Study on the Flood Volume Investigation for Medium and Small River

The hydrological research of ungauged basins became the new topic of international hydrological plan, the flood investigation can effectively make up for the information insufficient of the contemporary remote sensing technology and traditional statistical interpolation techniques. Take Dasha River rainstorm for example, water surface slope was monitored of 8‰ by slope-area method, the peak flow was calculated of 1830 m3/s. According to the measured multi-peak flood hydrograph simulates single peak hydrograph and five points probable, the flood volume was calculated of 109 million m3, the runoff coefficient is 0.84 and runoff depth is 505 mm. The river basin has 250 mm previous rainfall, and the underlying surface was saturated, so the result indicated that it accord with runoff yield and concentration theory. The method can be extended for medium and small size river.