11C-001C meadowcrest farms conservationALMER HUNTLEY, JR. & ASSOCIATES, INC.
SURVEYORS - ENGINEERS - LANDSCAPE ARCHITECTS
P.O. Box 568 / 30 INDUSTRIAL DRIVE FAST / NORTHAMPTON, MASS. 01061
)413) 584 -7444
December 3, 1987
City of Northampton
Planning Board
City Hall
Northampton, MA 01060
ALMER HUNTLEY, JR., PE., RLS
DOUGLAS W. THOMPSON, RLS
WILLIAM R. GARRITY, LA
JOHN G. RAYMOND, PE
RE: #330 -262
Drainage System Revisions
for "Meadowcrest Farms"
Florence Street, Leeds
Dear Board Members:
The revisions contained in this submittal are based on a hydrological study
prepared for this site dated October 7, 1987. Since there has been significant
discussion on the issue of introducing increased flows to the beginning of an
existing drainage ditch, our client, Alexander MacPhail, has instructed us to
insert a smaller detention basin directly to the west of the previously proposed
detention basin.
This additional basin will direct runoff from the more frequent storms into a
newly proposed drainage ditch within newly proposed deed restrictions, along the
easterly property line of Lots 1 and 2. In turn, this will reduce the outflow
from the previously designed "lower" basin and thus reduce the runoff flow rates
at the beginning of the existing drainage ditch on the abutting driving range
property. The runoff intercepted by the newly proposed drain and ditch con-
verges with the discharge from the originally proposed lower basin, upstream of
Design Section B, as detailed in the previous report. At this design point and
beyond, the estimated flows are slightly less but do not vary significantly from
those previously calculated. For this revised drainage system, the flow reduc-
tions and redistribution are summarized in the following table for the 10- and
100 -year design storm.
Flows in CFS, Elevations in Feet
10 -Year Storm 100 -Year S torm
Location /Description
I. Peak inflow into additional
upper basin
2. Peak outflow from additional
upper basin into the proposed
ditch
Previous Present Previous Present
Design Proposal Design Proposal
N/A
27
N/A
46.8
N/A
8.1
N/A
8.3
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