Windham council gets science update on Highland Lake

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WINDHAM — The Town Council received an update last week on the scientific effort to understand a mysterious, temporary cyanobacteria bloom that’s been occurring at Highland Lake during part of the last few summers.

Questions about the bloom and concerns about its environmental and economic implications have ignited a discussion about the lake’s health in both Windham and Falmouth. The issue prompted the Windham Council to pass a moratorium on certain development activities in the Highland Lake watershed. It also led to the creation of a joint Highland Lake Leadership team, with representation from both towns.

After saying they wanted more information about the science behind the problem, the council on Tuesday, Jan. 30 heard a presentation from Don Kretchmer, a water resource consultant from New Hampshire. Kretchmer was hired by the Highland Lake Association to help summarize the group’s recent science forum that took place in December. Jeff Dennis from the Maine Department of Environmental Protection joined Kretchmer in the discussion.

“The question is, why here and why now, and that’s what we’re trying to figure out,” Kretchmer said about the bloom and determining what makes Highland Lake unique.

Lake Association President Rosie Hartzler said the forum was closed to the public so the scientists, water quality experts and others involved could focus on the scientific process.

Hartzler said the association will be holding a public event on March 7 to further outline the discussion from the science forum.

Last week, Kretchmer outlined various factors involved in lake health and offered some possible explanations for what’s happening in Highland Lake. Those possibilities include increased phosphorous levels and changes in weather and climate.

Kretchmer and Dennis also acknowledged that the reintroduction of alewives into Highland Lake could possibly have a role in the bloom.

According to Dennis, the timing connected to the first full cycle of alewives returning to the lake coincidentally lines up with when the Highland Lake bloom was noticed four years ago.

Based on a general outline of the lake’s food chain, Dennis said the young alewives “feed heavily” on the larger zooplankton that, in turn, feed on algae like the cynanobacteria that’s been blooming, and could possibly be allowing the cynanobacteria to thrive.

“There may be a cascade effect there,” Dennis said about a possible impact from the alewives on the lake’s food chain. “That could be what’s triggering this bloom.”

Councilor Timothy Nangle asked if shutting off the fish ladder for a year would be a way to know if alewives were part of the process.

Dennis said the move “would be a way to test it” and see what impact alewives might be having, but it would be “politically difficult.” He noted there are other ways to explore whether that’s part of the problem.

A document from Kretchmer to the council and lake association indicated that the cyanobacteria is the only known bloom of this genus in New England, although this genus is commonly present in lakes.

“It’s unique,” Dennis emphasized about the bloom after the presentation last week.

Kretchmer emphasized that every property owner in the watershed can probably take some sort of action to help the lake’s health. Earlier in the presentation, for instance, he noted the importance of being cognizant of the amount of phosphorus in lawn fertilizer.

“This is not a silver bullet solution, this is like a shotgun solution,” Kretchmer said. “Every parcel has something that can be done a little better to protect Highland Lake.”

Matt Junker can be reached at 781-3661 ext. 123 or mjunker@theforecaster.net. Follow him on Twitter: @MattJunker.

Keith Williams of the Highland Lake Association takes readings during water testing and sampling at Highland Lake this past summer.

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