The invasive aquatic plant hydrilla was found recently in Davis Stream in Jefferson. The infestation is the second instance of the plant in the Damariscotta Lake watershed.
In addition to removal efforts already underway in the stream, officials from the Maine Department of Environmental Protection are pursuing restrictions on surface activity beginning about 200 feet upstream of the Jefferson Market.
For now, all boaters are strongly encouraged to stay out of the stream.
“If you’re in a boat in water that contains hydrilla, you’re contributing to the problem,” said Paul Gregory of the DEP Invasive Species Program. Even if boaters remove the plant from their equipment to avoid spreading it to other lakes, boating in infested waters spreads the plant to new areas of the infested lake.
Some flexibility is available in surface use restrictions, and the terms of this request have not been set. Gregory said the department hopes to have the restriction in place by next week.
Hydrilla is known to have infested two lakes in Maine, including Damariscotta Lake. DEP is worried about the spread of the plant to others waters, which is why they responded so swiftly to Davis Stream.
In most lakes facing invasive species such as milfoil, removal and other control efforts are left to local, DEP-trained volunteers. “We only work on the most critical sites,” Gregory said. Definition of “the most critical sites” includes any water containing hydrilla.
“Hydrilla is the worst invasive species in North America,” Gregory said. It has severely impacted some southern states for several decades. Florida, for example, reportedly spends millions of dollars each year to mow the hydrilla in their waterways to keep them navigable, Gregory said.
Gregory was speaking from a canoe in Davis Stream in the morning on Sept. 20, as DLWA volunteers joined him and three others from DEP in a daylong removal effort.
“Because it’s only in two lakes, we can throw everything at it,” Gregory said. There are three members of the Invasive Species Program – Gregory, John McPhedran and Karen Hahnel – for every lake and pond in the state, all of whom were on scene on Sept. 20. DEP Lakes Program member and top diver Denise Blanchette joined the trio.
The first infestation found in Damariscotta Lake is in Cranberry Cove, .3-acre lagoon near an area of the lake known as the Narrows. That location has been contained – though not eradicated – through extensive action from the DEP and local volunteers.
Damariscotta Lake Watershed Association volunteers have been surveying Damariscotta Lake since hydrilla was discovered, and it has not been found in any other parts of the lake.
“This is discouraging,” said Julia McLeod, stewardship coordinator for the DLWA. “We were feeling confident about containment, but this raises questions about whether it could be someplace else in the lake.”
Ray Hayes, a resident who lives on Davis Stream and frequently kayaks in the area, first discovered the Davis Stream infestation in a weedy cove about a quarter-mile upstream of the Jefferson Market on Sept. 6. Davis reported the infestation to the DLWA and Gregory confirmed the infestation that afternoon.
Since its discovery, officials have surveyed “99 percent of the stream” and found six pockets of hydrilla – three dense patches and three “sprigs,” Gregory said.
On Sept. 20, they removed seven heavy-duty trash bags of hydrilla from the stream. In one location, sheeting called a benthic barrier will placed on the bottom of the stream to prevent the hydrilla from re-growing.
However, in the other locations, concerns about heavy currents in the spring will prevent the use of benthic barriers. This all but ensures that more removal will be needed next year.
Gregory said benthic barriers will be put down next year after the spring flows have subsided.
“Hand removal of hydrilla will become a part of life” in Davis Stream, Gregory said. He added he is confident that the infestation was discovered early enough that containment efforts will be a success. Gregory said one of the sites appears to be new this year, but another larger site in the stream is at least two years old.
It’s unlikely that Damariscotta Lake will ever be completely free of hydrilla, but with vigilant containment efforts, its impact may be limited.
“The sky isn’t falling,” Gregory said. “We’re not out here doing this as an exercise.”
Another important effort is containing the plant to the lake. Preventing hydrilla from spreading around the state is a major emphasis for DEP, Gregory said.
“We’re hoping that through education efforts we can make checking your boat and trailer a part of lake courtesy,” he said. “You wouldn’t feel comfortable about throwing a piece of garbage on the ground; that’s because of littering outreach programs.”
DEP will continue to monitor Davis Stream throughout the fall, but the hydrilla growing season has largely come to an end, Gregory said.
DLWA volunteers will continue to survey the lake and monitor existing hydrilla infestations. In the future, DEP-trained volunteers will likely handle ongoing hand removal efforts.
Anyone who thinks they may have seen an invasive species is encouraged to leave the plant alone and call the DEP Invasive Species Program at 287-3901.
Attempting to remove the plant may spread it. Also, many native plants look similar to invasive plants, but are beneficial to the local ecosystem and should not be removed.
McLeod said residents who find possible invasive species should “very carefully” collect a small sample of the plant and bring it to DLWA headquarters at 38 Lake Farm Rd. in Jefferson for testing.
Anyone interested in volunteering, or seeking more information on hydrilla and the ongoing efforts to combat it, may call the DLWA at 549-3836.
