Spatial Distribution of Sediments in Southern High Plains Playa Wetlands.

Playa wetlands are unique geomorphic features on the Southern High Plains (SHP). Playa wetlands are important resources for both crop and livestock producers and many wildlife species. The more than 20,000 playa wetlands also serve as the major source of Ogallala aquifer recharge. The degree of sedimentation in playa wetlands is an important aspect of watershed management. Two commonly recognized processes responsible for soil erosion and sedimentation in the SHP are hydrological events and wind. In the SHP, Conservation Reserve Program (CRP) grasslands, rangeland and cultivated cropland watersheds dominate the outer-basin areas that surround playa wetlands. Sediment depth and total volume were characterized as being directly related to land-use and soil textural zone. By measuring the depth of sediments with respect to the original playa basin, a three-dimensional model can be created showing the original playa basin with and without sediments. Therefore, models can be used in determining how input size and amount effects sediment deposition. The objectives of this study are to (1) measure depth of sediments with respect to the original playa basin for cropland and grassland playa watersheds, (2) develop a comprehensive three-dimensional map of the original playa basin and spatial distribution of sediments, and (3) qualitatively compare input size and amount with deposition of sediment as a function of watershed management. Six playas (3 cropland and 3 rangeland) will be selected for research. Core samples will be taken from each playa and sediment depth will be recorded. Particle size distribution and soil color are the sediment identification methods. A comprehensive surface map, including sediment and original playa basin, will be created. In doing so, spatial distribution patterns of sediment, with respect to land use, can be compared. The spatial distribution of sediments provides feedback on current conservation techniques and could identify problematic zones in SHP playas.