Research of the water environmental capacity and the sewage control amount in Shaanxi reach of the Weihe River

According to the information of water quality, hydrology data and the discharge points´ distribution, this paper chooses COD for main control factor. Based on the 1-D steady-state water quality model, water environmental capacity for Weihe River in Shaanxi is calculated using two methods in dry year, normal-water year and wet year. Results indicate that middle reaches of the Weihe River is seriously polluted, and the annual quantity of pollutants reduction of COD is calculated according to the discharge amount in the relative year.