关键词: 流域产沙, 降雨因子, 径流因子, 地貌因子, 统计模型

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 construction. Drainage basin runoff and sediment formation is a very complex physical process. The fundamental reason for it is the result of rainfall and drainage basin underlying horizon reciprocity. Mathematically, it is an altitudinal nonlinear mapping relation from drainage basin underlying horizon and rainfall conditions to drainage basin runoff and sediment transport. The structure of drainage basin sediment yield statistical models is simple, convenient to calculation and serves as a power tool available for sediment yield prediction. Many researchers according to their study region and measures, established different empirical statistical models. Although so many empirical statistical models were set up, the factors they considered were not the same. 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. It is also hopefully to offer some references for other researchers in establishing drainage basin statistical models. 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 M s is the highest. But when we consider rainfall runoff effect on drainage basin sediment yield, rainfall action has become negligible, the main factors affecting sediment yield are runoff depth H and flood peak discharge Q W. The effect 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 Q W is mainly accountable for the remarkable difference in sediment yield of drainage basins of different scales. With the increase of area, the effect of flood peak discharge Q W on 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