西延河流域位于我县南村乡境内,是全县75条大沟之一。南临黄河,北靠中条山,属黄河一级支流。主沟长15.5公里,上游为荒山秃岭,中下游为黄土残塬沟壑区,总面积6.5万亩。流域内有支毛沟118条,水土流失面积占92％。地形北高南低,纵坡较大,支离破碎,植被稀少,水土流失严重。每年流入黄河的泥沙量达30多万吨,土壤侵蚀模 West Yan River Basin is located in the county village of South Village, is one of the 75 major ditch. South of the Yellow River, north of the Strip, a tributary of the Yellow River. The main trench is 15.5 kilometers long. The upper reaches are bald patches of barren hills. The middle and lower reaches are gully areas of loess plateau with a total area of ​​65,000 mu. There are 118 furcobs in the basin, accounting for 92% of the area of ​​soil erosion. The terrain is high in the north and low in the south, with a large longitudinal slope, fragmented, scarce vegetation and serious soil erosion. Each year the amount of sediment flowing into the Yellow River reaches more than 300,000 tons, and the soil erosion mode