Sustainable Utilization Study Of Groundwater Resources In Circum-Bohai-Sea Region

Circum-Bohai-Sea region is one of three economic cycles in east of China, meantime it is one of the places where water resources is most shortage and geological environment is most vulnerable. For a long time overexploitation of groundwater, land subsidence and seawater intrusion and other geological disasters were induced and development tendency of geological disasters became serious. It is significant in supporting economic and social development of Circum-Bohai-Sea region to release contradiction of supply and requirement of water resources and strengthen guarantee of geological environment. The goal of the study is to implement effective measures in sustainable development of groundwater resources with some constraint condition of geological environment, and to serve for development layout of regional economy and societyl of Circum-Bohai-Sea region. In the study, according to latest survey data, author took Circum-Bohai-Sea as a whole, and made coastal zone as important study area, and regarded reducing geological disasters such as land subsidence and seawater intrusion as environmental constraint condition. Author studied structure of aquifer system of north, west and south, changes of hydrogeological and environment geological condition and groundwater resources and so on, and instituted reasonable development and utilization project of groundwater resources.From contrast analysis and study of dynamic change of flow field of groundwater system and hydrochemical field in recent tens years, the results showed flow fields of shallow groundwater and deep groundwater in most regions has obviously changed. Water quality of shallow groundwater had big changes and water quality of No.2 aquifer has been changed to a certainty, but water quality of No.3 aquifer and water quality of aquifers below the No.3 aquifer was basically stable.Study showed natural resources of groundwater were reducing in recent years influenced by climates and human engineering activities. At present, potential regions of groundwater mainly distribute in Liaohe plain, karst water distribution region of Taizi valley, north and southwest of Tianjin City and irrigation area of yellow river of north of Shandong province and so on.Groundwater overexploitation is main reason that induces land subsidence andseawater intrusion according to dynamic monitoring and analysis. In period of deep groundwater exploitation, there is power exponent relationship between land subsidence and production volume.By numerical simulation calculation and contrast study of hydrochemistry and water environment isotope, shallow groundwater can recharge deep groundwater by leakage,and deep groundwater has ability of refreshing in some degree. In addition, with mass exploitation of groundwater in No.2 and No.3 aquifer in recent thirty years, there is no obvious phenomenon that saltwater intrudes into under fresh water in a large scale. Movement of salt water bottom only arrives at the top of No.2 aquifer. So clay soil has function of filtrating salt. Author presented mechanics of shallow saltwater recharge deep fresh water.Study showed that most regions lacked of water resources in different degree except lower Liaohe plain, and main regions distribute in Hebei province, Tianjin city, and coastal region of Shandong province, Dalian and Huludao of Liaoning province.Countermeasures of groundwater resources sustainable development and utilization: optimization layout and layer of exploitation, increase development and utilization of shallow groundwater, moderation reducing deep groundwater exploitation; implementing multiple project of broadening water resources, such as inter-watershed water transfer, sea water desalting, exploration groundwater potential, construction groundwater reservoir and emergency stand-by well field and so on; enlarging development and utilization of salt water; utilization of underground space and rain-flood resources and implementing aquifer recovery and union dispatching of groundwater and surface water; development soil water resources survey and spread technique demonstration results of development and utilization of soil water; strengthening dynamic monitoring of geological environment; construction"digital Circum-Bohai-Sea"environmental geology information systems.