Analysis of Cause for Water and Sediment Variation in Yangjiagou Watershed

摘要

Yangjiagou, a tributary gulley in Nanxiaohegou watershed, was determined as a pilot area for small watershed management in 1954. It was aimed to study the effect of soil and water conservation measures on runoff and sediment yield in small watershed by contrast with uncontrolled Dongzhuanggou watershed. Through continual regulation, retention benefit achieved by the soil and water conservation measures played a dramatic role. Analysis of measured data shows that both flood and sediment in Yangjiagou watershed has been on significant rise since the 1980s. This paper makes an analysis of the causes of water and sediment variation in Yangjiagou watershed from the angle of the number and service life of soil and water conservation measures, and draws a conclusion that water and sediment increase in Yangjiagou watershed arises from two factors: first, there has been a slowdown in the number of soil and water conservation measures that play an important role in water and sediment retention; second, the service life of gulley control works that yield great returns in soil and water conservation is limited.