James C. Gibeaut, Melba M. Crawford (Center for Space Research, The University of Texas at Austin), co-principal investigators; Roberto Gutierrez, Tiffany L. Hepner, Amy Neuenschwander, William A. White, Rebecca C. Smyth, John R. Andrews, and Thomas A. Tremblay

A highly detailed and accurate airborne topographic lidar survey was conducted over a low-lying, barrier island test site on the southwest end of Matagorda Island, Texas. The survey was conducted during a 3-day period and included five separate flights. A GPS ground reference station within the study area, data acquisition only during optimal GPS satellite conditions, surveying a calibration target each flight, overlapping flight lines, and careful postprocessing of the raw data resulted in vertical accuracy of 5 cm and an average data-point spacing of less than 1 m. The 20-km2 area is undeveloped and includes an open-ocean sandy beach, multiple dune lines, ridge and swale topography, back-barrier stabilized and active dune fields, relict recurved spits and tidal channels, and a large relict washover/flood tidal delta fan. A manual classification of depositional subenvironments using color infrared photography and field visits is being compared with the lidar DEM. Initial results show that the lidar DEM will significantly enhance environmental mapping of barrier islands. Hyperspectral data acquisition is anticipated next year.

This project is funded by a grant from the Army and Navy through the Center for Space Research of The University of Texas at Austin. The goal of the work is to develop applications of new remote sensing technology for the mapping of sandy barrier island coasts. The lidar program at The University of Texas at Austin is a leader in coastal applications of airborne topographic lidar.