1问题的提出我国水土流失十分严重。1990年遥感普查结果表明：全国各类水土流失面积367×104km2，占国土面积的38％，而且人为破坏的水土流失仍以每年2×104km2的速度增加。严重的水土流失致使国土锐减，土地生产力大大降低，水质下降，江河湖库淤塞，水利水电工程效益难以正常 1 The issue of soil erosion in China is very serious. The results of the 1990 Census of Remote Sensing indicated that the area of ​​all types of soil and water loss in the country is 367 × 104km2, accounting for 38% of the total land area, and the water and soil loss caused by man-made damage is still increasing at the rate of 2 × 104km2 per year. Severe soil and water erosion caused sharp reduction of national territory, greatly reduced land productivity, water quality decline, siltation of rivers and lakes and reservoirs, and difficulties in normalizing the benefits of water conservancy and hydropower projects