1. Application of GIS Tools for Hydraulic Modeling

2. Overview Introduction to floodplain mapping Why use GIS? Problems
Tools and Data
Process
Results
Future
Questions

3. Floodplain Mapping Process
Gather Data
Hydrologic Analysis
Hydraulic Analysis
Map Floodplain Using Outputs and Base Maps

4. 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

5. Problems of GIS
Gathering data sufficiently accurate for terrain modeling
Significant processing time due to size of datasets
Matching datasets with different projections

6. GIS Tools and Data Required
Spatial Analyst
3-D Analyst
HEC-GeoRAS
HEC-RAS 3.0
Triangulated Irregular Network of Clear Creek

7. 3-D Analyst Extension

8. 3-D Analyst Extension

9. Hydrologic Analysis Calculate Parameters Enter into HEC-HMS
Get Flow Data for Later Use in HEC-RAS

10. Process
Load GeoRAS Extension for ArcView

11. Terrain Model
Generate TIN

12. Terrain Model
Create Contours

13. Hydraulic Process
Identify Channel Centerline

14. Hydraulic Process
Draw Right and Left Banks

15. Hydraulic Process
Draw Flowpaths for Channel and Overbanks

16. Hydraulic Process
Insert Desired Cross Section Lines

17. Hydraulic Process
Curves in Stream Calculated using Flowpaths

18. Prepare GIS Data for Export
HEC-GeoRas Theme Setup

19. Creating RAS/GIS Import File
Stream/Reach Names
Stationing
Bank Stations
Reach Names
Manning’s ‘n’ Values
Cross Section Elevations

20. Importing GeoRAS Data Create New HEC-RAS Project
Import GIS Geometry Data

21. Using HEC-RAS Add data for hydraulic structures Add roughness values
Input flow data
View results
Export back to GIS

22. Create Flow Depth Grid

23. Analyze Results
Detention Pond
Main Channel

24. Comparison of Flows
5000 CFS
2500 CFS

25. Questions ???