With water collection area of 15 432 km2 within Qinghai province,Huangshui watershed is one of the main sediment yield region in the upper and middle Yellow River, from which 20.4 million tons of sediment is delivered into the Yellow River every year. Runoff is produced largely in the period of June to September each year in the watershed that makes up 53% of annual runoff yield; the area in the lower reach of the river makes up 41.1% of the total watershed,producing 42.4% of the annual runoff in total watershed.The area in the upper reach of the river accounts for 58.8% of the total watershed,but with only 21.6% of annual sediment yield of the watershed total.The sediment from the area of lower reach each year is 16 million tons,accounting for 78.4% of annual watershed total. There are frequent disastrous phenomenon in the watershed, rainfall and heat resources distribution not suitable for plant growth,which leads to degradation of vegetation in large areas.Beside natural disaster,frquent human economic activities are main reasons for severe soil and water loss in the lower reach areas.%湟水青海省境内面积15 342km2，是黄河中上游地区主要产沙区之一，年输入黄河泥沙2040万t。流域径流主要产生于6～9月，占年径流总量的53%；下游地区面积占流域总面积的41.2%，年径流量占流域年径流总量的42.4%。上游地区面积占全流域面积的58.8%，年输沙量仅占全流域年输沙量的21.6%；下游地区年输沙量1 600万t，占流域年输沙总量的78.4%。流域内灾害性天气频繁，水热配置不利于植物生长，大面积植被退化，人类经济活动频繁等，是导致下游地区水土流失严重的主要原因。
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