徐州城市供水水源地降落漏斗演变及成因分析

Analysis of evolution characteristics and formation mechanism of groundwater depression cone in water supply source area of Xuzhou City

徐州市岩溶水强烈开采形成明显的水位降落漏斗,引发了岩溶地面塌陷、地裂缝、地下水污染等一系列环境地质问题。通过对水源地水位降落漏斗形成演化的分析,得出研究区水位漏斗演化的3个阶段:增采阶段-水位下降(20世纪80年代)、控采阶段-水位平稳(20世纪90年代)、压/禁采阶段-水位回升(2000年以来);地表水资源缺乏、城市生活及工业发展过度依赖岩溶水,城市化面积增大、有效入渗补给量减小,矿坑疏干排水、增大岩溶水排泄量等为水位降落漏斗形成演化的主要影响因素;通过对岩溶水开采量、年平均降水量、土地硬化面积与漏斗水位进行多元相关分析,得出岩溶水开采量为岩溶水水位持续下降及漏斗形成与演变的主导因素。提出岩溶水超采情况下的水资源保障对策:控采岩溶水,制定不同管理目标下的地下水水位控制红线;修建水库、植树造林,扩大岩溶水水源涵养区;利用采空区修建地下水库等,实现地表水、地下水、矿井水及城市雨水的优化分配。

The intense exploitation of karst water in Xuzhou city formed the obvious groundwater depression cone and triggered the environmental geological issues, such as： land subsidence, karst ground collapse, and groundwater pollution.In this paper, the evolution characteristics and formation mechanism of karst groundwater depression cone were analyzed.The results show that the evolution of karst groundwater depression cones have three development stages： growth of exploitation-water levels fall （the 1980s）, control of exploitation-water levels stable （the 1990s）, suppression/forbidden of exploitation-water levels recovery （later than 2000）.The dominant influence factors of the evolution and formation are those which surface water resources are insufficient, city life and industry development completely rely on karst groundwater, urbanization area is expanded, effective infiltration recharge reduced, and mine drainage.Through the multiple correlation analysis for the cone water level with the karst water production, the average annual rainfall and land of hardening area, the paper concludes that karst water production for the water level of karst water continues to decline and funnel the leading factor in the formation and evolution.Furthermore, the water resources security countermeasures on karst water exploitation are put forward： reducing groundwater exploitation and making the water level control under different management goals, building reservoirs and afforestation to expand the scope of karst water, using mine-out area to build underground reservoir, which can implement optimal allocation of surface water, groundwater, mine water and urban rainwater.