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EARSeL: 2nd Workshop on Remote Sensing of the Coastal Zone Porto, Portugal, 9-11 June 2005 |
SESSION PA2 COASTAL ZONE MANAGEMENT (cont.) |
Brian J. Moorman
Department of Geography and Department of Geology and Geophysics, University of Calgary
2500 University Drive NW, Calgary, Canada, T2N 1N4, CANADA
Phone: 403-220-4835 Fax: 403-282-6561
moorman@ucalgary.ca
Matthew Tait
Department of Geomatics Engineering, University of Calgary,
Calgary, Canada, T2N 1N4
Coastal areas in permafrost areas are especially susceptible to erosion due to the added thermal effect of the water on permafrost. To date, in most northern regions, this problem is simply an edge effect at the coastline. However, human induced coastal subsidence has the potential to dramatically enlarge the areas over which coastal degradation can occur.
With the planning natural gas exploitation in the Mackenzie Delta on the Beaufort Sea Coast in northern Canada, there is a requirement to monitor baseline subsidence and increased local subsidence associated with gas extraction. Some of the proposed gas fields are located in low-lying areas of the delta and it is anticipated that gas extraction will cause subsidence that could lower the ground surface below sea level. In addition the region is within the zone of continuous permafrost and there are extensive areas of excess ground ice, which upon melting will dramatically increase surface subsidence.
The remote location of the Mackenzie Delta poses many problems to the application of traditional surveying techniques in monitoring surface subsidence. It was determined that ground based surveys and DGPS would be ineffective for measuring the predicted rates of subsidence (in the order of 1 cm/yr). For this reason, usefulness of interferometric SAR for monitoring the inter-annual subsidence is being assessed. However, since the area is underlain by permafrost there is appreciable intra annual heave and settlement within the active layer.
To compensate for this seasonal movement, an active layer heave/settlement model has been created that enable the prediction of winter heave and summer settlement from limited site specific information and regional weather records. This enables the use of interferometric pair from different times of the year to study the long term subsidence rates.
The results of this research significantly advance our the potential for monitoring natural and human-induced changes to coastal areas that are in remote polar regions.
Last Update: 2005-03-16