9 min calculated for 2,299 cf(49% of inflow) Center-of-Mass det. time= 368.2 min ( 1,165.4 - 797.2 ) Volume Invert Avail.Storage Storage Description #1 A 226.50' 518 cf 23.79'W x 46.10'L x 6.00'H Field A 6,581 cf Overall - 5,286 cf Embedded = 1,295 cf x 40.0% Voids #2A 227.00' 4,215 cf StormTrap SingleTrap 5-0x 2 Inside #1 Inside= 101.7"W x 60.0"H => 38.33 sf x 15.40'L = 590.2 cf Outside= 101.7"W x 66.0"H => 46.64 sf x 15.401 = 718.0 cf 8.48' x 30.79' Core + 6.66' Border = 21.79' x 44.10' System #3 227.50' 88 cf 4.00'D x 7.00'H Vertical Cone/CylindeFimpervious 4,821 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 226.50' 0.520 in/hr Exfiltration over Surface area #2 Primary 225.00' 12.0" Round Culvert L= 5.0' RCP, square edge headwall, Ke= 0.500 Inlet/ Outlet Invert= 225.00'/224.90' S= 0.0200 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #3 Device 2 230.00' 10.0"Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Device 2 231.50' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) Discarded OutFlow Max=0.0 cfs @ 8.47 hrs HW=226.58' (Free Discharge) L1=Exfi1tration (Exfiltration Controls 0.0 cfs) Primary OutFlow Max=0.1 cfs @ 13.92 hrs HW=230.13' (Free Discharge) L2=Culvert (Passes 0.1 cfs of 8.1 cfs potential flow) 3=Orifice/Grate (Orifice Controls 0.1 cfs @ 1.24 fps) 4=Sharp-Crested Rectangular Weir( Controls 0.0 cfs) Summary for Link DP-1A-1A: Lot B Drainage System Inflow Area = 42,550 sf, 50.18% Impervious, Inflow Depth = 0.80" for 2-Year event Inflow = 0.6 cfs @ 12.08 hrs, Volume= 2,842 cf Primary = 0.6 cfs @ 12.08 hrs, Volume= 2,842 cf, Atten= 0%, Lag= 0.0 min Routed to nonexistent node DP-2 11625.37 - PR Type 11124-hr 2-Year Rainfall=3.17" Prepared by VHB, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 7 Primary outflow = Inflow, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs S-tormwater[:eport 10...........Yea r S torm roposed B-9 Appendix B:Standard 2 Computations and Supporting Information 11625.37 - PR Type /// 24-hr 10-Year Rainfall=5.02" Prepared by VHB, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment PR 1: PR-1 Runoff = 2.6 cfs @ 12.07 hrs, Volume= 8,303 cf, Depth= 4.11" Routed to Pond P1 : StormTrap ST2 Single 5-0 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=5.02" Area (sf) CN Description 5,600 74 >75% Grass cover, Good, HSG C 101150 98 Roof 8,500 98 Paved parking, HSG C 241250 92 Weighted Average 5,600 23.09% Pervious Area 18,650 76.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.8 50 0.0140 1.03 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.16" 1.8 220 0.1400 2.01 1.58 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.110 2.6 270 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment PR-2: PR-2 Runoff = 1.4 cfs @ 12.08 hrs, Volume= 4,161 cf, Depth= 2.73" Routed to Link DP-1 A-1 A : Lot B Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=5.02" Area (sf) CN Description 151600 74 >75% Grass cover, Good, HSG C 2,700 98 Paved parking, HSG C 181300 78 Weighted Average 151600 85.25% Pervious Area 2,700 14.75% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.1 50 0.0900 0.27 Sheet Flow, Grass: Short n= 0.150 P2= 3.16" 0.1 20 0.1500 6.24 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 3.2 70 Total, Increased to minimum Tc = 5.0 min 11625.37 - PR Type /// 24-hr 10-Year Rainfall=5.02" Prepared by VH B, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 9 Summary for Pond P1: StormTrap ST2 Single 5-0 Inflow Area = 24,250 sf, 76.91% Impervious, Inflow Depth = 4.11" for 10-Year event Inflow = 2.6 cfs @ 12.07 hrs, Volume= 8,303 cf Outflow = 1.3 cfs @ 12.20 hrs, Volume= 5,897 cf, Atten= 49%, Lag= 7.5 min Discarded = 0.0 cfs @ 6.50 hrs, Volume= 1,460 cf Primary = 1.3 cfs @ 12.20 hrs, Volume= 4,437 cf Routed to Link DP-1 A-1 A : Lot B Drainage System Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Peak Elev= 230.67'@ 12.20 hrs Surf.Area= 1,097 sf Storage= 3,556 cf Plug-Flow detention time=257.7 min calculated for 5,897 cf(71% of inflow) Center-of-Mass det. time= 167.1 min ( 948.7 - 781.7 ) Volume Invert Avail.Storage Storage Description #1 A 226.50' 518 cf 23.79'W x 46.10'L x 6.00'H Field A 6,581 cf Overall - 5,286 cf Embedded = 1,295 cf x 40.0% Voids #2A 227.00' 4,215 cf StormTrap SingleTrap 5-0x 2 Inside #1 Inside= 101.7"W x 60.0"H => 38.33 sf x 15.40'L = 590.2 cf Outside= 101.7"W x 66.0"H => 46.64 sf x 15.401 = 718.0 cf 8.48' x 30.79' Core + 6.66' Border = 21.79' x 44.10' System #3 227.50' 88 cf 4.00'D x 7.00'H Vertical Cone/CylindeFimpervious 4,821 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 226.50' 0.520 in/hr Exfiltration over Surface area #2 Primary 225.00' 12.0" Round Culvert L= 5.0' RCP, square edge headwall, Ke= 0.500 Inlet/ Outlet Invert= 225.00'/224.90' S= 0.0200 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #3 Device 2 230.00' 10.0"Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Device 2 231.50' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) Discarded OutFlow Max=0.0 cfs @ 6.50 hrs HW=226.58' (Free Discharge) L1=Exfi1tration (Exfiltration Controls 0.0 cfs) Primary OutFlow Max=1.3 cfs @ 12.20 hrs HW=230.67' (Free Discharge) L2=Culvert (Passes 1.3 cfs of 8.6 cfs potential flow) 3=Orifice/Grate (Orifice Controls 1.3 cfs @ 2.79 fps) 4=Sharp-Crested Rectangular Weir( Controls 0.0 cfs) Summary for Link DP-1A-1A: Lot B Drainage System Inflow Area = 42,550 sf, 50.18% Impervious, Inflow Depth = 2.42" for 10-Year event Inflow = 2.2 cfs @ 12.15 hrs, Volume= 8,598 cf Primary = 2.2 cfs @ 12.15 hrs, Volume= 8,598 cf, Atten= 0%, Lag= 0.0 min Routed to nonexistent node DP-2 11625.37 - PR Type /// 24-hr 10-Year Rainfall=5.02" Prepared by VHB, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 10 Primary outflow = Inflow, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs S-tormwater[: port 25 -Yea r S torm t .................... �Plroposed 6-10 Appendix B:Standard 2 Computations and Supporting Information 11625.37 - PR Type /// 24-hr 25-Year Rainfall=6.17" Prepared by VHB, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment PR 1: PR-1 Runoff = 3.3 cfs @ 12.07 hrs, Volume= 10,582 cf, Depth= 5.24" Routed to Pond P1 : StormTrap ST2 Single 5-0 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-Year Rainfall=6.17" Area (sf) CN Description 5,600 74 >75% Grass cover, Good, HSG C 101150 98 Roof 8,500 98 Paved parking, HSG C 241250 92 Weighted Average 5,600 23.09% Pervious Area 18,650 76.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.8 50 0.0140 1.03 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.16" 1.8 220 0.1400 2.01 1.58 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.110 2.6 270 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment PR-2: PR-2 Runoff = 1.9 cfs @ 12.07 hrs, Volume= 5,687 cf, Depth= 3.73" Routed to Link DP-1 A-1 A : Lot B Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-Year Rainfall=6.17" Area (sf) CN Description 151600 74 >75% Grass cover, Good, HSG C 2,700 98 Paved parking, HSG C 181300 78 Weighted Average 151600 85.25% Pervious Area 2,700 14.75% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.1 50 0.0900 0.27 Sheet Flow, Grass: Short n= 0.150 P2= 3.16" 0.1 20 0.1500 6.24 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 3.2 70 Total, Increased to minimum Tc = 5.0 min 11625.37 - PR Type /// 24-hr 25-Year Rainfall=6.17" Prepared by VH B, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 12 Summary for Pond P1: StormTrap ST2 Single 5-0 Inflow Area = 24,250 sf, 76.91% Impervious, Inflow Depth = 5.24" for 25-Year event Inflow = 3.3 cfs @ 12.07 hrs, Volume= 10,582 cf Outflow = 2.2 cfs @ 12.15 hrs, Volume= 8,171 cf, Atten= 33%, Lag= 4.8 min Discarded = 0.0 cfs @ 5.48 hrs, Volume= 1,500 cf Primary = 2.2 cfs @ 12.15 hrs, Volume= 6,670 cf Routed to Link DP-1 A-1 A : Lot B Drainage System Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Peak Elev= 231.12'@ 12.15 hrs Surf.Area= 1,097 sf Storage= 3,966 cf Plug-Flow detention time=212.3 min calculated for 8,171 cf(77% of inflow) Center-of-Mass det. time= 131.5 min ( 906.9 - 775.4 ) Volume Invert Avail.Storage Storage Description #1 A 226.50' 518 cf 23.79'W x 46.10'L x 6.00'H Field A 6,581 cf Overall - 5,286 cf Embedded = 1,295 cf x 40.0% Voids #2A 227.00' 4,215 cf StormTrap SingleTrap 5-0x 2 Inside #1 Inside= 101.7"W x 60.0"H => 38.33 sf x 15.40'L = 590.2 cf Outside= 101.7"W x 66.0"H => 46.64 sf x 15.401 = 718.0 cf 8.48' x 30.79' Core + 6.66' Border = 21.79' x 44.10' System #3 227.50' 88 cf 4.00'D x 7.00'H Vertical Cone/CylindeFimpervious 4,821 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 226.50' 0.520 in/hr Exfiltration over Surface area #2 Primary 225.00' 12.0" Round Culvert L= 5.0' RCP, square edge headwall, Ke= 0.500 Inlet/ Outlet Invert= 225.00'/224.90' S= 0.0200 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #3 Device 2 230.00' 10.0"Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Device 2 231.50' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) Discarded OutFlow Max=0.0 cfs @ 5.48 hrs HW=226.58' (Free Discharge) L1=Exfi1tration (Exfiltration Controls 0.0 cfs) Primary OutFlow Max=2.2 cfs @ 12.15 hrs HW=231.12' (Free Discharge) L2=Culvert (Passes 2.2 cfs of 9.0 cfs potential flow) 3=Orifice/Grate (Orifice Controls 2.2 cfs @ 4.05 fps) 4=Sharp-Crested Rectangular Weir( Controls 0.0 cfs) Summary for Link DP-1A-1A: Lot B Drainage System Inflow Area = 42,550 sf, 50.18% Impervious, Inflow Depth = 3.49" for 25-Year event Inflow = 3.8 cfs @ 12.10 hrs, Volume= 12,358 cf Primary = 3.8 cfs @ 12.10 hrs, Volume= 12,358 cf, Atten= 0%, Lag= 0.0 min Routed to nonexistent node DP-2 11625.37 - PR Type /// 24-hr 25-Year Rainfall=6.17" Prepared by VHB, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 13 Primary outflow = Inflow, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs S-tormwater[:�eport 100...........Yea r III II IIt .................... �Pl ro p o s e d B-11 Appendix B:Standard 2 Computations and Supporting Information 11625.37 - PR Type /// 24-hr 100-Year Rainfall=7.95" Prepared by VHB, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment PR 1: PR-1 Runoff = 4.4 cfs @ 12.07 hrs, Volume= 14,134 cf, Depth= 6.99" Routed to Pond P1 : StormTrap ST2 Single 5-0 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=7.95" Area (sf) CN Description 5,600 74 >75% Grass cover, Good, HSG C 101150 98 Roof 8,500 98 Paved parking, HSG C 241250 92 Weighted Average 5,600 23.09% Pervious Area 18,650 76.91% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.8 50 0.0140 1.03 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.16" 1.8 220 0.1400 2.01 1.58 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.110 2.6 270 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment PR-2: PR-2 Runoff = 2.7 cfs @ 12.07 hrs, Volume= 8,151 cf, Depth= 5.34" Routed to Link DP-1 A-1 A : Lot B Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=7.95" Area (sf) CN Description 151600 74 >75% Grass cover, Good, HSG C 2,700 98 Paved parking, HSG C 181300 78 Weighted Average 151600 85.25% Pervious Area 2,700 14.75% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.1 50 0.0900 0.27 Sheet Flow, Grass: Short n= 0.150 P2= 3.16" 0.1 20 0.1500 6.24 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 3.2 70 Total, Increased to minimum Tc = 5.0 min 11625.37 - PR Type /// 24-hr 100-Year Rainfall=7.95" Prepared by VH B, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 15 Summary for Pond P1: StormTrap ST2 Single 5-0 Inflow Area = 24,250 sf, 76.91% Impervious, Inflow Depth = 6.99" for 100-Year event Inflow = 4.4 cfs @ 12.07 hrs, Volume= 14,134 cf Outflow = 3.3 cfs @ 12.13 hrs, Volume= 11,715 cf, Atten= 25%, Lag= 3.8 min Discarded = 0.0 cfs @ 4.36 hrs, Volume= 1,543 cf Primary = 3.3 cfs @ 12.13 hrs, Volume= 10,173 cf Routed to Link DP-1 A-1 A : Lot B Drainage System Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Peak Elev= 231.60'@ 12.13 hrs Surf.Area= 1,097 sf Storage= 4,397 cf Plug-Flow detention time= 174.1 min calculated for 11,715 cf(83% of inflow) Center-of-Mass det. time= 104.9 min ( 873.2 - 768.3 ) Volume Invert Avail.Storage Storage Description #1 A 226.50' 518 cf 23.79'W x 46.10'L x 6.00'H Field A 6,581 cf Overall - 5,286 cf Embedded = 1,295 cf x 40.0% Voids #2A 227.00' 4,215 cf StormTrap SingleTrap 5-0x 2 Inside #1 Inside= 101.7"W x 60.0"H => 38.33 sf x 15.40'L = 590.2 cf Outside= 101.7"W x 66.0"H => 46.64 sf x 15.401 = 718.0 cf 8.48' x 30.79' Core + 6.66' Border = 21.79' x 44.10' System #3 227.50' 88 cf 4.00'D x 7.00'H Vertical Cone/CylindeFimpervious 4,821 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 226.50' 0.520 in/hr Exfiltration over Surface area #2 Primary 225.00' 12.0" Round Culvert L= 5.0' RCP, square edge headwall, Ke= 0.500 Inlet/ Outlet Invert= 225.00'/224.90' S= 0.0200 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #3 Device 2 230.00' 10.0"Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Device 2 231.50' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) Discarded OutFlow Max=0.0 cfs @ 4.36 hrs HW=226.58' (Free Discharge) L1=Exfi1tration (Exfiltration Controls 0.0 cfs) Primary OutFlow Max=3.2 cfs @ 12.13 hrs HW=231.60' (Free Discharge) L2=Culvert (Passes 3.2 cfs of 9.3 cfs potential flow) 3=Orifice/Grate (Orifice Controls 2.9 cfs @ 5.23 fps) 4=Sharp-Crested Rectangular Weir(Weir Controls 0.4 cfs @ 1.02 fps) Summary for Link DP-1A-1A: Lot B Drainage System Inflow Area = 42,550 sf, 50.18% Impervious, Inflow Depth = 5.17" for 100-Year event Inflow = 5.5 cfs @ 12.12 hrs, Volume= 18,323 cf Primary = 5.5 cfs @ 12.12 hrs, Volume= 18,323 cf, Atten= 0%, Lag= 0.0 min Routed to nonexistent node DP-2 11625.37 - PR Type /// 24-hr 100-Year Rainfall=7.95" Prepared by VHB, Inc Printed 9/11/2024 HydroCAD® 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Page 16 Primary outflow = Inflow, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs t irir tit I[: port This page intentionally left blank. 6-12 Appendix 6:Standard 2 Computations and Supporting Information t trim eit I[: Ip in Appendix C: Standard 3 Computations and 0 Supporting Documentation Soil Evaluation in accordance with Volume 3, Chapter 1 of the Handbook Recharge Volume Calculations and Drawdown Analysis HydroCAD Staged Storage Areas C-1 Appendix C:Standard 3 Computations and Supporting Documentation t irim eit I[: p in uuuumuuum i uuu uuum i �i„ i So uuuuuuuupm C-2 Appendix C:Standard 3 Computations and Supporting Documentation Hydrologic Soil Group—Essex County, Massachusetts, Northern Part O N ,--1 n n ° ° 325640 325710 325780 325850 325920 325990 326060 326130 326200 326270 420 40'21"N v�, — 42 40 21 N \ I� rR t v, a s,, 4 s 420 40'T N y, �, � �� 420 40'T N 325640 325710 325780 325850 325920 325990 326060 326130 326200 326270 O N Map Scale:1:2,960 if printed on A landscape(11"x 8.5")sheet. Meters °� N 0 40 80 160 240 Feet 0 100 200 400 600 Map projection:Web Mercator Comer coordinates:WGS84 Edge tics:UTM Zone 19N WGS84 usDA Natural Resources Web Soil Survey 9/6/2024 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 19,Sep 10,2023 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: Mar 1,2023—Sep 1, Soil Rating Points 2023 13 q The orthophoto or other base map on which the soil lines were 13 compiled and digitized probably differs from the background A/D compiled 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 9/6/2024 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 9.3 21.3% loam,0 to 3 percent slopes 72A Whitman fine sandy D 3.2 7.3% loam,0 to 3 percent slopes 310A Woodbridge fine sandy C/D 31.0 71.2% loam,0 to 3 percent slopes 311 B Woodbridge fine sandy C/D 0.1 0.2% loam,0 to 8 percent slopes,very stony Totals for Area of Interest 43.6 100.0% USDA Natural Resources Web Soil Survey 9/6/2024 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 9/6/2024 Conservation Service National Cooperative Soil Survey Page 4 of 4 JOHN TURN E R JTC Project N o: 24-04-085.01 CO NSU LIT I N G AA August 22, 2024 IIIIIIIVum uuuuuuuumuOuuuNuu m uuuuuu III q II I llll � uuuuuuuuuuuuuuuuuuuuuuum ��11111111111111) uuuuu1111111111111111111111111111111 uuuuuuumm �I4m m m � m m I (-.11 I m [I'll II m PROPOSED LECTURE HALL 315 TURNPIKE STREET NORTH ANDOVER, MASSACHUSETTS Prepared for: Merrimack College 315 Turnpike Street North Andover, Massachusetts 01845 Prepared by: John Turner Consulting, Inc. Construction Engineering& Inspection I Environmental Consulting I Geotechnical Engineering Materials Testing I Special Inspections I Building Sciences I Pavement Consulting I Sustainability and Energy Services www.consultjtc.com ��EOTECHN|CAL EN��|NEER|N�� REPORT n�����M�� �*�� ��(")i �������� ��3�����U���������������U��� � August 22' 2O24 Allison Gill Merrimack College 315Turnpike Street North Andover, MessachusettsOl845 E: RE: Geotechnica| Engineering Report Proposed Lecture Hall 315Turnpike Street North Andover, Massachusetts Dear Ms. Gill: John Turner Consulting, Inc. (JT[) is pleased to present this Geotechnica| Engineering Report for the above captioned project.The purpose of our services was to obtain information on the subsurface conditions at the site and to provide gectechnice| engineering recommendations to support the planning, design' and construction of the proposed development. JTC conducted geotechnical services in general accordance with our approved contract.This report summarizes the findings from our investigation and provides ourgectechnica| recommendations regarding the design and construction of the proposed project. This report completes our scope of services under the approved contract. We appreciate the opportunity to assist you on this project and look forward to working with you through its completion. Please do not hesitate to contact us if you have any questions or require additional information. Respectfully, ]OHN TURNER[ONSULT|NG, INC. Quentyn Gug|ie|mo' PE Stephen C. Lenne' PE SeniorGeotechnica| Engineer Vice President of Engineering P: 831.578.6620 P: 413.222.1675 E: E� OF � JOHN TURNER, �� cumumo/wa ��EOTECHN|CAL EN��|NEER|N�� REPORT n�����M�� �*�����(")i ������� 3�����U���������������U��� � B1111, N �� �� �� � ���1TE����� �=� �_ �=���� �� 1.0 PROJECT INFORMATION .......................................................................................................... l 1.1 Site Description.................................................................................................................................l 1.2 Proposed Development ....................................................................................................................2 2.0 GEOTECHN|CAL EXPLORATIONS .............................................................................................. 3 3.0 SUBSURFACE CONDITIONS...................................................................................................... 4 3.1 Typical Subsurface Profile.................................................................................................................4 3.2 Groundwater.....................................................................................................................................4 4.0 EARTHWORK............................................................................................................................ G 4.1 Site Preparation ................................................................................................................................6 4.2 Fill Materials......................................................................................................................................G 4.3 Re-Use of Site Soils............................................................................................................................7 5.0 Foundations............................................................................................................................. 8 5.1 FoundstionDesignRecommendadons -------------------------------O 5.2 Foundation Subgr dePreperation---------------------------------.O 5.3 Seismic Considerations .....................................................................................................................9 5.4 S|ab'Dn-Grade...................................................................................................................................9 6.0 CLOSING................................................................................................................................. lO APPENDICES: APPENDIX A: Site Plan & Exploration Location Plan APPENDIX 8: Exploration Logs & Key to Symbols and Descriptions APPENDIX C: Site Photographs APPENDIX D:Additional Earthwork Recommendations APPENDIX E ASFE Geotechnica| Engineering Report Information APPENDIX F: Limitations OF � JOHN TURNER, cumumo/wa �~ WWW.comsuLTJTccoM I),411)r I�)j GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifill"I 2,1!1 0,,!!1 "I'di'D��l 1 11 .......... ... .......... Nil, 1111II,jjSI&" 111111�11 clgtist' 02111!, (D (D S E D E I ..........I [.' 111��� I Pill I D 0 11111!1�'C�...........���U S E.............S 111111II L 3,,1 5 P11111111 1.0 110 J E C T IIIIIII il 0 11, N�111 To complete our work,JTC referenced the following information that you provided: • Schematic Floor Plans, by Procon, Sheet No. 3 through 9, dated 3-21-24; • Test Pit and Boring Locations Site Plan, by VHB, Sheet No. 1 through 3, dated 7-24-24; • Aerial photographs and surficial geologic maps of the area. 1.1 Site Description The following table summarizes our understanding of the existing site: Location 315 Turnpike Street, North Andover, Massachusetts Lot Size 0.67 acres Existing Improvements Landscaped area Grass Lawns Current Ground Cover Moderate tree cover Topography Relatively Flat Regional Geology 1 Glacial Till over shallow bedrock 1. Likely native soils based on local, publicly available surficial geology map mr JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM I PAGE 1 OF 10 I),411)r I�)J GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifill"I .2,1!1 0,,!!1 "I'di'D��l 1 11 .......... ... .......... Nil, 1111II,ilsl&" 111111�11 clgtist' 02111!, (D (D S E D E I ..........I [.' 111 1"') 1 Pill I D 0 11111!1�'C�...........���U S E.............S 111111II L 3,,1 5 P11111111 E 1.2 Proposed Development The following table summarizes our understanding of the project: Structure Two-story educational building Size 9,600 square feet (sf) Finished Floor Elevation (El) = 236 feet (approximate) Strip footings: 2 to 3 kips per linear foot (klf) (assumed) Loads Column Footings: 100 kips (assumed) Slab-on-grade: 125 pounds per square foot (psf) (assumed) Basement No basement Cut/Fill - Building Cuts: Up to 2 feet Fill: N/A Cut/Fill -Site Cuts: Up to 2 feet Fill: N/A Retaining Walls N/A Slopes N/A Pavements N/A Drainage Areas N/A Mr JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM PAGE 2 OF 10 I),411)r�l I�)j GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifill"I 2,1!1 0,,!!1 "I'di'D�1 1 .......... ... .......... Nil, 1111II,jjSI&" 111111�11 clgtist' 02111!, (D (D S E D E I ..........I [.' 111��� I Pill I D 0 11111!1�'C�...........U S E.............S 111111II L 3,,1 5 P11111111 �11(11'II IS 2.0 G 1 1 311 T C 11,111,111,11 P�111 I""Ill ii k, E 111 11111111�I, Wil 6wil The following table summarizes the field exploration program performed at the site: Soil Borings Dates 8/7/24 Drilling Contractor Seaboard Drilling, LLC Drilling Rig ATV-mounted Auto-Hammer Number of Borings 41 TB-1 through TB-4 Boring Depth Range 11 to 16.5 feet below ground surface (bgs) Drilling Method 4Y4-inch internal diameter hollow stem augers (HSA) Sampling Method Standard Penetration Tests (SPTs) 2-inch outside diameter split-spoon samplers Additional Services N/A The attached Exploration Location Plan depicts the approximate locations of the explorations. JTC directed the explorations,field testing, and sampling activities and logged the subsurface conditions encountered at each exploration location. Soil samples were sealed in moisture-tight containers and returned to JTC's office for further review, classification, and/or geotechnical laboratory testing.The explorations were backfilled with spoils prior to departing the site. mr JOHNTURNER, COIN SU LT I N�G WWW.CONSULTJTC.COM PAGE 3 OF 10 ��EOTECHN|CAL EN(�|NEER|N�� REPORT ��Pr������ ���v����� �����������������U����� �������������� ����� �.0 S�1������� �E C 0 P�il I T 0 P�il IS, 3~1 Typical Subsurface Profile The following table provides a general summary description of the typical subsurface conditions encountered in the explorations. Detailed descriptions of the conditions observed at each exploration are provided in the appendix Exp/onobonLogs. Surface With l Materials Brown Silty Sand SM O 0.8to2 Loose organics (Topsoil) Z Fill (TB-2 only) Tan Silty Sand SM Z 5 Loose Bottom of Dense to 3 Glacial Till Tan/Gray ��L O.��o5 Very With gravel ' - borings Dense Bedrock was not encountered in the explorations. 4 Bedrock N/A N/A N/A N/A N/A N/A 3~2 Groundwater The following table provides a summary description of the observed groundwater levels encountered in the explorations. Detailed descriptions of the conditions observed at each exploration are provided in the appendix Exp/onztionLogs. TB-1 N/A N/A N/A TB-2 N/A N/A N/A TB-3 N/A N/A N/A Open borehole, while TB-4 lG 219.5 drilling, possible perched water Groundwater level observations made at the time of the explorations should be considered approximate. JTC estimates that this investigation occurred during a period of seasonally normal ground water levels. Fluctuations in groundwater level should be expected to occur because ofseasonal rainfall variations, runoff, grade adjustments on and around the site, as well as surrounding drainage improvements, and other factors. mr � JOHNTURNER, �� cumsu^r/wa I),411)r I�)J GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifill"I 2,1!1 0,,!!1 "I'di'D��l 1 11 .......... ... .......... Nil, 1111II,JJSI&" 111111�11 clgtist' 02111!, (D (D S E D E I ..........I [.' 111��� I Pill I D 0 11111!1�'C�...........���U S E.............S 111111II L 3,,1 5 P11111111 Water may also become temporarily perched over low permeability soils or bedrock. The possibility of groundwater level fluctuations should be considered when developing the design and construction plans for the project. Mr JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM PAGE 5 OF 10 ��EOTECHN|CAL EN(�|NEER|N�� REPORT ��Pr������ ���v����� �����������������U����� �������������� ����� 4.0 T���111111111111'w 0�� � Earthwork recommendations apply to site earthwork and subgrade preparation for foundations, slabs-on- grade, pavements, and retaining walls. � See the appendix Additional Eorthwork Recommendations for additional guidance. 4~1 S"Ite Preparation � The Gecdechnica| Engineer should directly observe key subgrede preparation and earthwork. At a minimum, the Geotechnica| Engineer should observe: — removal of unsuitable materials within the building footprint — proofnz|Ung of foundation and slab-on-grade subgnsdes, prior to placing fi|| or preparing for concrete placement — exposed bedrock subgnsdes prior toplacing fi|| � The Geotechnica| Engineer should be provided and review all testing and inspection reports for earthwork activities. � Subgnade conditions will be influenced by excavation methods' precipitation, stormvvater management, groundwater contro|(s)' and/or construction activities.The site soils contain substantial proportions of fine sand and/or silt that may degrade and/or become unworkable when subjected to construction traffic or other disturbance during wet conditions. The Contractor should be aware of these conditions and take precautions to minimize subgrade disturbance. � The site should be cleared and stripped of existing pavement/concrete; existing trees/vegetation; Topsoil, Roctmat, Forest Met; loamy/organic-laden Subsoil; spoils generated from other work; and any otherwise unsuitable materials. Stripping should include removal of the root structure of trees and shrubs. Organic soils may be deeper within and around the root structure. � Loose' soft' wet, and/or otherwise unsuitable soils should be over-excavated to expose suitable soils, or other remedial measures should be taken' as directed by the Gectechnice| Engineer. Over-excavations should be backfi||ed with properly placed and compacted fi||' as appropriate for the location. � Following clearing, stripping, cutting, and/orover-excavaUon' the exposed subgnade soils should be proof- rolled as recommended in the appendix Additional Eorthwork Recommendations and to the satisfaction of the Geotechnica| Engineer. Proof-rolling should not be performed if the exposed subgradesoi|s are wet, as this may result in soil pumping and instability. Therefore' the proof-rolling efforts' should be directed by the on-site Geotechnica| Engineer. � Should groundwater be encountered during foundation or utility excavations, it is expected that it will be limited in volume and/or occur as relatively slow seepage which may be controlled through standard sump and pump methods ofdevvatering. However, vve||points or other more rigorous means ofdevvatering may be necessary in the event that sumps and pumps prove unsatisfactory. 4~2 FK11Mater0a|s � To facilitate placement, stability of subgrades during construction, and long-term performance of the project, we recommend the following engineered fi|| material requirements. � JOHNTURNER, �� cumsu^nwa GEOTECHN|CAL ENGINEERING REPORT t 0,,!!1����� ��������������U������������������� ������ Below settlement Granular soils; maximum particle Structural Fill sensitive structures, size 4 inches; less than 1596 95% interior structure bacNlU passing No. 200 sieve Parking areas, drive lanes, Granular soils; maximum particle 9296below 31t from finished grade Common Fill general site fiU 96 orvvithinS1��ombackofweU' behind size retaining walls passing No. 200 sieve B596within 3 it from finished grade or beyond 3ft from back ofwall Landscape areas with no General Fill site improvements or Workable soil materials 90% slopes Non-Frost Within the frost depth Granular soils; maximum particle Susceptible below settlement size 4 inches; less than 896 95% Fill sensitive structures passing No. ZOOsieve Slab and B|endof�ranu|arsoi|send Directly be|ovvslabs and Pavement pavements crushed rock aggregate meeting 9596 Base Course local DOT requirements As Structural Fill, for wet [rushed durable rock; maximum Multiple passes of compaction Crushed Stone subgnades, and drainage particle size 96 inch; less than equipment until fully seated aggregate lO% passing No. 4sieve l. Fill materials should be free of organics, clays, frozen materials, debris, brush or tree materials, trash' and otherwise unsuitable materials, and be at workable moisture content, i.e. +/-3Y6ofoptimum. 2. Minimum compaction requirements refer to percentage of maximum dry density per ASTM D1557[. 4.3 Re-Use of Site Soils � Soils excavated during site development may be re-used as engineered fill as tabulated below. Existing Fill General Fill High fines content Glacial Till General Fill High fines content � Materials proposed for re-use should be segregated and stockpiled based on composition. Bulk samples should be submitted for laboratory testing to demonstrate conformance with the project specifications. Non'conformingmeteria|smaybeusedin |andscapedareas, providedtheycanbeadequate|ycompacted. � JOHNTURNER, �� COIN su^nwa ��EOTECHN|CAL EN(�|NEER|N�� REPORT ��Pr������ ���v����� �����������������U����� �������������� ����� 5.0 1.1 INJ Jk T 0 P�il S, JT[ believes that the structure can be supported with foundations bearing on prepared Glacial Till subgnades, provided that the geotechnical design and construction recommendations presented herein are satisfied. 0 The Topsoil and existing Fill materials are not suitable for direct support of shallow foundations or slabs— on—grade. These materials should be removed and/or replaced as described in Earthwork. 5.1 Foundation Design Recommendations 0 Design recommendations for shallow foundations are tabulated below: Bearing Stratum Glacial Till Depth to Bearing Stratum (from existing grade) 0.8 to 5feet Allowable Bearing Pressure 41000psf Design Frost Depth for Exterior Foundations 4feet Estimated Depth to Groundwater ~lGft Minimum Strip Footing Width 2 it Minimum Isolated Footing Width 3 it Estimated Maximum Total Settlement l inch Estimated Maximum Differential Settlement 1Y2 inch Total Unit Weight of Bearing Soil lZOpcf Friction Angle of Bearing Soil 32degrees Cohesion of Bearing Soil Opsf Passive Earth Pressure Coefficient 3.0 CoefficientofS|idingFriction—concretecaston 0.4 subgnsdesoi|s Based on the depth to groundwater, the potential for perched water conditions, and/or the use to the structure, we recommend foundation drains be installed.The drains should consist of minimum 4-inch diameter perforated PV['SDR35 drain pipe encased within 12 inches ofY4'inch stone and wrapped with a geotexti|e separation fabric. Foundation drains should be located at least 4 inches above the bottom of footing elevation and six inches outward from the edge offooting. 5~2 Foundation Subgrade Preparation � The foundation bearing soils should be proof compacted in the presence of the Geotechnica| Engineer to densifv near surface soils disturbed during the excavation process and to assess stability ofthe subgrade. � JOHINITURNER, �� COIN su^nwa ��EOTECHN|CAL EN(�|NEER|N�� REPORT ��Pr������ ���v����� �����������������U����� �������������� ����� 0 Due to elevated fines content, foundation subgrade soils may be easily disturbed with increased moisture content and construction traffic. The subgrade could be protected from disturbance with a minimum 6- inch thick |ayerofY4'inchminuscrushedstonefuUy'weppedina geotexU|e separation fabric. The fabric and crushed stone should be placed immediately following proof-rolling of the subgrade soils and seated with multiple passes with a plate compactor. m See the appendix Additionol Eorthwork Recommendotions for additional guidance. 5.3 Seismic Considerations Seismic Site Class 1 D Liquefaction Potential Not Susceptible l. Additional explorations, sampling, and testing would be required to potentially justify an increase in Site Class. 5.4 Slab-On-Grade 0 The Topsoil and existing Fill materials are not suitable for direct support of shallow foundations or slabs- on-grade. These materials should be removed and/or replaced as described in Earthwork. 0 Design recommendations for floor s|abs'on'gnade are tabulated below: Bearing Stratum Glacial Till � Depth to Bearing Stratum O.Oto 5feet Slab Base Course Thickness 9 inches Modulus ofSubgradeReaction 200pd l. Requires removal of up to 5 feet of existing soils � The floor slab should be isolated structurally from foundation walls and columns/piers to a||ovv for differential movement. 0 The slab-on-grade subgrade should be restored by the Contractor and evaluated by the Geotechnica| Engineer following installation ofsub's|ab utilities. 0 The requirement for a moisture/vapor barrier beneath floor slab-on-grade should be evaluated by others. � Sub-slab drainage is not required. � JOHNTURNER, �� COIN su^nwa I),411)r I�)J GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifill"I 2,1!1 0,,!!1 "I'di'D��l 1 11 .......... ... .......... Nil, 1111II,ilsl&" 111111�11 clgtist' 02111!, (D (D S E D E I ..........I [.' 111��� I Pill I D 0 11111!1�'C�...........���U S E.............S 111111II L 3,,1 5 P11111111 6.0 Cuuuum.01 S I We recommend that JTC be retained during design development to review the plans and specifications, to assess conformance with our geotechnical recommendations and during the construction phase to evaluate earthwork operations and review subgrade soils for consistency with our assumptions. We trust the contents of this 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.The contents of this report are subject to the attached Limitations. Mr JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM PAGE 10 OF 10 ),411)r I�)j GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifil"11 .2,1!1 0,,!!1 "I'di'D��l 1 1 .......... ... .......... Nil, 1111II,jjsI&" 111111�11 clgtist' 02111!, (D (D S E D E I .......... I Pill I D 0 11111!1�'C�...........���U S E.............S 111111�� L 3,,1 5 P11111111 IIIII D I X A Site Plan & Exploration Location Plan JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM APPENDIX �V V/ O \ � LEGEND U � Q � APPROXIMATE LOCATION AND DESIGNATION OF BORINGS ADVANCED ON AUGUST 7, 2024 BY SEABOARD DRILLING, LLC w ° TB-I - TB-2 U ++ O •- N CD e r E_ n _, O N z co � TB-4 TB 3 w 4 U N O N O co N L.� U � O U � O SCALE O / 0 40' 80' N DRAWING NAME: DATE: 8114124 N 1.50KING5 DESIGNATED TB-I THROUGH TB-4 WERE ADVANCED BY 5EA130ARD DRILLING,LLC OF EXPLORATION LOCATION PLAN JOB# 24-04-055 DRAWING#: CHICOPEE,MA UNDER THE DIRECTION OF JTC. DKAFT: JM PKOJECT: 3 1 5 TURNPIKE STREET DE51GN:QG 2.EXPLORATION5 WERE LOCATED IN THE FIELD USING TAPED MEASUREMENTS RELATIVE TO PROMINENT T __ EXISTING SITE FEATURES AND SHOULD BE CON51DEKED APPROXIMATE. CONSULTING NORTH ANDOVER,MA55ACHU5ETT5 REVIEW:5L 3.BA5EMAP SOURCE:'TEST PIT AND BORING LOCATIONS-LECTURE HALL-MEKKIMACK COLLEGE-3 15 CLIENT: MEKKIMACK COLLEGE KEV1510N5: TURNPIKE STREET,NORTH ANDOVER",BY VHB,DATED JULY 23,2024 NORTH ANDOVER,MAS5ACHUSETT5 ),411)r I�)j GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifil"11 .2,1!1 0,,!!1 "I'di'D��l 1 11 .......... ... .......... Nil, 1111II,jjSI&" 111111�11 clgtist' 02111!, (D (D S E D E I .......... I Pill I D 0 11111!1�'C�...........���U S E.............S 111111�� L 3,,1 5 P11111111 IIIII D I X B Exploration Logs & Key to Symbols and Descriptions Mr JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM APPENDIX PROJECT: Proposed Lecture Hall PROJECT NO.: 24-04-085 � � CLIENT: Merrimack College N TURNER 0 0 LT I�� PROJECT LOCATION: 315 Turnpike Street,North Andover,MA LOCATION: 315 Turnpike Street,North Andover,MA ELEVATION: 235.5 feet LOG OF BORING DRILLER: Seaboard Drilling,LLC LOGGED BY: Q.Guglielmo DRILLING METHOD. ATV-mounted drill rig w/HSA DATE.. 8/7/2024 No. TB=1 DEPTH TO -WATER>INITIAL: NE AFTER 24 HOURS: N/A � ^ � o � � c TEST RESULTS � °' Description CL M � � c o * Plastic Limit �� Liquid Limit � E 0 _ o � 0 00 v Water Content- • w Penetration - o J J J 235.5 10 20 30 40 50 [TOPSOIL] J J 2 •N -------------------- Brown Silty Sand(SM)with Organics; loose 7 SS01 13 ♦, -----------------------T----------------------r----------------------,-----------------------.---------------------- `0 0 [GLACIAL TILL] -`----------------------A......................A......................'.......................'...................... > Tan/gray Sandy Silt(ML),trace Gravel; loose -becomes medium dense 19 14 --=--------------------------------------------------------------------- •c 2.5 233 14 SS02 15 N , c� i E 5 230.5 11 SS03 13 16 24 O -becomes very dense,with Gravel so4 50/3" � 7.5 228 _ ------------- Y r �L - O .- }r o ...................---------------------------------------------------------------------------------------------------------------- N = 10 225.5 V -tree roots Ssos 33 50/3" Q , c - O ------------------- ------ ------ Auger Refusal Boring terminated at 11 ft. . r-------- -----------------------------------------I----------------------A---------------------; � 12.5 223 ----------------------------------------------------------------L----------------------•-----------------------•---------------------- 15 220.5 -......................Y......................:......................;.......................:...................... -----------------------------------------A----------------------I----------------------.--------------------------------------------- 17.5 218 ..................-.......................`......................�----------------------1-----------------------'---------------------- F i g u re PAGE 1 of 1 PROJECT: Proposed Lecture Hall PROJECT NO.: 24-04-085 � CLIENT: Merrimack College N TURNER 0 � 6 PROJECT LOCATION: 315 Turnpike Street,North Andover,MA LOCATION: 315 Turnpike Street,North Andover,MA ELEVATION: 236.5 feet LOG OF BORING DRILLER: Seaboard Drilling,LLC LOGGED BY: Q.Guglielmo DRILLING METHOD. ATV-mounted drill rig w/HSA DATE.. 8/7/2024 No. TB=2 DEPTH TO-WATER> INITIAL: V NE AFTER 24 HOURS: N/A � ^ � o � � c TEST RESULTS _ _ Description a m ( O o Plastic Limit �� Liquid Limit i > Z m O V o v Water Content • W Penetration - 0 236.5 10 20 30 40 50 [TOPSOIL] J J J 1 2 N Brown Silty Sand(SM)with Organics; loose J 4,14v SS01 7 J J J 10 JJJ J J J J J J 2 v 5 2 5 FILL 4 Tan Silty Sand(SM); loose SS02 7 -intermittent layers of relic topsoil N i ._ 5 231.5 10 . SS03 22 [GLACIAL TILL] 24 0 Tan/gray Sandy Silt(ML)with Gravel; loose 31 O -becomes very dense, Gravelly 26 ss04 24LL e� 4 .................... 0 7.5 229 27 'L 20 O , N ._ O ------------ :---------------------- c N C 10 -becomes dense,trace Gravel 226.5 20 SS05 33 O 33 E ------------------------------------------T----------------------r----------------------:-----------------------:---------------------- L 12.5 224 Auger Refusal Boring terminated at 13.5 ft. -------------------------------------------r----------------------r------------------------------------------------------------------- -------------------=----------------------:----------------------:----------------------:-----------------------:---------------------- 15 221 ----------------- ----- ----- .5 .....................----------------------T----------------------r----------------------:-----------------------:---------------------- ----------------------------------------------------------------------------------------------------------------------------------- 17.5 F219 F i g u re PAGE 1 of 1 PROJECT: Proposed Lecture Hall PROJECT NO.: 24-04-085 � CLIENT: Merrimack College N TURNER 0 � 6 PROJECT LOCATION: 315 Turnpike Street,North Andover,MA LOCATION: 315 Turnpike Street,North Andover,MA ELEVATION: 236.5 feet LOG OF BORING DRILLER: Seaboard Drilling,LLC LOGGED BY: Q.Guglielmo DRILLING METHOD. ATV-mounted drill rig w/HSA DATE.. 8/7/2024 No. TB=3 DEPTH TO-WATER> INITIAL: V NE AFTER 24 HOURS: N/A � ^ � o � � c TEST RESULTS _ _ Description a m ( O o Plastic Limit �� Liquid Limit i > Z m O V o v Water Content • W Penetration - 0 236.5 10 20 30 40 50 [TOPSOIL] J J J 4 ------------------ N Brown Silty Sand(SM)with Organics; medium dense J J J ssol 6 J J J 8 12 J J J 2 v [GLACIAL TILL] 11 c 2.5 234 9 ............................................................................................ SS02 Tan Sandy Silt(ML); medium dense 8 -------------------------------------------r----------------------r----------------------;-----------------------:---------------------- -orange-brown mottling i 5 ._ 231.5 11 . -trace gravel 15 c -becomes grey/tan sso3 13 r ---------------------- 15 O ------------ i t N -becomes dense 13 16 0 7.5 229 -------------------------------------------------------------- 17 'o SSO4 18 ._ O N C to -becomes very dense 226.s 5 -rock fragments SSoS 25 29 O ------------ ------------------------------------------------------- 12.5 224 Auger Refusal Boring terminated at 13.1 ft. ------------------------------------------''----------------------''......................--------------------------------------------- 15 ---------------- 221.5 -----------------------T----------------------r----------------------:-----------------------:---------------------- ----------------------------------------------------------------------------------------------------------------------------------- 219 17.5 ------------------=---------------------------------------------......................----------------------r ---------------------- Figure PAGE 1 of 1 PROJECT: Proposed Lecture Hall PROJECT NO.: 24-04-085 � CLIENT: Merrimack College N TURNER 0 � 6 PROJECT LOCATION: 315 Turnpike Street,North Andover,MA LOCATION: 315 Turnpike Street,North Andover,MA ELEVATION: 235.5 feet LOG OF BORING DRILLER: Seaboard Drilling,LLC LOGGED BY: Q.Guglielmo DRILLING METHOD. ATV-mounted drill rig w/HSA DATE.. 8/7/2024 No. TB=4 DEPTH TO-WATER> INITIAL: V 16 AFTER 24 HOURS: N/A � ^ � o � � c TEST RESULTS _ _ Description a m ( O o Plastic Limit �� Liquid Limit i > Z m O V o v Water Content • W Penetration - 0 235.5 10 20 30 40 50 [TOPSOIL] J J J 2 ssol2 ......t................................................................................................................. N Brown Silty Sand(SM)with Organics; loose J J J 5 0.9 8 .......--------------------------------------------------------------------------------------------------------------- [GLACIAL TILL] 0 -------------- -------•----------------------A----------------------A----------------------r-----------------------•---------------------- > Tan/gray Sandy Silt(ML)with Gravel; loose -becomes dense 20 .c 2.5 233 SS02 24 ............. 38 N , c� i .� 5 230.5 8 21 21 O SS03 � 23 O --------------------------------------------------------------------------------------------------------------- t N -trace Gravel 20 7.5 228 � 29 �o SSO4 32 ---------------------- o ' N •� 10 225.5 28 5 -becomes very dense 32 --------------------- 33 SSOS 31 O --------------------- ------------ T r 12.5 223 -------------------=----------------------:----------------------:----------------------:-----------------------:---------------------- ------------------------------------------''----------------------''---------------------- -----------------------'...................... 15 220.5 20 80- 30 S S 06 50/3„ -------------------- --------------------- -mottling Auger Refusal Boring terminated at 16.5 ft. -------------------------------------------------------------- F21817.5 ------------- ----------------------- Figure • -----------------•---------------------------------------------...................... PAGE 1 of 1 MAJOR DIVISIONS SYMBOLS TYPICAL NAMES JOHNTURNER CLEAN •. Well-graded gravels or gravel-sand mixtures,little or no CONSULTING W GW °'.0 ° fines N GRAVELS GRAVELS WITH KEY TO SYMBOLS AND DESCRIPTIONS J� LESS THAN 5/o GP o o ° Poorly graded gravels or gravel-sand mixtures,little or no — W FINES fines O > MORE THAN 1/2 Recessed Cover W GRAVELS WITH GM o ° Silty gravels,gravel-sand mixtures Shelby Tube Auger Cuttings :° Set in Concrete pCn OF COARSE OVER 15% *.,Top of Well, o o FRACTION No.4 3 ;.� Recessed Pipe Z SIEVE SIZE FINES GC Clayey gravels,gravel-sand-clay mixtures Standard Split 3 Split Spoon Q N ° ° ° ° Spoon Sample Sample Covered Riser ry CLEAN SANDSS °°°°°°°°° Well-graded sand or gravelly sands,little or no fines ( Z W °°°°°°°°° Capped Riser w/ n SANDS WITH LESS °°°°°°°°° Dynamic ConeTF71Locking Cover W Rock Core THAN 5% FINES Poorly graded sands or gravelly sands,little or no fines Penetrometer U)\ SP Pipe Riser 0� O MORE THAN 1/2 Vane Shear Bulk/Grab Sample Q � Concrete Seal U OF COARSE SANDS WITH S M Silty sand,sand-silt mixtures Lu > FRACTION<No.4 OVER 15% Sonic or - Sonic Sample Gravel Backfill SIEVE SIZE FINES SC Clayey sands,sand clay mixtures VlbrO-Core Sample Assorted w Inorganic silts and very fine sands,rock flour,silty or �Z Water Table Water Table Cuttings N SILTS&CLAYS M L clayey fine sands or clayey silts with slight plasticity (- at time of drilling) - U) (after 24 hours) Uj H Bentonite Slurry J> C L Inorganic clays of low to medium plasticity,gravelly clays, TYPICAL SYMBOLS LIQUID LIMIT 50%OR LESS _ _ sandy clays,silty clays, lean clays Bentonite Pellets 0 0 — Organic silts and organic silty clays of low plasticity SOIL MOISTURE MODIFIERS :•Silica sand wN OL _ Z N — — Term Description •:•blank PVC Z Inorganic silts,micaceous or diatomaceous fine sandy or -.�;{Slotted Pipe w/ c� " M H SILTS&CLAYS silty soils,elastic silts w o Dry Absence of moisture;dusty,dry to touch _:;Sand Z o Inorganic clays of high plasticity,fat clays Endcap on Pipe C H Moist Damp but no visible water Packed in Sand LIQUID LIMIT GREATER THAN 50% w Wet Visible free water l` :,Silica Sand,No > Organic clays of medium to high plasticity,organic silty O O H cla s or anic silts Pipe(End Plug) y ' g The descriptor"damp"should not be used(use"moist"). WELL HIGHLY ORGANIC SOILS PT �, ,��, �� Peat and other highly organic soils The descriptor"saturated"should not be used(use"wet"). SYMBOLS RANGE OF GRAIN SIZES RELATIVE DENSITY/CONSISTENCY PERCENT OR PORTIONS OF SOIL CLASSIFICATION U.S.Standard Grain Size Gravel,Sand,and Silt Sieve Size in Millimeters on plastic Silt(plastic)and Clay Term Description BOULDERS Above 12" Above 305 N-Value Relative Density N-Value Su Consistency Parting: >1/16 in. COBBLES 12"to 3" 305 to 76.2 0-4 Very Loose 0-2 0-250 Very Soft Seam: 0.5 in.to 1/16 in. 5-10 Loose 3-4 251 -500 Soft Layer: 12 in.to 0.5 in. GRAVEL 3"to No.4 76.2 to 4.75 11-30 Medium Dense 5-8 501 -1000 Medium Stiff Stratum: > 12 in. coarse 3"to 3/4" 76.2 to 19.1 fine 3/4"to No.4 19.1 to 4.75 31 -50 Dense 9-15 1001 -2000 Stiff Pocket: Small erratic deposit SAND No.4 to No.200 4.75 to 0.075 51 + Very Dense 16-30 2001 -4000 Very Stiff Lens: Lenticular deposit coarse No.4 to No. 10 4.75 to 2.00 31 + 4001+ Hard Occasional: One or less per foot of thickness medium No. 10 to No.40 2.00 to 0.425 fine No.40 to No.200 0.425 to 0.075 Standard Penetration Testing(SPT)N60 based on blows per 12 Frequent More than one per foot of thickness inches. Alternating seams or layers of silt and/or clay SILT&CLAY Below No.200 Below 0.075 WR=Weight of Rods;WH=Weight of Hammer Varved and sometimes f.sand REFERENCE: UNIFIED SOIL CLASSIFICATION SYSTEM - ASTM D2488-93 ),411)r I�)j GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifil"11 .2,1!1 0,,!!1 "I'di'D��l 1 11 .......... ... .......... Nil, 1111II,jjSI&" 111111�11 clgtist' 02111!, (D (D S E D E II„. P11111111('')����?I Pill I D 0 11111!1�'C�...........���U S E.............S 111111�� L 3,,1 5 P11111111 D I III C Site Photographs JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM APPENDIX T JOHNTURNER CON SU LTI PHOTO LOG John Turner Consulting, Inc. Site Location: 315 Turnpike Street, North Andover, MA Photo No. Date: Photo No. Date: 1 8/7/2024 2 8/7/2024 .. 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ME M Will Description: TB-2 (0-2 feet) Description: TB-2 (2-4 feet) [TOPSOIL] [TOPSOIL]/ [FILL] /[BURIED TOPSOIL]/ [SUBSOIL] Photo No. Date: Photo No. Date: 3 8/7/2024 4 8/7/2024 Irl I I r Y" a r r//r // � r / (I,'U ;, :1 'ry/���� '�' r,j o �➢.Nr1li/�r yl��;T l�a�rmP J/�//Y� /1;� r,; %/� i it ` %� � G /✓„ 1/ /� =/1 T�/��IJT��iJ rl'n,��, fir/`�%T Vd � °„N,�.., j ;,,,,�, ;yr,Jri'%1�%ill yr,/ � V/ 7i✓�� m�� ,, �- !� //�l f�,,. r/r<,��,, I � Cr ;/%/�%�l rc,G:; �;".Jl y//l'(r11r�� %//i9/rfrr., J T%�/✓r/'/�//l T/ J� r✓, �,,,�� ✓.% i��rr/��/r // / fib��..,lJr��f rr /�✓�l /��, „/� r,�y�,,;Ir���,wwN�Jrr`��✓r�✓��T� I�;� �f/i//1/„�,jT yr/�/L'i'�'o/% %� /P JJ r �;i/Jr err ✓ �//y�/ r gi rl/�r��/��y/i�J�1 %�/r✓%/ %/ /,yk /l�l��/ /i �i, ,�, %r,� /�i j �f/r fail%T k G. '11�i✓r,///� �' lTi/ r rJrTt j r� /rr�I�l� lJ,.J �rf/���//�fr��/i �r ��/�T it % I �l���/'�i 6✓� � '1+1��� �'`� f/ t✓lrt.7';'%rrPlr��%�ifll�rl lri�//�"�1/j%4//1���I�-p' /�� r,� ,l i'r r, %/ /ri//i�S" %/ ��/�/%! I irr�kll 1�%� ,m Description: TB-1 (2-4 feet) Description: TB-4 (7-9 feet) [GLACIAL TILL] [GLACIAL TILL] ),411)r I�)j GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifil"11 .2,1!1 0,,!!1 "I'di'D��l 1 1 .......... ... .......... Nil, "I'll 111111�11 clgtist' 02111!, (D (D S E D E II„. I Pill I D 0 11111!1C�...........���U S E.............S 111111�� L 3,,1 5 P11111111 X D Add itiona l Earthwork Recommendations Mr JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM APPENDIX ��EOTECHN|CAL EN��|NEER|N�� REPORT n�������� �*�����(")i ��������������U��������������� ��� Fill Placement and Compaction Recommendations 0 The adequacy of compaction efforts should be verified by field density testing compared to the maximum theoretical density of the material as determined byASTM DlS57' Method [. 0 AUfiUmateria|sshou|dbep|acedin |iftsnotexceedingl2inchesforheavyride'on' vibratoryroUersandO inches for hand-operated plate compactors. 0 [rushed Stone should be placed in lifts, seated with compaction equipment, and completely wrapped in geotexU|e separation fabric. 0 Where Recycled Building Materials are used as Structural Fill, placement and compaction should be observed by the Geotechnice| Engineer. 0 Fill should not be placed on soft, saturated, or frozen subgradesoi|s. Grading and Drainage 0 Grading and drainage should be provided at the site to direct stormvvater runoff away from site improvements to reduce the likelihood of water ponding near the structure. 0 Roof drains should discharge at least 5 feet from buildings or connect to the stormvveter collection system. 0 Drainage swales and/or edge drains should be added near the toe of slopes grading downward into the site to collect stormvvater runoff. The swa|es or drains should be designed to direct stormwater runoff away from site improvements. 0 Permanent fi|| or cut slopes should have a maximum slope of 2.5H:1V (horizontal to vertical) or flatter for dry conditions and 3H:1V for wet/submerged conditions. Steeper slopes may be possible with implementation ofa slope stabilization system. 0 All slopes should be protected from erosion during and after construction. Removal of Existing Improvements � Existing buildings, structures, associated foundations (including footings, foundation walls, slabs-on-grade, and/or basements), and/or utilities, should be completely removed from within proposed building areas. The resulting excavations should be replaced/backfilled with properly placed and compacted Structurol Fill. � Existing structures or subsurface utilities, including any private septic tank, leach field, and associated piping, located in areas outside of the proposed building areas may be removed or abandoned in place. Utilities abandoned in place should be plugged or capped to prevent migration of water.Tanks left in place should be filled. Structural elements to remain in place should be at least 3 feet below existing grade. Slabs left in place should be drilled or periodically broken to prevent pondingofwater. Foundation SubgnadePreparation • Footing subgrades should be level or suitably benched and free of standing water and/or debris. • Foundation subgrade soils should be protected against physical disturbance' precipitation, and/or frost throughout construction.The Contractor should be responsible for the means and methods to protect the foundation subgrede during construction. w If shallow and/or perched groundwater is encountered, it must be removed in advance of excavation and continuously maintained at least 2 feet below the bottom of excavation and subsequent construction grade until the backfiUing is complete; m Over-excavation below foundations, if required, should include the Foundotion Zone of Influence /FZ08 defined as the area extending from the edges of the footing outward and downward at a 1H:1.5V (horizontal to vertical) splay ofbearing. mr � JOHNTURNER, �� COIN su^nwa WWW.CONSULTJTC.COM APPENDIX ��EOTECHN|CAL EN��|NEER|N�� REPORT n�������� �*�����(")i ��������������U��������������� ��� Construction Considerations w The Contractor should take precautions to minimize subgrade disturbance. Such precautions may include diverting storm run-off away from construction areas' reducing construction traffic in sensitive areas, minimizing the extent of exposed subgnade if inclement weather is forecast, backfi|Ung excavations and footings as soon as practicable, grading and compacting exposed subgnsdesto promote surface water run- off andpreventponding, andmaintaining an effective dewatering program, asnecessary. � The following minimal proof-rolling efforts should beexpected. o Building pad: 8 passes with a lO'ton smooth-drum roller o Foundation Trenches: O passes with a 5-ton smooth-drum roller o Utility Trenches: 4 passes with a vibratory plate compactor o Site: O passes with a lO'ton smooth-drum roller o Proof-rolling should not be performed if the exposed subgrade soils are wet because this may result in soil pumping and instability. The proof-rolling efforts, including the number of passes and whether to use static or vibratory methods, should be directed by the Geotechnical Engineer • Safe temporary excavation and/or fill slopes are the responsibility of the Contractor. Excavations should be conducted in accordance with local,state,and federal(OSHA) requirements,at a minimum. |fenexcavation cannot be properly sloped or benched due to space limitations, adjacent structures, water seepage, or other reasons, the Contractor should install an engineered excavation support system. w |f the subgradeshould become frozen, wet, or disturbed, the affected material should be removed' or should be scarified, moisture conditioned, and recompacted. m Proper groundwater control and stormvvater management are necessary to maintain site stability. Groundwater should be removed in advance and continuously maintained at least 2 feet below the working construction grade until earthworks and/orbackfi|Ung are complete. • |f groundwater seepage and/or wet soils are observed etsubgnade level, aY4'inch minus crushed stone base may be placed over the exposed subgrade soils.The stone should be completely wrapped with a geotextile separation fabric. The fabric and stone should be immediately placed over the undisturbed subgrade and then tamped with a plate compactor until exhibiting stable conditions. w Fill should not be placed on soft, saturated, or frozen subgradesoils. Construction Dewatering 0 Any seepage of groundwater or collected precipitation should be intercepted and maintained below the excavation bottom such that construction proceeds in the dry. 0 Water collected from clewatering efforts should be screened and discharged per the project permits. Foundation8ackMU w To minimize the potential for foundation wall damage during backfill and compaction activities,foundation wall backfill should be placed in a manner that maintains a balanced fill height on both sides of the wall. Construction Monitoring and Quality Control Testing m A qualified geotechnical engineer or representative should be retained to review the site preparation and grading activities and foundation subgrade preparations, at a minimum. Similarly, quality control testing, including in-place field density and moisture tests' should be performed to confirm that the specified compaction is achieved. It is recommended that JT[ be retained to provide earthwork construction monitoring and quality control testing services. mr � JOHNITURNER, �� COIN su^nwa WWW.CONSULTJTC.COM APPENDIX ),411)r I�)j GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifil"11 .2,1!1 0,,!!1 "I'di'D��l 1 11 .......... ... .......... Nil, "I'll 111111�11 clgtist' 02111!, (D (D S E D E II„. P11111111('')����?I Pill I D 0 11111!1C�...........U S E.............S 111111�� L 3,,1 5 P11111111 D I E ASFE Geotechnical Engineering Report Information Mr JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM APPENDIX V I I I I i TI, I � I 1 Eii, I !I I � rr�rr��r ��r.,rr� ! Il UIIlow �" 1 II I1C I I I 0 Repupt 1 4 r a I I r j IIwjqj'Ij!jj%j-I MINIM, i I N F11 F"'Im, ,q u 3 e V 4 a 1 I r Ij l'! !I:M I ........... Go i r Me, ftM I'CAUServices, for µ (,le &, � I i�ml frafio�ri w W N ;o �t � YI Alt G S*wdft ftmose's, PervISIMIS.,, al ld Pr*cts proposed, 'I I w; �, ,I w , ��� h;�, composition w �me� ,�I I , f ole �I ,engineers s'� r; ti , tier f N�1 �� a� I i p f`` nee ! I � I � do o j gar� , r, theJr iw I � l civil, u� III I �uu n may,not lfiII � , c ", c ,.�"air � another ^iMl U,N u aw Because, , , u, � .I , M �m�,J I � r study. i�unique,, , ry, always", I . .,� � „, , ��I y : :. �� " ��I,I�: ��'" ��I . Ir f �project iL � a , �� m ones-and � j;assess w fIh i, " rvi . , riI i l � r , e o , u c , , d L N .. � ,M mr ut,:,.ti' is ei ,'. 'I °.�'�,,% � - ;; 1. , - ! l,.. .. V„ „„- ",:�. , ane,, ,fill%,,...r V,. 'I ., ,. '.... should I, ( , r � � � I ,� � �I hl w .,. � ,. ,. "w ",' :". -I ,, ,,.) : I ;V.' '..; ,.,(..,, 1. �whn '" I "'.. 'I I,;. wwi I. ,.., , ,. �. :. ,, 1;.. of +, I ,Ir ;. I r first c ��r "� r i + � � � �� R. � � � � of � � I III�°I � �1 N , se or proj Subsurbee Cbmp CandUM Cm I Read IN FW`I ROOM A gleatechnical engineret',ingw jo,,ri cortdificnstfialexistejal � I r.I !s problems, p l ; W Ua r ... c .uN I D b ,,,1. 1 ell, N W onV I I 4 r�l c C J e l m th,. study d; was, H',r,, Ie d m. ..o o v r . �a .. I V I� , - 'n i, e", I, report. `i4 not, eY It lL o not ML . , :n M wi,I� d ! s adequacy i have been affected » p "he pass, ,: _" ", � ury r! v i W � , v w Do , read '; elementsted ,, ' w uo w i. a 6".lu i.;t q, � IIo Inewt 1� i i`s„,I b; s, N I� i ,eN l q rs o i , i �I uai-,91 GeataCbRICM I I Based r,,,I ,r- �� � ,y+KKi I': I...� r ".,..,�,ywu tyw I �u I�,�'��r, I�Up,ww .u�+ „'� ��r a �a IM"1w'<':..,a ",� �;.I I I � w I�.+V I I,, II I I ! u I i + I III, UnIque Set, '�.. r,.. Oct. ;; - � .. ,AI -� j""VY'wvw� «yv�l��pYl"IIYIIryI� IfI� pgil+'��':pw I ,IY��wIII',WIIfr w;p�;u� w" lu �r III�I�I^+,ml��rl,�,.' II�gI w ,; Itesting u�y�, V, Bglp� 6fW��r V. of S I , Factors, - U ,."''��Iw i.. It VA'ITV i I Iq"s s',,l V9�N"91:'. I���w� Iv W N1M �'R. t wgyu�,IW�N IWI�wwcer'.,�"IIN ,Il, & I �gll ll h 9 m I 1 ...� .'.�I,.. :. , ",. I , 4`�� I I is +�., I I I., I•,; ,:i. problems, " ,�:.J I.. midst J �� unique,„ jec � ��� I ����� �.m�x� l en establwhishrig the scope, a sDill T ical fa m include:the; *;d ,`l r; :�'�V; o ,rkww,"rr N,pI';. °w':.€ M.,I;' 1. V I.d lida',..� � �p�: II'aI�I'I ��+.�..', � �" dl rPromfessio i. �1 �',,, bJ cti - sk i - "+' binoesthe °ever 4 „ .,. H,,fI`,rftvs r i o h structure involved,, it s� � � I fi Iw fi l�I,,� i N° c ��I � fUP1,111"dow d e, . u,. a r, , s I,-wNI and I . p, planned, r u. .I,'.. 4I; ,, :improvements, , V , r Ix 1� ,a am i;dgN t i a .." I I , ��� ,i i s ii I. ,.a;t i, s f + � I r smcb as access, a s I„ I rkiilrig lolss, � i i r U = utiI i r :sm. Ifq �l ft�� subsurface , m I �� h; II !I d ±�� I fi ,� � � , i rv, r ,e w:,��,�. ...�. a ,q. _. m., 'M .: ;.; e: n�. " , :riv,... i r u : I i, ,, I". .. .. a .. v , P< � ,., '�. gud. ,.. �..II '". a ,. �.,.. �..". ,.I. '. I .fir. ,.. 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I I � I ire l „ ° dope � � ,,to vi �� ho i' h completed I I I I s fchanges, �v� „ � �I + most � � ing frisks,a p ! ri i Iu I II , ; e condifti a ns,. a erode;t cl;is I l i a l f n ii,"I'Ji g geon"le, hnicali! engil"Ineering report','H,,mlude those Ifiat aft`ect. A RepoKs RammeNsfien Are ftt FIM u ! I " I 1,' I I I r I rw ry .4.'. ,,��"��;, I,��" , y�.��t-�pp��,ry�A�,. ... ,o � � �r."'�yk� ,. I I...� "�! I''., I'�.. � r. ;,��..U. �IIIry� "��,pq�I��I,. ;II ; 0 Ii"....I 1IµVI� ,...I�i �""-�: ;� I I� V I`.yIyII'� �,� I�L.. your W���.^ ' �, � I� .�!Wy�� �Iwinf' I�W�,"uw'�Uw� �P..WhuN,�, Mr^M�w' ml�,„�. k�i I:IW a� w�WMr� .,.� MI�,.. � � ,.1� �� IW d II�on�. "�P'� 'r�9�^' �'p 1" �" � '' � w ^� ,.. IRII pE 0 RR�`�� uuP^P J :�, ,,. h.":, , 9 ....,. ,.z'Y '.. IX ,� W I. od'� gyp., Those, . ," ,{,l '�I MYW +'.... yy I.. �., ..' IM,. I rig � 1 :r�jly, I Ivry.office, yppmlywl III y1II ng or jll�wpl�{�II r��,'q@��� I i i 11,.I i,u�Iwlwlw". qj��I""Il II�'I�I„{I I f I Il�."i oft, n��' , j���$`�p,,i �I,V,� , ��� ,,�,I %; r I� .. I� ,. �I ", ,W'Ip U"IV�� .. �,2' „ 'R!W ^ ��,�. �fr��w�IR'!C ^M �'W!� � 11 ;i1i ���MI) ,� �'�I '...��W W� ��TXRw^" ¢M'I � '....�. IY�'41"il�w u��dµµ�V ,.�'.��IN IIV �I ; r erale� ware, „ ,h,N Will epr',(w, develop Ih,,Ti pr1incipally°from Judgmentand opinion, I I ! un I r w ..... , e h n Prrvrvvvv ar,r,rm »s».nrv.,, m,»,:;W,rr,, ,........... �� �."��i'I .. uu rvrrrvp arara ".f9.«✓Nwuwwaw.ru[r'. rmrr..ffff5"�dirw" ,rmrN,..,.., ..., �.,�, iiiiiiiinn v®immiiiiiiimua® ,niuia �✓iiiiiii�iiiiiiiii�.n..niiiiiivnr�i.�rim�nimniiiiv.. .......... slubsti0ace,condihorlts reveacled 6 ir'nig,construic 11ii,mv, '"he, rients,claiffis,,,and displute To help risk ftave led to disappointrT ie eer wito,develo,pedylow report mi noolt awvresp, ifity lor of such lat AcaMes,geotechr]ic2l in g 1 neers,comnl�wn ly nc I We a vat ieet'Y 01" om s,lit#W aqv"neer, not perform mel"mes la d 1'm tat ons"' 6( Or therepoff,"s ret fll,d explianatory provisions in'their riep oqs.So I bele I I i 1i c �s obsef vaW tt� "jisions"rid"cate,where geotecbain�'cal leng'neiers'respons'- on,tru, On", rony of ese prov" I 1 11 11 �h P e 11, IBS bififies begin and enud,to 6 otfihe-rs, reciotiqlInizz, their,D�wn res-palns'bli IAJ SUbjeet, t rissks. Rea'd' thilieseparo 7' close�y Ask quest ons. Yo u r lg,�Bl Dtech n i ca I A 1GWt8C1WC31 Engineerft R"M a and V S1010 erigl nf,*,r sh,`,hou�d respiDf,,.1,d fu I ly and frdnktyl Other de ilgiri temn t FT'ieirrrlt ,rS.`rrii�s'ntef,,,P,re,,I,,,,at'o�n of qe,,�,00te- e�ngirw,, :r4lig repoas has ressultM in CDS'tly probjems,l Lower t'hat rtsk,I;y having, iur,gff.)�-, Gamvir mmen�,Itsl C wc�erns Ape Not Covered ;h 10'ro,(I_, ,al eng'it a,),r con'ter with,appropriate metniiibeerrs lot the,desiqri tean after e equipi rrent, tec[miques%,and,pelrsorinci Usedto perform a,geven �a te ,l f*u ,n,,' y r-si 1 it! j ,,',g,n a,,,n,tl�yfro�m,th�,o,�s,eu��sedto�p,ert,ormii,,,g c �fflca I I t- mental 5W id, �d iff submiffring therepM,,-,,AJ,1,-s,,,,c,reeitaJ,,inyaur geotechnical enginev''torev low Ped" "te I eng ,an stuidly.For-that reas,,,,o,,n,,,a,geo achnica jlneertng repadr does, niot usually 1 c nertellemenlls of I hie,"desv gintcami"s plans,and s� ificat ons.Contractor's ,-t A I rell al,e an, y geoe nv,l r,an,me, nta I f�i n 6 n gs,,cl o n c us, o ns,o r rew,n,,,men dat"i o n s, ica; o ike iter,ilnig e t I nstru d o 'counit rounid storage tainilks,';ofi I'mving YDUT geotech n Cali lriieer padi"ici p,ate in p reb id andl,",prF,,,x,"n cfl e.gi,,about,ttic 1 1,holiy �f er, uind �u c.onte,rences,,,and lby,providing co'nstru,,(ctioin observaticn,,, reg,lated canta il narits,. Un,antic) anik, nmenta1parabl/ems,hate-Ied to,ntitwrot f "Ife 'I ,,d y,u r awin,ge e alih lfyotl have not ylelr,obta ric, ' o , o j,�a[cijoinsdIanit foir d' k rTrian- DO iftlt RO&Mthe Enwin,00,101 LOP virlonmeintal lnfonation,,,ask, mir,geotechinic S Gootechn"Ica I engi n"teir's P repare f1i"ria I bod ng and test"ng I o.gss b,a 'I sed upon ageme t guidance. 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A,SF111 11 fS T PTO Fit 11 01 V I A It I 8811 v"lle G"1066,Silver Spring Ni'f) 2019,10 , ,�3,01,,)(5,80-2,017 1"elephone,301/55,655-2733 R,ii,;r,,,:s, lrri��4 P,�, e-malfl,, infc),(, I:e mg wwas"fe,mig Cop"Y11"g,111 21004 byASFE,tric',By,1 0 c mpt wit)"i ASFrl� P kallfian 110,prod"octl Of'Copying of, lis dolcuroAant",�"n Whok 0,(40,PAPI,O�y Mly"M',08,175)WfM1S`M1Vv(,'iS 516 pfrahibided,,v la, Specifir W"'Offen pverm4stn Excerpow,quab"na,alvatherwo,"sw extrer,,ting, wordipg from this docflumanif is permifted vmtk"Wth"l'U'le sxptesls cwfASff.,,arid air,)Of for pu,rpons ort lschafsr�yresswvch lor ti®r A review 0*m,embes Of ASt '004y useffi3O docum,ant as a coorplemen,I to,or as an, Oki M—Sm ora owtachvito evoinvering ropoti,Any ather 'ivd , t fift"",,,inty, val,Or atherl antilly halt,�iso uses-MM,documelat Withoutbeiry an ASZFEmember W—vi'd,be,copurlitinvil negaivent ar intenr0i(haidident) I IGER05,085-0M,RP ),411)r I�)j GEOTECHNICAL ENGINEERING REPORT ro 11'e"'Ifil"11 .2,1!1 0,,!!1 "I'di'D��l 1 11 .......... ... .......... Nil, "I'll 111111�11 clgtist' 02111!, (D (D S E D E II„. I Pill I D 0 11111!1C�...........U S E.............S 111111�� L 3,,1 5 P11111111 D I Limitations Mr JOHNTURNER, C 01 N S U L T I N G WWW.CONSULTJTC.COM APPENDIX ��EOTECHN|CAL EN(�|NEER|N�� REPORT ��Pr������ ���v����� �����������������U����� �������������� ����� Explorations l. The analyses and recommendations presented in this report are based in part upon the data obtained from widely-spaced subsurface explorations. Subsurface conditions between exploration locations may vary from those encountered et the exploration locations. The nature and extent of variations between explorations may not become evident until construction. If variations appear, it will be necessary to re-evaluate the recommendations of this report. 2. The generalized soil profile described in the text is intended to portray the typical subsurface conditions at the site. The boundaries between strata are approximate and have been developed by interpretation of widely-spaced explorations and samples; actual strata transitions may be different at each location and across the site. For specific information, refer tothe individual exploration logs. 3. Water level readings have been made in the explorations under conditions stated on the logs. This data has been reviewed and interpretations have been made in the text of this report. However, fluctuations in the level of the groundwater may occur due to variations in rainfall,temperature, and other factors differing from the conditions at the time the measurements were made. Review l. We recommended that John Turner Consulting, Inc. (JT[) be retained to review the design drawings and specifications to evaluate the appropriate implementation of our geotechnical engineering recommendations. 2. 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 should not be considered valid unless the changes are reviewed, and the conclusions of the report modified or verified in writing by JTC Construction 1. We recommended that JTC be retained during construction to observe compliance with the design concepts, specifications, and recommendations and to recommend changes in the event that subsurface conditions differ from those anticipated prior to the start ofconstruction. 2. Site safety, excavation support, and clewatering requirements are the responsibility of others. Use of R 1. This report has been prepared by JTC for the exclusive use of the addressee for the specific project discussed. All considerations are based on the available information, in accordance with generally accepted geotechnical engineering practices. No other warranty, expressed or implied, ismade. 2. This report was completed for preliminary design purposes and may be limited in scope. The report includes our geotechnical.recommenclations for the project.The final drawings and specifications may or may not have followed our recommendations.The report should be considered a reference document, not a specification. 3. The scope of services for this report did not include any environmental or biological(e.g., mold,fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials, or conditions. If the owner is concerned about the potential for such conditions, other studies should be undertaken. Mr � JOHINITURNER, cumsu^r/wa �~ vvWW.comsuooTc.coM | Appsmo/x \\vhb\gb1\pioj\Wat-LD\1162537 Merti—k Lecture HaII\cad\Id\Eng\Stonnwater\Test Plts\LM TP Plan.9 TURNPIKE STREET/ROUTE 114 TURNPIKE STREET/ROUTE 114 9 ... ............ v� 10 e u .0 AHERNE ROAD 011 Jf 23549 I \ EN _. 5 ._ t B-2 V� �... I PROPOSED LECTURE MALL �— b, FFE=237.0 EN F TB-4 23635 � \� 1- 23547 EN � T P Al 01 All a \ M1 4 e t '�B— e AN 5 c PROPOSED BORING A1 PROPOSED TEST PIT IlbTest Pit and Boring Locations Figure 1 - Lecture Hall Q0 10 20 40 Feet Merrimack College 9/6/2024 315 Turnpike Street,North Andover TEST PIT LOG Page I of 3 V1,1b DATE: 2024-08-09,9:00am LOCATION ID: TP-1 CLIENT: Merrimack College PROJECT: Lecture Hall LOCATION: 315 Turnpike St,North Andover,MA 01845(Main Campus) GRADE ELEV: 234.8 see attached figure MONITORING WELL ELEV: N/A North Andover,MA TEST PIT BOTTOM ELEV: 226.8 VHB REP: Nathan Poretta,SE,PE WEATHER: 70°F,Foggy CONTRACTOR: Quirk EQUIPMENT CAT 304 ESHGW: n/a OBSERVED WATER TABLE: n/a A 12 F Loamy Sand,Gravelly Dk.Br. Loamy Sand New A Layer 19 24 36 48 C 60 F Loamy Sand,Gravelly and Cobbly Lt.Br. Loamy Sand 72 84 96 96 108 120 Legend n/a F=Fine M=Medium C=Coarse F/M=Fine to Medium F/C=Fine to Coarse V.=Very Lt.=Light Dk.=Dark Observed Gr.=Grey Br.=Brown Yel.=Yellow Org.=Orange Groundwater U.S.C.Code=Unified Soil Classification TEST PIT LOG 00 r Page 2of3 ii11 ,Vilb DATE: 2024-08-09,10:15am LOCATION ID: TP-2 CLIENT: Merrimack College PROJECT: Lecture Hall LOCATION: 315 Turnpike St,North Andover,MA 01845(Main Campus) GRADE ELEV: 236.1 see attached figure MONITORING WELL ELEV: N/A North Andover,MA TEST PIT BOTTOM ELEV: 228.6 VHB REP: Nathan Poretta,SE,PE WEATHER: 75°F,Cloudy CONTRACTOR: Quirk EQUIPMENT CAT 304 ESHGW: n/a OBSERVED WATER TABLE: n/a A 12 F Loamy Sand,Gravelly Dk.Br. Loamy Sand New A Layer 18 24 36 48 C 60 F Loamy Sand,Gravelly and Cobbly Lt.Br. Loamy Sand 72 84 90 96 108 120 Legend n/a F=Fine M=Medium C=Coarse F/M=Fine to Medium F/C=Fine to Coarse V.=Very Lt.=Light Dk.=Dark Observed Gr.=Grey Br.=Brown Yel.=Yellow Org.=Orange Groundwater U.S.C.Code=Unified Soil Classification e \: 101 Walnut Street Vhb Watertown,MA 02472 P 617.924.1770 Frimpter Method - High Groundwater Levels in Massachusetts Project The Lecture Hall at Merrimack College Client Merrimack College Project# 11625.37 Location 315 Turnpike Street,North Andover,MA 01845 Calculated by NAP Date 9/4/2024 Checked by Date USGS Well Location: Topsfield,MA USGS Well ID: MA-TQU 1 Land Surface Elevation: 131.6 Well Depth: 22.5 Topographic Setting: Till Lithology: Till Data: 2/8/1936 Date: 8/7/2024 IN Sh Estimated depth to probable high groundwater at the site (see below) Sc Measured depth to water at the site 13.67 OWc Measured depth to water level in observation well used to correlate with the water levels at the site 5.22 OWmax Depth to recorded maximum water level at the observation well which is used to correlate with the water levels at the site. 95th% 7 Sr Range of water level where the site is located 11.74 OWr Recorded upper limit of annual range of water level at the observation well used to correlate with the water levels at the site. Boring Ground (Sc)Depth of Water from Water Groundwater Depth to Probable Probable High Elevation Ground Surface*(ft) Elevation Correction Factor(ft) High Groundwater(ft) Groundwater Elevation T134 235.5 16 219.5 5.04 10.96 224.5 9/11/202411:27 AM 11625.39_Frimpter_CalculationFrimpter Adjustment(Topsfi TB4 brim heir I[:,e rt J d ��� uuuuuol uuuuuumu�d a IVuum uuuuuuum I I Vd���u���IVuu uuuuuuuuu II I�����Ieq m mi �IIIIIIu� uuuuuuml I ul oouum loll m C-3 Appendix C:Standard 3 Computations and Supporting Documentation lib Recharge Calculations Project Lecture Hall at Merrimack College Project# 11625.37 North Andover,MA Calculated by RD Date 9/10/2024 Checked by REQUIRED RECHARGE VOLUME Hydrologic Area Inches of Runoff Volume Soil Group(HSG) (ft`) (in) (ft) A 0.60 0 B 0 0.35 0 C 21,350 0.25 445 D 0 0.10 0 TOTAL 445 CAPTURE AREA ADJUSTMENT Required Recharge Volume(ft) 445 Total Site Net Impervious Area (ft) 21,350 Total Site Impervious Area Draining to Recharge Facilities(ft) 18,650 Capture Area Adjustment Factor 1.14 Adjusted Required Recharge Volume(ft) 509 PROVIDED RECHARGE VOLUME SYSTEM A: Stormtrap SingleTrap(5.0'H) Volumes provided below the lowest outlet at elevation: 230.0 Provided Volume: Bottom Area Volume (ft) (ft) 1,097 2,943 Drawdown: (Vlnfiltration/ABottom)/Rawl's Rate Rawls Recharge Rate: 0.52 (in/hr) Drawdown Time: 61.93 (hours) RECHARGE VOLUME SUMMARY Required Recharge Volume: 509 (ft3) Total Recharge Volume Provided: 2,943 (ft3) \\vhb\gbl\prof\Wat-LD\11625.37 Merrimack Lecture Hall\ssheets\Stormwater\11625.37-Recharge&Drawdown Calculations 1 of 1 .brim fir I[:,e rt 111 111 111) uuuuu°uuu uumm Sill"Itaged Sllllllta��rageA��reas C-4 Appendix C:Standard 3 Computations and Supporting Documentation 11625.37 - PR Type /// 24-hr 100-Year Rainfall=7.95" Prepared by VH6, Inc Printed 9/5/2024 HydroCADO 10.20-5a s/n 01038 ©2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond P1: StormTrap ST2 Single 5-0 Elevation Surface Storage Elevation Surface Storage (feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet) 226.50 11097 0 231.70 1,097 4,490 226.60 13097 44 231.80 1,097 4581 226.70 13097 88 231.90 1,097 4,672 226.80 13097 132 232.00 11097 4,763 226.90 13097 176 232.10 1,097 43770 227.00 13097 219 232.20 1,097 43776 227.10 1,097 309 232.30 1,097 4,783 227.20 1,097 399 232.40 1,097 4,790 227.30 1,097 489 232.50 1,097 4,796 227.40 1,097 578 232.60 1,097 4,798 227.50 1,097 668 232.70 1,097 4,799 227.60 13097 759 232.80 1,097 4,800 227.70 13097 850 232.90 1,097 4,801 227.80 13097 941 233.00 11097 4,803 227.90 13097 1,032 233.10 11097 43804 228.00 13097 1,123 233.20 1,097 43805 228.10 1,097 1,214 233.30 1,097 41806 228.20 1,097 1,305 233.40 1,097 4,808 228.30 1,097 1,396 233.50 1,097 4,809 228.40 1,097 1,487 233.60 1,097 4,810 228.50 1,097 1578 233.70 1,097 4,811 228.60 13097 1,669 233.80 1,097 4,813 228.70 13097 1,760 233.90 1,097 4,814 228.80 13097 1,851 234.00 1,097 4,815 228.90 13097 1,942 234.10 11097 41816 229.00 13097 2,033 234.20 1,097 43818 229.10 13097 2,124 234.30 1,097 43819 229.20 1,097 2,215 234.40 1,097 4,820 229.30 1,097 2,306 234.50 1,097 49821 229.40 1,097 2,397 229.50 1,097 2,488 229.60 1,097 2579 229.70 13097 2,670 229.80 13097 2,761 230.00 13097 2,943 230.20 1,097 3,125 230.30 1,097 3,216 230.40 1,097 3,307 230.50 1,097 3,398 230.60 1,097 3,489 230.70 1,097 3580 230.80 13097 3,671 230.90 13097 3,762 231.00 13097 3,853 231.10 13097 3,944 231.20 13097 4,035 231.30 1,097 4,126 231.40 1,097 4,217 231.50 1,097 4,308 231.60 1,097 4,399 Stormwater Report Appendix D*. Standard 4 Computations and Supporting Information > Water Quality Volume Calculations > TSS Removal Worksheets > Phosphorus Removal Worksheets D-1 Appendix D:Standard 4 Computations and Supporting Information .brim fir I[:,e rt Wallllllte��r V&���u��rne D-2 Appendix D:Standard 4 Computations and Supporting Information 00 uW 11b Water Quality Volume Calculations Project Lecture Hall at Merrimack College Project# 11625.37 North Andover, MA Calculated by RD Date 10/28/2024 Checked by Date Infiltration Systems Runoff from subcatchment area PR-1 Water Quality Storm Runoff Depth (in) 1.0 Total Impervious Area (ft2) 21,350 BASIN WQV: Required Volume: Runoff Depth to be Treated Required Volume (in) (ft3) 1.0 1,779 Provided Volume: Total Storage Capacity (f t3) System A- StormTrap SingleTrap (5.0'H) 21943 Total 2,943 \\vhb\gbl\prof\Wat-LD\11625.37 Merrimack Lecture Hal l\ssheets\Stormwater\11625.37-Water Quality Volume Calculations 1 of 1 .brim fir I[:,e rt mu ova I iilllu Pu uuuumuum uuuum�uuu uuum IIIIVVVII Vu !' D-3 Appendix D:Standard 4 Computations and Supporting Information 1100 Vilb Corner Development at VH B, Inc.. e 101 Walnut Street Project Name: Merrimack College Sheet: 1 of 1 Post Office Box 9151 Project Number: 11625.37 Date: eP' Watertown,MA 02471 Location: North Andover, MA Computed by: KU P 617.924.1770 Discharge Point: DP-1A-1A Checked by: Drainage Area(s): PR-1 A B C D E Amount Removed, Remaining Lad, BMP TSS Removal Rate Starting TSS Lad (C*,D) P-E) WQV 50% 1.00 0.50 0.50 Subsurface Infiltration 80% 0.50 0.40 0.10 Structure 0% 0.10 0.00 0.10 0% 0.10 0.00 0.10 0% 0.10 0.00 0.10 *BMP and TSS Removal Rate Values from the MassDEP Stormwater Handbook Vol. 1. Treatment Train **Equals remaining load from previous BMP(E) 90% TSS Removal = \\vhb\gbl\prof\Wat-LD\11625.37 Merrimack Lecture Hall\ssheets\Stormwater\11625.37-TSS Removal Calculations Cl%doNl�fTECH"' ENGINEERED SOLUTIONS CDS ESTIMATED NET ANNUAL SOLIDS LOAD REDUCTION BASED ON THE RATIONAL RAINFALL METHOD MERRIMACK COLLEGE LECTURE HALL NORTH ANDOVER, MA Area 0.43 ac Unit Site Designation WQU Weighted C 0.9 Rainfall Station# 67 tc 6 rniiin CDS Model 1515-3 CDS Treatment Capacity 1.0 cfs Rainfall Percent Rainfall Cumulative Total Flowrate Treated Flowrate Incremental Intensity Volume' Rainfall Volume Removal in/hr °(/°) 0.08 41.0% 41.0% 0.03 1 0.03 39.0 0.16 23.9% 64.9% 0.06 0.06 22.2 0.24 11.5% 76.5% 0.09 0.09 10.5 0.32 7.4% 83.9% 0.12 0.12 6.6 0.40 4.4% 88.3% 0.15 0.15 3.9 0.48 2.9% 91.2% 0.19 0.19 2.4 0.56 1.8% 93.0% 0.22 0.22 1.5 0.64 1.2% 94.2% 0.25 0.25 0.9 0.72 1.6% 95.8% 0.28 0.28 1.2 0.80 0.8% 96.6% 0.31 0.31 0.6 1.00 0.6% 97.1% 0.39 0.39 0.4 1.40 1.4% 98.6% 0.54 0.54 0.9 1.80 0.9% 99.5% 0.70 0.70 0.5 2.20 0.5% 100.0% 0.85 0.85 0.2 0.00 0.0% 100.0% 0.00 0.00 0.0 0.00 0.0% 100.0% 0.00 0.00 0.0 0.00 0.0% 100.0% 0.00 0.00 0.0 0.00 0.0% 100.0% 0.00 0.00 0.0 0.00 0.0% 100.0% 0.00 0.00 0.0 0.00 0.0% 100.0% 0.00 0.00 0.0 0.00 0.0% 100.0% 0.00 0.00 0.0 90.8 Removal Efficiency Adjustment2 = 0.0% Predicted %Annual Rainfall Treated = 100.0% Predicted Net Annual Load Removal Efficiency= 90.8% 1 - Based on 7 years of data from NCDC station #3276, Groveland, Essex County, MA 2- Reduction due to use of 60-minute data for a site that has a time of concentration less than 30-minutes. .brim fir I[:,e rt I IIII Ileum uuova Ijj�� llIIIIIIVi1^ ul� D-4 Appendix D:Standard 4 Computations and Supporting Information Site Summary Project Lecture Hall Project at Merrimack College Project# 11625.37 Calculated by AP Date 9/4/2024 Checked by DT Date Impervious Area to Average Area Area to Treatment P Load Removed Treatment Category Category(ac) (Ib/yr)Treatment Category P Load of Impervious Area (Ib/yr) Weighted P Reduction (ac) (% ) Structural BMPs 0.6 0.4 1.0 1.0 95% Untreated 0.4 0.1 0.1 0 0% TOTAL 1 1.0 1 0.5 1 1.1 1 1.0 1 84% Structural BMP Calculations O` V' hb Project Lecture Hall Project at Merrimack College Project# 11625.37 Calculated by AP Date 9/10/2024 Checked by DT Date Water Quality Results User Inputs Phosphorus BMP Design Impervious Pervious Catchment Runoff Depth Impervious P Impervious P Pervious P Pervious P Total P Load P Load P Removal BMP ID BMP Type BMP Soil Type Storage Catchment Catchment Catchment Primary Land Use Primary from Impervious EPA Water Quality Curve Loading Rate Load to BMP Loading Rate Load to BMP to BMP Credit Reduction (�) Volume(ft) Area(ft) Area(ft) HSG Area(in) (lb/ac/yr) (Ib/yr) (lb/ac/yr) (Ib/yr) (Ib/yr) (Ib/yr) System A Subsurface Infiltration System Loam(0.52 in/hr) 2,943 18,650 5,600 Multi-Family and High Density Residenti HSG C 1.9 Infiltration Trench 2.3 1.0 0.2 0.0 1.0 99% 1.0 Untreated Area Calculations %rf-hb- Project Lecture Hall Project at Merrimack College Project# 11625.37 Calculated by AP Date 9/10/2024 Checked by DT Date User Inputs Load Calculations z 2 Impervious TP Loading P Load of Impervious Area Untreated Area ID Impervious Area(ft) Pervious Area(ft) Land Use Rate(Ib/ac/yr) (Ib/yr) PR-2 2,700 15,600 Multi-Family and High Density Residential 2.3 0.1 \\vhb\gbl\prof\Wat-LD\11625.37 Merrimack Lecture Hall\ssheets\Stormwater\11625.37-BMP WQ Credit Calculator Appendix E: Standard 8 Supporting Information List of recommended Construction Period BMPs Recommended construction period maintenance checklist E-1 Appendix E: Standard 8 Supporting Information .brim heir I[:,e rt s It 0 uumm C uuuu uuum uuummllll u I I I uuum uuuuuumuic o���,,"n e��n d uuuuuuuuu i u c o uuuuuuuuu muuuuu I m E-2 Appendix E: Standard 8 Supporting Information J'�vhb Recommended Construction Period Pollution Prevention and Erosion and Sedimentation Controls 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. Compost-Filled Siltsock Barriers Compost-Filled Siltsock barriers will be placed to trap sediment transported by runoff before it reaches the drainage system or leaves the construction site.Where necessary or where shown on the plans,two rows of siltsocks may be used to provide enhanced protection for erosion-prone areas. Silt Fencing In areas where high runoff velocities or high sediment loads are expected, siltsock or straw 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 siltsock barrier will be replaced as determined by periodic field inspections. Catch Basin Protection Newly constructed and existing catch basins will be protected with straw bale barriers (where appropriate) or silt sacks throughout construction. 000 Construction Exits Temporary crushed-stone construction exits 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. Diversion Channels Diversion channels will be used to collect runoff from construction areas and discharge to either sedimentation basins or protected catch basin inlets. Temporary Sediment Basins 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. Vegetative Slope Stabilization 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. Erosion control blankets shall be used in all areas where slopes exceed 3:1. Street Sweeping Street sweeping of site and adjacent roadways will be completed throughout construction as necessary. I� Maintenance > 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 in accordance with the compliance path chosen during the NPDES CGP Notice of Intent (NOI) process. Records of the inspections will be prepared and maintained on-site by the contractor. > Sediment shall be removed from behind barriers if buildup exceeds half the bale height. > Damaged or deteriorated items will be repaired immediately after identification. > The underside of straw bales should be kept in close contact with the earth and reset as necessary. > 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. .brim heir I[:,e rt uuuu uml uum°11luuuu�I � I I uuu oll umlu� uumVl IIIIIVuumuu� umlu� a uuuuuuuuu I IlVmuu � � uuu uuum nm E-3 Appendix E: Standard 8 Supporting Information Canstructil ° r IIIII °°°° Maildn'tenance/ IIIII Chedk���ilst The Lecture Hall at Merrimack College- 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: Erosion Weekly and Sediment build up, broken Control after any bales or stakes Barrier/ rainfall Silt Fencing Construction Weekly and Filled voids,runoff/sediments Exits after any into street 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: Stormwater Report Appendix F: Standard 10 Computations and Supporting Information > Illicit Discharge Statement F-1 Appendix F: Standard 10 Computations and 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 site was previously undeveloped with no known illicit connections associated with the sanitary sewer or storm drainage infrastructure. 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. -� °- Fr. Bryan Kerns VP & COS [.3ry rn Kerns(Sq',):.1.:1.,2024:1 9:1. I[:::::II: F) Signature Printed Name 315 Turnpike Street North Andover,MA01845 Address Telephone Number Sep 11, 2024 Date \\vhb.com\gbl\proj\Wat-LD\11625.37 Merrimack Lecture Hall\Reports\Stormwater\Appendices\Appendi x F-Standard 10 Computations and Supporting Information\F1-Illicit Discharge Statement.doc t iirii t it I[: 1 ,irt F-2 Appendix F: Standard 10 Computations and Supporting Information .brim heir I[:,e rt Appendix G*.Approved Stormwater Management Plan Documents Merrimack College Master Drainage Study and Hydrologic Analysis & Original Order of Conditions (DEP File No. 090-0750) Amended Order of Conditions (DEP File No. 090-0750 51"Amendment) for Campus Parking Improvements (Latest Issuance) Peak Flow Summary by Project per Campus Stormwater Management Plan G-1 Appendix G:Approved Stormwater Management Plan Documents '.brim heir I[:,e rt u d y ���i d uuuum I I m luul �Cd��������ege ��\Aaslllte��r uuuuu luuuumn III I. IIIIIIIU uuuuuuuuuuum luumul uuu A���iia��� sll��s IIIVu� I illlullunln im G��r-de���10-- uuu uuuuI ul II Y ��� ' II IIIIIIIII uuuulllll IIIIIIII uuuuuuum uuuumuuuul m 9 0 u 0 IIII u " 5 G-2 Appendix G:Approved Stormwater Management Plan Documents A'PR 2 CON S - ernmack College 5 Andover and North Andover, Massachusetts ' 3j .S Q I! MASTER R► GE STUDY AND • T ,}y HYDROLOGIC ANALYSIS 71897,01. 1 S Turnpike Street = North Andover,Massachusetts Date; Aprill 26, 1999 , i Applicant: Merri'mack College 315 Turnpike Street North Andover, MA 01845 Application Propor . Sasaki Associates, Inc. 64 Pleasant Street Watertown, MA 02172 a •" OVERVIEW Merrimack College is located on 22 ±acres in both Andover and NorthaAndover, Massachusetts. The school is bounded bar Route 114 to the east, Elm Street to the north and residential development to the west and.south. Fart of the campus is widlin the watershed of Berry Brook, a tributary to the S aws een River. The Bcrty Brook'watershed contains approximately 479 ' total acres. In 1996 and 1997, the Town of Andover and Merrimack College retained Charles Fuller to study the Berry rook watershed, i dentify p ro blem drainage areas, and make recommendations. Three sites were identified a creating flow resttictions during high flow storm events: the Elm Street/Rock Ridge Road intersection,High Street and the B&M Railroad culvert. To mitilgate downstream flooding problems, the Fuller Study recommended two Bret pond, detention basins located on the Merrimack campus. However, the proposed basin sizes,shapes, and locations conflict with developable saes as proposed in the College Master Ilan. Therefore, it is the goal of this study t evacuate the erty rook watershed as it relates to � Merrimack College campus, the Gou ge Master Plan, the Elm Street ock ridge Road p roblem area, and develop a rnitig ation plan which benefits both the Town of Andover and Merrimack College 1,2 DESIGN OBJECTIVE Objectives where established by the school and the Town of Andover Department of Public Works for a stormwater management plan. They are as follows: i Y } 1. Solve current flooding problems experienced by residents of Rock Ridge road. 2. Mitigate increases in peak flows attributed to full development under the Merrimack College Master _ Plan,, { . Arrange an accounting system that enables Merrimack College to earn peak flow reduction credits'� w through the construction of both detention basins,and draw on these credits for future campus devrelopment projects. f The Fuller Study was used as a reference during preparation of this report. Though the watershed nomenclature is consistent bet eeix both reports, this sttidy was completed with a greater emphasis on detailing contributing watershed areas on the college carpus. 113 METHODOLOGY The Natural Resources Conservation Service(NRCS), formerly the Soil Conservation Service CS , Technical Releases No. 20 and No: 55,were used in this study to model the hydrology of the watershed. T6 stormwater management system was analyzed for peaks up to the too-year, 24^hour,Type III storm event for northeastern Massachusetts. Total rainfall amounts for each design storm are as Follows: Type 111, -hour~rainfall: 2-year 3.36 inches I 0-year 5.04 inches -ye r- 5.76 inches 50-year 6.24 inches I o year 6.40 inches TR-55 was used to establish CN and Tc values. TR-20 was used to create hydrographs which could be reach routed as well as routed through multiple detention basins_ 1 3i SOURCES4 1. k; Berry Brook Drainage Study by Charles E. ulleE-, 1/9 (Fuller Study) 90 Merrimack Cone Andover Consulta .ts, �I • Drainage Anal sus, � record dos�g and as-built drawings.• a _ • Visual observation s rFl Ji'k1'r L EXISTING RUNOFF/DRAINAGE CONDITIONS e�der r Watershed, rhkoh.flows both overland and thr u h s e study r�alye I�- acres the r �, street, and a the clue taus, rr--c , us, Rock midge Road) a series o our drains located s g • rain. e system consisting of " reinforced bv t o r t t � Street. a edge load has a closed erou catch basins. During large storm events the system concrete � e, eer�a� ed �pipes and 'a ent homes. study previously Performed b causing flooding in the street and yards f the add there srcbages, the size the drain rithin Rock Ridge Road,but Andover Conultao.t , Inc. rear ,rr�errded increasing� and.the Shaysher� • increasing eat .o rates t the downstream et�and resource areas is concern regarding incr g h Ridge load�s not n alternative. River, t is a s u . d that increasing the size the drain within Rock w r On-Site Watersheds • watersheds, the Berry Brook Watershed and the The I�erriro��College rn �x drains t two separate w � pan o campus es not evaluate the Rogers Brook Watershed, The sect o er� Brock Watershed This study d ft via slope less than Watershed is 1 2 acres. This area is relatively flat it a g �th�r� the r� Brook orth eotiori o the at � hed�to I � and ranging in gradesfrom elevati n o ±at Elm Street at the r� _elevation 4 ±at the south section of the watershed. ''here are wetlands located in various locations throughout the watershed area, �� Massachusetts", the soils found n the Campus are Paxton According t the for Survey e County, - e (\VrA and�s which are Rid bur and Li ester(RiA), and Woodbridge Pa , rdgebuty and Rd g i in drop is Soil Grc C, and Whitrna Mg), rh�ch.� identified as Group � (See Figure � o�as � large areas open s ace used o r recret� rra�and The corn s is rr�,crate[y de�reloped aid.cantasns l g competition athletics. 1. . off-site Wcatersheds . n� an ire watershed rnas . area M-I C is south The Campus receives ,o� from two general areas see acco a he Ca mp Lis o Highland Road and is comprised of five rib areas. The second area, I ��-I , i out of t beyond Route 125. " res respect t the Fuller study' lude changes t the overall surface area, CN and�`c. 'ravel Revisionsvet � . ` rated into the anal si through�rec .routing. Sn dines thr u downstream sub-areas were inc r o y entiled breaks watershed areas�wrt in M-1 C are identified a M-I C--1, �r��- , etc. the sub-areas are r - with reference t �a�rr entitled, in the larger area caused roads. Watershed.delineation was completed "wetland areas a ir Andover, M a sac usetts by Terrain IrLvetigario n, I . ," and rec rd S ite surreys. • culvert to the next downstream watears ed.. To be conservative, Each sub-area in �.--�.0 dIscbrges through detention basin located the restrictions imposed on the flow by theculverts under the roads a well a l de in area M-I D were ignored, 2 Off-Sited(we-sl"0 Alcott Warh ocared ein channel wet'-a"" reaches ' a occet . the south and oath o the football earth bean.an o origmates o retlaa area � ,- .. `here is n , e berms rte progress to largeethedaete M ` flow theme is are the era t ray �� � .� � a.a occer �e� s. ter �� t t he tray detention.are to a spa natural 'o the oot a s + discharging rgi .� as retd and laying Jets and. or searat'n.g etan y es .& is ��� between � I - edam � ar er s - o the field. � 'o anae • These etermine weir. canot ° ue n �r • ' arn-er o r was o ra hs ere th rk • e a aoit n the berm t rrnwatcr yr arc isc arg i -r e e � weda. then ec .e r yen n assumed � eh � e ,.oc �.for the erIan � was stage/Storage elevations with atio to .ced aou�at � ea c fl o is R ,w t ettan � an cad • ��st � even .ate throngs the .t' ns a e r ng she i � t a •n t vIsuaI o s ry Bch runs e .e �h o ,finned.,agar �) drain pipe,wh . there are u t tens one 1 C t6 n, t possible e football. it erg record inorma ctc� e ponying at t .e.e ge the 'i � based o these mere n( .1e u ern edge the eng area. rth th �e�ncue within nheon the e a otts from �P e We o the 'elcs, a tag rch also s n ct1axlci to the ,o arrnct se s and seco the otll and soccer Oka, practice ears er the Itctshe re football gold., 's o �� �' • via� nor o flow contra e is to �o Witch ins. storratet - cis 'oota , soccer rain conec o farmer s drains., M. The three fled e net to a.systems er}s �a�n system soccer herds, act as a` n eurnab con to to the sane arm she oor and s c cut hro gh r'sun e tonne the crest side o en t o traf is island twins,which relan area ado e two e a combined r�th • Iasi �n �u� s kd practice-; het o this. severe storms eet . basin. he out on � overflow We�rduring Rural detente Bch `unctions a .n t . Campus (area • n oua.r ,which trl dra"nage fro woes in �� n� � e n Duet additional t the drainage sytcn re a • , collecl a� . .fit this Porn used t establish a ra coridnnc n the st of the irn e stem that was thc 3 a s hole nor n o the c ra.t g } d .in uncjc a �,j reaching It- t �s sectlo yea, th the _� -6 , . e 2e MCP rain de ration i � er and size to one for the Dot , ded in this anal s ur a relationship �� • oh ties was n. t eta etoragel a airy o the ' r torwater � g off. the t gage c �' co 'boar piped ant over terection of uet co11ecting adds � . .t the c Row - -> ' • heath ocg o (areas concrete l - ` co nt�n �e }� o rho �� rep o� e he 2 )) drain d the ad acent neig 11 e to 36 do scha.tge to a th the Campus an ' crease from the a e� � '� then turps� to ass as os rret, the roatey and eet r a P n u er of eeer tre oc Ridge- a` t under Elm�tr connecting . a+ moderate stori m "" � eProceedssouthwest net continue v,�e � unders� ed for even Me�� �' streec. �s channel c �d load� flooding in th street 1 northwest o The dram 0 the- ttee-tl cau a,nre ,as ,en River. win backs "nto the� i - she dr - * row- vets as .Channel) t flows toward schagg�n conditions) rh area i hat,arl her oocting s sce ve ts. s th is along the row through the Pipe o the ��es� .en rand�r�steac o g . pis. end she far r ro ove fed�xr t , analysis. stor water to o 1�ch }=co vey g s s Overland e� brook do rnstrearn � � reach the� � _ a d�shr �n to � - � a e rorn route �. ath the rig . o 'Portions orn g - awe t south belle 2 - in Route 114 dra 0 the ana.lYs i , t o rhlit e 4 3 1,6 PROPOSEDRUNOFUDRAINAGE-CONDITIONS 1. .1On-Site Watersheds �- Note that the following phase'designations are not to be considered the date of onst'r ction completion, but rather reference the mitigation provided by construction of each detention basin as summarized in this report. pioposed 1999 The year, 1999 scenatio assumes that the"Football Field Detention Basin" is constructed only in the first phase* A new landform is proposed to create a more defined northern edge and a conventional outlet structure a ded to control flows during the various story events, The existing tennis courts adjacent to the football field will be removed and the area regraded to provide additional storage. Pro, d 2000 The year 2000 scenario assumes that the"Elm Street Detention Basin"' is con.sti cted in the second phase, with the Football Meld D etendon Basin in operation, Little will change in terms of newly developed area. 4 Instead, do ngradie t carpus ratersheds will be redirected away from oc edge load and routed t the G Flat Street l eiention Basin site via a " dla. drain'. The Elm Stre t Basih essentially qoritrols flows from campus watersheds dow . tr am of the Football Field Basin. To complete this.work,a drainage easement is required from the owner o 'Andov'er Street to convey stofmwater to the Elm Street site. r - o. x Proposed 2020 The year 2020 scenario assumes that both detention basins are in operation, and the campus is fully i developed as proposed in the Merrimack College b4a ter Flan. Both detention basins have been designed to mitigate the increase in peals flows attributed to'f ll development under the Master Plan,while still providing flooding relief to the residents of Rock Ridge Roach and areas downstream of the carpus, 1,6v2 OffTSiteWatersheds i t has been 1nd1c ted by the Town of Nort .Andover-D PW that the upstream po rnon of the watershed is at or close to full build-oust. Any future development ent that may occur is expected to implement a storm aster management plan of its own and not impact downstream at-easy 1.7 FOOTBALL FIELD DETENTION BASIN The hydrology of the.u'pper part of Berry rood Watershed is such that most of the sub-areas upstream of the Campus flow through small drainage channels and are collected bar the e to siv wedan at the south end o the Carpus. This wetland detains the rurt f` before discharging to the football field area. This area in turn detains the flow again before discharging to the drain in Rock Ridge Road. The adjacent, nog.-bordering wetlands west of the football field flood during periodic storm events. By inc reasl ng the ability o f this area to impound water through co ns truction of the berm,'the wedands will flood for a longer period of time. The follo rl g table sum-marizes flooding impacts associated with this additional } flooding. Approximately o. '5 feet-of freeboard is p rolded during the 1 oo year flood elevation within the basin,under 2020 condltions. s I t F s Fables 1 : Effects of Increased Flooding on the Football Field Wetlands 2-Year I O-Yea r 2 -Year 50-Year 1 -Yea r i Proposed 1999 &2000 Storm Storm Storm Storm Storm ExistingElevation 22 .93 228.19 2 8. 4 228.43 �� .� i } Pro sed Peak El vatio ( ) 22 - 2 22 .16 229,, - �� 230.40 Additional Depth of Flooding (ft) 0.89 O�97 1.46 1.91 1.95 Pro ose �Meets Existing Peak 12.9 �,95 12. 12. 12.55 Elevation @ Time=T, (hr) Proposed Drops,Below ExistingPeak 33. 8 34A 39-30 42.23 43.2 Elevation @ Time=T2 ( r) Time Associated with Increased 2 .83 2 73 26.55 29.63 3 .7'3 Flooding:T T, (hr) L •"a 1 2-Year I OmYear -Year -Year I - eon* Proposed 2020 Storm Storm Storm Storm Storm r Existing Peak Elevation 226.93 228.19 22834 228.4,E 228.45 Proposed Peal{Elevation R) 228,00 229.46 230-15 230.62 23 . 8 Y Additional De th of Flooding 1 w07 1.27.. 1,81 2.19 2.33 Proposed Meets Existing Peak 12,50 12,68 12.53 12.45 12.41 Elation @ Time=T, ( r) Proposed Drops Below Exisfing Peak 35*4 37.5 , 42,15 45.20 4 A #1 ` Elevatio'n @ Time =T, (hr) Time Associated with Increased 22..90 24.82 29.62 32. 5 34�69 Flooding:T-T, (hr) , Y Table 3: Flows to Rock Ridge Road r, # hp I S Flogs ( S 2 -Year I -Year 2 - ec r -1Cear 1 -year Design S torm Storm Storm Storm Storm Storm Existing Conditions 81.10 131.49 153.41 168-07 172.96 k 1999 Conditions 6 *12 12 .9 1456 �1, 16634 r 2000 Conditions 2144 2. 5 52,50 58.68 60.67 2 Conditions 16-96 32.5� 39.3 43*54 .75 k` 7 r l L - i 4 S F i a -f - i i i 7 s 3 - r r i r 4 } r ELM STREET DETENTION BASIN 'his basin area will be located on Merrimack College owned property northwest of Elm Street. The sire is a undeveloped,wooded ridge nestled between'rwo intern itrent streams. A. 8'� 1�. ra�rz �lil olt t campus ss-the campus to the airy driveway. From this location the 4 " runoff, traversing southeast to northwest acro dtai a will transition to two 36" dia. drains to avoid utility cro si ng co icts,cross Elm Street,#4 85 Elm trect, and discharge to the b sin area. r4 i L { b sj ,with a capacity approximately . ac-ft will di cbaf e via 36" dia.. outlet co trol� l�ror�n the tl t storrnwater will be conveyed to Berm Brook do nsti eam of Elm Street via a comb inatio n rock lined. 3 and grass Tuned channel. Approxiiiaately 2.0 feet of freeboard is provided during the 100 year flood elevation s within the basin. 10.9 CONCWSIONS A As stated at the beginn'ng of this report, the design objectives fbr this project are as follows: solve current flooding problems experienced by residents of Rock Ridge Road. . Mite are increases in peakflows attributed to full develop .ent under the Merrimack College Master Flan. 3. At-range a an accounting system that enables Merrimack College to earn peak flow reduction "credits' through the construction of both detention basins, and draw on these credits for future carnpus development projects. The results of the hydrologic analysis prove that th'rou.gh the construction of both the Football Field and Elm tr et etent Basis, there ar-e significant benefits for both Merrimack College and the Tows of Andover. With respect to fall development under the College Master Flan, for the 25 year design store peak flow rates within Dock Ridge Road will be reduced.74%. The remaining 6% of flow to Rock Fridge Road,which includes 17cfi of controlled flow from the football field and 28c s of uncontrolled flow from the adjacent neighbor-hood,still exceeds the 25 year storm design capacity of the existing drain, approximately 23ofs, but has been greatly improved. r, Sites downstream of the carps along the Berg Brook flog path also experience benefits from construction of the detention basins. For the 25 y year design storm, flows downstrearn of the campus will observe a 1 o reduction In peak flows,and for the 10 0 year desigrn storm a 21% reductio n f n peak flows,which wlH held F ease periodic flooding experienced by these areas during severe storm events. 4 The of rementioned peak flow mitigation within Rock Ridge Road and downstream areas assume full -development under the Master ter Plan. There will be even greater reductions la the short term. As of this report, Merrimack College i scedul*rig development of -�projects on campus in the next few dears as art of their strategic plan. Construction of the detention basins will provide peak flow mitigation for these and other-projects not yet scheduled for development,while providing both short term and long term benefits to the tows. ' :V 18 9 7.0 0 pro rn grn t\c n ineeAgIf rp6 rep ort.doc t 4 6 F}� L� i S , A Tune 13,2001 Mr.James Greer,Administrator Andover Conservation Corission 36 Bartlett Street,Town Hall Andover,MA } re. Mem*rnack College-Stor nwater Management Plan SA#71897.01 Dear Jinn: As discussed at our public hearing on May 1 ' ,Sasaki has reanalyzed the hydrology for the Merrimack College—Storruwater Management Plan assuming a percentage of impervious-coverage in excess of that previously analyzed under the Hater Plan for the affected campus watersheds. Thishas been done to establish a stor water peak Sasaki��la eInc. runoff"account" for the College t'o draw upon for future campus� development. 64 Pleasant Street 1. Summary analysis concludes that for a 2 %increase m impervious coverage over what was 02,472 USA previously calculated under the Master Pfau—Year 2020 development scenario,the total peak rate of runoff generated by the campus prior to rtigationdeteton ism. 1 6 17 9263300 Under this 8cenario, the ancillary benefit for the Town of Andover regarding peak flow 617 924 2748z; reduction via construction of both detention basins is approximately . It should be �.sasa ixor f' noted that the emergency spillway elevation for the Football Field Detention .sign shall be raised ar pro imat l .2*,from 230.8 to 231.0. A copy of the computations is - included for your reference. Y . . Draft Order of Conditions—Special Conditions As also suggested at the May 1 Conservation C nunissi n hearing,Merrimac College proposes the following language to be incorporated into the Order of F; Conditions to set protocol for ad "nister.ii the ak flog accounting system. ste . 1. The Town of Andover and Merrimack College agree that the College will construct two detention basin sites for the.purposes storrn water mitigation for •development of the College blaster Plan. .As directed by the Comm ssion,the Town of Andover will re0eive the ancillary benefit of reduced peak stun water runoff downstream Of the detention basin sites. This is achieved through overcompensation and reduction of peak runoff rates above and beyond what is required in the Massaebusetts Department bf Environmental Rotection—Stormwater Management Guidelines under full implementation of the College Master Plan. 2. It is understood that the timefrarne for full build-out of the College Master Plan is approximately 30 years. Y June 13,2001 Page 2 . Construction of the two detention basin sites will provide mitigation for increases in peak runoff rates associated with future carpus development projects. The total increase in post-development peak rate of runoff with respect to existing conditions under the Merrimack College Master Plan, with . contingency allowances,is 62 cf . It is understood that this total peak flow increase is mitigated through the construction of the two basin sites,and that this value will serve as the credit upon which Merrimack College may compensate future development and resultant increases in peak runoff rates. . After issuance of this Order,future Merrimack College development projects needing permits and approvals from the Town of Andover will require a estimate of the increase'in peak rate of runoff for that particular project. This estimate will be submitted to the Comrrdssion for review and upon approval, i will be subtracted from the total remaining credit existing at the time of the application. The Conmission will then issue a letter to the College stating their understanding of the peak flow credit remaining for future de eloprnent by the College, Sasaki Associates Inc. . Merrimack College is responsible for the construction maintenance and monitoring of the detention basin sites so that optimal performance of the basins is maintained. Merrimack College has the right to modify the detention basins and associated drainage structures for the purposes of increasing detention efficiency and/or to merge the basin sites with future developmerit projects. Detention basin modification is subject to review and approval of the Commission. . The Elm Street Deitention Basin is designed with a 725 if water quality swale to convoy storm flows and to provide.pollutant attenuation. Mern*mack College has the right to take credit for the water quality wale as.-a Best Management ement Practice MP for future development projects. Use of the grater quality Swale for pollutant removal is subject to preview and approval of the Comnussion. • If you have any questions or wish to discuss the draft conditions,please do not hesitate to contact nee at,617-923-7162 incerely, Pet JL o as . Pro.ect Manager o: David preen,l be Copp a; Mem"mack College John Hollywood,Ginger Fagundes, Mo Gomez;Sasaki �x S -A S' A' K June 1 ,2001 Mr.James Greer,Administrator Andover Conservation Commission 36 Bartlett Street,Town Hall Andover,MA r : Mem"mack College-Stormwatr Management Plan S,A#71897.01 Dear Jinn: As discussed at our pblic hearing on May ` ,'Sasakl has reanalyzed the hydrology for the Merrimack College-Stormwat r Management Plan assuming a percentage of R.i pervi ns coverage in excess of that previously analyzed under the faster Plan for the affected campus watersheds. This has been done to establish a tormater peak Sasaki � Inc. runoff"account"for the College to draw upon for future campus development. 64 Pleasant Street The analysis concludes that for a 2 increase m imperious. overage over what was 02A72 USA previously calculated under the Master Plan-Year'2020 development scenario,the total peak rate of runoff generated by the.campus prior to rnitigationdetention ism, o Under this 8cenwio, the ancillary benefit for the Town of Andover regarding ea flow 617 924 tt: reduction via construction of both detention basins is approximately . It should be { - noted that the emergency spillway elevation for the Football Field Detention Basin shall be raised approximately .2",from 230.8 to 23 1.0. A copy of the computations is included for your reference. r 11. Draft Order of Conditions—Special Conditions .As also suggested at the May I Conservation Convnission.hearing,Merrimac k. College proposes the following language to be incorporated into the Order of { Conditions to set protocol for administering the peak flow accounting system. I, The Town of Andover and Merrimack College agree that the College will construct two detention basin sites for the purposes storm water mitigation for •developm nt of the C liege Master Plan. As directed.by the Comnu*SSiOD,the Town of Andover will receive the ancillary benefit of reduced Teak storm water runoff downstream of the detention basin sites; This is achieved -. through overcompensation,and reduction of peak runoff rates above and beyond what is required in the Massachusetts Department f Environmental :Protection—Storrnater Management Guidelines under full implementation of the College Master Plan. It is understood that the timeframe for fall bulb-out of the College faster Plan is approximately 30 years. June 13,2001 Page . Construction of the two detention basin sites will provide mitigation for increases In peak runoff rates associated with future campus development projects. e total increase' n post-developmetit peak gate of runoff with } respect to existing conditions under the Merrimack College Master Plan, with contingency allowances,is Gam, It is understood that this total peak flow increase is mitigated through the constmetion of the two basin sites,and that this value will serve as the credit upon which Merrimack College may compensate future development and resultant increases in peak runoff gates. . Auer Issuance of this Order,future 1 em'ma k College development projects needing permits and approvals from the' own of Andover will require an estimate of the increase in peak rate of runoff for that particular project. This estimate will be submitted to the Corms sion for review and upon approval, will be subtracted from the total remaining credit existing at the time of the application. The Co'rfamssion will then issue a letter to the College stating k their understanding of the peak flow credit remaining for future development by the College* Sasaki Associates Inc. . Merrimack College'is resp onsi le for the construction maintenance and mon t r'ng of the detention Basin saes so that optimal performance of the basins is maintained. Merrimack-College has the right to modify the detention basins and associated drainage structures for the purposes of increasing detention efficiency.and/or to merge the basin sites with future development: projects. Detention basin modification is subject to review and approval of the. Commission. . The Elm Street{Detention Basin is designed with 25 if water quality swat t convey storm flogs and t pro rid pollutant attenuation. Merrimack mac College has the right to take credit for the water quality s we as.-,a Best Management Practice MP for future development projects. Use of the water quality svale for pollutant removal is subject to review and approval of the Comrru' si n, 4 f you have any questions or wish to discuss the draft conditions,please do not hesitate to contact me at617-923-7162 incerely, V0 tA. o as J. nett,PE- Pro'Pro' t Manager cc: David re en,�W opp a;Merrimack College John Hollywood,Ginger Fagundes, Mo Gomez; Sasaki r r� _ s II L;I. � � ��r � ♦.;�`�L.rG��E1�i�, - alf��x � ; V Y. r I ��. ��f •�.<,/-- i \'[6 v�r-;_1 \f� .z 1�✓'/ �r��r �yx/z r i f eft �I I, f _It�jLl'� °•'{ 1 'i n ls��S�t��'♦` ��/1`�s fFr" _ r� �/i r J!' f 1 V-t 1;! - \� r� / t r•";/"Y?'`j�-�' �wl�x Ile ,erlx-go- VISIONx 1 /R I !!II r1 I\SS r /.; ! 74._ - •� rr%rs ^ + �� {` �'Jj �\,\ ti`!+f \/�•r-'� -, /` - I 1 f- `�L"��i.�'rY =�., - ���. .. � 1 10111++ /�^tom _- - _�F {J/-. /r 1=r♦ .,'4 x�/ yF.✓'�, I , J- i,r / ,!.!':• 1 i. .����_G- /-` � eL\i� / _,r s� rrfl fix, - -'G fz e 7777 .5� , M � 4 � / / \ '�'�f !}!f/ i_ �,- �! -iI/ ..,sF� 11 �•'3 '€ -�� ,�yr/f/, � F /J/ v 16.29 Acres y_ •�� C'/L/� /////�i'/�♦-! ♦r - C: 11.I r / z3 -r;; - �`' �i .. -cw/ft Fi ��� L ��� \ �✓ /� _�s,.Gtta�.i.. �Sri//�l l _ '�, - _ / r. � s��� ���� �'I" `'`k'`�z, "IY{T-���-L •A _/'\\, ��j7� /' J i l//f[f�� 'r -� �`f' r f ten'' ./ ���n�. _ i;.ilF l�/ n .r•� - �\ �i.� - S20• Acre �f/ r CYp r�f r/11 r I\!1\♦\ r _ f - I 1 r -/rx rf f'�i-f. �'-- - - - r �fdi' �`( - _,�v; r '*• t% f Yf/\ t --', r ��r/r�7 f�. �, ,- - .f,=;3y1 r' �'a�✓� � i� 1 / -r l / -/ f �r :I r ;�v/ � f- ;�� '� ��� - s rx , -_ ,'1/� i TLAh! •� / Ys c .� r/• E 1 p ,..:. 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M—ID �S.@D Arms t • � I 3 3 3 1 [drainage Study 2020 Watershed Plan April 1999 OVA L7' l id' 300' i a 4 * ;4 FILE COOP"kY Massachusetts Department of Environmental Protection DID File l~ b f: Bureau of Resource Protection -Wetlands 9 -0 WPA Form 6 � order o Conditions "P i D P �y Massachusefts Wetlands Protection Act M.G.L. c. 131 §40 A. General Information Important: When filling From: out forma on Andover the computer,, Conservation Commission use only the . �` tab � This issuance i for(checkones - rave your cursor- o order Conditions not use the return key. 0 Amended order of Conditions To; Applicant: Property Owner if different from applicant): x M.25,01mack College same Name Name _316 Tum Ike Street Mailing Address bailing Address North Andover MA 01845 1tyrrown State Zip Code City/Town Mate Zip Cooke I Project Location: 315 Tumpi a St et and Elm fteet Andover Street Address Cftyf ro n .and 1 5 and Assessors Map/Plat Number Parcel/Lot Number 2. Property recorded.at the Registry of Deeds for: } Essex North DistHot 30 329 County F Book Page A Certificate if registered lard) u 3. Dates: 04-26-99 Julv 17, 2001 October 5, 209 E)ate Notice o of Intent Filed ' Date Public Hearing Closed Date of Issuance } 4. Final Approved Plans and Other Documents aftch additional plan references as needed): Merrimack College 6tormwater Minagement Plan, Andover and North Andover 07-02-2001 rev. (Cl-_Ij CI- , — , C ^ F 3- i —2 • .4— Date Supplemental Calculations: H drol-' is Analysis qdjqsfing Year 2020 96- 9-2 01 . Final Plans and Documents Signed and Stamped by: Name 6. Total Fee: t $525.00 (from Appendix :Wetland Fee Transmktal Form) WPA Farm 5 1 of 7 Rev.02ADO f k 2 F 4}d� C Massachusetts Departmentof Environmental Protection DEP File Number: Bureau of Resource Protect"ors -llela trd 9 - 7 Provided by DEP PA Form 5 Order of Conditions Massachusefts Wetlands Protection Act M.G.L. c. 131, §40 F B. Findings Fi din s pursuant to the Massachusetts Wetlands Protection Act: Following the review of the above-referenced Notice of latent and fused on tine i forr att on provided in this applioadon and presented at the public hearing,, *ls Commission finds that the areas in which work Is proposed Is significant to the following interests of the Wetlands Protection Act. Check all that apply: 0 Public Water Supply Land Containing Shellfish ED Prevention of Pollution [:J Private Water~Supply D Fisheries El protection of Wildlife habitat x Groundwater Supply storm Damage Prevenflon JZ Flood Control Furthermore,this Commission hereby finds the project,as proposed, is. hem one of the foI o Ang boxes) Approved subject to; LE k the following oonditions which are necessary, in accordance with the performance standards set forth IN the wetlands regulations, to protect those interests checked above.This Commission orders that all work shall be performed in accordance with the Notice of intent referenced above,the following General Conditions, and any other special conditions attached to this order.To the extent that the following co ndibons modify or differ from the ptans, specifications,catiorns, or other proposals submi ed with the Notice f latent, these conditions shall control. { Denied because: El the proposed work cannot be conditioned to meet the performance standards set forth in the wetland regulations to protect those interests checked above.Therefore,work on this project may not go forward unless and until a hew Notice of Intent is zc omitted which provides measures which are adequate to protect these intents, and a final order of Conditions is issued. El the information st bmltted by the applicant ils not sufficient to describe the site,the work,or the effect i of the work on the interests identified in the Wetlands Protection Act.Therefore,work on this project F may not go forward unless and unfil a reprised Notice of Intent is submitted which provides sufficient information and includes rnea;sures which are adequate to protect the Act's interests, and.a final s Order f Conditions i IssUe .A description of the specific�I�nformation h ich iacRing and��rh It is necessary is attached to this Oeder as per 310 CM R 10.05(6)(c). General Conditions (only applicable to approved projects) r 1. Failure to comply with all condItIo s stated her ln,and with all related statutes and other reg lat ry measures, shall be deemed curse to revoke or modify this Order. 2. The Order does not grant any property rights or any 6xcluslve privileges; it does not authorize any injury to private property or invasion of private rights, ` . This Order does not relieve the permittee or any other person of the necessity of complying with all other applicable federal, state, or local statutes, ordinances, bylaws,or regulations. 0 { WPA Form 6 p0 of Rev.02W gx Massachusetts Department oEnvironmental Protection ,� il umber:' Y� Bureau of Resource Protection -Wetlands 9 - 60 Provided by DEP WPA Form 5 �q Order of Conditions i1 as achuse is Wetlands Protection Act M.G.L. c. 131, §40 B, Findings (cont. 4. The work authorized hereunder shall be completed within three years from the date of this order unless either of the following apply. t a. the work is a-maintenance dredging project as provided for In the Aot, or h. the time for completion has been extended to a specified date more than three years, but less than five years,from the date of issuance. If this order Is intended to b valid for more than three years, the a ctensi n slate and the special circurnstan a a warranting the tended time period are set forth as a special condition in this Order. } 5. This Order may be extended by the issuing authority for one or more.periods of up to three years each upon application to the Issuing authority at least 30 days prig to the expiration date of the order. 5. Any fill used in connection with this project shall be clean fill.Any fill shall contain no trash, refuse, rubbish, or debris, including but not limited to lumber, bnocks, plaster,wire, lath, paper,cardboard, - pipe, tires, ashes, refrigerators, motor vehielesIr or parts of any of the foregoing. . This Order is not final until all dminl trait ve appeal periods from this Order have elapsed,or if such an appeal h s been taken, until all proceedings before the Department have been completed. 8. No work shall be undertaken until the.Order has become final and then has been recorded in the Registry istry of Deeds or the Land Court for the drstrlct in which the lard Is located,.wlthin the chain of title of the affected property. In the case of recorded land,the Final Order shall also be noted in the lie ist "s Grantor Index under the name of the owner of the land upon which the proposed work is to e done. In the case of the registered land,the Final Order shall also be noted on the Lam Court Certificate of Title of the owner bf the land{upon which the proposed work Is done. The recording Information shall be submitted to this Conservation Commission on the form at the end of this Order, which form must be stamped by the registry of Deeds, prior to the commencement of work. . A sign shall be displayed at the site not less then two square feet or more than three square feet ion size bearing the words, 5 Wassaohus tts Department of Environmental a tection"[or,OMA DEP`l �'FileNumber90—O750 10, Where the Department of Environmental Protection is requested to issue.a Superseding order,the Conservation Commission shall be a party to all agency proceedings and hearings before DEP. . Upon completion of the work f sbribed herein,the applicant shall submit a Request for Certificate of Compliance ICI PA Form A to the Conservation Commission. ion. . The work shall conform.to the plans and special conditions referenced in this order, . Any change to the plans Identlled In Condition#12 above shall require the applicant to inquire of the Conservation Commission In writing whether the change is significant enough to require the filing of a new Notice of Intent. . The Agent or members of the Cons rvatiori Corr mis lon and the Department of Environmental - Protection shall have the right to enter and,aspect the area subject to this order at reasonable hours to evaluate compliance with the oondiffons stated In this order, and'may require the submittal of an data deemed necessary by the Conservation Commis ion or Department for that evaluation. x WPA Fo Rev.O f a t 4 • lassa� etts De rtmen nv o rental Protection E sir Number: . j* Bureau of Resource Protection-Wetlands -oo z Provided b DE : WPA Form 5 � Order of Conditions Massachusefts Wetlands Protection Act MA L c. 131, §40 B. Findings (cont. 16, This order of.Conditions shall apply to any successor In Interest or successor in control of the property subject to this Order and to any contractor or other person performing wofk conditioned by this Order. 16. Prior to the start of work, and if the project Involves work adjacent to a Bordering Vegetated if etiand, the boundary of the wetland in the vicinity of the proposed work area shall be marked by wooden stakes or flagging. once In place,the wetland boundary markers skull be maintained until a Certificate of Compliance has been issued by,the Conservation Commission. 17, All sedi entabon harriers shall be m intaln d in good repair until alUdisturbed areas have been fully stabilized with vegetation or other rears.At no time shall sediments be deposited In a wetland or Y water body. During construction, the applicant or his/her designee shall inspect the erosion controls on a daily basis and shall r move accumulated sediments as needed. The applicant shall immediately control any erosion problems that occur at the site and shall also immediately notify the Conservation Commission,which reserves the right to require additional erosion ardor damage prevention controls, it may deem necessary. Sedimentation barriers shall serge as the limit of work unless another limit of work line has been approved by this order. Special Conditions(use additional paper, if necessary): i See attached sheets for special conditions and findings. +mow i Findings as to munlcipa nbyla r or ordinance t Furthermore,the .hereby finds (check one that applies): . onservaUon Commission El that the proposed work cannot be conditioned to meet the standards set forth In a municipal ordinance or bylaw specifically; Name Munlelpal ordinance or Bylaw t Therefore,work on this project may not go forward unless and until a revised Notice of latent is submitted which provides measures which are adequate to meet these standards,and a filial order of Conditions is issued. El that the following additional conditions are necessary to comply with a municipal ordinance or bylaw, specifically: Name municipal Ordinance or Bylaw The Commission orders that all work shall be performed in accordance with the said additional i ' and w ' ` Intent referenced above.To he extent that the follow conditions conditions a with the lotro f n r t g modify or differ from the plans,specifications, or other proposals submift d with the Notice of Intent,: the conditions shall control. - r WPA ForM 5 Page 4 of 7 Rev.{ z . i ,..,.}; 1. PINDINC.T-NOTICE OF RMSDICTI N UNDER THE MASSACHUSETTS WE-MAND PROTECTION ACT, M.G. .C. 1317 S.40. The Andover Conservation Commission hereby ids that all or part of the property on which the work authorized by this Order is proposed is subject o j uarisdiction under the Massachusetts Wetlands Protection Act,M.G.L.C. 13 1, s. 4 0. The owner s hereby notified of his or her responsibility to comply with the previsions of that statute. This condition shall remain in effect n pe p tufty wd shah survive the issuance of a Certificate of Compliance. :f 2* TESTIMONY. During the course of the Public Hearings on this project the Andover { Conservation Commission considered and weighed extensive written and oral testimony, cludg the following, The Applicant submitted the following materials prepared by Sasaki Associates, Inc.: } 2.1 Document entitled"NOTICE OF INTENT—APPLICATION FOR MASTED. { * ST RMWATER1'1 ANA GE PLAN%,dated; April 26, 1999. 2.2 Engineering design plans. 2.3 Hydrologic Analysis. 2A Document a .titled'W TILE of INTENT—APPLICATION FOR MASTER STORMWA.TER MANAGEMENT T PLAN,REVISED SUPPLENMNTAL HYDROLOGIC CALCULATIONS"; revised date; June 1, 1999. 2.5 Letter dated August 11, 1.999 from Douglas J. Hartnet,PE(5 pages,responding to the July 14,1999 peer review letter from Judith N tsch Engineering,Inc.). 2.6 APPENDIX—A, STORM WATER MANAGEMENT—OPERATION AND .iMAINTENANCE PLAN FOOTBALL FMLD AND ELM STREET DETENTION I BASIN (2 Pages, dated August 1 , 99 . 2.7 Tree pages, dated 11 Ault 1999 prepared by Sasaki Associates,Inc.: ELEVATION VS. DIS AR rE—FootbaU Field BaS14; ELEVATION VS. DISCHARGE—Elm Street Basin; and TSS Renoval Calculation—Elm Street Detention Ea . 2.8 Letter dated April 17,2001 from Douglas J.Ha-tne E 2 pages, spa izmg events since the last Publi6 Hearing,peer revlo v,design alternatives and outlining the pr ject's design objectives With revised engineering plans. 2.9 Letter dated April 17,2001 from Douglas J.l artnet,PE(1 page,transmittal o revised F hydrologic calculations and un �spreadsheet, and sum anzmg plan changes,with revised plans dated Rev.April I I, 2001 . 2.10 Letter dated July 2,2001 from Douglas J. Hartnet PE(1 page,transmittal of revised plans dated Rev. July 2,200 i). 2.11Detail sheets(2) describing the location and methods to be utilized for a temporary haul road (plan view and cross-section)"Haul Road Across Wetland', } Judith Nitsch Engineering, In.c, (acting as consultant to the Conservation Con=sslon)submitted the following: 2.12 peer review of the engineering plans and calculations,July 14, 1999(consisting of 6 pages). 2.13 Peer review of the engineering plans and calculations,September 7, 1999 consisting of 5 Pages)• t a a F f . n a _.R W 2.14 Peer review of the engineering plans and calculations,October 1, 1 (consisting of 4 pages). 2.15 Peer review of the revised engineering plans,April 2 ,2001 (consisting of 2 pages4 Interested partiet submitted the following. 2.1 Letter dated May 7.2001 from fir, Kevin J. Porter of 8 westwind Road) conceming p tential eff cts of the proposed project on flood levels at Elysian Drive and Twin Brook Circle. . MWAL APPROVED PLAT AND OTHERDOCUMENTS.Wok shall conform to.the plans :r referenced' n Page I of tWs Order and to the most recent of the above-referenced materials submitted by the applicant on file with the Andover Conservation Commission). . MASTER S ' RMWATE MAMA. x I�MN 'PLAN. This project consists of the proposed construction of a campus-wide stonnwater drainage system, including two stonnwater detention basf . The applicant has Mated the design.objectives for this project as follows: I. Solve current flooding problems a penen'ced by residents of Rock Ridge Road. 2. Nfifigate increases in peak flows attributed to full development under the Merrimack College Master Plan. 310 Arrange an accounting system.that enables Merrimack College to c=peak flow _ reduction"credits"through the construction of both detention basins,and draw on those credits for future campus development projects. The-appli a ,t and the eonms ion understand that this Order of Conditions establishes-a Y: A mechanism by which the applicant may m" future utilize the surplus capacity created by the prposed construction.. S. PROTOCOL FOR ADMINISTERING TM PEAK FLOW ACCOUNTING SYSTEM. 5.1 The Town of Andover and Merrimack College agree that the College will construct two detention basin sites for the purposes of'storm water mitigation for development of the , } -College Master Plan. As directed by the Commission,the Town ofAndover will receive the G ancHlawry benefit iit f reduced paak stormwater runoff downstream of the detention basin sites. This is achieved through overcompensation and reduction of peak gates above and beyond what is required in the Massachusetts Department of Environmental Protection—Stormwater Management Guidelines under full implementation of the college Master Plan. .2 it is understood thai the timeframe for fdl build-out of the College Master Plan is approximately 30 years. .3 Construction of the two,detention asi sites will provide mitigation for increases in peak runoff rates associated with future campus development projects. The total increase in post- development peak rate of i-unoff with respect to existing conditions under the Mew c College Master Plan,with contingency allowances, is 62 cf , It is understood that this total peal,flow increase is mitigated through construction of the two basin sites,and that this value will serve as the credit upon which Merrimack College may compensate future developmet.}and.resultant increases in peak runoff rates. 51.4 After issuance of this Order, future Merrimack College developmentprojects within the watershed outlined in the Notice of Intent are subject to the following standards of review y the Comxm`ssion for the purpose of evaluating peak flow and storm water qUality impacts, a p 1 , x i e r F x iaclud ng any new Notice of Intent fled where proposed work is located wig a protected resource area or applicable buffer zone Wig the Town of Andover. J 40 'C:� 2,000 s�net impervious area increase—Activity does not need to be reported to the Commissi , except a summary an annual report to be fled wiffi the Conumssion at the end of each calendar year. 4 2, .5.0 sf e �m e o s area increase—Activity shall be reported to Commissiou staff with supporting documentation evaluating the estimated 'crease in Peak runoff rate, estimated reduction in peak flow credits to offset a peak runoff increase, and Best Management Practices(BN2"s)proposed to enhance water duality. These projects will be reviewed by Concession staff to verify compliance with.DEP--Stor. water.inageme t Guidelines(1995),and shall be considered acceptable by Commission staff if the Stonnwater Management Standards are met. s ors eater net-i r oes ZLea increase—Activity sal be reported to Commigsion staff'with supportffig do umentation va.uat' the estimated i erease in 9 peak runoff gate, estimated reduction in peak flow credits to offset a peak runoff . increase,�le t Management Practices (BW"s) ro proposed to auee water r quality, These projects will be reviewed by Commission staff to verify compliance with -Storrnwat r Management Guideline f 99 , and awl be considered insignificant by the Commission if the Stormwater Management Standards are met. Upon satisfactory proof of project ffisigmfflicance by the College,work may proceed with no fartdier review by the Commission. The Commission reserves the fight to require an Amended Order of Conditions for projects involving ,00 sf or greater f net impervious area mere e,m the event the project has an is npact to a resource area + under the Commission's legal jun"sdiction. For proj e s ire xin Plwing Board review and approval,the Conservation Commission may defer review oft the project until Planning Board action is taken. For or projects proposed wiflAn the'down of North Andover,technical preview of the submitted materials will be completed by an outside consultant as desi gated by the North Andover P1 Board and as outlined in the Site Plan Review Ping r u� emc is of the North Andover Zoning By-law. The College stall be responsible for submitting a letter to the,Co ssion at the end of each calendar year to summaripe projects completed during that year and a statement that the College has implemented all aspects of an Operation and Maintenance Plan, Remaining peals flow credits will be tracked informally ally by the Commission offices and formally documented in an Amended Order of Conditions under one of the following n scenario's,whichever occurs first. I. When a Notice of Intent is made for an amended Order of Conditions for a project, t which occurs within the jurisdiction of the Andover Conservation Cora=ss o .. } x 2. When the College applies for an extension of the existing Order of Conditions at five- year-intervals. Requests for an Amended Order of Conditions shall be in writing and extensions will be granted at five-year intervals to six times,at the Applicant's request. Upon completion of each authorized phase of.construction,the College shall have their engmeermg consultant evaluate the effectiveness and function of-the drainage improvements. The engineering consultant shall prepare and submit a report to the Con=* slon together with any recommendations for improvement or modifications o the drainage systemlo maintain the system's performance. The College shall be responsible t lenient all aspects of the Operation and Maintenance Plan for the Master Stonnwater Management Flan,including all + Maintenance measures on the detention pond,pang lot'sweeping, a ►d catch baste. maintenance. Men-finack College is responsible for the construction,maintenance,and mox itoring of the detention basin sites so that the optimal per'once of the bas'%ns is maintained, h Merrimack College has the right to modify,the detention asins and associated drainage structures for the purposes o increasing efficiency and/or merge the basin sites with future development projects. Detention basin modification is subject to review and approval of the Commission: } } _- G—WATER QUALITY. The Conservation Commission ids that In order to protect the interests of the Massachusetts wetland's Protection Act the Applicant shall be responsible to incorporate Best Management Practices for stonnwater enhancement quality on a project by project basis throughout the implementation of the Master Stormwater Management Plan. - 4 6. WORK AUTHORED DER TIES ORDEK Only work explicitly described in the above-referenced plans and Notice of Intent is authorized under this Order of Conditions. . STORMWATER MAN .G MENT# The Applicant or his successors ift interest shall be responsible in perpetuityto maintain all drainage and storm water management features-, F -mcludi g stormwater best management ex t practices(BWs)in good working order. The Y Conservation Conmiission reseves the right to enter upon the property and mare independent exammation of these BMP xa easures,.and to require the Applicant or his succes oars xn interest to perform such maintenance as is needed in its judgment. The:Conservation Commission shall provide prior notice to the property owner of its intent to perform such inspection not less than forty-eight hours prior to such M' Spection. This condition shall remain in effect perpetuity and shall survive the issuance of a Certificate of Compliance, . CERTIFICATE C N2 L�NCEt Not more than thirty dogs following completion of the project,the applicant shall submit with their re nest for a Cortificate of Conn Hance as affidavit r� prepared by a professional engineer or land surveyor registered the Commonwealth of x Massachusetts, stating that the site has been developed in accordance with the requirements irements o x t' k fts Order of Conditions, based upon are on-site inspection and the referenced site plan. Such request shall be accompanied by an as-built drams ,prepared by a Professional hand Surveyor or Professional Engineer, registered in the Conunonwealth of Massachusetts,and depicting the ffmal and actual condition of all areas within' the,jurisdiction of the Massachusetts Wetlands Protection Act* z i . INSTALLATION TION EROSION CONTROL. Prior to con nenceme t of work the applicant shall retain the services of the design professional or a Professional Land Surveyor to she out the location of the proposed sediment controls. The applicant shall then install the sediment controls i accordance with the above-referenced plans. } A written re nest for inspection of the erosion control shall be-submitted to the Conservation Commission., and a satisfacto inspection er onned before a land-di thin ac i n a commence. Other sediment controls may be reed by the Conservation Co ssion or' its F agents as field conditions warrant. The siltation control device shall be the Lit of Construction beyond which no each-disturbing activity shall occur or heavy equipment shall be allowed., All siltation and erosion controls shall b ,2 in a state of good repair. The siltation control devices shall not be removed until the commission'or its agent has reviewed and found satisfactory the stabilization of the disturbed area. 10,EXCAVATION DEWATERING. In the event that excavation dewatering is required wither any area subject to jurisdiction of the wetlands Protection Act the applicant shall notify .v. r. the Conservation Conumssion in advance of such word, and shall be responsible to ensure that such water is free of suspended solids before being discharged into either a wetland or into any storm water drAffiage system. This condition applies to all form of dewatering,including 4 ping and trenching. 11, NOTIFICATION COMMENCEMENT OF WORK. The applicant shall notify the Conservation Commission,in writing,48 hags before any activity oom a►.ences on the project site and shall a6isc the Conservation Commission ofthe name(s)and telephone numbers of the persons 'res'ponsiblc on site for compliance with this Order. This list shall be resubmitted if any*changes are made to it. y The developer or contraotor responsible for the projects completion shall,be notified of,and understand,the requirements of this Order of Conditions. The developer and/or'cunt ractor shall acknowledge receipt of the Order of Conditions by sn udtting a letter to that effect to the Conservation Cori scion. A copy of this Order,as well as copies of the above-mentioned documents,plans, and reports shall be on-site while activities regulated by this Order are being performed, `Ms Order of Conditions shall be made part of all construction documents for this prof eet. All contractors wort ng at the site shall be made aware of the provisions contained wit n this Order of Conditions and shall adhere to all the Special Conditions contained therein. The applicant, or his designee, shall,at all tomes,have a copy of the final order of Conditions at the site.and shall monitor compliance with the provisions of this Order, ` x x a 4 .s �. CONSTRUCTION R VEEW BY DESIGN EN MER REPORTS. The applicant shall be responsible to secure the services ofthe design professional or sn" nilarly credentialed professional on an on-going basis throughout all phases of the project that acre wtin the jurisdiction of this Order of Conditions. Inspections shall take place dig once every calendar days and witn 24 hours of the end of a 2 year storm event or greater(i.e.,3,2 inches of rainfall within a twenty-four hoar period),throughout the duration of the prof t, This period _ shall begin when siltation controls are installed, and shall end with.the issuance of a.Certificate of Compliance. The weeld logs/reports shall be submitted n a monthly basis to the * IP Conservation Conunisslon and sal state whether-such work is in his or her opuuon in compliance with the Order of Conditions. The Cons xv tlon Connaission reserves the right to v require submission of such reports on a more frequent interval. The applicani or his authofri ed representative.must prospectively request approval fox temporary cessation of reports in writing. Failure to-su it satisfactory reports shall be deemed,sufficient cause for revocation of this permit without further review. 13, GRADING AND STABILIZATION. Grading shall conform to theplans and data referenced above. In all ewes final grades shall have a mum of two inches of topsoil (measured in place) over all disturbed areas. In all cases exposed sail areas shall b stabilized with vegetation,e.g.,grass or some fornn of ground roger plant. In;no case shaU good chips, mulch,or filar covering he acceptable on sloping ground,gin l ou of vegetation. k •{r-`. 114. STOCKPILING. Staked hay bales to prevent sediment from space Doff from entering 4 _r the wetland must surround all debris, fill and excavated material stockpiles within.1 o feet of a A wetland area. 15. FONT OL OF CONSTRUCTION DEBRIS. No construction debris (paper,wood,-metal, concrete, etc.)may be allowed to enter the wetland resource areas at any time. windblown material shall be promptly removed from wetland resource areas. R 16. DAMAGE TO RESOURCE AREAS, Any damage caused`as a direct result of this} ro,e t to any wetland resource areas, beyond that authorized by the order,is the resp nsib lit of the applicant to repair,restore or replace. Sedimentation or erosion into these areas shall be considered damage to wetland resovxce areas. The Conservation Conmiission shall be promptly noted of any damage to wetland xesource areas. Following notification.,the applicant must submit a plan for abatement of the problem and restoration. The Conservation Con ssion prior to implementation must approve this plan. 17. SURPLUS.EARTH MATERIALS, It shall he the responsibility of the Applicant to ensure { that any and all surplus materials that are noi needed for use on the project are lawfully disposed of outside,any urea subject to protection under M.0 .c 13 1, s. 40,unless such disposal area and activity are regulated under either a valid Order of Conditions or Detennination of Applicability# t t t• x ' f R f x Massachusetts Department of Enviro'nmental Protectlon DEP File Number: Bureau of Resource Protection -Wetlands -0 ' 50 WPA 5 Order .of Conditions ro idedby DEP Massachusefts Wetlands Protecflon Act M.G.L. c. 131, §40 ' B. Findings (coat.) Additional conditions relating to municipal ordinance or bylaw:, { 1 This Order Is a lid for three years,unless otherwise specified as a special condition pursuant to General Condi on # ,from the dame of issuance. October 51 204 48T 004(expiration date) • -ect fiyp.�year Dala f ' This Order must be signed by a majority of the Conservation Commission.The Order must be mailed by certified mail(return receipt requested)or hand delivered to the applicant,A copy also must he mailed or hand delivered at the same time to the appropriate Department rtment of Environmental Protectioil Regional -- Office(see Appendix and the property owner(If different from applicant). 44 y n 17 ' Of .duly 2001 k Day Month and'Year .....� before me personally.appeared P h* lip to me known n to be the person described in and who executed the foregoing instrument and acknowledged that he/she executed the same as histher free act and deed. Orly 22,2005 r Public ley Camrr�Fssion Expires This der i issued to the applicant as follows; { by hand delivery on Z by certified mail,return requested,receipt on F 2001 Datet WPA Fom 5 Ft y.0=0 i r n � 4 Massachusetts Department of Environmental Protection D P iN Number: Bureau of Resource Protection --Wetlands 0-0 6 WPA Form 5 opm Order.of Conditio' ns Provided by D P . Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 • ______— �YiYlililWiiY.IW!•• •1 1•q0•;'!IA! �. Y w��P��w.+!l�Y�Iw.fVr■4IMw�1�"�f Ce Appeals The applicant, tho owner, any person aggrieved by this Order, any owner of lard abutting the land subject to this Order, or any ten residents of the icity or town in which such land is located,are hereby notified of their right to request the appropriate DEP Regional Office to issue a Superseding Order of Conditions. The request must be made by certified r ii or hand dei!very to the Department, with the appropriate filing fee and completed Appendix E: Request of Departmental Action Fee Transmittal Form, as provided in 310 CMR 10. 7 within ten business days from the date of issuance of this Order.A copy ofthe request shall at the same time be seat by certified rail or hand delivery t -t e Conservaflon Commission and t the applicant, if he/she is not the appellant. n The request shall state clearly and concisely the objections to the Order which is being appealed and hove the Order does not contribute to the pr to tl n of the interests identified in the Massachusetts Wetlands Y x Protection Act, M.G.L.c. 131,§ )and is inconsistent with the wetlands regulations(310 CMR 10.00). To the extent that the Order is based.on a municipal ordinance or bylaw,and not on the Massachusetts Wetlands Protection Act or regulations,the Department has no appellate jurisdicfion. i D. n ` i r Y Recordinginformatio'n This Order of Conditions must be recorded in the Registry of Dieeds or th6 Land Court for the district in _ which the land is located,within the chafn of title of the affected property. In the case of recorded land, the Final Order small also be noted in the'Registry's Grantor inde sunder the name of the owner f the rand ` subject to the Order. In the case of registered land, this Order shall also be noted on the Land Court Certificate of Title of the o n r of the land subject to the Order"of Conditions.The recording information n Page 7 of Form 5 shall be submitted to the Conservation Commission listed below. } Andover , Conservation Commission J £ i i 1A Form 5 Pap ig Of 7 e 02MO Massachusetts D r�tm n nvironr a tal Pr o i r� DEP Fite umber: Bureau of Resource Protection -Wetlands - 90-0750 t PA Form 5 ow, Order of Conditions Provided by DEP Massachusefts Wetlands Protection Act M.G.L. c. 131, §40 D. RecordingInfo m ion ont.J Detach on dotted liege,have stamped by the Registry of Deeds and submit to the Conservation Commission, * fsa: �fr �: tir�r� � �rrsfw*srrtir�rrr �r rr �r :rir�� .rf��tf�r : r� r To: Andover Conservotion Commission io Please a advised that the Order of Conditions for the Project at Merrimack College(315-Turn i e St, &ElmSt. -0 o Project Location DEP File Nufter,, Has been recorded at the Registry of deeds of. " County Book Page for: Property 0 wn er a ' and has been noted in the chain of title of the affected property in: Book Page In accordance with the Order of Conditions issued on.- Date If recorded lard,the instrument number identifying this transaction is: Instrument Number F If registered land,the document number identifying this transaction is: Document Number } x 1 f nature of Applicant y a 1 WP Pon DEIPARTMENT OF COMMUNITY DEVELOPMENT AND PLANNING ANDOVER TOWN OFFICES Tracey J.Gangi.,P Sasaki Assoc.,Inc. 4 Pleasant Street Watertown,MA 02472 �x 4,21,► . 1 w. r 5 y� to , to } .brim heir I[:,e rt G��rde��r o''If III uuuuuuu uuuumuuuu luumu uuuuu°uuuu uuuuuu� 0901111111111,11,111,1,01111111711150 muuul uuu uumu I� uuuuu uuuuupl ui IVI. IIOim 111111 puuonlpu ""'Its uu uuum u mu mmuuuumm G-3 Appendix G:Approved Stormwater Management Plan Documents AMENDED ORDER OF CONDITIONS Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection - Wetlands W PA F o�,,,� � � ��„���„ of � MassDEP File# ondit ons th 000-750 5 Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE X[V ANDOVER WETLANDS PROTECTION BY-LAW eDEP Transaction# / - ii Andover d r 41r 1�� � � City/Town A. General Information _ Important: Andover When filling 1. From. Conservation Commission out forms on the 2. This issuance is for computer, (check one): a.E]Order of Conditions b. ®Amended Order of Conditions use only the tab key to 3. To: Applicant: move your cursor-do not use the a. First Name b. Last Name return key. Merrimack COfle e rsb c.organization 315 Turnpike Street d.Mailing Address North Andover MA 01845 e. City/Town f.State g.Zip Code 4. Property Owner(if different from applicant): a. First Name b. Last Name c.organization d.Mailing Address e. City/Town f.State g.Zip Code 5. Project Location: 0 Elm Streetl315 Turnpike Street Andover/North Andover a. Street Address b.City/Town 2 50 c.Assessors Map/Plat Number d. Parcel/Lot Number Latitude and Longitude, if known: d m s d m s d. Latitude e. Longitude wpaform5.doc• rev.03/2/2010 Page 1 of 12 Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection - Wetlands MassDEP File# WPA Form 5 - Order of Conditions 1h 090-750 5 Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE XIV, ANDOVER WETLANDS PROTECTION BY-LAW eDEP Transaction# Andover City/Town This document consists of pages. A. General Information (cont.) 6. Property recorded at the Registry of Deeds for(attach additional information if more than one parcel): Essex North District a. County b.Certificate Number(if registered land) 30 329 c. Book d.Page June 5, 2018 '=" �• ' 7. Dates: a. Date Request for Amendm ent ment b. Date blic H acing Closed c. Date oOssuance s. Final Approved Plans and other Documents (attach additional plan or document references as needed): Carn us Parking Improvements, Merrimack College a. Plan Title VHB Jeffrey Koetteritz, P.E. b. Prepared By c.Signed and stamped by 015/1 8 As noted d. Final Revision Date e.Scale f.Additional Plan or Document Title g. Date B. Findings 1. Findings pursuant to the Massachusetts Wetlands Protection Act: Following the review of the above-referenced Notice of Intent and based on the information provided in this application and presented at the public hearing, this Commission finds that the areas in which work is proposed is significant to the following interests of the Wetlands Protection Act(the Act). Check all that apply: a. El Public Water Supply b. E:1 Land Containing Shellfish c. Z Prevention of Pollution d. ® Private Water Supply e. EJ Fisheries f. Z Protection of p y Wildlife Habitat g. ® Groundwater Supply h. ® Storm Damage Prevention i. N Flood Control 2. This Commission hereby finds the project, as proposed, is: (check one of the following boxes) Approved subject to: a. N the following conditions which are necessary in accordance with the performance standards set forth in the wetlands regulations. This Commission orders that all work shall be performed in accordance with the Notice of Intent referenced above, the following General Conditions, and any other special conditions attached to this order. To the extent that the following conditions modify or differ from the plans, specifications, or other proposals submitted with the Notice of Intent, these conditions shall control. wpaform5.doc• rev.03/2/201 0 Page 2vf12 Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection -Wetlands MassDEP File# WPA Form 5 - Order of Conditions 090-750 5th Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE XIV,ANDOVER WETLANDS PROTECTION BY-LAW eDEP Transaction# Andover City/Town B. Findings (cant.) Denied because: b. [:] the proposed work cannot be conditioned to meet the performance standards set forth in the wetland regulations. Therefore, work on this project may not go forward unless and until a new Notice of Intent is submitted which provides measures which are adequate to protect the interests of the Act, and a final order of Conditions is issued. A description of the performance standards which the proposed work cannot meet is attached to this Order. c. El the information submitted by the applicant is not sufficient to describe the site, the work, or the effect of the work on the interests identified in the Wetlands Protection Act. Therefore, work on this project may not go forward unless and until a revised Notice of Intent is submitted which provides sufficient information and includes measures which are adequate to protect the Act's interests, and a final order of Conditions is issued. A description of the specific information which is lacking and why it is necessary is attached to this order as per 310 CMR 10.05(6)(c). 3. ❑ Buffer Zone Impacts: Shortest distance between limit of project a. linear feet disturbance and the wetland resource area specified in 310 CMR 10.02(1)(a) Inland Resource Area Impacts: Check all that apply below. (For Approvals only) Resource Area Proposed Permitted Proposed Permitted Alteration Alteration Replacement Replacement 4. ❑ Bank a. linear feet b. linear feet c. linear feet d. linear feet 5. ❑ Bordering Vegetated Wetland a.square feet b.square feet c.square feet d.square feet 6. El Land Under Waterbodies and a.square feet b.square feet c.square feet d.square feet Waterways e.cly dredged f.cly dredged 7. ❑ Bordering Land Subject to Flooding a.square feet b.square feet c.square feet d.square feet Cubic Feet Flood Storage e.cubic feet f.cubic feet g.cubic feet h.cubic feet 8. ❑ Isolated Land Subject to Flooding a.square feet b.square feet Cubic Feet Flood Storage c.cubic feet d.cubic feet e.cubic feet f.cubic feet 9. ❑ Riverfront Area a tntni cn facet b.total sq.feet Sq ft within 100 ft r ctti Tara fawt d.square feet in cris rarer faint f.square feet wpaform5.doc• rev.❑3121201❑ Page 3 of 12 Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection - Wetlands MassDEP File# r� WPA Form 5 - Order of Conditions 090-7 5o 5th Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE XIV,ANDOVER WETLANDS PROTECTION BYLAW eDEP Transaction# Andover C ity/Town Sq ft between 100- 200 ft ri em inrim faaf h.square feet minro .square feet B. Findings (cont.) Coastal Resource Area Impacts: Check all that apply below. (For Approvals only) Proposed Permitted Proposed Permitted Alteration Alteration Replacement Replacement l o. El Designated Port Areas Indicate size under Land Under the ocean, below 11. El Land Under the Ocean a.square feet b.square feet c.c/y dredged d.c/y dredged 12. ❑ Barrier Beaches Indicate size under Coastal Beaches and/or Coastal Dunes below 13. ❑ Coastal Beaches cu yd cu yd a.square feet b.square feet q q c. nourishment d. nourishment 14. ❑ Coastal Dunes cu yd cu yd a.square feet b.square feet q q c.nourishment d. nourishment 15. ❑ Coastal Banks a. linear feet b i.linear feet 16. ❑ Rocky Intertidal Shores a.square feet b.square feet 17. ❑ Salt Marshes a.square feet b.square feet c.q q square feet d.square feet 18. ❑ Land Under Salt Ponds a.square feet b.square feet c.c/y dredged d.c/y dredged i g. ❑ Land Containing Shellfish a.square feet b.square feet c.square feet d.square feet 20. El Fish Runs Indicate size under Coastal Banks, Inland Bank, Land Under the ocean, and/or inland Land Under Waterbodies and Waterways, above a.c/y dredged b.c/y dredged 21. ❑ Land Subject to Coastal Storm a.square feet b.square feet Flowage wpaform5.doc• rev.03/2/2010 Page 4 of 12 Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection -Wetlands MassDEP File# WPA Form 5 . Order of Conditions fh 09D-750 5 Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE XIV,ANDOVER WETLANDS PROTECTION BY-LAW eDEP Transaction# Andover C ity/Town B. Findings (cont.) #22.If the 22 Restoration/En hancement : project is for the purpose of restoring or a.square feet of BVW enhancing a q b.square feet of salt marsh wetland resource area 23• ❑ Stream Grossing(s): in addition to the square footage that a.number of new stream crossings b. number of replacement stream crossings has been C. General Conditions Under Massachusetts Wetlands Protection Act entered in Section B.5.c tgVVV3 or The following Conditions are only applicable to Approved projects. B.1 7.c(Salt Pp Marsh)above, Failure to comply with all conditions stated herein, and with all related statutes and other please enter regulatory measures shall be deemed cause to r the additional 9 y evoke or modify this Order. amount here. 2. The Order does not grant any property rights or any exclusive privileges; it does not authorize any injury to private property or invasion of private rights. 3. This Order does not relieve the permittee or any other person of the necessity of complying with all other applicable federal, state, or local statutes, ordinances, bylaws, or regulations. 4. The work authorized hereunder shall be completed within three years from the date of this Order unless either of the following apply: a. the work is a maintenance dredging project as provided for in the Act; or b. the time for completion has been extended to a specified date more than three years, but less than five years, from the date of issuance. If this Order is intended to be valid for more than three years, the extension date and the special circumstances warranting the extended time period are set forth as a special condition in this Order. 5. This Order may be extended by the issuing authority for one or more periods of up to three years each upon application to the issuing authority at least 30 days prior to the expiration date of the Order. 6. If this Order constitutes an Amended Order of Conditions, this Amended Order of Conditions does not extend the issuance date of the original Final Order of Conditions and the Order will expire on unless extended in writing by the Department. 7. Any fill used in connection with this project shall be clean fill. Any fill shall contain no trash, refuse, rubbish, or debris, including but not limited to lumber, bricks, plaster, wire, lath, paper, cardboard, pipe, tires, ashes, refrigerators, motor vehicles, or parts of any of the foregoing. S. This Order is not final until all administrative appeal periods from this Order have elapsed, or if such an appeal has been taken, until all proceedings before the Department have been completed. wpaform5.doc• rev.03/2/2010 Page 5 of 12 Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection - Wetlands MassDEP File# f WPA Form a — Order of Conditions 090-7505t" Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE XIV,ANDOVER WETLANDS PROTECTION BY-LAW eDEP Transaction# Andover City/Town C. General conditions Under Massachusetts Wetlands Protection Act (cont.) 9. No work shall be undertaken until the order has become final and then has been recorded in the Registry of Deeds or the Land Court for the district in which the land is located, within the chain of title of the affected property. In the case of recorded land, the Final order shall also be noted in the Registry's Grantor Index under the name of the owner of the land upon which the proposed work is to be done. In the case of the registered land, the Final order shall also be noted on the Land court certificate of Title of the owner of the land upon which the proposed work is done. The recording information shall be submitted to the Conservation commission on the form at the end of this order, which form must be stamped by the Registry of Deeds, prior to the commencement of work. 10. A sign shall be displayed at the site not less then two square feet or more than three square feet in size bearing the words, "Massachusetts Department of Environmental Protection" [or, "MassDEP"] "File Number 090-750 it Amended 11. Where the Department of Environmental Protection is requested to issue a Superseding Order, the conservation Commission shall be a party to all agency proceedings and hearings before MassDEP. 12. Upon completion of the work described herein, the applicant shall submit a Request for Certificate of compliance (WPA Form 8A) to the conservation Commission. 13. The work shall conform to the plans and special conditions referenced in this order. 14. Any change to the plans identified in condition#1 3 above shall require the applicant to inquire of the Conservation Commission in writing whether the change is significant enough to require the filing of a new Notice of Intent. 15. The Agent or members of the Conservation commission and the Department of Environmental Protection shall have the right to enter and inspect the area subject to this Order at reasonable hours to evaluate compliance with the conditions stated in this Order, and may require the submittal of any data deemed necessary by the conservation Commission or Department for that evaluation. 16, This order of conditions shall apply to any successor in interest or successor in control of the property subject to this order and to any contractor or other person performing work conditioned by this order. 17. Prior to the start of work, and if the project involves work adjacent to a Bordering Vegetated Wetland, the boundary of the wetland in the vicinity of the proposed work area shall be marked by wooden stakes or flagging. once in place, the wetland boundary markers shall be maintained until a Certificate of compliance has been issued by the conservation wpaform5.doc• rev_03I212010 Page 6 of 12 Provided by MassDEP: Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands WPA Form 5 — order of Conditions MassDEP File#99a-75o 5th Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE XIV,ANDOVER WETLANDS PROTECTION BY-LAW eDEP Transaction# Andover City/Town Commission. C. General Conditions Under Massachusetts Wetlands Protection Act (cant.) 18. All sedimentation barriers shall be maintained in good repair until all disturbed areas have been fully stabilized with vegetation or other means. At no time shall sediments be deposited in a wetland or water body. During construction, the applicant or his/her designee shall inspect the erosion controls on a daily basis and shall remove accumulated sediments as needed. The applicant shall immediately control any erosion problems that occur at the site and shall also immediately notify the Conservation Commission, which reserves the right to require additional erosion and/or damage prevention controls it may deem necessary. Sedimentation barriers shall serve as the limit of work unless another limit of work line has been approved by this order. NOTICE OF STORMWATER CONTROL AND MAINTENANCE REQUIREMENTS 19. The work associated with this order(the "Project") is (i)® is not(2)E subject to the Massachusetts Stormwater Standards. If the work is subject to the Stormwater Standards,then the project is subject to the following conditions: a) All work, including site preparation, land disturbance, construction and redevelopment, shall be implemented in accordance with the construction period pollution prevention and erosion and sedimentation control plan and, if applicable, the Stormwater Pollution Prevention Plan required by the National Pollution Discharge Elimination System Construction General Permit as required by Stormwater Condition 8. Construction period erosion, sedimentation and pollution control measures and best management practices (BMPs) shall remain in place until the site is fully stabilized. b) No stormwater runoff may be discharged to the post-construction stormwater BMPs unless and until a Registered Professional Engineer provides a Certification that: i. all construction period BMPs have been removed or will be removed by a date certain specified in the Certification. For any construction period BMPs intended to be converted to post construction operation for stormwater attenuation, recharge, and/or treatment, the conversion is allowed by the MassDEP Stormwater Handbook BMP specifications and that the BMP has been properly cleaned or prepared for post construction operation, including removal of all construction period sediment trapped in inlet and outlet control structures; ii. as-built final construction BMP plans are included, signed and stamped by a Registered Professional Engineer, certifying the site is fully stabilized; iii. any illicit discharges to the stormwater management system have been removed, as per the requirements of Stormwater Standard 19; iv. all post-construction stormwater BMPs are installed in accordance with the plans (including all planting plans) approved by the issuing authority, and have been inspected to ensure that they are not damaged and that they are in proper working condition; v. any vegetation associated with post-construction BMPs is suitably established to withstand erosion. wpaform5.doc• rev.03/2/2010 Page 7 of 12 Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection - Wetlands , WPA Form 5 - Order of Conditions MassDEP File# 090-750 5th Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE XIV,ANDOVER WETLANDS PROTECTION BY-LAW eDEP Transaction# Andover City/Town C. General Conditions Under Massachusetts Wetlands Protection Act (cont.) c) The landowner is responsible for BMP maintenance until the issuing authority is notified that another party has legally assumed responsibility for BMP maintenance. Prior to requesting a Certificate of Compliance, or Partial Certificate of Compliance, the responsible party (defined in General Condition 18(e)} shall execute and submit to the issuing authority an operation and Maintenance Compliance Statement("O&M Statement) for the Stormwater BMPs identifying the party responsible for implementing the stormwater BMP Operation and Maintenance Plan ("O&M Plan") and certifying the following: i.) the O&M Plan is complete and will be implemented upon receipt of the Certificate of Compliance, and ii.) the future responsible parties shall be notified in writing of their ongoing legal responsibility to operate and maintain the stormwater management BMPs and implement the Stormwater Pollution Prevention Plan. d) Post-construction pollution prevention and source control shall be implemented in accordance with the long-term pollution prevention plan section of the approved Stormwater Report and, if applicable, the Stormwater Pollution Prevention Plan required by the National Pollution Discharge Elimination System Multi-Sector General Permit. e) Unless and until another party accepts responsibility, the landowner, or owner of any drainage easement, assumes responsibility for maintaining each BMP. To overcome this presumption, the landowner of the property must submit to the issuing authority a legally binding agreement of record, acceptable to the issuing authority, evidencing that another entity has accepted responsibility for maintaining the BMP, and that the proposed responsible party shall be treated as a permittee for purposes of implementing the requirements of Conditions 18(f) through 18(k)with respect to that BMP. Any failure of the proposed responsible party to implement the requirements of Conditions 18(f) through 18(k)with respect to that BMP shall be a violation of the order of Conditions or Certificate of Compliance. In the case of stormwater BMPs that are serving more than one lot, the legally binding agreement shall also identify the lots that will be serviced by the stormwater BMPs. A plan and easement deed that'grants the responsible party access to perform the required operation and maintenance must be submitted along with the legally binding agreement. f) The responsible party shall operate and maintain all stormwater BMPs in accordance with the design plans, the 0&M Plan, and the requirements of the Massachusetts Stormwater Handbook. wpaforrn5.dvc• rev.03/2/2010 Page 8 of 12 Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection -Wetlands WPA Form order ofConditionsMassDEP File# 090.7505th Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE XIV,ANDOVER WETLANDS PROTECTION BY-LAW eDEP Transaction# Andover C ity/Town C. General Conditions Under Massachusetts Wetlands Protection Act (cunt.) g) The responsible party shall: I Maintain an operation and maintenance log for the last three (3) consecutive calendar years of inspections, repairs, maintenance and/or replacement of the stormwater management system or any part thereof, and disposal (for disposal the log shall indicate the type of material and the disposal location); 2. Make the maintenance log available to MassDEP and the Conservation Commission ("Commission") upon request; and 3. Allow members and agents of the MassDEP and the Commission to enter and inspect the site to evaluate and ensure that the responsible party is in compliance with the requirements for each BMP established in the O&M Plan approved by the issuing authority. h) All sediment or other contaminants removed from stormwater BMPs shall be disposed of in accordance with all applicable federal, state, and local laws and regulations. i) Illicit discharges to the stormwater management system as defined in 310 CMR 10.04 are prohibited. j) The stormwater management system approved in the order of Conditions shall not be changed without the prior written approval of the issuing authority. k) Areas designated as qualifying pervious areas for the purpose of the Low Impact Site Design Credit(as defined in the MassDEP Stormwater Handbook, Volume 3, Chapter 1, Low Impact Development Site Design Credits) shall not be altered without the prior written approval of the issuing authority. 1) Access for maintenance, repair, and/or replacement of BMPs shall not be withheld. Any fencing constructed around stormwater BMPs shall include access gates and shall be at least six inches above grade to allow for wildlife passage. Special Conditions (if you need more space for additional conditions, please attach a text document): wpaform5.doc• rev.03/2/201 a Page 9 of 12 Massachusetts Department of Environmental Protection Provided by»assDEP: Bureau of Resource Protection - V�/���� _ WPA Form �� __ Order ^�� Conditions wwnou�r�mo� `~ ~~" 090-7505m Massachusetts Wetlands Protection Act KG.Lo. 131 1 §40 Amendment AND ARTICLE XiV. ANDOVER WETLANDS PROTECTION BY-LAW ' --- .. _±Andover_____ D. Find ings Un der M u 41 nicipa-9 1 All Wetla-n J ds Byl a%worO rdinan L ce 1 Is a municipal wetlands bylaw orordinmnre applicable? Z Yes 0 No 2. The A __________ hereby �nds (check one that appUem)/ �"��wvmm�ommmaum m. that the proposed work cannot be conditioned to meet the standards set forth /na municipal ordinance or bylaw, apar,UlcaUy/ Article XIV Wetlands Prot8cfion .Bv-Low ___________________ By-Law .. __.._,_ _~.~,~_,. ./�� o. 0 I'tgmm Therefore, work on this project may not gn forward unless and until m revised NoUmmof Intent /msubmitted which provides oneaaurem which anmadequate torneetthese standards, and a final Order of Conditions imissued. 0. [l that the following additional conditions are necessary \o comply with amunicipal onJ|nmnce or bylaw, -___-'__- 1 mmnm�m|��in�nmyu,�y�� ----'--------------- --���on---'' o. The Commn(ms|on orders that all work shall be perfonned /n accordance with the following conditions and with the Notice ofIntent referenced above,. To the extent that the following ic,ondiflons modify or differ from the plans, specifications, or other proposals submitted with the Notice oy Intent, the conditionm shall oontrni The spacial conditims relating to municipal ordinance or bylaw are aS follows (it you need more mpoQe for additional conditions, attach a text docurnmnt)j ` .................................... .....__-__- .................. ___---___-______-___-__-__ See putmo*md sheet for Special Conmuonn and Findings, _......._ .................__--_-__-_......... _............ ............... .............. ......... ............. ... _ ...... ........... _--........................ _-_--_ °p.m"�*=' °° ommm,u Pap`oof`2 Merrimack College Amended Order of Conditions Campus Parking Improvements DEP FIDE NO. 090-0750 5"1 Amendment SPECIAL CONDITIONS (Note previous conditions apply) a) RELIANCE UPON PEER REVIEW. The Conservation Commission is in partial reliance upon a peer review of the filing and additional submittals (Request for Amended Order of Conditions dated July 3 by VHB) completed by Janet Bernardo of Horsley Witten Group. The documentation for this review is comprised of a letter report dated July 2 and July 9, 2017,which states "the proposed Stormwater design is in compliancewith the original Order of Conditions dated July 17, 2001 and the Amended order issued August 23, 2016 as well as the WPA and Stormwater handbook. Please note; The approved work(when completed)will--in reference to the applicant's July 2018 Credit Summary - under this Amendment W will have the remaining peak flow credit value of 14.63 cfs. b) Conservation Commission and the Cominission's Site Monitor, in writing, 48 hours before any activity commences on the project site and shall advise the Conservation Commission and the Commission's Site Monitor of the name(s) and telephone number(s) of the person(s) responsible on site for compliance with this order. This list shall be resubmitted if any changes are made to it. The developer or contractor responsible for the proj ect's completion shall be notified of, and understand, the requirements of this Order of Conditions. The developer•and/or contractor shall acknowledge receipt of the Order of Conditions by submitting a letter to that effect to the Conservation Commission. A copy of this Order, as well as copies of the above-mentioned documents, plans, and reports shall be on-site while activities regulated by this Order are being performed. This Order of Conditions shall be made part of all construction documents for this project. All contractors working at the site shall be made aware of the provisions contained within this Order of Conditions and shall adhere to all the Special Conditions contained herein. The applicant, or his designee, shall, at all times, have a copy of the Final Order of Conditions at the site and shall monitor compliance with the provisions of this Order. c) CONSTRUCTION OVERVIEW BY DESIGN ENGINEER/REPORTS. In accordance with Massachusetts General Laws Chapter 44, §53G, the Conservation Commission requires that the applicant provide funds prior to commencement of work to the Commission for the reasonable fees of a consultant with professional credentials to be selected by the Commission to review and/or approve the inspection of work thereunder. Such fees shall be an estimate of inspections which shall take place during once every 7 calendar days and i l in 24 hours of theend I a storm event having '2 inch o f rafli("Afl Or greater witb ll a, t CrIt -.[bUr 110L11-POF1od. thro u ghout the. duratian of the pmjek tr This period s h a I I begin when i t itIO11 COT11'rols are .installed, and sbGall cnd with issuance f a Certificate oi Con.1plianc . Since the fees am an timat , -.,Wditional Fees may requhv I�cixdhig the t1ut#ution of the l*oje t and/or overpayment retur-ned to the ;ppficant ������ ��� issuanceof a Certificate of Co mp1161lice, Where subnusslon of a ceart flied foundation plan is otherwise required Under this 01'--der of Conditions fa copy of���id certi-ficd -tbundatlon plan. shall be attziched to the next mspcct.i n. report following installatIon.of th foun ation, ''Fhe weekly logs/ ports shall be su brn'I' � d on ����ombl usi to the �onservati n .���m.��ussi n and kliall state whether Stich work is in his or her op.i.n Ion in comp Iian °ith flee Order of Con ItIo s, The Conservation Coui-mission re er e8 right to require SUbmiss-oil �� ',tic� reports on a nior frequent i�t��+ c�1, Theon i+vafiou Commission also i- s i- s the right to authori a the, consultant to i-veduce the umbei- of AP weekly Inspecti ons Submitted on a monthly ba is at their- disereflon,. Ili e, al)pIicant m ust req ues,t approval for tempo rary ces-sa uon o f repolat iriting pro spect1ve y This request must have the, p�-����� ������t+ �x� ��f���� ��t �' �+ t�� '����� ���� i�t �iaINUI+c- 10 sub. lit, satisfactory re orts shall b deer ed ��1�:���.�i���.�: use for revocation of this I.,)er���it i� ���.�t f ii rt her review. Peal(Flow Credit Summary by Project Merrimack College Stormwater Master Plan DEP File No.090-0750 Campus Parking Improvements July 2018 The following summary table has been prepared to document the credits applied for associated projects from the Stormwater Master Plan banking system,initially established at a rate of 62.0 c.f.s under the Merrimack College,Master Drainage Study and Hydrologic Analysis,dated April 26, 1999 and approved under DEP File No.090-0750. Net Increase in 100-yr Remaining Peak Flow Pro ect Bate Peak Rate(cfs) Credit Sophomore Housing 2/2002 3.4 58.60 Lot D Parking Lot Extension 3/2003 11.5 47.10 Monican Boulevard Relocation 5/2004 -2.54 49.64 Game Field Renovations 3/2005 0.00 49.64 Elm Street Entrance 5/2006 -0.69 50.33 Volpe Center Expansion 10/2011 1.6 48.73 Student Residences Project 7/2012 4.4 44.33 -r', 4444 3940 North Campus Updated Phase 1 Residential,Academic Buildings A, 2/2017 25.8 18.53 B,C and Sakowich Expansion* Athletics District Improvements 3/2017 1.20 17.33 :.:.Cam usaParkln :Im ravements;,,,. , :�'1 _ x - ..:....:.., 'Peak Flow Credit deducted from 712014 and 812016 North Campus superseded by current updated model for North Campus Updated Phase 1 Residential Academic Buildings A,B,C and Sakowich Expansion,as noted above. I1vhblprojlWat-LD\11625.16 Merrimack Park inglreportalStormwater Repo&Appendix H-Approved Stormwater Management Doc uments\B3-Peak Flow Credit Summary by Project.docx Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection - Wetlands MassDEP File# r WPA Form 5 -- Order of Conditions 090-7505 th Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE XIV,ANDOVER WETLANDS PROTECTION BYLAW eDEP Transaction# Andover City/Town E. Signatures This order is valid for three years, unless otherwise specified as a special j m ey condition pursuant to General Conditions#4,from the date of issuance. 1. Date �J!su nce Please indicate the number of members who will sign this form. This Order must be signed by a majority of the Conservation Commission. 2. Number of Signers The order must be mailed by certified mail (return receipt requested)or hand delivered to the applicant.A copy also must be mailed or hand delivered at the same time to the appropriate Department of Environmental Protection Regional office, if not filing electronically, and the property owner, if different from applicant. Signatu es: P yy/I l, ff � 3; fF' b han deliver on E:1 by certified mail, return receipt � y y requested, on 1A Date Date F. Appeals The applicant, the owner, any person aggrieved by this order, any owner of land abutting the land subject to this order, or any ten residents of the city or town in which such land is located, are hereby notified of their right to request the appropriate MassDEP Regional Office to issue a Superseding order of Conditions. The request must be made by certified mail or hand delivery to the Department, with the appropriate filing fee and a completed Request of Departmental Action Fee Transmittal Form, as provided in 310 CMR 10.03(7)within ten business days from the date of issuance of this order. A copy of the request shall at the same time be sent by certified mail or hand delivery to the Conservation Commission and to the applicant, if he/she is not the appellant. Any appellants seeking to appeal the Department's Superseding order associated with this appeal will be required to demonstrate prior participation in the review of this project. Previous participation in the permit proceeding means the submission of written information to the Conservation Commission prior to the close of the public hearing, requesting a Superseding Order, or providing written information to the Department prior to issuance of a Superseding Order. The request shall state clearly and concisely the objections to the Order which is being appealed and how the order does not contribute to the protection of the interests identified in wpaform5_doc• rev.0312/2010 Page 11 of 12 Massachusetts Department of Environmental Protection Provided by MassDEP: Bureau of Resource Protection - Wetlands MassDEP File# WPA Form a — Order of Conditions th 090-750 5 Massachusetts Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE xIV,ANDOVER WETLANDS PROTECTION BY-LAW eDEP Transaction# Andover C i ty/Tow n the Massachusetts Wetlands Protection Act(M.G.L. c. 131, §40), and is inconsistent with the wetlands regulations (310 C M R 10.00). To the extent that the Order is based on a municipal Ordinance or bylaw, and not on the Massachusetts Wetlands Protection Act or regulations, the Department has no appellate jurisdiction. G. Recording Information Prior to commencement of work, this Carder of Conditions must be recorded in the Registry of Deeds or the Land Court for the district in which the land is located, within the chain of title of the affected property. In the case of recorded land, the Final Order shall also be noted in the Registry's Grantor Index under the name of the owner of the land subject to the Order. In the case of registered land, this Order shall also be noted on the Land Court Certificate of Title of the owner of the land subject to the Order of Conditions. The recording information on this page shall be submitted to the Conservation Commission listed below. Andover Conservation Commission Detach on dotted line, have stamped by the Registry of Deeds and submit to the Conservation Commission. --------------------------------------------------------------------------------------------------------------- To: Andover Conservation Commission Please be advised that the Order of Conditions for the Project at: 0 Elm Street, Andoverl31 5 Turnpike Street, 090-750 Amended North Andover MassDEP File Number Has been recorded at the Registry of Deeds of: Essex North District County Book Page for' Property Owner and has been noted in the chain of title of the affected property in: Book Page In accordance with the Order of Conditions issued on: Date If recorded land, the instrument number identifying this transaction is: Instrument Number If registered land, the document number identifying this transaction is: wpaform5.doc• rev.03/2/2010 Page 12 of 12 Massachusetts Department,of Environmental Protection Provided by MassD:EP- B,ureau of Resource Protection - Wetlands ® MassDEP File# WPA Form 5 — Order of Condit 090-75051h Massachusetts,Wetlands Protection Act M.G.L. c. 131, §40 Amendment AND ARTICLE,XIV,ANDOVER WETLANDS PROTECTION BY'-LAW eDEP Transaction# Andover City[Town Doc ent or Signatm A pli t wpaform5.doc rev.O3/2/201 0 Page 13 of 12 .brim heir I[:,e rt uuumll uumumuuun�I �IIIII. uuuu �� � I I I � I IlU�uullll� uum°11lumn� Im hiioivlul� II uuuumuum i IpW uuu umuu mmuuum� I VI IpW V uuuuuuuuu i II umIllVlll pu G-4 Appendix G:Approved Stormwater Management Plan Documents Peak Flow Credit Summary by Project Merrimack College Stormwater Management Plan DEP File No. 090-0750 Lecture Hall September 2024 The following summary table has been prepared to document the credits applied for associated projects from the Stormwater Master Plan banking system, initially established at a rate of 62.0 c.f.s under the Merrimack College, Master Drainage Study and Hydrologic Analysis, dated April 26, 1999 and approved under DEP File No. 090-0750. Net Increase in 100-yr Remaining Peak Flow Project Date Peak Rate (cfs) Credit Sophomore Housing 2/2002 3.4 58.60 Lot D Parking Lot Extension 3/2003 11.5 47.10 Monican Boulevard Relocation 5/2004 -2.54 49.64 Game Field Renovations 3/2005 0.00 49.64 Elm Street Entrance 5/2006 -0.69 50.33 Volpe Center Expansion 1012011 1.6 48.73 Student Residences Project 7/2012 4.4 44.33 Nert h Q;4mPi s. Deyele.Pmon+* 7 Ner h Q;;rvmPi is lAcademir* 8/204-6 0 North Campus Updated Phase 1 Residential,Academic Buildings A, 2/2017 25.8 18.53 B,C and Sakowich Expansion* Athletics District Improvements 3/2017 1.20 17.33 Campus Parking Improvements 7/2018 2.7 14.63 Lecture Hall 9/2024 0.0 14.63 *Peak Flow Credit deducted from 712074 and 812016 North Campus superseded by current updated model for North Campus Updated Phase 1 Residential,Academic Buildings A,B,C and Sakowich Expansion,as noted above. \\vhb.com\gbl\profAWat-LD\l 1625.37 Merrimack Lecture Hall\Reports\Stormwater\Appendices\Appendix G-Approved Stormwater Management Plan Documents\G3-Peak Flow Credit Summary by Project.docx