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CIVILDEVELOPMENT,
CIVIL ENGINEERING&DESIGN-BUILD SERVICES
P.O. Box 11929 College Station, Texas 77842 • Phone: 979-764-7743 • Fax: 979-764-7759
ADDENDUM TO DRAINAGE REPORT— 11/2006
SOUTH HAMPTON SUBDIVISION —PHASE 4
NANTUCKET SUBDIVISION— PHASE 7
COLLEGE STATION, TEXAS
This Addendum is in response to water levels observed following the recent significant rainfall event in
the existing drainage channel along the rear of Lots 8 & 9 in Block 1 of the Nantucket Subdivision —
Phase 7 and Lot 1 of Fairhaven Cove. This Addendum sets the minimum finished floor slab elevations
for the residential structures to be constructed on Lots 6, 7, 8 & 9 of Nantucket Subdivision, Phase 7.
The minimum finished floor elevations are shown on the attached Exhibit A, and are as follows:
Block 1 Lot 6 Min. FF=267.5
Block 1 Lot 7 Min. FF=267.0
Block 1 Lot 8 Min. FF=266.0
Block 1 Lot 9 Min. FF= 265.5
Also shown on Exhibit A are the finished floor elevations for the existing structures on Lots 1, 2 & 3 of
Fairhaven Cove and the top-of-road elevations of Nantucket Drive from Ballyough Lane to Harper's
Ferry Drive.
The finished floor elevations shown on Exhibit A are higher than the top-of-road elevation for any part
of Nantucket Drive in this vicinity. Stormwater runoff that exceeds the capacity of the two culverts
under Nantucket Drive will encroach onto the adjacent lots but will not damage existing residential
structures or the proposed residential structures if constructed to the minimum finished floor elevations
provided in this addendum. The runoff will flow over Nantucket Drive during major storm events, thus
preventing water levels in the existing drainage channel from rising to the finished floor elevations of
existing or proposed residential structures.
To minimize the amount of runoff encroaching onto the residential lots in this area, the two culverts
under Nantucket Drive and all other existing drainage facilities downstream of Nantucket Drive need to
be cleaned regularly and maintained in good operating condition.
A detailed drainage study of the hydrology and hydraulics of the existing drainage channel and the
culverts at Nantucket Drive would need to be performed in order to determine the maximum water
surface elevations and limits of the water onto the adjacent lots for the various rainfall events.
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