HEC-RAS 1D Sediment Transport 1D Sediment Transport User's Manual Entering and Editing Sediment Data Initial Conditions and Transport Parameters Current: Fall Velocity Methods PDF Download PDF Download page Fall Velocity Methods. Current page All pages Fall Velocity Methods Several methods are available for computing fall velocity and the user should select the most appropriate algorithm. The options include:RubyToffaletiVan RijnDietrichReport 12 (Default method in HEC-6) ×