What is the Largest Pond in the World?

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Oak Island in the largest pond in the world, Great Pond
Great Pond is home to several islands, including Oak Island, seen in this image. Tyler / CC BY-SA

The largest pond in the world is, unsurprisingly, called Great Pond. Located in Kennebec County, Maine, this pond is even home to several small islands! It’s an extraordinary site where freshwater from many streams and tributaries converge. Great Pond covers an area of 8533 acres (34.5 sq. km) and is located in the humble town of Belgrade. With a perimeter of 46.1 miles (74 km), this scenic pond is renowned for its stunning panoramas, and is a well-known site for exciting activities throughout the warm months.

With a maximum depth of 69 feet (21 meters), its waters are home to a diversity of flora and fauna, which in turn attract more wildlife. Approximately 7 miles (11 km) long and 4 miles (6 km) wide, the pond’s features entice fishermen and anglers throughout the country, along with adventurous families and nature-seekers all year round.

A typical summer day in this pond is nothing short of exciting, as canoes, kayaks, speedboats, jet skis, and happy campers populate the crystalline waters. However, as with many water systems across the world, anthropogenic activity has begun to threaten this pond’s natural ecology.

Interestingly, Great Pond has a rich history and was brought into being with the help of artificial means. A storage dam, which was constructed in 1886, was built to generate power in the area. This dam was instrumental in shaping the pond into its present form.


Why is Great Pond a Pond and Not a Lake?

Thermal stratification in lakes diagram
Lakes tend to have three distinct temperature layers. Great Pond is not considered a lake because it has fairly consistent temperatures throughout the water column. Mbrookings19, CC BY-SA 4.0, via Wikimedia Commons

For a body of water to be considered a pond, does it have to be smaller than a lake? Common sense tells us that the answer to this question should be yes, but truthfully the answer is more complicated. Though there are no criteria to legally differentiate between the two, the idea that larger bodies of water have to be considered lakes is a common misconception. In fact, the designation process involved in naming these bodies of water is still quite arbitrary. The Great Pond is actually considered the largest of the Belgrade Lakes, but limnologists (the technical term for freshwater scientists) argue that it is a pond because of its shallow depth.

With an average depth of just 21 feet (6.4 meters), the Great Pond is shallow enough for light to pierce through the entire water column and shine onto the bottom, making the entire pond a “photic zone”. This means that an underwater community of rooted plants would have access to sunlight for photosynthesis. Lakes, in contrast, tend to be hundreds of meters deep and usually only have rooted plants along the shoreline. Moreover, limnologists differentiate a lake from a pond by checking for thermal stratification. Though large, the Great Pond is likely to have fairly consistent temperatures throughout the water column. Lakes, on the other hand, tend to have three distinct layers: the warm layer on the surface, the cold “aphotic” layer that receives no sunlight, and a layer in between that rapidly changes in temperature.

Today, the terminology is used interchangeably and with reference to the size of a body of water. To dispel confusion, limnologists continue to come up with differentiating criteria which still focus largely on depth and thermal features.


Ecology & Wildlife in Great Pond

Milfoil plants in a pond
Invasive plants, such as these milfoil plants, have begun to disrupt ecosystem functions in Great Pond. Donald Hobern / CC BY-SA

Though relatively shallow, the Great Pond is a biodiverse water system that is populated by many economically important species. Fishermen flock to the area because this pond is home to several species of bass, trout, pike, perch, and even salmon. Unfortunately, it has recently grown vulnerable to invasive species that threaten the ecology of the pond. Invasive plants, such as milfoil, have begun to disrupt ecosystem functions. Removal efforts have been necessary to prevent the occurrence of dead zones. These occur as a result of the rapid growth of invasive plant species, which block out the sun and decrease oxygen levels.

Aside from aquatic plants, invasive amphibians have also begun to cause ecological disturbance. The mudpuppy, in particular, is a large water-bound salamander that is increasingly appearing throughout the Belgrade Lake System. Its rapid spread is a cause for concern as local biologists believe mudpuppies may be endangering some native populations of threatened species. Apart from invasive species, algal blooms linked to anthropogenic sources have wreaked havoc on the pond’s natural communities. Fortunately, researchers and residents around the lake are passionate and hopeful about protecting this beautiful pond. Restoration projects are underway and this great resource is continuously being monitored by experts in the field.


Protecting Natural Lakes & Ponds

Beaver in a body of water
Precious water bodies like Great Pond need to be protected, as the vegetation around them provides important habitats for riparian animals, such as this beaver. Becky Matsubara from El Sobrante, California, CC BY 2.0, via Wikimedia Commons

In response to their increasingly susceptible pond and lake systems, the Lakes Environmental Association (L.E.A.) of Maine, along with the Maine Department of Environmental Protection, have released guidelines on how to protect these precious water bodies. Their guidelines highlight the importance of shoreline landscaping, as vegetation can serve as a buffer to prevent excess nutrients from entering the lake via erosion or stormwater. Moreover, they emphasize that these buffer zones are important habitats for riparian animals, many of which are endangered species.  

Nutrient pollution is another challenge that compromises these fragile systems. Usually in the form of agriculture fertilizers, sewage, fossil fuels, and factory by-products, nutrient-rich substances can cause the uncontrolled growth of algae. This process is called eutrophication, and can result in dead zones in ponds and lakes. To combat this type of pollution, lakeside residents and infrastructure developers are encouraged to shun industrial fertilizers and adopt more organic measures of plant control. L.E.A. goes so far as to question whether a green lawn is really worth harming your neighboring pond or lake. A sustainable approach to caring for natural lakes and ponds is urged, as a self-sustaining water body has the potential to holistically benefit everyone.

Rebecca H
About the author

Rebecca H

Ambitiously passionate about conservation, eco-sustainability, and having new experiences and adventures! Alongside writing, I work as a Herpetological Technician, collecting and analyzing data about endangered reptile species. I'm also skilled with the proper identification of native and invasive flora and fauna, as well as habitat assessment/restoration of a variety of ecosystem types.

Read more about Pond Informer.

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