Villages C LOMR-SY 910828I
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I , DON A. TIPTON INC. ,
I CONSULTING ENGINEERS
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- ELM FORK TRINITY RIVER
AND
DENTON CREEK
CITY OF COPPELL
DALLAS COUNTY, TEXAS
FLOODPLAIN RECLAMATION STUDY
VILLAGES OF COPPELL PHASES 3 & 4 3 & 4
REQUEST FOR CONDITIONAL LOMR
PREPARED BY:
DON A. TIPTON, INC.
6330 Belt Line Rd., Suite C
Garland, Texas '75043
214-226-2967
PREPARED FOR:
GRAND/lAKES OF COPP~J. III
8800 N. Central Expwy, #330
Dallas, Texas 75231
214-750-6528
3344.fld/w~7
THIS RECLAMATION STUDY IS BASED ON THE CITY OF COPPELL ADOPTED
REGULATORY FLOODWAY, WHICH IS BASED ON THE PRINCIPLE THAT THE AREA
CHOSEN FOR THE REGULATORY FLOODWAY MUST BE DESIGNED TO CARRY THE
WATERS OF THE BASED FLOOD, WITHOUT INCREASING THE WATER ELEVATION
OF T~_T., E THAN ONE FOOT AT ANY POINT.
ELMFORK TRINITY RIVER
AND
VILLAGES OF COPPELL PHASES 3 & 4
A. INTRODU~TION
The 40.98 acre tract located on the East side of Lake Forest
Drive, South of Deforest Road and Denton Creek, and West of Elm
Fork Trinity River is being developed into single family
residential lots (see Exhibit "B"). This reclamation study
presents the results of the proposed fill along the North property
line adjacent to Deforest Road and the East property line adjacent
to the Elm Fork, as shown on Exhibit "B".
- 4
TABLE OF CONTENTS
A. INTRODUCTION PAGE 4
B. METHODOLOGY 5
- C. WATER SURFACE PROFILES - DENTON CREEK 6
- D. WATER SURFACE PROFILES - ELM FORK 7
E. CONCLUSIONS 8
F. HEC-2 MODELS 9
G. EXHIBITS
~ FORK TRINITY RIVER
AND
- DETOaN CREEK
VILLAGES OF COPPELL PHASES 3 & 4
B. METHODOLOGY
The hydraulic parameters for this project are the same as the
current effective City of Coppell HEC-2 Computer Model for Denton
_ Creek and Elm Fork Trinity River. These models were obtained from
the City Engineering Department Floodplain Management Section. The
Ultimate 2-Year and lO0-Year discharges and starting water surface
elevations were included in this data. The water surface
elevations shown for Denton Creek are Based on the existing water
.... surface elevations of the Elm Fork Trinity River.
VILLAGES OF COPPELL PHASES 3 & 4
C. WATER SURFACE PROFILES- DENTON CREEK
The City of Coppell Floodplain Criteria requires that any new
construction be built using ultimate watershed development to
establish minimum fill and finish floor elevations. The computer
models used in this study utilize this ultimate discharge to
determine the resultant water surface elevations. Following is a
summary table comparing the existing lO0-year and proposed lO0-year
water surface elevations , velocities, and storage volume for FIS
"Q"-iO0 and Ultimate "Q"-IO0.
DENTON CREEX
- FIS ~-100
SUMMARY TABLE
- CROSS WATER SIIRFACE ELEVATION VELOCITIES STORAGE VOLUME
SECTION FIS ..................................................
NUSBER *Q* EXISTIHG PROPOSED EXISTING PROPOSED EXISTING PROPOSED
- 1844020600 452.10 452.10 2.71 I 2.71 0.000.00
..... i;;~;' ...... ~;;;; ...... ~;~ ...... ~;;~; ........ :~;'i ....... i~;; ...... i;;~;~ ......
452.36 452.36 4,12,I 4.12 654.44ti 654.44
2156O
2O6OO
- ' .... :~,o' ~o~oo: ,~:;; ...... :;i:;;'i ....... ::;i'l ....... ::;i ...... ;=;;'I .....
~- 24700 20600 453.46 453,46 3.81 3.81 1054.87 1054.87
25530 20600 453.59 453.59 6.83 6.83 1118.99 1118.99
ULTIMATE
SUlfllARY TABLE
CROSS WATer SURFACE ELEVATION VELOCITIES STORAGE
SECTION ULTIMATE ...........................................................................
NUIIBER 'Q* EXISTING I PROPOSED EXISTING PROPOSED EXISTING PROPOSRD
..... r;;;;' ...... ;;;;; ...... ;;;:;;'i' ..... ;;;;;; ........ ;:;;] ....... ;;;; ........ ;;;;'i ....... ;:;;'
19330 28083 452.50 452.50 2.011 2.01 221.721 221.72
I I I ...................... I
..... :;;~o ~,o,~ ,~.~o ,~.~o, ~.o~I ~.o~I ,~.!~.I .....
781.~6
..... ;;;;; ....... ;;;;;-i ..... ;;;:;; ...... ;;;:;;-~ ....... ;:;;-' ....... ;:;; ..... rr;;:o~l ~.o~
25530
ELM FORK TRINITY RIVER
AND
DENTON CREEK
VILLAGES OF COPPELL PHASES 3 & 4
D. WATER SURFACE PROFILES - ELMFORK
The City of Coppell Floodplain Criteria requires that any new
~.~ construction be built using ultimate watershed development to
establish minimum fill and finish floor elevations. The computer
__ models used in this study utilize this ultimate discharge to
determine the resultant water surface elevations. Following is a
summary table comparing the existing 100-year and proposed 100-year
water surface elevations, velocities, and storage volume for
Ultimate "Q"-iO0.
ELM FORK CREEK
ULTIMATE mQ"-100 SUM]~RY TABLE
CROSS WATER SURFACE ELEVATION VELOCITIES STORAGE VOLUME
SECTION ULTIMATE ...........................................................................
NUMBER "Q" EXISTING PROPOSED EXISTING PROPOSED EXISTING PROPOSED
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100040
55000
447.52 I 447.52 2.39 2.39 1208.00 1208.00
103060 61900 448.88 448.88 3.81 3.81 1603.D0 1603.00
*105500 61900 450.95 450.95 2.44 2.45 1761.00 1761.00
*105500 61900 451,42 451.42 2,31 2.30 iB04.00 1B04.O0
106080 61900 451,92 451.92 4.62 4.61 1853.D0 1853.00
110580 43400 453,43 453.43 1,28 1.28 2673.00 2673.00
110720 43400 453,45 453.45 1,44 1,44 2713.00 2713.00
110750 43400 453,46 453,46 1.44 1.44 2920.00 2920.00
110790 43400 453.39 453,39 1.87 1.87 2728.00 2728.00
*ADDED SECTIONS
ELN FORK TRINITY RIVER
AND
DENTON CREEK
VILLAGES OF COPPELL PHASES 3 & 4
CONCLUSIONS
The 40.98 acre tract known as Villages of Coppell Phases 3 & 4
will be developed into a Planned Development consisting of single
family lots. The fill will be placed on Lots 8 through 46, Block
A, in Villages of Coppell Phase 3 and on Lot 3?, Block A, in
Villages of Coppell Phase 4, as shown on Exhibits "A" & "B". This
report shows that no negative effects are created for properties
upstream, through, or downstream of the development.
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ELM FORK TRINITY RIVER
AND
- DENTON CREEK
VILLAGES OF COPPELL PHASES 3 & 4
F. HEC-2 MODELS
Computer runs are attached that demonstrate compliance with the
City of Coppell criteria as follows:
I. DENTON CREEK
-- A. Existing Conditions
1. 100-Year Floodway Duplication
2. lO0-Year Floodway Existing FEMA
3. 2-Year Ultimate
-~' 4. 100-Year Ultimate
B. Proposed Fill Conditions
1. lO0-Year Floodway Duplication
2. 100-Year Floodway Existing FEMA
3. 2-Year Ultimate
4. lO0-Year Ultimate
C. Multiple Profiles 10, 50, 100, 500
- 1. 100-Year Floodway Duplication
2. 100-Year Floodway Existing FEMA
3. 2-Year Ultimate
4. 100-Year Ultimate
II. ELM FORK
- A. Existing Conditions
1. 2-Year Ultimate
2. lO0-Year Ultimate
3. Standard Project Flood
B. Existing Conditions with Added Sections
1. 2-Year Ultimate
2. 100-Year Ultimate
3. Standard Project Flood.
C. Proposed Fill Conditions
1. 2-Year Ultimate
2. 100-Year Ultimate
3. Standard Project Flood
HEC-2 MODELS
DENTON CREEK
-- EXISTING CONDITIONS
HEC-2 MODELS
DENTON CREEK
-- PROPOSED FILL CONDITIONS
HEC-2 MODELS
MULTIPLE PROFILES 10, 50, 100, 500
HEC-2 MODELS
ELM FORK
EXISTING CONDITIONS
HEC-2 MODELS
EXISTING CONDITIONS WITH ADDED SECTIONS
HEC-2 MODELS
.ELM FORK
-- PROPOSED FILL CONDITIONS
ELM FORK TRINITY RIVER
AND
DENTON CREEK
VILLAGES OF COPPELL PHASES 3 & 4
EXHIBIT "A" VICINITY MAP
EXHIBIT "B" RECLAMATION PLAN
EXHIBIT "C" CROSS SECTIONS