Estimation of periphyton dynamics in a temperate catchment using a distributed nutrient-runoff model

This study develops a model to estimate the spatiotemporal distribution of stream algae on a basin scale by integrating an existing periphyton model into a distributed hydrothermal model to calculate the daily periphyton biomass throughout the Natori River basin. The influence of inorganic phosphorus on periphyton growth is incorporated into the periphyton model. The inorganic phosphorus concentration is simulated using the distributed pollute model depending on land use data to determine the phosphorus load. The model had a root mean square error (RMSE) = 14.1 mg/m² for periphyton biomass in the entire basin. This model shows that periphyton biomass tends to increase in the summer season with high water temperature and to decrease in the spring season with high discharge. This model can be applied to understand large spatial and temporal areas of the environment in a temperate catchment.