In view of the water environment pollution on a basin scale, the risk sources and the influential factors are identificated. It is found that the main factors include the natural environment, the economy and the society, and the main pollution sources are those of nonpoint and point. According to the watershed features, the classification of the risk degrees, and the methods of risk assessment are discussed for the basin water environment from three aspects:The eutrophication, the organic matter and the heavy metals. Basin water environmental risk control strategies are proposed to reduce the pollution risk of the river basin water environment or reduce the pollution damage. It is pointed out that the water pollution control in a basin scale should be strengthened. In addition, a prevention and control system for the basin water environment risk needs to be established.

basin scale  /  water environment pollution  /  risk assessment