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ARS Home » Plains Area » Lubbock, Texas » Cropping Systems Research Laboratory » Wind Erosion and Water Conservation Research » Research » Publications at this Location » Publication #327977

Title: Comparison of Infiltration Flux in Playa Lakes in Grassland and Cropland Basins, Southern High Plains of Texas

item GEETHA, GANESAN - Texas Tech University
item RAINWATER, KEN - Texas Tech University
item Gitz, Dennis
item HALL, NICHOLAS - Texas Tech University
item ZARTMAN, RICHARD - Texas Tech University
item HUDNALL, WAYNE - Texas Tech University
item SMITH, LOREN - Oklahoma State University

Submitted to: Texas Water Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2015
Publication Date: 3/1/2016
Citation: Geetha, G., Rainwater, K., Gitz, D.C., Hall, N., Zartman, R., Hudnall, W., Smith, L. 2016. Comparison of Infiltration Flux in Playa Lakes in Grassland and Cropland Basins, Southern High Plains of Texas. Texas Water Journal. 7(1):25-39.

Interpretive Summary: Playas are shallow depressions that fill with water after heavy rains or long periods of rainfall. Afterward the shallow wetlands fill, the water either evaporates or seeps into the ground. Because the water "comes and goes" they are called "Ephemeral Lakes". Many scientists think playas are focal points for aquifer recharge. Others think that the clay soils under the playas seal the bottom and little if any aquifer recharge occurs. How much recharge actually occurs and how it is affected by land use is unknown. We observed how fast the water level in playas went down and compared it to how fast the water evaporated. The difference was how fast the water was lost through the bottom of the playa. We found that infiltration rates vary from playa to playa. Playas surrounded by cropland generally had greater infiltration rates than those surrounded by rangeland. We think this might be because of sand washing into the cropland playas, but more studies will need to be done to confirm this. Nevertheless, infiltration is clearly occuring through the playa lake bottoms.

Technical Abstract: Playas are the dominant wetland type on the Southern High Plains (SHP) of Texas and capture runoff during periods of heavy rainfall. Observing the hydrologic functions of playa wetlands is important to evaluate their ecological services, which include encouragement of species biodiversity and recharge of the underlying High Plains (Ogallala) aquifer. Ten pairs of playa wetlands, each with one surrounded by natural grassland and the other by cultivated cropland, were chosen in ten counties on the Texas SHP. Instrumentation at each playa allowed calculation of changes in free water evaporation and water stored over time. A water budget model calculated daily infiltration flux through the playa bottoms. Six cropland playas and three grassland playas had significant hydroperiods with associated consistent instrumentation operation during the five-year study. The average observed infiltration flux rates were approximately 10 mm/d (range 2 to 20 mm/d) and 3 mm/d (range 1 to 5 mm/d) for the cropland and grassland playas, respectively. The preliminary results may be influenced by the presence of eroded sediments from the surrounding cropland, but more events are needed to differentiate between the impacts of playa floor soils and variations in rainfall and playa watershed characteristics that contribute to the hydroperiods.