The Freshwater Connection

SEPTEMBER 2022

Cape Cod’s 890 freshwater ponds and lakes occupy nearly 11,000 acres, or about 4% of the region’s total acreage. The land area that contributes to these freshwater resources, referred to as pond watersheds, is much larger and makes up nearly 20% of the total land area. As many pond watersheds have not yet been delineated, much more of the land on Cape Cod is directly connected to freshwater ponds.  

Cape Cod’s ponds and lakes are iconic visual elements of the landscape that play important ecological, habitat, and economic roles. A pond, as defined in the 2021 Pond and Lake Atlas, is a fresh, static, and permanent water body larger than 10,000 square feet.  

Geological processes dating back thousands of years formed the region’s ponds, most notably the Cape’s unique kettle ponds. From the air, these ponds may look like similar blue dots scattered across the landscape, but each pond is unique. The characteristics of Cape Cod’s ponds can vary widely, and information about individual pond characteristics is available in the Cape Cod Pond Atlas Viewer. 

Use the Cape Cod Pond Atlas Viewer to explore specific information on Cape Cod’s 890 ponds.

Cape Cod’s ponds range in size from less than an acre to 735 acres. The 20 largest ponds represent roughly half of the total acreage. The 356 ponds less than 1 acre in size represent 40% of ponds but only about 2% of the total pond acreage. 

A pond or lake with a surface water area of 10 acres or more (in its natural state) is called a Great Pond. Great Ponds are public resources, with State-protected rights to allow public fishing, fowling, and navigation below the low-water mark. Public access to Great Ponds is not guaranteed, but citizens may petition for such access where there is none.  

There are 132 listed Great Ponds according to the Massachusetts Department of Environmental Protection (MassDEP), and approximately 40 additional ponds which are not yet listed but meet the 10-acre criterion. All of these Great Ponds, listed and unlisted, make up 86% of the total pond acreage on Cape Cod.  

Despite there being 313 unique pond names, including some ponds that have multiple names, more than half (495) of Cape Cod’s ponds have no name at all. This may be due to the small size of many of the region’s ponds, lack of access, or other characteristics that may not attract the same level of interest or use as the Cape’s larger ponds.

Data on the depth of Cape Cod’s ponds is somewhat limited, but known depths range from a few feet to as deep as 88 feet. Cliff Pond in Brewster is the region’s deepest pond, and the ten deepest ponds are all over 60 feet deep. Over 40 ponds with known depths are considered shallow (less than 10 feet). The depth of a pond can influence mixing, water temperature, and nutrient cycling patterns.

The various unique characteristics of Cape Cod’s ponds influence how they may be affected by shoreline development, nutrient inputs, invasive species, and climate change – all factors that could lead to declining pond health. Examining the connection between pond characteristics and water quality will help identify patterns and trends that may inform strategies to protect, manage, and restore Cape Cod’s plentiful ponds.  The Freshwater Initiative aims to better characterize ponds, identify internal and external drivers of pond degradation, and improve and expand pond monitoring to provide consistent, up-to-date data to inform pond management strategies. 

Scroll through to discover data points for ponds in each Cape Cod town.