This study presents modern erosion rate measurements for a 100 km segment of the Beaufort Sea coastline based upon vertical aerial photography captured in 1955, 1979, and 2002. Annual erosion rates from 1955-2002 averaged 5.6 m a-1; however, erosion rates between 1955-1979 and 1979-2002 increased from 5.0 m a-1 to 6.2 m a-1, respectively. Furthermore, erosion rates increased at 60 percent (598), decreased at 31 percent (307), and changed less than +/- 30 cm at 9 percent (87) of the 992 sites analyzed between the two time periods. Additionally, historical observations and quantitative studies over the past 175 years allowed us to place our erosion rate measurements into a longer term context. Several of the coastal features along this stretch of coastline received western place names during the Dease and Simpson expedition in 1837 and the majority of the features had been lost by the early 1900's as a result of coastline erosion, suggesting that erosion has been active over at least the historical record. Incorporation of historic and modern observations also allowed us to detect the loss of cultural/historic sites as well as modern infrastructure. U.S. Geological Survey topographic maps reveal a number of known cultural/historical sites and modern infrastructure that date to at least the 1950's that were lost due to coastal erosion by the early 2000's. We were also able to identify sites that are currently being threatened by an encroaching coastline. Our modern erosion rate measurements can potentially be used to predict when a site or infrastructure will be impacted if such erosion rates persist. |
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