Conference Papers

Geophysical surveys around the Chandeleur Islands provide the necessary data to map the thickness and distribution of the Holocene deposit associated with this barrier island system. This system rests uncomformably on St. Bernard Delta deposits of the Mississippi Delta plain and is thinnest under the central part of the island chain and thickest at the northern and southern ends. The...

Sixteen hurricanes have made landfall along the U.S. east and Gulf coasts over the past decade. For most of these storms, the USGS with our partners in NASA and the U.S. Army Corps of Engineers have flown before and after lidar missions to detect changes in beaches and dunes. The most dramatic changes occurred when the coasts were completely submerged in an inundation regime. Where this...

Recent research in the San Francisco, California, U.S.A., coastal region has identified the importance of the ebb tidal delta to coastal processes. A process-based numerical model is found to qualitatively reproduce the equilibrium size and shape of the delta. The ebb tidal delta itself has been contracting over the past century, and the numerical model is applied to investigate the...

The objective of this study was to provide a moderate resolution 30-m fractional water map of the Chenier Plain for 2003, 2006 and 2009 by using information contained in high-resolution satellite imagery of a subset of the study area. Indices and transforms pertaining to vegetation and water were created using the high-resolution imagery, and a threshold was applied to obtain a...

While most climate projections suggest that sea level may rise on the order of 0.5-1.0 m by 2100, it is not clear how fluid flow and sediment transport on fringing reefs might change in response to this rapid sea-level rise. Field observations and numerical modeling suggest that an increase in water depth on the order of 0.5-1.0 m on a fringing reef flat would result in larger...

The mechanism of sediment exchange between offshore sand ridges and the beach at Fire Island, New York is largely unknown. However, recent evidence from repeat nearshore bathymetry surveys, coupled with the complex but consistent bar morphology and patterns of shoreline change demonstrate that there is a feedback occurring between the regional geologic framework and modern processes...

A Delft3D-SWAN coupled flow and wave model was constructed for the San Francisco Bight with high-resolution at 7 km-long Ocean Beach, a high-energy beach located immediately south of the Golden Gate, the sole entrance to San Francisco Bay. The model was used to investigate tidal and wave-induced flows, basic forcing terms, and potential sediment transport in an area in the southern...

The series of Landsat missions has compiled the longest record of satellite observation of the Earth’s land surface, extending for more than 38 years for most areas of the globe. Landsat data are particularly important as long term climate data records because the scale of observation is sufficient to differentiate between natural and human drivers of land cover change. The USGS has...

Predictive equations were developed using stepbackward regression for 19 ecologically relevant streamflow characteristics grouped in five major classes (magnitude, ratio, frequency, variability, and date) for use in the Tennessee and Cumberland River watersheds. Basin characteristics explain 50 percent or more of the variation for 10 of the 19 equations. Independent variables identified...

Simulations using a modified regional groundwater- flow model were used to determine the amount of leakage from the Upper Floridan aquifer (UFA) through the Lower Floridan confining unit (LFC) into the Lower Floridan aquifer (LFA) resulting from pumping about 1 million gallons per day at newly constructed LFA production wells at Hunter Army Airfield and Fort Stewart in coastal Georgia...

To meet growing demands for water in the coastal Georgia area, the U.S. Geological Survey, in cooperation with the U.S. Department of the Army, conducted detailed site investigations and modeling studies at Hunter Army Airfield to assess the water-bearing potential of ponds and wells completed in the Lower Floridan aquifer.

In 2009, the U.S. Geological Survey initiated a study of saline aquifers in the southeastern United States to evaluate the potential use of brackish or saline water from the deeper portions of the Floridan aquifer system and the underlying Coastal Plain aquifer system (Fig. 1). The objective of this study is to improve the overall understanding of the available saline water resources for...