Regional Hydraulic Model for the City of Austin CE 394 K2 - Surface Water Hydrology Esteban Azagra
Objectives Create a “regional hydraulic model” for the city of Austin. Specific goal: flow analysis. Dentritic network Single Creek
Tools CRWR-PrePro: ArcView preprocessor that extracts information from digital spatial data and creates an input file for non-GIS applications. HEC-HMS: Hydrologic Modeling System for precipitation-runoff simulation. HEC-RAS: one-dimensional Hydraulic Model for channel analysis and floodplain determination.
Methodology Watershed delineation and HMS schematic generation with PrePro. Generate flows with HEC-HMS. Compare flows and run HEC-RAS.
Sample Area Branched Relatively flat Cross-sections available Bull Creek Little Bull Creek Branched Relatively flat Cross-sections available
Data required for the Study Bull Creek Boundaries (City of Austin) River Reach File 3 Coverage (EPA) 10 m DEM (City of Austin) Land Use/Land Cover files (USGS) Precipitation data (CRWR) Cross-Sections in GIS format (CRWR) RAS files (City of Austin) STATSGO (USDA-NRCS)
Working with CRWR-PrePro DEM Fill Streams Basic Stream Network “Burning in” Flow dir. Flow acc. Control Points, Outlets and Links Delineate watersheds
Working with CRWR-PrePro Stream Parameters X = 0.15, V = 1 m/s Vectorization CN LULC Statsgo Computation of the hydrologic parameters HMS “Clipping out” Schematic and basin file
Running HEC-HMS (Basin Model)
Running HEC-HMS (Precipitation Model) Flooding analysis based on: 2, 10, 25, 100 yr hypothetical storms 3 hr storm duration
Running HEC-HMS (Control Specifications)
Running HEC-HMS (Results) Hydrograph Plot Hydrograph Time Table Hydrograph Summary
Flow analysis
Conclusions Differences are too big! Check City of Austin flow values. Model calibration? (X, Vs) Very suitable approach for flow determinations. Analysis of big areas. HMS flow values can be exported to RAS.
Future work GIS representation of flooded areas. Work with DOQ’s. AVRAS. Other approaches (TIN not available).
Questions