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Home My WebLink About2020-03-10 Stormwater Peer Review (HWG) Horsley Wiffen Group Sustainable F-tiviron merit l Solutiolril 112 water Street-60 Floor•Boston,MA 02109 857-283-810-horsleywitten.corn , March 10, 2020 Ms. Monica Gregoire, Staff Planner Planning Department Town of North Andover 120 Main Street North Andover„ Massachusetts 01845 Ref: Stormwater Peer Review 127 Marblehead Street, North Andover, MA Dear Ms. Gregoire and Board Members: The Horsley Witten Group, Inc. (HW) is pleased to provide the North Andover Planning Board with this letter report summarizing our initial peer review of the Site Plan and Operations & Maintenance Plan for the proposed project at 127 Marblehead Street, North Andover. The plans were prepared for Cen 1 Realty Trust (Applicant) by Christiansen & Sergi (a division of the Morin-Cameron Group, Inc.). The Applicant proposes to renovate an existing three-story building on a 4,500±square foot (sf) lot. The Applicant also proposes to install a sidewalk along Marblehead Street, as well as a permeable pavement driveway/parking area and an infiltration trench to manage stormwater generated from the new driveway. The Applicant has noted that the proposed site alterations represent a decrease in impervious cover of 695 sf; this assumes that the permeable pavement is not considered impervious. The project site does not appear to be within any wetland resource areas. The following documents and plans were received by HW: • Letter to Monica Gregoire, regarding Site Plan Review, 127 Marblehead Street, North Andover, Massachusetts, prepared by the Morin-Cameron Group, Inc., dated March 2, 2020 (6 pages); and • Site Plan for 127 Marblehead Street in North Andover, Massachusetts, prepared by Christiansen & Sergi, dated March 11, 2019 and most recent revised March 3, 2020 (Sheet 1 and 2 of 2). Stormwater Management Design Peer Review HW offers the following overall comments concerning the Stormwater management design as per the Massachusetts Stormwater Handbook (MSH) dated February 2008, the North Andover Stormwater Management and Erosion Control Regulations (Regulations) adopted February 5, 2011, and the North Andover Stormwater Management and Erosion Control Bylaw (Bylaw). The comments below correlate with the MSH standards and where the more stringent Town requirements are applicable additional comments are noted. &iorsleyWMd,Mxfor 6PIl...lorss ey%ttenGrokip IM Hordey Wiflein GrOUP, Town of North Andover March 10, 2020 Page 2 of 4 1. Standard 1 states that no new storm water conveyances may cause erosion in wetlands of the Commonwealth. a. The Applicant does not appear to be proposing any additional untreated stormwater conveyances toward a wetland resource area. It appears that the Applicant complies with Standard 1. 2. Standard 2 requires that post-development runoff does not exceed pre-development runoff off-site. a. The project qualifies as a redevelopment and is required to meet Standard 2 to the maximum extent practicable. b. The Applicant has indicated that the proposed driveway which will contain 6 parking spaces will consist of permeable pavement with an infiltration trench located along one edge. However, if feasible, for further stormwater improvements, HW recommends that all proposed walkways, sidewalks, and parking areas contain permeable pavement or permeable pavers. c. It appears that the existing asphalt located in front of the existing dwelling along Marblehead Street and Middlesex Street, as well as a portion of the existing driveway off Marblehead Street will be removed as part of the redevelopment. HW recommends that an as-built be provided to the Town upon completion to verify the areas have been removed as proposed. d. The Applicant has called for the use of 0.75"-1.5 diameter stone to be used in the proposed infiltration trench. Per MSH Volume 2, Chapter 2, HW recommends that the Applicant revise the Site Plan to call for 1,5"-3" diameter stone for the most "effective design." e. The Porous Pavement Detail appears reasonable. 3. Standard 3 requires that the annual recharge from post-development shall approximate annual recharge from pre-development conditions. a. The project qualifies as a redevelopment, and therefore needs to meet Standard 3 only to the maximum extent practicable. The Applicant intends to recharge the stormwater that lands on the proposed area of the 6 parking spaces. It appears that the Applicant complies with Standard 3. 4. Standard 4 requires that the storm water system be designed to remove 80% Total Suspended Solids (TSS) and to treat 0.5-inches of volume from the impervious area for water quality. a. The project qualifies as a redevelopment, and therefore needs to meet the structural BMP requirements of Standard 4 only to the maximum extent practicable. b. The Applicant has proposed a porous pavement driveway and an infiltration trench, both of which are able to provide stormwater treatment when functioning properly. To ensure that the infiltration trench does not receive a high sediment load during the construction period (which would inhibit function), HW recommends that the Applicant revise the Crushed Stone Infiltration Trench Detail to include a note stating IC.'Tf*c1sQ0I8118065 N Atidovcr On-Ca€\ISWO 127 NrIarbleheatI S1 27\4asI)lehead Streat.docx Town of North Andover March 10, 2020 Page 3 of 4 that"the infiltration trench is not to be installed until all upgradient contributing areas are fully stabilized," akin to that of the Porous Pavement Detail. 5. Standard 5 is related to projects with a Land Use of Higher Potential Pollutant Loads (LUHPPL). a. The project is not considered an LUHPPL and therefore Standard 5 is not applicable. 6. Standard 6 is related to projects with stormwater discharging into a critical area, a Zone Il or an Interim Wellhead Protection Area of a public water supply. a. The project site does not discharge into a critical area therefore Standard 6 is not applicable to this project. 7. Standard 7 is related to projects considered Redevelopment. a. The project site is considered a redevelopment under the definition: "development, rehabilitation, expansion and phased projects on previously developed sites, provided the redevelopment results in no net increase in impervious area." As such, the project is required to meet the following MSH Standards only to the maximum extent practicable: Standard 2, Standard 3, and the pretreatment and structural stormwater best management practice requirements of Standards 4, 5, and 6. Once the Applicant has addressed the relevant comments in this letter it appears that it complies with Standard 7. 8. Standard 8 requires a plan to control construction related impacts including erosion, sedimentation or other pollutant sources. a. The Applicant has not provided a sediment control plan, nor are sediment controls called out for on the Site Plan. HW recommends that the Applicant include the following sediment control measures: i. Per North Andover Regulations 8.1.c.ii, a construction sequence should be provided. Earthwork should not begin until erosion controls are installed. ii. Per Regulations 8.2.i, perimeter sediment controls should be installed around the site where practical. Additionally, catch basin inlet protection should be installed at any existing catch basins within 100 feet of the project site. Controls should be included on the Site Plans, as well as details. iii. Per Regulations 8.1.b.vii, the location of any material stockpile/staging area should be indicated on the Site Plans or a note should be added stating that no stockpiling will occur on site. iv. Per Regulations 8.2.t, if a construction entrance is anticipated for the site, it should be indicated on the Site Plans, and a sediment tracking pad should be included. 9. Standard 9 requires a Long-Term Operation and Maintenance (O&M) Plan to be provided. a. The Applicant has provided an O&M Plan, including a Long-Term Pollution Prevention Plan (LTPPP) and a Stormwater System Inspection Report template. HW has the following recommendations for the O&M Plan K:A11roject,12018',18065\.Andover On-Ca11v150650 127 AMaihlzhea l StrcetiRcpnrts' �p;09,_Pecr Revieir_127\Marblehead Strcet.doa3 Town of North Andover March 1O. 2O30 Page 4of4 i. The Applicant has noted that sand can be placed on the paved areas during the winter months, however sand should not bg placed on the permeable pavers. It will be difficult for m property owner tD remember which areas a||Ovv sand and which do not. HW recommends that all impervious walkways and driveways being maintained by the property owner are permeable and that the O&M Plan he revised to clearly document that sand should not beused. ii. The O&M Plan references the term "every major storm event." HVV [ecODlD18Dds that the Applicant define a major S[OrOBvanttobe an event with a D8iDiDlurn ofU.5 inches of precipitation. iii. Per Regulations 8.1.e.ii, the O&M Plan should bg signed by the property oVVDe[ iv. Per Regulations S.1.f. BMPa and other intended inspection items should he listed in the Report template tn ensure that their inspection occurs. 1O. Standard Y0 requires aD Illicit Discharge Compliance Statement bobgprovided. o. The Applicant has provided a Prevention of Illicit Discharges section within the LTPPP. HVV recommends that the Applicant provide a signed version of the Illicit Discharge Statement two weeks prior to the beginning of any earthwork. Conclusions HW recommends that the Planning Board require that the Applicant address these comments as part of the permitting process. The Applicant is advised that provision of these comments does not relieve them of the responsibility to comply with all Town of North Andover Codes and By-Laws, Commonwealth of Massachusetts |av*s, and federal regulations as applicable to this project. Please contact Janet Bernardo at 857-263-8193 or at jbernardo@horsleywitten.corn if you have any questions regarding these comments. Sincerely, M[)RSLEYVVlTTEN GROUP. INC. - L' � ��°�°� ��'m��° (l ~' —W r " Jonas Procton' E.I.T. Janet Carter Bernardo, P.E. Staff Engineer Senior Project K4onaQeF