Study On The Relationship Between Sand And Contaminant Of Chongqing Urban Section Of Three Gorges Project After Impoundment

The environment problems of the Three Gorges Reservior have being cared since it was started. With the construction of the Three Gorges Project, the Three Gorges Reservior will be more than600kilometers in length,1084square kilometers in area, and will be able to hold about44.57billion cubic meters of water. The project will be the foremost tactic water resource in China. On October,2010, the Three Gorges project reached the highest water level175meters for the first time. As the water level elevated, velocity slowed down, the environment of water body in the Reservoir tail and the existing form and the space-time distributing rule of contamination would change in TGR.Whereas the content of sand in TGR is high, the effect of sand to the environment of water body in TGR is not allowed to be neglected. Chongqing urban section of the Yangtze River lies on the upper river in the fluctuating backwater region of TGR. The research of the content of contaminants and their distribution rules based on sand and sediment in the water body can provide a scientific basis for the regional water environment change and its countermeasures.In this study, the characteristic of suspend sand and sediment are considered to discuss the regular pattern of influence which the suspend sand and sediment have on the contaminants in Chongqing region of TGR.At first, the water quality has been evaluated based on monitoring data of main sections in Chongqing region of TGR. Afterwards, the relationship between suspend sand and contaminants has been analyzed, and the contaminants have been evaluated by field sampling and simulating experiments. Moreover, the relationship between sediment and contaminants has been studied. Finally, the formula of contaminants and suspend sand and sediment has been fitted combined with the measured data.The results turn out that:The water quality in Jialing River is better than that of Yangtze River, and there appears IVlevel water which can’t be taken as drinking water source in Chongqing urban city, which means the water quality has been worsen; The content of suspend sand in the water body has great influence on the content of contaminants; Different water sampling treatments have direct imfluence on the measured value of contaminants in water body, therefore, it’s necessary to point out the treatment of water sampling or else it will lack contrast; The pollution of Cd in Chongqing urban section of the Yangtze River is serious; The content of contaminants in sediments increases along with the drop of the particle size of sediments, especially when the particle size is smaller than0.08mm, whose range is remarkable.