1. by David M. Beekman and Vito A. Cimino
Experience of Flood Analysis in the Ohio River Basin Using ArcView GIS for HEC-RAS Flow Computation
by David M. Beekman and Vito A. Cimino
Co-authored by Dr. Tiao Chang Department of Civil Engineering, Ohio University
Terri Dawson, Coy Miller, Jerry Web US Army Corps of Engineers, Water Resources Engineering

2. Objectives Generate channel cross sections using HEC-2 data
Convert existing HEC-2 data to HEC-RAS
Geo-Reference data using ArcView GIS
Present Inundation Mapping

3. Project Location
Alum Creek

4. What’s Required? Existing HEC-2 data for desired reach
USGS 1:24,000 DLG data
Software
HEC-RAS
ArcView GIS

5. Procedure Outline Spatial Data Management Cross Section Generation
Pre-processing
Hydraulic Flow Computations
Final DEM Production
Post-processing
Final Inundation Map Production

6. Spatial Data Management
Download USGS 1:24,000 DLGs
Hypsography
Hydrography
Roads
Convert to shapefiles in ArcView
Delineate stream centerline and banks

7. Cross Section Generation
Analysis of HEC-2 Data
Cross section lengths
Distance between
adjacent cross sections
Cross section elevations

8. Cross Section Generation (cont.)
Application of ArcView
Constructed manually
Based on topography and cross section survey data
Cross section stationing and distance calculations
(use of AVRAS 2.2 – ArcView extension)

9. Geo-Referenced Cross Sections

10. Pre-processing Preparation of temporary terrain TIN
USGS hypsography DLGs
Implement AV-RAS options in ArcView
(use of AVRAS 2.2 – ArcView extension)

11. Pre-processing (cont.)
Select AV-RAS theme setup
TIN
Cross sections
Centerline
Banks
Flow path

12. Pre-processing (cont.)
Complete remaining AV-RAS options
Generate *.geo file
Import file for HEC-RAS
Consists of ArcView geometric data

13. HEC-2 X-sections
Preprocessed X-sections

14. Hydraulic Flow Computation
Adjust GIS geometry file according to HEC-2 data in HEC-RAS
Ground elevations
Cross section lengths

15. Hydraulic Flow Computation
Adding parameters
Manning’s‘n’ values
Contraction/Expansion coefficients
Bridges/Piers
Steady flow data
Run water surface profile computations
Model verification
Generate *.gis file (HEC-RAS export file)

16. Final DEM Production
Run Avenue script to export cross sections into ArcView
Cross section and point elevation shapefiles generated
Based on HEC-RAS geometry data
Point elevation data (original HEC-2 data)
Topographical elevation data (USGS data)
Final DEM produced

17. Final DEM

18. Post-processing Implement RAS-AV options in ArcView
(use of AVRAS 2.2 – ArcView extension)

19. Post-processing (cont.)
Select RAS-AV theme setup
HEC-RAS *.gis export file
Creation of output directory
Terrain TIN
Rasterization cell

20. Post-processing (cont.)
Complete remaining RAS-AV options
Select desired water surface elevations
Floodplain delineation

21. Alum Creek Floodplain
4,200 cfs
6,500 cfs
8,100 cfs
13,600 cfs

22. Final Inundation Mapping
4,200 cfs

23. Final Inundation Mapping
6,500 cfs

24. Final Inundation Mapping
8,100 cfs

25. Final Inundation Mapping
13,600 cfs

26. Conclusions Converted HEC-2 data to HEC-RAS
Created cross sections to geographically reference HEC-2 data with ArcView GIS
Performed hydraulic flow analysis with HEC-RAS
Presented Inundation Mapping for floodplain delineation

27. U.S. Army Corps of Engineers, Huntington District
Acknowledgements
Ohio University
U.S. Army Corps of Engineers, Huntington District

28. Questions?