Analysis on factors inducing algal bloom in reservoir based on basin eutrophication model

The distributed hydrologic model SWAT was integrated with the vertical 2-D eutrophication model to establish an eutrophication model for narrow and long reservoirs.The model was applied to analyze the main factors causing the algal bloom in the Fuchuanjiang Reservoir.The result shows that the hydrological factor is the most sensitive inducing the occurrence of algal bloom in 2004.The prevention measure by means of ecological water diversion project is suggested and the feasibility of this project under the environmental condition of 2006 is analyzed.It is found that a functional relationship between runoff and amount of algae exists,when the runoff of the reservoir higher than 600m3/s,the occurrence of algal bloom can be effectively prevented.Furthermore,an experiment in laboratory for studying the relationship between the growing of algae and period of water changing indicates that the growth of Microcystis can be inhibited when the period of water changing less than 3d.This result is approximately the same as the calculation result based on the eutrophication model.