WATERWAYS AND

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WATERWAYS AND BRIDGES IN TEXAS
CE 394K 11-22-05 Dr. Maidment
Final Presentation by Brandon Klenzendorf
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Background

• TxDOT to use crash-tested bridge rails
• May impact FEMA 100-year floodplains
• Cause for map revisions time and money!
• Need to determine how bridge rails affect water
  surface profiles

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TxDOT Design Frequencies
TxDOT Hydraulic Design Manual
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Project Purpose

• In order to solve this problem, we need to
  predict
• Hydraulic impact of crash-tested bridge rails
• 100-year peak flood discharges
• Determine peak discharge for 100-year return
  period flood
• Use GIS and NFF programs to gain info on flood
  discharges

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GIS Data Collection

• State of Texas HUCs from TNRIS
• http//www.tnris.state.tx.us/
• Major highway network from TNRIS
• Major stream network from TNRIS
• DEMs for selected bridges from USGS
• http//seamless.usgs.gov/

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ArcHydro Tools

• DEM processing
• Problems with gaps in stream layer
• Drainage line creation
• Batch point watershed delineation
• Longest upstream length
• Upstream and downstream elevations

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Bridge 1
Problems!
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USGS NFF Program

• National Flood Frequency Program
• Estimates the magnitude and frequency of flood
  peak discharges and hydrographs
• 2, 5, 10, 25, 50, 100, and 500-year frequency
  floods
• Uses Visual Basic and regression equations
  specific for each state
• FREE!!!
• http//water.usgs.gov/software/nff.html

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NFF Program Parameters

• Drainage Area (A) area (mi2) contributing to
  flow at the bridge
• Shape Factor (SH) ratio of stream length
  squared (mi2) to drainage area (mi2)
• Represents stream length to average width
• Stream Slope (SL) change in elevation (ft)
  divided by steam length (mi)

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Hydrologic Regions

• Determined based on physiography and climatic
  conditions
• Each hydrologic region has range of applicable
  parameters
• Hydrologic Region 1 - Q100371A0.847SH-0.307

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Determined NFF Parameters
Hydrologic Region Area (mi2) Upstream Length (mi) Slope (ft/mi) Shape Factor Latitude (DD) Longitude (DD)
R-1 1120.9 29.12 9.85 0.756 36.202 -101.306
R-2 548.4 17.16 37.62 0.537 31.878 -103.947
R-3 3408.1 45.53 13.24 0.608 34.090 -99.730
R-4 2098.0 40.19 7.77 0.770 32.399 -100.894
R-5 1447.0 43.04 11.66 1.280 29.514 -97.494
R-6 489.2 27.966 -98.973
R-7 1917.4 33.072 -97.532
R-8 2590.9 31.435 -97.759
R-9 571.0 28.703 -97.047
R-10 991.2 32.777 -95.798
R-11 923.2 30.396 -94.255
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NFF Interface
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Flood Region Map
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NFF Results

• 100-year hydrograph for five bridges
• Bridge 5 has largest peak, but third largest area
• Bridge 3 has second lowest peak, but largest area

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Completed Work

• Geodatabase of Texas rivers, highways, and HUCs
• ArcHydro tools for all bridges
• Batch point watershed delineation for all bridges
• Partial completion of longest stream length
• Partial completion of NFF analysis

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Future Work

• Longest stream lengths for remaining Hydrologic
  Regions
• NFF analysis for all bridges
• Comparison of results
• Analyze errors in DEMs, HUCs, and bridge
  locations
• Write final report

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Questions
?