Hilary Stockdon, Ph.D. (Former Employee)

Hydrologic connectivity of light detection and ranging (lidar)-derived elevation data is critical for coastal hydrologic modeling applications. However, unless hydrologically-enforced, raised structures (i.e. bridges, roads overlaying culverts) can block overland flow to coastal waters. Because highly detailed lidar-derived elevation surfaces include features such as bridge decks and road fill...

Most airborne topographic light detection and ranging (lidar) systems operate within the near-infrared spectrum. Laser pulses from these systems frequently are absorbed by water and do not generate reflected returns on water bodies in the resulting lidar point cloud. Thus, the absence of lidar returns over water is useful for identifying inland water bodies that are not connected by any path to...

Coastal shoreline mapping is a particularly complex issue because of the dynamic nature of water levels at the land-water interface, the various tidal vertical datums in use, and the spatial scale of the shoreline delineation. In addition, the definition of a shoreline varies depending on whether the shoreline will be used for nautical charts and navigation, delineating the legal federal and state...

The USGS Coastal National Elevation Database Applications Project organized a workshop in cooperation with the College of Staten Island-City University of New York to discuss storm surge modeling and get input from scientists across a broad community. The workshop, held on April 22-23, 2014 on the College of Staten Island campus, is part of a larger project intended to enhance topobathymetric...

Coastal topographic and bathymetric (topobathymetric) data with high spatial resolution (1-meter or better) and high vertical accuracy are needed to assess the vulnerability of Pacific Islands to climate change impacts, including sea-level rise. According to the Intergovernmental Panel on Climate Change reports, low-lying atolls in the Pacific Ocean are extremely vulnerable to king tide events...

The accuracy with which coastal topography has been mapped directly affects the reliability and usefulness of elevation-based sea-level rise vulnerability assessments. Recent research has shown that the qualities of the elevation data must be well understood to properly model potential impacts. The cumulative vertical uncertainty has contributions from elevation data error, water level data...

The Coastal National Elevation Database Applications Project supports scientific research and applications assessing restoration, redevelopment, and protection projects in the Hurricane Sandy impact areas along New Jersey and New York coastal beaches.

The U.S. Geological Survey (USGS) National Geospatial Program's 3D Elevation Program (3DEP) aims to collect new light detection and ranging (lidar) data over the same areas on an 8-year return cycle. Between lidar surveys, there may be significant differences in bare- and non-bare earth heights due to both natural and human-induced geomorphic changes that occur. Therefore, research methods are...

Scientific research and applications assessing coastal landscape change and vulnerability are critical for applications such as shoreline mapping, hydrodynamic modeling, coastal vulnerability, and coastal geomorphology studies. However, very little ground truth data are available within the intertidal zone and adjacent beaches.

Defining near-shore water depth (bathymetry) is problematic because ships cannot operate close to the shore while collecting acoustic bathymetric soundings. Alternatively, optical green laser lidar sensors have been used to collect bathymetric points, however, these types of lidar acquisitions are costly for the footprint collected and are subject to bathymetric inaccuracies in turbid water...

This image is a topobathymetric elevation model of a part of the Mississippi River in New Orleans, Louisiana, and is an example of inland bathymetry in the northern Gulf of America. This regional topobathymetric elevation model includes airborne light detection and ranging (lidar) point clouds, hydrographic surveys, side-scan sonar surveys, and multibeam surveys obtained from USGS, NOAA, the State...

This study explores the feasibility of using high-resolution digital elevation models (DEMs) constructed from airborne light detection and ranging (lidar) surveys to develop an automated procedure to extract levee longitudinal elevation profiles for both federal levees in Atchafalaya Basin and local levees in Lafourche Parish, south Louisiana. This approach can successfully accommodate abrupt...