OutLook for the Bay – Last Words
The Shores are Alive
By Henry S. Parker
A quiet revolution is sweeping the Bay.
Not long ago coastal property owners sought to control erosion by armoring shorelines with hard structures that were unsightly, expensive and potentially harmful to the environment. Today the practice is to create “living shorelines,” vegetated buffers that dampen encroaching waves and create healthy habitats for aquatic life.
Wherever the land meets the sea, the ocean grazes on the coast, sometimes in nibbles, sometimes in large bites. This is especially true with the Chesapeake Bay, whose 12,000 miles of coastline are continually eroded by wave action, tidal currents, runoff from land and rising sea levels. In Maryland, nearly one-third of the shoreline experiences some erosion and every year the estuary claims some 260 acres of land—11 million cubic yards of sediment. Without intervention, waterfront homeowners and businesses could see their properties gobbled up. To protect against this, riparian residents have historically turned to firms specializing in the construction of rip-rap, breakwaters, groins and bulkheads made of stone, concrete and creosote-treated wood. But while temporarily stemming the sea, these structures often do more harm than good by discouraging and harming marine life. Sometimes they even increase coastal erosion by blocking the transport of naturally replenishing sediments. And they are costly — $500 to $1,200 per installed foot.
In contrast, living shorelines use indigenous plants and bioengineered materials like coconut-fiber logs to stabilize coastal areas. Ideally, a continuous cover of native vegetation is planted from the land just above the high tide level, through tidal wetlands, to intertidal areas that are submerged much of the time. Assuming a brackish water environment typical of Chesapeake Bay, appropriate species could include trees and bushes like eastern red cedar, red oak and bayberry on near-shore land; salt meadow hay, salt marsh hay, switchgrass and marsh hibiscus on tidal wetlands; and submerged aquatic vegetation like widgeon grass and eelgrass in intertidal areas. The roots of these species hold soils in place, reducing erosion. Their leaves and stems dampen wave energy and provide habitat for water fowl and marine animals, including commercial fish and shellfish and their larvae and juveniles. Living shorelines constitute dynamic, handsome vistas. They renew themselves instead of requiring ongoing maintenance and repair. And they don’t cost much—as little as one-tenth the price of armored shorelines.
So why would anyone even consider hard structures like breakwaters and seawalls, except in the most exposed, wave-lashed environments? Old habits die hard. As recently as the late 1980s, the state of Maryland initially opposed the construction of a pioneering living shoreline at Quiet Waters Park near Annapolis. But proponents prevailed, and other projects soon followed. When state officials checked after tropical storm Isabel in 2003, they found the living shorelines intact, but substantial damage to conventional hard structures. Five years later the state passed a law requiring that living shorelines be the preferred method of controlling coastal erosion. Virginia recently followed suit. Today Maryland issues about 1,000 permits a year for shoreline erosion control. Over 99 percent of these are for living shoreline projects.
The effort to replace old bulkheads and seawalls with living shorelines is a Bay-wide partnership among a host of public and private organizations. Partners have included federal and state agencies, the National Aquarium in Baltimore, the Chesapeake Bay Foundation, the Chesapeake Bay Trust, the Chesapeake Bay Maritime Museum, community associations, marine research and education organizations and schools and colleges. Even our favorite local team, the Baltimore Orioles have stepped up to the plate. In 2002 material from the demolition of the team’s Memorial Stadium was used to build an oyster reef as part of a living shoreline project at the Chesapeake Bay Environmental Center.
For residents of Chesapeake Bay, the potential erosion of valuable coastal land is always a concern. Fortunately property owners and community associations can now tap into a variety of assistance programs and resources, including financial assistance and grants, for living shoreline projects of their own. Interested? The following Chesapeake Bay Foundation website is an excellent place to start: http://www.cbf.org/livingshorelines
Henry, a former marine science instructor at the University of Massachusetts, is currently an adjunct associate professor at Georgetown University and a biodefense specialist. He can be reached at [email protected]
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