A tough day trying to get the video hooked up with the data acquisition system prior to starting our first proper wave tests…. The marsh, with 2m of water over the soil surface, looked remarkably peaceful through the underwater cameras – and while the first gentle waves were sent over the marsh section, we were watching from the control room via the video system… Plant stems began to sway gently, remarkably, even in such deep water depth and with very small and short waves. The data showed little sign of dissipation of wave energy yet – as expected and intended. A big sigh of relief. By gradually increasing wave energy, we are literally ‘inching’ our way towards the threshold between waves moving freely across the ‘rough’ bed and the bed causing them to lose energy (and thus to act as a natural sea defence).
Transfixed by the swaying motion of the tall stems of our marsh plants, we spot a leaf floating backwards and forwards past the underwater window and camera.. or, no! It has an eye! A fish in our ‘aquarium’!!
Clearly, the pipes that fill the tank with water from the Mittellandkanal, are big enough to allow fish to pass through…
Then, we spot a toad bobbing up and down in the gentle motion of the waves on the surface of the water and then diving down again, before we can even begin to think of a rescue mission… There should be plenty of food to catch under water and in the marsh, when the plants are given a day to breathe again, before we simulate some less comfortable wave conditions….