The pollution characteristics of Liangtan River in Three Gorges Reservoir region

Liangtan River is a typical and heavily polluted branch river of the Three Gorges Reservoir. A survey and analysis of the pollution condition of the river can provide basic data and over planning consideration for basin pollution prevention and environmental rehabilitation, based on which a monitoring survey was carried out and analyzed on water quality of Liangtan River. The analysis found out the spatial distribution of the river basin and the pollution load contribution rate of agricultural sources, sewage and industrial wastewater, Urban non-point source and river endogenesis under certain weather conditions of the water quality and flow monitoring. The results showed that most monitoring sections of Liangtan River were worse than V national water quality standard during rain period and non-rain period. The contribution rates of CODcr in east branch during rain period are: Urban non-point source, river endogenesis>; agricultural sources>; sewage of town and industrial wastewater while in the west branch are: agricultural sources>; sewage of town and industrial wastewater>; Urban non-point sources, river endogenesis. It seems that the NH4⁺-N and TP loads in upstream mainly come from sewage and industrial wastewater while in downstream mainly come from Urban non-point sources and river endogenesis in both branches. The contribution rates of TN load in east and west branch are: agricultural sources>; Urban non-point sources, river endogenesis>;sewage of town and industrial wastewater.