The Kampereiland is an island located at the south eastern part of the IJsselmeer in the middle of the Netherlands. This island serves a purpose to lower water levels in the IJssel- and Vechtdelta during high water, by being inundated. This inundation is meant to result in lower water levels in the IJssel near Kampen. However, the flooding of the Kampereiland is a complex case. There are numerous stochastic variables that are used to determine the water levels, as well as breaching possibilities and a compartment structure which is present on the Kampereiland. All these aspects have influence on inundation of the island. In this thesis research, the flooding of the island is analysed, during multiple different types of high water scenarios, as well as with a variation of breaches or no breaching. This is all done while taking the compartment structure on
the Kampereiland into account.

To analyse how the Kampereiland floods, three main types of highwater scenarios have been analysed. These types are stormdominated scenarios, which are defined by high wind speeds and low discharges. The second type of high water is the discharge dominant scenario. The high water levels in these scenarios are reached by high discharges from the Vecht and the IJssel rivers, in combination with low wind speeds. Lastly, a number of extreme events have been analysed, to give a worst case perspective of the flooding of the Kampereiland. In these scenarios, high wind speeds coincide with high discharges from the two rivers, resulting in extreme water levels in the Ketelmeer, ZwarteMeer and in the Ganzendiep.

Each of the analysed scenarios have outside water levels exceeding the crest height of the flood defenses surrounding the Kampereiland. The scenarios have been analysed for multiple breaching cases. Three different breach locations have been determined. The locations have varying crest heights, type of flood defense (overflow resistant or non overflow resistant), type of high water (storm dominated or discharge dominated) and different hinterland compartments. Each scenarios has then been used to run the model to determine water levels in each compartment. This is done for situations without a breach, a single breach or two breaches at one location. The determination of the water levels is calculated by the use of spillway formulas.

The results show that the Kampereiland mainly floods from west to east. Storm dominated scenarios lead to high water levels in the Ketelmeer, leading to overflow from here. In scenarios up to 32 m/s wind speeds without breaches, the flooding is contained to the compartments to the west of the N50. The entire island floods once water levels increase due to wind speeds of 37 m/s and higher. Adding breaching into the storm dominated scenarios, the results are shifted. Now the evaluated scenarios with 32 m/s also lead to flooding
of the entire island. This case still leads to less high water levels on the Kampereiland than the scenarios of 37m/s without breaching, but every compartment is inundated.

The discharge dominated events are contained in the Willem Meyer- and Stikkenpolder. This is due to the presence of the old flood defense, which contains the flooding in cases with and without breaches.

Finally, the extreme events flood the majority of the Kampereiland, similarly to the stormdominated scenarios. The water levels that occur in the Zwarte Meer and Ganzendiep are higher during the extreme events. They also last longer than in the storm dominated scenarios. This results in a small inflow from the north
and southeast, while the western side of the Kampereiland rapidly fills up. Breaching during these extreme events leads to higher water levels when the breach occurs in the overflow resistant part of flood defense 225. The rising velocities in the west are also the highest in this case. Eastern compartments have higher rising velocities in case of breaching in flood defense 101 (along the northern boundary).

The water levels along the dike of Kampen are affected by the magnitude of the discharge on the IJssel and the water level set-up caused by the wind characteristics on the IJsselmeer. The Kampereiland has been assigned as a retention area to reduce the water levels near Kampen during a storm. This area should store excess water during a storm at the IJsselmeer of a magnitude corresponding to an annual exceedance probability of 1/500, to prevent this water from flowing in the direction of Kampen. The Kampereiland is protected by dike trajectory 225 and a part of this trajectory has been made resistant to the overflow of water. According to new insights, the crest of this dike section seems too high and the Kampereiland inundates less frequently. Furthermore, not sure is whether the water level at Kampen benefits from the inundation of the Kampereiland and what the consequences are for surrounding dikes. The Kamperzeedijk is one of these surrounding dikes and protects the city IJsselmuiden, along with the polder behind. The influence of the crest height of this overflow resistant part on the water levels at Kampen and at IJsselmuiden is investigated. The most important assumptions are that dikes do not breach and that the water level at Kampen remains constant after water flows into the Kampereiland. The influence on the water levels at Kampen and at the Kamperzeedijk is evaluated for multiple crest heights of the overflow resistant dike section. Eventually, these water levels are processed with a statistical model to compute multiple water level exceedance frequency lines for each location and for various chosen crest heights of trajectory 225. The results show that higher crest heights of trajectory 225 lead to increased maximum water levels at the Kamperzeedijk and to lower maximum water levels at Kampen, and vice versa. The water levels in front of the overflow resistant dike section remain unaffected. The return periods for overflow at Kampen and IJsselmuiden are derived by comparing the water level exceedance frequency lines to their individual crest heights. Concluded is that the inundation of the Kampereiland does not immediately lead to a load increase in front of the Kamperzeedijk. A delay is observed as a result of the storage capacity of the Kampereiland. As soon as water from the Kampereiland flows into the Ganzendiep, the loads rapidly increase. Furthermore, concluded is that the Kampereiland is capable of reducing the water levels at Kampen. Based on the results from this research, a crest height of 2.7m +NAP leads to equal return periods for overflow at trajectories 10-2 and 11-2. The reduction of the crest height by ten centimeters increases the return period for overflow at Kampen from 30,000 years to 45,000 years. At the Kamperzeedijk, the return period is reduced from 80,000 years to 45,000 years. In reality, these return periods are also affected by other failure mechanisms. A full dike assessment has to elaborate on this. Furthermore, trajectory 225 is assessed whether it meets its safety standard. It would be more legitimate to assess trajectory 225 by explicitly quantifying its consequences on trajectories 10-2 and 11-2