Authors: Robert T. Pavlowsky, Missouri State University, Joseph Nash*, Missouri State University, Marc Owen, Missouri State University
Topics: Geomorphology, Hazards and Vulnerability, Earth Science
Keywords: River Restoration, Flooding, Bank Stabilization, Geomorphology
Session Type: Paper
Start / End Time: 2:40 PM / 4:20 PM
Room: Napoleon D1, Sheraton 3rd Floor
Presentation File: No File Uploaded
Engineered log structures (ELS) composed of local tree logs have been installed previously in river channels in the Pacific Northwest as a restoration technique. However, ELS have not been tested for use in the Ozark Highlands. In October 2016 the U.S. Forest Service installed ELS at four sites to stabilize banks along the North Fork of the White River in Ozark County, Missouri. The purpose here is to report on monitoring efforts during and after construction and to assess geomorphic responses to three floods. Over a ten day period in April 2017 there were two bank-full floods, and on April 30, 2017 the largest flood of record occurred with a stage of 42-45 ft above the channel bed. Post-flood assessments show: (i) two ELS sites were buried by several meters of bar sediment from widespread gravel splay deposition; (ii) fluvial wood pieces in the channel doubled from 101 pieces in 2016 (pre-flood) to 210 pieces in 2017 in the 700 m long study reach, (iii) at one ELS site, the thalweg moved to the opposite side of the channel during the flood; (iv) two ELS sites trapped fluvial wood and enhanced sedimentation along banks; and (v) cable tie-downs are needed to secure logs since burial anchoring is limited due to shallow bedrock typical for Ozark rivers. ELS practices offer benefits to improve channel stability and enhance habitat, but more work is needed to identify the most effective designs and locations for deployment.