Flood Routing In Tidal Reach From Datong To Yangtze Estuary

China has been frequently hit by big floods and suffered from flood disasters. The critical issue shows that about 8% of the land area located in the middle and down stream of the seven major rivers are prone to floods, where is inhabited 50% of total population and contributes over 2/3 of total agricultural and industrial product value. So, it is active demand to study flood routing in down streams which usually affected by tide. This thesis developed some arguments of former studys and focoused on the property of flood routing in lower reaches of Yangtze river, from Datong to the estuary.According to the simulation, the tidal effect is different along the reaches. It is strong in the estuary area and dedused tracing to upper reaches, the tidal is very limited at Nanjing staion and nearly none at Tongling staion.The flood peak declines with routing down and flood discharge is waved by tide. In the flood tide stage, the discharge is lower and getting higher during ebb tide stage.The flood tide stage is shorting from down to up as the ebb stage getting longer.