“This is like a big colonoscopy,” Tim Clancy told a crowd of about 65 at the Hopatcong Civic Center on Friday night. “We want it to come back clear, but if it does come back with something, we want to deal with it.” So far, the water chestnut—an invasive species that can destroy natural habitats and has already wreaked havoc on Lake Musconetcong—has not been discovered in Lake Hopatcong. But its proliferation just downstream in Musconetcong and in other regional bodies of water has lake advocates worried that the weed could take over—particularly in the lake’s shallower, more stagnant waters—and damage the natural environment and the recreational opportunities. In an effort to proactively address the potential problem, rather than react to a crisis in the coming years, the Knee Deep Club has partnered with paddling groups around the lake to search Lake Hopatcong for any sign of the fast-growing weed. “Those of you who paddle are best suited for this effort,” Clancy told the volunteers, who packed the center’s meeting room immediately following the Knee Deep Club’s monthly meeting. “When you’re kayaking, you can’t be more in the lake unless you’re swimming, and you’re in tune with the environment. We need you to be our eyes to find this critter.” The critter itself is pretty distinctive: it starts with a seed that has four barb-like prongs, which can be transmitted to the lake by boaters or by sticking to the feathers of geese, ducks, and other birds. Once the seed embeds itself in the lake bottom (particularly shallow areas without much turbulence), a stringy plant grows toward the surface, creating clusters of leaves called rosettes. Each leaf is about 2 inches wide, serrated with an arrowhead shape, and the rosettes can multiply quickly, with each producing up to 20 seeds (which can remain dormant for more than a decade). The result is a lake surface covered in green, and a body of water deprived of sunlight and, therefore, aquatic life. “It sounds like a Spielberg movie the more you hear about it,” Clancy said. But there’s hope. Plants that are discovered at an early stage can be removed before going to seed. “This is one invasive species war we can win,” Pat Rector, the environmental and resource management agent with the cooperative extension of Morris County through Rutgers University, told the crowd on Friday. “The best thing is early detection; if you find it, and get rid of it early, you win. That feels really good.” Using a map of the lake, Clancy carefully went through the zones that each of 36 teams will cover, connecting dots that will cover the lake’s shoreline and grid its most vulnerable places, such as Landing, Crescent Cove, and the northeast corner around Woodport. The volunteers include Knee Deep Club members as well as members of the Lake Hopatcong Yacht Club, the Antique & Classic Boat Society, the Garden State Yacht Club, and the Homestead Beach Association (and Lake Shawnee residents have volunteered to conduct searches upstream). Between June 4 and 13, scores of paddlers known as water scouts will wear bright yellow hats and survey their specific areas, marking any water chestnuts they may find and informing lakefront home owners or passersby about the effort. “It’s very important to take this and make it a teaching opportunity,” Clancy said. “The threat is not going away, so we need all the eyes around the lake to know what the water chestnut is, and know what to look for and how to report it if they find one.” For the survey effort, the teams will carefully search their designated area and report back to Clancy. “Hopefully everyone calls and says, ‘all clear,’” he said. In the event a team discovers the water chestnut, they will mark it with a bright pink streamer, take a photo, mark its general location on land if possible, and report back. Once the surveys have been completed, the club will craft a plan to remove any plants that may be found in a way that minimizes the risk of spreading any seeds—an effort that needs to take place before the seeds become viable in August. Clancy said it was promising that so many people have turned out to be proactive in this effort. But more than anything, he wants everyone in the watershed to be able to recognize the water chestnut and be on the lookout so that any future incidence will be quickly removed. “As important as the initial survey is, it’s also important to turn this into an educational moment,” he said. By sending the water scouts out with bright yellow hats and stacks of brochures about the water chestnut, he hopes the early-June surveys will be as successful in spreading the word about the effort as they are in searching for the plant itself. “We want this knowledge to be part of the culture of the lake community.” For more information about the water chestnut, visit the Knee Deep Club’s website, kneedeepclub.org, or search for information and photos online, using the Latin name to avoid getting recipes for Chinese food (the water chestnut that comes with your takeout is a different species): Trapa natans is what you’re looking for.