For the water quality management in wide area of a river course, quantitative evaluation for the processes of sediment transport and nutrient lord is very important Present study is focused on the contamination load in a flooding river. The investigation performed by the observation of seven times of a flood in Abukumagawa River. And, the processes of nutrient load and transportation were evaluated by the numerical model based on a mass loading rate and the channel network system using kinematic-wave method.
