Weed Control Planned for Mineral Lake 2021

Treatment Planned for Mineral Lake Summer 2021

The newest resident in the picturesque community of Mineral, WA is an unwelcome one. Eurasian watermilfoil, a Class B noxious weed in Lewis County, has been taking up residence at various locations around Mineral Lake. If left unchecked, this tenacious water weed has the ability to impede access to the lake, significantly reduce fishing opportunities, and have an overall negative impact on the recreational value of this beautiful Lewis County lake.

Mineral Lake, WA

Eurasian watermilfoil is a perennial aquatic weed, native to Europe and Asia. Once a popular aquarium plant, it is likely that dumping of home aquariums has led to the introduction of this noxious weed in Washington’s natural areas. Easily propagating from small plant fragments, Eurasian watermilfoil spreads easily by hitchhiking on boats, boat trailers, and other recreational gear.

An infestation of Eurasian watermilfoil can completely change the characteristics of the infested water body, leading to increased sedimentation, depleted oxygen levels, reduced water flow, critical changes to fish habitat, and an overall reduction in recreational value of the affected water body. An entire lake can become infested within two years of the initial introduction.

Lewis County Noxious Weed Control staff observed Eurasian watermilfoil growing near and around the WDFW boat launch in the fall of 2020. Subsequent surveys conducted by Washington Department of Ecology confirmed small populations of milfoil occurring around much of the perimeter of Mineral Lake.

Eurasian watermilfoil


No stranger to economic hardships, the community of Mineral has found success as a tourist destination, known for the premier trout fishery. Mineral Lake touts itself as the “Home of the 10-lb Trout” and hosts recreational fishermen throughout the open fishing season. Washington State Department of Fish & Game (WDFW) routinely plants rainbow trout, brown trout, and a many large brood stock to attract the sport anglers. The lake also supports native cutthroat trout, crawfish, and largemouth bass. Due to its convenient location, close to both Mount Rainier National Park and Gifford Pinchot National Forest, Mineral Lake is gaining popularity amongst hikers, kayakers, paddle boarders, and campers throughout the spring, summer, and fall seasons.

In an effort to minimize damage to the lake’s wildlife habitat value, recreational value, and economic value, the Lewis County Noxious Weed Control Board plans to treat the Eurasian watermilfoil In Mineral Lake with an approved aquatic formulated selective herbicide in the first half of July 2021, and possibly, a second treatment in August. The selective herbicide used will target the photosynthetic process of the Eurasian watermilfoil. Unable to complete the cycle of photosynthesis, the plants should begin to die, sinking to the bottom of the lake where they will quickly decompose. It is expected that native aquatic plants will be impacted, however this impact should be minimal. Due to the nature of Mineral Lake, the fact that this population is still new, and the level of infestation is still considered manageable, it is the goal of the Lewis County Noxious Weed Control Board to totally eradicate this weed from the lake.

Lewis County Noxious Weed Control will start conducting widespread education and outreach to the community of Mineral, the businesses, landowners, and the lake’s users in April 2021 in an effort to make sure that all concerns are addressed and all relevant information is made accessible.

To find out more about Eurasian watermilfoil, visit Washington State Noxious Weed Control Board https://www.nwcb.wa.gov/weeds/eurasian-watermilfoil

To view the Notice and Information for Noxious Weed Control click here.

If you have any questions or concerns about the Lewis County Noxious Weed Control Board’s plans for herbicidal control of Eurasian watermilfoil in Mineral Lake, please contact our office at # (360) 740-1218, or email us at weeds@lewiscountywa.gov

Posted: April 02, 2021