Identification the Status and Dominant Factor of Eutrophication in the Newly Built Reservoir during the Impoundment Period

Abstract

In this paper, taking Laohutan reservoir in Huzhou city of Zhejiang province as an example, we systematically discussed the variation trends of trophic status in the early impoundment period of newly built reservoir and the dominant factor of eutrophication. It has been proved that the reservoir’s nutrition index in the early stage is on rise and the water body has a trend of eutrophication. According to actual situation, the outbreak of cyanobacteria and deterioration of water quality in September have showed the features of eutrophication. The dominant factors of eutrophication are total phosphorus, total nitrogen and dissolved oxygen, among which total phosphorus matters most to the trophic status. The results have laid great important foundation for people to explore evolution process of new reservoir ecosystem and the influences of hydraulic engineering construction to ecological environment, and they also provide reference for construction and management of other new reservoir.