NOAA Ship Rainier recently arrived off the Santa Barbara coast to complete hydrographic surveys at NOAA’s Channel Islands National Marine Sanctuary (CINMS) as part of the Southern California Seafloor Mapping Initiative. Over the next month, the ship will use their new multibeam echo sounders to support safe navigation and update nautical charts for the sanctuary. In addition to providing data for crucial nautical chart updates, the surveys will also generate backscatter imagery, which the sanctuary uses for habitat mapping.
Up until 2014, more than 50 percent of the sanctuary was not charted at a suitable scale for making informed resource management decisions. NOAA launched the Southern California Seafloor Mapping Initiative to address this information gap and identify priority areas to survey. To begin filling this data gap, NOAA relied on its local vessels equipped with ship-mounted sonars optimized for fisheries research, as well as state and federal partner resources. Coast Survey’s autonomous underwater vehicle (AUV) was also used to collect data in deep sea coral areas. Fast forward to the fall of 2017, and just less than 25 percent of the sanctuary— primarily shallow and near shore areas—remains to be charted using modern technology.
“The near-shore areas within the sanctuary were last surveyed using lead line techniques in the 1930s,” said Cmdr. Ben Evans, commanding officer of NOAA Ship Rainier. “The technology we have today enables us to improve our nautical charts and navigation safety while at the same time providing the critical habitat data the sanctuary needs to manage its resources.”
Rainier is one of NOAA’s four large hydrographic ships and is equipped with four survey launches designed to survey shallow water areas. This equipment, coupled with the surveying expertise on board, makes Rainier the ideal vessel to support this initiative.
Rainier started its survey work in the sanctuary around San Miguel Island, the westernmost island in the Channel Islands chain. San Miguel is situated off the coast of Point Conception, where the open Pacific Ocean meets the Santa Barbara Channel. The area is windswept, as evidenced by the ribbons of sand seen up the island’s hillsides and rough seas off the coast.
With safety and quality data collection top priorities for Rainier, two important tasks were completed before the vessel commenced survey operations around the island. Rainier deployed a skiff—a small boat with a 4-person crew—to perform inshore reconnaissance to determine the safety limits for conducting inshore mapping. This is particularly important as some features around the shoreline may not have been charted accurately or at all during the previous lead line surveys. Put simply, the crew searched for hazards such as rocks and thick kelp beds at low tide so the survey launches can avoid them while surveying at high tide.
Video: Timelapse of shoreline reconnaissance in Cuyler Harbor, San Miguel Island.
The ship also deployed one of its survey launches to locate a safe anchorage for the ship, and test its backscatter collection capabilities. Although the launches’ new sonars were calibrated after installation in Puget Sound just a few weeks prior, the crew needed to confirm and fine-tune the systems for operation in the CINMS. This local calibration also ensured backscatter imagery would be consistent between the four survey launches.
Once these initial tasks were complete, day-long survey operations commenced the following day. Rainier will survey the near-shore areas of the sanctuary for the next four weeks.
NOAA ship Rainier, a 49-year-old survey vessel, is part of the NOAA fleet of ships operated, managed, and maintained by NOAA’s Office of Marine and Aviation Operations, which includes commissioned officers of the NOAA Corps, one of the seven uniformed services of the United States, and civilian wage mariners.