Nome area’s seafloor maps will see an upgrade
NOAA is updating its underwater maps around Nome in anticipation of the city’s port expansion.
Lieutenant Caroline Wilkinson, the regional navigation manager for Alaska with NOAA’s Office of Coast Survey, visited Nome during the Western Alaska Interdisciplinary Science Conference earlier this month.
The area directly outside Nome’s harbor was last surveyed in 2005, but the wider area representing the approach to Nome hadn’t been surveyed since 1930, Wilkinson said. A century ago, the technology used for this survey was a handheld lead line.
“Obviously the data was old—it needed to be redone,” Wilkinson said.
The updates are also necessary, she said, as marine traffic is expected to increase in this area once the Port of Nome is expanded.
“We wanted to make sure that we have good data to respond to that increased traffic and that construction project,” Wilkinson said.
The Office of Coast Survey contracted with the private company Woolpert to complete this new bathymetry survey.
Woolpert used the R/V Thunder and R/V Norseman II to collect its data, as well as a pair of unmanned research vessels that could autonomously scan the seafloor. These vehicles could be sent into shallow and uncharted areas more safely than a larger vessel with crew on board, Wilkinson said.
She added that the use of these seafaring surface drones was crucial in expanding the footprint of a survey that had to take place in the relatively short timeframe of the ice-free season.
“Even though it may not have looked like the largest survey…this was a huge survey,” Wilkinson said.
Over 90 days, the team collected data for 1,700 square nautical miles. They used Starlink satellite internet to help pilot some of the autonomous vessels and to send the data they collected to be quickly processed in Anchorage.
A full coverage survey was completed in a square-shaped area outside the port of Nome. In the rest of the offshore area between Golovin Bay and Cape Woolley, the contractors completed what’s called a partial coverage survey.
“You aren’t getting 100 percent of the area below, but you’re close enough that you are getting good depth representation,” Wilkinson said.
The bathymetric data acquired as part of the project are still under final checks and reviews, but the Office of Coast Survey will be updating its navigation products in the next few months to incorporate this new information, Wilkinsons said. The data will eventually be publicly available for download from NOAA’s National Centers for Environmental Information.
Navigation officials said that their preliminary analysis of the survey data from Nome hasn’t turned up any surprises or previously unknown hazards.
“We did not see any surprises or dangers to navigation, which is great,” Michael Stephens, who is the contracts team lead at the Office of Coast Survey, told the Nugget in an email. “Even though we did not find any surprises or dangers to navigation, collecting up to date digital depth and feature data is important to ensure safe navigation in the region.”
NOAA is the federal agency responsible for surveying the ocean and some navigable rivers and lakes, and the Office of Coast Survey was originally mandated to map the ocean floor for safe navigation. That means much of the office’s survey priorities have centered on mapping areas of high vessel traffic. But Wilkinson said bathymetric data is increasingly important for modeling, too. Scientists can use these underwater maps to try to better understand risks like tsunami inundation and storm inundation for coastal communities.
Wilkinson told members of the audience to reach out to her if they know of an area with outdated maps that should be prioritized.
“Right now 63 percent of U.S. waters off Alaska are unmapped,” she said. “As of January 2023, that number was 66, so we are going in the right direction.”
But getting Alaska’s coast entirely maps is estimated to cost $1 billion, she said.
“Part of the cost is building the capacity to do it,” Wilkinsons explained. “Right now, NOAA has two vessels that operate seasonally in Alaska, one of which just suffered a shipboard fire, and so she will not be out this next summer. And both of them were built before 1960.”
There are also only a few private companies NOAA contracts with that can do this work in Alaska, and many of them aren’t equipped to work in remote locations. For example, Wilkinson said her office is hoping to survey the seafloor around St. Lawrence Island in the near future, but that can only be done by a NOAA ship, “because it’s the only survey vessel large enough to bring the amount of people out there we need to survey the waters.”
This summer, the office’s Alaska work will include new surveys around Kotzebue and along the proposed route that deep draft vessels would be shuttled towards as they leave Nome and go around the North Slope.