|
|
||
 CHAPTER 1
INTRODUCTION
One of the most challenging problems of environmental hazard management faced in
the United States today is the stabilization of eroding streambanks. The U.S. Army Corps
of Engineers estimated that in 1981, of the 3.5 million stream-miles of channel in the United
States, approximately 575,000 bank-miles were eroding. This erosion results in serious
economic losses of private and public lands, disrupts transportation infrastructure (bridges,
pipelines, railroad lines, etc.), and degrades water quality. The sediments that are eroded from
these channels are deposited downstream in flood control and navigation channels, and in
valuable wetland areas. Consequently, streambank erosion is not simply a local problem which
only affects a few landowners, but rather, produces system-wide economic and environmental
consequences that affects all taxpayers.
Over the past several years there has been a growing interest in the development of
low-cost, environmentally friendly bank protection techniques, that are suitable for
landowners, local governments and other groups with limited resources. Many of these
techniques have been quite successful, while others have not performed as intended. At the
other end of the spectrum is reliance solely on complete riprap paving when another, less
costly, and perhaps more environmentally acceptable technique would be just as effective.
Unfortunately, many designers, after having success with a particular protection technique,
make the mistake of trying to apply this single method to all situations, regardless of the site
conditions. This often results in an ineffective design leading to structure failure. Even if the
appropriate protection technique is selected, failure may still occur if proper design
procedures are not followed. However, there is no published, definitive guidance or criteria
that addresses the suitability and effectiveness of the various bank stabilization techniques for
varying site conditions and project constraints. This manual provides the necessary guidance
for making intelligent decisions when selecting and designing streambank protection measures
or deciding not to install bank protection.
1
|
||
|
||
