RAPID: Continuous Measurement of Sediment Transport and Hydraulic Conditions in a Mountain Stream Prior to Wood Placement

Oregon State University, Corvallis OR

Investigators

Abstract

This project will study river bedload transport dynamics prior to and following placement of large woody debris (LWD) in the Siuslaw National Forest in the Oregon Coast Range. The team will instrument bedload with passive integrated transponder tags and track their movements prior to emplacement of the LWD. Recent news that no other such projects are currently scheduled or proposed in this National Forest, in addition to the accessibility of the site, creates urgency and opportunity to capture the pre-emplacement sediment dynamics under a range of conditions. The study will (a) provide fundamental, and rare, information regarding bed material sediment transport in field conditions, information that will serve as a valuable reference point for evaluating sediment transport relations based on flume and engineered-stream studies; (b) address the sensitivities of mountain stream sediment transport to downstream debris characteristics and upstream supply limitations; and (c) determine whether grain-size dependence of transport is accentuated or dampened by debris and other channel irregularities. This project will provide rarely obtained data that will inform not only theoretical understanding of sediment transport in mountain streams, but also stream restoration practitioners about the impacts of LWD placement. One application of LWD is for managing salmonid habitats. The team will interact with National Forest scientists and practitioners in the Pacific NW.