Abstract:

In order to avoid drawbacks existing in mapping specific sediment yield using direct interpolation of measured sediment load data at hydrological stations,this study takes the sediment erosion as a weight in interpolating the specific sediment yield.Using this method,a map of specific sediment yield in the upper Yangtze River is made from the records of sediment load at 152 hydrological stations in the period from 1956 to 1987 and other relevant data.Some of the records of sediment load are interpolated for making them comparable between stations.The results of cross validation show that the method advanced by this study is better than the direct interpolation method in spatially interpolating specific sediment yield.The map of specific sediment yield produced by this study reveals that two high sediment yield belts exist in the upper Yangtze River,one of which extends southward from the south Gansu to mountains in middle Sichuan and Yunnan Provinces,and the other spreads southeastward from Qinglin and Daba mountains,through hilly areas in the north middle Sichuan,to the Huangling anticline.Also,it is shown that there are local spots or strips of high sediment yield in areas with low sediment yield and verse visa,reflecting the highly spatial variability of sediment yield in the upper Yangtze River.