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Zongyu Chen, Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences (China)
Jixiang Qi, Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences (China)
Wen Wei, Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences (China)
Ying Wang, Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences (China)
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It is arguable whether we are "mining of a non-renewable groundwater resource" in the North China Plain. This paper demonstrated the groundwater renewability in the deep confined aquifer from the tracer data. Relatively modern ground waters occur in the piedmont plain. The contents of stable isotopes of samples in the piedmont plain close to the regional mean annual-weighted composition of meteoric waters. Tritium and 3H-3He age indicate young post-bomb recharge (<40yr) and therefore were renewable. And their depth-dependend distribution suggests local recharge from precipitation. Tritium-free below ground surface 150 m indicates an absence of modern post nuclear water recharge. Thus, the active groundwater recharge zone has a thickness of ∼150 m. In contrast, ground water in the central and littoral portions of the North China may date from10,000 yr B.P to 35,000 yr B.P by radiocarbon dating. These waters were isotopically lighter than younger groundwater by up to 2.2‰ for δ18O and 15‰ for δD. The temperatures estimated from noble gas suggested that this period was cooler by at least 4 C than present. This indicated that water recharge took place during the past glacial period. Groundwater velocities during last glacial maximum would have been greater because of the more distal position of the coastline. The tracers have suggested a slow natural replenishment rates to the central plain. These imply that groundwater in this area is limited and the aquifer has been overexploited. Groundwater in the highly-confined portions of quaternary aquifer systems could be considered as non-renewable resources, although the groundwater resources in deep aquifers are not strictly "non-renewable groundwater resources".
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