Assessment of active sand volumes at Rockaway Beach and Fire Island in New York and Seven Mile Island in New Jersey

Between 2018 and 2023, the U.S. Geological Survey assessed shoreface sediment availability at three Atlantic Coast barrier island study sites in support of a National Fish and Wildlife Foundation project entitled, “Monitoring Hurricane Sandy Beach and Marsh Resilience in New York and New Jersey.” The three study sites are Seven Mile Island, New Jersey, Rockaway Beach peninsula, New York, and Fire Island, N.Y. Previously interpreted geologic boundaries from shoreface geophysical surveys and data from repeat bathymetric surveys at each of the study sites were integrated to quantify the active sediment volume, or the volume of sediment that could contribute to beach and shoreline behavior over annual to decadal time scales. This report describes the methods used to calculate these volumes and the variability of active sediment volume for each survey at the three study sites. Our data show that when shoreface volumes account for varying alongshore extent of each study site, Seven Mile Island and Rockaway Beach peninsula have about 1.5 times the active sediment volume measured at Fire Island.