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

Combinations of vegetation and structure were applied to control strea mbank erosion along incised stream channels in northwest Mississippi. Eleven sites along seven channels with contributing drainage areas ran ging from 12-300 km(2) were used for testing. Tested configurations in cluded eroding banks protected by vegetation alone, vegetation with st ructural toe protection, vegetation planted on re-graded banks, and ve getation planted on regraded banks with toe protection. Monitoring con tinued for up to 10 years, and casual observation for up to 18 years. Sixteen woody and 13 nonwoody species were tested. Native woody specie s, particularly willow, appear to be best adapted to streambank enviro nments. 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 st abilized by grading or toe protection. Natural vegetation invaded plan ted and unplanted stable banks composed of fertile soils. Designs invo lving riprap toe protection in the form of a longitudinal dike and woo dy vegetation appeared to be most cost-effective. The exotic vine kudz u presents perhaps the greatest long-term obstacle to restoring stable , functional riparian zones along incised channels in our region.