Shoreline Concerns
Spraying the lake for Eurasian watermilfoil
Integrated pest management practices in Washington encourages lakeshore residents to consider various methods of invasive weed control. Hand removal, mechanical removal and biological control using grass carp or weevils were all considered for their effectiveness at reducing the invasive milfoil in American Lake. Herbicides were the final choice of action. But they must be applied carefully and with the least environmental and disruptive damage.
Why do we use ProcelleCOR herbicide to kill invasive milfoil? Why don't we just rake it or pull it out by hand?
Eurasion watermilfoil grows rapidly in the summer, many inches per day, and it will lie in mats on the surface. The leaves are in whorls around the red stem. At each node of the stem roots stick out and are ready to grow if they touch the bottom of the lake. If we rake it out, the nodes break and spread along the shore taking root and growing. They are carried by wind and waves all over the shoreline. To hand remove it, we considered using diver assisted suction harvest, but the cost was prohibitive for a lake with an infestation as widespread as we have in American Lake. It was also not as effective at keeping plants from growing the next year.
2-4-D is the most widely used herbicide in north America to control large populations of invasive water milfoil. However, it also kills native and other preferred plants. It requires a period of no use of the water. ProcelleCOR has no use restrictions and it only kills milfoil plants. It is also less expensive. After learning of these advantages at public meetings. the lakeshore residents chose ProceliCOR applications.
Have there been any problems with ProcelleCOR?
Lake George in New York state had some complaints and concerns about ProcelleCOR. Read about it here.
Why is ProcelleCOR applied in the summer, not spring?
The water temperature must be at least 60 degrees for the chemical to work. The product is systemic which means the plant needs to take it up from its leaves and let it be carried and absorbed by all parts of the plant in order to kill the roots. If it is applied while the plant is still rapidly growing in the spring, it may be too small to absorb enough to kill it.
Another reason to wait is that Eurasian watermilfoil is too small to detect in the spring. It needs to grow large enough to locate the patches, so the underwater surveys must wait until June.
Can the LMD hire more than one applicator to manage the lake?
Yes, whenever the LMD adds a work project, they will advertise a Request For Proposal (RFP) for any qualified applicator to apply and bid on the project. The applicator must have all current licenses for any pesticide that will be applied. The chemicals or treatment followed must comply with all Dept. of Ecology laws concerning fish habitat, percentage of shoreline treated, species being controlled, and other legal environmental factors.
Generally, one applicator is chosen for one work project, however, a few LMDs have multiple applicators that divide up one work project.
Aquatechnex won the contract for managing invasive aquatic plants. They created our Invasive Aquatic Vegetation Management Plan (IAVMP). Currently it manages the Lake for Eurasian watermilfoil. They can also manage other invasive weeds. So, each year when the contract is re-submitted to the City for renewal, Aquatechnex also includes the price for treating a variety of other invasive plants, such as curly leaf pondweed. Managing all invasive aquatic plants is part of the IAVMP. However, we don't pay for anything other than milfoil treatment. The reason is discussed below.
How much does it cost to treat the lake?
Currently we collect about $23,600 from shoreline assessment. The cost of treatment for Eurasian watermilfoil alone is about $80,000 for the entire lake. JBLM pays for 45% of the bill since they own that amount of the shoreline. Shoreline owners were then responsible for $44,000. Since our assessment is too low to cover that cost, the LMD applied for a grant from Dept. of Ecology for $75,000. This grant made up the difference of what we owed. The LMD held over the rest of it for 2026 treatment. But it will still fall short this year.