HIGH RESOLUTION MAPPING OF COASTAL SITES TO MONITOR SEA-LEVEL RISE AND RISK ASSESSMENT

Both the Holocene and Historic period of human occupation and utilization of coastal environments in the Gulf of Maine reveal significant erosion and loss of archaeological sites and the geological matrix. Multi-component sites selected for high-resolution mapping focus on the Isles of Shoals and Casco Bay in southwestern Maine.

Unmanned aerial system (UAS, or drone) acquired high-resolution digital imagery was used to construct dense point clouds, ortho-mosaics, and digital elevation models (DEM) for many key sites within Maine’s coastal region. This imagery was then analyzed using geospatial software to quantitatively and qualitatively monitor site alterations with sub-meter to sub-centimeter accuracy and precision.

The mapping of these selected sites represents various geomorphological characteristics, such as bedrock configuration and sediment matrices, combined with site content and allows for more precise modeling for long-term monitoring of site loss from storm surge, hurricanes, and events such as the Northeast Storms.

Models based on the matrix, site content, and evolution allow the opportunity to develop mitigation plans for short and long-term preservation.

The selected sites have all undergone total station mapping and test excavations where stratigraphy and sediment matrix have been established. Artifactual and faunal remains have been systematically recovered as well as count and density by volume mapped spatially. This analysis of the geological and cultural samples allows specific focus on risk to portions of the site.

The combined high-resolution mapping in coordination with detailed archaeological documentation allows the public to participate in policy and preservation with groups like the Casco Bay Estuary Partnership and Maine Coast Heritage Trust.