CHAPTER 6
RIVER STABILIZATION AND BANK PROTECTION
6.1 OVERVIEW
From a study of river morphology and river response (Chapter 5), it should be clear that both
short-term and long-term changes can be expected on river systems as a result of natural and
man-made influences. Recommended structures and design methods for river control are
presented in this chapter. The integrated and interactive effects of these structures with the
river are discussed in Chapter 9.
Numerous types of river control and bank stabilization devices have evolved through past
experience. Concrete, brick, willow, rock, and asphalt mattresses; sacked concrete and sand;
riprap grouted slope protection; sheet and timber piles; steel jack and brush jetties; angled and
sloped rock-filled, earth-filled, and timber dikes; automobile bodies; and concrete armor units
have all been used in the practice of training, restoring, and stabilizing rivers.
An early treatise on the subject of bank and shore protection was prepared by the California
Division of Highways (1959). A large number of publications on river training and stabilization
have been prepared by the U.S. Army Corps of Engineers (1981, 1994a,b) and the U.S.
Bureau of Reclamation. Many more publications on the subject exist in the open literature. It
is not intended that an exhaustive coverage of the various types of river control structures and
methods of design be made in this manual; rather, the purpose of this manual is to recommend
methods and devices which provide useful alternatives to the highway engineer for the majority
of circumstances which are likely to be encountered in highway practice. A treatise of great
interest in relation to highway crossings is the Report FHWA-RD-78-162 and 163 on
countermeasures for hydraulic problems at bridges by Brice and Blodgett (1978). The
interested reader is referred to these two volumes for an analysis and assessment (Vol. 1) and
283 case histories (Vol. 2).
The Federal Highway Administration has prepared Hydraulic Engineering Circular (HEC) No.
23 (Lagasse et al. 2001) to provide experience, selection, and design guidelines for a wide
range of stream instability and bridge scour countermeasures. When used in combination with
HEC-20 (Lagasse et al. 2001) and HEC-18 (Richardson and Davis 2001), these three
publications provide a comprehensive integrated approach to analyzing stream instability and
bridge scour problems and selecting and designing countermeasures for specific problems.
Generally, changes to river alignment, river cross section, training, and bank stabilization of
rivers associated with highway projects are confined to short reaches of the river. While the
methods for river training and bank stabilization discussed herein are applicable to short and
long reaches of the river, they are not a panacea to all problems associated with highway
encroachments on rivers. An understanding of river system dynamics is essential to selection,
design and successful installation of river stabilization, restoration, and bank protection works.
It must also be recognized that the solution to a particular problem may generate problems
elsewhere in the river system.
6.1
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