RUNOFF ANALYSIS OF SEDIMENT AND WATER DUE TO HEAVY RAIN FROM A MOUNTAIN RIVER DRAINAGE

A simulation method is developed to predict runoff of sediment and water from a mountain river drainage. The river drainage is divided into slope areas and river reaches. A kinematic wave method is employed in the runoff prediction from the slopes and a dynamic wave model for the runoff of sediment and water in the river reaches. Runoff of sediment and water from the slopes is considered at the slopes steeper than 6°, while runoff of water at the slopes milder than 6°. The result of the computation with the total-load transport equation agrees with the field measurements of sediment discharge in the Mizunashigawa River.