Estuaries are places where the flood risk is coming from both land and sea direction, which can lead to hazardous compound flooding. Modelling-based studies are dealing with prediction and mitigation of flood risk by simulating the behavior of flood events and by quantifying relevant parameters. In this study LISFLOOD-FP hydrodynamical model is used to evaluate the effect of different management strategies in estuaries, following the main hypothesis which states that changes in estuary shape (flood defense system) are having larger impact on flood risk than changes in flood drivers or sources, such as climate change. The second part of the study is focused on modelling different (design) storm events, regarding different relative timing of flood peaks, different storm durations and magnitudes. In the final part of the study the results from these two groups of analyses are discussed. It is
shown that changing the management strategy is having a larger control on flooding in estuaries, but not necessarily leading to higher water levels. The special focus was placed on the importance of nature-based elements of flood defense systems, like floodplains and salt marshes. It is confirmed that these elements can play an important role in mitigating the flood risk.