Cascade Water Alliance, owner of Lake Tapps, last year began a multi-year program to address milfoil growth by treating 400 acres of the lake. A recent survey revealed the milfoil infestation on the lake has been greatly reduced. The second year of treatment will begin in August.

“The 2011 treatment plan calls for treatments on Monday, Aug. 15 and Tuesday, Sept. 6 with an option to do an additional small quantity should we notice other areas that we missed from a boat survey to be conducted in mid-August,” said Jon Shimada, Cascade’s capital projects director. “If other areas are added, there will be a third treatment date in late September.”

Cascade awarded the 2011 contract for milfoil treatment to Aquatechnex, the same contractor who conducted the 2010 treatments. Aquatechnex will perform herbicide treatment to approximately 100 acres of the lake this year.

Eurasian Water milfoil is a non-native, invasive aquatic plant that spreads rapidly, crowds out native plants and forms dense surface mats in Lake Tapps.

The treatment will consist of applications of Sonar PR (Fluridone) as used last year, with the addition of Renovate OTF (Triclopyr.) The Renovate label states “there are no restrictions on use of water in the treatment area for recreational purposes, including swimming and fishing;” however to prevent eye irritation, the State Department of Ecology imposes a 12 hour restriction on swimming after treatment.

For limitations on uses and other information about Renovate, please see www.sepro.com and www.ecy.wa.gov.

The State Department of Ecology requires a 10-day notice period per treatment application. Homeowners in affected areas will be notified at their property that treatment will be done.