黄丘一区径流泥沙来源研究

<正> 一、黄丘一区径流泥沙来源 黄河是驰名世界居首位的多泥沙河流,年均径流量580亿m~3,年均输沙量16亿t,每年约有4亿t的粗泥沙淤积在下游河床。黄土高原严重的水土流失,是导致黄河下游河床不断淤积抬高的主要原因。钱宁、龚时旸等学者认为:黄河中上游43万km~2的水土流失区内,河口镇至龙门区间和华县、河津、(氵状)头以上的渭、汾、洛河支流26.6万km~2的区域,是黄河泥沙的主要产区,其沙量

Study on the Runoff and Sediment Coming From The First Loess Hilly-gullied Subregion

With the averange annual sediment delivery into the Yellow River of 590 million ton, the First Loess Hilly-gullied Subregion is one of main sediment sources for the Yellow River. It covers an area of 70700 km2, among that 51000 km2 contributing annual sediment delivery to the Yellow River of 419 million ton, includes Huangpuchuan, Wudinghe, Sanchuanhe, Kuyehe and Tuweihe basins arid is the main source of coarse sediment for the Yellow River. Within this subregion the area of the land between gillies accounts for 59. 4% of the total area, while the area occupied by gullies -40. 6%. On the Jiuyuangou and Wangji-agou small watersheds, 35. 3% and 37. 6% of the runoff coming from the land between gullies respective-ly, while 64. 7% and 62. 4% of the runoff from the gully land. For the Juiyuangou watershed, about 60% of the runoff and sediment coming from the slope farmland. Of all erosion forms the rill erosion is the most severe, contributing 45. 29% of the total soil loss. The soil loss is composed of as 53. 15% due to the sheet erosion (including rill erosion), 36. 85% from the gully erosion and 10% resulted by the gravity ero-sion.