[Response of Algae to Nitrogen and Phosphorus Concentration and Quantity of Pumping Water in Pumped Storage Reservoir].

Taking a pumped storage reservoir located in southern China as the research object, the paper established a three-dimensional hydrodynamic and eutrophication model of the reservoir employing EFDC (environmental fluid dynamics code) model, calibrated and verified the model using long-term hydraulic and water quality data. Based on the model results, the effects of nitrogen and phosphorus concentrations on the algae growth were analyzed, and the response of algae to nitrogen and phosphorus concentration and quantity of pumping water was also calculated. The results showed that the nitrogen and phosphorus concentrations had little limit on algae growth rate in the reservoir. In the nutrients reduction scenarios, reducing phosphorus would gain greater algae biomass reduction than reducing nitrogen. When reducing 60 percent of nitrogen, the algae biomass did not decrease, while 12.4 percent of algae biomass reduction could be gained with the same reduction ratio of phosphorus. When the reduction ratio went to 90 percent, the algae biomass decreased by 17.9 percent and 35.1 percent for nitrogen and phosphorus reduction, respectively. In the pumping water quantity regulation scenarios, the algae biomass decreased with the increasing pumping water quantity when the pumping water quantity was greater than 20 percent of the current value; when it was less than 20 percent, the algae biomass increased with the increasing pumping water quantity. The algae biomass decreased by 25.7 percent when the pumping water quantity was doubled, and increased by 38.8 percent when it decreased to 20 percent. The study could play an important role in supporting eutrophication controlling in water source area.

[Simulation and evaluation on TIN and PO4(3-) -P reduction in Deep Bay, China].

Environmental Fluid Dynamics Code (EFDC), three-dimensional hydrodynamic and water quality models, are employed to simulate the transport of total inorganic nitrogen (TIN) and orthophosphate (PO4(3-) -P) in Deep Bay, China under different hydrologic conditions. It shows that, the computational results of TIN and PO4(3-) -P match very well with monthly-averaged field data in dry and wet seasons. The results of TIN and PO4(3-) -P reduction scenarios show that, it is necessary to reduce TIN concentration in Pearl River to Grade III to guarantee TIN in Deep Bay comply with the marine functional zonation requirement of the standard of Grade III. TIN and PO4(3-) -P concentrations in Deep Bay could comply with the marine functional zonation requirement if 95% TIN and PO4(3-) -P loading are reduced from the inflow when degradation ignores. When the degradation is considered, TIN could comply with the marine functional zonation requirement if 83% TIN loading are reduced from the inflow.