Cottage Q&A
QUESTIONI have a cottage on Lac Bataille, in Quebec, where we are encountering problems with water quality. An environmental study found, among other things, that the lake was over-fertilized and the water was oxygen-deficient. Although the study identified a number of areas for immediate attention, including deforestation and runoff from roads, one of its conclusions was that the condition was irreversible. The best we could hope to do was to "put the brakes on" and slow the process. Since reading the report I have become aware of success stories where bodies of water with similar symptoms have been treated and the water quality has been revitalized. Would you have any information on this subject?
ANSWER
A number of technologies have been developed for revitalizing lakes such as yours, with too many nutrients and too little oxygen. The Lake Lung, developed by Andy Gemza of Ontario's Ministry of the Environment (MOE), pumps extra oxygen into the lake's lower levels, and has been used with some success on several southern Ontario lakes. Ocean Arks International, of Burlington, Vermont, manufactures the Lake Restorer, a floating platform that supports a small-scale, but intensely active, ecosystem consisting of a variety of plants along with their associated aquatic organisms and micro-organisms. The restorer stimulates biological activity in the water around it, introducing oxygen and beneficial organisms, stripping excess nutrients, and digesting pollutants - in other words, accelerating the natural processes by which a lake normally maintains its own health. The technology is expensive (a restorer starts at $20,000 U.S.) because every solution is custom designed, using plants and organisms from the surrounding wetlands. Dozens of local factors, such as sediment depth and water temperature, must also be taken into account. To introduce one of these systems in Ontario, you'd need the blessing of the MOE. While no specific permits are required for a platform, you would be liable for any environmental damage it caused.
Would such a technology fix be appropriate for your lake? "It would have to be pretty bad to be ?irreversible,'" says aquatic scientist Neil Hutchinson of Gartner Lee, an environmental consulting firm with an office in Bracebridge, Ont., that has been involved in lake remediation projects in many parts of Canada. "But there's no point getting into the expensive technology until you have eliminated the original sources of the problem." It's not clear from your question whether your lake users have "put on the brakes." But you've taken the first step - an environmental assessment to establish the nature of the problem, pinpoint the causes, and suggest options for a remedy. If hard numbers and a battery of tests are needed, the assessment can be expensive - but an elaborate study often isn't necessary, suggests Hutchinson. Sometimes, an expert can walk around the lake, look at the maps, and identify the most likely problem areas, such as hard-surfaced roads, lawns mowed down to the shoreline, and overloaded septic systems. (Cottagers and associations can also take on the assessment process themselves. A program called the Watershed Report Card leads participants through the process of assessment, monitoring, and options for remedial action. For more information, call 519-832-6397 or go to www.watershedreportcard.org.)
An over-fertilized, oxygen-depleted lake like yours doesn't necessarily require a technical fix. Hutchinson points to Lake Erie, once a dying lake and considered by many a lost cause, as an important success story. It was helped by federal legislation mandating phosphate reduction in detergents and phosphorus removal in sewage plants. "All we did to Lake Erie was turn off the taps - shut off the major sources of nutrient loading," he says. "And Lake Erie has responded beautifully."
* Published in the June 2002 issue of Cottage Life
