Hard revetments and bulkheads can be an effective way to keep the ocean from undermining shoreline buildings. It's a common method — but it comes at a price. Government scientists say that hardened shorelines can pose a threat to aquatic life and coastal ecosystems. The Washington Post reported on the issue last month (see: "Scientists worry that the Chesapeake’s natural shoreline is turning into a wall," by Darryl Fears).

"Because of development along the bay and its rivers, vast swaths of soft shorelines have been turned into stone," the paper reported. "The spread of what scientists call 'the armored shore' is depriving young fish, crabs and other organisms of food and shelter. And it is yet another reason why life in the bay is disappearing, according to new research funded by the National Oceanic and Atmospheric Administration."

Coastal bays and the rivers and streams that feed them are a critical nursery for ocean life. Noted the Post: "The bay estuary contains dozens of micro-estuaries in rivers and creeks that serve as nurseries for hundreds of animals, including fish that start out tiny and hide in grasses before growing and venturing out into the Atlantic Ocean. The bay is key to the health of marine life all along the Atlantic shore."

The Baltimore Sun covers the NOAA research here (see: "Scientists find 'armored' shoreline hinders bay grasses, crabs," by Timothy B. Wheeler). "Waterfront property owners all around the Chesapeake Bay have bulkheaded and riprapped their shoreline to protect it from erosion," the paper reported. "It's their legal right to keep their land from washing away, and over the years a growing share of the water's edge has been 'armored' with low wooden walls or large rocks. But a six-year, federally funded research effort is finding that the bay's increasingly hardened shoreline could be hindering the estuary's recovery from decades of pollution. It may be limiting where crabs, fish and terrapins can find food and shelter. It also may be aiding the rapid spread of an invasive marsh grass and helping to sustain the population of stinging nettles, a summertime nuisance for swimmers."

"Waterfront property owners must apply to local and state governments for permits to protect their shoreline," the Sun noted. "Since 2008, state law has required construction of so-called 'living shorelines,' which often involve planting marsh grasses, and building up the shore with sand and other natural materials. At least some living shoreline projects involve building a low sill of rocks at water's edge or even just offshore. Those projects appear to be less harmful to grass beds, scientists say, than bulkheads or revetments. But they said they didn't study the new shoreline structures enough to draw conclusions.

For more information on living shorelines, see the NOAA web page, "Living Shoreline Planning and Implementation."