Does PWD control the level of water in Sebago Lake?

No. The dam that controls the level of Sebago Lake is owned by SAPPI (formerly SD Warren) in Westbrook. SAPPI is required to manage lake level according to a compromise plan, developed in the 1990s by individuals, groups, and state agencies who had differing points of view about the best plan for managing the level of the lake. The compromise plan has target levels for certain weeks of the year. Drought years are built into the compromise plan.


Does the PWD have authority to control uses of the lake?

Some. The PWD is recognized as the primary entity responsible for promotion and oversight of lake protection issues in the Sebago Lake region. The PWD's Watershed Control Program relies on the support of other regulatory authorities - local, state, and federal - and on education and outreach to impact other human activities that are not governed by any law or regulation.

Can I use fertilizers and pesticides around the lake?

The PWD promotes minimizing the extent of mowed areas near the lake because natural woody vegetation provides normal cleaning of runoff. The PWD does not use chemicals to treat the lawn areas at its properties near the lake and encourages others to use non-chemical lawn care methods as well.

If the PWD built a water filtration plant, would there still be a need for lake protection?

Absolutely. The PWD was granted a waiver from the filtration requirements of the Safe Drinking Water Act in part because lake water quality is so high. The PWD believes the waiver to filtration saves our customers a significant amount of money without compromising the protection of their health. And we are committed to protection of the source as one component of our effort to maintain the waiver. But PWD was committed to protecting Sebago Lake before the waiver and will continue to protect the lake as long as it is a source of drinking water, regardless of the type of treatment used.


There is foam accumulating on the lake? Is this indicative of pollution?

Most lake foam is caused when the surface tension of water is decreased and air is mixed into the water. Organic materials from naturally decaying plants and animals can reduce the surface tension of water, and when the wind blows across it, or waves wash against the shore, bubbles are produced.

Most foam observed in lakes or streams is naturally occurring, and not an indicator of pollution.


Is Sebago Lake clean?

Very! Sebago Lake is relatively young, as lakes go, is underlain by tough Sebago granite, and its watershed is mostly forested. The greatest threats to any lake’s cleanliness come from human activities. Sebago Lake is the deepest lake in New England and contains almost a trillion gallons of water. This doesn’t mean it’s invincible, but it takes more effort to pollute that much water. Put all these factors together and you have one of the nation’s finest water supply lakes.

How deep is Sebago Lake?

For years it was commonly believed that the deep hole of Sebago Lake reached down to 316 feet. A recent survey, however, has measured the maximum depth at 307 feet. Still, this makes Sebago Lake the deepest lake in all of New England. If you were standing on the bottom of the “deep hole” in Big Bay, your feet would be 41 feet below sea level!

What is lake turnover?

In the summer, the lake “stratifies” or develops layers of different temperatures that do not mix. Perhaps you’ve noticed the effect– have you ever kicked into a cooler layer while swimming at the warm surface? As fall nights chill the lake’s surface, the top layer of water cools, becomes heavier, and eventually sinks. Water that was at the bottom of the lake is displaced– it rises to the top, bringing with it lots of bottom nutrients. Fall winds mix these layers, distributing oxygen and nutrients from top to bottom, until ice forms.

How does the lake freeze?

In the fall, when water cools, it becomes more dense and sinks to the bottom of the lake. Water is “heaviest” at 39 degrees F. As winter nights cool the water from 39 degrees down to 32 degrees, it expands and freezes! Expanded, frozen water (ice) is less dense, and lighter, so it floats! The fact that ice forms from the top down is lucky for fish and lucky for us - the ice acts as an insulator; and the heavier water at the bottom remains in its liquid form.

Is it OK to feed the ducks on Sebago Lake?

Resist the urge to feed ducks or any water fowl. “People” food is far less nutritious to a duck than its normal diet. Handouts may cause ducks to become tame and more exposed to natural predators. Migration could be delayed. Ducks are perfectly capable of finding food, unless they have become overly dependent on human handouts.

Duck feeding causes problems for people, too. Duck waste may contain bacteria and parasites that are unhealthy for humans.