The approx. 84 ha large Hooksmeer was created in the area of the existing tideway at the beginning of 1970s as a compensation area when the industrialized Voslapper Groden was embanked. Since then the former sluice port forms the western end of the artificial brackish water area which is separated by the sluice from the inner Jade to the east and thus can be characterised as an almost stagnant water. Later on, an extensive touristic infrastructure was built at and in the lake Hooksmeer which essentially contributed to a sustained increase in tourist attraction.
Since the end of the 1980s, odour nuisances, often together with large-scale fish mortality, increasingly occurred at the old harbour in the western part of the water. Since the available knowledge about the reasons for these incidents was inadequate, even extensive technical and high-cost action did not lead to the expected success.
IMP started systematic surveys to determine the reasons for these recurring shortage conditions in Hooksmeer. The analysis showed that a stratified water body with a bottom layer with nearly no oxygen in the deeper portions formed during the warm months of the year. South-westerly winds which are frequent in the area blow along the dominant longitudinal axis of Hooksmeer with the result that due to hydrostatic compensation currents this oxygen-free water layer reaches up to the surface at the funnel-shaped area of the old harbour and its access area.