Energy dissipation on block ramps with large scale roughness

Abstract

Block ramps represent a steep sloped short section of a channel provided with large roughness and used as grade stabilization structures. Experimental study on block ramp with macro roughness has been carried out in this paper for studying the water surface profile over the ramp and also for quantification of energy loss. Measured water surface profiles over ramps of various slopes reveal that steeper slope is reigned mainly by non-uniform flow, however, uniform flow occurs on major part of the ramps for relatively less steeper slopes. The energy dissipation over block ramp with large roughness is more for higher size of the boulders. The energy dissipation computed using existing equation is in good agreement for low slope (1V:9.87H), while it deviates from the observed values for higher slopes (1V:6H) and (1V:3H). Energy dissipation per unit length of the ramp increases with increase in the ramp slope.