Controlling Erosion Damage on Streambanks
Posted: October 18, 2011
In addition to determining damage to your buildings, trees, crops and access roads, you should also do an assessment of any major erosion problems caused by the storms and flooding. This is particularly important if you have a stream on your property.
Walk your property and note the extent of the damage on your maps or photos. Draw boundaries to help determine the size of the area impacted. Examine the banks of your streams for erosion damage. If you have any erosion control practices already in place such as riprap or gabions, check them for damage or any maintenance that may be needed. Stream blockages, eroded stream banks, and accumulated debris can present significant problems in the aftermath of a flood. The removal of debris and blockages from streams and any work to stabilize stream banks must be carefully planned.
Working in or near a stream, other than to remove floatable debris, requires permits from the Pennsylvania Department of Environmental Protection (DEP). Floatable debris that becomes lodged in critical areas of streams can be removed without permits provided that the work can be done without entering the flowing water with equipment. The use of cables and chains or backhoe arms to reach into the area and remove the debris is allowed. The DEP recently released a fact sheet called “Permitting Options for Flood-Damaged Bridges and Other Water Obstructions and Encroachments” which is available on-line at: http://www.elibrary.dep.state.pa.us/dsweb/Get/Document-85317/3800-FS-DEP4341.pdf. Contact your regional DEP office for additional information.
You can also contact your county conservation district to determine what permits are needed to do “in-stream” work. Your county conservation district may also be able to provide you technical assistance with planning and implementing streambank stabilization techniques. Another good source for information and assistance can be a local watershed association.
If you have streambanks that are severely eroded, you’ll need to stabilize the soil to promote plant growth. There are three general streambank stabilization approaches you might consider. They are live planting, bioengineering, and hard armoring. The best technique will depend on the size and location of your stream, and the cause and severity of the erosion. In many cases, the best approach is to use a combination of techniques.
You may be able to stabilize streambanks or prevent erosion problems by planting appropriate types of vegetation, then allowing nature to heal itself. A small investment of time and money can prevent a serious erosion problem that in the future could be very expensive to correct. Bioengineering relies on a combination of structural components and plant material to produce a dense stand of vegetation that serves as a “living system” to protect streambanks. Hard armoring includes a variety of techniques including rock riprap (large stones placed along the slope of a streambank) and gabions (rock-filled wire baskets placed along a streambank). Hard armoring typically involves grading the bank to a gentler slope. If done properly, these techniques provide very good protection and will work in severe situations where bioengineering will not. However, hard armoring techniques can be relatively expensive, and may require professional assistance.
Stabilizing stream banks can prevent the loss of land or damage to utilities, roads, buildings or other facilities adjacent to a watercourse. It helps prevent the loss of stream bank vegetation and can control unwanted meander of a river or stream. It can reduce sediment loads to streams and help maintain the capacity of the stream channel. Streambank stabilization can improve the stream for recreational use or as habitat for fish and wildlife. By controlling erosion through streambank stabilization, you can help protect the quality of the water that flows from your property.
George Hurd is the Penn State Cooperative Extension Environmental/Resource Development Educator serving the Southeast Region. Penn State Extension in Cumberland County is located at 310 Allen Road, Suite 601, Carlisle, PA 17013, phone 717-240-6500, e-mail Cumberlandext@psu.edu.
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