It has to be said, having the plants in the flume simply looks beautiful. And on the first day, when the water very slowly rose so as not to disturb the sediment surface while flooding the pallets, we could not stop admiring them and taking pictures of them until we almost got wet feet.
Once the flume was filled to the desired height, we switched on the instruments, started the waves and hoped for the best. The water was exceptionally clear for GWK standards, but still not clear enough to see in detail what was going on at the bed while the waves were running. The slow and careful draining process then meant even more waiting time until we could finally see the plants and surface again and started the first post-experimental measurements in high spirits.
One of the core sets of measurements that will be performed everyday are SET measurements. SET stands for sediment erosion table and it will give us detailed information on how the surface elevation of each pallet changes as a result of a wave run. The different plant heights and pallet configurations require slightly different setups in order not to bend the plants, but the method is always the same: A table or bar of a defined height is placed across the pallet which has a line of holes it is. We then feed pins through these holes until they just touch the sediment surface, fix them in position and read their height with graph paper. While an individual reading will not tell us a lot, comparison between the daily measurements will tell us exactly how the surface has changed. To ensure that we always measure in exactly the same locations, the FZK team had prepared tables whose feet precisely fit into holes in the metal bars that hold down the pallets. The fact that they thought about these holes when they designed the metal bars shows once more the team’s fantastic skills when it comes to designing experimental setups.