美国大流域长时间序列水土保持减沙效果分析

Analysis and research on effects of sediment reduction through soil and water conservation in large river basins in USA

为借鉴美国开发治理比较早的一些河流的经验教训，选择密苏里河上游的Willow、佐治亚州Uoya Shoals水库、韦科、田纳西河一级支流渡科河、科罗拉多河上游等5条较大的流域进行水土保持减沙效果分析。通过前后长达10-32年的大流域、长时间序列的水土流失治理，在排除降雨和水利工程影响的因素，其下游河道减沙效果都很显著，减沙分别在38％-55％之间。

In order to use experiences and lessons of earlier river management and soil and water conservation in USA for references, 5 large river basins have been selected in this paper to study effects of sediment reduction contributed by soil and water conservation practices. The five river basins include WiUos stream of upper Missouri river, Lloyd Shoals Reservoir watershed, Lake Waco watershed, Duck river watershed of Tennessee River basin, upper Colorado River basin. Excluding the factors of rainfall and water conservancy project construction, the analysis results show that the sediment reduction effects of soil and water conservation practices in these basins are very obvious in the contrast analysis between 10 to 32 years, sediment reduction rates of these basins ranges from 38 % to 55 %.