After decades of damage caused by erosion and pollution, Winthrop Beach, located northeast of Boston, Massachusetts, is in the midst of a major restoration project that will also provide environmental benefits for marshland 13 kilometers (eight miles) away.
Every day, 165 dump trucks are loaded with sand at the Rumney Marsh in Saugus, Massachusetts. The sand is then hauled south and deposited along a 1.6 kilometer (one-mile) stretch of the shoreline.
“The entire project will require 500,000 cubic yards [382,000 cubic meters] of sand, 350,000 of which are coming from Rumney Marsh in Saugus,” says Rachel Burckardt, Project Manager at Parsons Brinckerhoff. “The replenishment of Winthrop Beach will require a total of 22,000 truckloads before it is completed.” The remaining sand was dredged from areas near the Winthrop shoreline.
Parsons Brinckerhoff is the lead consultant for the design team, providing project management, civil and structural engineering, permitting, and construction management services for the Massachusetts Department of Conservation and Recreation (DCR). A.A. Will Corporation of Stoughton, Massachusetts is the construction contractor.
The total project will cost approximately $31 million. Improvements include construction of public beach access and amenities, repair of the protective seawall, and drainage and road repairs along Winthrop Shore Drive. At Rumney Marsh, improvements include construction of a linear walking path and pedestrian bridge.
Road improvements will begin next summer upon completion of the beach restoration. The entire project is targeted for a spring 2016 completion.
The project originated from the effort to clean up Boston Harbor in the early 1990s, building on improved water quality as a result of the Deer Island wastewater treatment plant to restore beaches and shorelines damaged by pollution and erosion. While most beaches in that region needed only minor aesthetic improvements, Winthrop Beach required extensive improvements.
“Winthrop Beach had severely eroded over the course of the 20th century,” Burckardt says. “Sediment that naturally replenishes the beach was lost, eventually undermining the seawall.”
Without sufficient beach between the ocean and the seawall, the beachfront neighborhood was at greater risk for frequent flooding. “There are times when the waves reach the buildings nearby,” she says. “By creating a gradual slope in the beach, the waves will break much sooner. Instead of slamming into the sea wall, the waves will roll up and just touch it, with most of the energy absorbed by the beach.”
There will be a natural loss of sand over time – perhaps as much as 10 percent in the first year – so periodic replenishment of the beach will be necessary. By having a “critical mass of material in the middle,” Burckardt says this project will minimize sand loss and keep the shoreline robust. “Ultimately, the ocean will shape the beach the way it wants, but we can make it as durable as possible.”
The initial plan to dredge all of the sand from offshore locations, a traditional shoreline restoration approach along US beaches from New Jersey to Florida, was approved by state officials but repeatedly rejected by the US Army Corps of Engineers, primarily over concerns about disruption of marine habitats, particularly associated with the endangered cod.
That prompted the possibility of transporting sand from Rumney March, an area also managed by the DCR. Sand was deposited on the marshland in the late 1960s as part of a planned interstate highway through the marsh. That project was abandoned in 1972, but only after millions of cubic yards of sand disrupted the marsh ecosystem. There was an ample supply of sand for the Winthrop Beach restoration.
Targeting Rumney Marsh as a source for the sand needed at Winthrop Beach created a “two-for-one” opportunity for the DCR. Not only did it eliminate the need to purchase additional sand for Winthrop Beach, but it would restore parts of the marsh to its pre-1970s state.
The removal of the invasive sand deposits will restore the marshland to some of its original characteristics, but the plan met with resistance from some Saugus residents who were concerned how it would look, and feared it would put them at greater risk for damage from natural disasters like Superstorm Sandy.
“We spent several months meeting with the Conservation Commission to review the best approach and address resident concerns,” Burckardt says. “The abandoned highway fill does provide some level of storm protection and acts as a noise barrier between the neighborhood and Route 107, so we are leaving some sand. She adds that the restored marsh will provide residents with better protection from flooding associated with rainstorms.
One concern conservationists expressed was over the impact sand placement might have on the nesting habitat for the piping plover, an endangered shorebird that has adopted Winthrop Beach as its habitat. Project Engineer Lisa Chandler says that through careful construction planning and preparation, bird and bulldozer have managed to successfully coexist.
“When we started, we were careful to stay the required 100 meters away from their habitat,” she says. “But some piping plovers eventually nested within 30 meters of our fences. People thought our trucks would scare the piping plovers away; instead, the birds moved closer to the worksite.”
Burckardt sees the Winthrop Beach project as an opportunity to create a benchmark for future beach restoration and renourishment throughout New England.
“It’s a more natural solution than just constructing a seawall or stone revetment,” she says. “Hopefully when this is completed, it will inspire others to take a similar approach to beach restoration.”