Oʻahu

Landsat satellite image from NASA

Oʻahu encompasses 1546 sq km (597 sq mi) and is the third largest in the chain. Also known as The Gathering Place, Oʻahu draws more visitors than any of the other Hawaiian Islands. The island was formed from joining of the Wai‘anae and Ko‘olau volcanoes. Coral reefs surround the island, although active live coral growth is limited to the leeward sides of the island or in sheltered areas on the windward coasts. Reef structures on the north shore help form the waves that draw surfers worldwide.

Underwater video groundtruthing of SHOALS data for benthic habitat mapping
U.S. Geological Survey Open-File Report 2005-1244
Summary and preliminary interpretations of USGS cruise A-2-02-HW: Underwater video surveys collected off of Oʻahu, Molokaʻi, and Maui, Hawaiʻi, June-July 2002

Scientists from the USGS Hawaiʻi Coral Reef Project are working closely with Malama Maunalua and the Kewalo Marine Laboratory, as part of the Hawaiʻi Local Action Strategy Plan, to investigate poor water quality issues in Maunalua Bay on the southeast coast of Oʻahu. This coral-lined embayment has seen a dramatic decline in ecosystem health, including sedimentation, invasive algae species, and a reduction in reef fish. A major factor in the decline of ecosystem health is human-induced changes on land, mainly from engineering of natural drainage gulches that have become concrete-lined channels. These channels speed up the flow of storm runoff from the uplands, increasing the discharge of freshwater, sediment and other land-based pollutants to the bay. The USGS has been instrumental in measuring water-column properties in Maunalua Bay, including waves, currents, water levels, termperature, salinity, and turbidity, to provide insight into the transport and fate of these contaminents.

U.S. Geological Survey Open-File Report 2010-1217
Coastal circulation and sediment dynamics in Maunalua Bay, Oʻahu, Hawaiʻi; Measurements of waves, currents, temperature, salinity, and turbidity; November 2008-February 2009
U.S. Geological Survey Open-File Report 2012-1040
Presto, M.K., Storlazzi, C.D., Logan, J.B., Reiss, T.E., and Rosenberger, K.J., 2012, Coastal Circulation and Potential Coral-larval Dispersal in Maunalua Bay, Oʻahu, Hawaii—Measurements of Waves, Currents, Temperature, and Salinity, June–September 2010

We have also assisted the National Park Service (NPS) with documentation of underwater conditions around the USS Arizona Memorial in Pearl Harbor. Of special concern is the fact that the hull of the USS Arizona is deteriorating and has the potential of releasing more than half a million gallons of fuel oil into the environment. By using the same instrumentation packages that we use to monitor oceanographic conditions on coral reefs, such as currents, waves, temperature and salinity, we can help the NPS get a handle on the physical dynamics surrounding the submerged hull. For more information on this off-shoot project click on the links below.

USGS Researchers Collaborate with National Park Service Archeologists to Better Predict the Life Expectancy of the USS Arizona
Dynamics of the Physical Environment at the USS Arizona Memorial: 2002 - 2004, USGS Open-File Report 2004-1353
USS Arizona Memorial (National Park Service website)
USS Arizona Preservation Project 2004 (National Park Service website)