This thesis reports on a study of the water quality in the Markermeer, focusing on the relationships between sediment transport, the light field and the growth of Oscillatoria agardhii . The study comprises two aspects: an extensive data collection program with the data analysis, and the development, calibration and application of a set of dynamic models, in order to assess the effect of management measures on these water quality aspects.The data collection program contained weekly and hourly monitoring of water quality variables. Characteristics of the sediment and characteristics of the light field were measured in fall velocity experiments with various sediment samples. Experiments were conducted with light and dark bottles and with a large perspex cylinder filled with Oscillatoria agardhii and placed in the lake. These experiments produced information on the growth characteristics of Oscillatoria agardhii in the Markermeer and on different kinds of adaptation of growth parameters to the light conditions.The model that has been developed to simulate the effect of management measures on the water quality of the Markermeer focusing on the effect of Oscillatoria agardhii , combines a sediment transport model (STRESS-2d), a light attenuation routine (CLEAR) and a growth model for Oscillatoria agardhii (ALGA). With the integrated model the effect of two management scenarios has been evaluated: the construction of the Markerwaard and increased flushing with water from the IJsselmeer.