A study of the influence of land subsidence on hydraulic parameters and water supply capacity

Land subsidence is mainly caused by the exploitation of groundwater in deep-seated aquifers, which is mainly composed of the compressed water release from the aquitards. At the same time, the reduction in void ratio caused by the compression of the aquitards will further reduce the storage coefficient and the coefficient of permeability, which will affect the amount of non-elastic water release and leakage recharge of the aquitard. The nonlinear variation in hydrogeological parameters and the feedback effect on the confined aquifer systems during land subsidence have also become frontier issues in hydrogeology. In order to make a quantitative and qualitative exploration of the relationship between the amount of groundwater extraction, amount of sedimentation, changes in geological parameters and changes in water supply capacity, this paper constructs a 1-D nonlinear settlement model of the change in storage coefficient and coefficient of permeability based on the change in groundwater levels and hydrogeological parameters of the deep confined aquifer in the Changzhou area. The simulation results show that the storage coefficient can be reduced by up to 77% with the decrease in hydraulic head of the confined aquifer, and the water supply capacity and water storage capacity of the aquifer system will decrease by 50% or more with the compression deformation. The research results are of important reference significance for understanding the relationship between hydrogeological parameters and stress changes and scientifically evaluating the groundwater storage capacity of confined aquifers.