ASSESSMENT OF A HEAVILY MODIFIED COASTAL LANDSCAPE USING GEOPHYSICAL TOOLS

To mitigate saltwater flooding, the waterfront and downtown areas of Port Angeles Washington were filled with up to 8 m of anthropogenic fill during the winter of 1914. This activity buried several Native American sites, including one or more culturally sensitive burial grounds. To aid city planners and cultural resource managers in future development, predictive maps of the fill thickness were generated using a combination of: 1) field observations, where the thickness of the fill could be observed directly in the landscape, 2) topographic differences between pre-fill sounding maps and present-day LIDAR determined elevations, and 3) extensive ground penetrating radar (GPR) surveys. These geophysical surveys also helped to reconstruct the now buried paleo-environment by identifying tidal lagoons, beach berms and stream channels features beneath the fill layer. This knowledge of past landscapes is critical in developing archaeological predictive models. It also gives critical insight into the geology of the subsurface and its control on the flow of groundwater and modern contaminants.