Spatiotemporal Evolution And Simulation Of Salinity In Groundwater In Cangzhou

Groundwater in Cangzhou area is over-exploited for decades for both shallow and deep aquifers, which disturbed and caused the downward movement of the interface between freshwater and saline water. It threatened the safety of groundwater usage in deep aquifer. Through collecting data from literature and field investigation, the author obtained the temporal and spatial distribution of the groundwater total dissolved solids (TDS) and established the flow model in Cangzhou area. The transport characteristics of deep and shallow groundwater salinity were predicted, and the impact of various factors on the extent of salinity were analyzed. The results is as follows:(1) The content of TDS in both deep and shallow groundwater increased from 1980s to 2010s with different increasements. The high values of TDS decreased from coastal to the middle area then to western area of Cangzhou for shallow and deep groundwater. The reduction of net water supplement to groundwater and seawater intrusion were main factors leading to the increasement of TDS.(2) Numerical simulation of groundwater flow shows that the diffusion range of salinity increases along with the time of groundwater extraction time, and the content of salinity decreases with the increase of groundwater burial depth. Deep pumping most influences and promotes vertical migration of salinity; the increase of dispersion also can promote the vertical migration of salinity; the increase of shallow pumping hindered the vertical migration of salinity to some extent; the hydraulic conductivity of skylight can promote the vertical migration of salinity when increases in some range.