Abstract
In the Hinuma River, the runoff characteristics of Chl-a as an indicator for algae were evaluated based on detailed observations during three and a half years. The higher the water temperature and the longer the days lasted after the last storm event were, the greater the Chl-a concentration during a low flow period. When the flow was increased by storm events, the Chl-a concentration became higher as the days lasted after the last storm event was extended. The algal biomass accounted for 13%, 23% and 7.8% of the particulate matter as carbon, nitrogen and phosphorus, respectively. Moreover, it was suggested that algae absorb and utilize 3.6% and 31% of dissolved nitrogen and phosphorus in terms of the annual runoff loading, respectively.
