HomeMy WebLinkAbout251212_HW_2nd_SWPeerReview_243 Great Pond Road - - 243 GREAT POND ROAD Horsley Witten GroupSustainable Environmental Solutions
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December 12, 2025
Ms. Jean Enright, Planning Director
Planning Department
Town of North Andover
120 Main Street
North Andover, Massachusetts 01845
Re: Second Stormwater Peer Review
243 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 report summarizing our second review of the Watershed Special Permit Application for the
proposed improvements at 243 Great Pond Road in North Andover, MA. The plans were prepared
by Patriot Engineering LLC on behalf of Stephen Boyko (Applicant). The project proposes the
removal of an existing sports court area to accommodate a proposed 24-foot x 36-foot greenhouse
structure. The stormwater management for the proposed improvements includes a 2-foot wide by 2-
feet deep stone trench drip edge to capture and infiltrate the roof runoff from the proposed
greenhouse. The Applicant has noted on Sheet C-3 that the existing impervious area of the site is
9,473±square feet (sf). The total impervious area to be removed is 1,801±square feet, and the total
proposed impervious area to be constructed is 1,243± square feet. A total reduction of 558± square
feet of impervious surface area is proposed within the 2.47-acre parcel. It appears that the total land
disturbance is approximately 26,000 sf.
The residential lot is located within the Watershed Protection District and was created in 1965,
before October 24, 1994. The lot is located within the urbanized area, and the area of disturbance is
less than 1 acre. Most of the project area is within the 200-foot Riverfront Area of an unnamed
perennial stream. The limit of work is within the 50-foot No Build Zone from the edge of a bordering
vegetated wetland (BVW) to the west of the parcel. A second BVW, including a potential ephemeral
pool, is located on the northern side of the parcel. The closest point of the proposed greenhouse to
the western BVW is approximately 100 feet. The closest point of any construction activity is the
proposed Construction Fence along the proposed limit of work, which is approximately 25 feet from
the western BVW. The proposed limit of disturbance is greater than 25 feet from the wetland
resource area. In accordance with §195-4.19 B.(2)(a) 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 proposed project is within the jurisdiction of the North Andover Conservation Commission.
The following documents and plans were received by HW in response to our initial review letter
dated November 4, 2025:
• Letter to Jean Enright, regarding Review of 243 Great Pond Road, North Andover, MA,
prepared by Patriot Engineering LLC, dated November 21, 2025 (3 pages);
Horsiey%tMen.com 6 Horslley%ttenGrou Horsley Witten Group, Inc.
Town of North Andover
December 12, 2025
Page 2 of 4
• Stormwater Analysis and Calculations, 243 Great Pond Road, North Andover, MA, prepared
by Patriot Engineering LLC, revised November 21, 2025 (40 pages); and
• 243 Great Pond Road, Greenhouse Site Plan, North Andover, MA, prepared by Patriot
Engineering, dated October 29, 2025, revised November 21, 2025:
o Cover Sheet Sheet C-1
o Construction Management Plan Sheet C-2
o Conservation Site Plan Sheet C-3
o Construction Management Plan (details) Sheet C-4
o Drainage Area Map Sheet C-5
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 and recommendations regarding the proposed stormwater
management design. Follow up comments are provided in bold font.
1. The Applicant has included erosion controls including proposed construction fencing and a
12-inch filtermitt on the Construction Management Plan and has shown where the stockpiles
will be located during construction.
December 12, 2025: No further action is requested.
2. The Applicant has proposed a temporary construction entrance around the south side of the
house. HW recommends that the Applicant consider construction matting or other measures
to minimize the tracking of sediment onto the driveway and offsite per§250-25.E.(13) of the
North Andover Code.
December 12, 2025: The Applicant has added a Cross Section of the Construction
Entrance to Sheet C-2. No further action is requested.
3. It appears that the earthwork proposed will be contained to the area of the existing basketball
court and the construction of the proposed greenhouse. HW recommends that the Applicant
confirm that the area surrounded by the proposed post& rail fence will not be altered.
December 12, 2025: The Applicant has included a note on the Overall Site plan
indicating the extent of earthwork. No further action is requested.
HW notes that there is a call out on the Site Plan, Sheet C-3, for a Chain link fence. The
fence is not obvious on the site plans. HW recommends that the Applicant remove the
callout or add the fence for clarity.
4. The Stormwater Analysis and Calculations report does not include an existing drainage area
figure. The Applicant has provided an existing conditions catchment area 2S with a total area
of 24,908 sf. The paved area includes 4,340 sf. HW could not confirm the limits of the
Town of North Andover
December 12, 2025
Page 3 of 4
catchment area and could not determine if any of the existing house was included as part of
the paved parking area. HW recommends that the Applicant provides an existing catchment
area figure to confirm the values listed in the HydroCAD model for catchment area 2S.
December 12, 2025: The Applicant has provided an Existing Drainage Area Map as
requested. The areas delineated appear reasonable. No further action is requested.
5. The Applicant has not included a proposed catchment area figure. It has listed proposed
catchment area 5S as having 24,908 sf. The paved parking area includes 3,691 sf. The
Applicant has also included proposed catchment area 3S with a proposed DRIVE area of
890 sf. HW assumes that catchment area 3S is associated with the proposed greenhouse
and agrees that the area modeled is reasonable. However, HW believes that the catchment
area modeled as 3S should be subtracted from the catchment area modeled as 5S. HW
recommends that the Applicant provides a proposed catchment area figure to confirm the
values listed in the HydroCAD model for catchment area 3S and 5S.
December 12, 2025: The Applicant has provided a Proposed Drainage Area Map as
requested. The areas delineated appear reasonable. No further action is requested
6. HW recommends that the Applicant clarify the total impervious area to be removed and the
total proposed impervious area to be constructed. We could not confirm the values provided
on Sheet C-3.
December 12, 2025: The Applicant has added the impervious areas within the
Riverfront Area Calculation table and it is reducing the total impervious area by 558 sf.
The values appear reasonable. No further action is requested.
7. The Applicant has modeled the existing and proposed soil conditions as hydrologic soil
group (HSG)A. In accordance with the Natural Resources Conservation Service (NRCS)the
soils are HSG B or B/D. HW recommends that the Applicant revise the HydroCAD model
accordingly.
December 12, 2025: The Applicant has adjusted the HydroCAD model as suggested.
No further action is requested.
8. The Applicant has included an exfiltration rate of 1.02 inches per hour(iph) in the HydroCAD
model for the Stone Trench. HW recommends that the Applicant provide soil testing or other
documentation to confirm the exfiltration rate used.
December 12, 2025: The Applicant conducted one test pit and provided the data on
Sheet C-3. The soil was classified as Loamy Sand and the estimated seasonal high
groundwater(ESHGW) level was documented at 149.5. The HydroCAD model includes
an exfiltration rate of 2.41 iph which is reasonable for Loamy Sand and a bottom of
trench elevation of 152.0 which is greater than 2 feet above the ESHGW. No further
action is requested.
9. The HydroCAD model for the Stone Trench includes a 20 foot long by 1.0-foot-wide broad
crested weir at elevation 155.95. HW recommends that the Applicant clarify where this is
proposed on the site plans. HW notes that the plans include a proposed 156 contour grade
Town of North Andover
December 12, 2025
Page 4 of 4
line around the Greenhouse, HW further notes that during a 100-year storm event the stone
trench will overtop the proposed weir.
December 12, 2025: The Applicant has adjusted the length of the weir to be 10 feet
long and has called out the location of the weir on Sheet C-3. The proposed 156
contour has also been adjusted to accommodate the weir. No further action is
requested.
10. HW recommends that the Applicant clarify if any existing trees will be removed as part of the
proposed project.
December 12, 2025: The Applicant has stated that no existing trees will be removed as
part of this project. No further action is requested.
11. HW notes that the Erosion and Sedimentation Control Measures narrative lists the Town of
Lexington. HW recommends that the Applicant revise this to read North Andover.
December 12, 2025: The Applicant has corrected the Erosion and Sedimentation
Control Measures narrative as suggested. No further action is requested.
12. HW notes that the Applicant mentions a subsurface infiltration system in the narrative
numerous times. It is HW's understanding that the proposed stormwater practice is a drip
edge stone trench to manage the roof runoff from the proposed greenhouse. HW
recommends that the Applicant modify the narrative to avoid confusion or provide the design
information for the subsurface system.
December 12, 2025: The Erosion and Sedimentation Control Measures narrative still
mentions a subsurface infiltration system numerous times. In the two paragraphs
titled Debris and Litter Removal and in the After Construction - Inspection Schedule
and Evaluation Checklist. HW recommends that the Applicant modify the narrative to
avoid confusion or provide the location of the subsurface system.
Conclusions
HW recommends that the North Andover Planning Board requires that the Applicant provides a
written response to address the few outstanding 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 jbernardo(cDhorsleywitten.com if you have any questions regarding these comments.
Sincerely,
HORSLEY WITTEN GROUP, INC.
pp
Janet Carter Bernardo, PE
Principal