Upper Lakes Aeration and Mechanical Fish Removal

Two hypolimnetic aerators were installed on Lakes Louisa and Marie in 1985-1986. They pumped oxygen into the hypolimnion (bottom-water) of both lakes. By doing so, the amount of phosphorous released from bottom sediments is greatly reduced, thereby increase the water quality in the lake. The aerators have been discontinued due to high operation costs. Check out the replacements for the aerators to see the projects that took it's place.


In addition, mechanical removal of rough fish (carp, bullhead, etc.) was performed on Betsy, Scott, Union, Louisa, and Marie during the fall of 1984 and the spring and fall of 1985-1988. Being bottom feeders, rough fish mix large amounts of nutrients into the water from the bottom sediments, as well as disrupt the food chain for other animals, causing a detrimental effect on water quality. The estimated cost of this project was $285,000, and it removes an estimated 1,800 pounds of phosphorus annually.
View Watkins Wetland Isolation Project