WATERWAYS AND BRIDGES IN TEXAS “Final” Presentation by: Brandon Klenzendorf CE 394K Dr. Maidment
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
TxDOT Design Frequencies TxDOT Hydraulic Design Manual
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
GIS Data Collection ► State of Texas HUCs from TNRIS ► Major highway network from TNRIS ► Major stream network from TNRIS ► DEMs for selected bridges from USGS
ArcHydro Tools ► DEM processing Problems with gaps in stream layer ► Drainage line creation ► Batch point watershed delineation ► Longest upstream length ► Upstream and downstream elevations
Bridge 1 Problems!
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!!! ►
NFF Program Parameters ► Drainage Area (A) – area (mi 2 ) contributing to flow at the bridge ► Shape Factor (SH) – ratio of stream length squared (mi 2 ) to drainage area (mi 2 ) Represents stream length to average width ► Stream Slope (SL) – change in elevation (ft) divided by steam length (mi)
Hydrologic Regions ► Determined based on physiography and climatic conditions ► Each hydrologic region has range of applicable parameters ► Hydrologic Region 1 - Q 100 =371A SH
Determined NFF Parameters Hydrologic Region Area (mi 2 ) Upstream Length (mi) Slope(ft/mi) Shape Factor Latitude(DD)Longitude(DD) R R R R R R R R R R R
NFF Interface
Flood Region Map
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
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
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
Questions ?