Put Sand Dunes on Plum Island’s New Beach
By Bill Sargent
I drove to Plum Island in early May to see how the Corps of Engineers’ new beach had fared in the April 30th storm. It has turned out that the beach replenishment has not turned out well. In less than a month, the beach had lost over a hundred feet of sand, almost a quarter of its area.
During the summer, erosion will slow down. But at its present recession rate, the new beach will only last one to four years. But the Corps needs four to six years to get permission to cut a weir into South Jetty to restore the natural flow of sand to the new beach. So Plum Island has to make it through a potential three-year plus gap in its protection.
Plum Island residents are like mayors planning for winter. They know snowstorms will likely happen, so they lease snowplows and stockpile sand and salt. If they don’t, they know their constituents will hold them responsible.
We know we will have more storms and erosion, so we should also stockpile sand. But we have the opportunity to kill two birds with one stone. We can bring in more sand and shape it into four parallel dunes, one dune for each expected year of erosion. The dunes absorb a wave’s energy and extend the new beach’s life. They will also act as stockpiles of sand available for serious erosion emergencies.
Where will this sand come from? There are several potential sources. The most readily available is sand that has filled in the Captain’s Lady’s parking lot. The owners, George, and Chris Charos, have kindly offered the sand to help their Plum Island neighbors.
The Massachusetts Department of Conservation and Recreation and the city of Newburyport have already applied for permission to add that sand to the beach. All the town would have to do is truck it a few hundred yards to the beach and shape it into dunes.
A second more expensive source of sand could come from land-based sand quarries in Maine. That sand formed sacrificial dunes in front of Reservation Terrace before the Pandemic.
The sand could also come from the million cubic yards of sand piled up on the ocean side of South Jetty. City workers could scrape the top three or four feet of sand off the top of the 30-foot-deep fillet, load it into city trucks and shape it into parallel dunes on the new beach. That fillet is what is called a dry sand borrow. It is an inexpensive, environmentally benign solution used successfully in other states and favorably viewed by
Will more beach grass be added? That would help with keeping the sand in place and help with dune formation? But maybe I am dreaming ….
Plant the beach grass into a grid 40” x 40” to keep a grip on the sand so it won’t easily blow away and hopefully help to retain the sand when the tide rises up to the dunes.
I know there is a lot of erosion of the sand dunes on Sandy Point Reservation beach, which is a shame, as the piping plover and other birds depend on these dunes for breeding. I believe that beachgrass should be planted into a 40” x 40” grid system on any new dunes or current dunes. To further prevent erosion of the dunes, I believe stainless steel mesh, similar to the mesh used by masons before applying cement, should be placed in front of the dune edge with small stones between it and the dune edge to stabilize the dune, so as to help hold it back from being washed away.