香溪河岩溶流域水文地球化学特征分析

湖北宜昌香溪河流域碳酸盐岩分布广泛,岩溶地下水是当地居民的重要供水来源,研究地下水水化学组成的形成及内在规律,对当地地下水合理开发利用具有重要意义。以岩溶水为重点研究对象,并结合与岩溶水联系密切的降水、相邻非碳酸盐岩地下水、地表水,分析了香溪河流域水文地球化学特征。结果表明:研究区降水属于矿化度和硬度均低的弱酸性水,具有较强的侵蚀作用;研究区地表水化学组成是地层岩性比例的反映,干流受农业影响大而受工业活动影响小;受山区地形控制,研究区地下水矿化度较低,矿化度主要集中在150~300mg/L,并受地层岩性影响,碳酸盐岩裂隙水、岩浆岩裂隙水与碎屑岩裂隙水化学组成有所差异,总体来说水化学类型以HCO3-Ca型、HCO3-Ca+Mg型和HCO3-Mg+Ca型为主,同时受降水和温度影响,不同季节矿物溶解特点不一,地下水水质受农业药物影响程度较低。

Analysis of Hydrogeochemical Characteristics of Karst Basin in Xiangxi River

Carbonate rock is widely distributed in Xiangxi River basin of Yichang,Western Hubei.The karst groundwater is an extremely important water source for the local residents.To research the hydrochemical composi-tion and internal rules of groundwater has great significance to the rational development and utilization of the groundwater.Focused on the karst groundwater,this paper analyzes the hydrogeochemical characteristics of karst basin in Xiangxi River in combination with precipitation,groundwater in non-carbonaceous rock and surface water, which are closely linked to karst groundwater.The results show that the precipitation of the study area is weak acid water with low salinity and hardness and of strong erosion.The chemical composition of surface water reflects the lithological distribution,as the main stream is more influenced by agricultural activities than industrial activities. Under the control of the steep terrain,total dissolved solids of the groundwater is low,mainly ranging from 150 to 300 mg/L.Under the control of lithology,there is a sensible difference in hydrochemical composition between water samples collected in carbonate rock,magmatic rock and clastic rock and the Shukalief classification of which are mainly HCO3-Ca type,HCO3-Ca+Mg type and HCO3-Mg+Ca type.Influenced by the precipitation and tempera-ture,seasonal characteristics of the mineral solubility vary.Agricultural activities have little effect on the quality of groundwater.