土地利用变化对东江流域产流过程影响的定量评估

Quantitative assessment on influence of land use change on process of runoff production in Dongjiang River Basin

基于SWAT(soil and water assessment tool)模型,对东江流域的水文过程进行了模拟,并分别采用1990年、2000年、2009年土地利用数据驱动模型,定量评价东江流域1990—2009年土地利用变化对流域水文过程产生的影响。结果表明:(1)流域出口月径流模拟率定期确定性系数R2为0.89,Nash-Sutcliffe效率系数ENS为0.87;验证期R2为0.88,ENS为0.87,东江流域SWAT模型径流模拟精度较高;近年来流域林地、草地面积减少,园地、城镇用地、水域面积增加。(2)在此影响下,东江流域单位面积侧向流降低了9.66 mm、基流降低了4.86 mm,地表径流增加了8.26 mm、实际蒸发增加了6.40 mm、潜在蒸发增加了4.40 mm;径流总量共减少了6.38 mm。(3)地表径流、侧向流对土地利用变化的响应在雨季更为敏感,实际蒸发、潜在蒸发及径流总量对土地利用变化的响应在旱季更为敏感。

The runoff process of Dongjiang River Basin was simulated based on SWAT（ soil and water assessment tool）,and the model was droved using different land use data of the year of 1990、2000 and 2009 to evaluated quantitatively the influence of land use change on the process of runoff production in Dongjiang River Basin. The results showed that（ 1） R2 and ENSof calibration and validation were（ 0. 89,0. 87） and（ 0. 88,0. 87）,respectively. SWAT model performed well in Dongjiang River basin. In recent years,the area of forest and grassland has reduced,while the area of garden land,urban land and water has increased.（ 2） Under the influence of this,sideward flow and base flow was decreased by 9. 66 mm and 4. 86 mm,respectively. The surface runoff,actual evaporation and potential evapotranspiration were increased by 8. 26 mm,6. 4 mm and 4. 4 mm,respectively. The total runoff was decreased by 6. 38 mm.（ 3） Surface runoff,sideward flow were more sensitive to land use change during rainy seasons,and actual evaporation,potential evapotranspiration and total runoff were more sensitive to land use change during dry seasons.