Multibeam Survey Helps Fill Gaps in High-resolution Bathymetry around Oahu

The PIFSC benthic habitat mapping team recently conducted a 3-week survey of the seafloor around the island of Oahu with the NOAA R/V AHI, an 8-m survey launch. Equipped with a 240-kHz Reson SeaBat 8101 ER multibeam echosounder and associated equipment, the R/V AHI has been used to collect seafloor depth data, or bathymetry, around many of the islands in the Hawaiian Archipelago, American Samoa, the Pacific Remote Island Areas (Palmyra, Johnston, and Wake Atolls; Howland, Baker, and Jarvis Islands; and Kingman Reef), and the Mariana Archipelago (Guam and the Commonwealth of the Northern Mariana Islands). The survey was funded by NOAA's Coral Reef Conservation Program.

The purpose of the recent survey, denoted PIFSC small-boat mission SB-13-11, was to fill gaps in existing high-resolution bathymetry around Oahu. Large research ships—such as the R/V Kilo Moana, operated by the University of Hawaiʻi at Mānoa, or the NOAA Ship Hiʻialakai—have collected bathymetry data at depths >200 m around the islands of the Hawaiian Archipelago but they are unable to safely navigate close to shore, where most reef ecosystems are found.

In this image of seafloor depth around Oahu, the small black areas indicate locations that were surveyed during the June 17-July 3, 
               2013 mission of the R/V AHI to collect high-resolution bathymetry data at depths <200 m.
In this image of seafloor depth around Oahu, the small black areas indicate locations that were surveyed during the June 17-July 3, 2013 mission of the R/V AHI to collect high-resolution bathymetry data at depths <200 m.

From June 17 to July 3, 2013, CRED staff collected bathymetry data around Oahu at depths shallower than about 200 m (660 ft). Survey data are being processed and should be available in December 2013 when they will be provided to partners at the Hawaii Mapping Research Group (HMRG) in the School of Ocean and Earth Science and Technology at the University of Hawaiʻi at Mānoa. The new bathymetry data will become part of a synthesis of high-resolution bathymetry data around the main Hawaiian Islands that HMRG maintains and makes freely available on their website.

The processed data also will be provided to NOAA's National Geophysical Data Center, which also maintains a website where bathymetry data can be downloaded.