Effects of Engineered Log Jams on Channel Morphology, Middle Fork of the John Day River, Oregon

• Main Author: Duffin, Jenna
• Other Authors: McDowell, Patricia
• Language: en_US
• Published: University of Oregon 2015
• Subjects: Engineered log jams; Fluvial; River restoration
• Online Access: http://hdl.handle.net/1794/19338

Engineered log jams (ELJs) were constructed on the Middle Fork of the John Day River in eastern Oregon as part of a large restoration project. These log structures were designed to address many of the restoration goals including creating scour pools, inhibiting bank erosion, creating and maintaining a sinuous river planform, and increasing complexity of fish habitat. This study uses geomorphic change detection techniques to monitor topographic change under and around the 26 log structures in two different river reaches over a six to seven year period. This study finds that the ELJs are remaining stable within the river and maintaining deep pool habitat. The study provides insight into which log structure variables are most related to the patterns and amounts of aggradation and degradation. Understanding the geomorphic changes to the riverbed in response to the placement of the ELJs can influence the design and future effectiveness of ELJs.