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HomeMy WebLinkAbout2023-03-21 Stormwater Peer Review Horsley Wiffen Group Sustainable Environmental Solutions`, 112 Water Street w 811 Floor•Boston,MA 02109 857-263-8193-horsleywitten.com March 15, 2023 Ms. Jean Enright, Planning Director Planning Department Town of North Andover 120 Main Street North Andover, Massachusetts 01845 Re: Second Stormwater Peer Review Proposed Swimming Pool- 521 Dale 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 second review of the Watershed Special Permit Application and Plan of Land for the proposed swimming pool project at 521 Dale Street in North Andover, MA. The plans were prepared by Williams & Sparages on behalf of Tony and Lindsay Sallese (Applicant). The project proposes the installation of an in-ground swimming pool, paver patio, and chain link fence. The stormwater management for the proposed improvements includes a 12-inch wide, 2-foot-deep infiltration trench surrounding the pool and patio to allow stormwater from the patio to infiltrate into the ground during a storm event. In addition, the swimming pool will be equipped with a non-backwash filtration system. A total of approximately 1,500 square feet(sf)of additional impervious area is proposed within the parcel. The residential lot was created prior to October 24, 1994 and is located within the Watershed Protection District. The project is proposed within the Non-Discharge Zone from the edge of a wetland resource area located across Dale Street. The closest point of the proposed patio surrounding the pool is 239.5 feet from the wetland. The entire project is located outside of the 400-foot Non-Discharge Zone of Lake Cochichewick. In accordance with §195-4.19 B. (2)of the North Andover Zoning Bylaws, any surface or subsurface discharge of stormwater within the Non-Discharge Buffer Zone is only allowed after a special permit has been granted by the North Andover Planning Board. The following additional documents and plans were received by HW in response to our March 2, 2023 initial peer review letter: • Revised Watershed Special Permit Application, 521 Dale Street, North Andover, Massachusetts, prepared by Williams &Sparages, dated March 15, 2023 (7 pages); and • Plan of Land for 521 Dale Street, North Andover, Massachusetts, prepared by Williams & Sparages, dated February 16, 2023, revised March 15, 2023 (1 sheet). Stormwater Management Design Peer Review 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. Hors[eyWitten.corn 19(c HorsleyWittenGroup Horsley Witten Group, inc. Town of North Andover March 15, 2O23 Page 2of2 The following comments correlate with the March 2, 2023 initial peer review letter. Follow up comments are provided in bold font. 1. The Applicant states that the project kspropooedvviU)inthe ^Non-DiauhargeBufferZone^hnma bordering vegetated wetland, but the Applicant also states that this project is only subject to the requirements of§195-4.19 A"General Zone." HW recommends that the Applicant update the Application to indicate that the project ia subject to the requirements of§1Q5-4.10 B.. "Non- Diaoharge Buffer Zone." The Applicant has revised the Applicant, noting that the project is subject to the requirements of§1g6-4.18B. HVV has no further comment. 2. HVV recommends that the Applicant include erosion controls and indicate on the Plan where the stockpiles will be located during construction. HW also recommends that the Applicant indicate how the construction vehicles will access the backyard. The Applicant has included the stockpiles and construction access on the revised plan of land. HVV has no further comment. 3. The Applicant proposes that the swimming pool be equipped with a non-backwash filtration system. HW recommends that the Applicant include information about inspecting the filtration system in the Operations and Maintenance Plan. The Applicant has revised the O&M Plan to include the pool filtration system. HW has no further comment. 4. The Applicant proposes that the pool may be pumped into a drywell following storm events. HW recommends that the Applicant clarify the location of the drywell on the plan. The Applicant has revised the O&M Plan to indicate that when necessary, the pool should be pumped into the infiltration trench. IHW notes that the pool water should be daoh|or|natwd prior to being pumped to the infiltration system. 5. HW agrees that the infiltration trench surrounding the patio will provide adequate stormwater management for the additional impervious surface. No action required. 0o further action needed. Conclusions HW is satisfied that the Applicant has adequately responded to our comments. We appreciate the opportunity to assist the Town of North Andover un this project revimvv. P|emseoonbaotJanotBernordoot 508-833-6600orat if youhavoonyquaationanogandinQthouecommenh;. Sincerely, HORSLEYVV|TTEN GROUP. INC. Janet Carter Bernardo, P.E Associate Principal K\Pm|omo\2021\21V2O Town o[North Andover\210zON5c1 Dale atveobRwpvrt\23031o_2ndSVVPeodRavov—o21Da|*Sonm\.dmx Horsl ey Wiifien Group Sustainable Environmental Solutions 112 Water Street-6"Floor-Boston,MA 02109 857-263-8193•horsleywitten.com March 2, 2023 Ms. Jean Enright, Planning Director Planning Department Town of North Andover 120 Main Street North Andover, Massachusetts 01845 Re: Initial Stormwater Peer Review Proposed Swimming Pool - 521 Dale 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 Watershed Special Permit Application and Plan of Land for the proposed swimming pool project at 521 Dale Street in North Andover, MA. The plans were prepared by Williams & Sparages on behalf of Tony and Lindsay Sallese (Applicant). The project proposes the installation of an in-ground swimming pool, paver patio, and fence. The stormwater management for the proposed improvements includes a 12-inch wide, 2-foot-deep infiltration trench surrounding the pool and patio to allow stormwater from the patio to infiltrate into the ground during a storm event. In addition, the swimming pool will be equipped with a non-backwash filtration system. A total of approximately 1,500 square feet (sf) of additional impervious area is proposed on site. The residential lot was created prior to October 24, 1994 and is located within the Watershed Protection District. The project is proposed within the Non-Discharge Zone from the edge of a wetland resource area located across Dale Street. The closest point of the proposed patio surrounding the pool is 239.5 feet from the wetland. The entire project is located outside of the 400-foot Non-Discharge Zone of Lake Cochichewick. In accordance with §195-4.19 B. (2) of the North Andover Zoning Bylaws, any surface or subsurface discharge of stormwater within the Non-Discharge Buffer Zone is only allowed after a special permit has been granted by the North Andover Planning Board. The following documents and plans were received by HW: • Watershed Special Permit Application, 521 Dale Street, North Andover, Massachusetts, prepared by Williams & Sparages, dated February 21, 2023 (9 pages); and • Plan of Land for 521 Dale Street, North Andover, Massachusetts, prepared by Williams & Sparages, dated February 16, 2023 (1 sheet). HorsleyWitterixom V @Horsley /QftenGroup Hor dcy Wiften Group, dnc:. Town of North Andover March 2, 2023 Page 2 of 2 Stormwater Management Design Peer Review 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 the following comments regarding the proposed stormwater management design. 1. The Applicant states that the project is proposed within the "Non-Discharge Buffer Zone" from a bordering vegetated wetland, but the Applicant also states that this project is only subject to the requirements of§195-4.19A "General Zone." HW recommends that the Applicant update the Application to indicate that the project is subject to the requirements of§195-4.19 B., "Non-Discharge Buffer Zone." 2. HW recommends that the Applicant include erosion controls and indicate on the Plan where the stockpiles will be located during construction. HW also recommends that the Applicant indicate how the construction vehicles will access the backyard. 3. The Applicant proposes that the swimming pool be equipped with a non-backwash filtration system. HW recommends that the Applicant include information about inspecting the filtration system in the Operations and Maintenance Plan. 4. The Applicant proposes that the pool may be pumped into a drywell following storm events. HW recommends that the Applicant clarify the location of the drywell on the plan. 5. HW agrees that the infiltration trench surrounding the patio will provide adequate stormwater management for the additional impervious surface. No action required. Conclusions HW recommends that the North Andover Planning Board require the Applicant to address these recommendations as part of its review process. We appreciate the opportunity to assist the Town of North Andover on this project review. Please contact Janet Bernardo at 508-833-6600 or at ibernardo horsle witten.corn if you have any questions regarding these comments. Sincerely, HORSLEY WITTEN GROUP, INC. Janet Carter Bernardo, P.E. Sarah Bartlett Associate Principal Staff Scientist KAProjects\2021\21020 Town of Noilh Andover\21020N 521 Dale Street\Report\230302-1 st—SWPeerReview-521 DaleStreet.docx