The Ohio River Community HEC-RAS model was developed by the U.S. National Weather Service (NWS), Ohio River Forecast Center (OHRFC) with cooperation from the U.S. Geological Survey (USGS), and U.S. Army Corps of Engineers (USACE). Initial planning to develop a community unsteady flow model for the mainstem of the Ohio River and major tributaries using the USACE HEC-RAS model began in late 2006. The purpose of collaborating on the development of the joint model was that, when completed, all cooperating agencies could independently use the model for operational/forecast and planning purposes.
While the Model is now complete, continued enhancements and extensions are anticipated, such as modeling reaches of major tributaries like the Cumberland and Kanawha Rivers. Subsequent changes by one agency will be passed back to the other agency in order to maintain consistency, so that future development can be easily shared. The scope of the modeling effort includes 20 locks and dams on the Ohio River, with storage areas and lateral structures such as levees, as well as bridges.
The Model is comprised of over 2800 cross-sections, spanning approximately 1300 miles of modeled reach. The downstream boundaries are Chester, IL for the upstream portion on the Mississippi River and Carruthersville, MO for the downstream portion on the Mississippi River. The upstream boundaries include Braddock Lock and Dam, WV on the Monongahela River and Natrona, PA on the Allegheny River. The Model requires lateral and tributary inflows and is run in real-time; for the OHRFC the lateral and tributary inflows result from runoff produced by both observed and forecasted precipitation. Laterally, Model cross-sections extend to the 500-year floodplain limits, except for Mississippi River reaches that only extend to the USACE levees.
Model development involved substantial geographic information system (GIS) data preparation to obtain consistent vertical and horizontal datums between the various data sets used. Digital elevation model (DEM) data sources included U.S. Geological Survey (USGS) 10 meter DEM, and Lidar data provided by the USACE, and local and state agencies. Bathymetric and in-channel cross-section data were provided by the USACE. Every effort was made to include the best available data, and. it is anticipated that substantial improvements will be made in the future by the use of higher resolution data sets.
This PDF document has more detailed information about HEC-RAS model and data.