The flora of the U.S. Sierra Nevada alpine zone is characterized by small, low growing, cushion and mat forming plants that can survive the harsh conditions in the high-altitude alpine zone above the timber line cite journal rp Wildflowers of the Eastern Sierra and adjoining M...
Association of Ice and River Channel Morphology Determined Using Ground-penetrating Radar in the Kuparuk River, Alaska
- Citation data:
Arctic, Antarctic, and Alpine Research, ISSN: 1523-0430, Vol: 37, Issue: 2, Page: 157-162
- Publication Year:
- Repository URL:
- https://scholarworks.boisestate.edu/geo_facpubs/47; https://works.bepress.com/james_mcnamara/15
- 10.1657/1523-0430(2005)037[0157:aoiarc]2.0.co;2; 10.1657/1523-0430(2005)037
- Environmental Science; Agricultural and Biological Sciences; Earth and Planetary Sciences; Earth Sciences; Geophysics and Seismology
We collected ground-penetrating radar data at 10 sites along the Kuparuk River and its main tributary, the Toolik River, to detect unfrozen water beneath river ice. We used 250 MHz and 500 MHz antennas to image both the ice-water interface and the river channel in late April 2001, when daily high temperatures were consistently below freezing and river ice had attained its maximum seasonal thickness. The presence of water below the river ice appears as a strong, horizontal reflection observed in the radar data and is confirmed by drill hole data. A downstream transition occurs from ice that is frozen to the bed, called bedfast ice, to ice that is floating on unfrozen water, called floating ice. This transition in ice type corresponds to a downstream change in channel size that was detected in previously conducted hydraulic geometry surveys of the Kuparuk River. We propose a conceptual model wherein the downstream transition from bedfast ice to floating ice is responsible for an observed step change in channel size due to enhanced bank erosion in large channels by floating ice. © 2005 Regents of the University of Colorado.