MADISON, Wis. — Jennifer Boehme grew up scouting the beaches around her home in St. Petersburg, Florida, for anything they can find. Rocks, sand dollars, coquina molluscs – whatever the sea provides.
Now, 40 years later, Boehme wants to launch another treasure hunt. As executive director of the Great Lakes Observing System, he led a campaign to map every meter of lake bottom. The effort, marine scientists say, will identify hundreds of underwater shipwrecks, illuminate topographic features and locate infrastructure. The map, he said, would also help ships avoid sinking hazards, identify fisheries and provide information on erosion, storm surge and flood models as climate change worsens.
“One of the things that keeps me going is the idea of the discovery aspect,” Boehme said. “There’s a lot we don’t know about lakes. We know more about the surface of the moon.”
Only a fraction of the bottom of the Great Lakes’ has been mapped, and the low-resolution chart was completed decades ago, according to the Great Lakes Observing System, a non-profit that organizes data from the lake’s observatory network and makes it easily accessible. . The National Oceanic and Atmospheric Administration certified the Great Lakes Observing System in 2016 as the federal standard for data collection and management, allowing the federal government to use the data without further review.
The organization has been pushing since 2018 to create high-resolution maps of all five Great Lakes basins, but it’s a daunting task. The lake covers an area of 94,250 square miles (244,106 square kilometers) – an area larger than the state of Kansas. Depths range from 210 feet (64 meters) in Lake Erie to more than 1,300 feet (396 meters) in parts of Lake Superior.
The idea is gaining traction as technology improves and scientists have completed high-resolution mapping of the Florida and Gulf of Mexico coastlines over the past three years. Two congressional representatives from Michigan – Republican Lisa McClain and Democrat Debbie Dingell – introduced a bill this year that would allocate $200 million to create a basic map of the Great Lakes by 2030.
“I believe it’s time to take the exploration and discovery of the Great Lakes into our own hands,” McClain said during a House subcommittee hearing in March.
The last attempt to map the lake came in the 1970s. Maps are generally created using single beam sonar technology similar to fish and depth finders available commercially today. The system produces maps of only about 15% of the bottom of coastal lakes, said Tim Kearns, a spokesman for the Great Lakes Observing System. With one sounding every 500 meters (547 yards), the map has very low resolution and may miss sink holes, canyons, sand dunes, shipwrecks and infrastructure such as pipes, cables and intake pipes, Kearns said.
Fast forward nearly half a century. Today scientists and engineers have a variety of new mapping tools.
One of them is multibeam sonar. Instead of sending a single sound wave, this system can bounce hundreds from below. The technology is very sensitive and can detect air bubbles in the water, according to NOAA.
The only drawback is that the system must be installed on submersibles or towed on board to take high-resolution images in deep water.
Another tool is laser imaging, where scientists measure how long it takes for a laser beam fired from an aircraft to reach an object and bounce back, which produces three-dimensional imaging of the bottom topography.
A high-resolution map of the lake’s surface would provide multiple benefits, said Steven Murawski, a biological oceanographer at the University of South Florida who has done bottom mapping of the Florida and Gulf of Mexico coasts.
The Great Lakes map will provide a more complete picture of bottom features that have changed over the past 50 years due to erosion and sand shifting, providing new depth discoveries that will improve boating safety, Murawski said. A map will also help predict how the bottom features affect storms and floods as climate change continues, which he said will be invaluable information for insurance companies and municipal planners.
Better bottom maps will also provide the exact location of infrastructure such as pipelines that have changed over time, important information for dredging and construction projects, Murawski said. He noted that he has mapped about 50,000 miles (805 kilometers) of pipeline in the western Gulf of Mexico and “it’s not going anywhere.”
In addition, the high-resolution maps will identify underwater outcroppings and edges where fish tend to congregate, allowing scientists to get better estimates of fishery populations, the oceanographer added.
Mapping the lake for the first time could also reveal the location of hundreds of shipwrecks — some estimates put the number of Great Lakes wrecks at around 6,000 — and relics of ancient coastal civilizations, Boehme said.
Although momentum for mapping is growing, Congress has not acted on the funding bill since a March hearing before the Natural Resources Subcommittee on Water, Wildlife and Fisheries. Chairman of the subcommittee, Rep. Cliff Bentz of Oregon, suggested during the hearing that proponents should do a better job of articulating the value of the new map.
“I know the ranking members were advised to find the Edmund Fitzgerald would be an expensive thing, but there has to be more to it than that,” Bentz said, referring to the cargo ship that sank in Lake Superior in 1975. The wreck was found days after the ship. down.
Bentz’s spokeswoman, Alexia Stenpzas, did not respond to an email from The Associated Press seeking comment on the bill’s prospects.
Boehme said he doubts the bill will gain traction in an election year, but the Great Lakes Observing System could still meet its 2030 mapping goal. boaters who want to take mapping equipment, provide a small view of the lakebed.
“This research is in the public interest,” Boehme said. “The key is persistence and coming back and making the case (to Congress). … We need to understand the system in order to preserve it.”
