2021-03-22 Stockman Review - 1087 Westhampton Rd
STOCKMAN ASSOCIATES LLC • P.O. BOX 9 • ADAMS, MA 01220
PHONE: 413-743-1372 • WWW.STOCKMANASSOCIATES.COM
March 22, 2021
Ms. Sarah LaValley, Conservation, Preservation, and Land Use Planner
Northampton Conservation Commission
Planning & Sustainability
210 Main St., Room 11
City Hall
Northampton, MA 01060
Re: Stormwater Management Report & Permit
1087 Westhampton Road
Northampton, MA
Dear Ms. LaValley and Commissioners:
Per request of our client, Mr. Tim Seney, the following letter has been provided in review
of the Stormwater Management Report for 1087 Westhampton Road in the City of
Northampton prepared by Berkshire Design Group (BDG) dated February 18, 2021 as
well as the subsequent Stormwater Management Permit Application approval by the
City of Northampton Department of Public Works. Also included with the review are the
March 22, 2021 Notice of Intent materials prepared by BDG. Stockman Associates LLC
has reviewed these documents under the MA Wetlands Production Act regulations [310
CMR 10.53(1)] and the City of Northampton Wetlands Protection Ordinance Chapter
337. We offer the following comments.
310 CMR 10.53(1)
In their May 28, 2020 Order of Conditions, the Northampton Conservation Commission
approved the construction of a single-family driveway and associated stormwater
management features within Buffer Zone to protected Bordering Vegetated Wetlands.
Prior to the start of work, the Order required that the permittee obtain a stormwater
permit for the development of a house and driveway from the Northampton
Department of Public Works (DPW). See special condition #34.
• The February 18, 2021 report and associated March 11, 2021 Stormwater
Permit Plan were approved by the City of Northampton DPW on March
11, 2021.
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• As the Commission is aware, based on their approval OOC, driveway
access to the house site cannot be obtained from the common drive to
the west due to denial from the City Planning Department. As such, the
driveway access is limited to Westhampton Road. In compliance with 310
CMR 10.53(1), the originally approved site plans as well as the newly
approved stormwater management plan, avoid impacts to protected
Bordering Vegetated Wetlands and limit Buffer Zone impacts, locating the
limit of work at least 50-FT from the BVW boundary.
• The approved stormwater management plan further complies with the
regulation of 310 CMR 10.53(1) by clearly defining the limit of disturbance,
requiring erosion controls, and preserving natural vegetation closer to the
protected BVW.
• Based on DPW approval and the materials prepared by Berkshire Design
Group, the stormwater management plan complies with the MA DEP
Stormwater Standards.
o The stormwater design utilized ground-truth soil data obtained from
the site.
o The stormwater design incorporates LID/ESSD techniques including
the creation of smaller subject catchment areas, rain garden and
infiltration basins. The stormwater design also mimics sheet flows to
the maximum extent possible. Stable (riprap) capture and
conveyance techniques are limited to areas were topographic
and Buffer Zone constraints apply.
o The design model utilizes the coefficient for pavement,
demonstrating forethought that although the driveway will be
gravel during construction, it may ultimately be paved. This results
in the infiltration system overperforming under gravel conditions
and appropriately performing should the driveway be paved.
• It is our opinion that the stormwater site plan revisions can be approved
by the Northampton Conservation Commission under the requirements of
special condition #34. However, it is our understanding that the permittee
is submitting a formal request for an Amended Order of Conditions, should
the Conservation Commission deem that process necessary for approval.
Northampton Wetlands Protection Ordinance Chapter 337
In their May 28, 2020 Order of Conditions, the Northampton Conservation Commission
denied the construction of a single-family driveway and associated stormwater
management features within Buffer Zone to protected Bordering Vegetated Wetlands.
Based on the Order and discussion during the requisite public hearing, the basis for
denial was attributed to concerns regarding stormwater management. Subsequent to
the denial a revised stormwater management plan has been prepared and approved
by the City of Northampton DPW.
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• Berkshire Design Group has calculated the proposed buffer zone impacts. The
limit of work associated with the driveway and stormwater management
features within the 50 feet to 100 feet from wetlands totals 20,599-SF. In
compliance with §337-10 Performance standards subpart E. (1), the proposed
work is less than 20% of the area within the 50-FT to 100-FT buffer zone (17.8%).
• In compliance with §337-10 Performance standards subpart E. (2), the limit of
work for the proposed project has been located outside of the 50-foot Protection
Zone.
• Furthermore, the construction of a single-family driveway to gain access to a
buildable upland is a limited project under 310 CMR 10.53(3)(e), which states
limited project status for “The construction and maintenance of a new roadway
or driveway of minimum legal and practical width acceptable to the planning
board, where reasonable alternative means of access from a public way to an
upland area of the same owner is unavailable…”. As such, under the City of
Northampton Wetlands Protection Ordinance, the proposed project meets the
exemption as a limited project under §337-10 Performance standards subpart E.
(2)(c).
• It is our opinion that the revised project complies with the applicable
Performance standards under the City of Northampton Wetlands Protection
Ordinance Chapter 337. More specifically, the revised stormwater management
plan employs LID/ESSD techniques and utilizes features that are designed to
improve water quality, prevent erosion, and promote groundwater infiltration.
Due to a scheduling conflict, I will likely be unable to attend the Commission’s April 8,
2021 public hearing. As such, I offer these comments in advance of the hearing for the
Commission’s consideration. Please do not hesitate to contact me with any questions or
comments at (413) 743-1372 or at emily@stockmanassociates.com.
Sincerely,
Emily Stockman, MS, PWS
Senior Scientist/Owner
Stockman Associates LLC
CC: Mr. Time Seney
Mr. Tom Miranda
Mr. Chris Chamberland (Berkshire Design Group)