Pewaukee Lake was formed in 1838 when a dam was constructed along the Pewaukee River and the wetland was flooded. It combined with Snake Lake to form the 2,500 acre Pewaukee Lake.
For 40 years – 1945 to 1985 – the sanitary district used herbicides, including 2-4-D for 17 years, in an attempt to control the weeds. Since 1947, the district also harvested weeds from the lake and would pick up the weeds that washed on the shoreline.
In 1985, the use of chemical herbicides was discontinued on the lake and an expanded weed harvesting program began. The harvesting and removal of the plant material reduced nutrients available for the regrowth of the invasive watermilfoil and allowed for a better diversity of native aquatic plants.
The Lake Pewaukee Sanitary District understands the value the aquatic plants have on the stability of the lake bottom as well as value the plants have on the aquatic life thriving in the lake. They also understand the importance of keeping the aquatic plant levels down to allow human recreation.
The District starts its harvesting program earlier than any other lake in Wisconsin and runs the program longer than any other lake in Wisconsin in an effort to knock back the invasive species and promote the native species. The challenge becomes what the budget and time allows and the cost benefit of what is being accomplished. The District has been slowly increasing the equipment and labor force in an effort to continuously improve the harvesting operations. Small budget increases are helping increase manpower and more importantly set up the 2nd shift program for years that the cycle provides a peak aquatic plant growth season.