Editor’s note: This is the first of two parts looking at current erosion on Plum Island and its parallels to erosion crises in the 1970s.
The clang of huge rocks dropping out of dumptrucks can be heard all over the north end of Plum Island these days.
It’s a welcome sound for many. It means gaps in the island’s 2,445-foot-long stone jetty are finally being fixed. And many believe that will help solve the erosion problems that have been sweeping away wide swaths of the beach some 2 miles to the south.
The same sound was heard a little more than four decades ago, when the jetty underwent a similar repair. But within a few years, an unexpected crisis occurred. Large chunks of Plum Island Point started to wash away, literally clawed out to sea by the powerful scouring action that the repaired jetties created in the mouth of the Merrimack River.
It reached its crisis point in late 1974. At a public meeting, authorities told horrified islanders that up to 80 homes at the northern tip could be lost. Desperate measures such as building massive sandbag walls and berms had failed; they simply washed away. After that meeting, Newburyport’s City Council took emergency actions, installing a wall of massive concrete blocks all along Reservation Terrace, a last line of defense for the homes on the other side of the street.
Today, the concrete blocks are still there, but the threatening and clawing sea isn’t lapping against them anymore. here’s a vast, healthy sand dune, perhaps 200 or more yards wide, between those blocks and the sea. Over time, Plum Island Point healed.
But as the rocks are gradually refitted into the jetty today and the holes are blocked up, islanders who have been watching the progress have been noticing some familiar signs. The shore of Plum Island that presses against the rivermouth is starting to erode again. The Army Corps of Engineers is watching, but thus far, it’s unclear whether the kind of extensive erosion the Point endured 40 years ago will happen again.