Onota Lake drawdown draws concern for affected wildlife
This story has been updated to correct the unit of measure in an observation made about water level on Dec. 21
PITTSFIELD — This winter's deep drawdown of Onota Lake has exposed not only a stunning view of the lake's bottom but also a swell of citizen concerns about the impact this method of lake management has on its flora and fauna. It's now also prompted a response from two state agencies.
While drawdowns are a common lake management method, spokespeople from both the Massachusetts Division of Fisheries and Wildlife (MassWildlife) and Department of Environmental Protection said they have fielded reports made by concerned citizens in December about the drawdown depths and the impact on wildlife specifically at Onota Lake.
Opening dams to dewater lakes has been a long-used method for everything from flood control to invasive weed management.
For decades now, the city has conducted annual drawdowns at all its lakes beginning in the fall and refilling in the spring. The intent is to expose the bottoms of shoreline areas to a hard winter freeze to help kill off invasive weeds, like Eurasian watermilfoil, which tend to tangle swimming and fishing areas and snag in propellers and oars.
"We have a multi-pronged strategy that involves drawdowns and chemical treatments," said the city's Park, Open Space and Natural Resource Program Manager James McGrath, who also serves as the municipal harbormaster.
In 2017, to combat unruly weeds, herbicide treatments were increased at Onota Lake, from one annual application to two, on June 1 and Aug. 15, respectively. The city uses the chemical Diquat, which kills Eurasian watermilfoil foliage on contact.
In the fall, the typical annual drawdown depth at both Pontoosuc and Onota lakes is about 3 1/2 feet below spillway elevation. But this year, according to McGrath, he exercised permits that allow his department to conduct a deeper drawdown at Onota of approximately 5 1/2 feet.
This permit, granted by the city's Conservation Commission, in accordance with state water management laws, allows for such deep drawdowns to take place every three years, as needed.
An attempt to do a deeper drawdown at Onota was made last year, but the weather conditions weren't favorable for it to be effective. Since then, the weed growth has not significantly subsided. So, in addition to the two herbicide treatments, a second attempt at deep drawdown at Onota began back on Oct. 16. The intention was to leave it at that low level for at least the 10 to 14 days needed for an effective weed-killing freeze, then to slowly bring the levels back up by April 1, as mandated by the permit.
But by late-November, to residents and sportsmen and other users of the lake, something seemed amiss.
A dramatic shift
"What's with the lake?" asked Angel Yee, who sent in a photo of the shore to The Eagle, noting that the water at this popular destination looked "dried up."
The landscape and shoreline definitely underwent a dramatic-looking transformation. By that time, visitors to the area of Onota Lake's Controy Pavilion, by the north parking lot, could easily step onto the freezing earth of the exposed shoreline and walk out for dozens of feet.
By mid-December, pedestrians could walk clear across this portion of the lake — on frozen earth, not ice. Old tree stumps, chains anchored to concrete blocks and debris broken from boats and oars once lost on the the lake bottom could now be found in plain sight.
But just as the desired drawdown exposure occurred, snow came in, acting as an insulator. McGrath said that again, for a second season, the attempt for a prolonged, milfoil-killing exposure to frost and ice had failed. So, he said, his department has begun filling the lake back up to the typical drawdown level of between 3 and 4 feet.
But some city residents and lake watchdogs think the damage from this year's deep drawdown is already done. Dewatering the shore area had not only exposed a mixture of native lake plants, invasive weeds, and debris, it made some lake animals and their homes prone to dry land and the winter elements as well.
"I feel like this drawdown is lower than in previous years," said Tom Dailey, who sits on the board of directors for the Lake Onota Preservation Association. He's also owned the lakeside Onota Boat Livery marina and retail store since 1991.
A DEP spokesperson said that after receiving two calls on Dec. 22, officials "are looking into it," but offered no further comment on the department's involvement in the matter.
A MassWildlife spokesperson confirmed that members of its staff visited Onota Lake on seven occasions in the past two months. During some visits, the agency was monitoring lake levels. On Dec. 14, officials visited Onota's outlet structure and observed the levels to be between 7 and 8 feet below the spillway versus the permitted 5 1/2 feet.
The city has an automated telemetry station that tracks water levels from the side of the dam. McGrath told officials that the sensor on the system can get hung up, so he began tracking depths manually between Dec. 1 and 17. During that time, he reported that "fluke" dips to 7 feet occurred on Dec. 2 and Dec. 14. He said those levels were remedied by closing an outlet valve.
In a Dec. 18 email correspondence with officials McGrath wrote, "There was no period of time when the main part of the lake was out of the range of drawdown compliance. [There] was no period of time when the north section of the lake was out of drawdown range compliance. There was a short window of time when the area in the immediate vicinity of the dam was out of compliance, and this condition — when observed — was corrected within minutes."
That day, he reported that the lake measured 4 1/2 feet below the spillway, and that he was in the process of bringing the lake back up to the typical drawdown level of 3 1/2 feet, "where it will remain until refill."
On Monday, Feb. 12, McGrath reported that the lake is now compliant, at 3 feet below the dam.
Animals appear 'stranded'
MassWildlife, in the meantime, is gathering and reviewing data and samples to determine any short- or long-term effects the drawdown at Onota has had on the ecosystem and its inhabitants.
City resident Dan Miraglia has actively been contacting both local and state agencies about this matter, and requesting more thorough reviews. A lifelong resident, Miraglia said he and his siblings were raised on the city's lakes and in its forests, learning to fish and hunt and act as environmental stewards for the land and water. He has also volunteered in various roles on area lake associations, which are integral agencies for the health and vitality of local lakes.
In addition to city officials and volunteers doing regular monitoring of lake water levels and weed concentrations — something Miraglia also does on his own time — he believes field biologists and/or other lake professionals "should be surveying wildlife changes" each year to offer a professional understanding of how different lake management techniques affect native plants and animals living there.
Miraglia became particularly concerned in December when he visited the lake on multiple occasions. On Dec. 21, he took a photo of freshwater mussels submerged in about 5 inches of water, in an area called "the channel" that had a flowing current of water running through a sandbar in the northern part of Onota Lake. In a Facebook post, he wrote about a follow up visit. and said that "on dec. 29 there was no water flowing through the channel and all the mussel beds have been exposed to freezing and killed by the deep drawdown at onota lake."
On Jan. 3, Miraglia met The Eagle in the same area on the lake. Brushing off areas of snow, and around a sandbar, some dead vegetation could be found, but it consisted of a mix of grasses and weeds, not solely Eurasian watermilfoil.
Over the course of a walk across Onota, mussel beds could be found both in plain sight and just under the snow, their shells open, exposed, cracked. Some mussel shells were accompanied by bird and raccoon tracks in the surrounding sand and snow, indicating that without the cover of water, they may have been spotted and eaten by predators.
Miraglia stopped, looked down and shook his head. "They're all dead," he said. "They're vital to the ecosystem."
Over the course of their seven site visits between Dec. 14 and Jan. 18, to document water levels and other effects on Onota, MassWildlife agents reported observing "a number of mussels dead as a result of stranding." The mussels were primarily Eastern Lampmussel (Lampsilis radiata radiata) and Eastern Elliptio (Elliptio complanata). Both are native species, unlike the malignant invasive zebra mussel, and both are species considered by biologists to be organisms critical for maintaining water quality due to their abilities to filter bacteria and other potentially harmful substances in water.
On Jan. 17 and 18, MassWildlife also responded to a call and "observed muskrats which appeared to have been stranded and trapped in shallow water."
McGrath says to-date, he has "not heard or seen any reference to mussel or muskrat strandings," nor has he since received any correspondence from MassWildlife. An agency spokesperson on Feb. 1 said that regarding Onota Lake, "There have not been any additional site visits and MassWildlife is reviewing the findings of its visits to determine next steps."
Future plans needed
In the meantime, McGrath, in collaboration with lake association groups for Onota and Pontoosuc, and Richmond Pond, and the city's Conservation Commission members, are thinking about the future of lake management, and how to address any issues that might be brought up by members of the public, residents around the lake or state officials.
Existing long-range lake management plans for both Onota and Pontoosuc lakes, which can be found on the City of Pittsfield website, are both nearly 14 years old. The Richmond Pond plan was updated in October 2016, as prepared by the Richmond Pond Association.
The city's deep drawdown permits expire on Nov. 24, 2019, according to records kept by city Conservation Commission conservation agent, Robert "Rob" Van Der Kar. This too, will have to be revisited.
One of the biggest perennial issues with lake management is cost, both in terms of money and manpower.
Drawdowns are still one of the cheapest forms of lake management, basically the manpower of opening and shutting a dam. In fiscal 2017, the city's allocation for overall lake management was $35,000, with approximately $22,000 designated for weed treatment at Onota Lake, and $8,500 for Pontoosuc, McGrath said. He said the city is currently looking into applying for a state Water Quality Management Planning grant, known as a 604b, to help aid lake management plan updates. This grant is due in March, said McGrath, and "if we apply we would be seeking approximately $30,000."
In also looking ahead, folks like Dan Miraglia and Tom Dailey hope that the city addresses the issue of lake weed control with more pragmatism and hard questioning about what's effective.
Dailey said he doesn't think the drawdown approach is working like it should.
"If it's working, [the city] should be using less chemical treatments, not more."
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