HR: 1340h
AN: C13B-0274    [Abstracts]
TI: Preliminary field investigations and findings of thermokarst evolution and sediment transport in a sub-arctic watershed
AU: * Kodial, P S
EM: ftpsk@uaf.edu
AF: Department of Civil and Environmental Engineering Department, University of Alaska Fairbanks, PO BOX 755900, Fairbanks, AK 99775 United States
AU: Toniolo, H A
EM: ffhat@uaf.edu
AF: Water and Environmental Research Center, University of Alaska Fairbanks, PO BOX 755860, Fairbanks, AK 99775 United States
AU: Hinzman, L D
EM: ffldh@uaf.edu
AF: Water and Environmental Research Center, University of Alaska Fairbanks, PO BOX 755860, Fairbanks, AK 99775 United States
AU: Yoshikawa, K
EM: ffky@uaf.edu
AF: Water and Environmental Research Center, University of Alaska Fairbanks, PO BOX 755860, Fairbanks, AK 99775 United States
AB: The rapid thermokarst development in the Caribou Poker Creeks Research Watershed is a relatively new feature in this predominantly discontinuous permafrost region. The thermokarst was initiated by permafrost degradation and precipitated primarily by the rain event that occurred in July 2003. Initial results of a field study on the thermokarst evolution and sediment transport are presented here. The rapid morphologic changes have been observed by comparing topographical surveys carried out during two consecutive summer seasons. Groundwater flow from ground ice thaw coupled with summer precipitation has led to an enormous amount of sediment being transported from the upstream end of the thermokarst to a considerable distance downstream of the site. However, liquid discharge measurements at the input and downstream locations show a loss in the discharge, suggesting a complex network for the transport of water and sediment within the active layer. Preliminary data on suspended sediment concentration indicate that higher sediment transport occurs during and after rainfall events with infilling of the thermokarst by sedimentation to a depth of 18 inches in the downstream reaches. The high sediment transport is a clear indication that erosion of the area is an active and ongoing process. It shows the extreme sensitivity of permafrost to climate induced surface modifications.
DE: 3322 Land/atmosphere interactions
DE: 3344 Paleoclimatology
DE: 1823 Frozen ground
DE: 1863 Snow and ice (1827)
DE: 1615 Biogeochemical processes (4805)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting