Stream bed Condition Correction Factor K3

Refer to the FHWA Manual HEC-18 for a discussion of the stream bed conditions associated with typical flood flows frequencies used for estimating pier scour.

Clear-water scour: K3=1.1
Plane bed and Antidune Flow: K3=1.1
Small dune (dune height 10'>H>2') (3m>H>0.6m): K3=1.1
Medium dune: (dune height 30'>H>10') (9m>H>3m): K3=1.1 to 1.2 (program use 1.2)
Large dune: (dune height H>30') (H>9m): K3=1.3