Multitemporal TM image analysis to assess the spatial and temporal dispersion of floating macrophytes in Brazilian hydroelectric reservoirs

The focus on macrophyte community has increased due to their implications either on the electricity generation or on greenhouse gas production and emission. A TM/Landsat5 time series was used to assess the spatial-temporal variability of the area covered by floating macrophytes in Tucuruí dam, Pará State. The map produced by Boolean operation among classified historical images suggests that tributaries have suitable conditions for the retention of macrophyte stands. This fact may be assigned to the constant nutrient availability, to the lower hydrodynamic processes, and to the dead tree trunk effect producing a windless environment and a substrate to macrophytes in the tributaries.