Abstract:
Research demonstrates that archaeological sites along the Oregon Coast are subject to the deleterious effects of earthquakes, landslides, tsunamis, aeolian processes, and coastal erosion. Preliminary survey and excavations of archaeological material at Bullards Beach State Park, Oregon have demonstrated that bank erosion along the Coquille River estuary poses a threat to archaeological sites in the area. There is an urgent need for resource assessment and damage mitigation to protect sites throughout the park before they are completely destroyed. This thesis uses Bullards Beach State Park as a case study to explore problems facing Oregon’s coastal archaeological resources, and to test aerial imagery data as a tool for estimating estuarine erosion rates. Aerial imagery dating between 1939 and 2016 was mapped in ArcGIS. By measuring the relative position of the riverbank in each set of images, it was possible to achieve estimates of erosion rates at Bullards Beach through the past eight decades. Results demonstrate annual erosion rates as high as 3.56 m/year at certain localities of the park, with an overall average of 1.44 m/year. These results may inform management efforts by tribal, state, and university groups working with archaeological material in the park.