Fighting the tide at the Merrimack’s mouth
The challenges facing the Merrimack River are changing as we see more impacts from climate change, and right now the hotspot for dramatic change is at the river’s mouth.
Over the past week, the river mouth was hit by two Nor’Easters, one of which lasted unusually long, slamming the beach during 8 astronomically high tides. The result — long stretches of Plum Island’s protective dune along the Merrimack River’s southern shore were wiped out, causing waves to wash over and flood many properties. With that dune gone, dozens of homes along the northernmost end of Plum Island may be imperiled if another powerful Nor’Easter hits the coast. The island also suffered temporary shutdowns of its water and sewer systems.
That’s not the only crisis facing the region around the river’s mouth.
The three-mile-long dune that protects Salisbury Beach suffered significant erosion, with some homes now sitting on or near the edge of sand cliffs. Protective dunes and seagrass plantings that had been built in the past few years were wholly wiped out. The sea also overwashed the dune, spreading sand, water and debris inland over 100 yards in some areas. Upriver near the Route 1 bridge, substantial flooding occurred in neighborhoods that border the Merrimack. That flooding was caused by rising ocean levels and a heavy flow of water coming down the Merrimack.
Back out on Plum Island, another unusual phenomenon has occurred — the rising seawater has forced the raising of a natural freshwater “lens” that sits just below the ground. The result is startling to long term residents. Ponds are forming in low-lying areas, and some homes are experiencing damage due to foundation shifting. One homeowner described how his century-old house is — for the first time — shifting and showing signs of structural damage, due to water rising from underground, which is twisting its foundation.
“On Plum Island, this kind of flooding has never been seen before,” said Newburyport Mayor Donna Holaday.
On Friday, the Merrimack River Beach Alliance — a coalition of local, state and federal officials, as well as local residents — met in an emergency session to discuss ways to save the homes along the Merrimack River shoreline on Plum Island. (The Merrimack River Watershed Council regularly attends these meetings to keep up to date on issues facing the Merrimack).
While many residents at the meeting insisted on immediate fixes, obstacles stand in the path. State and federal regulations prohibit the wholesale movement of sand from nearby areas where sand is collecting. Also, in 3 weeks work on the beach will largely be prohibited due to federal laws intended to protect piping plover hatching areas. A number of proposals by residents — such as “armoring” the beach by creating a massive wall made of boulders and implanting old Christmas trees into the dune to act as sand collectors — were discussed.
After two hours of deliberation, the Alliance decided it would push state officials to expand an “unprecedented” permit that the Department of Environmental protection issued yesterday. That permit allows property owners to repair dune damage that was done by last weekend’s storm. The Alliance hopes to get permission to build a 1,000-foot-long sand berm along the bank of the Merrimack River. The berm would be about 6 feet high, and would be intended to temporarily hold back the sea. The sand would be trucked in from offsite, per the state permit. Some estimated the berm might last for one storm. Cost was estimated at $175,000 to $200,000.
Longer term solutions are also being considered,. state Sen. Kathleen O’Connor Ives, D-Newburyport, suggested that a “hybrid solution” to erosion control be pursued. She suggested that the remedies used in other vulnerable areas be looked at.
“Not boulders, not a wall, but something with some surface area,” she said. “We need something more than dumping our money into sand.”