Goals. The Friends of Lake Wingra (FOLW) and the community have identified four goals for the future: Clean, clear water; restored springflow; abundant native plants and animals; and promoting stewardship and enjoyment. All our educational efforts should seek to clarify and expand on these four goals.
Watershed. The health of the lake is dependent on the health of the watershed. The two biggest threats to the watershed are disruption of the natural cycles of water (lack of infiltration) and nutrients (leaves, fertilizer, erosion).
A consistent effort. Restoration of the watershed will require progressive healing, in a multitude of small places over many decades. It will require a community-wide effort, involving the City, business, schools, and private citizens. What you do at home makes a big difference. Citizens can keep leaves out of the street (and recycle them), redirect down spouts onto their gardens, and build rain gardens wherever they can.
Why restore the health of the lake and watershed? The benefits will be many, including improved recreation, beauty, lifestyle, community health, and property values. Improved free services from the environment mean lower taxes. Less flooding.
Change. Both the lake and the watershed have been profoundly changed by settlement. The watershed has been paved, with reduction in infiltration, and introduction of pollutants. The lake itself has been changed by increase in stormwater, dredging, a dam, and introduction of exotic species. The balance of species has changed dramatically.
Phosphorus. "In Lake Wingra, algae growth depends on phosphorus. One pound of phosphorus entering the lake can produce up to 500 pounds of algae! Common sources of phosphorus include fertilizers, eroded topsoil, decaying leaves, and goose and pet feces. Excessive phosphorus encourages blue-green algae that can be toxic to fish, pets and people."
Groundwater is essential. Groundwater--from seepage or springs--contributes 35% of the lake's water. It used to be much more--only about 8 of 30 former springs remain, and their flow is reduced. Groundwater is vital because it is extremely clean, and its cool temperature helps keep the lake cool, with more dissolved O2.
Diversity. We can't expect to eliminate all aquatic plants--but we should strive for diversity, without dominance of Eurasian water-milfoil. We should manage the lake for the overall health of the ecosystem--not just for human convenience.
Carp. The common carp is a messy bottom-feeder that uproots aquatic plants, churns up sediment, clouds the water and degrades the health of the entire lake. Pilot projects (exclusion area, and netting in the whole lake) demonstrated that if carp are greatly reduced in the lake, water quality improves. It is not possible to eliminate all carp. Netting of carp several years ago has greatly improved water clarity--which in turn has caused changes in aquatic plant growth. These changes demonstrate that the lake is a very complex system--not everything is predictable. Time for a little humility.
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Source: Boiled down from the classic booklet on Lake Wingra