CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Akhmedov, T.H.
Date : 1988
Title : Calculation of the depth of scour in rock downstream of a spillway
Publication : International Water Power and Dam Construction
Issue : 40(12):
Page(s) : 25-37
Abstract
A method is described for determining the depth of river bed scouring caused by spillway discharge and it is applied at two sites, Tarbela Dam, Pakistan, and on the Stikine River, Canada. Initially, flow volume will break off fragments of rock. As scour pit depth increases, the flow velocity near the bed decreases, until a point is reached when this form of erosion ceases. The development of the scour pit is divided into three phases: (1) direct removal of rock fragments, (2) dislodgement of rock fragments under hydrodynamic forces, and (3) grinding of loose rocks against each other with the smaller ones being carried away by the flow (abrasive phase). At the Tarbela Dam, where rocks are metamorphosed limestones, the difference between the actual and the calculated scour depth ranged from -4.53 to 23.8%. Comparable figures for the Stikine River were -40.6 to 34.5%. (Negative values mean that calculated values exceeded actual values.)
Bibliography of Canadian Geomorphology