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大理河是无定河的一条主要支流,全长170公里,流域面积3906平方公里。该流域地处黄土丘陵沟壑区,地形破碎,植被稀疏,水土流失严重。据1960～1970年统计,多年平均降水量为478毫米,年径流量为1.82亿立米,年输沙量6540万吨,平均年侵蚀模数为1.68万吨/平方公里,局部地区高达每平方公里3万吨。该流域1954年开始水文观测,1959～1969年在流域内进行过大面积径流实验,为分析流
Dali River is a major tributary of Wuding River, a total length of 170 km, the basin area of 3906 square kilometers. The basin is located in loess hilly and gully area, the terrain is broken, vegetation is sparse, soil erosion is serious. According to the statistics from 1960 to 1970, the average annual precipitation is 478 millimeters, the annual runoff is 182 million cubic meters, the annual sediment discharge is 65.4 million tons, the average annual erosion modulus is 16,800 tons / square kilometer, and in some areas up to a kilometer per square kilometer 30,000 tons. The basin started hydrological observation in 1954 and large-scale runoff experiments were conducted in the basin from 1959 to 1969. In order to analyze the flow