Thursday, November 3rd, 2011
Report on lake fixes released
By Nancy Allen
GRAND LAKE - A plan of short- and long-term strategies to fight toxic algae blooms in Grand Lake has been released.
Battelle Institute of Columbus, a nonprofit research and development firm, created the plan after sifting through proposals from 75 vendors. The report was presented to the Lake Restoration Commission (LRC) during a recent meeting at Wright State University-Lake Campus.
The $49,500 report paid for by the LRC and the state says the best short-term recommendation is another alum treatment in the lake next year. The first lakewide alum application was done in the summer at a cost of $3.4 million. Funding has not yet been secured for another treatment.
The report says alum treatments should be repeated periodically. Aluminum sulfate (alum) deactivates phosphorous, the algae's main food source.
LRC representative Julie Miller said the report is only the beginning of further testing of products. The LRC plans to release information as early as next week on a pilot project to test different types of aeration in lake channels.
"We looked at it (study) as a screening tool, and now testing will begin," she said. "We have further work to do to define costs for projects both in the lake and out in the watershed."
Multiple products and vendors show promise, Miller said. Six might work in the lake and eight to 10 might help decrease phosphorous in the watershed.
The report says more than one technique may be used at once to reduce lake phosphorous levels, but for them to work, external sources should be controlled. Any market-driven use or removal of phosphorous, such as dredging the lake sediment, should be encouraged. Best management practices on farms and human sources of phosphorous such as septics also are needed to reduce external loading.
The report speaks to a plan by Wisconsin-based company Amiran Technologies, which wants to build plants that turn manure into fertilizer and lake sediment into potting soil. The report says while this would obviously help with lake phosphorous loading, the company's plan still has many facets that are not entirely clear or proven certain to succeed.
The report says studies show that removing 75 percent of rough fish, such as carp, can flip toxic algae species to instead be dominated by beneficial aquatic plants. The state performed its first phase of rough fish removal this year, taking out 13.5 tons, and plans more next year, said Brian Miller, manager at Grand Lake St. Marys State Park.
Some algaecides may be effective in the lake, but would provide only short-term results and may need to be repeated multiple times during a season, the report says. Using them also can release algae toxins into the water column.
The report looked at different types of aeration that would work best in open bay type areas of the lake and in channels. The report recommended horizontal aeration, such as Airy Gators, for open bay areas. For closed channels, a system that pumps water from the lake body into the back of the channel to flush it, was recommended. The report suggested further testing be done at open and closed channel areas to determine the appropriate number of aerators to use.
Vendor proposals were analyzed by the type of merit, their form and purpose, which includes controlling phosphorous loading, promising proposals from Ag Solutions, biomanipulation and algaecides.
A copy of the Battelle report is available on the Lake Improvement Association's website at www.lakeimprovement.com.