Case Study: Midwest Winter Aquatic Growth

Pewaukee Lake is the largest of the ninety-one lakes located in Waukesha County, Wisconsin. It is a premier lake for Musky, Walleye, Northern Pike, and Largemouth bass. It supports a diverse plant community that is dominated by Eurasian watermilfoil. The Lake Pewaukee Sanitary District is in charge of lake management and its program consists of many pieces of aquatic weed harvesting equipment. It is apparent that an autumn harvest cuts back the milfoil, which is flourishing under the ice, to allow native plants an opportunity to grow.

Pewaukee Lake is about 5 miles long and 1 mile wide and covers 2437 acres. It has a maximum depth of 45 feet and is known for its inland sailing races and abundance of fish. It is a premier lake for Musky, Walleye, Northern Pike, and Largemouth Bass.

Pewaukee Lake’s aquatic plants have been monitored since 1988 in an effort to aid in lake management. The lake has a diverse plant community that is dominated by Eurasian watermilfoil but has many native species including Pondweed, Coontail, and Muskgrass.

300 feet out on January 9th, 2013 the Eurasian milfoil is quite healthy and seems to be flourishing under the surface of the frozen lake. This portion of the lake remains untouched by the aquatic weed harvester and the District does not apply aquatic herbicides.

The effective management of the lake has kept the milfoil in check and allowed native species to survive An autumn harvest helps to cut back the dominant milfoil and provides the native plants an opportunity to grow. 75 feet out in 4.5—5 feet of water the crews were able to perform a “deep cut” cutting near the lake bottom. As you can see, there is very little milfoil growth. During the 2011 harvesting program, 11,412 cubic yards of plant material was removed from Pewaukee Lake.