Seagulls gathered on the shore of Grey Neck Beach in Harwich on a clear May afternoon. They were by the end of a large pipe that was spitting out a mixture of sand and water, but the occasional crab or worm got shot out too.
“Whoever says there’s no such thing as a free lunch hasn’t been to a dredge discharge,” said Ken Cirillo, the Director of the Barnstable County Dredge Program.
The pipe the gulls got their snacks from ran underwater for about half a mile before it connected to the dredge, a rectangular-shaped barge called the Sand-Shifter.
The dredge works in Harwich’s Allen Harbor every year so channels don’t shoal up. That’s a must for summertime on the Cape, according to local officials.
“The beaches and the waterways are the lifeline of Harwich. So being able to keep them open and safe, it’s critical,” Harwich Harbormaster John Rendon said.
The Barnstable County Dredge spends all fall, winter, and spring keeping channels clear for boaters and nourishing the beaches with sand so they’re ready for summer, making it essential to the Cape’s tourism economy.
Cirillo says it takes more than most people realize to make all that happen.
“Because most if not all of that work that we do is in the offseason… I don’t think many people know what we do.”
Hydraulic dredging consists of digging up sand, sucking it through a pipe, and spitting it out onto the beach.
For the first step, a piece of equipment called a cutterhead is lowered down into the water and breaks up sand. Cirillo said it’s like a giant eggbeater on the seafloor.
“As this big eggbeater turns, it has big blades on it… We’re going left to right, and we go back from right to left. So, we keep on going back and forth and we crab forward.”
The next task is to move the uprooted mixture of sand and water towards the beach with a pump.
“This is a very large impeller that’s spinning, so this is really what’s providing that suction,” Cirillo said.
The mixture that gets sucked up by the pump runs through a pipe along the barge’s deck. Then, the pipe runs towards the shore and shoots out the sand and water at whatever beach needs the material.
For the work near Allen Harbor, the pipe ran about 2,000 feet towards Grey Neck Beach.
Deckhand Andrew Dipietro was set up with a piece of machinery called a skid steer at the discharge site. He used it to grade the sand and level it off close to where the gulls were feasting.
“We’re renourishing the beach where there’s the most erosion. We’ll pump the sand where it’s needed most on the beach," Dipietro said.
Dredge Program director Cirillo said there has been more demand for dredging the last few years with climate change.
“So that is one of the direct results that we’re seeing, that this increased erosion that we’re seeing is coming from this incremental rise in the water level," said Cirillo.
Although demand is high, supplying the service isn’t easy. Strong winds and high seas can put work on hold.
Cirillo also said 14 of the Cape’s 15 towns use the Dredge’s services for their harbors and beaches, but a complex permitting process meant that just five of them could go ahead with projects in the last year.
“No towns had any projects ready to go in the fall, so we had a late start because of that.”
This past season, dredging services for Falmouth Inner Harbor cost around $8,000. In Chatham, dredging for Mill Creek, Aunt Lydia’s Cove, and Stage Harbor cost over $500,000 combined.
As erosion continues across the region, Cirillo and his team plan to keep clearing waterways, replenishing beaches, and keeping a few smart seagulls well-fed.
