HomeMy WebLinkAbout240318_2nd_SWPeerReview - Correspondence - 115 WINTER STREET 3/18/2024 Horsley Wiffen GroupSustainable Environmental Solutions
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March 18, 2024
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 — 115 Winter 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
Zoning Variance Application for the proposed swimming pool project at 115 Winter Street in North
Andover, MA. The plans were prepared by Williams & Sparages on behalf of Adrianne and Adam
Ramos (Applicant). The project proposes the installation of an 18 foot by 38 foot in-ground
swimming pool, with a concrete patio, paver walkway and chain link fence. The stormwater
management for the proposed improvements includes a 24-inch wide, 2-foot-deep infiltration trench
along two sides of the 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.
The proposed pool is a 684 square foot (sf) permanent structure. The footprint of the existing house
is approximately 3,200 sf. A total of approximately 1,600 sf of additional impervious area including
the pool, patio and walkway is proposed within the 4.13-acre parcel.
The residential lot is located within the Watershed Protection District and was created after October
24, 1994. The project is proposed within a portion of the Non-Discharge Zone from the edge of a
wetland resource area located to the south of the existing house. The closest point of the proposed
patio adjacent to the pool is approximately 134 feet from the resource area to the south. The
proposed limit of disturbance is greater than 100 feet from the wetland resource area. 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. A portion of the project area is also located within
the 150-foot Non-Disturbance Zone. In accordance with §195-4.19 C. (2)(c) the proposed
project also requires the granting of a variance by the Zoning Board of Appeals. The Applicant
has applied for the variance from the ZBA.
The following documents and plans were received by HW in response to our intital review dated
February 21, 2024:
• Letter regarding Watershed Special Permit Application &Zoning Variance Application,
proposed Swimming Pool - 115 Winter Street, North Andover, Massachusetts, prepared by
Williams & Sparages, dated February 23, 2023—date error(16 pages); and
• Permit Site Plan, 115 Winter Street, North Andover, Massachusetts, prepared by Williams &
Sparages, revised February 23, 2024 (1 sheet).
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Town of North Andover
March 18, 2024
Page 2 of 3
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.
The following comments correspond to our initial peer review letter dated February 23, 2024. Follow-
up comments are provided in bold font.
1. The Applicant is subject to the requirements of§195-4.19 B., "Non-Discharge Buffer Zone."
§195-4.19 B refers to §195-4.19 C (3)for Prohibited Uses except as allowed by§195-4.19 C
(2)which includes (f) "construction of any accessory structure or expansion of any existing
structure by less than 25% of the gross floor area if the existing structure exceeds 2,500
square feet." The existing house at 3,300 sf has a footprint that exceeds 2,500 sf, and the
proposed accessory structure (swimming pool at 684 sf) is less than 25% of the gross floor
area. No further action required.
March 18, 2024: No further action requested.
2. The Applicant has included erosion controls on the Plan and has shown where the stockpiles
will be located during construction. HW recommends that the Applicant include an additional
mulch sock or silt fence surrounding the stockpiling area for erosion protection.
March 18, 2024: The Applicant has included erosion controls around the soil
stockpile. HW has no further comment.
3. The Applicant has proposed a construction access around the west and south side of the
house. HW recommends that the Applicant include construction matting to limit the tracking
of sediment offsite or onto the driveway.
March 18, 2024: The Applicant has included construction matting as suggested. HW
has no further comment.
4. The Applicant proposes that the swimming pool be equipped with a non-backwash filtration
system. HW recommends that the Applicant include a checklist log that includes inspecting
the filtration system as part of the Operations and Maintenance Plan.
March 18, 2024: The Applicant has included the maintenance documentation for the
filtration system. HW has no further comment.
5. The Applicant has noted in the O&M Plan that when during normal dewatering following
storm events, the pool water shall be pumped into the infiltration trench. HW notes that the
pool water should be dechlorinated prior to being pumped to the infiltration system.
March 18, 2024: The Applicant has added that the pool water should be dechlorinated
prior to being pumped into the infiltration system as part of the O&M Plan. HW has no
further comment.
6. HW agrees that the infiltration trench surrounding the patio will provide adequate stormwater
management for the additional impervious surface. No action required.
March 18, 2024: No further action requested.
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Town of North Andover
March 18, 2024
Page 3 of 3
Conclusions
HW is satisfied that the Applicant has adequately addressed our comments. We appreciate the
opportunity to assist the Town of North Andover with this project review. Please contact Janet
Bernardo at 508-833-6600 or at ibernardo(a)horslevwitten.com if you have any questions regarding
these comments.
Sincerely,
HORSLEY WITTEN GROUP, INC.
Janet Carter Bernardo, P.E.
Principal
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