EVOLUTION OF QUATERNARY GROUNDWATER SYSTEM IN NORTH CHINA PLAIN

The Quaternary groundwater system in the North China Plain is formed m ainly through the terrestrial water flow action on the united geologic al and tectonic backgrounds. The analysis of groundwater dynamic field , simulation of groundwater geochemistry, and the C-14 dating and extr action of isotope information have provided more evidence for recogniz ing and assessing the evolution of groundwater circulation system and studying the past global changes. The exploitation and utilization of groundwater on a large scale and overexploitation have given rise to t he decline of regional groundwater level, change of flow field, decrea se of water resources and downward movement of saline water body. The water environment has entered a new evolution stage in which it is int ensely disturbed by the mankind's activities.