Coastal Landscape Change and Vulnerability
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.
During a field trip in late April, 2014,
U.S. Geological Survey (USGS)
National Oceanic and Atmospheric Administration National Geophysical Data Center
scientists collected precision elevation data at several locations in New York, including Heckscher State Park and Montauk Point State Park on Long Island; Dubos Point Wildlife Sanctuary in Queens, New York; Battery Park in Manhattan, New York; and along the southeastern coast of Staten Island, New York. At all locations, transects perpendicular to the shoreline were mapped using survey-grade GPS equipment to obtain beach elevation profiles. The field surveys were timed to occur near low tide, and the transects were extended into the water to a depth of up to 1 meter. The transect spacing varied based on the length of the publicly accessible shoreline, but the typical spacing was 50-100 meters. GPS elevation data were also collected in some forested areas and in densely vegetated wetlands, particularly in Phragmites australis
stands in order to quantify the accuracy of the bare earth elevation obtained from airborne lidar in various land cover types.
The goal of the field work was to collect field measurements using both precision GPS and a mobile terrestrial lidar scanner that is nearly concurrent with airborne lidar surveys that have been flown recently (winter/early spring 2014) over New York City. GPS and terrestrial lidar were collected along beaches, in adjacent coastal wetlands, in the intertidal zone, and along other topographic features such as seawalls or artificial dunes that can impede or direct the flow of water through the landscape. The data will be incorporated into an integrated topobathymetric elevation surface of the New York City area. A portion of the data will be set aside as an independent dataset to quantify the vertical error in the final integrated TBDEM and to evaluate the ability of airborne lidar to resolve small but important topographic features.
Survey sites for April, 2014 field work in New York and New Jersey to collect precision elevation data. U.S. Geological Survey (USGS) image created by Cindy Thatcher.
USGS scientists collect GPS topographic (land elevation) and bathymetric (water depth) data near Montauk, Long Island, New York. This beach was impacted by Hurricane Sandy. USGS photograph by Cindy Thatcher.
USGS scientists collect bathymetric (water depth) GPS data near Montauk, Long Island, New York. USGS photograph by Cindy Thatcher.
USGS crew members prepare for GPS and terrestrial lidar data collections, Staten Island, New York. USGS photograph by Sandra Poppenga.
USGS precision elevation and bathymetry data collected in April, 2014 on the southeastern coast of Staten Island, New York. USGS image created by Cindy Thatcher.
Terrestrial lidar was used to survey some of the new artificial dunes that have been installed since Hurricane Sandy along parts of the southeastern shore of Staten Island owned by New York City Parks. The south shore of Staten Island experienced severe flooding and erosion caused by storm surge during Hurricane Sandy. Beach elevation profiles spaced at 100 meters were collected along the Lower New York Bay shoreline on the south coast of Staten Island, including the Miller Field and Great Kills Units of Gateway National Park. USGS image created by Cindy Thatcher.
USGS scientist Jeff Danielson collects GPS data in a vulnerable coastal zone on Staten Island, New York. USGS photograph by Sandra Poppenga.