SWM-CS 990413 (2)
APR-14-99 08,05 FROM, NCH ENGR
ID, 9724380770
PAGE 2
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ii! HaIff Ass~ciates, Inc.
6816 Northwwt Plaza Drive
DaNai, Texas 7~
(214) 348-6200
Fax (214) 139-70$
ENGlNl;ERS . ARCHITECTS . SCIEN'TlS'TS . PlANNERS . SURveYORS
MEMORANDUM
TO:
Curtis Ingli5
DIFW Airport
DAlE:
April 13, 1999
AVO= 17582
fROM:
B. CBVid LitUeton.
Emoil: dlittSetonCha1ff.ccm
SU8JECT:
O/FW DllIinage Guidelines
PROJECl': Southwest Cappel!
DraInage Study
Mr. Inglis, we met IUt monttl with Tracy Thompson, Doug Bryan and Mike Pyles to discuss the existing drainage
patterns In the northeuterly portion of airport prop8f1y and it5 effect on the Bethel Road drainage system In
Cappoll. In an ongoing dr8/flage study we at-. PrepBring on behalf of the City of Coppell and area property owners,
lhe "best" alttmative for the area *OU1d cell for storm water detention on properties that are yet to be dweloped.
The criteria recommended In tha report for the sizing of d8t8nticn filcilitil.limits runoff frorn devulop8d sites to not
exceed pre-dtavelopment rate. The sites wnk:h would be subject to this proposed m8Ster drainage plan InclUde:>>
uirpgrt property and two lites controlled by property owners In Cappel! who arc partidpating in the study. Some
existing developments In thili part of Coppell have incorporated detention into their site drainage .y.tams. This
concept will allow for betlvr IT1ilnagement of runoff and help oontml flooding along the tributary of GraplMne Creek
'Nfl arc affucting.
Mr. Pyles and Mr. Bryan IndAted that the airport mu~ control runoff to pre-<levelopment volumes and velocities.
We were rehKred to the airport Design Criteria Manual far tlarffication of this I'8qulremenl
Wu J1Wiewed the [)esjgn Cr1terla MIlnuallnd conferred with Don Brock, one of our engineers WOrking for the
airport, and were unable to dBWnnine if the Birport will requlm detention In de\leloprn~nts that may affect the
Bethel Road dralnagB system and the b1butary Df Gl'IlpeYlne Creek. Can you please help clarify the airport's
position l'89ardl"g the potential for drainage detention In this area. Also, can you plasse indicate other areas on
the lIiTllort property where dralnage detentiOn MI5 been Implementad.
Please call me to discuss this issue or to schedule B time when we ~n come over and visit with you regarding the
drainage reqlJiremeJrt$.
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