Hydrography (Diving Deeper podcast, 7.15.09)
Collision with vessels is the leading human-caused source of mortality for the endangered North Atlantic right whale.
Several hydrographic surveys managed by NOAA’s Office of Coast Survey recently reached important milestones.
In July, Coast Survey acquired hydrographic survey data that will help protect North Atlantic Right Whale calves. The survey covers a proposed new route for vessel traffic that will bypass the critical calving area around the approach to Brunswick, Ga. Federal and state officials, in collaboration with local stakeholders, will assess the results and finalize plans to revise the traffic fairways. Coast Survey charted a similar whale avoidance route in and out of Cape Cod Bay in 2006.
Another hydrographic survey began for a coastal traffic route off northern Virginia. This work builds on an ongoing effort to resurvey and update the nautical charts of the busy coastal commercial traffic routes along the eastern seaboard.
Coast Survey conducts hydrographic surveys to ensure safe, efficient, and environmentally sound marine transportation that brings an uninterrupted flow of people and goods into and out of our nation’s ports.
Farther north, hydrographers on the NOAA ship Fairweather are surveying in the Bering Straits around Cape Prince of Wales, to detect navigational dangers in critical Arctic waters that have not been charted for more than 50 years. The team is examining sea floor features, measuring ocean depths, and supplying data for updating NOAA’s nautical charts spanning 350 square nautical miles. The data will also support scientific research on essential fish habitat and will establish new tidal datums in the region.
The Office of Coast Survey annually prioritizes areas that need hydrographic surveys (pdf, 8.6 MB). Of the 3.4 million square nautical miles (SNM) of the U.S. Exclusive Economic Zone, approximately half a million SNM are navigationally significant. NOAA has identified 43,000 SNM as critical areas, and is surveying 2,850 SNM in 2010.Hydrography is the science that deals with the measurement and description of the physical features of bodies of water and the land areas affected by those bodies of water. A hydrographic survey may be conducted to support a variety of activities including nautical charting, port and harbor maintenance (dredging), coastal engineering (beach erosion and replenishment studies), coastal zone management, and offshore resource development.