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Bethel Estates 1-SY010608 Fcderai Ew. crgcncy Managemcnt Agency Floodplain Analysis Report for a Couditionai Letter Of Map Revision ibr a portion of TRIBliTARY G-1 of GRAPE¥1NE CREEK Locatcd in the City o t: Coppell, Dallas Comity, Texas Volmne I of 3 Submitted 'i [~c City of Coppe!l, Texas and the Federal Em~:rgeacy Management Agency Prepared For: Hohncs Builders, Inc. t406 Halsey Way Suite 100 Can'ollmn~ Texas 75007 ~h epared By: .iD LANDES Inc. Civil & Em;ironmental Engiue:.'.rs I 107 E. 1 '~ Street Fort Worth, Texas 76102 .hme, 2001 Federal Emergency Management Agency Floodplain Analysis Report for a Conditional Letter Of Map Revision for a portion of TRIBUTARY G-I of GRAPEVINE CREEK Located in the City of Coppell, Dallas County, Texas Volume I of 3 Submitted To: The City of Coppell, Texas and the Federal Emergency Management Agency Prepared For: The Holmes Builders, lnc. 1406 Halsey Way Suite 100 Carrollton, Texas 75007 Prepared By: JD LANDES Inc. Civil & Environmental Engineers 1107 E. 1 ~ Street Fort Worth, Texas 76102 June, 2001 TABLE OFCONTENTS EXECUTIVE SUMMARY ........................................... 1 INTRODUCTION PURPOSE ................................................... 2 PROJECT LOCATION ......................................... 2 STREAM ANALYSIS HISTORY ................................. 2 RESEARCH and DATA ............................................. 3 METHODOLOGY .................................................. 3 RESULTS ......................................................... 5 CONCLUSIONS .................................................... 7 TABLES Table l:100-Yr Water Surface Elevations "Current Effective" vs "Da~plicate Effective"with Existing Discharges Table 2:100-Yr Encroachmem Water Surface Elevations "Currem Effective" vs "Duplicate Effective"with Existing Discharges Table 3:100-Yr Water Surface Elevations "Current Effective" vs "Corrected Effective"with Existing Discharges Table 3A: 100-Year Channel Velocities "Current Effective" vs "Corrected Effective"with Existing Discharges Table 4:100-Yr Encroachment Water Sm-face Elevations "Current Effective" vs "Corrected Effective"with Existing Discharges Table 5:100-Yr Water Surface Elevations "Corrected Effective" vs "Proposed Improved" with Existing Discharges Table SA: 100-Year Channel Velocities "Corrected Effective" vs "Proposed Improved"with Existing Discharges Table 6:100-Yr Encroachment Water Surface Elevations "Corrected Effective" vs "Proposed lmproved"with Existing Discharges Table 6A: 100-Yr Water Surface Elevations "Corrected Effective" vs "Proposed Improved" with Ultimate Discharges Table 6B: 100-Yr Encroachment Water Surface Elevations "Corrected Effective" vs "Proposed Improved"with Ultimate Discharges Table 7:2-Year Channel Velocities "Corrected Effective" vs "Proposed Improved"with Existing Discharges Table 8: Minimum Finish Floors vs 100-Year Water Surface Elevations "Proposed Improved" with Existing Discharges Table 9: Minimum Finish Floors vs 100-Year Water Surface Elevations "Proposed Improved" with Ultimate Discharges FIGURES Figure 1: Vicinity Map Figure 2: Project Location Map Figure 3: Project Map Figures 4 through 11: "Current Effective" vs "Corrected Effective" Cross-sections Figures 12 through 19: "Corrected Effective" vs "Proposed Improved" Cross-sections Figure 20: Stream Profile: "Current Effective" vs "Corrected Effective" Figure 21: Stream Profile: "Corrected Effective" vs "Proposed Improved" MAPS Map 1: Current FIRM Commtmity Panel Map 2: Goodwin & Marshall, lnc, August 1992 Map 3: "Corrected Effective" Conditions - 100-Year & 500-Year Floodplain Limits Map 4: "Proposed Improved" Conditions - 100-Year & 500-Year Floodplain Limits Map 5: Site Plan - PD 181: Lots 1 & 2 Block I, Bethel Road Estates Map 6: Site Plan ~ PD 176R2: Lots I & 2 Block 1, Bethel Road Estates Phase li VOLUME 2 OF 3 APPENDICES 1 - 5:HEC-2 Output Files APPENDIX 1: "CURRENT EFFECTIVE" CONDITIONS with Existing Discharges 10, 50, 100 and 500-Year Design Storms APPENDIX 2: "CURRENT EFFECTIVE" CONDITIONS with Encroachments and Existing Discharges - 100-Year Design Storm APPENDIX 3: "DUPLICATE EFFECTIVE" CONDITIONS with Existing Disclmrges I 0, 50, 100 AND 500-Year Design Storms APPENDIX 4: "DUPLICATE EFFECTIVE" CONDITIONS with Encroachments and Existing Discharges - 100-Year Design Storm APPENDIX 5: "CORRECTED EFFECTIVE" CONDITIONS with Existing Discharges 10, 50, 100 and 500-Year Design Storms VOLUME 3 OF 3 APPENDICES 6 - 12:HEC-2 Output Files APPENDIX 6: ~CORRECTED EFFECTIVE" CONDITIONS with Encroactunents and Existing Discharges - 100- Year Design Storm APPENDIX 7: "CORRECTED EFFECTIVE" CONDITIONS with Existing Discharge 2-Year Design Storm APPENDIX 8: "CORRECTED EFFECTIVE" CONDITIONS with Encroachments and Ultimate Discharges - 100-Year Design Storm APPENDIX 9: "PROPOSED IMPROVED" CONDITIONS with Existing Discharges 10, 50, 100 and 500-Year Design Storms APPENDIX 10: "PROPOSED IMPROVED" CONDITIONS with Encroachments and Existing Discharges - 100-Year Design Storm APPENDIX 11: "PROPOSED IMPROVED" CONDITIONS with Existing Discharge 2-Year Design Storm APPENDIX 12: "PROPOSED IMPROVED" CONDITIONS with Encroachments and [Yltimate Discharges - 100-Year Design Storm EXECUTIVE SUMMARY This floodplain analysis report was prepared as part of a request for a Conditional Letter of Map Revision for a portion of Tributary G-1 of Grapevine Creek located in the City of Coppell, Dallas County, Texas. This report documents the stream analysis history to date, the research and data provided for the basis of the information provided herein, and the proposed floodplain fill improvements to be located along the southern overbank. The methodologies conducted for the rendering of the report results are demonstrated with regards to the "Current Effective" hydraulic model, as well as, the subsequent "Duplicate", "Corrected" and "Proposed Improved" hydraulic models. The report indicates that significant discrepancies are apparent between the "Current Effective" hydraulic model cross-sections and reach lengths and the existing topography found throughout the project study area. These apparent errors have been revised in a new "Corrected Effective" hydraulic model, from which "Proposed improved" models are constructed and evaluated. The analysis indicates that all of the results are within the regulatory guidelines established by FEMA and the City of Coppell and that a Conditional Letter of Map Revision is warranted for this project. INTRODUCTION PURPOSE The purpose of this floodplain analysis report is to document the proposed development improvements by The Holmes Builders, Inc. along portions of the southern overbank of Tributary G-1 of Grapevine Creek located in the City of Coppell, Dallas County, Texas, in order to obtain a Conditional Letter of Map Revision (CLOMR). The floodplain fill areas will be utilized as the rear yards of two single-family residences on two platted lots. Additionally, this report will more clearly define the floodplain limits along portions of two other platted lots along the southern overbank. PROJECT LOCATION The project is located in the southwest portion of the City of Coppell, Dallas County, Texas, approximately three hundred feet north of Bethel Road and one-quarter of a mile west of Denton Tap Road. See Figure 1: VICINIITMAP. Tributary G-I of Grapevine Creek traverses roughly west to east through the proposed development properties. See Figure 2: PROJECTLOCATION MAP. The project is shown currently on Finn Community Panel 480170 0010 E; see Map 1: ( ~(/RRENT FIRM COMMUNITY t~ANEL. The project area is bounded to the north by Big Cedar Addition, a single-family residential subdivision, to the east by undeveloped agricultural property, to the south by Bethel Road and to the west by Old Coppell Estates, a residential single-family subdivision. The project limits for this study begin at cross-section 340 and end at cross-section 1760. The proposed fill area lies in one distinct section of the southern overbank. See Figure 3: PROJE( :T MAP. STREAM ANALYSIS HISTORY Tributary G-1 of Grapevine Creek was first documented as a flood prone area by FEMA in maps dated March 8, 1974. The current effective FIRM Community Panel 480170 0010 E is dated April 15, 1994. There have been several updates and revisions to the maps over th'ts time period. In 1991, Goodwin and Marshall, Inc. prepared a detailed study of the stream, which was appointed by FEMA as Case No. 91-06-70R. This case study was subsequently approved by FEMA and thereby established the regulatory limits of the existing 100-year floodplain and floodway for Tributary G-1 of Grapevine Creek. The last map revision within the limits of this proposed project area was made in 1992 by Goodwin and Marshall, Inc. on behalf of Matthews Investments Southwest, Inc., as a floodplain reclamation project for the development of Big Cedar Addition, which lies along the northern floodplain. Goodwin and Marshall Inc. utilized both City of Coppell aerial two-foot contoured topography and their own field survey cross-sections as the basis for these studies. The aerial City topography was flown in 1985. At the time of the Goodwin and Marshall, Inc. work. this was considered the best data available, and the best data to date, with which the stream had been studied. A final Letter of Map Revision 1bt the Big Cedar Addition floodplain development work was issued by the FEMA on October 16, 1992. RESEARCH and DATA The original data acquired for development of this analysis was obtained from three principle sources; FEMA by way of the FEMA Library, the City of Coppell and from actual ground surveys prepared in 1999 by [,andes & Associates, Inc. Registered Public Surveyors of Fort Worth, Texas. Portions of the original detailed floodplain analysis report of 1991 and the subsequent request of a Letter of Map Revision report of 1992, both prepared by Goodwin and Marshall, were obtained through the FEIMA Library. This information included plain paper copies of the original HEC-1 watershed analyses, the current effective HEC-2 computer models of the floodplain and floodway, plotted creek cross-sections, stream profiles, and floodplain delineation and watershed area maps. In 1998, the City of Coppell, adopted new city wide aerial topography maps prepared by Dallas Aerial Surveys, Inc. and Teague Nail & Perkins, Inc. This information includes two-/r~)ot interval contours~ spot elevations, roadways, streams, tree lines, buildings, property lines, utility information, etc. This data was obtained from the City in electronic file format. The City of Coppell also maintains on file a fully developed watershed hydraulic analysis report prepared by Albert Halff Associates, Inc. in 1990. This author's report utilizes the 1998 City of Coppell aerial topography and the Albert Halff Associates, Inc. study of fully developed watershed discharges. The 1999 one-foot topography prepared by Landes & Associates, Inc. on the individual platted lots was utilized in conjunction with the City's 1998 aerial topography in the preparation of this report. Both of these sources of topography are based on the National Geodetic Vertical Datum of 1929. METHODOLOGY The project area is intended to sustain the rear yards of four single-family residences. Portions of the southern floodplain of the tributary along Lots I and 2, Block 1 of Bethel Road Estates will require fill in order to accomplish the necessary yard areas. This area lies between cross-sections 560 and 1280. Additionally, the study area was extended to cross-section 1760 in order to refine the hydraulic models along the southern overbanks of the tributary between cross-sections 1450 and 1960. This section of the creek encompasses portions of Lots 1 and 2, Block l of Bethel Road Estates Phase Il. No filling of the floodplain is proposed on these two lots. Both lots 3 provide for proposed swimming pools along the floodplain limits. See Map 5: SITE PI. AN- PD 18I: LOTS 1 & 2, BLOCK l, BETHEL ROAD Iz~S'?'A TES and Map 6: SITE PLAN - PD 176R2: LOTS 1 & 2, BLOCK 1, BETHIfl. ROAD ESTATES PHASI:' 11. This floodplain analysis report utilizes the existing discharges of the "Current Effective" model. Existing 2-year discharges found within this study were extrapolated from the "Current Effective" discharge data. The representative discharges are shown below: "Current Effective" Discharges 2-Year 1340 cfs I O-Year 1860 cfs 50-Year 2735 cfs 100-Year 3140 cfs 500-Year 4210 cfs Ultimate fully developed 100-year discharges of 5150 cfs were taken from the 1990 Albert Hatff Associates, Inc, study for Tributary G-1 of Grapevine Creek. The Army Corps of Engineer's HEC-2 software was utilized for all hydraulic modeling. Both floodplain and floodway electronic "Duplicate Effective" models were created from the "Current Effective"plain paper models obtained from the FEMA Library. Comparative results of these models are shown in Fable l: l O0-Year Water Swface Elevations "Uurrent Effective" vs "Duplicate Effective" ( 'onditions with Existing Discharges and Table 2: lO0-Year Encroachment Water Surface Elevations "Current b7ffOctive, vs "Duplicate I,~ffecttve" Conditions with Existing Discharges. The original worksheet for this analysis was prepared from Goodwin & Marshall's floodplain delineation map. A copy of this map, as prepared by Goodwin & Marshall, is shown as Map 2: (;OODWIN & MARSHALL, Inc. AS-BUlL T IMPROVED ( !ONDIIIONS dated August 1992 of this report. Early in the analysis of this study data discrepancies occurred between the "Current Effective" cross-section elevations and those found at the same cross-section locations derived from the City. of Coppell aerial topography and the field topography of Landes & Associates, Inc. These discrepancies ranged from one to two feet, or more in some areas. At the same time, the discrepancies between the City topography and the Landes & Associates, Inc. topography were minimal and well within the tolerances expected in comparison between two-foot aerial data and field surveyed one-foot contour data. After much investigation and consideration, and after finding no thult with the newer City topography or the Landes & Associates, Inc. topography, the author elected to utilize this data for the extent of this analysis. See Figures 4 through l ]: "Current l~fl_/bctive" vs "Corrected b~ffbclive" ('ross-Sections. Additional discrepancies arose between the "Current Effective" model data and the new field surveys and the City topography with regard to the length of the channel reach through the project limits. The current effective hydraulic model indicates that this total reach length from cross-section 340 to crosss-section 1960 is 1620 feet. The Landes & Associates, Inc. detailed field surveys and the City of Coppell topography indicate that this total reach length is 1551 feet. The reach length discrepancies are shown below: Reach Length Current Effective Corrected Effective Difference (Feet) (Feet) (Feet) 1960to 1760 200 207 7 1760to 1450 310 259 -51 1450 to 1280 170 180 10 1280to 1120 160 158 -2 1120 to 945 175 159 -16 945 to 770 175 167 -8 770 to 560 210 211 1 560 to 340 220 210 -10 Total Length 1620 1551 -69 Fifty-one feet of error is clearly shown between cross-sections 1760 and 1450 of the current effective model. See Map 2 at 1"=100' scale. For the purposes of this report, the author has again utilized the newer data obtained from the 1998 City topography and the 1999 field surveys. Both areas of discrepancies have been addressed and revised. The "Corrected Effective" cross- sections were revised based upon the "Current Effective" horizontal locations, while maintaining the same stream centerline station at each cross-section. Additionally, the"Current Effective" encroachment stations were utilized at each cross-section to maintain the horizontal integrity and width of the current floodway along the platted lots of Big Cedar Addition. The results are shown in the "Corrected Effective" hydraulic models. See Figure 20 for water surface elevation comparisons between the "Current Effective" and "Corrected Effective" models. A detailed grading plan was developed for Lots I and 2, Block I of Bethel Road Estates. See MAP 5: SITE PIMN - PD 181: LOI~' I & 2, BLOCK I, BEI'HEL ROAD ESTATES. This grading plan is also shown on Map 4: "?RPOSED IMI'ROVEI)" ( 7ONDITIONS- IO0-YEAR & 500- YEAR t~LOOI)t'LAIN LIMITS. The grading plan was utilized as the basis for the proposed fill areas between cross-sections 340 and 1280, and this data was incorporated into the "Proposed Improved" hydraulic models. NO new grading was proposed for Lots 1 and 2, Block 1 of Bethel Road Estates Phase II within the floodplain limits. See Fi,eures 12 thro~t,gh 19: "Corrected l~'ective" vs "?roposed Improved" ('roxs-Section,~ for comparisons. RES[ILTS This floodplain analysis resulted in a "Corrected Effective" model which varied from the "Current Effective" model. The resulting differences are directly attributable to the discrepancies found in the cross-sections and the reach lengths. The cross sectional differences are shown in Figures 4 through 11. The resulting 100-Year water surface elevation comparisons vary between -1.50 and 1.86 feet, as shown in Table 3: lO0-Year Water SurJace Elevations "Current FJfective" vs "Corrected b~fi_~ctive" Conditions with Existing Discharges. The table shows water surface reductions from cross-section 340 to cross-section 1280, with the exception of a 0.40 feet increase at cross-section 560. Water surface increases begin at cross-section 1450 and end at 3125. The increases result from the reduced corrected cross-sectional areas and reduced reach lengths. The "Corrected Effective" model shows similar reductions and increases at the same cross-sections for the encroachment run. These results are shown in Table 4: lO0- Year Encroachment Water Surface Elevations "(?urrent I~ffective" vs "(~orrected EJ]~ctive" ( 'onditions with Existing Discharges. The largest increase is 1.43 feet, which occurs at cross- section 1960. 7~ble 3A: ]O0-Year Channel Velocities "('urrent Effkctive" vs "Corrected ]:.ff~.,cttve" Conditions with Exisling Discharges indicates the comparative velocity differences between the "Current Effective" and the "Corrected Effective". These values range from -5.48 fps to 4.13 fps. Map 3: "(~ORRE(~TED I';I,'t~Z'CTIVE'' CONDITIONS- IO0-YEAR & 500-YEAR FLOODI'LAIN L1M1Zg, shows the corrected 100-year and 500-year floodplain delineations. See Figures 12 through 19: "Corrected Effective" vs "Proposed Improved" Cross-Sections. The "Proposed Improved" models were then compared against the "Corrected Effective" models. The analysis indicated that the proposed fill along the southern overbank between cross- sections 560 and 1280, had no impact on the "Corrected Effective" conditions. No 100-Year water surface elevation increases were generated by the "Proposed Improved" conditions for either the floodplain or floodway models. The ultimate fully developed 100-Year discharge model accounted for 0.02 feet water surface elevation increases at cross-sections 770, 945 and 1120 and 0.01 feet increases at cross-sections 1280, 1450 and 1760. The floodway encroachment run with ultimate discharges resulted in no water surthce elevation increases. See Tables 6A and 6B. There were no increases in 100-Year channel velocities between the "Corrected Effective" and Proposed Improved" models. Comparative results between the "Corrected Effective" and "Proposed Improved" 2-Year channel velocities resulted in a 002 fps increase at cross-section 1960 and a 0.01 fps increase at cross-section 2615. Results are shown in Tables 5, 5A, 6 and 7. The minimum finish floor elevations for the four platted lots have been previously established. This report documents, according to City policy, that these minimum finish floor elevations are at least 2.0 feet above the 100-Year "Proposed Improved" conditions with existing discharges and at least 1.0 feet above the 100-Year "Proposed Improved" conditions with ultimate discharges. See Tables 8 and 9. This study also indicates that the proposed swimming pool locations of Lots 1 and 2, Block 1 of Bethel Road Estates Phase I1, lie outside the limits of 100- Year floodplain under the "Corrected Effective" and "Proposed Improved" conditions. "Current Effective" vs "Corrected Effective" and "Corrected Effective" vs "Proposed Improved"stream profiles are shown in Figures 20 and 21. The 100-year and 500-year floodplain delineations for the "Proposed Improved" conditions are shown on Map 4: "PROPOSED IMPRO VEI) " CONDITIONS - I O0- YI:~R & 500-YEAR FI,OODt'I,AIN LIMITS. Complete HEC- 2 hydraulic output files of the Current, Duplicate, Corrected and Proposed lmproved models can 6 be found in Appendices 1 through 12 of this report. CONCLUSIONS This floodplain analysis report concludes that the present "Current Effective" model does not accurately reflect the existing conditions found along the study area of Tributary G-1 of Grapevine Creek. The "Corrected Effective" models contained within this report have been completed to reflect more accurately the actual existing conditions of the creek along the study area from cross-section 340 to 1760. The subsequent "Proposed Improved" models document the proposed floodplain fill areas and indicate that all results are within the regulatory guidelines established by FEMA and the City of Coppell. This report therefore documents that a Conditional Letter of Map Revision is warranted for this project. 7 TABLES 'FABLE 1: 100-YEAR WATER SURFACE ELEVATIONS - "CURRENT EFFECTIVE" vs "DUPLICATE EFFECTIVE" CONDITIONS With Existing Discharges TABLE 2: 100-YEAR ENCROACHMENT WATER SURFACE ELEVATIONS - "CURRENT EFFECTIVE" vs "DUPLICATE EFFECTIVE" CONDITIONS With Existing Discharges TABLE 3: 100-YEAR WATER SURFACE ELEVATIONS - "CURRENT EFFECTIVE" vs "CORRECTED EFFECTIVE" CONDITIONS With Existing Discharges TABLE 3A: 100-YEAR CHANNEL VELOCITIES - "CURRENT EFFECTIVE" vs "CORRECTED EFFECTIVE" CONDITIONS With Existing Discharges TABLE 4: 100-YEAR ENCROACHMENT WATER SURFACE ELEVATIONS - "CURRENT EFFECTIVE" vs "CORRECTED EFFECTIVE" CONDITIONS With Existing Discharges TABLE 5: 100-YEAR WATER SURFACE ELEVATIONS - "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Existing Discharges TABLE 5A: 100-YEAR CHANNEL VELOCITIES - "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Existing Discharges TABLE 6: 100-YEAR ENCROACHMENT WATER SURFACE ELEVATIONS - ~'CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Existing Discharges TABLE 6A: 100-YEAR WATER SURFACE ELEVATIONS - "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Ultimate Discharges TABLE 6B: IO0-YEAR ENCROACHMENT WATER SURFACE ELEVATIONS - "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Ultimate Discharges TABLE 7: 2-YEAR CHANNEL VELOCITIES - "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Exist'mg Discharges TABLE 8: MINIMUM FINISH FLOOR vs 100-YEAR WATER SURFACE ELEVATIONS - "PROPOSED IMPROVED" CONDITIONS with Existing Discharges TABLE 9: MINIMUM FINISH FLOOR vs 100-YEAR WATER SURFACE ELEVATIONS - "PROPOSED IMPROVED" CONDITIONS with Ultimate Discharges TABLE 1 .' 100-YEAR WATER SURFACE ELEVATIONS "CURRENT EFFECTIVE" vs "DUPLICATE EFFECTIVE" CONDITIONS With Existing Discharges CROSS CURRENT DUPLICATE DIFFERENCE SECTION EFFECTIVE EFFECTIVE (FEET) (NGVD) (NGVD) 120 484.38 484.38 0.00 220 484.75 484.75 0.00 230 483.61 483.61 0.00 290 487.29 487.29 0.00 340 489.81 489.81 0.00 560 489.85 489.85 0.00 770 493.58 493.58 0.00 945 493.72 493.72 0.00 1120 493.88 493.88 0.00 1280 493.78 493.78 0.00 1450 494.31 494.31 0.00 1760 495.10 495.10 0.00 1960 494.56 494.56 0.00 2135 496.45 496.45 0.00 2615 497.23 497.23 0.00 3125 499.50 499.50 0.00 3515 501.33 501.33 0.00 TABLE 2: 100-YEAR ENCROACHMENT WATER SURFACE ELEVATIONS "CURRENT EFFECTIVE" vs "DUPLICATE EFFECTIVE" CONDITIONS With Existing Discharges CROSS CURRENT DUPLICATE DIFFERENCE SECTION EFFECTIVE EFFECTIVE (FEET) (NGVD) (NGVD) 120 484.38 484.38 0.00 220 484.75 484.75 0.00 230 483.61 483.61 0.00 290 487.29 487.29 0.00 340 489.72 489.78 *0.06 560 489.90 489.90 0.00 770 493.59 493.59 0.00 945 493.75 493.75 0.00 1120 494.03 494.03 0.00 1280 493.84 493.84 0.00 1450 494.81 49481 0.00 1760 495.90 495.90 0.00 1960 495.46 495.46 0.00 2135 497.50 497.50 0.00 2615 498.00 498.00 0.00 3125 499.66 499.66 0.00 3515 501.64 501.64 0.00 * DIFFERENCE CONSIDERED A SOFTWARE ANOMALY TABLE 3: 100-YEAR WATER SURFACE ELEVATIONS "CURRENT EFFECTIVE" vs "CORRECTED EFFECTIVE" CONDITIONS With Existing Discharges CROSS CURRENT CORRECTED DIFFERENCE SECTION EFFECTIVE EFFECTIVE (FEET) (NGVD) (NGVD) 120 484.38 484.38 0.00 220 484.75 484.75 0.00 230 483.61 483.61 0.00 290 487.29 487.29 0,00 340 489,81 489.73 -0.08 560 489.85 490.25 0.40 770 493.58 492.08 -1.50 945 493.72 492.58 -1.14 1120 493.88 492.55 -1.33 1280 493.78 493.70 -0.08 1450 494.31 494.92 0.61 1760 495.10 496.29 1.19 1960 494.56 496.42 1.86 2135 496.45 497.20 0.75 2615 497.23 497.61 0.38 3125 499.50 499.53 0.03 3515 501.33 501.33 0.00 TABLE 3A: 100-YEAR CHANNEL VELOCITIES "CURRENT EFFECTIVE" vs "CORRECTED EFFECTIVE" CONDITIONS With Existing Discharges CROSS CURRENT CORRECTED DIFFERENCE SECTION EFFECTIVE EFFECTIVE (FT/SEC) (FT/SEC) (FT/SEC) 120 7.82 7.82 0.00 220 10.92 10.92 0.00 230 16.95 16.95 0.00 290 11.96 11.96 0.00 340 5.00 5.64 0.64 560 14.24 8.76 -5.48 770 3.20 4.80 1.60 945 3.17 3.22 0.05 1120 2.84 6.97 4.13 1280 5.74 7.24 1.50 1450 5.76 7.62 1.86 1760 2.76 3.87 1.11 1960 9.64 6.48 -3.16 2135 2.95 2.49 -0.46 2615 6.20 5.77 -0.43 3125 7.12 7.06 -0.06 3515 7.35 7.35 0.00 TABLE 4: 100-YEAR ENCROACHMENT WATER SURFACE ELEVATIONS "CURRENT EFFECTIVE" vs "CORRECTED EFFECTIVE" CONDITIONS With Existing Discharges CROSS CURRENT CORRECTED DIFFERENCE SECTION EFFECTIVE EFFECTIVE (FEET) (NGVD) (NGVD) 120 484.38 484.38 0.00 220 48475 484.75 0.00 230 483.61 483.61 0.00 290 487.29 487.29 0.00 340 489.72 489.58 -0.14 560 489.90 490.22 0.32 770 493.59 492.05 -1.54 945 493.75 492.58 -1.17 1120 494.03 492.52 -1.51 1280 493.84 493.97 0.13 1450 494.81 495.53 0.72 1760 495.90 496.89 0.99 1960 495.46 496.89 1.43 2135 497.50 498.33 0.83 2615 498.00 498.65 0.65 3125 499.66 499.88 0.22 3515 501.64 501.68 0.04 TABLE 5: 100-YEAR WATER SURFACE ELEVATIONS "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Existing Discharges CROSS CORRECTED PROPOSED DIFFERENCE SECTION EFFECTIVE IMPROVED (FEET) (NGVD) (NGVD) 120 484.38 484.38 0.00 220 484.75 484.75 0.00 230 483.61 483.61 0.00 290 487.29 487.29 0.00 340 489.73 489.73 0.00 560 490.25 490.25 0.00 770 492.08 492.08 0.00 945 492.58 492.58 0.00 1120 492.55 492.55 0.00 1280 493~70 493.70 0.00 1450 494.92 494.92 0.00 1760 496.29 496.29 0.00 1960 496.42 496.42 0.00 2135 497.20 497.20 0.00 2615 497.61 497.61 0.00 3125 499.53 499.53 0.00 3515 501.33 501.33 0.00 TABLE 5A: 100-YEAR CHANNEL VELOCITIES "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Existing Discharges CROSS CORRECTED PROPOSED DIFFERENCE SECTION EFFECTIVE IMPROVED (FT/SEC) (FT/SEC) (FT/SEC) 120 7.82 7.82 0.00 220 10.92 10.92 0.00 230 16.95 16.95 0.00 290 11.96 11.96 0.00 340 5.64 5.64 0.00 560 8.76 8.76 0.00 770 4.80 4.80 0.00 945 3.22 3.22 0.00 1120 6.97 6.97 0.00 1280 7.24 7.24 0.00 1450 7.62 7.62 0.00 1760 3.87 3.87 0.00 1960 6.48 6.48 0.00 2135 2.49 2.49 0.00 2615 5.77 5.77 0.00 3125 7.06 7.06 0.00 3515 7.35 7.35 0.00 TABLE 6: 100-YEAR ENCROACHMENT WATER SURFACE ELEVATIONS "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED' CONDITIONS With Existing Discharges CROSS CORRECTED PROPOSED DIFFERENCE SECTION EFFECTIVE IMPROVED (FEET) (NGVD) (NGVD) 120 484.38 484.38 0.00 220 484.75 484.75 0.00 230 483.61 483.61 0.00 290 487.29 487.29 0.00 340 489.58 489.58 0.00 560 490.22 490.22 0.00 770 492.05 492.05 0.00 945 492.58 492.58 0.00 1120 492.52 492.52 0.00 1280 493.97 493.97 0.00 1450 495.53 495.53 0.00 1760 496.89 496.89 0.00 1960 49&89 496.87 -0.02 2135 498.33 498.31 -0.02 2615 498.65 498.64 -0.01 3125 499.88 499.87 -O.O1 3515 501.68 501.68 0.00 TABLE 6A: 100-YEAR WATER SURFACE ELEVATIONS "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Ultimate Discharges CROSS CORRECTED PROPOSED DIFFERENCE SECTION EFFECTIVE IMPROVED (FEET) (NGVD) (NGVD) 120 487.13 487.13 0.00 220 487.44 487.44 0.00 230 487.08 487.08 0.00 290 492.88 492.88 0.00 340 492.86 492.86 0.00 560 493.07 493.05 -0.02 770 494.90 494.92 0.02 945 495.33 495.35 0.02 1120 495.19 495.21 0.02 1280 495.96 495.97 0.01 1450 497.02 497.03 0.01 1760 498.72 498.73 0.01 1960 498.88 498.88 0.00 2135 499.46 499A5 -0.01 2615 499.58 499.58 0.00 3125 501.30 501.30 0.00 3515 502.82 502.82 0.00 TABLE 6B: 100-YEAR ENCROACHMENT WATER SURFACE ELEVATIONS "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Ultimate Discharges CROSS CORRECTED PROPOSED DIFFERENCE SECTION EFFECTIVE IMPROVED (FEET) (NGVD) (NGVD) 120 487.14 487.14 0.00 220 487.45 487.45 0.00 230 487.08 487.08 0.00 290 492.60 492.60 0.00 340 492.60 492.60 0.00 560 493.21 493,21 0.00 770 495.09 495.09 0.00 945 495.53 495.53 0.00 1120 495.15 495.15 0.00 1280 496.54 496.54 0.00 1450 497.85 497.85 0.00 1760 499.79 499.79 0.00 1960 499.46 499.43 -0.03 2135 501.70 501.68 4).02 2615 501.89 501.88 -0.01 3125 502.73 502.72 -0.01 3515 504.12 504.11 -0.01 TABLE 7: 2-YEAR CHANNEL VELOCITIES "CORRECTED EFFECTIVE" vs "PROPOSED IMPROVED" CONDITIONS With Existing Discharges CROSS CORRECTED PROPOSED DIFFERENCE SECTION EFFECTIVE IMPROVED (FT/SEC) (FT/SEC) (FT/SEC) 120 5.97 5.97 0.00 220 7.69 7.69 0.00 230 9.89 9.89 0.00 290 9.35 9.35 0.00 340 10,17 10.17 0.00 560 7.11 7.11 0.00 770 4.24 4.24 0.00 945 2,93 2~93 0,00 1120 6.29 6.29 0.00 1280 5.96 5.96 0.00 1450 5.42 5.42 0.00 1760 3.59 3.59 0.00 1960 5.36 5.38 0.02 2135 2.45 2.45 0.00 2615 4.20 4.21 0.01 3125 6.06 6.06 0.00 3515 5.40 5.40 0.00 TABLE 8: MINIMUM FINISH FLOORS vs 100-YEAR WATER SURFACE ELEVATIONS "PROPOSED IMPROVED" CONDITIONS With Existing Discharges PLATTED MINIMUM FINISH 100-YEAR W.S. FREEBOARD LOT FLOOR ELEVATION (Feet) Lot 2, Block 1 497.6 492.55 5.05 Bethel Rd. Estates Lot 1, Block 1 497.6 493.70 3.90 Bethel Rd. Estates Lot 2, Block 1 Bethel Rd. Estates Phase lI Lot 1, Block 1 Bethel Rd. Estates Phase 11 500.0 496.29 3.71 500.0 496.29 3.71 TABLE 9: MINIMUM FINISH FLOORS vs 100-YEAR WATER SURFACE ELEVATIONS "PROPOSED IMPROVED" CONDITIONS With Ultimate Discharges PLATTED MINIMUM FINISH 100-YEAR W.S. FREEBOARD LOT FLOOR ELEVATION (Feet) Lot 2, Block 1 497.6 495.21 2.39 Bethel Rd. Estates Lot 1, Block I 497.6 495.97 1.63 Bethel Rd. Estates Lot 2, Block 1 Bethel Rd. Estates Phase 11 Lot 1, Block 1 Bethel Rd Estates Phase II 500.0 498.73 1.27 500.0 498.73 1.27 FIG URES FIGURE 1 :Vicimty Map FIGURE 2: Project Location Map FIGURE 3: Project Map FIGURE 4: Cross-Section 340: "Current Effective" vs "Corrected Effective" FIGURE 5: Cross-Section 560: "Current Effective" vs "Corrected Effective" FIGURE 6: Cross-Section 770: "Current Effective" vs "Corrected Effective" FIGURE 7: Cross-Section 945: "Current Effective" vs "Corrected Effective" FIGURE 8: Cross-Section 1120: "Current Effective" vs "Corrected Effective" FIGURE 9: Cross-Section 1280: "Current Effective" vs "Corrected Effective" FIGURE 10: Cross-Section 1450: "Current Effective" vs "Corrected Effective" FIGURE 11: Cross-Section 1760: "Current Effective" vs "Corrected Effective" FIGURE 12: Cross-Section 340: "Corrected Effective" vs "Proposed Improved" FIGURE 13: Cross-Section 560: "Corrected Effective" vs "Proposed Improved" FIGURE 14: Cross-Section 770: "Corrected Effective" vs "Proposed Improved" FIGURE 15: Cross-Section 945: "Corrected Effective" vs "Proposed Improved" FIGURE 16: Cross-Section 1120: "Corrected Effective" vs "Proposed Improved" FIGURE 17: Cross-Section 1280: "Corrected Effective" vs "Proposed Improved" FIGURE 18: Cross-Section 1450: "Corrected Effective" vs "Proposed Improved" FIGURE 19: Cross-Section 1760: "Corrected Effective" vs "Proposed Improved" FIGURE 20: Stream Profile: "Current Effective" vs "Corrected Effective" FIGURE 21: Stream Profile: "Corrected Effective" vs "Proposed Improved" IFigure 11 VICINITY MAP1 iz· · o <~ 0 J 773ddOD X 0 c- O CD , \ U C (~-j) g q~ C n Z 0 c- (:~ -I) UOI~DAal3 C 0 Z Z 0 © 0~ I I z 0 llb 0 o U 0 I i ! I I 0 0 0 Z ((]ADN) ±ZlS]_~ NI NOI/VA]-I] 0 0 0 \ \ - ~:7-~ .................. ~ ........ ~, ' i \~ \ [9g 5 ......................... ' ~ I ............. i_~_ ........................... Cig ~\ ~ \ 7YgB-F - __L¥ ...... ~ ................... .......... . , / .......... ==~- .............. =m- T7gz-F ........ = . ---[)g~] ...... ]] ....... i~ .......... ~' ...... 4, - ~T 2- .... 7--2 T7 ...... 55]Z2] .......... ]Z]]] 2 - .............. I ' ' ~ ~ ...................... ~ ................ O~Z ......... ............ ______---~ ..... -- - ..... -- .... .................................................... 09g ............. ,~  ' ~ '-]-S ] .... ZZS]] ] ....... Z 27]7"~:: ........................... .................................... ......... . ........................... Og~ (GAON) 133J NI NOIZVA3]3 (GAON) J_qq4 NI NOIJ_VA393 0 0 -~¢-~-~--~- ............. , \ ~' ~, ~ ~ ....... ~ .................. ~ , ~ ................................... 7~g~f r -¢-~F~ ~-~- .................... ~- ............. ~J4w .... ~ 0 , ,, i .......... ! ................ t ~ .......... ........................... ~ ..... ~--1 ~ .......... O~C -~-~ j 0~ , I (GAON) ~33J NI NOI~VA333 MAPS MAP 1: Current FIRM Community Panel MAP 2: Goodwin & Marshall, Inc. As-Built Conditions, dated 1992 MAP 3: "Corrected Effective" Conditions - 100-Year & 500-Year Floodplain Limits MAP 4: "Proposed Improved" Conditions - 100-Year & 500-Year Floodplain Limits MAP 5: Site Plan - PD 181: Lots I & 2, Block 1, Bethel Road Estates MAP 6: Site Plan: - PD 176R2: Lots 1 & 2, Block 1, Bethel Road Estates Phase II q it rn', G 1 i I - -- - - - - - - Ljj 508- Lj—j LFLJ LILI 1 11 LL j kI IZ - ------- -- -- ------ R I W II I t U) I I L t I EL D O DILLARD LANE � N W \c Z W 605 0— ------------------ -------------- ___ -- W 0 50 100 200 600 - - - - --------- SCALE' 1"z 100 J -4 t'7 w CL t 0. 0 492 IF 494 -456 I/11111 It �AAAP I it sw t 6Ap tIMITS OF; IWAIAAJA A52- -Toay MUMS Z-35 TRIBUTARY G-71- -A34 o __A86 190V to 0 '17 3515 ce) It �,Lj 504--__ r --- saF I A f lit \ % I I I -­, I, - '\ % /1,1 kk% if I I .... ... ...... C3 T LLDI A f V i 'Im - 0 NNNI A ""V Z.N If I V// I '49e - If ------ E-1 5 0, C3 r— — — — — — — — — - - Z z 0'LJ 508- IF ;j ----------- 0 0 a! / /!! 1450 0 • C3 510, --602-- _­.ttj_ - 1 1: 1 - I I I , I I I I -------- - -476- ------------ -1120 .945\ 770 IN, -.7%Z z---- - N BETHEL RO LZ A C�; C14 C0 7 -_" -512, ---------- IF F77771 n, f f 43 504 0 506 ------------- if NOTE: Topographic information based on interpolation of field surveyed cress- sections and City of Coppell two foot contour interval topographic maps. LEGEND 1280 Cross-section Location 500 yr. Existing Conditions Floodplain Delineation ("As MCI) 100 yr. Existing Conditions Floodplain Delineation ("As Built-) Reclamation Area NOTE.Floodway for Tributary G-1 shall remain the same as shown for Existing Conditions. (See original flood study) GOODWIN z , U\T A is U z MICHAEL BAKER, III t., INC REcEIVEB TRIBUTARY G-1 OF GRAPEVINE CREEK SEP " 193rJ2 COPPEU, TEXAS ALEXANDRIA, VIR 'INtA "AS BLrffir IMPROVED CONDr--r-I Job No 9271 DOW AUGUST 19W !Sme V 10a J1..Q S H E E TtC 21 , , , , , N N 11, iZ LINE BLOCK HE L ROAD STATES P 499.5iX TRIBUTARY G -1 OF GRAPEVINE CREEK COPPELL, DALLAS COUNTY, TEXAS 111 I 1�U WENDY WEBSTE 5 X 495.7 fir LO�K BE EL R DES F4 TES 770`\ ..•���ti'<�8 2� 1107 E. 1st Street s 411 MAP 3 . Fort Worth, Texas 76102 =. *t 817 870 -1220 CORRECTED EFFECTIVE CONDITIONS JV,ANDES JUs11N D. LANDES 817 870 -1292 Fax � 100 -Year & 500 -Year Flood lain Limits CMLJENVIRONMENTAL `1t�� ` GIST$ P ENGINEERING t��� �' -T " Project No. J00014 File J00014 CorrectedEffective.dw J M 484 LEGEND CL STREAM r ACKNOWLEDGMENTS: REVISIONS The existing topography shown was obtained from the following sources. The two -foot interval contours are 1998 City of Coppell topography as prepared by Teague Nail & Perkins and Dallas Aerial Surveys, Inc. The one -foot interval contours were prepared in 1999 by Landes & Associates, Inc. Registered Public Surveyors from actual ground surveys. 492.2 X HOR. SCALE: JUNE 1' =30' 2001 VERTICAL SCALE: SHEET NONE 1OF1 I Q 13 12 ........... . . ... lb rri itI 10 PROP. RESIDENCE 4-,FIN. FLOOR 500.0 I I - PROP, RESIDENCE MIN. FIN. FLO .0 14 UVA rid 11 11 9 600�0000# 0060, 6 01 500 3 7 OJCO/ LAY MIN. FIN. FLOOR 497.6 PROP. BUILDING PAD PROP. FINISH FLOOR 500.5 A 4 5 N 3 LEGEND E>0 CROSS-SECTION CL STREAM EXISTING CONTOUR PROPOSED CONTOUR PROPOSED GRADE 497.6 PROPOSED 500-YEAR FLOODPLAIN LIMITS PROPOSED 100-YEAR FLOODPLAIN LIMITS \\\\A\\Ik\ 11 499 X497.4 497---- K BLOIC 498. 1 1 2 500 496 480 50 498. 9$ ETHEL ROAD ESTATES P II sa T I B Ic K I LO 2 94 I LOT 11 LOT 2 WEN D I W TER THE OL4 S TA 499.51X, :�Iijflj! or uo 0 106 T a T HE — R®AI� - W4PA ACKNOWLEDGMENTS: REVISIONS: 1107 E. 1st Street f I The existing topography shown was obtained from the following sources. The TRIBUTARYG-1 M AP 4: Fort Worth, Texas 76102 1f two-foot interval contours are 1998 City of Coppell topography as prepared by 817 870-1220 Teague Nall & Perkins and Dallas Aerial Surveys, Inc. The one-foot interval OF PROPOSED IMPROVED CONDITIONS JVjANDES "I contours were prepared in 1999 by Landes & Associates, Inc. Registered Public R-17 870-1292 Fax JUSTIN D. LANDES Surveyors from actual ground surveys. GRAPEVINE CREEK 68081 100-Year & 500-Year Floodplain Limits CrVIL/ENVIRONMENTAL COPPELL, DALLAS COUNTY, TEXAS ENGUMUUNG Frio' t No. J00014 File J00014 Pro pose4lmE roved ,dwg 492.2 X HOR. SCALE: JUNE 1 1 P _30 2001 VERTICAL SCALE: SHEET NONE 1 OF1 I Ic = 74 °11'23" CH = N04 °23'01 "E x R — 50.00 ) BENCHMARK 1: ELEVATION 500.13 RAILROAD SPIKE SET IN POWER POLE IN THE NORTH ROW LINE OF BETHEL ROAD NEAR SOUTHEAST CORNER OF WENDY WEBSTER TRACT. BENCHMARK 2: ELEVATION 513.24 CITY OF COPPELL GPS MONUMENT, BEING A BRASS DISK IN PROTECTED COVER IN NORTH SIDE OF SOUTHWESTERN BELTLINE AND BELTLINE ROAD. L = 64.74' LEGEND CL — 60.31 ' EXISTING CONTOUR i HEARTHSTONE LANE _ N04 °36'23 "E ! 73.04' 25' BLDG LINE OLD Co I I ESTA T 0 zo i 9 ITV �F— 9 c� F� 18 j i ! Csi w I I ! i , 7 eft zi REST TING i HOR. SCALE: I t n DENCE I 1 1) = 3`0' � I I i J Lo I BLOCK 1 to Lot Block tj VERTICAL SCALE: N 0.4711 AC. Estates i NONE ! O N ' 2!. ♦ w i i j NO °3 '23 "E 264, 77' i 2 "oak O 1 GR 7 I 11 1 r--- -. �_Ce gBLDG INE 10 "o v 2 "Pecan pe 6" 12 "ce Qce s . ° ti a /� ® e 00 n 1 !! pecan Ce Lot 1 lock 1 Bethel Road Estates Phase II 0.529 AC. r ASSN 261' WAGE HEIGHT 8' BLDG LINE e ESIDE CE L t 2 Block -I ce B hel Road Mates Phase It \ 0.5114 AC. TRIP iW a: S01 000'47 "W 241.0 WENDY WEBSTER ZONING C I I NEAREST DRIVEWAY BETHEL ROAD ESTATES FLOOD STUDY COPPELL, TEXAS 16" © 14 oak EXISTING TREE TO REMAIN 6 " EXISTING TREE TO BE REMOVED pecan EXISTING 100 -YEAR FLOOOPLAIN \ EXISTING 100 -YEAR FLOODWAY PROPOSED FRONT FENCE \ \ OLD COPPELL ESTATES �S�_,BLDG \-Il \\ ZONING SF 9 LOT AREAS \� \\ r BETHEL ROAD ESTATES PHASE 11 (Formerly McMillan Estates; one lot at 1.7281 Acres) EXISTING \ \ LOT 1 BLOCK 1: RESIDENCE \ 0.5292 ACRES Lot 15R Block 1 \ I I Old Coppell Estates \ ''\ 14 LOT 2 BLOCK 1: 0.3575 AC. A�Cy \\ t 0.5114 ACRES \ \\ F \\ OLD COPPELL ESTATES; LOTS 158 816 R BLOCK 1(Formerly Old Coppell Estates; Lots 15 and 16 Block 1) \ \ ' LOT 15R BLOCK 1: (,I 9 15R Original Lot 15 0.2645 Acres �I 1 Additional Area 0.0930 Acres \ o� 20 BLDG LINE \ —_N1_ _j Proposed Lot 15R 0.3575 Acres 1 oak \ \\ LOT 16R BLOCK 1: 16 004 z„ Original Lot 16 0.2200 Acres w °36' 3 W 4. , 2 6 S 10 "cedar 7 Additional Area 0.2511 Acres Proposed Lot 16R 0.4711 Acres " pecan ZONING PARKLAND DEDICATION NOTES 1. TREES ARE SHOWN FOR ENGINEERING PURPOSES ONLY. SEE TREE SURVEY FOR DETAILED TREE DATA PRESENTATION AND MITIGATION PLAN. 2. EROSION PROTECTION ALONG THE CREEK BANKS MAY BE NEEDED DUE TO THE EROSIVE NATURE OF THE SOILS. 3. THE MINIMUM FINISH FLOOR ELEVATIONS FOR THESE LOTS ARE AS SHOWN. THE MINIMUM FINISH FLOOR ELEVATIONS FOR LOTS 15R AND 16R I Z�p"KlJjl ARE THE SAME AS THEIR ORIGINAL PLATTING. THESE MINIMUM FINISH FLOOR ELEVATIONS HAVE BEEN ESTABLISHED IN ACCORDANCE WITH THE CITY OF COPPELL'S FLOODPLAIN MANAGEMENT ORDINANCE. " PD CONDITIONS ®DjP,g.Y A. NO DEVELOPMENT WILL BE ALLOWED Yv1THIN THE 100 -YEAR FLOODPLAIN PRIOR TO AN APPROVED LETTER OF MAP AMENDMENT. A CONDITIONAL LETTER OF MAP AMENDMENT SHALL BE PROVIDED BY THE OWNER PRIOR TO THE POOL AND FENCING CONSTRUCTION OF LOT 2. B. LOT 1 FENCING: REAR FENCES SHALL BE 4' TALL DECORATIVE METAL, WEST SIDE YARD FENCES SHALL BE 4' TO 8' TALL DECORATIVE METAL AND 1 6g° g9 ''�- EAST SIDE YARD FENCES SHALL BE 4' TO 8' DECORATIVE METAL OR WOOD. FRONT FENCING AS SHOWN. 8 � � �o��' C. LOT 2 FENCING: REAR FENCES SHALL BE 4' TALL DECORATIVE METAL, SIDE YARD FENCES SHALL BE 4' TO 8' TALL DECORATIVE METAL OR WOOD. FRONT FENCING AS SHOWN. --..1 D. THE CITY OF COPPELL WILL HAVE NO RESPONSIBILITY FOR MAINTENANCE OF THE FLOODWAY /FLOODPLAIN AREAS AS SHOWN HEREON, HOWEVER THE IT 35 '� y51X -- — CITY DOES HAVE THE AUTHORITY TO REGULATE ACTIVITY IN THE FLOOD WAY /FLOODPLAIN AS PER THE CITY'S FLOODPLAIN ORDINANCE. THE h0" �� ��' yIX i MAINTENANCE OF THESE AREAS SHALL BE THE SOLE RESPONSIBILITY OF THE INDIVIDUAL LOT OWNERS ADJACENT TO SAID AREAS. THESE AREAS ARE s J TO REMAIN FREE OF IMPROVEMENTS THAT MAY OBSTRUCT THE FLOW OF S'ORMWATER AND PROTECTED FROM POTENTIAL EROSION BY THE OWNERS. NO FENCES WILL BE ALLOWED IN THE FLOODPLAIN ALONG WITH ANY OTHER STRUCTURES AS' PER THE-CITY'S FLOIPLAIN ORDINANCE_ E. RESIDENCE CHIMNEYS MAY EXTEND ABOVE THE MAXIMUM ROOFLtNE HEIGHT PF 35 FEET. oj<eQ a� /� \ BIG CEDAR E S TA 7E S 1 F. LOTS SHALL HAVE NO ALLEYS. G. LOT 1 SHALL PROVIDE TWO 3" CALIPER REPLACEMENT TREES. ado I H. LOT 2 SHALL PROVIDE SIX 3" CALIPER REPLACEMENT TREES. a� ter( I. A TREE REMOVAL PERMIT IS REQUIRED FOR THIS DEVELOPMENT. ���f �I G — J. A PARK DEDICATION FEE OF $1,285.00 PER DWELLING UNIT IS REQUIRED. 9 i 1 � 1 1 � 1 MAP 6: Site Plan PD 17682 Lots 1 & 2 Block 1, Bethel Road Estates Phase 11 1 =J7 E. 1st Street ANDES art 'Worth, Tex os 76' 8`7 870 -1220 8,7 870 -1292 �7o,: CIVIL/ ENVIRONMENTAL ENGINEERING Project No. J00014 File J00014 /Mop6SitePlanPD176P2.dvs vt f UST D. LANDES f Ali °mss _ 68081 a.: PROJECT STATUS: PRELIMINARY -FOR REVIEW ONLY FRONT FENCE ELEVATION NTS REVISIONS: ICK HOR. SCALE: JUNE 1 1) = 3`0' 2001 I� tj VERTICAL SCALE: a� NONE r� N ' 1 OF 1 11 s . ° ti •• 1 !! pecan Ce Lot 1 lock 1 Bethel Road Estates Phase II 0.529 AC. r ASSN 261' WAGE HEIGHT 8' BLDG LINE e ESIDE CE L t 2 Block -I ce B hel Road Mates Phase It \ 0.5114 AC. TRIP iW a: S01 000'47 "W 241.0 WENDY WEBSTER ZONING C I I NEAREST DRIVEWAY BETHEL ROAD ESTATES FLOOD STUDY COPPELL, TEXAS 16" © 14 oak EXISTING TREE TO REMAIN 6 " EXISTING TREE TO BE REMOVED pecan EXISTING 100 -YEAR FLOOOPLAIN \ EXISTING 100 -YEAR FLOODWAY PROPOSED FRONT FENCE \ \ OLD COPPELL ESTATES �S�_,BLDG \-Il \\ ZONING SF 9 LOT AREAS \� \\ r BETHEL ROAD ESTATES PHASE 11 (Formerly McMillan Estates; one lot at 1.7281 Acres) EXISTING \ \ LOT 1 BLOCK 1: RESIDENCE \ 0.5292 ACRES Lot 15R Block 1 \ I I Old Coppell Estates \ ''\ 14 LOT 2 BLOCK 1: 0.3575 AC. A�Cy \\ t 0.5114 ACRES \ \\ F \\ OLD COPPELL ESTATES; LOTS 158 816 R BLOCK 1(Formerly Old Coppell Estates; Lots 15 and 16 Block 1) \ \ ' LOT 15R BLOCK 1: (,I 9 15R Original Lot 15 0.2645 Acres �I 1 Additional Area 0.0930 Acres \ o� 20 BLDG LINE \ —_N1_ _j Proposed Lot 15R 0.3575 Acres 1 oak \ \\ LOT 16R BLOCK 1: 16 004 z„ Original Lot 16 0.2200 Acres w °36' 3 W 4. , 2 6 S 10 "cedar 7 Additional Area 0.2511 Acres Proposed Lot 16R 0.4711 Acres " pecan ZONING PARKLAND DEDICATION NOTES 1. TREES ARE SHOWN FOR ENGINEERING PURPOSES ONLY. SEE TREE SURVEY FOR DETAILED TREE DATA PRESENTATION AND MITIGATION PLAN. 2. EROSION PROTECTION ALONG THE CREEK BANKS MAY BE NEEDED DUE TO THE EROSIVE NATURE OF THE SOILS. 3. THE MINIMUM FINISH FLOOR ELEVATIONS FOR THESE LOTS ARE AS SHOWN. THE MINIMUM FINISH FLOOR ELEVATIONS FOR LOTS 15R AND 16R I Z�p"KlJjl ARE THE SAME AS THEIR ORIGINAL PLATTING. THESE MINIMUM FINISH FLOOR ELEVATIONS HAVE BEEN ESTABLISHED IN ACCORDANCE WITH THE CITY OF COPPELL'S FLOODPLAIN MANAGEMENT ORDINANCE. " PD CONDITIONS ®DjP,g.Y A. NO DEVELOPMENT WILL BE ALLOWED Yv1THIN THE 100 -YEAR FLOODPLAIN PRIOR TO AN APPROVED LETTER OF MAP AMENDMENT. A CONDITIONAL LETTER OF MAP AMENDMENT SHALL BE PROVIDED BY THE OWNER PRIOR TO THE POOL AND FENCING CONSTRUCTION OF LOT 2. B. LOT 1 FENCING: REAR FENCES SHALL BE 4' TALL DECORATIVE METAL, WEST SIDE YARD FENCES SHALL BE 4' TO 8' TALL DECORATIVE METAL AND 1 6g° g9 ''�- EAST SIDE YARD FENCES SHALL BE 4' TO 8' DECORATIVE METAL OR WOOD. FRONT FENCING AS SHOWN. 8 � � �o��' C. LOT 2 FENCING: REAR FENCES SHALL BE 4' TALL DECORATIVE METAL, SIDE YARD FENCES SHALL BE 4' TO 8' TALL DECORATIVE METAL OR WOOD. FRONT FENCING AS SHOWN. --..1 D. THE CITY OF COPPELL WILL HAVE NO RESPONSIBILITY FOR MAINTENANCE OF THE FLOODWAY /FLOODPLAIN AREAS AS SHOWN HEREON, HOWEVER THE IT 35 '� y51X -- — CITY DOES HAVE THE AUTHORITY TO REGULATE ACTIVITY IN THE FLOOD WAY /FLOODPLAIN AS PER THE CITY'S FLOODPLAIN ORDINANCE. THE h0" �� ��' yIX i MAINTENANCE OF THESE AREAS SHALL BE THE SOLE RESPONSIBILITY OF THE INDIVIDUAL LOT OWNERS ADJACENT TO SAID AREAS. THESE AREAS ARE s J TO REMAIN FREE OF IMPROVEMENTS THAT MAY OBSTRUCT THE FLOW OF S'ORMWATER AND PROTECTED FROM POTENTIAL EROSION BY THE OWNERS. NO FENCES WILL BE ALLOWED IN THE FLOODPLAIN ALONG WITH ANY OTHER STRUCTURES AS' PER THE-CITY'S FLOIPLAIN ORDINANCE_ E. RESIDENCE CHIMNEYS MAY EXTEND ABOVE THE MAXIMUM ROOFLtNE HEIGHT PF 35 FEET. oj<eQ a� /� \ BIG CEDAR E S TA 7E S 1 F. LOTS SHALL HAVE NO ALLEYS. G. LOT 1 SHALL PROVIDE TWO 3" CALIPER REPLACEMENT TREES. ado I H. LOT 2 SHALL PROVIDE SIX 3" CALIPER REPLACEMENT TREES. a� ter( I. A TREE REMOVAL PERMIT IS REQUIRED FOR THIS DEVELOPMENT. ���f �I G — J. A PARK DEDICATION FEE OF $1,285.00 PER DWELLING UNIT IS REQUIRED. 9 i 1 � 1 1 � 1 MAP 6: Site Plan PD 17682 Lots 1 & 2 Block 1, Bethel Road Estates Phase 11 1 =J7 E. 1st Street ANDES art 'Worth, Tex os 76' 8`7 870 -1220 8,7 870 -1292 �7o,: CIVIL/ ENVIRONMENTAL ENGINEERING Project No. J00014 File J00014 /Mop6SitePlanPD176P2.dvs vt f UST D. LANDES f Ali °mss _ 68081 a.: PROJECT STATUS: PRELIMINARY -FOR REVIEW ONLY FRONT FENCE ELEVATION NTS REVISIONS: ICK HOR. SCALE: JUNE 1 1) = 3`0' 2001 VERTICAL SCALE: SHEET NONE 1 OF 1 NOTES: 1. The MINIMUM FINISH FLOOR ELEVATIONS shown for these lots are subject to change. FINAL MINIMUM FINISH FLOOR elevations will be determined upon completion of a Letter of Map Revision through FEMA and in accordinace with the City of Coppell's Floodplain Management Ordinance. 2. Rear yards will be filled to maintain MINIMUM FINISH FLOOR ELEVATIONS (497.6) in order to secure future swimming pool construction. The existing floodplain elevation at these lots is 494.0. The proposed MINIMUM FINISH FLOOR elevation of 497.6 is 3.6 feet above the existing floodplain. A revised flood study of this area B I G C E D A D D I T 1 0 N is currently under way. Upon completion of this study, an ultimate floodplain VOL. I PG. 3455 \ ® ® 2 ' elevation will be determined based upon the new fill and grading scheme. The N 4 �/ 3 MINIMUM FINISH FLOOR elevations for these homes will be established at one foot above the ultimate floodplain water surface. Preliminary HEC -2 runs of this study \ Y O I indicate that the ultimate floodplain water surface at these lots will be approximately 496.6. The preliminary MINIMUM FINISH FLOOR elevation of 497.6 is one foot higher. The only other known source of ultimate floodplain elevations for \ 5 ( % / this area, is the 1990 Albert Halff study. The Halff study does not reflect the BEGIN EXIST. 10" SS \ ® floodplain fill and grading of the creek that was made in 1993 with the REMOVAL ® / construction of the Big Cedar Creek addition, and therefore is not the most reliable source in this area of the study. Additionally, due to other site constraints, the ACTUAL FINISH FLOOR elevation of Lot 1 will be 500.5, which is 6.5 feet above the existing floodplain elevation and 3.9 feet above the preliminary ultimate -- floodlain elevation. Again, due to other site constraints, the ACTUAL FINISH FLOOR ® / 5 %� / �� ¢81 °� elevation of Lot 2 is 498.2, which is 4.2 feet above the existing floodplain and 1.6 6 � / ��� — — feet above the preliminary ultimate floodplain elevation. s "N 88.55'03" E - 2 \ 3. No development will be allowed within the 100 -Year Floodplain before a flood SCALE: 1' = 30' V A i { L V study is submitted and approved. A H 14" 4. Due to the typical erosion of creeks, creek embankment stabilization may be V necessary. A 0 M. `1� _ 5. Trees are shown for engineering purposes only. See Tree Survey for detailed' _' E EL 1 ` tree data presentation and mitigation plan. A �� J _ ` 6. No home footprints are avoiable at this time. These lots will be sold as ELM NO DISTURBANCE "build to suit" lots. 1 ® `` // ELM ® AX 7. The existing 10 "sewer line beneath lot 2 will be abandoned and removed as ELM 7 shown. ® ELM 8" ' L W 0' � ® 8. Rear fences shall be 4' tall wrought iron, while side yard fences shall be 6' to ® M 6�/ OAK 32' 8' tall wrought iron or wood. OAK 22" % �1 9. Final grades for the driveways and front fences will be coordinated with the OAK 13" City's Engineering department in order to minimize future conflicts with the 0/ EL 1 FLOOD WAY 12 (� reconstruction of Bethel Road. � o 8 ° ,ge �/� 10" PROP 10" SS ELOVATION\ ( 01 i 10. No vehicular backing onto Bethel Road will be allowed. IST. a 9 sSMH If is 495 1 \ LEGEND / S L P SSg H I \\ Q !o� EXIST CONTOUR �� Soo / p k \ ti Co 4976 � SS / ase S EN FLOOD STUDY COPPELL, TEXAS - 17] CL CREEK APP OXIMATE LOCATION OF o ` � \ '°o EXIST TREE PECAN 12" PR FLOODPLAIN LIMITS 4 6 \ \ v ass 0 3' j / ) ` EXIST FLOODPLAIN `t 49 ® C R 1 NO DISTURBANCE 0 PROP FLOODPLAIN � N PECAN 12" 497. PROP CONTOUR 0 496 RETAINING i Ir ( - �' WALL R.L. McDOWELL & RG'BY McDOWELL PROP GRADE 8497.7 _ X97 _ y 105' PREP . RIB TAIF� 'WALL .� 13 MIN. SID YARD AINING 00 LOT 2 \ R PROP FRONT FENCE o 0 0 0 0 0 0 o a m 00 2.348 AC. Ilk (D MIN. F.F. 497.6 482 a00 A ` PROP REAR & SIDE FENCES a a• a e- 10,000 SF PAD CEDAR i _ - ACTUAL FINISH 1 PROP VEHICULAR FLOW FLOOR 498.2 y AK 6 495.0 C�\ D{r��`_ CAST CEMENT COLUMN TOPS 13' E 18"-24" TYPICAL ON 12' CENTERS S WELDED METAL, PAINTED FENCE y COMBINATION BRICK TION COLUMNS I i' `P ww 1R • Tiei a »i N_ a As MAP 5: Site Plan PD 181 Lots 1 & 2 Block 1, Bethel Road Estates 'I� I DALLAS j man 11�01 FUTURE 50' ROW W CONCRETE FOOTING �, ,f� is • I� PROJECT STATUS: J9,ES PROP D.O. BRICK E. 1st Street Texas 76102 *r AND 817 70-1 870 -1220 COLUMN r WELDED METAL VOL Y r : .9.5 4° , all .a � a � ',' .. FENCE EQUAL TO WEND 0.857 � 68081 l �'`F CIVIL ENVIRONMENTAL s 0 160 . • S PAD iWEBSTER FENCE FLOOD STUDY COPPELL, TEXAS - 17] CL CREEK APP OXIMATE LOCATION OF o ` � \ '°o EXIST TREE PECAN 12" PR FLOODPLAIN LIMITS 4 6 \ \ v ass 0 3' j / ) ` EXIST FLOODPLAIN `t 49 ® C R 1 NO DISTURBANCE 0 PROP FLOODPLAIN � N PECAN 12" 497. PROP CONTOUR 0 496 RETAINING i Ir ( - �' WALL R.L. McDOWELL & RG'BY McDOWELL PROP GRADE 8497.7 _ X97 _ y 105' PREP . RIB TAIF� 'WALL .� 13 MIN. SID YARD AINING 00 LOT 2 \ R PROP FRONT FENCE o 0 0 0 0 0 0 o a m 00 2.348 AC. Ilk (D MIN. F.F. 497.6 482 a00 A ` PROP REAR & SIDE FENCES a a• a e- 10,000 SF PAD CEDAR i _ - ACTUAL FINISH 1 PROP VEHICULAR FLOW FLOOR 498.2 y AK 6 495.0 C�\ D{r��`_ CAST CEMENT COLUMN TOPS 13' E 18"-24" TYPICAL ON 12' CENTERS S WELDED METAL, PAINTED FENCE y COMBINATION BRICK TION COLUMNS I i' `P ww 1R • Tiei a »i N_ a As MAP 5: Site Plan PD 181 Lots 1 & 2 Block 1, Bethel Road Estates 'I� I DALLAS j man 11�01 FUTURE 50' ROW W CONCRETE FOOTING PROJECT STATUS: J9,ES PROP D.O. BRICK E. 1st Street Texas 76102 *r AND 817 70-1 870 -1220 COLUMN r WELDED METAL 011 all 870 -1292 Fax JUSTIN D. LANDES FENCE EQUAL TO WEND � 68081 l �'`F CIVIL ENVIRONMENTAL iWEBSTER FENCE Proiect No. J00014 I File J00014 /Mao5SitePldnPD181.dwa END EXIST. 10 SS REMOVAL AND PLUG PROP ROW EX .. FUTURE ! ROW EXIST u. FLOOD STUDY COPPELL, TEXAS - 17] CL CREEK APP OXIMATE LOCATION OF o ` � \ '°o EXIST TREE PECAN 12" PR FLOODPLAIN LIMITS 4 6 \ \ v ass 0 3' j / ) ` EXIST FLOODPLAIN `t 49 ® C R 1 NO DISTURBANCE 0 PROP FLOODPLAIN � N PECAN 12" 497. PROP CONTOUR 0 496 RETAINING i Ir ( - �' WALL R.L. McDOWELL & RG'BY McDOWELL PROP GRADE 8497.7 _ X97 _ y 105' PREP . RIB TAIF� 'WALL .� 13 MIN. SID YARD AINING 00 LOT 2 \ R PROP FRONT FENCE o 0 0 0 0 0 0 o a m 00 2.348 AC. Ilk (D MIN. F.F. 497.6 482 a00 A ` PROP REAR & SIDE FENCES a a• a e- 10,000 SF PAD CEDAR i _ - ACTUAL FINISH 1 PROP VEHICULAR FLOW FLOOR 498.2 y AK 6 495.0 C�\ D{r��`_ CAST CEMENT COLUMN TOPS 13' E 18"-24" TYPICAL ON 12' CENTERS S WELDED METAL, PAINTED FENCE y COMBINATION BRICK TION COLUMNS I i' `P ww 1R • Tiei a »i N_ a As MAP 5: Site Plan PD 181 Lots 1 & 2 Block 1, Bethel Road Estates 'I� I DALLAS j man 11�01 FUTURE 50' ROW W CONCRETE FOOTING t_ 6r ' FRONT FENCE ELEVATION NTS REVISIONS: HOR. SCALE: JUNE 1'= 30' 2001 vERT. scALE: SHEET NONE 10171 PROJECT STATUS: J9,ES 107 Fort E. 1st Street Texas 76102 *r AND 817 70-1 870 -1220 t PRELIMINARY -FOR REVIEW ONLY 011 817 870 -1292 Fax JUSTIN D. LANDES � 68081 l �'`F CIVIL ENVIRONMENTAL ENGINEERING Proiect No. J00014 I File J00014 /Mao5SitePldnPD181.dwa t_ 6r ' FRONT FENCE ELEVATION NTS REVISIONS: HOR. SCALE: JUNE 1'= 30' 2001 vERT. scALE: SHEET NONE 10171