HomeMy WebLinkAboutConsultant Review - 858 GREAT POND ROAD 2/17/2011 Eggleston Environmental
February 17, 2011
North Andover Planning Board
1600 Osgood Street
North Andover, MA 01845
Attn: Judy Tymon, Town Planner
RE: Watershed Special Permit Review
858 Great Pond Road
Dear Ms. Tymon and Board Members:
Per your request, I have conducted an initial technical review of the January 28, 2011
Watershed Special Permit Application packet for the above-referenced project, prepared
by Sullivan Engineering Group, LLC on behalf of David & Gay Tray. The proposed.
project entails the addition of an expanded living room and a second story to an existing
single family home, as well as a covered walkway and an additional garage bay. The
entire project is located within the Non-Disturbance Zone of the Watershed Protection
District.
My comments on the application are outlined below:
1. The proposed increase in Total Gross Floor area, including the second story
addition, is not enumerated in the application; however it does appear to exceed
the 50 percent allowed by Special Permit in the Non-Disturbance Zone.
2. The site development plan calls for a 500-gallon drywell to infiltrate roof runoff
from a portion of the roof of the house. While I would prefer to see the drainage
calculations based on the hydraulic conductivity of the native soil and not the
percolation rate (hydraulic conductivity tends to be more conservative), it is
apparent that the proposed drywell has adequate capacity to store and infiltrate the
additional runoff generated by the 546 sf increase in impervious area. It is not
clear, however, what will happen to the roof runoff from the remaining (larger)
portion of the house. Sheet 4 of the architectural plans indicates that the entire
house roof is to drain through downspouts to a perimeter drain system, and then to
a drywell. It appears likely therefore that a second drywell is needed.
3. The plans do not show how roof runoff from the expanded garage will be
handled. To the extent possible, roof drainage should be directed away from
pavement surfaces (e.g. the existing driveway) and infiltrated onsite, e.g. through
drywells or a drip trench.
4. The application indicates that a deed restriction will be placed on the property
restricting fertilizers to be organic or slow-release nitrogen. I suggest that this
55 Old Coach Road SUdbury M,4 01776 tel 508.259.1137 fax 866.820.7840
858 Great Pond Rd, Technical Review 2
February 17, 2011
deed restriction also prohibit the use of non-organic pesticides and herbicides on
the property in order to protect the town's drinking water supply.
I appreciate the opportunity to assist the North Andover Planning Board 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,
EGGLESSTON EN,rVIRONMENTAL
Lisa D. Eggleston, P.E.