BLUFF FEATURE EXTRACTION FOR THE GREAT LAKES SHORELINES

摘要

Bluff recession rates are one of the main components of sediment budgets for the Great Lakes region. To calculate bluff retreat rates and estimate sediment volume inputs, both modern and historical bluff locations must be derived and used in recession rate calculations. Bluff edge delineation has traditionally been a manual exercise that requires user interpretation of bluff features from aerial photography. The increasing availability of high resolution Light Detection and Ranging (lidar) data provides a unique opportunity to explore automated methods to extract bluff features. A new, automated, repeatable method for locating zones of bluff shoreline and tracking the bluff edge in lidar Digital Elevation Models (DEMs) provides a valuable alternative to manually delineating modern bluff locations, as it is faster and provides consistent, objective results. The new method identified 393 km of bluff shoreline on Lake Michigan, with an average height of 195m, and 70 km of bluff shoreline on the US side of Lake Huron with an average height of 190m. As new lidar data becomes available, the methods developed may be used to extract the next set of bluff features for analysis of bluff retreat rates.