Submersible Survey and Analysis of Video along the Honolulu Seawater Air Conditioning Pipe Route in Support of Their Environmental Impact Statement

Christopher Kelley & Frederic Berg
Hawaii Undersea Research Laboratory, University of Hawaii, United States

Keywords: submersible,SWAC,EIS,GIS,VARS

Honolulu Seawater Air Conditioning, Ltd (HSWAC)is developing a 25,000-ton seawater air conditioning district cooling system for downtown Honolulu. The cold seawater (4-7 °C) will be pumped up to a land-based cooling station from over 544 m depth through a pipe installed on the seafloor. The length of the pipe from the intake to their landfall is 8 km. In 2011, HSWAC contracted the Hawaii Undersea Research Laboratory (HURL) to conduct a submersible survey along their pipe route using HURL’s Pisces 4 and 5 submersibles. The two submersibles each surveyed a 40 m corridor on opposite sides of the pipe route starting at the intake and ending at 250m. The dive video was annotated using VARS (Video Annotation and Reference System) developed by the Monterrey Bay Aquarium Research Institute. All animal observations, substrate types, depths, GPS coordinates, and CTD data, were imported into ArcGIS for layering onto existing HSWAC multibeam and sidescan sonar data. Animal densities within 3 different habitat zones along the pipe route were included in HSWAC’s Environment Impact Statement (EIS) for the purpose of evaluating the potential impacts of the pipe on the deep water biological communities at the site.

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