STREAMBANK EROSION ASSOCIATED WITH GRAZING PRACTICES IN THE HUMID REGION

Abstract

The effects of cattle grazing on stream stability have been well documented for the western portion of the U.S.,but are lacking for the east. Stream and riparian damage resulting from grazing can include alterations in watershedhydrology, changes to stream morphology, soil compaction and erosion, destruction of vegetation, and water qualityimpairments. However, few studies have examined the successes of best management practices (BMPs) for mitigating theseeffects. The objective of this project was to assess the ability of two common BMPs to reduce streambank erosion along acentral Kentucky stream. The project site consisted of two replications of three treatments: (1) an alternate water source anda fenced riparian area to exclude cattle from the stream except at a 3.7 m wide stream ford, (2) an alternate water source withfree stream access, and (3) free stream access without an alternate water source (i.e., control). Fifty permanent cross-sectionswere established throughout the project site. Each cross-section was surveyed monthly from April 2002 until November 2003.Results from the project indicated that the incorporation of an alternate water source and/or fenced riparian area did notsignificantly alter stream cross-sectional area over the treatment reaches. Rather than exhibiting a global effect, cattleactivity resulted in streambank erosion in localized areas. As for the riparian exclosures, changes in cross-sectional areavaried by location, indicating that localized site differences influenced the processes of aggradation and/or erosion. Hence,riparian recovery within the exclosures from pretreatment grazing practices may require decades, or even intervention(i.e., stream restoration), before a substantial reduction in streambank erosion is noted.