HomeMy WebLinkAbout2013-04-02 Planning Board Supplemental Materials (118) Eggleston Environmental
32 Old Framingham Rd Unit 29 Sudbury MA 01776 tel 508.259.1137 fax 866.820.7840
March 15, 2013
North Andover Planning Board
1600 Osgood Street
North Andover, MA 01845
Attn: Judy Tymon, Town Planner
RE: Stormwater Review
110 Sutton Street
Dear Ms. Tymon and Board Members:
Per your request, I have conducted a technical review of the March 6, 2013 drainage
design packet submitted by the Neve-Morin Group in support of a Site Plan Special
Permit for the above-referenced project. Included in the materials I received and
reviewed were the following:
§ Project Report, Drainage Analysis & Riverfront Area Narrative of 110 Sutton
Street, North Andover, prepared by The Neve-Morin Group, Inc. and dated March
6, 2013.
§ Site Plans, 110 Sutton Street, Sheets 1-4 of 4, prepared for Nancy Chippendale’s
Dance Studios by The Neve-Morin Group, Inc. and dated February 15, 2013,
revised through March 6, 2013.
I also conducted a brief site visit on December 11, 2012 and have had several telephone
conversations with Scott Cameron of Neve-Morin to discuss the project.
My primary focus in this technical review is on the overall stormwater management
approach and design concepts used in the project, as well as its compliance with the
Town of North Andover’s zoning requirements for Site Plan Review, the Massachusetts
Department of Environmental Protection (DEP) Stormwater Management Standards and
Regulations, and the North Andover Wetlands Bylaw. It is my understanding that, due to
the proposed stormwater remediation work proposed, a Notice of Intent (NOI)
application for the project has been or will be filed concurrently with the Conservation
Commission. My review is aimed at assisting both the Planning Board and the
Conservation Commission in their respective reviews of the project.
The project site is a 1.24 acre property with an existing 6,467 sf dance studio and
associated parking. Most of the site is impervious and stormwater management is
presently lacking. With the exception of one roof drain, the entire property drains
overland directly to the adjacent Merrimack River. Due to the slope of the property and
110 Sutton Street, Stormwater Review 2
March 15, 2013
the resultant rate of runoff flow, this has over time led to erosion of the river bank at the
base of the parking lot and degradation of the riverfront area.
The proposed project includes construction of a 3,796 sf addition to the existing building,
in an area that is currently paved parking. The existing pavement in front of the new
building will be removed and replaced with loam and seed, and roof drainage from the
proposed addition will be discharged onto the new lawn area. In accordance with
previous recommendations, the proposed project also includes several measures to
improve the stormwater management on the existing site and prevent ongoing
degradation of the riverfront area. These include two sediment forebays to capture,
pretreat, and attenuate the rate of runoff from the pavement and a level spreader to
disperse the discharge along the river bank. Additional improvements to provide erosion
controls at the outlet of the existing 12-in roof drain and an 18-in municipal drain and
compensatory flood storage are also proposed.
My comments on the proposed plan are outlined below:
1. The project as currently proposed will provide significant improvement to the
stormwater management on the project site in an area where it can have the most
impact. While I would prefer to see the drainage from the new roof areas
infiltrated directly, the proposed discharge onto a pervious surface, in conjunction
with the net reduction in impervious area on the property, will provide additional
recharge and an overall reduction in both the rate and volume of direct runoff
from the site. More importantly, the proposed measures for handling the
pavement runoff at the base of the parking area will provide some level of water
quality treatment of the runoff discharged and prevent further erosion of the river
bank and riverfront area.
2. The work proposed within areas subject to Conservation Commission jurisdiction
under the Wetlands Protection Act and the North Andover Wetlands Bylaw is
both specific to the proposed stormwater improvements and integral to achieving
those improvements, and is consistent with the Stormwater Management
Standards for redevelopment projects. The proposed design also meets (exceeds)
the compensatory storage requirements for construction in a flood zone.
3. Construction of the stormwater management improvements should be
implemented during the first phase of the proposed addition, and during a period
of low flow in the Merrimack River.
4. I do recommend that a qualified engineer oversee the construction of the
stormwater management system to ensure that it gets built in accordance with the
plan and that the level spreader functions properly. Once built, it is important that
the system be routinely inspected and maintained in accordance with the O&M
plan to maximize its effectiveness and prevent failure of the system.
110 Sutton Street, Stormwater Review 3
March 15, 2013
I appreciate the opportunity to assist the North Andover Planning Board and
Conservation Commission with the review of this project, and hope that this information
is suitable for your needs. Please feel free to contact me if you or the applicants have any
questions regarding the issues addressed herein.
Sincerely,
EGGLESTON ENVIRONMENTAL
Lisa D. Eggleston, P.E.
C: Jennifer Hughes, Conservation Coordinator