Stream restoration case studies in North Carolina utilizing natural channel design techniques
Many rural North Carolina streams are degraded due to historic channelization, dredging, and loss of riparian vegetation. The resulting incised channels have poor habitat and unstable bed features and streambanks. Stream restoration options for incised channels include constructing a new stable channel at the floodplain elevation, enhancing the floodplain at the existing channel elevation, or stabilizing streambanks in place. This paper describes three North Carolina stream projects completed since 2000 that make use of a variety of techniques to restore incised streams. Components of each project include channel geometry modification, in-stream structures, streambank stabilization, and riparian corridor restoration. Project objectives are to improve water quality and habitat, reduce streambank erosion, and enhance floodplain functions. The Stone Mountain project is a Priority 1 restoration in which an incised stream was relocated at a higher elevation on the adjacent floodplain. The South Fork Mitchell River project is a Priority 2 restoration in which channel geometry was modified at the existing elevation to create a new meandering stream with enhanced floodplain. The Mitchell River project is a Priority 3 restoration in which the floodplain of an incised straightened channel was widened and boulder structures were used to protect streambanks. The planning, design, construction, and monitoring of these projects are described along with lessons learned about effective restoration techniques.