Wednesday, June 6, 2007 - 4:00 PM
308

Effectiveness and Use of In-Stream Structures in River Restoration in North Carolina

Jerry Miller1, R. Craig Kochel2, and Mark Lord1. (1) Department of Geosciences and Natural Resources Management, Western Carolina University, Cullowhee, NC 28786, (2) Department of Geology, Bucknell University, Lewisburg, PA 17837

A database of stream restoration projects is being developed for North Carolina.  Of the more than 375 recorded projects, a majority use in-stream structures to limit channel incision, reduce bed and bank erosion, or improve habitat.  The widespread use of in-stream structures indicates that their integrity can provide insights into the physical performance of restoration designs.  To date, we have evaluated 545 in-stream structures at 26 sites across the State. Field surveys show that at about half of the examined sites, at least 25 % of the in-stream structures had sustained significant damage and were no longer performing their intended function.  Channels with high failure rates are associated with easily erodible bed and bank materials and/or high rates of bedload transport.  A preliminary review of design documents shows that project development rarely involved detailed geomorphic analyses beyond channel classification, and seldom analyzed sediment transport continuity through the restored reach.  The large number of sites exhibiting damaged structures within a few years of construction strongly suggests that more rigorous geomorphic and hydrological analyses are required to improve the performance of restoration projects in the State even though this will initially require more time, money, and trained personnel.

See more of Special Session - Stream Restoration: Tools for Prioritization, Design and Assessment II
See more of Special Sessions

See more of The NABS 55th Annual Meeting