大通河流域土地利用/覆被变化的水文响应

以大通河流域为研究区域，利用1985年和2005年土地利用数据，结合SWAT分布式水文模型定量评估了流域土地利用/覆被变化的水文效应。结果表明：1985-2005年大通河流域的土地利用变化主要表现为草地向耕地、居工地转变，草地所占比例由46.7%骤降至20.9%，而耕地面积由1985年的1065.8km²增加到2005年的3243km²；相较于1985年的土地利用情景，2005年土地利用情景下的模拟的多年平均径流增加了1.92×10⁸m³，由于上中下游主要的土地利用/覆被变化不同，导致流域径流变化增加程度由西北至东南逐渐增大；大通河流域年径流的增加主要表现为汛期径流增加，讯期月平均径流增幅达到了0.40×10⁸m³·mon^-1；非汛期径流则呈不明显减小趋势，平均降幅为0.024×10⁸m³·mon^-1。合理规划大通河流域土地利用方式，提高水源区涵养能力，对流域水资源可持续发展具有重要意义。

Hydrological response to land-use/cover change in the Datong River

Taking Datong River basin as a study area,using SWAT model,the hydrological effects in the basin was quantitatively analyzed based on the land-use/cover change scenarios in 1985 and in 2005.The results showed that:(1) during 1985-2005,the most evident change of land-use was grassland shifting to farmland and construction sites.As a result,the grassland proportion greatly reduced,from 46.7％ to 20.9％,and the cultivated land area from 1 065.8 km in 1985 increased to 3 243 km in 2005;(2) compared with the land-use situation in 1985,the simulated multi-year average runoff of 2005 increased 1.92 × 108 m,with the increasing gradually from northwest to southeast due to the different in main land-use among the upstream,midstream and downstream;(3) annual runoff increase was mainly in the flood season,with a rate of 0.40 × 108 m · mon-1,while in non-flood-season runoff decreased with a rate of 0.024 × 108 m · mon-1 Therefore,it is of great importance to make reasonable land-use plan and to improve the ability to conserve water resources for sustainable development in the basin.