Troubling Algae Bloom Subsides

Wednesday, September 04, 2013
Enfield — State officials on Tuesday reopened two popular access points on Mascoma Lake after higher than normal levels of cyanobacteria led officials to close the two swimming areas over the holiday weekend.

The state Department of Environmental Services confirmed Friday that the water near Enfield’s Shakoma Beach and the Dartmouth College Sailing Facility, which has boat docks and a swimming beach used by members of a summer yacht club, tested positive for elevated levels of cyanobacteria, a blue-green algae that gives the water a cloudy appearance.

At about 2 p.m. on Tuesday, both beaches were still posted with red advisory signs warning of the contamination and stating that the water was unsuitable for wading or swimming.

Beachgoers could have disregarded those signs, however, according to NHDES Beach Program Coordinator Sonya Carlson, who said the warning was lifted earlier Tuesday after officials retested the water and concluded bacteria levels had returned to normal.

Carlson said an individual alerted the department to the possibility of cyanobacteria in the water on Aug. 28 and after performing tests two days later, results came back positive.

“I would say that it (was) present, but not in extreme amounts,” Carlson said in regard to the level of contamination.

The warning applied only to the swim beaches, not the entire lake.

Carlson said officials perform three tests annually on the lake, mainly for E. coli, unless officials see signs that other bacteria may be lurking. Officials performed routine E. coli tests at Shakoma Beach and the sailing facility on Aug. 13 and cyanobacteria was not evident at the time, Carlson said.

Shakoma Beach also tested positive for E. coli — a bacteria that indicates fecal contamination — during the routine E. coli test. An advisory was issued, but the E. coli level has since returned to safe levels.

Carlson said there is nothing that can be added to the water to lower the levels of E. coli or cyanobacteria. If the levels don’t decrease on their own — like they did in the two Enfield cases — long-term management plans are weighed.

“You can’t just add chlorine to the lake if you wanted to kill the bacteria,” Carlson said. “That’s not legal.”

Enfield Town Manager Steve Schneider said it isn’t uncommon to see higher bacteria levels in the water given the current weather patterns.

“It’s hot and sticky and there hasn’t been a lot of wind to move the water around,” Schneider said.

The life-guard season at Shakoma Beach has drawn to a close for the summer, but the beach remains open to the public.

The college’s sailing facility hosts a yacht club in the summer. John Brady, the sailing facility’s summer manager, said the club’s summer season ended Monday. Even though the ban cut into the club’s final weekend, Brady said the impact was minimal.

“Given the weather, it (the ban) really didn’t affect us,” he said. “It really didn’t make a significant difference.”

Dartmouth’s varsity sailing team, which could be seen practicing Tuesday, continued to use the sailing docks despite the warning.

“They are a national champion team this year. We don’t have to worry about them not staying in their boats,” said Brady of the team, which started practice on Monday. “They are pretty capable.”

Jordan Cuddemi can be reached at jcuddemi@vnews.com or 603-727-3248.