Seal of Dane County County of Dane
Dane County Land & Water Resources Department

1st Year Results Available for Aquatic Plant Research Project in Lake Monona-Public Meeting April 2

March 27, 2009
Sue Jones, Dane County Lakes and Watersheds (224-3764)
Land & Water Resources

First Year Results Available for Aquatic Plant Research Project in Lake Monona

Turville Bay project showed effectiveness of early-season herbicide application

Public Informational Meeting Set for April 2

(Madison, WI)  People living near Turville Bay in Lake Monona, and others interested in the restoration of native aquatic plant communities in the Yahara Lakes, can now view detailed first-year research project results, at the Dane County Lakes and Watersheds website: 

Last year was the first of a five-year study to determine if either or both of the evaluated management approaches (early season application of the selective granular herbicide 2,4-D, treatment and early season deep mechanical harvesting) are viable methods to control nuisance exotic plants, especially Eurasian water milfoil (EWM), and aid in restoration of native plant communities.  Two five-acre sites in Turville Bay receive herbicide application; two five-acre sites receive mechanical harvesting, and two other five-acre sites are untreated and used as controls.  Early-season treatments target EWM early in its growth stage, before most native plants begin to grow.  Research cooperators collected data on plant frequency, water quality and water clarity, before and after the chemical and physical treatments on Lake Monona’s Turville Bay in April and May 2008.

A public informational meeting to discuss the continuation of this study will be held from 6 – 8 p.m., Thursday April 2, 2009 at the Waubesa-Kegonsa Room in the Exhibition Hall at the Alliant Energy Center, 1919 Alliant Energy Center Way in Madison. 

“It’s promising that these treatments can favor native aquatic plant communities over weedy invasive plants,” said Dane County Executive Kathleen Falk.

Researchers found a decrease in the frequency of occurrence of Eurasian water milfoil in the chemically-treated plot and a statistically significant treatment effect.  High water levels, cold temperatures and high winds in 2008 complicated mechanical harvesting study methods, and may have obscured the effect of harvesting.  The cooperating researchers hope to be able to evaluate treatment methods during more typical water, wind and temperatures during subsequent study years.

“For those of us who swim, boat, and enjoy the lakes, this gives us hope that we can reduce the problems caused by Eurasian water milfoil,” said Brett Hulsey, chair of the Dane County Lakes and Watershed Commission.

Eurasian water milfoil begins growing early in the year, and creates a dense growth canopy which shades out native plant species.  Dane County waters have supported populations of this exotic invasive aquatic plant since at least the 1960’s. Eurasian water milfoil is found throughout the Yahara Chain of Lakes (Mendota, Monona, Waubesa, Kegonsa and Wingra), and the impacts of this plant have been far-reaching. EWM has been associated with a decrease in biodiversity in the Yahara system, decreased aesthetic value, impeded recreational use in shallow areas, and impacts to the Yahara fishery.

The research project’s herbicide application for 2009 will most likely occur in early to mid April when EWM growth and water temperatures are suitable for treatment.

The research is being supported by a Department of Natural Resources Aquatic Invasive Species grant and by DNR staff time, with matching funds and labor provided by the Dane County Department of Land and Water Resources and the U.S. Army Corps of Engineers.