Northlake WE P1-6-CS 871023 PAWA-Winkelmann
& Associates, Ir~
October 23, 1987
Mr. John C. Karlsruher, PE
Ginn, Inc.
17103 Preston Road - LB 118
Dallas, Texas 75248
re: Grapevine Creek Floodplain Map Revisions
Floodplain at Moore Road
Dear Mr. Karlsruher:
The attached drawin~ is a copy of the area on Grapevine Creek we discussed
yesterday. As we discussed, the NortMake Woodlands East (NWE), Phase 6
project will be affected by ultimate conditions base-flood discharges
Grapevine Creek. The project itself does not adversely affect any of the
floods investigated, nor does the new Moore Road bridge affect NWE. If at
all possible, however, the minimum finish floor elevations on seven (7)
lots along Bethel $chool Road and Pelican Lane backing up to the Creek
should be as follows:
LOT Minimum FF elevation
As shown As required
1 463.4 466.0
2 464.2 466.0
3 464.6 466.0
4 465.1 466.0
5 465.6 466.0
16 465.1 465.5
17 465.0 465.5
Source:
1. Don A. Tipton, Inc. - Northlake Woodlands ]~ast, Phase 6 - As-built, c 1985
2. PAWA' Winkelmann & Associates, Inc. - Floodplain Hydraulic Study, Moore Road,
1987
12660 COlT ROAD, SUITE 200 - DALLAS, TEXAS 75251 - 214/661-9406
October 23, 1987 - Page 2
Mr. John C. Karlsruher, PE
Mr. Robert Porter of Don A. Tiption's office informed that actual finish
floor elevations are governed by sanitary sewer requirements and, thus, the
constructed elevations will most likely be greater than the minimum
elevations shown. However, as you can see, to get one foot of freeboard,
in the ultimate conditions base flood, it will be important to revise those
minimums. Lots 1, 2, and 3 may even experience flooding and lots 1 and 2
do not even meet the old nor the effective FIS freeboard requirements.
We are sending copies of the drawing and this letter to both the City of
Coppell and to Mr. Porter. If you need additional information or
background hydraulic data, please call.
Sincerely,
PAWA-Winkelmann & Associates, Inc.
Carl V. Anderson, PE
Vice President
enc lo sure
cc w/encl:
Robert Porter - Don A. Tipton, Inc.
Shohre Daneshrn&nd - City of Coppell
..
,001
/.
!
/
;
,)
'~' ~o. ' ~/