IMIS - Marine Research Groups

Within the Upper Zeeschelde navigability project (project number 13_131), historical high and low water levels (from 1930 onwards) were digitised for five tide gauges in the Upper Zeeschelde. This analysis is an extension of an earlier report for the Lower Zeeschelde (00-035 - V&T DR6). However, within this last study, use was made of values from the 10-year overviews and therefore only a limited number of parameters could be analysed (e.g. the duration of the fall and rise was only available in the last few decades). However, to gain further insight into the historical evolution of the tide in the entire Scheldt estuary, it is necessary to further expand this digitisation so that all parameters can be analysed. The first phase of the requested project will focus on the high and low tide levels for five ‘mother’ stations within the main tide stations that will be digitised from 1880 onwards. In the second phase, the remaining main tide stations will be digitised, not only those in the Zeeschelde but also those in the tributaries. After the digitisation exercise, the characteristic tidal parameters (high and low water levels, rise duration, fall duration, time delay relative to Vlissingen/Antwerp, etc.) will be derived and the extent to which these parameters have changed historically will be examined. The expected change in tidal parameters over time is then analysed in relation to a number of explanatory parameters. We expect morphological changes in the estuary to have a significant influence on this. This analysis should improve our understanding of how the system functions and enable us to better advise managers on the challenges of the future, including rising sea levels and the risk of regime shift.