小流域地下裂隙潜流对降雨入渗补给的响应特性

采用翻斗法自动量水技术和时域反射仪,对“岩土二元结构”小流域降雨过程、流域出口地下裂隙潜流以及坡地岩土水分的变化进行了测定与分析。试验结果表明,小流域坡地特有的岩土二元结构体具有较强的储、透水性能,小流域在前期坡地岩土水分平均为14.48%(埋深100cm范围内)的前提下,发生总降雨量170.25mm,降雨历时31h,平均强度5.5mmh的大暴雨,在小流域出口处未产生地表迳流;地下裂隙潜流对降雨具有明显的响应,起涨和回落过程均较为明显,峰值流量达到810Lh,是降雨前的32.4倍。因此,科学合理地利用“岩土二元结构”的水文地质特性对缓解洪峰的形成,降低洪灾具有重要作用,同时对山区的雨水资源化问题也具有重要的实际意义。

Fissure underground water responding to precipitation-infiltration recharge in small basins

By using the time domain reflection (TDR) and tipping bucket ombrometer, hydrological processes including rainfall infiltration into the soil, runoff, and base flow in a natural catchment characterized by a shallow soil layer and a deep stony layer of weathering gneiss during a rainfall event were monitored and analyzed. Before the rain event, the average soil moisture was 14.48% in the top 100cm soil layer. The rainfall event lasted for 31 hours and the total rainfall reached 170.25 mm, with an average intensity of 5.5mm per hour. Surface runoff was not observed for the whole event at all. However, base flow from the deep soil profile was rich. The peak of base flow was 810 liter per hour, which was 32.4times the level before the start of the rain event. The results suggest that the large amount of base flow in such kind of catchment conditions will be good for the rainfall harvest, since the structure of the soil profile is good to slow down the peak of the water discharge from the catchment.