MADISON, Wis. (AP) - Jennifer Boehme grew up exploring beaches around her home in St. Petersburg, Florida, looking for whatever she could find. Rocks, sand dollars, coquina molluscs - everything the ocean gave up.
Now, forty years later, Boehme wants to launch another treasure hunt. As executive director of the Great Lakes Observing System, she leads a campaign to map every meter of the lake bottom. The effort, the marine scientist says, will locate hundreds of underwater shipwrecks, highlight topographical features and locate infrastructure. The map, she says, will also help ships avoid underwater hazards, identify fisheries and provide models for erosion, storm surges and flooding as climate change increases.
"One of the things that keeps me going is the idea of the discovery aspect of it," Boehme said. "There is a lot we don't know about the lakes. We know more about the surface of the moon."
Only a fraction of the Great Lakes bottom has been mapped, and those low-resolution maps were completed decades ago, according to the Great Lakes Observing System, a nonprofit organization that manages data from a network of lake observers and makes it easily accessible makes. . The National Oceanic and Atmospheric Administration certified the Great Lakes Observing System in 2016 as meeting federal data collection and management standards, allowing the federal government to use its data without further study.
The organization has been striving since 2018 to create high-resolution maps of all five Great Lakes bottoms, but that's a tall order. The lakes cover 244,106 square kilometers (94,250 square miles) - an area larger than the state of Kansas. Depths range from 210 feet (64 m) in Lake Erie to more than 1,200 feet (396 m) in parts of Lake Superior.
The idea has been gaining momentum since technology has improved and scientists have been mapping the coasts of Florida and the Gulf of Mexico at high resolution over the past three years. Two Michigan congressional representatives - Republican Lisa McClain and Democrat Debbie Dingell - introduced a bill this year that would provide $200 million to map the Great Lakes bottoms by 2030.
"I believe it is 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 lakes took place in the 1970s. Maps are largely created using single-beam sonar technology, similar to today's commercially available depth and fish finders. The system produced maps that covered only about 15% of the bottom of mostly coastal lakes, said Tim Kearns, a spokesman for the Great Lakes Observing System. With a single sound every 500 meters (547 yards), the maps had extremely low resolution and could have missed sinkholes, canyons, sand dunes, shipwrecks and infrastructure such as pipelines, cables and intake pipes, Kearns said.
Fast forward almost half a century. Now scientists and engineers have a range of new mapping tools at their disposal.
One of these is multibeam sonar. Instead of emitting a single sound wave, these systems may bounce hundreds off the bottom. According to NOAA, the technology is so sensitive that it can detect air bubbles in the water.
The only drawback is that systems must be mounted on submersibles or towed under ships to obtain high-resolution images in deep water.
Another tool is laser imaging, in which scientists measure how long it takes for a laser beam fired from an aircraft to reach an object and bounce back, resulting in a three-dimensional imaging of the ground topography.
A high-resolution map of the lake bottom would have several benefits, says Steven Murawski, a biological oceanographer at the University of South Florida who has done extensive bottom mapping of the Florida coast and in the Gulf of Mexico.
The map of the Great Lakes would provide more complete images of bottom features that have changed over the past 50 years due to erosion and drifting sand, giving mariners new depth findings that would improve navigation safety, Murawski said. A map would also help predict how soil characteristics influence storm surges and flooding as climate change continues, which he said would be invaluable to insurance companies and municipal planners.
Improved soil maps would also provide precise locations of infrastructure such as pipelines that have shifted over time, crucial information for dredging and construction projects, Murawski said. He noted that he has mapped about 500 miles (805 kilometers) of pipelines in the western Gulf of Mexico and that "they are never where they should be."
In addition, high-resolution maps could identify underwater bulges and ridges where fish tend to congregate, giving scientists better estimates of the fishing population, the oceanographer added.
Completely mapping the lakes for the first time could also reveal the location of hundreds of shipwrecks - some estimates put the number of Great Lakes wrecks at about 6,000 - and remains of ancient coastal civilizations, Boehme said.
Although momentum for mapping is building, Congress has not acted on the funding bill since the March hearing before the House of Representatives Subcommittee on Water, Wildlife and Fisheries. The subcommittee's chairman, Rep. Cliff Bentz of Oregon, suggested during the hearing that proponents can better articulate the value of a new map.
"I know ranking members suggested that finding the Edmund Fitzgerald would be valuable, 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 actually located several days after the ship. went down.
Bentz's spokesperson, Alexia Stenpzas, did not respond to an email from The Associated Press seeking comment on the bill's prospects.
Boehme said she doubts the bill will gain traction in an election year, but the Great Lakes Observing System is still working toward its 2030 mapping goal. The group holds an annual conference in Traverse City, Michigan, to discuss progress and develop mapping technology. testing, and has contacted any boaters willing to bring mapping equipment to view small portions of the lake bottom.
"This research is for a public good," Boehme said. "The key is persistence and going back again and again and making the case (before Congress). ... We need to understand the system so we can preserve it."
