Abstract: The ecological environment of Shennong Stream has been greatly changed since the impoundment of the Three Gorges Reservoir. The vertical stratification and seasonal variation of water temperature (WT), dissolved oxygen (DO), and chlorophyll-a (chl-a) were measured by field monitoring in Shennong Stream in 2016. The results showed that the surface water temperature varied from 10.6 ℃ to 32.4 ℃. The water temperature structure was greatly affected by the hydrodynamic conditions. The vertical water temperature structure was “stepped” in spring under the reverse current density from the surface of mainstream, “doublemixed” distribution in summer under the reverse current density from the middle of mainstream, and was changed into “half a U-shape” in autumn and winter under the reverse current density from the bottom of mainstream. The vertical distribution of DO and chl-a concentration was affected by water temperature stratification. The DO was significantly stratified in spring and summer. The vertical distribution of DO was affected by chl-a concentration in spring and by water temperature in summer. Our results provide reference for analyzing the change of habitat conditions of Shennong Stream and for water environment management and water resources utilization in the Three Gorges Reservoir area.

Key words: throughfall, stemflow, dissolved organic matter, concentration, quality.