There has been great shortage of water resources in Tianjin City,and the excessive groundwater extraction in recent years resulted in serious land subsidence.Until 2009,the area of land subsidence coverage was approximately 8900 square kilometers in Tianjin City and the largest cumulative land subsidence was more than 3 meters.The Middle Route of the South-to-North Water Diversion Project in Tianjin City will be completed in 2014,and the water supply,storage,and transfer projects in Tianjin City are all loc...