Waldo County’s largest lake has a history of severe annual summertime nuisance algal blooms. Water quality has been in decline since at least the 1970s. As a result, Unity Pond is on the Maine DEP list of impaired lakes due to non-point source (NPS) pollution and internal sediment recycling of phosphorous (P). Some sources of pollution have been removed. Unfortunately, however, the lake is currently threatened by NPS pollution from development, including agricultural development, residential and commercial development, and roads. Pollutants that have built up in the lake’s sediments also pose a threat to the lake. In addition to being listed on the State’s NPS Priority Watersheds List as an impaired lake, Unity Pond is listed as “Most at Risk from New Development” under Chapter 502 of the Maine Stormwater Law because of its history of severe blooms and internal P recycling.

Unity Pond covers 2,569 acres and is located in the towns of Burnham, Troy, and Unity in the western part of the county. It drains approximately 30 square miles of the surrounding landscape. Numerous tributaries flow into Unity Pond, including Carlton Stream, Bog Brook, Bithers Brook, and Meadow Brook. The watershed includes 3,418 acres of wetlands, and 4,335 acres of riparian habitat along the edges of lakes, ponds, streams, and wetlands. Water flowing out of Unity Pond flows south under the train trestle on the southwestern shore and into Sandy Stream, then Twenty-five Mile Stream, northwest to the Sebasticook River, south to the Kennebec River in Winslow, and eventually into the Gulf of Maine. The lake’s maximum depth is 39 feet with an average depth of 17.5 feet and a flushing rate of 1.28 flushes/year. The deepest location in the lake is near the lake’s outlet on the southwest end of the lake, with a smaller “deep hole” further to the northeast.

Water quality data have been collected consistently since 1977 at the deepest location in the lake by Maine DEP and Lake Stewards of Maine Volunteer Lake Monitoring Program. Between 2000 and 2019, four water quality, pollution, and watershed surveys were conducted, and two action plans were produced. Since 1991, eight series of activities have been implemented to address pollution. The previous Watershed-based Management Plan (WBMP) was prepared in 2006.

The 2023-2032 Watershed-based Management Plan is now available. Click below for the plan, the final project report to Maine DEP, and a flow chart explaining the process.

Related Resources

In 2020, our office partnered with Friends of Lake Winnecook, Ecological instincts, and others to seek funding from the U.S. EPA and Maine Department of Environmental Protection (DEP) to update the 2006 WBMP. Intensive monitoring began in 2021. This information and historical data were used to conduct a water quality trend analysis for Unity Pond, evaluating both long-term (1977-2021) and short-term (2012-2021) trends.

To read about the results of these analyses, and recommendations for a 10 year action plan to reduce pollution and frequency of nuisance algal blooms in the lake, please refer to the updated 2023-2032 Unity Pond Watershed-based Management Plan (see links on webpage).

If you would like to help, please contact Friends of Lake Winnecook to learn how you can play a part in this extremely important 10-year effort (link to FOLW at right)! There is a lot of work ahead and it will be worth every minute, and every dollar, in order to improve the health of this beautiful lake.  When the community comes together, great things can and will happen!