Land subsidence caused by groundwater exploitation in Suzhou City,China |
| |
| Authors: | Chongxi Chen Shunping Pei Jiu Jiao |
| |
| Institution: | (1) Institute of Environmental Geology, China University of Geosciences, Wuhan 430074, China,;(2) School of Earth and Space Sciences, Peking University, Beijing 100871, China,;(3) Department of Earth Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China, |
| |
| Abstract: | Suzhou City, located at the lower reaches of the Yangtze River in southeastern Jiangsu Province, is one of the few cities
in China which suffer from severe ground settlement. A research project was carried out to investigate this problem. Geological
and hydrogeological studies show that there is a multi-layered aquifer system with three distinct, soft mud layers of marine
and lagoonal origins. An examination of historical records of groundwater extraction, water levels, and ground settlement
shows that the ground subsidence is associated with the continuously increasing groundwater extraction in the deep, confined
aquifer. It is believed that the consolidation of the soft mud layers, especially the third layer which is thick and close
to the main pumped aquifer, contributes to the ground settlement. A three-dimensional finite difference numerical model representing
the multi-layered aquifer system was developed to study the ground settlement in response to groundwater extraction. By calibrating
the model with both the measured groundwater level and ground settlement, the aquifer parameters were estimated. The model
outputs fit reasonably well with the observed results, which indicates that the numerical model can reproduce the dynamic
processes of both groundwater flow and soil consolidation. The hydraulic conductivity of the third mud layer near the center
of the ground settlement has been reduced by over 30% in the last 14 years. The gradual deterioration in the hydraulic conductivity
of the mud may have significant adverse effect on the sustainable groundwater resource of the deep confined aquifer, since
the recharge from the shallow aquifers through the mud layer is the only source of water to the deep aquifer. An analysis
of the spatial distributions of groundwater drawdown and ground settlement shows that the area with maximum drawdown is not
necessarily the area with maximum ground settlement due to the occurrence of the soft mud layer. A simple reallocation in
pumping rates on the basis of the spatial distribution of the thick mud layer could significantly reduce the ground settlement.
Electronic Publication |
| |
| Keywords: | Groundwater Land subsidence Numerical simulation Finite difference Nonlinear consolidation |
| 本文献已被 SpringerLink 等数据库收录！ |
|
