HomeMy WebLinkAbout2012-06-05 Planning Board Supplemental Materials (39) MERRIMACK ENGINEERING $ERVICES INC.�
PROFESSIONAL ENGINEERS • HAND SURVEYORS
66 pARK STREET• ANDOVER,MA 01810•(976)4783856.373-8721 •FAY(978)478.1446•ENERS MAIL IntoQmertlmock �In0.c6m
May 30, 2012
Mr Eugene Willis,PE
Town of North Andover DPW
Osgood Street
No Andover,Ma
RE:Loweil Five Site Plan
498 Chickering Road
No Andover,Ma
Dear Mr Willis;
Regarding the storm drainage runoff,the existing site has 24,594 square4'eet impervious
area (roof and pavement)on it and the proposed site developmentwill
wilion h ve 22,805
square feet impervious area on it(roof and pavement). ve
9 square
feet of impervious area is a 7%reduction in impervious area. The reduction in
impervious area will reduce the runoff from the site when Compared to the
predevelopment condition as that impervious area wilt be replaced with landscaping,
which has a lower curve number than the impervious.area.
ent
tion is
d in
In addition the nt condition 3 5%, and the slight reduction m slope will also oreduce the e
post development and delaying the runoff and thus slightly
time of concentration(making it longer) y1 g
reducing the peak runoff rate at the design point,
For this project pn the: redeve opment condition,fall runoff ended up attha the catch basin on Chickerig Road at Franklin Seet as the
ultimate design point as
location. The system, at that point,will then have a reduction of runoff into it.
Please do not hesitate to contact me should you have further questions or comments.
Very ly 0
G EKING SERVICES
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Step
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