Vista Ridge Retail-CS070823~ Winkelmann
&Associates, Inc.
CONSULTING CIVIL ENGINEERS ~ SURVEYORS
August 23, 207
Mr. Ken Griffin, P.E.
City of Coppe!!
255 Parkway Blvd.
Coppell, Texas '5019
Re: Vista Ridge Retail
NEC SH 121 ~ Denton Tap Rd.
Mr. Griffin:
V4'e have reviewed the arainace for the above referenced facilit;~ to determine if the TxDot
downstream system is desigrsed to adequately convey the design flow.
:'attached is a drawing showing the overall drainage area map for the area. We feel the areas are
conservative in nature. We have also established what we believe are runoff coefficients that are
come^/ative in nature as well.
based on both conservative numbers together, we feel the 10X10 box downstream of SH ~ 21 has
adequate capacity to Canvey `the design runoff from the subject tract and the overall drainage basin.
As a result, we are eiimiriating detention from our plans as attached.
Should you have any cuestions, please fee! free to call me at your convenience.
Sincerely,
WENKEL~ANN & ASSJCIA~ES, lNC.
Michael G, Clark, i~.E.
Vice President
MDC/ljm
Attachment
cc: .Jim Stabler
[.,avid D~.anning
Michael Doggett
1995
G:~(3TfIC~ C(~~~r~t~f~~~'.bi~~®r1f~IDn-i.ItL~~1~`~"(~~63~~~t1'. ~-~®~T~490-7090 Fax (972) 490-7099