The shapes and elevations of barrier islands can change dramatically during a storm. Between storms sediment is constantly shifting to and from these islands and among various depositional subenvironments. To investigate these changes coastal geologists have had to either settle for regional studies with sparse topographic data or small-area studies with more detailed data. With the advent of the Global Positioning System (GPS) and its incorporation into air, land, and sea surveying systems we are now able to map 10's of kilometers of coast in a day with unprecedented accuracy and detail.
We are applying the following five topographic/bathymetric surveying methods to monitor 150 km of the upper Texas coast (fig. 1): (1) airborne laser altimeter (also known as airborne LIDAR) surveys of the backbarrier, foredune, and upper beach with 15 cm accuracy and 2 m data spacing, (2) static and vehicular kinematic GPS surveys of the upper lower beach with horizontal and vertical accuracy of 2 cm, (3) eletronic total station surveys of selected transects from landward of the foredune into the surf zone, (4) nearshore GPS/echosounder surveys with 6-cm accuracy extending selected transects to approximately 7-m water depth, and (5) interferometric airborne synthetic aperture radar to rapidly acquire regional topographic coverage in the low relief coastal zone. These topographic data will allow us to develop a sediment budget for an entire barrier island system. We are also using the detailed topography to aid the interpretation and classification of optical and radar remote sensing imagery.
For more information, please contact Jeff Paine