Storm a-brewin'

Wave runs SBE1 and SBE2 (Sandy Beach Erosion) commenced today. The wave height (originally 0.8 m) increased to 1.0, then to 1.2 m, with an increasing wave period (originally 6.0 s) of 7.0 to 8.0 s. Very exciting stuff! In the video below, a very large wave breaks at around 38 seconds in. 

Everything was going smoothly, the waves were getting higher and we were running ahead of schedule. However, obviously, this would not last long as we managed to over heat the wave paddle and break it. I guess we will not be getting those 1.3 m waves ...

Nonetheless the wave paddle trooped on with 1.2 m waves and the profiles were as expected. Erosion occurred after each run on the beach face (fig. 2) , and the sand bar is migrating seawards (fig.3).  Now that the waves are bigger, water depth has decreased at the sand bar, therefore when the waves break, this energy from the undertow forces sediment back (seawards), hence why we can see the bar gradually retreating. 

The OBS's on rig 2 have also gone a bit crazy, and the data produced looked as if something was blocking the sensors. Reluctantly I jumped into the FREEZING water and i couldn't find anything wrapped around it. However, there were quite a few pebbles on the seabed, meaning they could be being suspended up by the current  or the instruments are being bombarded by pebbles. Either way, hopefully tomorrow we shall get some nice data completing tests Sandy Beach Accretion (SBA1), and we'll try not to break the wave machine!

Figure 1 - Full cross-shore profile.

Figure 2 - Cross-shore profile of the beach face, eroding with every run. (BE11 to 13 = SBE 1) (BE14 to 18 = SBE2).

Figure 3 - Cross-shore profile of the sand bar, showing the front of the bar is eroding and the back of the bar is accreting, migrating seaward