BARDEX LOGBOOK 10/07/08 - 11/07/08

Thursday 10/07/08

The rest of series C3 [15,15,20,5] was carried out, with the usual profiles, rig adjustments and sediment photos.
Offshore rig removed, data downloaded.
30 mins of design waves for this sequence – 2.5 sea, 2.5 lagoon, Hs=0.8, Tp=3s.
Water levels prepared for the next set of tests –

Then series C4 began (high lagoon 3.5, sea=2.5, hs=0.8, tp=3) and half the run completed
[5,5,5,5,10]. Note that when the series ends unfinished we continue to log the delatres pressure transducers overnight in a separate file (to keep file sizes down!) in order to log the beach groundwater table response back to equillibrium


Friday 10/07/08

Finished series C4 with [10,15,15,20,5mono] waves, with usual rig adjustments, profiles and sediment photos. It has been noted that the 3s waves cause little morphological change compared to 6s period waves, apart from on the monochromatic waves of 3s which cause large erosion (c.5-10cm in 5mins), possibly because the swash excursions are so small with 3s waves, the volume of water contained in them being very small

The 3s waves caused much more obvious sediment grading patterns compared with the longer waves. C4 saw armouring of the beachface, before the monochromatic waves removed the coarse particles on the surface offshore to the breakpoint

Offshore rig reprogrammed to start recording on Monday 9am

Total station survey of all instruments, inc EMs, PTs, camera, weather station, all rig instruments (heights relative to known points on rig).

Five 25cm-long sediment cores taken for geotechnical analysis, and their positions surveyed in. All EMs washed

Lagoon and sea pumped to 2.5m. 3mins of reset waves (1m, 10s) to remove berm in readiness for the nest series.

Trial of A3 started at 15:00. Took 35 mins to raise sea level from 2.5m to 3.25m, pumping in at 100%. Took 25 mins to pump back down again – not symmetrical because of differences in the pumps.

Monday can begin with offshore rig deployment followed by test A3