Researchers Resurvey Ship Grounding Site off South Shore of Oahu

Recently, scientists in the PIFSC Coral Reef Ecosystem Division (CRED) completed a small-boat mission (SB-13-25) during which they resurveyed the grounding site of the USS Port Royal, which ran aground in February 2009 nearly 1 km south of Reef Runway off the south shore of Oahu. The work was requested by the State of Hawaii, Department of Land and Natural Resources (DLNR).

Bathymetry around the USS Port Royal grounding site as measured using multibeam sonar during a 2010 survey by the CRED 
        mapping team.
Bathymetry around the USS Port Royal grounding site as measured using multibeam sonar during a 2010 survey by the CRED mapping team.

On January 9, 2014, CRED staff members Frances Lichowski, Faith Knighton, Rhonda Suka, Jeremy Taylor, and John Rooney used the NOAA R/V AHI, to collect acoustic data and video and still imagery of the seafloor with a Reson SeaBat 8101 multibeam echosounder and a camera sled.

The original goal of this mission also was accomplished: the team installed and conducted a patch test to calibrate the SeaBat 8101 echosounder on the R/V AHI and made sure the vessel and equipment were ready for subsequent acoustic and optical surveying around Maui (planned for February). In addition, the team tested a new strobe light for the CRED camera sled (called a "TOAD", for towed optical assessment device) under survey conditions and made adjustments to camera settings to improve the quality of still imagery collected by the sled.

The acoustic and optical data collected on January 9 and during later surveys will help fill gaps in existing data sets, enhancing their utility for spatially based management of the resources of coral reef ecosystems.

The accompanying map shows bathymetry (data on the depths and shapes of underwater terrain) at the grounding site of the USS Port Royal from an earlier survey, conducted by the CRED mapping team in December 2010 using a multibeam sonar, also at the request of DLNR. Bathymetry grids from both the 2010 and 2014 surveys will be compared to look for movement of rubble or other changes during the intervening period.