HEC-RAS 2.2 for backwater and scour analysis - phase one

The Kansas Department of Transportation (KDOT) and most bridge consultants in Kansas have been using the DOS-WSPRO program and the KDOT scour spreadsheets to perform bridge hydraulics and scour analysis for the past several years. Unfortunately, DOS-WSPRO is a DOS program that is no longer supported and there is no metric version. Consequently, the newer Windows-based hydraulics program HEC-RAS (Hydrologic Engineering Center River Analysis System) developed by the U.S. Army Corps of Engineers appears to be a logical choice to succeed DOS-WSPRO as the basic flow model in KDOT's bridge design and scour analysis program. HEC-RAS has gained considerable popularity in the engineering community and offers many options not previously available to hydraulic modelers. It also has a scour module and has an option, the WSPRO bridge analysis routine (henceforth called HR-WSPRO). This study compared the HEC-RAS program with the DOS-WSPRO program and examined the HEC-RAS program with regard to scour analysis. The possibility of using the existing KDOT scour spreadsheets with output from the HR-WSPRO bridge routine was also considered. Finally, a literature review was performed to determine if any updates in the scour methods and new approaches to special conditions, such as the effect of debris or pressure flow affecting pier scour, were available.