The sea level has stopped rising! (in the flume...)

So our sea level rise experiments have finished. This morning we finished testing the highest water level of 4.9m on our dynamic revetment and have now moved on to testing storm conditions. As described in the previous blog post, the revetment responded interestingly to sea level rise forcing - the revetment retained the majority of its pebbles and the toe remained in the same cross-shore position, but the revetment face lowered considerably due to underlying sand being lost. This lowering, with a fixed toe position, resulted in a steepening of the revetment and a thinning of the revetment face thickness. During SLR step 3 (water level 4.8m) and step 4 (water level 4.9m) we did observe pebbles beginning to 'roll-over' and build up the crest of the revetment - as we'd hoped would happen with this 'dynamic revetment'. Throughout the final test at water level 4.9m, underlying sand loss also appeared to be reducing, and the revetment was becoming relatively stable in its position and steepness. We did wonder whether or not having an initially thicker revetment face may have mitigated some of the underlying sand loss and the resulting lowering of the revetment. Fortunately we will get a chance to test this next week! We have time enough to drain the flume, add more pebbles to the revetment, and then re-run some waves.

Figure 1 - The revetment after the sea level rise experiments.

Figure 2 - Here I am looking professional in the flume.

For now, we have begun testing 'storm waves'. The water level has been fixed at 4.9m (the highest applied SLR scenario), and Hs has increased by 10cm to 0.9m (Tp = 6s). We are observing very high rates of overtopping in these tests and pebbles are moving around quite a lot on the revetment but we will have to wait until we collect more profile data to determine if the revetment is responding 'dynamically' to these storm conditions. 

Figure 3 - Overtopping waves during storm conditions.