广西岩溶水资源与社会服务功能

Karst Water Resources in Guangxi and Their Social Servicing Capacity

关键词:  广西  岩溶  水资源  水源地  地下空间

Key words:  Guangxi  karst  water resources  water sources  underground space

摘要:

广西岩溶分布广泛且类型多样，岩溶水资源普遍服务于农业生产、城市与农村供水，或应对极端气候产生的干旱等。认清水资源的形成、演变趋势和动力机制，能使其更好地发挥社会服务功能。本文以广西5个具有长期研究积累的岩溶场地为例，采用地下水分层观测技术展示了表层岩溶带的调蓄过程，提出表层富水带可以成为石漠化治理和缓解干旱的找水方向；设计洞穴滴水观测装置，展示了渗流通过包气带的过程，提出干旱和内涝的地质成因；建立洞穴交互带的观测方法，展示地下水与地表水的交互过程，指出地下水与地表水交互作用成为水源地环境退化的驱动力；建立地下河的氮流失模型，显示农业活动引起的氮流失过程，总结地下河系统中氮的循环机制并提出固氮方案；建立地下水潜蚀作用的观测方法，展示潜蚀作用的机制，提出城市地下空间的保护和利用需要综合考虑水动力侵蚀和化学溶蚀。岩溶地区水资源与水环境问题的认识需要结合岩溶水的补给、下渗、径流、排泄过程的观测，揭示问题产生的机制，实现岩溶水资源的可持续利用。

Abstract:

The karsts in Guangxi are widely distributed and diverse,and karst water resources generally serve for agricultural production,urban and rural water supply,or droughts caused by extreme weather. Recognizing the formation,evolutionary trends and dynamic mechanisms of water resources will enable them to better play their social service functions. In this paper,five karst sites with long-term research and accumulation in Guangxi were taken as an example. The groundwater stratification observation technology was used to demonstrate the regulation and storage process of the epikarst zone. It was proposed that the surface water-rich zone could be used to control the rocky desertification and ease the drought. A cave drip observation device was designed to demonstrate the process of seepage through the vadose zone and present the geological origin of drought and water logging. The observation method of establishing a cave interaction zone was used to show the interaction process between groundwater and surface water,and to point out that the interaction between groundwater and surface water becomes the driving force of environmental degradation of the water source. A nitrogen loss model of the underground river was established to show the nitrogen loss process caused by agricultural activities. The nitrogen circulation mechanism in the underground river system was summarized and a nitrogen fixation scheme was proposed. The observation method of groundwater erosion was established to demonstrate the mechanism of erosion. It was proposed that the protection and utilization of urban underground space required comprehensive consideration of hydrodynamic erosion and chemical dissolution. The understanding of water resources and water environment problems in karst areas needed to be combined with the observation of karst water recharge,infiltration,runoff,and discharge processes to reveal the mechanism of problem generation and to realize the sustainable utilization of karst water resources.