U.S. waters cover 3.4 million square nautical miles, including a sea floor that is constantly changing due to storms, erosion, and development. To keep the nation's suite of over a thousand nautical charts up to date, the Office of Coast Survey annually plans hydrographic survey projects to measure water depths and identify new navigational hazards. Survey planners consider requests by marine pilots, port authorities, the U.S. Coast Guard, the boating community, and others when setting the year's schedule.
2016 hydrographic surveys will be conducted by NOAA's four dedicated survey ships—Thomas Jefferson, Ferdinand Hassler, Rainier, and Fairweather—and private companies that survey on a contract basis with NOAA. The NOAA ships are operated and maintained by the Office of Marine and Aviation Operations, with hydrographic survey projects managed by the Office of Coast Survey.