Edgartown Great Pond was opened to the Atlantic Ocean the Town of Edgartown on Monday April 4th, 2022. The pond drained and then remained tidal for about 24 hours. Per Edgartown Shellfish Constable, Rob Morrison, the official opening duration was 5 days.
The salinity of Edgartown Great Pond did not rise as a result of the the April pond cut. In fact, in some regions of the pond it the salinity decreased as a result of fresh groundwater entering the pond and the it drained to the ocean. Eelgrass prefers salinity >15 parts per thousand (ppt), so as the salinity continues to decrease, concern for the health of eelgrass grows.
Logger data from the MacKenty dock at the head of Wintucket captures the drop in salinity following the cut.
The elevation of Edgartown Great Pond continues to rise and is quickly approaching the minimum elevation threshold (>3.5 feet above sea level) needed to cut the pond. Shellfish Constable, Rob Morrison is keeping a close eye on the pond elevation and will make the cut as soon as both elevation, weather, and tide conditions allow, so as to preserve the eelgrass-dominant ecosystem. Eelgrass can be critically damaged if salinities reach <10ppt. The elevation of EGP as of May 27th, 2020 is approximately 3 feet above sea level.