Socio-hydrologic perspectives of the co-evolution of humans and ground water in Cangzhou, North China Plain
This paper presents a historical analysis of the coupled human–groundwater system centered on the Cangzhou region in North China Plain, from the socio-hydrologic perspectives. The history of the co-evolution of the system is divided into five eras (i.e., natural, exploitation, degradation and restoration, drought triggered deterioration, and getting back to balance). The balance of the social productive force and natural variability dominate the evolution of the human–groundwater system in Cangzhou, which has been interpreted in terms of the Taiji-Tire model. The interaction between the groundwater utilization and the water table are regarded as the inner Taiji, with the over-exploitation as the major reason for the groundwater depletion, and the groundwater utilization pattern affected by the changing groundwater table. The external drivers of the co-evolution of the human-groundwater system in Cangzhou were specified as the social productive force and natural variability, which represents the outer Tire. An upgrading of the social productive force, which was triggered by the drought during 1997–2002, enhanced the ability to rebalance the human-groundwater system in Cangzhou, and increased the ability to mitigation climate variability. In the future, along with the launch of most strict water resource management strategy and the South-to-North Water Diversion Project, further restoration of groundwater environment could be anticipated. However, the occurrence of drought, as an external environment forcing, still remains an undetermined variable.