中文摘要：

峰丛洼地地区分布大量封闭洼地，暴雨过程中洼地内产生的地面径流通过落水洞进入岩溶管道，最终组成岩溶泉的一部分。本文选取典型的峰丛洼地地貌区——桂林丫吉试验场为研究区，通过修建径流小区监测地面径流量，结合示踪试验等手段探讨暴雨期间岩溶泉S31流量和水化学变化过程中这部分地面径流的作用。2010年径流小区监测结果显示当日降雨量大于64．4mm／d时研究区才产生地面径流，地面径流系数在O．48％-0．71％之间。选取5月19日降雨径流过程进行水均衡分析和离子质量守恒计算。S31泉域水均衡分析显示地面径流仅占S31泉总流量0．65％，不能显著影响S31泉流量变化。离子质量守恒模型结果表明暴雨期间S31泉电导率变化主要由裂隙水造成，虽然地面径流含有大量雨水，但对S31泉电导率影响有限。因地面径流的产生条件高和比例小，在适当降雨条件下可以忽略岩溶泉流量和水化学变化中地面径流的作用。

英文摘要：

Many closed depressions distribute in peak cluster area. The overland flow occurring in the closed depression enters the conduit though sink holes during storms and finally becomes a part of karst spring. In this paper, the typical peak cluster depression landscape-Yaji experimental site was selected to study the role of overland flow in discharge and hydrochemistry of karst spring though monitoring the quantity of overland flow and tracer experiment. The monitoring results of runoff plot show that overland flow occurred when rainfall was more than 64.4mm/day with low discharge in 2010. The overland flow coefficients were between 0.48% and 0.71%. The rainfall-runoff process of 19 May was chose to do water balance and ions mass conservation. Though the water balance analysis of catchment of Spring $31, overland flow only accounted for 0.63% of total discharge of spring. Overland flow could hardly influence the discharge of karst spring. The results of ions mass conversation model show that the variation of electrical conductivity of spring $31 was caused mainly by fracture water. The overland flow contains abundant rainwater, but the effect to electrical conductivity is very limited. Because of high rainfall needs and low proportion of overland flow, we can ignore the impact of overland flow on the variation of discharge and hydrochemistry of karst spring under appropriate rainfall conditions.