Numerical evaluation of land subsidence induced by groundwater pumping in Shanghai

TLDR

The study establishes a numerical model to predict future land subsidence in Shanghai caused by groundwater pumping. The model couples 3‑D groundwater flow with 1‑D soil deformation, incorporates Shanghai’s multi‑aquifer hydrogeology, and simulates changes in soil compressibility and hydraulic conductivity during consolidation. The model shows that land subsidence correlates with groundwater withdrawal volume and level, matches measured data closely, and predicts future subsidence trends over the next 30 years based on projected withdrawal, pumping depth, and region.

Abstract

To predict the future behavior of land subsidence in Shanghai due to pumping of groundwater, a numerical model is established. In the proposed model, groundwater flow in three-dimensional conditions and soil deformation in one-dimensional conditions are calculated. The model takes into account the multi-aquifer-aquitard hydrogeological condition of the soft deposit of Shanghai. The variation of the coefficient of compressibility and coefficient of hydraulic conductivity of the soils with the consolidation process are simulated. Relationships among land subsidence, groundwater withdrawal volume, and groundwater level are analyzed. Comparison between the measured value and calculated value shows that the model simulates the measured value fairly well. The future of land subsidence behavior due to groundwater withdrawal is predicted and discussed via consideration of the variation of the following parameters in the future 30 years: net withdrawn volume of groundwater, pumping layer, and pumping region.