Paleo-landscape reconstruction and future predictions of impact of SLR and storm surges in Delaware Bay, USA.

Delaware Bay is one of the largest estuaries along the eastern coast of North America. The coastal geomorphology is controlled by modern processes and the ancestral landscape. Paleogeomorphology includes fluvial landforms of lower Delaware River valley that drained across the coastal plain to the edge of the continental shelf, Pleistocene dune fields and other periglacial features. The estuary has been developing since the early Holocene and continues to present due to relative sea level (RLS) caused by eustatic changes, isostasy, and local processes. Marine transgression inundated Delaware River converting ancestral drainage network into embayment and lagoons fringed by salt marshes. Associated with continued sea-level rise and widening of the estuary, increase in fetch caused the transition from tidal wetlands and mudflats to barrier beaches in the lower Delaware Bay. Paleo-environmental reconstructions document the coastal system response to natural changes should be considered in analysis of landscape response to climate change.

The Delaware Bay region has been occupied by humans since the Paleoindian period (~ 12,000-8,000 BP), was characterized as one of the most culturally diverse in colonial America and is today the location of several vibrant coastal communities.

Although some of the Paleoindian and later archaeological record has already been submerged due to SLR, numerous remaining cultural resources hold invaluable cultural resources and scientific information. Paleo-landscape reconstructions are critical to discover, document, and conserve buried archaeological sites as well as above ground historical resources.

Recent acceleration in the rate of sea-level rise is threatening the Delaware Bay coastal ecosystems, cultural resources, and living communities.

 

We used lidar and high-resolution drone imagery to map the modern coastal landscape, salt-marsh sediments as proxies for sea-level reconstructions, and stratigraphic relationships to reconstruct paleo-landscapes, and the chronology of abrupt or gradual environmental changes that impact coastal landscape. We used GIS-based paleo-landscape models to identify priority locations for systematic cultural resources survey and applied probabilistic SLR projections and SLOSH model to predict the impacts of future RSL and storm surges on the coastal landscape.