This paper is the result of geological survey engineering.
Objectives Groundwater resources is an important part of China's water resources, especially in arid and semi−arid areas. Thus, water prospecting and well drilling become a critical public welfare policy to solve the drinking water problem for humans and livestock. This study aims to summarize geophysical methods for water prospecting and propose possible pathways to improve the efficiency and success rate of finding water, thereby guiding the future exploration and evaluation of groundwater resources.
Methods Based on geophysical theories, this study systematically reviews basic principles and a series of case studies related to five geophysical methods for groundwater exploration under various hydrological and geological conditions: direct current electrical method, electromagnetic method, radiometric method, seismic wave method, and nuclear magnetic resonance method. Then, we compare the advantages and disadvantages of these geophysical methods for water exploration and figure out their applicable conditions. Finally, we propose effective methods for water detection under various geological settings.
Results This study proposes a basic approach to prospect groundwater using geophysical techniques. Moreover, we summarize effective methods for five typical geological environments: Karst, granite, sedimentary clastic rock, semi−consolidated red bed, and Quaternary loose layers. The summary will provide useful guides for the geological survey of groundwater resources across the nation.
Conclusions Geophysical methods for water prospecting should be carefully selected based on the hydrogeological characteristics of the exploration site. Based on our literature review, resistivity, induced polarization with multiple parameters, and seismic exploration are effective methods for groundwater exploration, while gravity, magnetic, and radiometric methods can serve as useful supplements. Integrated application of multiple geophysical methods can effectively improve the success rate of groundwater prospecting. Moreover, the lateral electrical resistivity method has large potentials in future evaluation of groundwater resource. However, we still call for continuous innovation in geophysical techniques for groundwater exploration given the needs in complex topographical and geological conditions such as mountainous areas, urban areas, and areas with thick coverage. In this regard, rapidly developing technologies like multi-parameter semi-airborne electromagnetic methods and ground holographic electromagnetic methods represent new directions for future water prospecting research.
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