Over the course of several weeks this summer the Village of Pewaukee and the Town of Delafield, prompted by initial action by the City of Pewaukee, passed a notification ordinance regarding chemical treatment for invasive lake weeds in Pewaukee Lake. The ordinance was initially prompted mainly by one City of Pewaukee resident. The other two municipalities passed similar measures, they claim, for reasons of regulatory consistency.

Despite some language in the ordinance implying the contrary, it has been determined a number of times that the State of Wisconsin has jurisdiction over the surface waters in the state, and that riparians (lake property owners) have rights to access and manage the near-shore area subject to state code. As a result, the ordinances really only affect property owners, not chemical application firms (generally the permit holders) who already operate legally under the direct supervision of the Wisconsin DNR. Further, the ordinance only adds the requirement for significant additional notification of application beyond what is already required by the DNR for everywhere else in the state. The municipalities have no jurisdiction to regulate the actual application of lake weed treatment products by regulated permit holders. The City of Pewaukee ordinance includes a fine for property owners should their notification procedures not be followed or should some of their notification signs be prematurely removed from the treated property. In brief, the ordinance requires notification by individual lake weed treating property owners to owners of all neighboring properties within 500 feet of the treated property. (It is not clear if posting treatment notification signs is considered sufficient notification to satisfy the requirements.) In addition, signage indicating lake weed treatment must be posted on the property lines of treated properties near the shoreline, and facing neighboring properties. These signs must be posted seven days before treatment, include the treatment date and an alternate date, and remain in place for either seven or fourteen days after treatment depending on interpretation of the ordinance.

The weed treatment product 2,4-D used to treat the runaway invasive lake weeds in Pewaukee Lake has undergone rigorous testing for both effectiveness and for potential negative effects on human health. It has been in use since 1946 and when properly applied is not harmful to humans and dissipates quickly from the environment (within 18-72 hours). The Industry Task Force II on 2,4-D says this on it’s website:

2,4-D is one of the most widely used herbicides throughout the world. It effectively controls unwanted and invasive weeds across agricultural fields, lawns, public parks, lakes and more. Introduced in 1946, 2,4-D is among the most rigorously researched and regulated molecules of all time.

Very few substances have been subjected to the extensive examination and review that 2,4-D has withstood, and as a result, more is known about 2,4-D than almost any other chemical on the planet. Just as it has for more than 60 years, 2,4-D continues to be one of the most important herbicides for homeowners, land managers and farmers across the globe.

If you treat your lawn for weeds like dandelions you are most likely using 2, 4-D. Because of its record on effectiveness and safety, the DNR does not require the additional signage and notification postings specified in the local municipality ordinances. Here are a few facts to bear in mind:

• The new notification ordinances have no bearing on the actual DNR regulated and on-site supervised chemical treatment of invasive lake weeds since the local municipalities have no jurisdiction over lake weed treatment.
• While the ordinances call for the permit holder (usually the treatment company) to comply with the additional notification requirements, the weed treating property owners are held liable for failure to comply.
• When properly applied, the treatment product 2,4-D is safe and effective and does not present a danger to humans or pets. It can be used to selectively remove some invasive weed species without threatening native lake plants unlike mechanical weed harvestors.
• 2,4-D is the same chemical used on hundreds of lakeside lawns to treat for lawn weeds each year.

Chemical lake weed treatment is an important component of the overall invasive lake weed control and eradication plan. Using only mechanical harvesting equipment and labor to manage invasive lake weeds, some of which can grow six inches a week, is an exercise in futility. In fact, floating remnants from machine cut weeds can quickly root, sink to the lake bed and start a new invasive weed infestation. Failure to stem the expansion of invasive weeds and to reduce their impact on the lake environment significantly reduces our property values and our ability to enjoy the lakeshore. Our recommendation—to treat with 2,4-D—is considered “effective, reliable, species selective, cost-efficient, and easy to use” according to the scientists who wrote Aquatic Plant Management, Best Management Practices.

At this writing the PLIA has not been made aware of any ordinances requiring the same notification procedures for using the same products to treat lawn weeds along the lakeshore and in the lake watershed.