Stream Restoration Assessment of Abrams Creek in the Great Smoky Mountains National Park: Management Implications and Comparison of Empirical and Analytical Physical Assessment Approaches

Natural resource managers in the Great Smoky Mountains National Park requested the assistance of the University of Tennessee Department of Civil and Environmental Engineering to assess Abrams Creek for potential stream restoration needs. A presumed, unstable study reach and a stable reference reach were identified on Abrams Creek in Cades Cove. Chemical, biological and physical assessments were completed on Abrams Creek in order to evaluate ecological health and channel stability of the stream. Water quality and ecological (fish and habitat surveys) data acquired by National Park Service, Tennessee Valley Authority and the University of Tennessee were assessed. The physical assessment included two approaches; they were: 1) empirical or reference reach approach; and 2) analytical or non-reference reach approach. The current empirical technique used was the analog Natural Channel Design. The current analytical techniques were the hydraulic, sediment transport and erosion models (HEC-RAS, CONCEPTS). These physical assessment techniques were used to determine bankfull or effective flows, sedimentation, stream stability, and ecohydraulics. In addition to using these techniques for the Park’s management objectives, they were applied to both reaches for comparison in order to clarify areas where professional judgment may introduce uncertainty. From comprehensive physical assessments no system wide instabilities were observed but some riparian area differences and localized erosion were noted. Recommendations for potential restoration needs on Abrams Creek include localized stabilization of stream banks and vegetating the riparian corridor along the study reach.