CONTROL OF STREAMBANK EROSION DUE TO BED DEGRADATION WITH VEGETATION AND STRUCTURE1

Abstract

ABSTRACT: Combinations of vegetation and structure were applied to control streambank erosion along incised stream channels in northwest Mississippi. Eleven sites along seven channels with contributing drainage areas ranging from 12–300 km2 were used for testing. Tested configurations included eroding banks protected by vegetation alone, vegetation with structural toe protection, vegetation planted on re‐graded banks, and vegetation planted on regraded banks with toe protection. Monitoring continued for up to 10 years, and casual observation for up to 18 years. Sixteen woody and 13 nonwoody species were tested. Native woody species, particularly willow, appear to be best adapted to stream‐bank environments. Sericea lespedeza and Alamo switchgrass were the best nonwoody species tested. Vegetation succeeded in reaches where the bed was not degrading, competition from kudzu was absent, and bank slopes were stabilized by grading or toe protection. Natural vegetation invaded planted and unplanted stable banks composed of fertile soils. Designs involving riprap toe protection in the form of a longitudinal dike and woody vegetation appeared to be most cost‐effective. The exotic vine kudzu presents perhaps the greatest long‐term obstacle to restoring stable, functional riparian zones along incised channels in our region. (KEY TERMS: vegetation; streambank protection; bioengineering; stream restoration; channel incision; riparian zone.)