Saturday morning, Steve Handy revved up his backhoe and began digging a five-foot channel through the barrier beach that separates Edgartown Great Pond from the ocean. By the afternoon, the channel was open and water began rushing out through the incoming surf.

Opening the pond each year helps to maintain salinity for shellfish and eelgrass. It also flushes out the nitrogen that accumulates mostly from septic tanks and runoff in the 4,500-acre watershed.