DRAFT REPORT TXDOT SH 183 MASTER DRAINAGE STUDY HYDRAULIC ANALYSIS OF ELM FORK OF TRINITY RIVER CROSSING AT SH 183 WITHIN THE ELM FORK WATERSHED

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1 DRAFT REPORT TXDOT SH 183 MASTER DRAINAGE STUDY HYDRAULIC ANALYSIS OF ELM FORK OF TRINITY RIVER CROSSING AT SH 183 WITHIN THE ELM FORK WATERSHED FOR TEXAS DEPARTMENT OF TRANSPORTATION DALLAS DISTRICT CONTRACT NO P5027 BY HALFF ASSOCIATES, INC NORTHWEST PLAZA DRIVE DALLAS, TEXAS (214) July 2007 AVO 19474

2 I. General Existing Structure Description TxDOT SH 183 Master Drainage Study Elm Fork of the Trinity River The modeled portion of the SH 183 bridge spans approximately 1,530 feet over the Elm Fork of the Trinity River. The modeled bridge is located between two levees. The west levee is in the City of Irving and is maintained by Irving Flood Control District (IFCD). The east levee is maintained by the City of Dallas. The Elm Fork forms the city boundary between Dallas and Irving. The bridge is located approximately 1,800 feet from the Regal Row exit on SH 183. The total width of the existing bridge is 132 feet. Figure 1 shows photographs of the existing bridge. II. Hydrology and Existing CDC Hydraulic Model The existing conditions hydraulic model was created by the U.S. Army Corps of Engineers for Corridor Development Certificate (CDC) evaluations. Per the description in the HEC-RAS model, the last model update was in November The CDC model covers the Upper Trinity River including the Main Stem, West, Clear, and Elm Forks. Elm Fork cross-sections in the vicinity of SH 183 were drawn to the top of the levees. The CDC model was updated by the Corps using HEC-RAS Version 4.0 Beta. The same version was used for the current hydraulic analysis. Downstream Face of Bridge Upstream Face of Bridge at IFCD Levee Figure 1. Photographs of the SH 183 over the Elm Fork of the Trinity River The flows used in this hydraulic analysis are from the CDC model. No new hydrologic analysis was performed to compute flows. The flow file in the CDC model indicates that the flows are based on fully developed conditions in the watershed. The existing CDC model contains two separate RAS geometry files. One geometry file contains the geometry for the 1-yr to 100-yr profiles and the other file contains the geometry for the 500-yr and SPF profiles from the CDC model. The CDC model has separate geometries due to the hydraulic behavior of the Trinity River. Table 1 shows the discharges that were applied at the bridge location. DRAFT 1

3 TxDOT SH 183 Master Drainage Study Elm Fork of the Trinity River Table 1. Existing CDC Peak Discharges Peak Discharges (cfs) 10-YR 25-YR 50-YR 100-YR 500-YR SPF Ultimate Conditions Elm Fork of the Trinity River at SH ,500 27,400 34,800 43,100 51, ,200 III. Revised Existing Hydraulic Analysis The hydraulic model from the CDC in the immediate vicinity of the SH 183 bridge over the Elm Fork was revised to incorporate data from 1978 Texas Department of Transportation (TxDOT) as-built plans which were verified by field reconnaissance. The existing model showed 23 sets of piers between the Dallas and IFCD levees which were 3 feet to 6 feet in diameter. From field reconnaissance, the number of piers was observed to be 26 and the size of piers was measured to be 2.5 feet with the exception of 4 sets of piers near the channel. The piers near the channel were measured to be 4 feet in diameter at the largest pier. The Manning s roughness values were also modified in the revised existing model based on field observations. Areas between the Dallas levee and the channel were assigned a Manning s n-value of 0.07 in the existing model. This roughness value was changed to 0.03 in the revised existing model because the vegetation in this area is mowed grass. The existing CDC model had a deck width of 130 feet whereas the aerial photo and as-built plans show the deck to be 132 feet wide. Table 2 provides a summary of water surface elevation comparisons between existing CDC and revised existing models for the 100-yr and SPF profiles. Table 2. Revised Existing Hydraulic Results 100-yr Water Surface Elevation Comparison River Station CDC Existing Elevation (ft) Revised Existing Elevation (ft) SPF Water Surface Elevation Comparison River Station CDC Existing Elevation (ft) Revised Existing Elevation (ft) Bridge Bridge DRAFT 2

4 IV. Proposed Bridge Hydraulic Analysis TxDOT SH 183 Master Drainage Study Elm Fork of the Trinity River The proposed TxDOT highway improvements will add new frontage roads and replace the existing SH 183 bridge with a wider and higher bridge. The proposed bridge will be approximately 410 feet wide based on May 2006 TxDOT preliminary schematic plans. The proposed structure span will remain the same as existing conditions. However, the height of bridge above the channel will increase approximately 7 feet. The existing foot and 4 foot diameter piers will be replaced by foot width rectangular piers. Pier locations input into the model were taken from preliminary schematic plans where proposed bent locations are shown. New deck information was entered into the model based on top of road and deck height for the proposed eastbound frontage road. The eastbound frontage road deck information was used because it has the lowest low-chord elevation. Existing cross-sections upstream and downstream were deleted from the model and new ones were added to represent the proposed bridge in the hydraulic model. The new crosssections were cut using Corps 2-foot topographic data that was used in the existing CDC model. Flow lines of the new cross-sections were interpolated between existing crosssection flow lines. Geometry changes were made to both the 1-yr to 100-yr geometry file and 500-yr to SPF geometry file. The hydraulics of the proposed SH 183 bridge were analyzed using the same methods and procedures as the existing structure hydraulics. Table 3 provides a summary of water surface elevation comparisons between revised existing and proposed models for the 100- yr and SPF profiles. Per the results, the 100-yr is contained within the levees; however, the levees do not contain 500-yr and SPF profiles. Table 3. Proposed Hydraulic Results 100-yr Water Surface Elevation Comparison River Station Revised Existing Elevation (ft) Proposed Elevation (ft) SPF Water Surface Elevation Comparison River Station Revised Existing Elevation (ft) Proposed Elevation (ft) Bridge Bridge DRAFT 3

5 V. Conclusions TxDOT SH 183 Master Drainage Study Elm Fork of the Trinity River The water surface elevations from the existing, revised existing, and proposed models were compared for 100-yr, 500-yr and SPF profiles. Due to a decrease in roughness values and size of piers, the water surface elevations were calculated to be slightly lower for the revised existing model compared to the CDC model. Water surface elevation comparisons between proposed and revised existing model results show that proposed elevations are equal to or slightly lower than the revised existing conditions. This is due to the decrease in the number of piers for proposed conditions. The Appendix includes detailed HEC-RAS output as well as a proposed bridge schematic and the existing SH 183 bridge TxDOT as-built plans. DRAFT 4

6 APPENDIX

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25 Elm Fork at SH yr WSEL Comparison Existing Revised Existing Proposed Reach River Sta Profile Q Total W.S. Elev Reach River Sta Profile Q Total W.S. Elev Δ WSEL Reach River Sta Profile Q Total W.S. Elev Δ WSEL (cfs) (ft) (cfs) (ft) (ft) (cfs) (ft) (ft) ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR I:\19000s\19474\HH\xls\WSEL Comparison.xls Page 1 of 2 7/20/2007

26 Elm Fork at SH yr WSEL Comparison Existing Revised Existing Proposed Reach River Sta Profile Q Total W.S. Elev Reach River Sta Profile Q Total W.S. Elev Δ WSEL Reach River Sta Profile Q Total W.S. Elev Δ WSEL (cfs) (ft) (cfs) (ft) (ft) (cfs) (ft) (ft) ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR Note: The revised existing model includes XS data from the existing model plus added XS 14808, XS and XS The width of SH183 bridge was changed from 132 to 131 because RAS won't run if reach length is equal to dist to US XS+deck width I:\19000s\19474\HH\xls\WSEL Comparison.xls Page 2 of 2 7/20/2007

27 Elm Fork at SH yr WSEL Comparison Existing Revised Existing Proposed Reach River Sta Profile Q Total W.S. Elev Reach River Sta Profile Q Total W.S. Elev Δ WSEL Reach River Sta Profile Q Total W.S. Elev Δ WSEL (cfs) (ft) (cfs) (ft) (ft) (cfs) (ft) (ft) ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR I:\19000s\19474\HH\xls\WSEL Comparison.xls Page 1 of 2 7/20/2007

28 Elm Fork at SH yr WSEL Comparison Existing Revised Existing Proposed Reach River Sta Profile Q Total W.S. Elev Reach River Sta Profile Q Total W.S. Elev Δ WSEL Reach River Sta Profile Q Total W.S. Elev Δ WSEL (cfs) (ft) (cfs) (ft) (ft) (cfs) (ft) (ft) ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef Bridge ef Bridge ef Bridge ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR ef YEAR Note: The revised existing model includes XS data from the existing model plus added XS 14808, XS and XS The width of SH183 bridge was changed from 132 to 131 because RAS won't run if reach length is equal to dist to US XS+deck width I:\19000s\19474\HH\xls\WSEL Comparison.xls Page 2 of 2 7/20/2007

29 Elm Fork at SH183 SPF WSEL Comparison Existing Revised Existing Proposed Reach River Sta Profile Q Total W.S. Elev Reach River Sta Profile Q Total W.S. Elev Δ WSEL Reach River Sta Profile Q Total W.S. Elev Δ WSEL (cfs) (ft) (cfs) (ft) (ft) (cfs) (ft) (ft) ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef Bridge ef Bridge ef Bridge ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef Bridge ef Bridge ef Bridge ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef Bridge ef Bridge ef Bridge ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF I:\19000s\19474\HH\xls\WSEL Comparison.xls Page 1 of 2 7/20/2007

30 Elm Fork at SH183 SPF WSEL Comparison Existing Revised Existing Proposed Reach River Sta Profile Q Total W.S. Elev Reach River Sta Profile Q Total W.S. Elev Δ WSEL Reach River Sta Profile Q Total W.S. Elev Δ WSEL (cfs) (ft) (cfs) (ft) (ft) (cfs) (ft) (ft) ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef Bridge ef Bridge ef Bridge ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef Bridge ef Bridge ef Bridge ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef Bridge ef Bridge ef Bridge ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF ef SPF Note: The revised existing model includes XS data from the existing model plus added XS 14808, XS and XS The width of SH183 bridge was changed from 132 to 131 because RAS won't run if reach length is equal to dist to US XS+deck width I:\19000s\19474\HH\xls\WSEL Comparison.xls Page 2 of 2 7/20/2007

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