Natural Products for Wetlands Erosion Control

Conventional engineering practices for erosion control are a common sight along our highways and waterways: carefully laid banks of barren angular stone called “rip-rap,” barriers of smaller stones encased in wire mesh called “gabions,” and poured concrete retaining walls. Bioengineering offers an earth-friendly alternative in many situations: carefully planned use of vegetation to satisfy engineering needs. Plants have been used for centuries, of course, to stabilize banks, but the approach lost favor during the past fifty years. The concept is coming back (armed with a high-tech name to impress people who need to be impressed) and is being used to stabilize steep embankments along highways, reduce erosion along rivers and streams, and protect ocean beaches.

Bioengineering approaches work with nature instead of against it. As a result, they have several important advantages over conventional practices: they are usually more permanent since natural vegetation takes over and does most of the work; they fit in better with the natural landscape; they are usually less expensive to construct; and, with wetland applications, they rely on natural biological processes to filter and purify water. Even the U.S. Army Corps of Engineers, long a bastion of over-engineered structures, seems open to the idea. “It has its place,” said Bernie Manor, chief of project operation at the Army Corps New England Division, referring to bioengineering. He said it works well for stabilizing a stream bank, but that “you can’t use it everywhere.”