Harmful cyanobacteria blooms adversely affect water quality of fresh water systems which is particularly problematic in drinking water reservoirs. The poster will show how ecological modeling can be used to predict the succession of major phytoplankton taxa in Lake Wivenhoe (QLD). A two year data set of phytoplankton species in this reservoir is used to calibrate the DYRESM-CAEDYM model and capture the major environmental drivers such as shifts in flow and nutrient loading. Model-based prediction of phytoplankton succession due to environmental drivers and different anthropogenic stressors can potentially be used in supporting lake management.