Mapping Playa Lake Basins on the Llano Estacado, Texas

Texas Tech University

Conservation

Digital Elevation Model for Hale County

Hale County Dem With Filled Sinks

Map of Playa Basins Derived by Subtracting the Original Dem From the Dem With Filled Sinks

Soils Map (SSURGO) for Hale County Showing the Location of the Randall Clay Commonly Found at the Bottom of Playa Lakes

The Distribution of Randall Clay Extracted from the SSURGO Soils Data

Overlay Showing the Spatial Correlation Between the Randall Clay (Derived From the SSURGIC Data) and the Playa Basins (Derived From the DEMs)

Distribution of Playa Lakes in West Texas Based Upon the Occurrence of Randall Clay

Lubbock, Texas, USA

By Ernest Fish and Kevin Mulligan

Contact: Kevin Mulligan; kevin.mulligan@ttu.edu
Software: ArcInfo 8.3
Hardware: Dell workstation
Printer: HP Designjet 800ps
Data Source(s): Esri, National Elevation Dataset, and internal sources

The Llano Estacado is a relatively flat tableland located on the southern High Plains in west Texas. The region is unique insofar as the landscape is characterized by thousands of ephemeral playa lakes and few streams.

Understanding the spatial distribution and size of playa basins is extremely important in this semiarid landscape. The playas provide a water source and critical habitat for local wildlife and migratory birds, and the thousands of playa lakes serve as groundwater recharge basins for the southern Ogallala aquifer.

To map the distribution of playa basins, the Fill Sinks function of Arc Hydro was used to fill the depressions in the digital elevation model (DEM) for Hale County. The original DEM was then subtracted from the new DEM with the filled sinks. Where no depressions exist, the grid cells subtract to zero. Where depressions occur, the grid cells map the extent, depth, and volume of the playa basin.

Conservation Maps

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