UMaine Researchers Question Saco Beach Erosion Measures
Contact: Laura Brothers (207) 581-1998; Joseph Kelley (207) 581-2162; Daniel Belknap (207) 581-2159; Tom Weber (207) 581-3777
ORONO — Researchers at the University of Maine have questioned the wisdom of a proposal by the U.S. Army Corps of Engineers to build a series of breakwaters near the shore of a Saco beach community to mitigate the serious erosion problems that have plagued homeowners there for decades.
The Army Corps plans to use a $27 million federal appropriation authorized by the Water Resource Development Act of 2007 for the construction of a spur jetty and two or more rock breakwaters near Camp Ellis, a community at the mouth of the Saco River that has lost 36 houses over the last 30 years to beach erosion.
Camp Ellis residents attribute the erosion to an extensive jetty system originally constructed by the Army Corps in the late 1800s, and modified around 1950, which inadvertantly funnels sand from the Saco River offshore into Saco Bay instead of allowing it to be deposited naturally along the community’s beach. The river supplies the sand for Saco Bay beaches as far north as Old Orchard Beach and Pine Point.
The aim of the proposed breakwater system is to protect Camp Ellis from ocean waves that threaten to carry its remaining precious sand from the beach and out to sea. Under the proposal, the Army Corps would also continue to dredge the Saco River every eight years and use that sand to replenish the Camp Ellis beach.
Yet in a paper published last week in the journal Marine Geology, UMaine researchers demonstrate that the Army Corps’s proposal underestimates the highly variable and multidirectional nature of sediment deposition common to Saco Bay.
“Our major concern with the proposal is that while the breakwater system might help Camp Ellis, it could hamper other sedimentary pathways and wind up causing erosion in other beach communities nearby,” says doctoral student Laura Brothers, who wrote the report with professors Joseph Kelley and Daniel Belknap of the Department of Earth Sciences.
Brothers also suggests it would be premature to move ahead with the proposal until more is known about the wave dynamics around the breakwaters, and whether the massive rock structures actually would keep the dredged river sand from escaping out to sea. The Maine Geological Survey also has concerns about how the sand might move after the proposed structures are in place.
“It’s very dangerous to put large piles of rock permanently on a beach,” Kelley says, “when we do not yet understand how sand moves along the beach and between the river and the beach. That is what they did when they put in the original jetty.”
Should Saco be required to sign on as a local partner for the project, Brothers adds, the city could wind up paying to haul in sand to replenish the Camp Ellis beach if the free dredged material continues to wash away despite the expensive rock barriers.
“We don’t believe this is the best solution for helping the people of Camp Ellis,” Brothers says. “It could wind up hurting other beach communities, maintenance costs could be a burden locally, and it still might not address the problem it’s supposed to address. What is needed at this point is a better understanding of the near-shore dynamics in this highly modified environment.”