Impact of the Three Gorges Project's Operation on Low Water Level in Changsha Reach

In view of the seriously drought and the condition that the water level in Changsha reach continuously break the historical lowest records in recent years, the variation law of low water level in Changsha reach and the impact of the Three Gorges Projects operation on low water level were studied. The results show that the water level in the same discharge and the monthly averaged water level and the lowest water level all decrease year by year, and the appearance time of the lowest water level in recent years is earlier. The lowest water level in Changsha reach isnt much connected with the variation of water level in Dongting lake, but connected with the riverbed undercutting caused by the operation of hydro-junction and the excavation of sand. The appearance time advance of the lowest water level is connected with the Three Gorges Projects operation.