The Need for Sustained and Integrated High-Resolution Mapping of Dynamic Coastal Environments

Abstract

A B S T R A C TThe coastal zone of the United States is a dynamic environment evolving in response to both natural processes and human activities. In order to protect coastal populations and resources, a detailed understanding of the physical setting and of the processes responsible for change is required. A sustained program of mapping coastal areas provides a means to establish baseline conditions, document change, and, in conjunction with models of physical processes, predict future behavior. Recent advances in mapping technology, including airborne lidars and hyperspectral imagers, allow for the rapid collection of high-resolution elevation data and land use information on a national scale. These rich data sets are critical to evaluating risk associated with coastal hazards, such as flooding during extreme storms. For example, coastal elevation data is a fundamental parameter in storm surge models that predict where flooding will occur, and land use maps serve as the foundation of assessments that identify the resources and populations that are most vulnerable. A comprehensive, national coastal mapping plan that is designed to collect, manage, and distribute these data, as well as to take advantage of recent progress in mapping technology, will provide a wealth of information for studying the processes of physical change, for determining areas vulnerable to coastal hazards, and for protecting and managing our coastal communities and resources.

Water Level Observations for Storm Surge

“…This is due, in large part, to the effect of breaking waves, an effect that the SLOSH model does not compute. Also adding to this negative bias may be the erosion of barriers, such as sand dunes and roadways, due to the rising storm tide and breaking waves (e.g., Stockdon et al, 2007). Subsequent over-topping of these lowered barriers may lead to additional water in bays and sounds with resulting higher measured water marks.…”

“…For surge model evaluation, water level data must capture the highest point of the surge, free of wave influence, again relative to a consistent datum. All of the above presume that accurate land elevations and water depths also are available relative to the same vertical datum (Stockdon et al, 2007). Issues of differing vertical datums, water level gauge range and placement, data telemetry, and alternative methods of data collection are discussed.…”

Assessing debris flows using LIDAR differencing: 18 May 2005 Matata event, New Zealand

“…LIDAR technology has been applied in a number of scientific investigations to rapidly produce detailed topographic models which provide advancements in geomorphological and coastal research (Stockdon et al, 2007). LIDAR is an optical technique that uses the time taken for reflected light to return from objects or surfaces to determine the range, in a similar manner to radar.…”

Elevation Uncertainty in Coastal Inundation Hazard Assessments

“…Elevation data derived from lidar (light detection and ranging) remote sensing are often used in coastal areas because of their high vertical accuracy and high spatial resolution (Brock et al, 2002;Sallenger et al, 2003;Stockdon et al, 2007), but lidar measurements are sensitive to ground cover so in some cover types the lidar sensor may not detect ground level. This can lead to measured errors in an accuracy assessment that do not follow a normal distribution, thus the need for an alternative 95% confidence error metric.…”