By mapping uncharted territory, a team of Middlebury researchers has discovered a notorious traitor's ship, a new state boundary, and the answers for cleaner water.
By Gretel H. Schueller
For more than five hours on October 11, 1776, cannon fire roared across Lake Champlain. In the narrow strait between the New York mainland and tiny Valcour Island, a ragtag squadron of 15 American ships commanded by a still-loyal Benedict Arnold battled a goliath British fleet. Although Arnold's fleet was vastly outmatched and suffered tremendous losses (including Arnold's own gunboat, the Spitfire), the fledgling American navy effectively thwarted the British attempt to advance down Lake Champlain to the Hudson River, and managed to retreat under the cover of darkness.
Today, some two centuries later, residents peacefully sail, kayak, or travel by ferry across the lake. And while most people are entranced by the surrounding mountain ranges and placid water, the calm, steely blue surface of Lake Champlain is deceptive. Plunge past its watery skin and you'll start to uncover a dark, silt-covered terrain—in some places more than 400 feet deep—that is scattered with relics of bloody battles and deadly storms. In fact, this 435-square-mile lake holds the country's largest and best-preserved collection of historical ships—from Native American dugout canoes and British warships to 19th-century tugboats and even a horse-powered ferry. Researchers estimate that as many as 300 shipwrecks could be entombed in these waters.
Yet until recently, less than 10 percent of the lake's floor had been charted, making the bottom of Champlain as mysterious as the surface of Mars. That is until geology professors Pat and Tom Manley completed a 10-year project this summer that has resulted in the first comprehensive map of the lake's floor.
The last time anyone had charted the lake's terrain was in 1879, when casting lines with lead sinkers were used to measure depths at roughly 9,800 points across the lake. By contrast, the Manley's map contains more than 735,000 measurements and covers about 95 percent of the lake's bottom. This quantum-leap improvement compares to upgrading from a pencil sketch to a color photograph. Not only is the map more detailed, Pat noted, "It also corrects some inaccuracies of the original measurements." In some areas, such as Shelburne Bay, researchers found as much as an eight-foot difference. The new map could also raise some interesting political implications, she said. "The standard boundary between New York and Vermont follows the deepest parts of the lake. Now, with this map, it could be revised."
The map spans more than eight feet and is currently hanging on a wall on the fourth floor of McCardell Bicentennial Hall. In vivid red and cool shades of green and blue, the map paints a picture of plunging valleys, underwater shoals, old river channels, and plateaus—some previously unknown. If one were to look at it with a pair of 3-D glasses, the surface would explode into three dimensions. On a late summer afternoon, the Manleys sat in their Bi Hall laboratory and related their decade-long adventure of mapping Champlain's floor.
Both were soft-spoken and finished each other's sentences. Tom Manley stretched back in his chair, swiveling between a pair of computer screens. Every few minutes his computer chimed the arrival of a new e-mail. He was wearing jeans and sturdy, black leather boots. "I rode my motorcycle in, and I haven't had a chance to change," he almost sheepishly explained. Normally, he wears shorts—regardless of the weather. It's a relic of his earlier days of polar research, which explains the large collection of all things polar bear on his windowsill. With an impish grin, Manley claimed that the one day he did wear long pants he caught a cold.
Pat rolled her eyes and laughed. She's tall, with long auburn hair, and has a sharp sense of humor. (The sign outside her office door declares "Reunite Gondwanaland!") The Manleys have known each other since their undergraduate days as geology majors at Kent State University, in Ohio. They honeymooned at a field camp in the Black Hills of South Dakota more than 30 years ago, and have shared a passion for geology ever since.
They acknowledged that it's somewhat out of the ordinary for two geologists—who primarily focus on water circulation and sedimentation patterns—to become so well versed in underwater archaeology and state boundaries, but sometimes one's research follows the most unconventional routes.
About 10 years ago, as the Manleys were expressing an interest in discerning a more precise picture of the lake's floor, the Lake Champlain Maritime Museum wanted to conduct a systematic inventory of all the lake's hidden shipwrecks. Around that time, a small but destructive creature—the zebra mussel—had infiltrated the lake and had begun encrusting entire shipwrecks in layers; some divers compared the look to a vessel covered in shag carpeting. The mussels would not only affect sites visually, but would also allow sulfur-reducing bacteria to thrive, thereby changing the water chemistry, which quickly dissolves iron fastenings. The museum didn't have the ability to conduct a survey on such a large scale, says its executive director, Art Cohn, yet the urgency was inescapable; the damage wrought by the mussels was worsening each summer. And that's when Cohn heard about the Manleys and their interest in mapping the lake's floor. The Manleys also had a side-scan sonar. Towed behind a ship, the yellow torpedo-shaped instrument creates images, called acoustic shadows, of any features that stick up above the surrounding floor, such as a ridge—or a shipwreck. It was a perfect fit.
For eight consecutive summers, the Manleys and a team consisting of student researchers, a navigator, and a lake historian would board the Neptune, a 40-foot, steel-hulled ship privately owned and operated by a Vermont captain, and crawl along the lake's surface at five miles an hour, while the side-scan sonar transmitted images to two of the five computer screens in the ship's cabin. ("People think being out on the lake is so glamorous. It's tedious. You're in a box staring at a computer screen for 8 to 10 hours a day," explains Pat.) The team would traverse the 120-mile-long lake in rows—Tom likened it to mowing several football fields with a push mower—and while the sonar transmitted images to the computer screens, depth-finding equipment would gauge the depth and position every two seconds.
That first summer, the team discovered 10 new shipwrecks; five of them were infested with zebra mussels. It was the next summer, however, that the team made its most intriguing discovery. As they were crisscrossing the lake one morning, someone on board spotted an unusual image on one of the computer monitors; to the untrained eye, it looked like the grainy outline of a peapod, but the scientists had a hunch they were on to something important. The next d
ay, Cohn joined the dive team to investigate the new find. The object rested in cold, deep water, where neither light nor sound penetrated. Flashlights cast a murky green tinge. The only noise was the burble of bubbles as each diver exhaled. Cohn, a veteran diver of nearly 40 years, describes the underwater site as "a little eerie."
Upon reaching the lake floor, Cohn knew immediately what they had found. It was a Revolutionary War gunboat, 54 feet long, with a 50-foot mast and bow cannon still in place, and it was sitting upright as if it were ready to sail along the muddy lake floor. Upon surfacing, his first words to his colleagues were: "We found the missing gunboat!"—Benedict Arnold's missing Spitfire, which hasn't seen the light of day since he abandoned it in the night nearly 230 years ago. That evening when Pat Manley came home, she put the side-scan-sonar image on the kitchen table in front of her husband (after working for two straight weeks, it was the one day he wasn't aboard). "All I could say," Tom recalls, "was wow!"
"The Spitfire is an extraordinary object tied to an extraordinary event. It's a national treasure," states Cohn. It is just one of nearly 80 shipwrecks that the team has discovered because of the mapping project. "There's decades worth of work to do for us," says Chris Sabick, director of conservation at the Maritime Museum. With a team of divers, Sabick and his colleagues are steadily examining the new discoveries, researching their histories, and preserving any artifacts. "All these sites get reported to determine their underwater preservation potential."
Of course, the Manleys' main interest centers on understanding how water and sediment circulate through the lake. "You can slosh water around in a bucket, but if it has a hole, the water will flow differently," explains Pat Manley. "Currents respond to topography." Like a hole, underwater ridges change water circulation. Currents also carry sediment or pollutants like phosphorus or mercury, and the Manleys hope their work will provide better information on where mercury and sediment settle. Tom has been working with the Champlain Water District to determine the best location for a new intake pipe in Shelburne Bay, one of the main municipal water supply sources in the area. The current pipe sits just behind White's Ridge, a newly discovered ridge of sediment that runs halfway across the northeast portion of the bay; this location, behind the ridge, modifies circulation patterns, which can affect water quality. A nearby shipwreck will also factor into the position of the new pipe.
This year, Tom spent most of the summer in St. Albans Bay studying the impact wind has on the lake's circulation patterns. Once a week, as the sun rose, he'd unload his yellow truck and fill a small Zodiac boat with computer equipment, and then motor from Kill Kare State Park to Burton Island, where the Baldwin, the College's 32-foot research vessel, was docked. Four satellite-tracked buoys would be drifting five to 30 meters below the surface, and at precisely 8:00 a.m., they'd pop to the surface. "We never know where, though," he laughed on one such morning, as he scanned the flat surface of the lake at around 7:55, five minutes before the buoys were scheduled to surface. Since he had released them a week earlier, they'd been on the move, riding currents fueled by the wind. Like a treasure hunt, the only guide was a beacon finder that informed you if you were "hot or cold" on a scale of 0 to 100. A flag topped each buoy, and for several hours, Tom scanned the horizon for Day-Glo-orange specks. ("Luckily the water is calm today. You should try doing this with sizable waves around," he said.)
"There it is!"
Bobbing along the shore was the first buoy. Tom climbed into the Zodiac, which was tethered alongside the Baldwin, and zipped to the buoy. A heron sat on a nearby rock, and Tom greeted the bird with a friendly "Hi, guy!" Tom has a little of that goofy geek to him, and that morning he chattered away not just to the bird, but also to the GPS system, the buoys, even the duct tape he used onboard the Baldwin. After a lot of circling and zigzagging, all four buoys were back on board, and Manley returned to the lab, where he would eventually analyze the mountain of information that detailed how the buoys traveled.
Today, layers of 10-foot-long maps cover a table in the Manley's Bi Hall lab. "There's tons of data. All this stuff had to be organized and put into this program so we could visualize it. We must have gone over each point 10 times, and there were more than 700,000 points," explains Burch Fisher '03. Fisher became a geology major after taking Tom's oceanography course in the fall of 2002 and spent last year working in the Manleys' lab as a research assistant. "One of the coolest things—and a real testament to Middlebury—is the collaboration between students and faculty," Fisher says. "The map is a great example of that. Getting a more intimate knowledge of the lake and finding a way to visualize something that hadn't been done before was really rewarding." Fisher's at Dartmouth now, where he's studying for a master's in earth science. "That map is going to be around for a long time."
During the past decade, a number of students have assisted the Manleys. One, Laura Kelly '06, discovered a rise of land south of Four Brothers Islands, which is now officially named Kelly Rise. "It's important to recognize the collaboration among a talented group of scientists, archaeological dive team, and students," Cohn says. "I really give them [the Manleys] high marks for involving students in real-world research."
Since the map was presented last summer, public response has been overwhelming. Copies are now hanging at the Maritime Museum and at the Echo Center in Burlington. The next step, now in the works, is to create a Web site so that the information and map will be available to everyone.
The Manleys are also gearing up for another summer on the lake to fill in a few remaining holes in their research. "There's still a lot more down there," Tom says. They are certain there is one thing not waiting to be discovered, however: Lake Champlain's legendary deep-water creature, Champ. "I can't say that I'm convinced! Scientifically, there are just too many reasons why it could not exist in Lake Champlain."
Gretel H. Schueller writes about science and nature for a number of publications, including Adirondack Explorer, Audubon, National Wildlife, and Popular Science. She lives outside of Burlington, Vermont, not far from the shores of Lake Champlain.