岩溶洞穴交互带概念的提出及其在水资源管理中的意义

岩溶地区以管道流为主的地下水补给、径流与排泄常常引起地下水与地表水间快速且频繁的交互与转化，并因此引发水环境退化问题。文章引用并拓展地表水文学和水文生态学中交互带的概念，提出南方岩溶地区管道流与其他类型水体交互的场所为岩溶洞穴交互带，并依据交互带的水流类型和交互方式，划分为泉口交互带、天窗交互带、落水洞交互带和管道交互带4种类型；且以泉口交互带和天窗交互带为重点，采用水文和水化学在线监测、现场测试、流量测量，结合水化学、浮游生物和微生物等的分析鉴定，剖析了交互带的水文、水化学特征和水生生物群落结构及其与水环境的关系。研究发现:岩溶洞穴交互带的水文功能有弱化趋势；泉口交互带的污染物降解能力明显，水化学功能尚能发挥作用；水生生物功能在退化，主要是由水文功能弱化导致的。水文功能弱化是岩溶洞穴交互带环境功能退化的重要原因。建议在岩溶地区的水文地质和环境地质工作中重视交互带，探索交互带的探测和监测技术，通过有效管理改善交互带的环境功能。 

Concept of karst cave hyporheic zone and its significance in water resource management

Groundwater recharge, runoff, and discharge modes in karst area dominated by conduit flow usually causes rapid and frequent interaction and transformation between groundwater and surface water, and therefore triggers the water environmental degradation. Single management of either groundwater or surface water cannot handle and resolve these problems. Take Wuming basin in South China as the case, the mechanism of karst groundwater interaction with other types of water and its environmental function was studied. The paper aims to understand the reason of karst water environment degeneration, and to provide recommendations for effective management of groundwater and surface river. Wuming basin is a typical peak forest area, with plenty of buried karst water. There are 148 groundwater systems in the basin, in which Lingshui spring is the largest and the most important one. Another four springs in the basin were selected too as the studied points. Online monitoring for water level and selected physicochemical parameters, in-situ measurements, and sampling analysis for water chemistry and plankton were used to study the characteristic of hyporheic zone in karst water system where are dominated by conduit flow. The concept of Hyporheic Zone (HZ) originated from hydrology and hydro-ecology is referenced and developed. Karst Cave Hyporheic Zone (CHZ) is defined as the site where conduit flow and other types of water interaction in South China. According to the water flow types and interaction styles, cave hyporheic zone is classified as spring outlet HZ, karst window HZ, sinkhole HZ, and karst conduit HZ. Focusing on spring outlet HZ and karst window HZ, the hydrology process, hydrochemistry characters, and aquatic organism community structure and its relationship with water environment are discussed. The results show the hydrology function of CHZ has a tendency of weakening due to the decrease of groundwater discharge. From the spring outlet to the CHZ, NO3-deceased by 6.5% to 90.9% and SO42- decreased by 2.1% to 18.1%. Degradation capacity of pollutant in spring outlet HZ is distinct, indicating that hydrochemistry function still plays a certain role in pollutant attenuation. Comparison of major community structure of aquatic organism in groundwater and HZ shows the biological function is degraded, mainly caused by weakening of hydrology function. Therefore, weakening of hydrology function is considered as the main reason for environmental function degradation in CHZ. It is suggested that CHZ should receive more attention in hydrogeology and environmental geology work in karst area. More techniques on exploration and monitoring for CHZ need to be discovered, and the environment function of CHZ should be improved through effective water management.