Nuangola Lake taking a whack at weeds

It looks like a tricked-out combine.

But, instead of rolling on fields of oats or wheat, Dan Morgan’s machine floats on water.

Morgan, owner of Northeast Aquatic Plant Harvesting in Dushore, has been hired by the Nuangola Lake Association to remove thick plant growth they say is choking the lake and threatening to deplete oxygen levels. Morgan has been operating his weed harvester all week and has already removed at least 20 tons of plant material. He said the work will continue into next week.

Morgan has been using his machine to remove aquatic plants on lakes for three years. He said the growth in Nuangola Lake is the thickest he has ever encountered.

“We’re focusing on the worst spots to keep it under control,” he said. “There are some private areas on the lake where they couldn’t get their boats out, and we’re also focusing on the outlet to improve water flow.”

The weed harvester looks complicated but the process by which it works is simple. Three sickle bars with reciprocating knives are lowered under the water. The sickle bars cut the aquatic vegetation, similar to mowing a lawn, and the cut plants are removed from the lake via a conveyor. The conveyor stores the cut growth in a bin which is unloaded on shore when it fills.

The plants being targeted include lily pads, water shield (a smaller lily pad) and a floating mat of vegetation that Morgan said is 18 inches thick.

Charles Shea, president of the lake association, said this is the second year Morgan has been at the lake. The water is clearer since Morgan began removing plant growth last year, he said, and the work is part of a larger lake management program that includes water testing, monitoring, and the use of aeration systems.

“There’s an extensive, heavy weed carpeting that we’re trying to get under control,” Shea said.

When the vegetation dies and rots every year, it releases microbes that consume the oxygen in the water, according to Dale Bruns, dean of the College of Science and Engineering at Wilkes University, and a river ecologist. When all the oxygen is gone, the lake becomes anaerobic and can kill aquatic life.

Bruns said the removal of aquatic vegetation is a short-term solution and there are downsides and benefits.

“When you do this, you remove natural habitat, but the tradeoff is if the lake becomes anaerobic you lose the organisms in it,” he said.

The plant removal can also open the door for invasive species to take over, Bruns cautioned, because the process creates a disturbed area. Mark Carmon, spokesman for the state Department of Environmental Protection, said permits aren’t required for weed harvesting operations.

“Weed harvesting isn’t the worst or the best thing to do, but there are limited alternatives,” Bruns said. “The use of copper sulfate, for example, results in loading a heavy metal into your aquatic ecosystem. The key is to keep the nutrient loads which cause excessive weed growth out of the lake.”

Last year’s plant removal cost the association approximately $70,000, and the price of this year’s work will be about the same, Shea said.

“The water quality at the lake this year is better than anyone can remember,” Shea said. “We’ll continue this work on an annual basis to maintain the growth so it doesn’t choke off areas of the lake.”

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Lake association using harvester to remove thick plant growth from water.

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