LIU Ji-gen ¨C LIU Jian-hua ¨C SUN Hou-cai
(Changjiang River Scientific Research Institute, Changjiang Water Resources Commission, Wuhan 430010, China)
Abstract:Research on drainage basin erosion and sediment yield amount is not only an important task in physiognomy, but also an important one in river harnessing and water conservancy. This paper tries to conducted an integrated analysis of the effect of rainfall, runoff and physiognomic forms on drainage basin sediment yield, on the basis of considering sediment yield mechanism and to establish sediment yield formula for single rainstorm in Chabagou drainage basin which will have a certain sediment yield mechanism. Through integrated analysis of the effect of rainfall, runoff and physiognomic factors on sediment yield, we can find that as for the effect of rainfall amount and its temporal and spatial changes on drainage basin sediment, the correlation coefficient of rainfall amount and rainfall intensity product PI with drainage basin sediment yield modulus Ms is the highest. But when we consider rainfall runoff effect on drainage basin sediment yield, rainfall action has become. The effect negligible, the main factors affecting sediment yield are runoff depth H and flood peak discharge Qw of runoff depth H on sediment yield is essential, but its effect on sediment yield of different scales of drainage basins is the same. Flood peak discharge Qw is mainly accountable for the remarkable difference in sediment on yield of drainage basins of different scales. With the increase of area, the effect of flood peak discharge Qw drainage basin sediment yield also weakens. Of the physiognomic factors, drainage basin area and ravine density play the leading role, and drainage basin channel gradient ratio is on the comparatively secondary position.
Key words: Drainage basin sediment yield; Rainfall factors; Runoff factors; Physiognomic factors; Statistical models