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Savery Pond forms the headwaters of a creek informally known as Herring Brook, one of two fresh surface-water inputs to the Ellisville Marsh Estuary.  It has an area of 29 acres, average and maximum depths of 7 and 12.5 feet (respectively), and qualifies as a “Great Pond” as designated by the State of Massachusetts. The pond is spring-fed by local groundwater, with surrounding land uses including residential, forest, cranberry bogs and a commercial campground (primarily used by RVs). About 11 acres of commercial cranberry bogs operated on the pond for over 70 years, until recent changes in ownership converted one bog to a conservation area and the other to non-commercial status. People currently use the pond for fishing and recreation; however, Savery Pond provides key ecological functions and plays a significant role in the ecology of the Ellisville Watershed.

Savery Pond & Ellisville Marsh
Lilly pads on Savery Pond

Savery Pond has offered its human neighbors so much — the sight of osprey diving from aloft and turtles sunning on its shore, the sweet smells of flowers and leaves along the pond's vegetated fringe, the fun of swimming, paddling and fishing its waters — these terrific experiences were once taken for granted by pond residents and visitors. Today, inflows and accumulations of nutrients (phosphorus and nitrogen) have caused harmful algal blooms that impact both recreational uses and ecological functions. Specifically:

Algal Bloom on Savery Pond

Algal Bloom Clouding the Pond Water

  • Summer blooms of blue-green algae have led the MA Dept. of Health and Human Services to issue cyanobacteria advisories on Savery Pond in 2011, 2014, 2015, 2016 and 2017; and algal blooms have also been noted in other years. Cyanobacteria blooms contain toxins or other noxious chemicals that can pose harmful health risks. People or animals may develop skin irritation or upper respiratory problems from exposure to the blooms, and drinking associated pond water can cause kidney damage, liver damage and gastrointestinal symptoms (in extreme cases, dogs and other animals have even died after drinking pond water containing these toxins).

  • Decaying organic matter due to algal blooms reduces dissolved oxygen in pond water. This causes a ripple effect throughout the pond ecosystem that can impact fish and other organisms that need oxygen to survive, which in turn affects the birds, reptiles, amphibians, shellfish and mammals that use the pond. Conditions of extreme low dissolved oxygen can lead to fish kills. Periods of low oxygen can also change the minerals present and, over time, the natural chemistry of the pond.

Reversing harmful algal blooms and reduced dissolved oxygen conditions will require managing the nutrients that cause them. This webpage describes what we know about nutrient conditions in Savery Pond, what you can do to help, and the Ecology of Savery Pond. SPC’s goal of improving water quality in the pond will benefit the health of both the pond and Ellisville Marsh Estuary downstream. 

Please continue to visit this page to keep up with the latest developments and information related to the pond. 

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