| Sediment replenishment at downstream reaches of a dam restricts algal biomass not only by detaching algae on riverbed materials, but also by covering exposed area of stones where algae can attach and grow. In this study, we developed a model for estimating a ratio of the exposed area (R) assuming that the area of exposed stone surface depends on the height of sediment deposition relative to the height of the stone surface. Then, algal biomass per square meter was calculated as the product of R multiplied by algal biomass. Further, accuracy of the model was confirmed based on the results of experiment in the artificial rivers in Gifu Prefecture, Japan. The results showedthat estimated values of the model were generally consistent with measured values of the experiment. |
