Hydrogeochemical analysis of Wujiaying karst ground-water system boundaries,Kunming

In Southwest China,the hydaulic boundaries of the karst groundwater system are very complex, partly because the water-resisting property of the constant-head (Type Boundary)is unstable.In this paper, Wujiaying karst groundwater system in Kunming is studied.Three methods have been used to study the hydrogeochemistry and hydrogeological boundaries,i.e.dynamic groundwater chemical analysis,mathemati-cal statistics and hydrogeochemical modeling.The results confirm that the groundwater flow in this area is more active and may link to other groundwater system in wet season.Due to the high hydraulic head differ-ence,groundwater in the karst valley area can be driven to pass through the karst aquifer under the confining bed and recharge the Wujiaying karst groundwater system via leakage.While in dry season,this type of hy-draulic connection is not common.It is concluded that the water-resisting property of this type of boundary could have dynamic response to the change of the hydraulic condition in the karst groundwater system.This research has significant value in the context of local groundwater resource evaluation and sustainable develop-ment.