Gunner Sub-CS 98042704/~7/95 ~ON 15:15 FAX 21~ 759
HALFF AS$OC
Ill Halff Associates
ENGINEERS * ARCHITECTS * SCIENTISTS
PLANNERS * SURVBYOR3
002
~616 NORTHW~$? R. AZ~ ~
OAU.AS, TEXAS
Carson-Salcedo-McWilliams
1201 Main Street
Dallas, Texas 75202
Attn: Mx. Michael Gonzales
Re: 37.77-acre ~ Subdiv~ion
Dear Mr. Gonzales:
April 27, 1998
AVO 16248
In response to your letters dated April 2, 1998 and April 16, 1998, it is my opinion that the
City of Coppell and the owner of this project would be better servcr if the ouflall pipe was elevated
above the splash pad in accordance with the detail we provided to you, especially when the pipe
size is relatively snudL The benefit of having an elevated towline is to better accommodat~
siltation in Or~c Creek which may clog the outfall.
It is my understanding that thc District has no r~sponsibility to maintain the pipes outfalling
into Grapevine Creek. This responsibility therefore falls to the City or the property owner.
Although we believe the elevated flowlinc to be a better design, we offer no objection since thc
potential negative impacts of the lower ouffall do not bear directly on the District or its facilities.
I do object to the "slope to match slope of exist. Bank (max. 3:1)." The design slope of the
channel is 4:1; therefore the slope of the headwall should al~o be 4:1. The District must be notified
to detcrminc how the outfall is to be configurcd if the existing slope is stecpcr than 4:1.
/-
I trust this responds to your request. Please call if you have any questions.
Sincerely,
HALFF ASSOCIATES, INC.
Don O. Brock, P. E.
Vice President
cc: Paul Phy
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