黄土高原泾河流域梯田对河道径流及生态基流影响

Effects of Terrace on Runoff and Ecological Base Flow of Jinghe Watershed in Loess Plateau Region

[目的]定量分析泾河流域梯田建设对河道径流、生态基流的影响程度,为流域梯田建设提供一定理论支撑。[方法]采用合作开发的嵌入梯田模块的SWAT(soil and water assessment tool)模型模拟河道径流量。[结果]嵌入梯田模块的SWAT模型在模拟河道径流时可满足模型模拟精度的要求;随着梯田面积增加,河道年径流量减少,生态基流保障程度提高,年、月生态基流不满足天数降低;梯田的年平均减流量为4.25×104 m3/(km2·a);梯田具有蓄洪补枯作用,且对丰水期的调控效果高于枯水期,对河道生态基流的影响为:枯水期>平水期>丰水期。[结论]嵌入梯田模块的SWAT模型在该流域具有较好的适用性,提高流域内梯田面积是滞洪补枯的有效手段之一,在一定程度上保障了河道生态基流。

[Objective]The objective of this study is to quantitatively analyze the effects of terrace on river runoff and ecological basic flow（EBF）of Jinghe watershed in Loess Plateau region,to provide theoretical supports for construction of terraces in the watershed.[Methods]The process-based terrace algorithm was developed based on soil and water assessment tool（SWAT）model to simulate river runoff.[Results]The developed model satisfied the accuracy requirements in runoff simulation.With the increase of terrace area,annual runoff and number of days when runoff less than EBF were reduced,and the security level of EBF enhanced dramatically.Terrace could reduce runoff by as much as 4.25×104 m3/（km2·a）.Moreover,terrace could adjust the flood and runoff,and this adjustment effect on runoff in wet season was higher than that in dry seasonThe effects of terrace on EBF showed as：dry season〉the normal season〉the wet season.[Conclusion]The newly developed terrace algorithm is satisfactory in simulating daily runoff in Jinghe watershed.Increasing terraced area is an effective way to adjust runoff in both wet and dry seasons,and guarantee EBF.