Comparison of infiltration flux in playa lakes in grassland and cropland basins, Southern High Plains of Texas

Geetha Ganesan, Ken Rainwater, Dennis Gitz, Nicholas Hall, Richard Zartman, Wayne Hudnall, Loren Smith

Abstract


Playas are the dominant wetland type on the Southern High Plains  of Texas and capture runoff during periods of heavy rainfall. Observing the hydrologic functions of playa 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 playas were chosen in 10 counties on the Texas Southern High Plains. Each pair included 1 playa surrounded by natural grassland (not in the Natural Resources Conservation Service’s Conservation Reserve Program) and 1 playa surrounded by cultivated cropland. Instrumentation at each playa allowed calculation of changes in free water evaporation and water stored over time during the hydroperiods, defined as continuous durations of surface water storage in the playa basins, caused by one or more rainfall events that generated sufficient runoff flows to reach and fill the playas. A water budget model calculated daily infiltration flux through the playa bottoms. Six cropland playas and 3 grassland playas had significant hydroperiods with associated consistent instrumentation operation during the 6-year study across the years 2005 to 2011. The average observed infiltration flux rates were approximately 10 millimeters/day (range 2 to 20 millimeters/day) and 3 millimeters/day (range 1 to 5 millimeters/day) 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 runoff 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.

Keywords


playas, infiltration, Ogallala Aquifer, evaporation

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Copyright (c) 2016 Geetha Ganesan, Ken Rainwater, Dennis Gitz, Nicholas Hall, Richard Zartman, Wayne Hudnall, Loren Smith

Texas Water Journal

The Texas Water Journal is an online, peer-reviewed journal devoted to the timely consideration of Texas water resources management, research, and policy issues from a multidisciplinary perspective that integrates science, engineering, law, planning, and other disciplines. It also provides updates on key state legislation and policy changes by Texas administrative agencies. The journal is published by the Texas Water Journal, a nonprofit organization, in cooperation with the Texas Water Resources Institute, part of Texas A&M AgriLife.

ISSN 2160-5319
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