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Mean High Water Shorelines for the Outer Cape of Massachusetts from Nauset Inlet to Race Point (1998-2005)

September 22, 2020

This data release contains mean high water (MHW) shorelines for the Outer Cape of Cape Cod, Massachusetts, from Nauset Inlet to Race Point. From 1998-2005, the U.S. Geological Survey surveyed 45 kilometers of coastline 111 times using a ground-based system called Surveying Wide-Area Shorelines (SWASH). The SWASH system used a six-wheeled amphibious all-terrain vehicle as a platform for an array of Global Positioning System sensors. High-accuracy measurements of horizontal position, vertical position, and beach slope were collected at 0.5-second intervals as the vehicle traversed a single, shore-parallel line along the foreshore. The data were interpolated onto a coast-following reference line at 2-meter intervals. The shoreline position (defined as the intersection of the MHW datum with the foreshore) was determined by extrapolating from the location of the vehicle-driven track to the location of the MHW contour. The uncertainty for each shoreline point was calculated and the shoreline data were written to netCDF and ASCII csv files. This SWASH dataset represents a unique time series for quantifying large-scale coastal evolution, seasonal shoreline variability, and coastal behavior due to storms.