Consultant says Gardner Lake in good shape
Salem - Gardner Lake's water quality and plant life is in good shape, according to a presentation given to the Gardner Lake Authority last month by Robert Kortmann, president of the Coventry-based Ecosystem Consulting Service.
The presentation also provided an opportunity for commissioners to ask an expert about water sampling as well as some things they observed at the lake, such as a temporary population of red-colored algae and unusually warm water.
Kortmann said the water quality at Gardner Lake has been good, and focused his discussion on rooted aquatic plants, providing detailed information on some of the common invasive species as well as the less problematic ones. The information was gathered during a survey that was completed in July, he said.
In 2007, there was concern with the abundant fanwort growth at Gardner Lake competing with native vegetation and changing the lake's habitat.
Fanwort is a type of plant with fan-like, floating underwater leaves, and some people are concerned with it posing a "recreation nuisance" to swimmers, said Kortmann.
There were more fanwort sightings in this year's study than in previous years, said Kortmann, but he told the commission members that he was not very concerned about the species. Rooted fanwort was limited to two locations, he explained, and the fragments of fanwort seen on the lake's surface may have been stirred up by heavy boat traffic during the weekend before the study.
The rooted fanwort plants were surrounded by native species, indicating that the fanwort is not out-competing them. The non-native plant was also found in water deeper than 6 feet, where it doesn't pose much of a hazard to swimmers.
Kortmann said the practice of drawing down the lake by 3 or 4 feet in the winter has helped keep the fanwort population under control in shallow waters. A more significant draw-down might help decrease the fanwort population, but "I don't think it's absolutely critical," said Kortmann.
He also noted the presence of a band of another aquatic plant, tapegrass, at about 3 to 5 feet below the lake's surface. "Some people may find that objectionable," said Kortmann, but "in general it's a desirable plant to have."
The tapegrass provides a good habitat for fish, he said, and doesn't usually interfere with recreation use of the lake.
Kortmann told the commissioners that the lake is also home to bladderwort, a plant not considered an invasive species that can be an indicator of good water quality.
The lake has "a very healthy plant community" overall, he said.
The lake's water quality data haven't changed much since 1996, said Kortmann. There are "pretty similar conditions … which is a good thing [that] shows that the lake is pretty stable," he explained.
He told the commissioners, who have started collecting water quality data as part of a cooperative water monitoring program with Ecosystem Consulting Service, not to draw broad conclusions from slight year-to-year differences that are probably related to weather and climate changes.
He also warned the commissioners to be careful with weed control systems, which can sometimes end up changing "the state of the lake from plant growth to algae growth."
The commission should be concerned if the water starts to turn gray-green and transparency goes down during summer months, said Kortmann, but "I don't think you're going there - the data is very good."
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