COLD CLIMATE FLUVIAL PROCESSES: AN INTEGRATED STUDY OF THE COLVILLE RIVER, ALASKA

The Colville River is the largest river on the North Slope of Alaska, draining over 50,000 square kilometers. Temperate fluvial processes cannot be used as analogs for cold climate fluvial processes on the Colville River because of the role ice and permafrost play in the fluvial system and the timing of fluvial processes. During the winter, ice on the Colville River freezes to the bed of the channel, halting the flow of water and transport of sediment. Permafrost can cause both extreme stability and instability of the banks of the Colville River due to thermoerosional niching during spring flooding. The goal of this research is to better understand cold climate fluvial processes through the use of remote sensing.

Remote sensing is used to analyze the Colville River where the river channel changes from a braided pattern to a meandering one in order to study channel and bar morphology and lateral migration rates over the past 60 years. Multisensor data from Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) onboard the Landsat satellites, Synthetic Aperture Radar (SAR) and data in the fine beam mode of the RADARSAT satellite, and digital orthographic quadrangle (DOQ) photographs have been obtained through the Alaska Satellite Facility and Geophysical Institute at the University of Alaska, Fairbanks (UAF), for use in this study. In addition, aerial photographs and false-color near-infrared photos have been obtained through the Map Office at the Geophysical Institute, UAF. By analyzing these images, both long-term and seasonal changes in channel morphology, as well as channel bar and flat evolution, can be observed and mapped, and will be used to determine locations for field investigations.

Better understanding of present day cold climate fluvial processes and the role ice and permafrost play in the cold climate fluvial system will enhance our understanding of past cold climate fluvial systems and improve structural planning and development in cold climates in the future by providing a better understanding of bank stability, in-channel processes, and lateral migration rates of cold climate fluvial systems.