Eradication of the invasive aquatic plant elodea from Crescent Lake in the Kenai Mountains has been successful so far, but project managers say more funding is needed to complete the project.
Jen Chauvet, coordinator of the Kenai Peninsula Cooperative Invasive Species Management Area, gave an update to the Kenai Peninsula Borough Assembly on April 8. The borough has previously contributed funding to elodea eradication from the Kenai Peninsula.
Chauvet said elodea is the first and only aquatic invasive plant known to be present in Alaska, but this one weed causes a lot of trouble. It reproduces easily, with even tiny fragments being spread by boats, float planes, even ducks.
“Those fragments root to form those dense mats of vegetation, which essentially crowds out all native vegetation. It obstructs water flow, and our main concern in Alaska with it is that it devastates fish habitat,” Chauvet said.
Elodea was discovered on the Kenai Peninsula in 2012. The KP-CISMA was formed in 2013 as a partnership between federal and state agencies, tribal entities, nonprofits and local governments. Later that year, eradication treatment began on six peninsula lakes.
“By 2022, all known infestations of elodea on the peninsula had been eradicated, which was really something incredible,” Chauvet said.
But in the fall of 2023, the Forest Service documented elodea in Crescent Lake, between Cooper Landing and Moose Pass. Not only is Crescent Lake popular for recreation, with a risk of spreading elodea from float plane and small boat traffic. It also feeds Quartz Creek, which drains into Kenai Lake, which feeds the Kenai River.
“And the impacts of this species potentially spreading downstream could, as Jen described earlier, negatively impact aquatic habitat, with cascading consequences on fisheries, subsistence users, local economies and livelihoods, which all rely on salmon and the health of that watershed,” said Peter Frank, with the Chugach National Forest.
KP-CISMA mobilized again to develop a plan to treat Crescent Lake. In 2024, the team conducted field work and designed a treatment plan. The group secured funding from the Alaska Sustainable Salmon Fund in 2025 and started treatment that summer.
It’s a big lake with varying depths, about 6 miles long, covering nearly 4,000 acres. Too big to treat with herbicides all at once. The team is spot treating infestation areas across three zones and the outlet stream. The herbicides, when properly applied, are safe for fish, wildlife and humans and don’t negatively affect water quality. But according to Cody Jacobson, with the Alaska Department of Natural Resources, they can be expensive to use.
“All of this product had to be flown in by float plane, which certainly increases the cost and the application techniques of it. You're looking at roughly about 6,000 pounds of herbicide pellets that are then blown or spread via electric spreaders throughout the treatment zones,” Jacobson said.
Frank, with the Forest Service, said treatment last year went well, with monitoring showing high efficiency of the herbicides in the areas treated and minimal impacts to other species in the lake. Treatment and monitoring is to continue this summer and next. However, Chauvet said the current funding won’t be enough to finish year three of the project. KP-CISMA is seeking additional grants to finish the work.
“We have this really compelling story. Funders see the value of investing in this project to safeguard, you know, the iconic Kenai River, the salmon it supports and that we all value (and) depend on,” Chauvet said.
More information on KP-CISMA, elodea and the other invasives it monitors can be found at kenaiinvasives.org.
