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Villages C P3&4-SY 911230DON A. TIPTON~ INC. CONSULTING ENGINEERS ELM FORK( TRINITY RIVER AND -- DENTON CREEK CITY OF COPPELL DALLAS COUNTY, TEXAS FLOODPLAIN RECLAMATION STUDY VILLAGES OF COPPELL PHASES 3 & 4 REQUEST FOR CONDITIONATIONAL LOMR Pl~:PAR~D BY: DON A. TIPTON~ INC. 6330 Belt Line Rd., Suite C __ Garland, Texas 75043 214-226-2967 PREPARED FOR: GRAND/LAKES OF COPPELL III 8800 N. Central Expwy, #330 _ Dallas, Texas 75231 214-750-6528 3344.fld/wp10 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 THAT FLOOD MORE THAN ONE FOOT AT ANY POINT. TABLE OF CONTENTS A. INTRODUCTION B. METHODOLOGY C. 404 PERMIT LETTER D. WATER SURFACE PROFILES - DENTON CREEK E. WATER SURFACE PROFILES - ELM FORK F. CONCLUSIONS G. HEC-2 MODELS H. EXHIBITS VILLAGES OF COPPELL PHASES 3 & 4 A. INTRODUCTION 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". ELM FORK TRINITY RIVER AND -- DENTON 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 100-Year discharges and starting water surface elevations were included in this data. The water surface elevations shown for Denton Creek are Based onthe existing water -- surface elevations of the Elm Fork Trinity River. -.~ C. 404 PERMIT LETTER DEPARTMENT OF THE ARMY FORT WORTH DISTRICT, CORPS OF ENGINEERS P.O. BOX 17300 FORT WORTH, TEXAS 76102-0300 REPLY TO ATTENTION OF: December 30, 1991 Operations Divis ion Office Operations Branch SUBJECT: Project Number 199100515 Robert Porter Don A.' Tipton, Inc. Consulting Engineers ~ 6330 Belt Line Road, Suite C Garland, Texas 75043 Dear Mr. Porter: Thank you for your correspondence of November 15, 1991, concerning a proposal by Grand Homes to develop a residential subdivision known as th~ Villages of Coppell, Phases 3 & 4, south of Deforest Road and west of Denton Creek in the city.of Coppell, Dallas County, Texas. This project has been assigned Project Number 199100515. Please include the project number in all future correspondence concerning this project. Failure to reference the project number on future correspondence may result in delay. Please note that we previously addressed the area for which this project is proposed as Project Number 198503050. We have reviewed this project in accordance with Section 404 of the Clean Water Act and Section 10 of the Rivers and Harbors Act of 1899. Under Section 404, the U.S. Army Corps of Engineers regulates the discharge of dredged and fill material into waters of the United States, including wetlands. The Corps responsibility under Section 10 is to regulate any work in, or affecting, navigable waters of the United States. Based on your description of the proposed work, and other information available to us, we have determined that this project will not involve any of the above activities. Therefore, it will not require Department of the Army authorization. Thank you for your interest in our nation's water resources. Please continue to check with us prior to initiating construction in, or affecting, waters of the United States. If you have any -2- questions concerning our regulatory program, please contact Mr. Presley Hatcher at the address above or telephone (817)334-3990. Sincerely, Copies Furnished: Ms. Shohre Daneshmand Engineering Department City of Coppell 255 Parkway Boulevard Coppell, Texas 75019 Mr. Rollin MacRae Texas Parks and Wildlife Department 4200 Smith School Road Austin, Texas 78444 Mr. Robert U.S. Fish and Wildlife Service Ecological Services Stadium Centre Building 711 Stadium Drive East, Suite 252 Arlington, Texas 76011 Mr. Norm Thomas U.S. Environmental protection Agency, Region 6 1445 Ross Avenue Dallas, Texas 75202 ELM FORK TRINITY RIVER ._ AND DENTON CREEK VILLAGES OF COPPELL PHASES 3 & 4 D. 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"-100. DENTON CREEK F!S "Q" - 100 SUMMARY TABLE CROSS FIS WATER SURFACE ELEVATION VELOCITIES ' STORAGE VOLUME SECTION "Q' ........................................................................... NUMBER EXISTING PROPOSED EXISTING PROPOSED EXISTING PROPOSED 18440 20600 452.12 , 452.12 2.77 2.77 0.00 0.0D 19930 20600 452.24 452.24 1.93 1.93 192.82 192.82 19930 20600 452.25 452.28 2.82 2.82 389.30 389.30 2~560 20600 452.39 452.39 4.11 4.11 i 633.09 633.09 22370 20600 452.58 452.58 4.51 4.51 721.84 721.84 23800 20600 452.98 452.98 2.54 2.54 845.55 845.55 24700 28600 453.45 453.45 3.81 3.81 928.97 928.97 ULTIMATE 'Q' - 100 SUMMARY TABLE CROSS ULTIMATE WATER SURFACE ELEVATION ! WITH FLOODWAY CHANNEL VELOCITIES STORAGE VOLUME SECTION "Q" .... ' ...................................................................... { ......................... NUMBER EXISTING PROPOSED EXISTING PROPOSED EXISTING PROPOSED EXISTING PROPOSED 18440 23083 452.38 452.38 452.10 i 452.10 2.85 2.85 0.00 0.00 19930 23083 452.51 452.51 452.20 { 452.20 2.07 2.07 203.96 200.85 .................................... I }!!:!g{ }!!:!g !:g} !:![ ' 409.80 1 ................................................................... 663.74 661.52 21560 23083 452.68 452.68 452.40 { 452.40 4.51 4.51 ......................... 22370 23083 452.90 452.90 452.60 452.60 4.94 4.94 755.16 753.02 23800 23083 453.39 453.39 453.00 453.00 i I 453.50 453.50l{ 4.08 4.08 {{ 974.47 972.60 24700 23083 453.91 453.91 ELM FOR TRINITY RIVER DENTON CREEK VILLAGES OF COPPET.L PHASES 3 & 4 E. WATER SURFACE PROFILES - ELM FORK 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 F.I.S. "Q"-100. and Ultimate "Q"-IO0. SUMMARY TABLE - ELM FORK TRINITY RIVER (F.I.S. 'D') CROSS : FIS I WATER SURFACE ELEVATION I CHANNEL VELOCITIES ~ SIORABE VOLUME , SECTION I '~' : ......................... ) ......................... : ......................... -- NUMBER : I EXISTING I PROPOSED I EXISTING I PROPOSED I EXISTING I PROPOSED 100040 : 48600 I 447.06 I 447.06 ~ 2.63 ) 2.63 J 43i6.10: 4316. i0 l 103060 ) 52800 ) 448.45 : 448.45 : 4.67 i 4.67 ~ 5783.B0 : 5783.B0 *i04BBO : 52800 { 449.98 ) 449.98 ~ 4.16 ) 4.16 ) 6238.50 , 6238.00 1 *105000 : 52800 : 450.18 : 450.18 ) 4.00 : 4.01 : 6296.30 ) 6295.70 ,10~00 451.00 451.00 3.51 3.52 6623.90 6622.B0 106080 ~ ~7400 ~ 451.39 I 451,39 ~ 2.93 ) ~.% ~ 6B41.~0 I 68~0,10 110580 : 37400 I 452.53 ) 452.53 : 1.63 I 1.63 I 9495.40 ) 9495.10 110720 I 37400 I 452.55 I 452.55 : 2.11 ) 2.11 I 9612.10 ~ 9611.80 ~ , x ~ ' 4~ ~6 I 452.56 I 2.10 2.10 I 9634.10 ) 9633.90 l 110,50 , v74C0 , .2. - I 110790 : 37400 : 452.50 I 452.50 ) 4,18 I 4.18 : 9654.10 I 9653.90: *ADDED SECTIONS SUMMARY TABLE - ELM FORK TRINITY RIVER (ULTIMATE 'g') CROSS : ULTIMATE ) WATER SURFACE ELEVATION : CHANNEL VELOCITIES I STORAGE VOLUME SECTION : 'g' ) ......................... '-- -- NUMBER : ) EXISTING : PROPOSED : EXISTING I PROPOSED I EXISTINB : PROPOSED e 100040 I 55000 : 447.52 ) 447.52 I 2.67 I 2.67 I 4762.10 : 4762.10 103060 : ~1100 I 440.87 I 448.87 : 4.67 : 4.67 I ~392.00 : 6392.00 *I04880 : 61100 I 450.39 ) 450.39 I 4.35 I 4.35 I 6901.B0 I 6901.10 -- _ ................................. I ) *105000 i 61100 I 450.61 I 450.61 I 4.19 I 4.19 I 6966.10 ) 6966.30 -- *105500 I 61100 ) 451.47 ) 451.47 I 3.62 ~ 3.63 ) 7329.50 I 7328.20 106080 ) 43000 I 451.86 I 451.86 I 2.95 I 2.94 I 7570.90 I 7569.50 110580 I 43000 : 453,01 ) 453.01 I 1.70 ) 1.70 : 10470.30 ) 10469.90 110720 ~ 43000 ; 453.03 : 453.03 ; 2.17 ) 2,17 I 10598,10 : 10597,70 110750 I 43000 I 453.04 I 453.04 I 2.17 : 2.17 : 10622.50 I 10622.10 .... 110790 I 43000 I 452.97 : 452.97 I 4.54 I 4.54 I 10644.30 I 10643.90 *ADDED SECTIONS -- ELM FORK TRINITY RIVER AND _ DENTON CREEK VILLAGES OF COPPELL PHASES 3 & 4 F. 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 37, 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. ELM FORK TRINITY RIVER AND DENTON CREEK VILLAGES OF COPPELL PHASES 3 & 4 G. HEC-2 MODELS Computer runs are attached that demonstrate compliance with the City of Coppell criteria as follows: -- I. DENTON CREEK A. F.I.S. Existing Conditions Duplication 1. 100-Year National Profile -- 2. 100-Year Floodway Existing FEMA 3. 2-Year Ultimate 4. 100-Year Ultimate _ B. Existing Conditions Updated From 1991 City Management Study 1. 100-Year National Profile 2. 100-Year Floodway Existing FEMA -- 3. 2-Year Ultimate 4. 100-Year Ultimate C. Proposed Reclamation Conditions 1. 100-Year Natural Profile 2. 100-Year Floodway 3. 2-Year Ultimate 4. 100-Year Ultimate -- D. Multiple Profiles with Existing Conditions 1. 10-Year FEMA 2. 50-Year FEMA 3. 100-Year FEMA -- 4. 500-Year FEMA E. Multiple Profiles With Existing Conditions Updated From 1991 City Management Study ~ 1. 10-Year FEMA 2. 50-Year FEMA 3. 100-Year FEMA 4. 500-Year FEMA - F. Multiple Profiles With Proposed Reclamation 1. 10-Year FEMA 2. 50-Year FEMA 3. 100-Year FEMA 4. 500-Year FEMA 5. 2-Year Ultimate 6. 100-Year Ultimate II. ELM FORK A. Existing Conditions 1. 2-Year Ultimate 2. 100-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 Reclamation Conditions 1. 2-Year Ultimate 2. 100-Year Ultimate 3. Standard Project Flood D. Multiple Profiles With Existing Conditions 1. 2-Year Ultimate 2. 100-Year Ultimate -- 3. Standard Project Flood E. Multiple Profiles With Added Sections 1. 2-Year Ultimate 2. 100-Year Ultimate 3. Standard Project Flood F. Multiple Profiles With Proposed Reclamation 1. 2-Year Ultimate _ 2. 100-Year Ultimate 3. Standard Project Flood G. Existing Conditions 1. 2,5,10,25,50,100 & 500 Year Ultimate Discharges -- H. Existing Conditions With Added Sections 1. 2,5,10,25,50,100 & 500 Year Ultimate Discharges I. Proposed Reclamation Conditions _ 1. 2,5,10,25,50,100 & 500 Year Ultimate Discharges DENTON CREEK IA. F. I. S. EXISTING CONDITIONS DUPLICATION DENTON CREEK IB. EXI STING CONDITIONS UPDATED FROM 1991 C ITY MANAGEMENT STUDY DENTON CREEK IC. PROPOSED RECLAMAT I ON- DENTON CREEK -- ID. MULTI PLE PROFI LES WITH _ EXISTING CONDITIONS DENTON CREEK IF. MULTIPLE PROFILES WITH PROPOSED RECLAMATION ELM FORK I IA. EXISTING CONDITIONS -- ELM FORK IIB. -- EXISTING CONDITIONS WITH ADDED SECTIONS SECTIONS ELM FORK IIC. PROPOSED .RECLAMATION -- ELM FORK IID . MULTIPLE PROFILES WITH EXISTING CONDITIONS -- ELM FORK IIE. MULTIPLE PROFILES WITH ADDED S'ECTIONS ELM FORK IIF - MULTIPLE PROFILES WITH PROPOSED RECLAMAT I ON G. EXISTING CONDITIONS _ ( ULTIMATE "Q" ) H . EXISTING CONDITIONS WITH ADDED SECTIONS ( ULTIMATE "Q" ) I . PROPOSED ~ RECLAMATION -- CONDITIONS ( ULTIMATE "Q" ) W Z CD F c:) cc 00 Lo 01 tl- cc C> (y) a. 100 YEAR WATER SURFACE 452.12 PROPOSED FILL Lo C) CD 7- CD CD CD CD c\j . 80.00 120.00 160.00 200.00 240.00 280.00 320.00 360.00 400.00 440 . CO 480.00 320,00 560.00 600.00 640.00 680.00 720.00 760.00 800.00 SECTTOf 18 44/11 0 * w Z CD CD CD LU 00 CL 0 Cc 0 a. c:) 01 ol CD 0 100 YEAR WATER SURFACE 452.24 PROPOSED FILL co CD J CD C) CD a - i i <D I CD I I 80.00 120.00 160.00 200. 240.00 280.00 320.00 360.00 400 .00 440.00 480.00 520.00 560.00 600.00 640.00 680 00 720. 760.00 800.00 840.00 (SECTION 19330 *10' co PROPOSED FILL CL 452.12 PROPOSED WALL 1"-50'H 1"-5V o. Lo 6500 6550 SECTION 18440 cD PROPOSED FILL 52.24 V PROPOSED WALL 1"-50'H 1"-5'V k6 v 660 6900 6950 Nt SECTION 19330 CD C) CD 00 00, 0 0 to C:, t CD 1 100 YEAR WATER S SURFACE 452.25 w- CD CD CD CD CD CD c\j '80.00 1 640.00 680.00 720.00 760.00 120:00 160.00 200, 240,00 280. 320.00 360.00 400.00 440.00 4 480.00 5 520.00 5 560.00 600.00 6 SECTION 19930 *10 CD co- 0) CD c:) 1 c 100 YEAR W WATER SURFACE 4 452.39 CD EXHIBIT 1 "C" CD C) C CROSS SEC • I Go �10 co '80.00 C) CD CD 00 O CD CD CD CD C) C) 100 YEAR WATER SURFACE - 448.45 =01111 I mof 160 .00 200.00 240 .00 280.00 320.00 360.00 400 .00 440 .00 480 .00 520.00 560.00 660.00 640 .00 680.00 720,00 7 800.00 $40 .00 880.00 SECTION 103060 *10' I I 920.00 960.00 0 0 4i U) It PROPOSED FILL 0 PROPOSED GABION SLOPE PROTECTION 0 120.00 U) 100 YEAR WATER SURFACE 449.98 0 O '4* 0 SECTION 104880 9 Scale: 1'-50'H I'-5'V r to ---- I Co 160 .00 200 . 00 240 .00 280.00 320 . 00 360-00 40 . 00 4 4'80 . 00 5' * 20 . 00 560 .0 0 600 . 00 640 . 00 680 .00 720.00 760-00 800 . 00 840 . 00 880.00 920 . 00 "t8750.00 8800.00 8850.00 8900.00 8950.00 9000.00 SECTION 104880 10 ADDED SECTION 0 0 t6 U') It 0 ci tr 0 100 YEAR WATER SURFACE - 450.18 U 0 i ci 120.00 160.00 200.00 240.00 280.00 320.00 360.00 400 440 .00 480 .00 520.00 560.00 600.00 64 0.00 680.00 720.00 760.00 800.00 840 .00 880.00 920 . 00 SECTION 105000 *10 ADDED SECTION 100 YEAR WATER SURFACE - 451.00 Kol 0 0 Ui 8tou.uu bbuu.00 8850.00 8900.00 8950.00 9000.00 9050.00 0 0 6 U) O O 0 0 6 v It 0 0 Ui Co It 0 0 Scale: 1*-50'H I'-5'V v 6 120.00 160.00 200.00 240.00 280.00 320.00 360.00 400.00 440 .00 480.00 520.00 560.00 600.00 640.00 680.00 720.00 760.00 800.00 840.00 880.00 920.00 960 - 00 .t 8550-00 8600.00 8650.00 8700.00 8750.00 8 1 800.00 8850.00 SECTION 105500 *10' ADDED SECTION EXHIBIT "C" CROSS SECTIONS WLLA GES OF COPPELL PHA SE 3&4 City Of Coppell , Texas DON A. 'flPTON, INC. CONSUL11NG ENGINEERS 6330 Belt Line Rd. - Suite C Garland, Texas 75043 ELM FORK TRINITY RIVER DESIGN DRA VN DATE SCALE NOTES FILE NO, d. a. t. d. a. t. 1/91 3344 1000-00 1040.00 1680.00 ELM FORK TRINITY RIVER DENTON CREEK VILLAGES OF COPPELL PHASES 3 & 4 _ H. EXHIBITS EXHIBIT "A" VICINITY MAP EXHIBIT "B" RECLAMATION PLAN EXHIBIT "C" CROSS SECTIONS EXHIBIT "D" WATER SURFACE PROFILES -- EXHIBIT "E" CITY LIMITS MAP EXHIBIT "F" FIRM MAP