Dynamic Revetment - Response to Storms!

We have now finished testing the response of our dynamic revetment to storm conditions (using various combinations of higher wave heights and longer periods). During these tests significant overtopping was observed and the revetment changed a lot. The revetment appeared to try and form a new flatter equilibrium shape in response to storm conditions. Over the course of the tests we observed the front slope of the revetment vary from the initial 1:4 to a flatter 1:6. This change was primarily driven by large overtopping events that pulled the revetment crest down the front slope. Our observations indicated that the equilibrium shape of the revetment was primarily driven by the wave period. While large overtopping events did flatten the revetment, they also carried pebbles landward and we saw a notable amount of deposition of pebbles landward of the revetment.

Figure 1 - A large overtopping event causing significant movement of pebbles.

Figure 2 - The flattened revetment after being exposed to storm conditions.

Following the storm tests that effectively flattened the revetment, we reverted to initial wave conditions for a few hours to see what would happen. Much to our delight, after only 2 hours of normal wave conditions, the revetment crest began to rebuild and the front slope reverted back to more-or-less a 1:4 slope. A dynamic revetment indeed!

Today, the flume paddle required maintenance. The three of us remaining at the flume (Paul, Gwyn, Tom) took the opportunity to RFID the tagged pebbles in the revetment, and then add an extra 4m^3 of pebbles to the revetment face so that we could test our hypothesis of whether or not a thicker revetment face could mitigate underlying sand loss (and associated revetment lowering) or change any of the behaviour observed in the tests performed to date. Tomorrow will be our last day of testing in the flume, where we plan to hit our new thicker revetment with normal and storm wave conditions!

Figure 3 - The new revetment with added thickness on the front slope!

Figure 4 - Paul taking a nap on the beach after a long day.