Oakbend Addn-CS 930224DA,~ M. DOWDEY AND ASSOCIATES, _ ~C.
CIVIL ENGINEERS
16250 DALLAS PARKWAY SUITE 100
DALLAS, TEXAS 75248
(214) 931-0694 FAX (214) 931-9538
February 24, 1993
Mr. Kenneth M. Griffin
City Engineer
City of Coppell
P.O. Box 478
Coppell, Texas 75019
Re:
Oak Bend Estates
Proposed Pedestrian Bridge
Dear Mr. Griffin:
We are submitting a HEC-II study included with the revised
pedestrian bridge details from Lissiak Engineers, Inc. Also
included is a grading plan showing existing topographic
information, HEC II Sections and 100-year flood elevations. The
Albert Halff Storm Water Study was used to determine the beginning
water surface elevation and the quantity of flow for Stream Cl.
The HEC-II run revealed a 100-year water surface elevation of
497.30 at the proposed bridge. The low chord elevation of the
~~ian bridge has been set at 498.60, allowing for 1.30 feet of
freeboard. -~J ~'
An addition HEC-II study was run showing the bridge in section
number 1095. The 100-year water surface elevation does not change
with the addition of the pedestrian bridge.
If you should have any questions concerning this issue, please feel
free to contact me at your convenience.
Sincerely,
Michael S. Dowdey~