People interested in the welfare of local lakes who take time to inform themselves will .nd both more issues of concern and more opportunities to help out.
Jim Chandler of Woodstock and the Community Lakes Association presented information on the effects of climate change and human activity on lakes at last week’s Mahoosuc Land Trust’s “The Changing Nature of Lakes and Ponds.” He outlined some generally familiar trends and concerns, including the flow of nutrients into lakes from erosion, earlier ice out dates in recent decades and the presence of invasive milfoil plants in some area lakes.
He also described how some of those developments interact with, or may be caused by, climate change.
Ice out dates may be the most apparent tie to climate change. Chandler showed U.S. Geological Survey graphs from 29 lakes in New England (22 in Maine) showing ice-out dates have become significantly earlier since the mid-1800s. They changed on average by nine days between 1850 and 2000 in the northern and mountains areas of western Maine, and by 16 days in more southerly locations.
Nutrients and warming
Nutrients carried into a lake can cause more plant growth, and as those plants die, the plants are decomposed by bacteria and fungi that uses up the oxygen in the water. That can be unhealthy, particularly for fish such as trout or salmon, which prefer the higher- oxygen cold water. A potentially warming climate can add to the effect because warmer water holds less oxygen than cold water.
Chandler cited data collected over recent decades for the amount of dissolved oxygen in area ponds. The data from the Maine Department of Environmental Protection, Lake and Watershed Resource Management Associates. (LWRMA) and the Volunteer Lake Monitoring Program through 2006 shows less oxygen near the bottom of some of the lakes during the summer.
Among specific lakes: North Pond in Woodstock shows low to moderate dissolved oxygen depletion in deep areas of the lake; South and Round ponds in Greenwood show high depletion, although in recent years this has improved greatly; Bryant Pond (Lake Christopher) in Woodstock shows moderate to high depletion; and Songo Pond in Albany shows moderate depletion.
Chandler said the Community Lakes Association has participated in the lakes monitoring program and the oxygen depletion measurements have not changed much over the recent years. The CLA monitors 11 lakes and ponds in the area.
He also said some lakes are getting cleaner as measures are taken to prevent pollution.
Lake Smart
People who live on a lake can educate themselves and support the health of the lake through the Lake Smart program, formerly offered by DEP but now operated by the Maine Lakes Society, in cooperation with a local lake association. A trained evaluator will visit and assess property in five categories: road, driveway and parking areas; structures and septic systems; lawn, recreation areas and footpaths; shorefront and beach; and undeveloped land.
The program focuses on stabilizing eroded areas, reducing the use of chemicals, diverting rainwater into vegetated areas, and maintaining or planting trees, shrubs and ground cover along shoreland.
Chandler said such vegetation holds runoff water better than grass.
He said that locally, the Oxford County Soil and Water Conservation District has been involved with the Lake Smart program, and the CLA is interested in starting one in the area.
Lake Smart had been limited in its activity in recent years, said Chandler, but now that the Maine Lakes Society is running the program they are looking expand the participation.
Milfoil
Chandler also updated the local fight against the invasive variable-leaf milfoil plant, which has been growing in both Lake Christopher and Shagg Pond in Woodstock in recent years. The plants can choke lakes and make boating and swimming difficult. And the sheer mass of plants decaying can also contribute to oxygen depletion, he said.
Chandler said the lake association has made progress in removing it from Lake Christopher, but because the plant had spread significantly in Shagg Pond and the lake is infestation is in an open area, the goal will be to manage and contain it.
Fighting milfoil is not cheap. Chandler estimates that about $160,000 in private, grant and inkind funds has been spent over the past decade in the local effort.
A concern last year was the discovery of milfoil in the swampy pond area on the other side of Rowe Hill Road from Lake Christopher, where the Little Androscoggin River starts.
“We have done some control work in that area but have much more to do,” Chandler said after his presentation. “We checked further down in the Little Androscoggin River but did not see any live or dead plants. They do not do well in shaded and moving water. We had the same concern in the Neizinscot from Shagg, but it is not spreading. Always a little concern, but it seems a minor risk from our observations and we are monitoring the situation.”
Chandler summarized, using a 2010 “The State of Lakes in Maine” Report done at Colby College, “Out of Maine’s 5,785 lakes only 24 have invasive aquatic plants, and about 30 lakes are considered impaired, and these numbers have stayed fairly stable in recent years. Maine has more lakes, better water quality and fewer infested lakes than any other New England state. The lakes in our area tend to have average or above average water quality compared to other lakes in Maine. There are many potential threats affecting Maine lakes but if we remain vigilant and people continue to get involved in protecting water quality we will be able to sustain this valuable resource.”
Comments are no longer available on this story