基于SWAT模型的长江源土地利用/土地覆被情景变化对径流影响研究

土地利用/土地覆被变化对流域水资源循环过程及配置影响显著。为了研究土地利用/土地覆被情景变化对径流影响情况,以长江源流域为例,构建了适合该流域的分布式水文模型(SWAT),并模拟了不同土地利用/土地覆被情景下的流域年均径流量和径流深。模拟结果如下:当流域林地和草地面积增加到最大,径流量减少了16.7%,达到304.12m3/s,径流深减少14.02mm;当林地和草地面积减少,并逐步变为沙地、裸地,流域径流量增加16.1%,达到424.32m3/s,径流深也增加了13.49mm;当林地和草地面积减少到无植被覆盖,将使流域径流量增加28.4%,达到469.67m3/s,径流深增加23.88mm;在草地覆被最佳状况下,径流量有所增加,但增加幅度不大,只有5.6%,达到385.98m3/s,径流深增加4.72mm。综上所述,长江源流域林地和草地面积增加,导致径流减少,而沙地和裸地面积增加导致径流量增加。

SWAT Model of Runoff Study under Different Land Use Land Cover Scenarios in Source Region of the Yangtze River

Land use and land cover change play an important role in catchment hydrology cycle.In order to analyze the hydrology effect caused by land use and land cover change,runoff and depth of runoff in the source region of the Yangtze River basin was estimated based on land use and land cover scenarios and SWAT model.The result showed: runoff decreased 16.7% with 304.12 m3/s and depth of runoff decreased 14.02 mm under the situation of forest and grass land covering whole area of the basin;runoff increased 16.1% with 424.32 m3/s and depth of runoff increased 13.49 mm when the forest and grass land area changed into sand and bare land;runoff and depth of runoff increased most when there were no forest and grass land,the runoff reached to 469.67 m3/s,increased 28.4%,depth of runoff increased 23.88 mm;there was a little increase of forest and grass land growing perfectly,runoff and depth of runoff increased 5.6% and 4.72 mm.It is obvious that increase of forestland and grassland made the runoff decrease and the increase of sand and bare land led to rise of runoff.