HR: 1340h
AN: GC33A-0962    [Abstracts]
TI: Digital Mapping of Coastal Erosion on the Baldwin Peninsula, NW Alaska: Past Rates, Present Processes and Future Implications
AU: * Olson, N F
EM: nfolson@gmail.com
AF: Idaho State University, 921 S 8th Ave, Stop 8072, Pocatello, ID 83209, United States
AU: Crosby, B T
EM: crosbenj@isu.edu
AF: Idaho State University, 921 S 8th Ave, Stop 8072, Pocatello, ID 83209, United States
AB: As Arctic temperatures warm and increase the period of ice-free seas, coasts are exposed to longer periods of wave-based erosion. In addition, warming accelerates permafrost degradation and thus decreases the mechanical stability of coastal bluffs. In this study we examine the Baldwin Peninsula which extends 108 km northwest into Kotzebue Sound but narrows to a neck less than 700 meters wide at its midpoint. Currently, water discharge and fish runs from Selawik and Kobuk Rivers are routed around the northern tip of the peninsula, adjacent to where the Noatak River enters the sea. The eventual breach of the narrowest part of the peninsula will result in drastic changes in fish passage, the morphology of the Noatak River delta and local economies dependent on subsistence and commercial fishing. To constrain past and present rates of bluff erosion, we completed a high resolution (~3 m spacing) topographic survey along ~5 km of the narrowest segment of the Baldwin Peninsula. The total station survey (georeferenced using GPS measurements at stations) defined the current bluff edge position on both the seaward and estuary side of the peninsula. In addition, the position of the bluff base was collected on the seaward side. Bluff retreat is accomplished by failure of adjoining arcuate-shaped thermal slumps. Seasonal wave erosion at the base of the bluff prevents slumps from ever stabilizing. To determine historical rates of retreat, we used geo-referenced historical aerial photographs from 1953 to the present processed in ArcGIS. Future surveys will determine if retreat is accelerating or maintaining current rates and identify if certain portions are retreating faster than others or if retreat is even along the coast.
DE: 0702 Permafrost (0475)
DE: 4217 Coastal processes
DE: 5415 Erosion and weathering
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting