2013-14 Massachusetts Lidar-Derived Dune Toe Point Data

This data release of dune metrics for the Massachusetts coast is part of a 2018 update to the Massachusetts Shoreline Change Project. Because of continued coastal population growth and the increased threat of coastal erosion, the Massachusetts Office of Coastal Zone Management (CZM) launched the Shoreline Change Project in 1989 to identify erosion-prone areas of the coast. Maps of historic shoreline locations from the mid-1800s to 1978 were produced from multiple data sources, and in 2001, a 1994 shoreline was added to enable the calculation of long- and short-term shoreline change rates. In 2013, the U.S. Geological Survey (USGS), in cooperation with CZM, delineated an additional oceanfront shoreline using 2007 topographic lidar data and 2008–9 color aerial orthoimagery. Further cooperation between CZM and the USGS resulted in this 2018 update, intended to increase the understanding of coastal erosion and to support coastal management decision making. This update includes beach shorelines, marsh shorelines, and dune metrics, all of which were derived from topographic lidar data. This data release, which is part of the 2018 update, defines the position and elevation of the most seaward dune crest and toe along the Massachusetts coast as derived from 2013–14 lidar data. In the absence of a dune, the peak of the berm or the seaward edge of a bluff, headland, or hard structure (for example, a seawall, road, or parking lot) was chosen as a proxy for the dune crest. Where possible, the dune toe was placed at the base of the proxy feature.