典型背斜槽谷区岩溶水资源空间分布格局与水质特征——以宜居河流域为例

Study of the spatial distribution pattern and water quality characteristics of karst water resources in a typical anticlinal trough valley:A case study of Yiju river basin

文章选取典型背斜槽谷区——宜居河流域作为研究对象,结合不同水文地质单元对流域岩溶泉进行出露特征及水质分析,研究结果表明:(1)二叠系、三叠系含水层的调查泉点水化学类型全部属于HCO_3-Ca型水,而寒武系、奥陶系含水层部分泉点属于HCO_3·SO_4-Ca型水,这可能与该地区的岩性及人类活动有关;流域内93.8%的岩溶泉点水质等级为优良和良好,可作为饮用水源;(2)流域内岩溶泉流量<10L·s^(-1)的岩溶泉数量占78%,平均流量仅为0.84L·s^(-1);流量≥10L·s^(-1)的岩溶大泉平均流量达76.56L·s^(-1);此外,发现不同岩性地层在岩溶泉发育的数量和流量上皆有差异,表现出岩溶泉发育的极不均一性;(3)在可溶岩与非可溶岩接触带、断裂构造带、陡崖处、地势较低的弱承压泄流区、深切河谷及峡谷两侧切割处5类地点易出露岩溶泉。

Karst springs are the mainly water sources of domestic water supply in karst mountainous areas,where anticlinal trough valley is an important part in the areas.To study the spatial distribution pattern and water quality characteristics in Chongqing karst anticline region,through the hydrogeology survey in the Yiju river basin,and combined with different hydrogeological units within the basin,of which is mainly composed of Permian and Triassic and Cambrian Ordovician aquifer,we analyzed the water quality and studied the distribution of the karst springs in different hydrogeological units.The results show that,（1）The pH value of karst spring in this basin is between 7.27 and 8.07,with the average value of 7.84 and most of them are neutral and weak alkaline.The total salinity of the samples falls in the range of 129-310 mg·L^（-1）.The Permian and Triassic aquifer water chemistry type spring survey all belong to HCO3-Ca type water,while the Cambrian and Ordovician aquifer part spring belongs to HCO3-SO4-Ca type water,which may be related to lithology and human activities in the area;93.8% karst spring water is of excellent and good quality,which can be used as drinking water resources.（2）The average flow rate of these karst spring is 0.84 L·s^（-1） and78% of them have a flow of less than 10 L·s^（-1）.The average flow of large karst springs with more than 10 L·s^（-1） is 76.56 L·s^（-1）.There are differences in quantity and flow of karst springs in different lithologic stratums,which shows the extreme nonuniformity of karst spring development.（3）In the basin with different hydrogeologic units,there are five preferential localities where the karst springs often occur,namely,the karst and non-karst contact zones,fault fractured zones,steep cliff,the low lying discharge areas with low confined,deep valleys and both sides of cutting canyons.