Hydraulic Optimization of River Sub-Channels for Sediment Reduction and Pump Protection under Low Discharge Conditions: A Literature Review

Sediment-laden flow remains a major source of hydraulic efficiency reduction, deposition, clogging and wear in pumps, intakes, forebays and turbomachinery, especially during low flow conditions, in which uneven flow structures and local sediment deposition are exacerbated. This paper reviews the state of knowledge on hydraulic measurement and control to mitigate sediment problems and protect pumps, principally through geometric redesign, sediment-exclusion devices, numerical and physical modelling, turbomachinery erosion, smart control, and sediment properties. The literature indicates that geometric changes to intake channels, forebays, areas near pumps, and river sub-channels can increase flow uniformity and eliminate sediment deposition areas. Sediment exclusion structures consisting of submerged vanes, baffles, rectification devices, and overflow reservoirs also contribute to pump/forebay protection, but depend on hydraulic and geometric conditions for effectiveness. Numerical and experimental methods, particularly integrated CFD and physical model analysis, are the primary source of information for assessing design performance and erosion potential. In summary, the literature suggests that sediment control and pump protection constitute an integrated systems challenge involving interactions between hydraulic geometry, sediment transport, erosion control and system operation. Additional advancements require more standardised, validated and holistic approaches.