An analysis of the characteristics of water storage structure and the practice of groundwater exploration in the basalt area of Zhangbei County, Bashang, Hebei Province

Zhangbei County is located in the contiguous poverty-stricken area of Yanshan Mountain-Taihang Mountain.The geological conditions of the basalt area are complex, which makes it difficult to find groundwater, and hence water-shortage villages are commonly existent.Based on field survey, theoretical analysis and analysis of typical groundwater exploration examples, the authors investigated the water storage structures types in the basalt area and their water-enrichment factors and summarized three types of water storage structures in this area, i.e., monoclinic structure, fault structure, and large holes.The monoclinal water storage structure can be subdivided into platform type, plain buried type, volcanic cone type and valley type according to the basalt exposure conditions.In terms of the influencing factors of water-enrichment, the monoclinic water storage structure is mainly related to the connectivity of basalt holes and fissures as well as the lithology and structure of the clastic rocks in basalt.The fault structure type water storage structure is greatly affected by the mechanical properties of faults and the later activity of the faults.Tensional faults and the newly active faults have good water conductivity and water enrichment capacity.The water storage space of the large hole type water storage structure is huge and hence the water-enrichment is very good.The influence factors of water enrichment are mainly related to the size and connectivity of basalt caverns.The results play a significant role for improving the success rate of finding groundwater in basalt areas so as to solve the problem of drinking water safety for water shortage people.