三川河流域近30年水土保持蓄水拦沙效益分析

根据黄河中游三川河流域至2000年的水文气象和水土保持措施量资料，分析了流域近30年降水、水沙变化特点和治理进展情况；通过水沙量还原计算，并在地表径流量推求和降水指标计算优选的基础上，建立汛期天然水沙量计算公式，进而计算分析出70年代以来各年代的蓄水拦沙效益。结果表明，该流域水土保持措施的蓄水拦沙效益十分显著，尤其是80年代蓄水、拦沙效益和90年代的拦沙效益分别较70年代提高了22．7％、18．4％和23．5％。

Benefit analysis of runoff storage and silt detention in the work of soil and water conservation in Sanchuan River Basin in recent 30 years

According to the meteorological and hydrologic al data and the used measures of soil and water conservation in the Sanchuan River Basin in the middle reaches of the Yellow River up to 2000, this paper analyzes the characteristics of precipitation, the changes of runoff and sediment, and the development of comprehensive harnessing in the recent 30 years. By using the reversal calculation of the amount of runoff and sediment,and based on deriving the surface runoff amount and choosing the rainfall index, the calculation formula for the natural amount of runoff and sediment in flood season was set up. The benefits of runoff storage and silt detention every decade from 1970s were calculated. The results showed that in the small watershed, the benefits of runoff storage and silt detention by adopting soil and water conservation measures were quite obvious, especially the benefits in 1980s and in 1990s increased by 22.7%,18.4%and 23.5% respectively than that in 1970 s.