Studies on the Sediment Distribution Property of the Guanting Reservoir Watershed for the Last Five Decades

Guanting reservoir (GR) is the second biggest reservoir in the Huabei district, north area of the China, it waters is the upper Yingdinghe river, composed of the sub-waters of Sangganhe river, Yanghe river and Guishuihe river. The watershed of GR is 43402 square kilometers (sq km), includes the area of Inner Mongolia, Shanxi province, Hebei province and Beijing city. Its storage capacity is 4.16 billion cubic meters, and the flood control volume is 2.99 billion cubic meters. Based on the investigating and monitoring of the sediment distribution in the watershed of GR, its results show that the total sediment yielding due to the soil and water loss in the GR watershed is 4.565 billion tons for the last five decades, among of them, soil and water conservation kept about 0.771 billion tons, it occupies 16.89% of total's amount. The water conservancy project retained about 0.765 billion tons, it occupies 16.76% of total's amount. The irrigation land deposited about 0.965 billion tons, it occupies 21.14% of the total's amount. The water course riverbed deposited about 0.816 billion tons, it occupies 17.88% of total's amount. The GR intercepted about 0.75 billion tons, it occupies 18.02% of total's amount. And the GR discharged about 0.425 billion tons, it occupies 9.31% of total's amount, respectively. According the statistics, to compare the sediment retention ratio of the soil and water conservation of the last twenty years, from 1981 to 2000, and the early thirty years, from 1950–1980, it increased about 26.27%.