Board-Certified Water Resources Engineer DL Richards Consulting, LLC, Arizona, United States
Abstract Submission: Regime equations formulated by Gerald Lacey, Thomas Blench, and C.R. Neill may be used to predict general scour in alluvial channels. The regime equations calculate an average scoured depth, the depth measured between the water surface elevation and the average scoured bed elevation, for a channel considered to have attained equilibrium. The United States Bureau of Reclamation (BOR) published a technical guideline, “Computing Degradation and Local Scour,” which includes the equations and offers a procedure to convert the scoured depth to a depth of scour, the depth measured between the unscoured bed elevation and the scoured bed elevation. The BOR procedure determines the depth of scour by multiplying the average scoured depth by an empirical factor specified by the BOR to compute the depth of scour. However, the depth of scour computed by the BOR procedure differs from the depth of scour computed by a more “conventional” procedure. The presentation provides an evaluation of each procedure and offers findings on the different results obtained from the two different procedures.
