千岛湖地区封山育林水源涵养效益

The Benefit of Closing Hillsides to Facilitate Afforestation to Conservation of Water Supply in Qiandao Lake's Region

经采用面上样地调查和设置迳流观测场相结合的方法进行调研,定量评估千岛湖地区封山育林水源涵养效益。结果表明:1.有林地比无林地年有效持水量大30％,20年累计10亿m^3,起到削减洪峰及调节水源的巨大作用。2.有林地比开垦地地表迳流系数小53％,输沙率减少99.1％,起到明显的保持水土作用,减缓水库淤积,延长水库使用年限。3.封山育林提高了水库水质的纯洁度和透明度,防止水库污染,提高了千岛湖的景观价值。

Xin'anjiang exploiting Company has carried out closing hillsides to facilitate afforestation about 22 500 ha since 1950. After thorough approaches of combinating sample plot survey with building runoff observing yield some researches were carried to quantitatively evaluate the ecological benefit of closing hillsides to facilitate afforestation on water conservation. Some results showed that: 1. The annual effective water capacity of forest land is 30% larger than that of barren hills, total store water is about a billion cubic metres in 20 years, so that the forest land has a great effect on decreasing the peak of flood and regulating the supply of water; 2. The runoff coefficent of soil surface of forest land is 53% less than that of clearage, and the rate of transporting sand is lower 99.1%, so that closing hillsides to facilitate afforestation has a great contribution to conserving water and soil, decreasing the acceretion of reservoir and prolonging the life of reservoir; 3. The closed forest has improved the degree of purity and transparency of the reservoir water, and prevented its pollution. The landscape value of Qiandao Lake has thus increased.