The environmental capacity features of nitrogen and phosphorus in Qingshuihai lake and storage capacity change in response to its relationship

This paper studied the change of nutrient aquatic environmental capacity of Qingshuihai lake before and after the water diversion project. The volume of the lake will be enlarged from 117.65 million cubic meters to 148.61 million cubic meters after the water diversion project is implemented. The research adopt the lake water environmental capacity model recommended by the national water environmental capacity approval technical documents authorized by state environmental protection administration, also the research calculated the aquatic environment capacity of major pollutants TP, TN, and the residual water environment capacity, as well as analyzed the response relationship among the aquatic environment capacity, reservoir inflow, and reservoir storage capacity in both cases. The results show that after the water diversion project is implemented, the TP water environmental capacity is to be enlarged from 34.97 tons per year to 46.55 tons per year. The TN water environmental capacity is to be enlarged from 1644.32 tons per year to 2124.56 tons per year. While the residual water environment capacity increases; The increase percentages of TP and TN are about 10 percent of the increase percentage of inflow, and almost the same increase percentage as the increase percentage of the volume. The research also implies that the environmental capacity changes of TP and TN are mainly affected by lake volume.