Characteristics change of nitrogen and phosphorus nutrients and water strategies in Gaozhou Reservoir

We analyzed the changing trend of nitrogen and phosphorus nutrients during 2012 to 2013 in Gaozhou Reservoir, discussed the variations characteristics of the concentration of nitrogen and phosphorus, and present the strategies for the water quality management based on the reservoir management and hydrodynamics. The concentration of total nitrogen and total phosphorus was in the high level during the abound water period, illustrating a large amount of nitrogen and phosphorus nutrients brought by the agricultural non-point source pollution into the reservoir. The entrance branch rivers were the main source of the nitrogen and phosphorus nutrients of the reservoir. The experiment of the ratio of nitrogen to phosphorus showed that parts of water in Gaozhou Reservoir appeared alternately in the stage of restriction of nitrogen and phosphorus, and the ratio of nitrogen to phosphorus had a positive relation with total phosphorus, reflecting the restriction stage of phosphorus in the water of the reservoir. Because of the concentration of population distribution on the rain collection area of upper portion of the reservoir, the nutrients were mainly from the living sewage and the input of agricultural non-point source pollution. Proper measures to deal with the living sewage and control the industrial pollution can decrease the input of nutrients in reservoir. In addition, changing the way of discharge of Gaozhou Reservoir can inhibit the growth of phytoplankton and algae, and reduce the possibility of reservoir eutrophication.