HomeMy WebLinkAbout230427 HW_1st Peer Review Letter - - 185 GREAT POND ROAD Horsley Witten GroupSustainable Environmental Solutions
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857-263-8193•horsleywit¢en.com
April 27, 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 — 185 Great Pond Road
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 185 Great Pond Road in North Andover, MA. The
plans were prepared by Williams & Sparages on behalf of Tammy Woolfolk and Hans H. Kim
(Applicant). The project proposes the installation of a 14 foot by 30 foot in-ground swimming pool,
with a paver patio, and a fence. The stormwater management for the proposed improvements
includes a 12-inch wide, 2-foot-deep infiltration trench surrounding 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 420 square foot (sf)
permanent structure. The footprint of the existing house is approximately 3,200 sf. A total of
approximately 1,500 sf of additional impervious area including the pool and paver patio is proposed
within the 4.20-acre 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 to the rear of the existing house. The closest point of the proposed
patio surrounding the pool is approximately 113 feet from the resource area to the south. The
proposed limit of disturbance is greater than 100 feet from the wetland resource area. The entire
project is located outside of the 100-foot Non-Disturbance Zone. 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, 185 Great Pond Road, North Andover,
Massachusetts, prepared by Williams & Sparages, dated April 14, 2023 (13 pages); and
• Plan of Land for 185 Great Pond Road, North Andover, Massachusetts, prepared by
Williams & Sparages, dated April 14, 2023 (1 sheet).
Horsiey%tMen.com 6 Horslley%ttenGrou Horsley Witten Group, Inc.
Town of North Andover
April 27, 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 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 has a footprint that exceeds 2,500 sf, and the proposed
accessory structure (swimming pool) is less than 25% of the gross floor area. No further
action required.
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.
3. The Applicant has proposed a construction access to the back yard around the south side of
the house. HW recommends that the Applicant include construction matting to limit the
tracking of sediment offsite or onto the driveway.
4. The Applicant proposes that the swimming pool be equipped with a non-backwash filtration
system. HW recommends that the Applicant include information and a checklist log about
inspecting the filtration system in the Operations and Maintenance Plan.
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.
6. 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 with this project review. Please contact Janet Bernardo at 508-833-6600 or at
jbernardo(a-)horsleywitten.com if you have any questions regarding these comments.
Sincerely,
HORSLEY WITTEN GROUP, INC.
P 4
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Janet Carter Bernardo, P.E. Steve Stanish, P.E.
Associate Principal Senior Engineer
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