LAND SUBSIDENCE PREDICTION IN BINHAI NEW AREA OF TIANJIN BASED ON SCENARIO ANALYSIS

Land subsidence is a kind of slow-onset geohazards and accumulated for over years.In terms of the main factors which potentially caused land subsidence,the numerical model of land subsidence was established.With three groundwater extraction scenarios,the computer program was compiled to predict the land subsidence in the process of dynamic changes of groundwater level.Maintaining the same condition of groundwater exploitation in 2007(Scenario 1),from 2007 to 2020,the maximum accumulative subsidence in Binhai New Area of Tianjin(TBNA) will be 640 mm and the average accumulative subsidence will be 268 mm.With 2% decreases in groundwater exploitation year by year(Scenario 2),the maximum accumulative subsidence will be 520mm and the average accumulative subsidence will be 177mm.With the water from South-to-North Water Transfer Project replacing groundwater exploitation completely(Scenario 3),the maximum accumulative subsidence will be 150 mm and the average accumulative subsidence will be 95 mm.