Clear-water Scour Method Option

NCHRP 24-20 Method

For the NCHRP 24-20 Method, only the Laursen clear-water scour equation should be used.

SHA Modified Neill Method for Piedmont Zone

For the ABSCOUR Program, the program defaults to using Neill's method for the Piedmont Zone for clear water scour. This is the recommended method used by the Office of Structures. The User can also choose the Laursen's clear-water scour by selecting this option. See HEC-18 Chapter 6 for a discussion on the use and limitations of the Laursen clear water scour method. Please refer to the Users Manual for additional information, including an optional methodology for estimating scour in non-tidal wetlands similar to those in the Coastal Zone of North Carolina