Villages C P3&4-CS 900302- DM NATHAN D. MAIER
CONSULTING ENGINEERS, INC.
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March 2, 1990
Mr. Russell oyl e��
City of Co ell
P.O. Box 78
Coppel Texas 75019
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Re: Villages of Coppell, Phase III I
NOM Job No.: 84- 10-054
Dear Mr. Doyle: y it , Ja�t
O
The following data provides an update of our February 16, 1990, report con erning the existing flood-
plain conditions with respect to the Villages of Coppell, Phase III. These revisions are provided due to
revisions in hydraulic models for this area. The following summarizes the revisions with respect to the
individual flooding sources.
Elm Fork Trinity River
The recent study submitted to the City of Coppell by Ron Morrison shows an existing hydraulic model
for the Elm Fork which is based on the ongoing Reconnaissance Study for the Corps of Engineers. The
report also provides an ultimate conditions model, which agrees with our report of February 16, 1990.
Table 1 summarizes the 100 -year water surfaces for both of these hydraulic models.
TABLE 1
Elm Fork Trinity River
First floors of residences will now be based on two feet above the new existing condition since this ele-
vation will control. The floodplain limits shown on the attached maps show the limits of the ultimate
floodplain elevation along the perimeter of the property as shown in Table 1.
The recent study submitted to the City of Coppell also provides revised hydraulic models for Denton
Creek. Table 2 provides a summary of the new existing conditions and ultimate discharges with exist-
ing hydraulic sections.
Three North Park /8800 N. Central Expwy. /Suite 300 /Dallas, Texas 73231/(214) 739 -4741
EXISTING
ULTIMATE
CROSS
RECONNAISSANCE
100 -YEAR
SECTION
MODEL
ELEVATION
1000 +40
447.09
447.59
1030 +60
448.49
448.97
1060 +80
451.52
451.95
First floors of residences will now be based on two feet above the new existing condition since this ele-
vation will control. The floodplain limits shown on the attached maps show the limits of the ultimate
floodplain elevation along the perimeter of the property as shown in Table 1.
The recent study submitted to the City of Coppell also provides revised hydraulic models for Denton
Creek. Table 2 provides a summary of the new existing conditions and ultimate discharges with exist-
ing hydraulic sections.
Three North Park /8800 N. Central Expwy. /Suite 300 /Dallas, Texas 73231/(214) 739 -4741
Mr. Russell Doyle
March 2, 1990
Page 2
TABLE 2
Denton Creek
First floor elevations will be established at 2 feet above the revised existing 100 -year elevations pro-
vided in Table 2, since these elevations will still control. The attached maps provided with this letter
show a floodplain delineation based on the ultimate flood elevation provided in Table 2.
Please supplement our previous report with these revised data. Since Mr. Morrison will be reviewing
this report, I have taken the liberty to send him a copy of this letter and maps.
If you have any questions concerning this data, please fell free to call me.
Sincerely,
NATHAN D. MAIER
CONSULTING ENGINEERS, INC.
William L Wallace, P.E.
WLW /slg
Enclosures
cc: Mr. Ronald Morrison
REVISED
CROSS
100 -YEAR
ULTIMATE
SECTION
EXISTING
100 -YEAR
ELEVATION
ELEVATIONS
18440
452.12
452.38
19330
452.25
452.51
19930
452.25
452.51
21560
452.39
452.67
22370
452.58
452.90
23800
452.98
453.38
24700
453.45
453.92
25530
453.67
454.16
First floor elevations will be established at 2 feet above the revised existing 100 -year elevations pro-
vided in Table 2, since these elevations will still control. The attached maps provided with this letter
show a floodplain delineation based on the ultimate flood elevation provided in Table 2.
Please supplement our previous report with these revised data. Since Mr. Morrison will be reviewing
this report, I have taken the liberty to send him a copy of this letter and maps.
If you have any questions concerning this data, please fell free to call me.
Sincerely,
NATHAN D. MAIER
CONSULTING ENGINEERS, INC.
William L Wallace, P.E.
WLW /slg
Enclosures
cc: Mr. Ronald Morrison