[Effects of intrusions from Three Gorges Reservoir on nutrient supply to Xiangxi Bay].

Frequent spring blooms have been observed in tributary bays of Three Gorges Reservoir (TGR) since its initial filling. In order to study Three Gorges Reservoir of nutrients by the River tributaries reverse effect, a well-designed field monitoring plan was conducted. The results show: there are significant intrusions from Three Gorges Reservoir to Xiangxi Bay to the surface, middle and bottom with three forms of intrusion respectively. The unique flow characteristics provide a hydrodynamic background of nutrient distributions of Xiangxi Bay. The average instantaneous fluxes of the input TN and TP of the intrusions from the confluence were 501.92 g x s(-1) and 48.17 g x s(-1), respectively; TN and TP loads originated from intrusions accounted for 43.4% and 21.5%, respectively to total amount in the whole year. The study shows that intrusion of the total nitrogen input, a large proportion of total phosphorus, and reducing the pollution loads of tributaries and upper reach basin of Three Gorges Reservoir is the fundamental way to eradicate algal blooms.