Floodplain modeling for Paddy's Run at the DOE Fernald Site

ABSTRACT

The restoration work for an intermittent stream, Paddy's Run, in the boundaries of the U.S. Department of Energy (DOE) Fernald Site, Ohio, managed by Fluor Fernald, involved floodplain expansion and the installation of grade control structures. Floodplain expansion was accomplished by removing earth berms at key locations where the stream was previously channeled. Cross-vane structures were constructed at selected locations both upstream and downstream of the floodplain expansion inlets.

MSE Technology Applications, Inc. (MSE) performed surface water flow modeling using both the pre- and post-restoration topography to examine how the floodplain would be affected by the planned restoration activities. The modeling was completed for 2-, 5-, 10-, 25-, 50-, and 100-year flood events. RiverCAD software, developed and distributed by BOSS International (BOSS), was used for floodplain modeling. This software is an improved and user-friendly Windows™ version of public domain software HEC-RAS originally developed by the U.S. Army Corps of Engineers (USCOE). RiverCAD computes water surface profiles for modeling bridges, culverts, spillways, levees, bridge scour, and other structures.

The Paddy's Run streamflow values, which are necessary for modeling floodplain extent, were simulated using the HEC-1 method that was also developed by USCOE. Its proprietary version, RGM HEC2000, was used for the project. The HEC-1 method uses available, site-specific atmospheric precipitation records of the given recurrence interval to calculate the streamflow rates based on the watershed topography, its soils, and vegetation coverage.

Work conducted at MSE of Butte, Montana, USA, was funded by the DOE Environmental Management Consolidated Business Center and performed at the Western Environmental Technology Office under DOE contract number DE-AC09--96EW96405.

REFERENCES

• 1: BOSS International. River Modeling System, User's Manual. 6300 University Avenue, Madison, WI 53562.
• 2: Chow, V. T.; D. R. Maidment; L. W. Mays. McGraw-Hill, Inc. 1988. Applied Hydrology.
• 3: NOAA's National Weather Services, Hydrometeorological Design Studies Center, "Precipitation Frequency Data Server," http://hdsc.nws.noaa.gov/hdsc/pfds/index.html.
• 4: Parsons. 1993. 100- and 500-Year Floodplain Determination Sitewide, CERCLA/RCRA Unit 2. Revision 0, dated September 1993 (100-Year Flood).
• 5: Parsons. 1995. 2,000-Year Flood and Probable Maximum Flood Sitewide Determination, Letter Report, CERCLA/RCRA Unit 2. Revision 0, dated November 1995 (2000-Year Flood).
• 6: U.S. Army Corps of Engineers. 2002. HEC-RAS River Analysis System-Users Manual. U.S. Army Corps of Engineers, Hydrologic Engineering Center, 609 Second Street, Davis, CA 95616.
• 7: U.S. Army Corps of Engineers. 1998. HEC-1 Flood Hydrograph Package-Users Manual. Hydrologic Engineering Center, U.S. Army Corps of Engineers, 609 Second Street, Davis, CA 95616.

INDEX TERMS

Keywords:
Fernald, HEC-RAS, RiverCAD, floodplain, surface water