The Edgartown Great Pond summer cut can be declared a success!
An elevation graph depicting the entire lifespan of the 11 day cut
EGP was cut open to the Atlantic Ocean on Saturday July 20, 2024 and remained open until July 31, 2024 . We reached the 9-11 days of tidal flush and both water chemistry and biology are showing improvement!
Regular exchanges of water between the ocean and the Great Pond keep it healthy and teeming with life. We are grateful for the continued efforts of the Town to preserve and protect Edgartown Great Pond!
Pond openings serve 4 essential functions:
1. To flush the nitrogen and phosphorus built up in the pond via a pond-wide exchange of seawater.
2. To increase the salinity pond-wide in order to protect the eelgrass ecosystems.
3. To lower the elevation of the pond to avoid flooding.
4. To allow the exchange of biological organisms.
Mid-depth salinity (white box) is shown in parts per thousand (ppt), with the change after the cut indicated in blue. Good pond flushes cause salinity to increase pond-wide 8-12 ppt
Bottom salinity (ppt) before and after the summer cut. Good pond flushes cause salinity to increase pond-wide 8-12 ppt.
EGP is a living ecosystem that depends on regular and effective seawater flushes for its survival. When the pond is open to the ocean, cool, clean, and salty seawater infuses EGP with salt. Salinity is a measure of the amount of salt dissolved in the water. Higher salinities allow oysters and eelgrass to thrive, which strengthens the Pond’s ecosystem.
Photo courtesy of Owen Porterfield of the cut taken the morning of August 2nd (fully closed)
