Creekview Add PD-CS 931208 NATHAN D. MAIER
CONSULTING ENGINEERS, INCL
December 8, 1993
Dewberry & Davis
Attn: Jerry W. Sparks
8401 Arlington Blvd.
Fairfax, VA. 22031
RE: As-Built Conditions, (r~eek View Addition, ~
Coppeil, Texas ~ J
NDM No.: 87-06-067
Dear Mr. Sparks:
Endosed are copies of the following HEC-2 runs for the subject tract:
GRENC. OUT- Summary output for FEMA's GRENC reruns on May, 1991 PC Version of HEC-2
w/Floodway
GREXIST.OUT - Summary output for FEMA's GREXIST reruns on May, 1991 PC Version of HEC-2-
Multiple Profiles
GABRENC.OUT - Input and output for Creek View Addition As-Built Conditions w/floodway
GABMULT.OUT - Summary output for Creek View Addition As-Built Conditions-Multiple Profiles
The as-built conditions models were truncated at Section 25685, three sections upstream of Denton Tap
Road Bridge. As indicated on the Water Surface Elevation Check forms, the tie-in is within 0.5' at this
location.
You will note a difference in water surface elevations at Denton Tap Road between the two versions of
HEC-2 (1985-1991). The Corps of Engineers advised us that there was an error in the 1985 version in the
way it used BT Cards for weir flow calculations. This was corrected In the 1991 version. Therefore, in
any profiles in which weir flow occurs, there will be a difference, albeit small.
I am also returning your diskette with the two as built conditions models on it.
If you have any further question, please call.
Sincerely,
NATHAN D. MAIER
Enclosures {6)
~-AM/siS
~.' ICM. Griffin, P.E.
City Engineer, Coppell w/o Enclosures
Three NotthP&rk / 8800 N. (2earful Expw¥. / Suite 300 / Dallas, Tex&s ?$23! / (2!4) 739-474!