Project Title: Controls on Sediment Transport in the Columbia River Basin
Mendenhall Fellow: Kelly Revenaugh MacGregor, (831) 459-1360 or (650) 329-4989, kmacgregor@usgs.gov
Duty Station: Menlo Park
Start Date: March 24, 2002
Education: Ph.D., Earth Sciences, University of California, Santa Cruz (2002)
Research Advisor: Guy Gelfenbaum, (650) 329-5483, ggelfenbaum@usgs.gov; David Rubin, (831) 459-3156, drubin@usgs.gov
Project Description: Significant erosion along the coastlines of southwestern Washington in the last decade has motivated increased studies of sediment sources, sinks, and transport dynamics in the Columbia River littoral cell. A key question is whether a reduction in sediment supply is responsible for the dramatic shift from a depositional regime. Because the Columbia River is the major fluvial system in the littoral cell, it is important to quantify sediment flux from the Columbia River into the marine environment. Determining changes in sediment delivery over time is critical for examining the role of sediment inputs in driving coastal change. In addition, monitoring grain size dynamics of transported sediment has important implications for both the health of riparian habitats and on the long-term impacts of dam installation and removal. Quantifying sediment inputs and transport in the Columbia River system is complicated not only by the size of the drainage, but by changes in climate, sea level rise, dam installation, and land use changes, all of which significantly affect sediment inputs and delivery to the coast. In addition, limited historical records of sediment flux in the system make extrapolation of existing data (over time and space) difficult. The goal of this research is to quantify sediment flux in the Columbia River over the last century, and to examine changes in sediment transport from one of the large tributary systems to the Columbia main stem. In particular, the comparison of sediment transport in dammed and unaltered reaches, and how this may affect transport as a result of long-term changes in grain size and flow dynamics is of high interest.
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