不同地下水位埋深下五道沟地区地表径流变化规律分析

基于五道沟实验站1991~1999年实测降水、地表径流及地下水位埋深资料,运用水文学原理及数理统计方法,选取不同降雨量和降雨类型,分析了不同量级降雨量、前期土壤干湿状态、次降雨过程砂姜黑土地表径流量及径流系数随地下水位埋深的变化规律。结果表明,对于砂姜黑土,在50mm以上日降雨过程中,存在土壤表层蓄满、深部超渗的分层产流机制;地表径流量及径流系数随地下水位埋深增加呈指数递减趋势,且随降雨量的增加地表径流系数呈上升趋势;而前期土壤干旱时间长、土壤含水率较低、地表径流系数随地下水位埋深增加而减少,且降雨集中分布比降雨分散分布的地表径流系数高。

Analysis of Surface Runoff Variation under Different Depths of Groundwater Table in Wudaogou Area

Based on the measured rainfall, surface runoff and ground water depth data of Wudaogou station from 1991 to 1999, choosing different rainfall magnitudes and rainfall patterns, hydrology principle and mathematical statistics method are used to analyze the changes of surface runoff and its coefficient of the lime concretion black soil under different groundwater depths for the rainfall events with different runoff magnitudes and initial drought or wet conditions. The results show that there is a multi-layer runoff production mechanism that saturation excess runoff occurs in the shallow soil layer and infiltration excess runoff occurs in deep soil layer as rainfall amount is larger than 50 mm; amount of surface runoff and its coefficient exponentially decreases as the depth of groundwater table increases; meanwhile, surface runoff coefficient increases along with rainfall amount increase, surface runoff coefficient decreases if the soil endures a long period of drought and the depth of ground water table increases; the surface runoff coefficient is higher when a rainfall concentrated in a short period.