Analysis On Water Pollution Loading Of The Three Gorges Reservoir In Chongqing City

The Three Gorges Project(TGP) on the Yangtze River is the world-famous largest hydroelectric project. It will possess comprehensive utilization benefits for flood control, power generation and navigation improvement. But the construction of TGP will produce widespread and profound impact on ecology and environment.Through a series of analysises, this paper first shows that water in some area of the Three Gorges Reservoir(TGR) will eutrophicate in special time after sluicing. And then, the paper estimates the loading at present(the year of 2002) and in the furure(the year of 2010 and 2010) of nutrimental pollutant discharged into waterbody from each main pollution source of TGR in Chongqing City, such as the wastewater of industry and city life, rural discharges, surface runoff of farmland, rainfall runoff in the town, shipping and discharges of the soil flooded after sluicing. Futhermore, the paper sums up the total pollution loading of the whole reservoir in Chongqing City, and analyses the distributing of pollution source and region. Finally, the paper comes to the following conclusions:Firstly, in 2002, the total pollution loading of CODCr into waterbody of TGR in Chongqing City is 473 thousand tons, the total of NHs-N is 72.6 thousand tons, and the tatal of TP is 32.4 thousand tons. In 2010, the total of CODCr is 441.4 thousand tons, reduced by 6.69 percent, compared to the yearof 2002, the total of NHs-N is 72.4 thouand tons, reduced by 0.18 percent, compared to the yearof 2002, and the total of TP is 32.4 thousand tons, equal to 2002. In 2020, the total of CODCr is 442 thousand tons, reduced by 6.55 percent, compared to the yearof 2002, the total of NH3-N is 71 thouand tons, reduced by 2.16 percent, compared to the yearof 2002, and the total of TP is 30.9 thousand tons, reduced by 4.63 percent, compared to the yearof 2002. The loading of pollutant produced by each county of TGR in Chongqing City will largely increase, along with the development of economy and society. However, the quantum of pollutant discharged into waterbody of TGR will not increase but decrease.Secondly, surface runoff of farmland, wastewater discharge of city life and rural discharges are the key pollution sources of TGR in Chongqing City. In 2002, 92.02 percent of the total CODCr loading, 98.49 percent of the total NH3-N loading and 99.59 percent of the total TP loading are from them. In 2010, 89.78 percent of the total CODCr loading, 98.11 percent of the total NH3-N loading and 99.43 percent of the total TPloading are from them. In 2020, 84.27 percent of the total CODcr loading, 96.73 percent of the total NHs-N loading and 99.27 percent of the total TP loading are from them. Surface runoff of farmland is the most important pollution source.Thirdly, the Chongqing City zone, Wanzhou City, Puling City and Jiangjin County are the key regions of pollutant discharging in TGR of Chongqing City. In 2002, 47.70 percent of the total CODcr loading, 41.59 percent of the total NHa-N loading and 37.84 percent of the total TP loading are from the four counties. In 2010, 42.68 percent of the total CODcr loading, 40.84 percent of the total NH3-N loading and 37.12 percent of the total TP loading are from them. In 2020, 42.16 percent of the total CODcr loading, 41.96 percent of the total NHa-N loading and 37.20 percent of the total TP loading are from them.