PREDICTION OF ALGAL BIOMASS ON ARMORED RIVERBEDS AFTER CHANGE OF VERTICAL RIVERBED SURFACE BY SEDIMENT SUPPLY

Abstract

Riverbeds with sediment deficits and stable boulders are referred to as armored riverbeds. Sediment replenishment is one of the effective methods to resupply depleted sediment and detach algae that has overgrown on armored riverbeds. However, there are few methods available to predict algal biomass detachment when fine sediment is deposited after flooding, decreasing the area of exposed stone surface available for algae growth. Therefore, this study aimed to predict the algal biomass per unit area after sediment replenishment by creating a prediction model based on the relationship between sediment heights and exposed stone surface area. From the results, the model can be used to predict algal biomass per unit area. Furthermore, the results show that the flow patterns of sediment mainly depend on flow regime, but the patterns can be managed by altering the volume and location of the replenished sediment.