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Songo Locks Milfoil Update

October 18, 2010 - Bridgton News Editor’s note: The following column by Lakes Environmental Association Executive Director Peter Lowell will appear in their upcoming newsletter, giving an update on LEA’s efforts to stop the spread of milfoil from the lower to upper Songo River. Lowell said Monday the state is against dredging, because milfoil loves disturbed areas, and has recommended benthic barriers as the best solution, preferring not to close the Lock temporarily as LEA has requested. But Lowell said the cost of the benthic barriers is way beyond LEA’s resources, and they are trying to line up partners before moving forward. “It’s going to take a commitment on the part of the next administration in Augusta to make sure this is done well, and not just swept under the rug,” he said. The increased boat inspections done this summer at the Lock (4,400 were inspected) “was a help, but it’s not the answer” because there’s no way the boats can be thoroughly inspected, he said.

By Peter Lowell
LEA Executive Director

The Lakes Environmental Association has spent five years and almost $250,000 working to clean the upper Songo River and Brandy Pond in Naples. Brandy Pond outlets to the Songo River, which is a major tributary of Sebago Lake.

When LEA began work, there were about three acres of variable milfoil in the river and at marinas in the pond. Much of the river was heavily infested and the patches of plants at the marinas were spreading.

The Libra Foundation awarded LEA a grant to help clean up the milfoil and develop innovative control methods. LEA pioneered the use of blue “Mainer” tarps to tackle the extensive plant beds. The tarps measured 40 feet by 60 feet, allowing us to cover substantial areas relatively quickly. Specific information on this technique is available by contacting us.

The big tarps allowed LEA to get a jump on the infestation and reduced the acreage by about two-thirds. The Little Sebago Lake suction harvester then became the model for our new S.S. Libra harvester, which utilized a custom-made aluminum sluiceway. A few more tarps and suction harvesting finally brought the infestation under control in 2009.

This year efforts were limited to suction harvesting and hand pulling of renegade plants. In 2010, LEA staff removed a total of 100 onion bags of plants from Brandy Pond and the Upper Songo. This was a significant reduction from previous years, and the waters were cleared of plants earlier in the season. LEA hopes in another five years to reduce the infestation to just a few random plants or patches that will require yearly maintenance harvesting.

The apparent success in the Songo-Brandy waterway is the largest infestation to be brought under control in Maine and there is strong optimism for eventual eradication. The flip side to this story is the lower Songo River. Below the Songo Lock is a mile or so of river that is heavily infested and it’s one of the busiest waterways in Maine.

In 2010, LEA Courtesy Boat Inspectors checked more than 4,400 boats at the Lock, the majority of which were headed upstream to the upper river, Brandy Pond and Long Lake. Another 1,000 inspections were conducted at the nearby Sebago Lake State Park boat launch site where more than 50 intercepts of variable milfoil were recorded.

In early July, LEA was alarmed about the explosive growth of the plants below the Lock after boat inspectors reported lots of plant fragments in the Lock. Making matters worse, in May and June, boats traveling through Songo Lock increased 87.5 percent compared to the same period in 2009. This led to a request to the DEP and Department of Conservation, which runs the park, to consider closing the Lock to boat traffic. We did not want to see five years of work and investment reversed.

LEA also started a successful campaign to tell boaters about the infestation on the lower Songo and encourage them not to go through the Lock. By the end of July, traffic already had started to level off, but it still was 27 percent higher than in July 2009.

In August, as the media began running stories about LEA’s efforts to protect the Upper Songo, Brandy Pond and Long Lake, the traffic on the Lock began to slow dramatically. August boat traffic actually dropped 7.4 percent compared to August 2009 and September traffic was 47 percent lower than in 2009.

So despite the big increase early in 2010, the May through September total for 2010 was only slightly (7 percent) higher than last year.

The state agencies ultimately denied the request to close the Lock but placed more channel markers in the river and increased funding for inspections at the Lock. These measures were clearly helpful. In several instances, inspectors took armloads of plants off props, emphasizing the danger to upstream waters.

The LEA proposal to close the Lock was opposed locally by marinas, especially those that rented boats. The debate, however, was never contentious. All parties recognized the threat but differed on their ideas for solutions. The debate will surely be re-kindled before next summer.

From LEA’s perspective, the risk of infesting Long Lake and reversing the progress above the Lock is simply not worth taking. We asked our members and the boating public to avoid the trip through the Lock and lots of people responded. And, many boaters who spoke to inspectors seemed supportive of closing the Lock.

The only way to make the Lock safe is to eliminate the plants from the lower Songo River. A DEP consultant who toured the river this summer recommended increasing the channel markers. The only control method he saw as viable was benthic barriers.

LEA has a design for a barrier suitable for the river shoreline banks where most of the plants are found, but this project is way beyond our resources.

Sebago Lake and the Songo River present an enormous threat to all of Maine’s uninfested lakes, and, in our opinion, they need to be cleaned up or better safeguarded. This is a contagion that could ruin Maine’s lakes, and local economies.

LEA will be working this winter to review resources, partnerships and strategies to address this problem. It will only get worse until something meaningful is done.

The Bridgton News, Oct. 14, 2010


Lakes: Brandy Pond, Long Lake, Sebago Lake
Regions: Sebago


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