The Ludwig-Franzius-Institute takes part in subproject 4, in which large-scale physical model tests are going to be carried out. By that the development of the target vegetation will be investigated with and without wave load. This will enable to draw conclusions on the dike resistance and the necessary design recommendations. The hydro- and morphodynamic boundary conditions, as well as the most suitable target vegetation for the enhancement of the ecosystem value of the dike, are worked out by the project partners in subprojects 1 to 3. The key facts from the large-scale model experiments in subproject 4 will be considered in subprojects 5 and 6 and lead to the development of innovative monitoring techniques and recommendations for green dikes. At the same time, the Institute for Hydraulic Engineering and Water Resources Management of RWTH Aachen University is developing a sensor-based monitoring concept with smart geotextiles. These smart geotextiles are developed according to the specific hydraulic and geotechnical boundary conditions of green sea dikes and will be tested in the facilities of LuFI and IWW. The smart geotextiles will be able to identify stresses, deformations and soil moisture in order to get advanced knowledge about the resilience of a green sea dike.
At the moment the outdoor basin in Marienwerder is extensively upgraded for the large-scale physical model tests. Thereby a new outdoor wave basin with a length of 25 m, a width of 15 m and a maximum water depth of 1 m will be built. The wave maker will have two 3-5 m wide wave paddles, which can be controlled separately. For the study of vegetation development with and without wave loading, the wave basin is divided into two areas. Each of the areas contains a dike with the typical structure (sand core, clay layer, topsoil + grass cover and/or target vegetation) and a slope of 1: 6. The investigations should be carried out as long-term experiments over a vegetation period. To measure the hydraulic parameters, pressure measuring cells and wave runup gauges are installed. Also, the most important chemical and biological parameters might be monitored since they are able to influence the vegetation development. The following figure shows the probable experimental setup in the current planning stage of the new outdoor wave basin.