DIGITAL AERIAL CHARACTERIZATION OF GYPSUM KARST IN SOUTHWESTERN OKLAHOMA

Modern digital technology was used to identify and characterize gypsum karst features within an area of proposed energy development in the Permian Basin portion of southwestern Oklahoma. The remote assessment and processing of information at scales and high resolutions made it possible to assess and characterize a very large tract of land for planning and assessing feasibility of development. This project assessed the presence of karst features (sinkholes, closed depressions, etc.) in a site more than 18,000 hectares (70 square miles) within the Blaine Formation of southwestern Oklahoma. This was necessary to assess development risks associated with foundation and roadway construction, and long term subsidence/collapse risk for potential site development within the karstic gypsum formation. This presentation will describe the use of digital aerial imagery and digital modeling to identify surface depressions together with visual screening. The paper presents the selection of remote sensing methods, including a comparison of LIDAR, and digital imagery, as well as the methodogies used, including field verification. Ground truth was established by visual reconnaissance of representative areas on foot using GPS location of digital features. The ground truth assessment indicated the digital aerial mapping of gypsum karst features to be accurate to within centimeters. The paper presents the aerial and digital tools and methods used as well as the findings demonstrating an economical and highly accurate approach for assessing the presence of gypsum karst features within large tracts in the Permian Basin.