Spatial Distribution and Morphology of Sediments in Texas Southern High Plains Playa Wetlands

Abstract

Abstract: Playa wetlands are depressional geomorphic features in the U.S. High Plains. The approximately 20,000 playa wetlands in the Southern High Plains serve as runoff catchment basins and are thought to serve as the foci for Ogallala aquifer recharge. Sediments in playas alter bio-diversity services, may impede aquifer recharge, and increase evaporative water loss. This study evaluated the influence of watershed cultivation system on sediment characteristics in six Texas playas (three cropland and three native grassland). Soil cores were collected by hydraulic probe to 2 m or refusal depth at 25 locations in each playa. Particle size distribution and soil color proved to be adequate to identify recent sediment additions to the playas. Soil color transition from very dark grayish brown (10YR 3/2) to very dark gray (10YR 3/1) was always present in cropland contrast with grassland playas. Particle size distribution was more useful for identifying sediment distribution than in sediment identification. Sediment volume was directly related to watershed land-use with grassland playas having less accumulated sediment than cropped playas.