Block ramps for stream power attenuation in gravel-bed streams: a review

Abstract

Application of the block ramp technique in steep gradient streams for energy dissipation as well as to maintain river stability finds increasing favor amongst researchers and practitioners in river engineering. This paper dwells on a comprehensive state-of-the-art review of flow resistance, energy dissipation, flow characteristics, stability, and drag force on block ramps by various investigators in the past. The forms and equations for each type are thoroughly discussed with the objective of finding the grey areas and gaps. More research is warranted further to improve the equations, which are essential for design analysis. Block ramps can be a promising simple technique to achieve reasonable attenuation of devastating fluvial forces unleashed in gravel-bed streams during cloud bursts. HIGHLIGHTS A critical review of recent advancement in flow resistance, energy dissipation, flow characteristics, stability and drag forces on block ramps.; Highlights the grey areas and gaps.; Need for 3D turbulent burst analysis for better understanding of the internal mechanism of turbulent structures.; Application of all the equations in design with limitations and suggestions for improvement are well discussed.; Formulation of block ramps is based on steady flow assumption but in reality flows are highly turbulent with unsteady flow in mountain streams.;

Keywords

• block ramp
• drag force
• energy dissipation flow resistance
• stability