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(一)水资源概况安塞县位于延河上游,面积2650平方公里,其中延河水系面积占60％,有杏子河和西川河两支流。境内沟道约有1850条,沟壑密度为4.6～5.8公里/平方公里,川道一般宽约0.5～1.0公里,两岸川台地高于河床10～20米,适宜发展灌溉。该区年平均雨量500～600毫米,蒸发量1100～1300毫米,干旱指数为2～2.66。全县属黄土高原重点水土流失区,侵蚀模数达
(A) Overview of Water Resources Ansai County is located in the upper reaches of Yanhe, an area of 2650 square kilometers, of which Yan River area of 60%, there are apricot and Xichuan River tributaries. About 1850 domestic channels, gully density of 4.6 ~ 5.8 km / km2, Sichuan Road generally 0.5 ~ 1.0 km wide, cross the Taiwan River Plateau 10 to 20 meters above the riverbed, suitable for the development of irrigation. The average annual rainfall of 500 ~ 600 mm, evaporation 1100 ~ 1300 mm, drought index of 2 ~ 2.66. The county belongs to the key soil and water loss area of the Loess Plateau, erosion modulus up