LWTF MYSTERIES SOLVED:

The Case of the Mysterious Bubbles

There are four layer aeration systems or '“aerators” in Lake Waramaug. The first two were installed In 1989, suspended in deep water along the Route 45 in Washington Bay. In 2015, the other two aerators were installed near the tip of Arrow Point.

While at first glance, the aerators appear to bubble oxygen into the Lake, their actual function is to act like multi-level water mixers. These small school bus sized structures fabricated from fiberglass are submerged in the water column. They take warmer, oxygen filled water from closer to the surface and mix it with colder, oxygen poor water from closer to the bottom of the lake. The goal of this is to keep the middle layer of the lake oxygenated, and to keep the anoxic or oxygen-poor layer as far down towards the bottom of the lake as possible. This method of managing the middle layer of the lake is more efficient and cost effective than trying to oxygenate the whole bottom area of the lake.

Essentially, the compressed air pumped to the aerators is not the main way water is oxygenated in the lake. Instead, the compressed air allows the aerators to move and mix water from different layers of the lake to modify oxygen levels in the middle layer of the lake.

Each of these systems benefits the Lake by keeping nutrient rich, anoxic water at the bottom of the Lake in the summer, and by creating large areas of cold, well-oxygenated water habitat needed by cold water fish and zooplankton, the native natural predator of cyanobacteria. The Task Force data supports that keeping these aerators functioning is absolutely necessary in keeping the Lake clean clear and swimmable for years to come.