| 要約: | Basic hydrogeological surveys mainly targeted at the evaluation of groundwater resources were launched after the founding of the People's Republic of China, and have been advancing with the change of social needs and the development of relevant disciplines at home and abroad. Regional hydrogeological surveys nationwide mainly include the 1∶200,000 surveys from 1974 to 1982, mainly estimating the average groundwater recharge and runoff by the precipitation infiltration coefficient method and the runoff modulus method, and the utilization rates of the results are still very high. From 1999 to 2002, the 1∶250,000 groundwater resources survey and ecological environment geological survey were completed. Based on the 1∶200,000 hydrogeological survey, the latter was carried out by monographic study, compilation and measurement. In this kind of survey, changes of groundwater resources and problems of geologic environment in the past 20 years were initially identified. Meanwhile, taking watershed as a unit, the average groundwater recharge was estimated by precipitation infiltration coefficient method and runoff modulus method. The storage capacity of water-rich blocks, large spring and underground river systems were estimated by volume method and spring flow attenuation coefficient method. Exploitable amounts were estimated by observation and statistical analysis of spring and underground river flow and the section method of basin (valley) area. The potential of groundwater resources was estimated for the first time. Since 2003, the Institute of Karst Geology of China Geological Survey has continuously organized and implemented 1∶50,000 surveys on hydrogeological geologic environment in the southern karst areas, with a survey area of more than 30×104 km2. Field surveys were carried out according to the topographic map of 1∶50,000, and the groundwater resources were evaluated according to different basins. The recharge was calculated mainly by the precipitation infiltration coefficient method; the storage capacities of water-rich blocks, big springs and underground rivers were calculated by the volume method and the spring flow attenuation coefficient method; exploitable amounts of springs and underground rivers were calculated by the flow observation and statistical analysis; exploitable amounts of the water-rich blocks were calculated by theoretical and empirical formulas. The potential of groundwater resources was estimated according to the degree of exploitation and utilization of groundwater resources. The evaluation results of groundwater resources are mainly the level-D exploitable amount, that is, the inferred potential resources. This study primarily aims at countermeasures of the problems discussed here and the corresponding grades of groundwater resources. By reviewing a large number of data and materials about inspection records and comments of 1∶50,000 hydrogeological survey projects in karst areas of South China, referring to relevant literature and comparing with current norms and management requirements, this study analyzes and summarizes the existing problems and deficiencies of some investigation projects. These problems mainly include poor research work and results, insufficient connection between theoretical research and practice, insufficient Quaternary geological surveys, poor drilling control and low successful rates of water exploration, and incomplete evaluation of water resources. In addition, this study explores the subjective and objective reasons for these problems, for example, complexity of the karst hydrogeological conditions in South China, less accuracy of geophysical water exploration, relatively low quality of project results and the assessment index of the research, and project members' insufficient professional knowledge and experience. Finally, this study proposes some suggestions to improve hydrogeological survey, such as making effective organization and implementation plans, promoting comprehensive research in a standardized, continuous and efficient way, strengthening research on the selection of research topics, implementing effective monographic study, improving the accuracy of Quaternary geological mapping, strengthening the identification analysis, improving the proof of hole location and the exploration efficiency, strengthening the analysis of resources and environment, and improving the evaluation content.
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