ARS | Publication request: Spatial distribution and morphology of sediments in Texas Southern High Plains playa wetlands

Submitted to: Texas Water Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 12, 2012
Publication Date: April 1, 2012
Citation: Villarreal, C.J., Zartman, R., Hudnall, W., Gitz, D.C., Rainwater, K., Smith, L.M. 2012. Spatial distribution and morphology of sediments in Texas Southern High Plains playa wetlands. Texas Water Journal. 3(1):1-4.

Technical Abstract: Playas are depressional geomorphic features on the U.S. High Plains. About 20,000 Southern High Plains playa wet¬lands serve as runoff catchment basins, which are thought to be focal points of Ogallala aquifer recharge. Sediments in playas can alter biodiversity services, impede aquifer recharge, and increase evaporative water losses. The purpose of this study was to evalu¬ate the effects of watershed cultivation systems on post-cultural sediment deposition in 3 pairs of cropland/native grassland playas in Briscoe, Floyd, and Swisher counties of Texas. A hydraulic probe was used to collect soil cores to 2 m or to refusal depth at 25 possible locations in each playa. Particle size distribution and soil color effectively identified sediment additions to the playas. Soil color transitions with depth from very dark grayish brown (10YR 3/2) to very dark gray (10YR 3/1) were always found in crop¬land playas but not in grassland playas. Particle size distribution was more useful in identifying sediment distribution than type. Using a kriging model, sediment volume in each playa was calculated from sediment thicknesses at the sampling locations and from sediment thicknesses interpolated between sampling locations. Sediment volume was directly related to watershed land use with more accumulated sediment in cropped playas than in grassland playas. Erosion of cultivated watersheds near playas con¬tributes sediments that decrease playa depth and can result in increased evaporative water losses and decreased aquifer recharge.