Abstract
Run off characteristics of nutrients from small basins in Sigenobu river catchment area were invested in detail. These characteristics are summarized by using L-Q curve relationship, and first flush phenomenon in which nutrients concentration increased quickly during the early stage were observed in the cases of SS, T-P, PO4-P, and T-N. Detail observation was conducted in Yuwatari area in which urbanized area, citrus grove, and forest exist. SS and phosphorus concentration in discharged water increased with the increase of flow rate of discharged water, which means the pattern of the loading rate of SS and phosphorus was "washout type". Run of amounts of T-P and T-N were calculated and 84% of T-P, and 61% of T-N were discharged during rainy days. Management of catchment area in rainy days is more important than in fine days in the area.
