喀斯特峰丛-洼地小流域洪水滞时及相似性分析

以两个邻近的典型喀斯特峰丛-洼地小流域(陈旗和长冲)为研究对象,选取26场不同量级流量的洪水过程,对比分析陈旗流域地表、地下两套水系及其与长冲流域洪水的滞时和相似性特征。结果表明:陈旗流域受洼地不透水/弱透水跃迁部位的"门槛效应"影响,地表河与地下河的洪水滞时和形态特征差异明显,地表河洪水涨落迅速,但峰现时间滞后于地下河;流域暴雨洪水涨落形态受地表河控制,与地表河洪水形态相似度高。长冲流域暴雨洪水过程与地表洪水过程相似,随着降雨量的减小,其洪水形态趋向于地下河径流变化特征;流域不透水岩石分布减小了含水层调蓄能力,流域洪水滞留时间短、暴雨洪水响应迅速。

Analysis of flood lag time and similarity in small karst peak cluster-depression watersheds

Two small adjacent typical karst peak cluster-depression watersheds(Chenqi and Changchong)were chosen as the research objects, and then 26 flood processes with different magnitudes of flow were selected. The characteristics of the lag time and similarity of the surface and subsurface runoff in Chenqi watershed were compared and analyzed with those in Changchong watershed. The results show that due to the soluble rock of the depression and the threshold effect of the impervious or weakly permeable transition at the Chenqi watershed, the characteristics of the lag time and similarity between the surface and underground runoff show obvious differences. The surface runoff fluctuates more rapidly but its peak time lags behind that of the underground runoff. The flood fluctuation shape of the watershed is controlled by the surface river and it has high similarity with the flood process of the surface river. The flood process in the Changchong watershed is similar to the surface river flood process, and as the rainfall decreases, the flood shape tends to change the characteristics of the underground river runoff. The distribution of impervious rocks in the watershed reduces the aquifer''s ability to regulate storage. The flood lag time in the watershed is short and the runoff responds quickly to the rainfall.