The Hangzhou-Jiaxing-Huzhou (Hang-Jia-Hu) Plain of Zhejiang Province, located between the Yangtze and Qiantang Rivers, has experienced severe land subsidence since the 1960s and has become one of the regions in China with most acute land subsidence problems. The historical records of groundwater extraction, hydraulic head, and land subsidence show that the land subsidence has resulted from the continuously excessive extraction of groundwater from deep confined aquifers. In this work, a coupled regional groundwater flow and land subsidence model is developed to simulate the evolution of land subsidence. The release of water from clay layers and associated land subsidence are simulated by the Subsidence and Aquifer-System Compaction (SUB) package for use with MODFLOW. Model calibration is carried out to achieve a reasonable agreement between the observed and simulated amounts of land subsidence in terms of both magnitude and spatial extent. Simulation results reproduce the centers of land subsidence and the cones of depression for groundwater heads reasonably well. The simulation model also indicates that the middle of the three confined aquifers and adjacent aquitards are the primary source of subsidence in the Hang-Jia-Hu Plain. The calibrated model is used to predict future land subsidence development under several groundwater exploitation scenarios and to provide a scientific basis for managing the beneficial use of groundwater resources in the Hang-Jia-Hu Plain while minimizing negative environmental impacts.
展开▼
