Large-scale morphodynamic experiments on a beach drainage system

This research describes a unique set of experiments undertaken at the Large Wave Channel (Hannover) aimed to study the morphodynamic behaviour of a beach face containing a buried drainage system. The advantage of using a large wave flume is that scale effects that affected previous laboratory experiments are minimized. This compares the response of the undrained beach under controlled wave forcing with the response of the drained one with the same wave action. Low, medium and high levels of wave energy were used for the experiments, with significant wave heights of 0.39–0.83 m and wave steepnesses between 0.004 and 0.013. Any positive effect of the drains on the beach face was confined by the position of the cone of depression in the aquifer surface. The best performance of the system was observed with two drains operating at the same time under low to moderate wave energy.