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HomeMy WebLinkAbout231018_HW_SWPeerReview_492 Sutton Street Horsley Witten GroupSustainable Environmental Solutions 112 Wafer Street•80"Floor•Boston,AAA 02109 „ 857-263-8193•horsleywit¢en.com October 18, 2023 Ms. Jean Enright, Planning Director North Andover Planning Board 120 Main Street North Andover, Massachusetts 01845 Ref: Initial Stormwater Peer Review 492 Sutton Street North Andover, Massachusetts Dear Ms. Enright 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 review of the Stormwater Management Report and Site Plan for the proposed development at 492 Sutton Street, North Andover, MA. The plans and stormwater report were prepared by Hancock Associates on behalf of Home Grown Lacross, LLC (Applicant). The project proposes the construction of a 39,100 square foot (sf) athletic facility with office space, a parking lot, landscaping, utilities, and stormwater management on a 2.5-acre leased lot granted by the Lawrence Municipal Airport. The site is currently undeveloped and relatively flat, consisting of maintained grass fields, disturbed earth from removal of stockpiling, and some woods. A portion of the site is located within the Watershed Protection District including the 325-foot Non Discharge Zone. The Applicant proposes constructing a porous pavement parking lot with a subsurface reservoir to infiltrate runoff from the building roof and parking lot. The reservoir overflows to the municipal stormwater system on Sutton Street. The following documents and plans were received by HW: • Conceptual Renderings, HGR Sports Facility and Offices, prepared by The Meadow Lab, dated October 5, 2023 (7 pages); • Special Permit, Site Plan Review Application, 492 Sutton Street, North Andover, MA, signed by Bryan Brazill (4 pages); • Special Permit, Watershed Permit Application, 492 Sutton Street, North Andover, MA, signed by Bryan Brazill (2 pages); • Memorandum in Support of Application for Site Plan Review Special Permit and Watershed Special Permit, 492 Sutton Street, North Andover, MA, prepared by Smolak &Vaughan LLP, dated October 5, 2023 (9 pages); • Architecture Plans, HGR Sports Facility, prepared by The Meadow Lab, dated October 5, 2023 (23 sheets); • Stormwater Management Report, 492 Sutton Street, North Andover, MA, prepared by Hancock Associates, dated August 30, 2023 (45 pages); and Horsley%tMen.com 6 Horslley%tten rou Horsley Witten Group, Inc. Town of North Andover October 18, 2023 Page 2 of 6 • Permit Site Plan, Home Grown Lacrosse Sports Facility and Offices, 492 Sutton Street, North Andover, MA, prepared by Hancock Associates, dated August 30, 2023, which includes: o Title Sheet A-1 o Topographic Plan of Land A-2 o Layout and Materials Plan A-3 o Grading and Drainage Plan A-4 o Landscape and Lighting Plan A-5 o Swept Path Analysis and Staging Plan A-6 o Details 1 of 2 A-7 o Details 2 of 2 A-8 Stormwater Management Design Peer Review In accordance with the North Andover Zoning Bylaw §195-8.14. E. (8) A Stormwater management plan is required for all site plan review applications. The stormwater management plan shall be prepared in accordance with the latest version of the Massachusetts Stormwater Handbook (MSH) and demonstrate full compliance with the Massachusetts Stormwater Standards and the North Andover Stormwater Management and Erosion Control, Chapter 165 of the Town Bylaws. Chapter 165 further references Chapter 250. Stormwater Management and Erosion Control. HW offers the following comments concerning the stormwater management design. We have used the Massachusetts Stormwater Standards as the basis for organizing our comments. However, in instances where the additional criteria established in §250-27 of the North Andover Code requires further recommendations; we have referenced these as well. 1. Standard 1: No new stormwater conveyances (e.g., outfalls) may discharge untreated stormwater directly to or cause erosion in wetlands or waters of the Commonwealth. a. The Applicant has evaluated two discharge points from the project site. Under existing conditions stormwater from Subcatchment 1 S flows northwest towards Terminal Road. Stormwater from Subcatchment 2S flows southeast towards Old Clark Street. The existing site consists of grass and woods. There are no existing stormwater practices. b. The Applicant proposes to construct a porous pavement parking lot with a subsurface reservoir to infiltrate runoff from the proposed building roof and parking lot. The reservoir overflows to the municipal stormwater system on Sutton Street. The remainder of the site flows into the Terminal Road and Sutton Street/Old Clark Road drainage system. The site is not discharging to wetlands or waters of the Commonwealth. 2. Standard 2: Stormwater management systems shall be designed so that post-development peak discharge rates do not exceed pre-development peak discharge rates. a. In accordance with §250-22 B. (6) a summary of pre- and post-development peak rates and volumes of stormwater demonstrating no adverse impacts should be provided as part of the narrative. The Applicant has provided the peak flows and the peak volumes for the 2-year, 10-year, 25-year, and 100-year storm events under Documenting Compliance in the Stormwater Management Report. HW recommends that the Applicant provide a revised table if needed based on the comments below. I\2 M20 1u,,Nin o ,a:urviJh Aml;HrmV'?M201') KY::' A in StmnVd c P+nurvi:`231 118....SWPc nrRcn ac w..."q " ;o,ofl,on&rnd,door :,� Town of North Andover October 18, 2023 Page 3 of 6 b. In accordance with §250-22 B. (5) (a) a summary of proposed land area to be disturbed and existing and proposed impervious area should be provided as part of the narrative. HW recommends that the Applicant include the proposed land area to be disturbed and the existing and proposed impervious area in the narrative. c. The Applicant has modeled the porous pavement with a 597-minute time of concentration (Tc) and then routed it through a pond. HW does not agree with this methodology. The stormwater should flow through the porous pavement quickly and then will be held in the pond for an extended period as it infiltrates. Including the lengthy Tc and the pond is doubling the affect that the porous pavement will have. HW recommends that the Applicant revisit the model or justify its methodology. d. The Applicant has provided a detail for the porous pavement. HW has the following comments: i. Note #10 in the General Construction Sequence— Porous Pavement calls for 6 inches of 3/4" to 1" diameter stone. However, the figure and schedule of elevations show the depth to be 8 inches. HW recommends that the Applicant revise the depth listed in the note. ii. HW recommends that the Applicant add the installation of the underdrains, cleanouts, and OCS to the General Construction Sequence — Porous Pavement. iii. The figure calls out 4" SCH40 4" Perf. Pipe for the underdrain. However, the Porous Pavement Area Connections and Grading & Drainage Plan call for 6" Perforated ADS Pipe. HW recommends that the Applicant revise the detail accordingly. iv. HW recommends that the Applicant confirm if inspection ports are proposed for the porous pavement area and show their locations on the Grading & Drainage Plan. V. It appears that the reservoir layer for the porous pavement extends beyond the surface porous pavement area. HW recommends that the Applicant explain the installation process for this section of the stormwater practice and confirm if additional instructions or details are necessary on the plans. e. The porous pavement reservoir is proposed to overflow into the proposed OCS and be piped to a proposed offsite drain manhole. The connecting pipe is located very close to an existing catch basin (RIM = 153.88) on Old Clark Street. It is unclear how the existing catch basin ties into the street drainage system. HW recommends that the Applicant verify that the proposed pipe has adequate separation from the existing catch basin and that it does not conflict with the existing street drainage system. HW further recommends that the Applicant confirm that the North Andover Department of Public Works has reviewed the proposed drain manhole and the connection to the municipal system. f. The Applicant has provided existing and proposed subcatchment plans. HW recommends that the Applicant include the Tc Flow Paths for the existing subcatchment plan. g. HW recommends that the Applicant provide a typical pavement detail for the proposed I\2 M20 1u,,Nin o ,a:urviJh Aml;HrmV'?M201') KY::' A in StmnVd c P+nurvi:`231 118....SWPc nrRcn ac w..."q " ;o,ofl,on&rnd,door :,� Town of North Andover October 18, 2023 Page 4 of 6 driveway. h. The Applicant has provided a grass swale detail. HW recommends that the Applicant label the proposed grass swale on the north side of the site. i. The Applicant has provided a typical plan view detail for the outlet control structure (OCS). HW recommends that the Applicant provide the cross-section detail for the OCS as well. j. The proposed HydroCAD model for the porous pavement uses a 4-foot sharp crested rectangular weir for the OCS. HW recommends that the Applicant add this dimension to the OCS detail. k. The Applicant has provided a Cape Cod berm detail. HW recommends that the Applicant clarify where Cape Cod berm is proposed on the site and call it out in the plans. I. The Applicant has used precipitation values equal to or greater than the values provided by National Oceanic and Atmospheric Administration (NOAA)Atlas 14 for the 24-hour storm events, as outlined in §250-23 E. (19). No further action required. 3. Standard 3 requires that the annual recharge from post-development shall approximate annual recharge from pre-development conditions. a. The Applicant has provided recharge volume and drawdown calculations. HW recommends that the Applicant provided the stage storage data for the porous pavement system to confirm the volume provided below the lowest outlet (elevation 159.52). b. The separation from the bottom of the porous pavement system to the Estimated Seasonal High Groundwater (ESHGW) is 2 feet. The Applicant has provided a mounding analysis. It appears that mounding will not affect the recharge and drawdown provided by the proposed porous pavement system. HW has no further comment. 4. Standard 4 requires that the stormwater system be designed to remove 80% Total Suspended Solids (TSS) and to treat 1-inch of volume from the impervious area for water quality. a. The Applicant has provided a TSS worksheet that lists the porous pavement to provide the 90% TSS removal per the Town's requirements. According to MA MS4 General Permit 2.3.6a.ii.3.a3.2, the TSS removal efficiency of porous pavement is 90% if the storage bed is sized to retain 1" water quality volume drained within 72 hours. HW recommends that the Applicant address the comments under Standard 3 to satisfy this requirement. b. Per§250-23 B. (1) the Applicant is required to remove 60% of the average annual load of Total Phosphorus. The Applicant has noted that it removes 62% of the Phosphorus load via the 12-inch filter course in the porous pavement according to the MA MS4 General Permit Table 3-22 of Appendix F, Attachment 3. The Applicant has provided sufficient phosphorus removal. No further action required. c. The Applicant has noted in its narrative that the proposed stormwater system has been designed to treat one inch of water quality volume. Per §250-23 B. (1)(b) new developments are required to retain the volume of runoff equivalent to one inch multiplied by the total post-construction impervious surface or meet a combination of I\2 M20 1u,,Nin o ,a:urviJh AmA;Hrm,,2 M201') KY::' A in StmnVd c P+nurvi:`231 118....SWPc nrRcn ac w..."q " ;o,ofl,on&rnd,door :,� Town of North Andover October 18, 2023 Page 5 of 6 retention and treatment that achieves the above standards listed under §250-23 B. (1). It appears that the criteria have been met. No further action required. 5. Standard 5 is related to projects with a Land Use of Higher Potential Pollutant Loads (LUHPPL). a. The project is not considered a LUHPPL. Standard 5 is not applicable. 6. Standard 6 is related to projects with stormwater discharging into a critical area, a Zone ll, or an Interim Wellhead Protection Area of a public water supply. a. A portion of the project site closest to Old Clark Street is within the North Andover Watershed Protection District. In accordance with §195-4.19. B. (4)All construction in the Watershed Protection District shall comply with best management practices for erosion, siltation, and stormwater control in order to preserve the purity of the groundwater and the lake; to maintain the groundwater table; and to maintain the filtration and purification functions of the land. HW has listed comments under Standard 8 regarding erosion control practices for the project site. b. The existing conditions plan indicates that the boundary of the Watershed Protection District is through the middle of the project area. The proposed site layout illustrates the Non-Discharge Zone Watershed protection District only minimal crossing the project area. HW recommends that the Applicant clarify where the boundary is on the site plans. 7. Standard 7 is related to projects considered Redevelopment. a. The project is considered new development. Standard 7 is not applicable. 8. Standard 8 requires a plan to control construction related impacts including erosion, sedimentation, or other pollutant sources. a. The Applicant has included an erosion control barrier along the lease limit of the site and catch basin inlet protection to the Grading and Drainage Plan. HW recommends that the Applicant create an Erosion & Sediment Control Plan on a separate sheet in the plan set. The Erosion & Sediment Control Plan should also include a stabilized construction entrance and temporary stockpile locations. b. HW recommends that the Applicant include the Limit of Work (LOW) on all drawings within the plan set. c. The Applicant has provided a straw wattle detail that also shows a silt fence. HW recommends that the Applicant add more information about silt fence installation to the detail. d. According to the HydroCAD models, the Applicant proposes to decrease the woods on site by approximately 6,000 sf. HW recommends that the Applicant demonstrate which trees are proposed to be removed and which trees will be protected on the plans. e. HW recommends that the Applicant add a note stating, prior to any land disturbance activities commencing on the site, the developer shall physically mark limits of no land disturbance with tape, signs, or orange construction fence, so that workers can see the areas to be protected. The physical markers shall be inspected daily. f. The Applicant is proposing to disturb more than one acre of land. In accordance with the I\2 M20 1u,,Nin o ,a:urviJh Aml;HrmV'?M201') KY::' A in StmnVd k P+nurvi:`231 118....SWPc nrRcn ac w..."q " ;o,ofl,on&rnd,door :,� Town of North Andover October 18, 2023 Page 6 of 6 EPA Construction General Permit, the Applicant is required to file a Notice of Intent with the EPA and prepare a Stormwater Pollution Prevention Plan (SWPPP). HW recommends that the Applicant provide the Town of North Andover with a copy of the SWPPP a minimum of 14 days prior to land disturbance. The Planning Board may choose to require receipt of the final SWPPP signed by the contractor as a condition of approval. 9. Standard 9 requires a Long-Term Operation and Maintenance (O & M) Plan to be provided. a. The Applicant has provided an Operation and Maintenance Plan in the Stormwater Report. HW recommends that the O&M Plan become a standalone document to be signed by the owner. b. The Applicant has included the pervious pavement as a maintenance item in the O&M Plan. HW recommends that the Applicant clarify if inspection ports are proposed and mention them in the O&M Plan. c. HW recommends that the Applicant include the maintenance of the OCS and roof drains in the O&M Plan. d. HW recommends that the Applicant include a budget in the O&M Plan. e. HW recommends that the Applicant provide a simple plan, drawn to scale clearly noting all stormwater practices requiring long term maintenance. 10. Standard 10 requires an Illicit Discharge Compliance Statement be provided. a. The Applicant has provided an Illicit Discharge Compliance Statement in the Stormwater Report. HW recommends that the Town require the submission of the Illicit Discharge Statement signed by the property owner prior to discharge of stormwater to post- construction best management practices as a condition of approval. Conclusions HW recommends that the Planning Board require that the Applicant provide a written response to address these comments as part of the Board's review process. The Applicant is advised that provision of these comments does not relieve him/her of the responsibility to comply with all Town of North Andover Codes and By-Laws, Commonwealth of Massachusetts laws, and federal regulations as applicable to this project. Please contact Janet Bernardo at 508-833-6600 or at jernardo@horsleywitten.com if you have any questions regarding these comments. Sincerely, HORSLEY WITTEN GROUP, INC. n 13 Janet Carter Bernardo, P.E. Associate Principal I\2 M20 1u,,Nin o ,a:urviJh AmA;Hrm,,2 M201') KY::1 A in StmnVd c P+nurvi:`231 118....SWPc nrRcn ac w..."q " ;o,ofl,on&rnd,door :,�