Elodea update for Copper River Delta

The U.S. Forest Service, Copper River Watershed Project, and Alaska Department of Natural Resources have begun work on Elodea control on the Copper River Delta. Elodea sp., also known as waterweed, is an invasive aquatic plant that was first discovered in Cordova in 1982 and more recently found on the Kenai Peninsula, Anchorage, Fairbanks, and Mat-Su Valley.

In the Cordova area, Elodea can be found in Eyak Lake, Eyak River, Eyak Cannery Ponds, Wrong Way and Wooded Ponds, McKinley Lake, Martin Lake, Bering Lake and several sloughs and ponds near Alaganik Slough.

On June 29, the first herbicide treatment on the Delta was completed in the Eyak Cannery Ponds. This initial small scale treatment to two ponds and a section of slough totaled 25 acres. Application was done with two 4-gallon capacity backpack sprayers for applying liquid Sonar Genesis and a hand-held spreader for applying solid pellets of SonarOne.

The active ingredient in both formulations is fluridone, applied at 6.5 parts per billion and 9.5 part per billion, respectively. Biweekly water samples will be collected between mid-July and September to monitor fluridone concentrations in the ponds and slough. A smaller follow-up application with pellets only (SonarOne) will take place during the third week of September.

Monitoring of native vegetation, fish, macroinvertebrates, and water chemistry will continue to occur in the Eyak Cannery Ponds and other reference ponds monthly through October.

Monitoring will be used to determine the effects of Elodea on aquatics systems on the Delta, the effects of treatment on native species and Elodea, and to determine how quickly native species recover in areas where Elodea has been eradicated.


A reminder that since 2014, two species of Elodea (Elodea canadensis and Elodea nutallii) and three other aquatic plant species have been quarantined by the State of Alaska, including prohibition on the sale, transport, import, distribution, or buying of any plant or plant part.

Elodea unfortunately spreads quickly and can revegetate from just a fragment of a plant. Keep in mind “Clean.Drain.Dry” to prevent the spread of Elodea on your recreational equipment.

For more information visit http://copperriver.org/programs/

By Danielle Verna