The Problems

Lake Washington is the state’s largest lake, bordering on many cities and communities and containing vital salmon runs and many other important aquatic species. Because of the major loopholes in the state permit concerning the use of aquatic pesticides, any individual on Lake Washington has the ability to apply to put herbicides into the lake along their property without consulting with their neighbors or any other lake users.

At the most basic level, there are many questions about the long-term impacts of these herbicides on lake ecosystems, including impacts to the hundreds of thousands of people that live around or recreate on Lake Washington. Lake Washington is also the migration path for several salmon runs, including listed endangered Chinook runs. Juvenile Chinook salmon migrating out of Lake Washington during the summer are put at risk by any herbicide applications to the lake, and we should weigh on the side of caution when it comes to protecting this endangered species.

The reality of a lake as large as Lake Washington is that invasive weeds like milfoil are not going to be eradicated. The lake is too large and there are too many boats going in and out of it to hope to eradicate already-established invasive plants like milfoil within the lake. If weed eradication is not a possibility, any attempt at controlling the weeds is just an annual knock-back. This means that aquatic herbicides basically are just a type of  “chemical mowing” – one that might reduce the quantity of vegetation in an area for that year, but one that puts at risk our health and the health of our lake. 

In addition, the state permit is not written for lakes as large as Lake Washington, where dozens of individual herbicide applications may occur. In 2004, upwards of 70 individual and uncoordinated herbicide applications happened in Lake Washington alone. People living directly adjacent to a property that chooses to use aquatic herbicides may only have 10 days prior notice of a herbicide use, well after any public comment period regarding the granting of the permit for the herbicide application has expired.

As the Department of Ecology website does not include actual permit applications or the exact location of applications that are not lake-wide, it seems impossible for a citizen to determine what applications may be occurring in their community. This is particularly true for Lake Washington, where thousands of individual properties line the banks. This is another reason why this permit and Ecology’s implementation of it are not appropriate for Lake Washington. 

The Solutions

Lake Washington needs a separate permit regarding control of aquatic vegetation — one that requires available non-toxic alternatives to be utilized, one that takes into account an increased need for community dialogue before permits are granted, and one that includes more notification of planned herbicide uses. 

Our state and local governments should also initiate a lake-wide group — including the many stakeholders and communities around the lake — that can work to address invasive vegetation problems and find healthier, coordinated, long-term management options for Lake Washington.