Impact of a water diversion project on the groundwater environment of Xiamen Island

摘要

The water in the Yuandang Lake of Xiamen Island has been seriously polluted by human activities, In order to alleviate water pollution, two schemes have been proposed to divert seawater, one east-to-west and the other west-to-east, both dividing Xiamen Island and posing great risks to the groundwater. From 2002, water has been diverted from west to east, but it has not significantly improved the lake-water quality; the east to west water diversion theme is under planning. In this study, a groundwater model was set up to further understand the local groundwater-seawater interaction, and to assess the risk of seawater intrusion. The finite-element method was adopted to analyse groundwater flow and seawater transport. We conclude that under annual average precipitation, seawater invasion will become stable one year after the project is completed. In low flow years, the seawater fringe will be close to the lakeside, resulting in seawater recharging the lake water through groundwater flow.