by Kelly J. Klausmeyer, Agricultural Engineer
Natural Resources Conservation Service
Streambank erosion has been identified in Kansas as a serious concern, particularly upstream of reservoirs. Streambank erosion is an important source of the sediment and pollutants that enter area lakes, ponds, and stream channels. This article will discuss causes and a few of the solutions to streambank erosion problems.
The principal causes of streambank erosion may be classed as geologic, climatic, vegetative, and hydraulic. These causes may act independently, but normally work in an interrelated manner. Direct human activities, such as channel confinement or realignment and damage to or removal of vegetation, are major factors in streambank erosion.
Streambank erosion is a natural process that occurs when the forces exerted by flowing water exceed the resisting forces of bank materials and vegetation. Erosion occurs in many natural streams that have vegetated banks. However, land use changes or natural disturbances can cause the frequency and magnitude of water forces to increase. Loss of streamside vegetation can reduce resisting forces, thus streambanks become more susceptible to erosion. Channel realignment often increases stream power and may cause streambeds and banks to erode. In many cases streambed stabilization is a necessary prerequisite to the placement of streambank protection measures.
Protective measures for streambanks can be grouped into three categories: vegetative plantings, soil bioengineering systems, and structural measures. They are often used in combination. Conventional plantings of vegetation may be used alone for bank protection on small or intermittent streams, or in combination with structural measures in other situations. Soil bioengineering is a system of living plant materials used as structural components. Adapted types of woody vegetation (trees and shrubs) are installed in configurations that offer immediate soil protection and reinforcement. Structural measures include rock riprap, gabions, piling revetments and other relatively permanent measures to protect streambanks. The preferred method of streambank stabilization depends on site conditions, cost, and materials and labor availability.
For more information about streambank erosion, please contact your local Natural Resources Conservation Service office or conservation district office located at your local county USDA Service Center. To learn more about NRCS, visit the Kansas NRCS Web site at www.ks.nrcs.usda.gov.
This article is also available in Microsoft Word format.
Streambank Erosion (DOC; 53 KB)