Coastal Sediment Availability and Flux (CSAF)

Scientists collected sand auger cores from Fire Island to help reconstruct the evolution of the barrier over the last several centuries, with the goal of quantifying changes in sediment input and partitioning through time (e.g., how sand is distributed between the terrestrial portion of the barrier and the beach/shoreface).

Scientists collected sand auger cores from Fire Island to help reconstruct the evolution of the barrier over the last several centuries, with the goal of quantifying changes in sediment input and partitioning through time (e.g. how sand is distributed between the terrestrial portion of the barrier and the beach/shoreface).

Looking over the dunes towards the beach in the Otis Pike Fire Island High Dune Wilderness at Fire Island, New York. 

A geophysical instrument (chirp) is towed in the water (yellow instrument) from a floating sled to acquire information about the geology below the seafloor in Duck, NC as part of DUNEX. The USACE Field Research Facility can be seen in the background in the upper left corner.

USGS Research Geologist Jennifer Miselis will conduct shoreface geophysical surveys at the USACE Field Research Facility during DUNEX aboard the LARC, which is shown here being set up for the survey.

A groin at Seven Mile Island, New Jersey traps sand and contributes to widening of the barrier beach. This illustrates how human modification and wave processes shape the beach. In May 2021, Andrew Farmer, Chelsea Stalk, and Emily Wei conducted a multibeam bathymetry survey offshore of Seven Mile Island, along the southern coast of New Jersey.

Mendenhall postdoctoral fellow Daniel Ciarletta captured this view of the modern beach ridge system at Caladesi Island, along the Gulf coast of central Florida. Ciarletta and colleagues are studying the island as part of a project to explore barrier island response to long-term changes in sediment availability.

Dan Ciarletta (right) working alongside Julie Bernier (left) to collect a sediment core on Mullet Key, an island within Fort de Soto Park in Pinellas County, Florida. The core will be used to reconstruct the geologic history of the island.

Mendenhall postdoctoral fellow Daniel Ciarletta of the St.

Mendenhall postdoctoral fellow Daniel Ciarletta and geologists Julie Bernier and Nancy DeWitt of the St.

Mendenhall postdoctoral fellow Daniel Ciarletta and geologist Julie Bernier perform field reconnaissance at Caladesi Island, along the Gulf coast of central Florida. The scientists are refining a plan to sample and survey the island using sediment vibracores and ground-penetrating radar.

Cedar Island, Virginia is an uninhabited barrier that has migrated landward approximately 15-30 meters per year since 1984 due to its low sediment supply. The shoreface slope is gradual but almost entirely devoid of island sediment - both responses to its recent, rapid retreat. USGS scientists collect geologic and morphologic data from this island’s shoreface.

Fire Island, New York is sparsely populated and regularly nourished, but has few modifications that impede natural sediment exchanges. Shoreface geomorphology reflects past periods of seaward progradation and alongshore extension resulting in a relatively sediment-rich shoreface. USGS scientists collect geologic and morphologic data from this island’s shoreface.

Rockaway Beach, New York is heavily developed, has seawalls and groins and is regularly nourished. It hasn’t changed much over 20 years. The shoreface is steep and sediment cover doesn’t extend far from shore—likely the result of being fixed in place for decades. USGS scientists collect geologic and morphologic data from this island’s shoreface.

Animation displays modeled beach profile elevation as it has evolved at Fishing Point, Virginia. These data are based on historical charts and images and measure distance (in kilometers) of cross-shore accretion. Q_S is the flux of sand to the beach, and Q_D is the flux of sand from the beach to the active dune.

A scientist deploys a sound velocity cast from a boat while conducting a chirp geophysical survey offshore of the Rockaway Peninsula, New York. These geophysical data were used to quantify volumes of available shoreface sediment on this margin.

Fire Island is a barrier island off the coast of Long Island, New York that hosts several protected areas, nesting habitat for shorebirds, and beachgoers looking for a relaxing place for recreation. USGS studies how the island changes over time - in both the past and present - to better understand how the island may evolve in the future. 

USGS scientists use specialized equipment to measure sediment dynamics in nearshore and coastal systems. Access by boat is limited in these areas, so personal watercraft are equipped with GPS and echosounders to collect bathymetric data. Seismic sleds are pulled along transects from the beach across the water to measure changes in sediment type below the water.

Illustration shows the cross-section of a barrier island progressing from ocean (on the right) to marsh and then lagoon (on the left). 

Fire Island Lighthouse at Fire Island National Seashore

Eroded dunes on Fire Island, New York, nearly two years after Hurricane Sandy.