通过定位监测和样品跟踪采集,在旱季对喀斯特小流域连续20天无前期降雨的一场暴雨(累计降雨量64mm)水文水化学过程进行了动态监测,并分析了相关的影响因素。结果表明,小降雨事件(8.5mm)未能引起溪流水位、电导率及温度的明显变化,而当累计降雨量达到35.5mm后溪流水开始响应。此后,溪流水文水化学参数对降雨快速响应,除硝态氮外,电导率(EC)、δ18 O、Ca2+迅速降至最低值,雨水稀释作用对其水化学变化起主要作用。通过对溪流新旧水比例进行划分发现,降雨前期和后期,溪流以旧水补给为主,而在水位快速上涨阶段,新水比例达到34%左右。两次降雨过程中,在溪流水水位升高的情况下,水体中硝态氮浓度仍然表现出高于雨前浓度的趋势。该研究为该区旱季小流域水资源利用和污染物防治方面提供了一定理论依据。 Through the process of location monitoring and sample tracking, the hydrological and chemical processes of a rainstorm (accumulated rainfall 64mm) without any previous rainfall in the karst small watershed for 20 consecutive days in the dry season were monitored dynamically and the related factors were analyzed. The results showed that the small rainfall event (8.5mm) did not cause significant changes in water level, conductivity and temperature of the stream, but the stream water began to respond when the accumulated rainfall reached 35.5mm. Since then, the chemical parameters of stream hydrology and water responded quickly to rainfall. In addition to nitrate nitrogen, the conductivity (EC), δ18O and Ca2 + rapidly decreased to the lowest values, and the dilution effect of rainwater played a major role in the chemical alteration of water. By dividing the proportion of old and new streams in the stream, it is found that the streams are dominated by old water during the early and late rains, while the proportion of fresh water reaches about 34% during the period of rapid water level rise. During the two rains, the concentration of nitrate nitrogen in the water body still showed a trend higher than that before the rain when the water level of the stream water increased. The study provides a theoretical basis for the utilization of water resources and prevention and control of pollutants in the small watershed in the dry season.