During the winter of 2008-2009 there was a massive fish kill on the Big Eau Pleine reservoir in central Wisconsin that killed an estimated 75% of the fish population. This is not the first time; since 1937 when the reservoir was built there have been fish kills of varying severity every 3 to 4 years on average.
The causes tend to be the same and ultimately a lack of oxygen kills the fish. The causes of the low oxygen are: excess nutrients (especially phosphorus according to the experts) and low water levels. Under the winter ice there is no wave action to re-aerate the water and no sunlight for plants to grow under the water and produce oxygen (photosynthesis).
The consensus of opinion is that it will take a very long time (decades) before the excess nutrient/pollution problem can be resolved. There is a solution that BEPCO is calling the “60% Solution” that could be implemented much sooner. There is strong data indicating that having the reservoir 60% full on December 1 will dramatically reduce the chances of fish kills during winter on the Big Eau Pleine.
BEPCO has raised over $60,000 to replace the 30 year old aerator, but in order for the aerator to work effectively, the aerator needs to have water over the lines, so the maximum drawdown level should not exceed 20% full.
Over the first few months of 2011, WVIC will be receiving public comments on their operations practices as part of their license review process. BEPCO is proposing to add two simple guidelines on winter operations on the Big Eau Pleine:
1) 60% full (6.5 feet down) at freeze up or December 1
2) 20% maximum drawdown (16.5 feet down) to allow for effective aerator operations
In the past 41 years, there has never been a fish kill when the Big Eau Pleine water levels have been managed inside of these guidelines. Now is the time to add these guidelines to WVIC’s license for their winter operations plan for the Big Eau Pleine.
The Big Eau Pleine reservoir was built by WVIC to store water during wet times of the year in order to supplement the Wisconsin River flow during dry times of the year. This leveling of the water flow allows the power companies and paper mills that own WVIC to maximize hydropower generation. The supplemental flow during dry periods also serves to protect the fish and ecosystem of the Wisconsin River by maintaining a minimum required flow to dilute the effluents of industrial and community wastewater treatment plants that discharge into the Wisconsin River. Read more with a one page summary of the fish kill graph.
BEPCO has shown the 60% Solution can be implemented without risk to maintaining the minimum required Wisconsin River flow. These guidelines could have been met even during the drought of 2008, read more about how to implement the 60% solution. For the good of the environment, the fishery and the people of central Wisconsin, we need to stop the fish kills!
Preserve, Protect and improve the big eau pleine reservoir
Big Eau Pleine Citizens Organization