Survey of Rhode Island Sound for SAMP


URI GSO researchers John King, Robert Pockalny, Monique LaFrance, Fred Hegg and Cam Morrisette embarked on an eight day cruise on the Environmental Protection Agency’s Ocean Survey Vessel Bold to conduct an assessment of the seabed in Rhode Island Sound.

The team mapped seventy-five square miles of federal waters in the “Area of Mutual Interest” identified in the Rhode Island Ocean Special Area Management Plan, detailing the bathymetry (underwater terrain) in high resolution using interferometric sonar and sub-bottom profilers. Interferometric sonar simultaneously produces a bathymetry (water depth) map and a side scan (surface geology) map. The sub-bottom sonar produces data on the subsurface depth of layers and their likely engineering properties. The data may be used to inform decision makers about the ease of installation and optimal placement of wind turbines in the area.

The mapping focused on the Cox Ledge, an area that is a glacial moraine, a place where ancient glaciers deposited soil and rock debris.  As a result, large boulders are not uncommon in the area. Areas south of the moraine were also mapped. Since wind turbines will need to be anchored using pilings (supports that extend 50 to 60 meters (164 to 196 feet) into the seabed), the “sub-bottom” data gathered by King’s group will be crucial. The bathymetry and side scan sonar data will be used to identify areas of valuable habitat and potential user conflicts.

About halfway through the mapping, the project appeared to be in jeopardy when a pole supporting the sonar system snapped.  Fortunately, a welder from Bold‘s crew was able to repair the pole, eliminating the need to return to port, and the mapping continued after a relatively short delay.

Funding for the cruise was provided by the Department of Energy, via the State of Rhode Island Office of Energy Resources.