Patterns and potential solutions to coastal geohazards at Golovin, Alaska
|Smith, Jacquelyn R.
|Thesis (M.S.) University of Alaska Fairbanks, 2014
|The objective of this research is to measure the localized potential for shoreline change and flooding on the Golovin spit, Alaska. Long-term trends of shoreline change have been measured using multi-temporal aerial photography and satellite imagery from 1972-2013, while seasonal and annual changes in shoreline geometry have been measured by re-surveying the beach in July 2012, July 2013, and October 2013. The local bathymetry was updated with data derived from the WorldView-2 satellite to increase the spatial resolution of nearshore topography. These inputs were then integrated to establish an XBeach 1-dimensional numerical model connecting offshore storm water elevations to nearshore dynamics. The spit was found to experience episodic erosion of beach sediments, followed by sediment accretion. This resulted in a dynamic position of the shoreline, with no long-term trend in either the offshore or landward directions. Modeled storms resulted in inundation of low elevations of the spit at a 5- year return interval, with inundation of infrastructure on a 25-year return interval. The modeled results suggest overwash of the entire spit at the 50-100-year return interval. All models were based on the best available forcing data from hindcast modeling. Reinforcing and increasing the elevation of a temporary berm and/or a permanent levee structure, using a 25-year return interval as a design parameter, would help to reduce localized flooding on the spit, and may be considered in the future.
|Patterns and potential solutions to coastal geohazards at Golovin, Alaska
|Department of Mining and Geological Engineering