Aquatic Plant (Weed) Harvesting Projects
A Brief History
Aquatic plant harvesting has been a very important activity for the District and has consumed a significant amount of time and resources throughout its history. Within a few months of the inception of the District, a petition from Melissa-Sallie residents called for establishment of a project to remove lake weeds. It was conventional wisdom among limnologists of the time that the most practical way of reducing nutrient levels in lakes was to remove plant material (which contains large quantities of nutrients). Indeed, the 1967 Overall Plan prominently featured mechanical removal of excess aquatic plants as a means to address lake "eutrophication". In 1968 the District established the first of three projects (Watershed District Project 1) aimed at removing aquatic plant material from Sallie and Melissa. Originally funded in large part by grant money and donations from teh City, County and lake associations, Project 1 operated off and on until 1978. It was succeeded by Project 1a in 1978, and 1b in 1985; successor projects relied heavily upon donations from the District general fund, as well as direct assessment to affected lakeshore property owners.
After several years of systematic evaluation which received national attention from limnologists, research by Dr. Joe Neel (UND) concluded that significant nutrient reduction could not be brought about by harvesting. In the early 1970's the District shifted its harvesting emphasis towards reducing aquatic plants in order to enhance boating and swimming. A Detroit harvesting project 1C was established in 1990, with the added control of the exotic plant, Flowering Rush, to its project purpose.
The MN DNR has been widely discouraging mechanical harvesting in lakes for the last several years. Beginning in 2003, the District began experimenting with herbicides to control Flowering Rush under the auspices of the Harvesting Projects. In 2013, after protracted negotiations with the MN DNR, and elaborate research efforts by national experts and the Army Corps of Engineers, the District began aggressive control measures using the herbicide Diquat. Control efforts have been widely seen as successful and the research was concluded in 2017.
In 2016 and 2017, the District began to chemically treat Curlyleafed pondweed on Lakes Detroit, Curfman, Sallie and Melissa. With the success of these treatment, the District felt confident in selling the last mechanical harvester.