Application of GIS Tools for Hydraulic Modeling
Overview Introduction to floodplain mapping Why use GIS? Problems Tools and Data Process Results Future Questions
Floodplain Mapping Process Gather Data Hydrologic Analysis Hydraulic Analysis Map Floodplain Using Outputs and Base Maps
Why Use GIS? Delineation of watershed boundaries and parameter estimation is simplified Input of topographic data far less labor intensive Import and Export of data between ArcView and HEC-HMS and HEC-RAS is convenient Amount of labor associated with hand delineation makes adjustments cost-prohibitive
Problems of GIS Gathering data sufficiently accurate for terrain modeling Significant processing time due to size of datasets Matching datasets with different projections
GIS Tools and Data Required Spatial Analyst 3-D Analyst HEC-GeoRAS HEC-RAS 3.0 Triangulated Irregular Network of Clear Creek
3-D Analyst Extension
3-D Analyst Extension
Hydrologic Analysis Calculate Parameters Enter into HEC-HMS Get Flow Data for Later Use in HEC-RAS
Process Load GeoRAS Extension for ArcView
Terrain Model Generate TIN
Terrain Model Create Contours
Hydraulic Process Identify Channel Centerline
Hydraulic Process Draw Right and Left Banks
Hydraulic Process Draw Flowpaths for Channel and Overbanks
Hydraulic Process Insert Desired Cross Section Lines
Hydraulic Process Curves in Stream Calculated using Flowpaths
Prepare GIS Data for Export HEC-GeoRas Theme Setup
Creating RAS/GIS Import File Stream/Reach Names Stationing Bank Stations Reach Names Manning’s ‘n’ Values Cross Section Elevations
Importing GeoRAS Data Create New HEC-RAS Project Import GIS Geometry Data
Using HEC-RAS Add data for hydraulic structures Add roughness values Input flow data View results Export back to GIS
Create Flow Depth Grid
Analyze Results Detention Pond Main Channel
Comparison of Flows 5000 CFS 2500 CFS
Questions ???