干旱地区森林对流域径流的影响

森林对流域径流的影响包括森林对流域径流形成机制的影响、森林对流域径流量的调节以及森林对流域径流水质的影响3个方面。论文根据作者在黄土高原和北京土石山区多年研究的结果，并结合国内同行在森林水文方面的研究成果，就干旱地区森林对流域年总径流量、洪峰流量、枯水径流以及径流水质等方面的影响作了概括。结果表明，在干旱地区随着森林植被覆盖率的增加，流域年总径流量减少；森林植被可以大幅度地减小小流域的暴雨洪峰流量；森林植被覆盖率越高，枯水径流量随之增加；森林可以在很大程度上改善流域径流水质。根据干旱地区森林植被可以减少流域年径流总量的研究结果，初步估算目前我国干旱地区林业生态工程建设（包括天然林）的生态用水量为160亿m3左右。由于森林植被对流域径流影响的复杂性和尺度依赖性，森林在区域（或大流域）尺度的水文功能评价仍有待于进一步深入研究。

Impacts of forest vegetation on watershed runoff in dryland areas

Watershed runoff is impacted by forest vegetation in the ways of runoff generation mechanisms，total amount of stream flow，the temporal variations of annual runoff，and water quality of the runoff．This paper presents the authors and their colleagues research results carried out with this regards in dryland area throughout the world．The analyses show thatalong with the increase of forest coverage，the total annual volume of runoff could be reduced，the peak flow reduced dramatically in small spatial scaleswater quality of runoff improved to great extent．On the basis of research results， it was estimated that the water use for ecological sustainability is up to 16 billion m3 in terms of forestry ecological engineering in dryland area of China．Some future research chanlleges were also proposed in the last section of the paper．