QUANTIFYING RECENT MORPHOLOGIC CHANGE OF THE NAUSET BARRIER SYSTEM, CAPE COD, MA

Coastal environments are the most vulnerable to the impacts from changing climate especially regarding sea level rise. The Nauset barrier system is a high energy tidal lagoon located on the border of Eastham and Orleans, Cape Cod, MA. The Nauset system landscape has shown to be very dynamic over time, within the past half century the barrier system and inlet has experienced morphologic changes of the barrier location and overall volume at an increasing rate than previously observed.

High resolution aerial imagery dating back to 1938, historical maps dating back two centuries and LIght Detection and Ranging (Lidar) dating back to 1998 provides insight into the barrier island and inlet evolution over time. Barrier volume analysis has been conducted using Digital Elevation Models (DEMs) and comparing the volume of the barriers between lidar datasets. Documented trends in volume change over time provides evidence into the dramatic changes to the system and possible future configurations. Aerial imagery, Lidar and historical maps are used to identify inlet location over time as well as the rate of inlet migration.

The increase in the rate of change of the barriers since the mid-20^th century, specifically the inlet migration rate which increased from 0.44 m/yr prior to the mid-20^th century (1844-1952) to 11.08 m/yr since the mid-20^th century (1952-2021) indicate changes in the offshore environment from rising sea levels, increased storm activity and storm severity. The direction of the net sediment transport and inlet morphology are evidence of a shift of the nodal point to a location south of the Nauset barrier system as discussed in previous studies. Understanding the past and current morphologic changes of the coasts within small and large systems will give greater insight and potential planning strategies for coastal planner and managers.