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garoa Harbour, the authors found an increase of sediment resistance by 80 percent at the southern arm of the bar compared to the northern arm. This area was found to be recently affected by sediment erosion, according to visual observations and numerical simulations using ASR Ltd.���s (Raglan, New Zealand) Whaingaroa Harbour model. Subaqueous Dunes. Sediment deA) Measured deceleration (dashed line) and estimated quasistatic bearing capacity equivalent position is displayed by a top layer of compared to lab-based estimates of bearing capacity for the carbonate sand in the shorebreak distinguishable softer sediment on top zone of Kailua Bay, Hawaii. B) Estimate of quasistatic bearing capacity with and without of the substratum, which is unrelated wave action in the big wave channel in Hannover, Germany. Under wave action, the top layer to a steady mud layer on top of sand. loosens up (blue feld). C) Penetration velocity (green line), deceleration (black line) and es- A large number of examples were timated quasistatic bearing capacity in an area of soft sediment accumulation in the Port of found during the survey campaigns. Tauranga, New Zealand. During slack water in the Knudedyb tidal channel, located in the Danish Wadden Sea, sand accumulated along subaqueous tion (as well as quantifying the latter), and assessing changes dunes, which were reworked by strong tides and reached in geotechnical behavior of the different surfcial sediment up to 16 centimeters. At the Stella Passage of the Port of Taulayers. ranga in New Zealand, the authors monitored very soft sediWave-Affected Areas. During measurements in the shorement deposition, reaching a thickness of several centimeters break of Waimanalo and Kailua Bay in Hawaii, the frst hints in the central navigation channel and up to a decimeter on were found for active sediment remobilization under wave the eastern side of the passage. action, refected in the dynamic penetrometer results. This Offshore Wind Farm. At the Alpha Ventus wind energy was confrmed during experiments in the big-wave chantest feld offshore Borkum, Germany, in the North Sea, nel at the Franzius-Institute for Hydraulic, Waterways and six Nimrod surveys were carried out from 2008 to 2011 Coastal Engineering at the Leibniz University of Hanover. to monitor the changing geotechnical signature from the In the wave channel, Nimrod measurements were carscouring around foundations. ried out on medium-sized sand in a water depth of about The results attest variations between different foundation 2.5 meters. Under calm conditions without waves or curdesigns, spatial variability depending on position and the rents, an approximately homogeneous increase of deceleraprevailing current direction, and temporal variability related tion and resulting estimate of QSBC were monitored. Meato the construction history and seasons. surements taken in wave heights of 71 to 78 centimeters, with a wave period of 3.55 to 5.49 seconds, showed that Conclusions and Outlook the sediment resistance in the upper 3 centimeters of the The dynamic penetrometer Nimrod was tested as a comsand decreased, representing a loosening of the uppermost plementary method to support acoustic, standard geotechsediment surface. nical and sedimentological methods in situ during investigaShifting Sandbars. Recent sediment erosion leads to a tions of subaqueous sediment dynamics. It was successfully hard sediment surface after removing all looser particles. deployed from a variety of vessels and platforms in surveys Along the shifting sandbar in front of New Zealand���s Whain- 56 st / FEBRUARY 2013 www.sea-technology.com