EGP Update

Photo courtesy of Cornelius Sullivan
Photo courtesy of Cornelius Sullivan

Most recent cut stats:

  • Cut opened March 10th, 2025
  • Cut closed March 18th, 2025
  • Tidal Exchange: 8 days
Graph illustrates EGP’s elevation and temperature from 3/9/2025-3/20/2025
EGP was opened to ocean on March 10th and was tidal for 8 days. This was a bit shy of the 9-11 ideal target. Tidal exchanges increase salinity and water clarity. The elevation on 3/10/25 was ~3.64 ft NAVD88 (4.02 ft LMSL). Following the 8 day cut the elevation dropped to 1.50 ft NAVD88 (1.88 ft LMSL) as of 3/20/25.
Following the EGP cut, salinity has increased throughout the pond. As of Thursday, March 27th Wintucket Cove and Lyles Bay had about a 10ppt increase, putting the salinity of the pond at about 19ppt. Eelgrass thrives in salinities 20 ppt or above. It becomes stressed below 15 ppt. If salinity drops to 10 ppt or less there is a likelihood of eelgrass loss. Ideally the post cut salinity target for the main body of the pond is 20-30 ppt with coves a bit fresher.

The spring salinity is important because it represents the conditions at the start of the growing season for life in the Pond (phytoplankton, seagrass, fish, shellfish). The higher the salinity, the better the health of the Pond and the organisms within it. If this is a wet spring, there is a chance another cut could be possible before peak summer.

⬇️Be sure to check out our EGP Cut Status page! We will update the page as cut data comes in. ⬇️

New URL: https://greatpondfoundation.org/egp/