The Basics...Mill Pond is a small waterbody located in Searsport. It is approximately 2 hectares (5 acres) in size and supports some warmwater fish species. It was historically a larger waterbody, but sediment deposition -- in part, due to beaver dams slowing down the water -- has transformed its northern end into marshland (as seen in photo by Peter Taber). It is a freshwater system although it is located only 9 m (29.5’) above sea level and in close proximity to the ocean. A significant reason for this is the small impoundment, which State of Maine records indicate was constructed in 1900 and is owned by the Town of Searsport. The impoundment is ~4.9 m (16’) high and has a ~4.3 m (14’) hydraulic height. This substantially separates the pond from the tidal cycles that could result in a saltwater intrusion, which, in turn, could dramatically change the water quality and habitat of the waterbody. While the processes of gradual sediment deposition and beavers damming at the northern end can be considered natural eutrophication, human manipulation of the environment is also at play here, even in the possibility of Mill Pond as an existent pond and not a saltwater marsh. The issues associated with impoundments, and of their removal are often complex and require significant understanding of the changes that could occur to an ecosystem, both what is gained and what is lost.
Eutrophication: Cultural vs NaturalOften eutrophication is viewed as a harmful and unnatural process. This process needs an adjective in front of it though to describe what type of eutrophication is or has taken place: cultural or natural. A fundamental difference between these two is the element of time.
We have collected some spectacular aerial videos of 26 Maine lakes, all captured by drones and published on Youtube or Facebook.
To view this collection, click on the image below.
The year is 1937. Across the Atlantic, the Spanish civil war is raging. Somewhere over the Pacific, Amelia Earhart is last heard from. In the US, FDR opens the Golden Gate Bridge; the Hindenburg airship is destroyed at Lakehurst NJ; Spam is first sold in food stores. And, in Maine, Gerald Cooper, a faculty member at UMaine, begins the first systematic survey of the water quality and biology of Maine lakes (and some streams). During this first year, Cooper focuses on streams and a few lakes in York and Cumberland counties. Over the next 7 years (with a break during the war year of 1943), Cooper and colleagues survey over 200 lakes, ending up with Moosehead and Haymock Lakes in 1944.
A key reason for the Cooper surveys was to evaluate lakes for fish-stocking. They collected data on: lake depth, water temperature, dissolved oxygen, pH, phosphorus, benthic invertebrates, and plankton & fish communities. Cooper did not measure water transparency. Therefore (and unfortunately, given the ever-expanding base of Secchi data collected by LSM volunteers and others) it is not possible to explore how transparency in these lakes has changed over the 8 decades since these historical surveys were carried out.
Cooper et al. used gill and seine nets to collect fish. Supplemented by information from fish & game wardens, they thus documented the structure of the fish community in each surveyed lake (species composition, diets, age/growth). By comparing these data with more contemporary data from IF&W, it is possible to examine changes in lake fish communities over the past ~ 60 years. Especially interesting is the ‘spread’ of such species as largemouth and smallmouth bass as a result of both intentional and illegal stocking (and ‘natural’ range expansion).
Explore these changes in Maine’s lake fish communities HERE.
The Maine DEP Lakes Assessment Section works in a strong partnership with Lake Stewards of Maine/Volunteer Lake Monitoring Program (LSM) in the collection and management of water quality data collected from Lakes throughout Maine. LSM coordinates the initial gathering and quality assurance process for more than 1,300 individuals and many lake associations that monitor individual lakes across the state.
Also included in this undertaking are a number of regional entities, including Lakes Environmental Association, Cobbossee Watershed District, Mid-Coast Conservancy, 30-Mile River Watershed, 7 Lakes Alliance, Belgrade Lakes Association, Acton Wakefield Watershed Alliance, Allagash Wilderness Waterway, Portland Water District, Auburn Water District, Acadia National Park, and Rangeley Lakes Heritage Trust. Included are the sovereign nations of the Passamaquoddy Tribe at Indian Township, and the Penobscot Indian Houlton Band of Maliseets.
Data have also been acquired from private consultants, such as FBE and Lake & Watershed RMA, as well as others collecting lake data as part of regulatory requirements. Additional data are acquired through the DIF&W and through cooperative projects with the University of Maine System, Bates, Colby and Unity Colleges, and County Soil and Water Conservation Districts. Field data are also collected by the Maine DEP Lakes Assessment Section under probability-based studies conducted within EPA Region I, and as part of the National Lakes Assessment Study being conducted by EPA Headquarters.
We apologize if your lake data-gathering organization has been accidentally omitted. Please let us know if that is the case. Additional types of data are also submitted to the Lakes of Maine website, including Annual Loon Count data gathered by volunteers through Maine Audubon Society, and a variety of lake and watershed information provided by The Nature Conservancy.
Click here to view current water quality conditions on a representative sample of Maine lakes during summer, or view which lakes have experienced ice-cover in the fall and ice-out in the spring.
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