PLAYA LAKES ON THE SOUTHERN HIGH-PLAINS IN TEXAS - REEVALUATING INFILTRATION

The fate of water in playa lakes determines the long-term water manage ment strategy for the Southern High Plains of Texas. To determine the fate of water within playa wetlands, initial (1 min) and long-term (>4 8 b) infiltration rates were determined using double ring infiltromete rs at three relative elevations in three Southern High Plains playa la kes. The high elevation treatments were at least 150 mm above the high est intermediate elevation and the low elevation treatments were at le ast 150 mm below the lowest intermediate elevation. The hydric playa s oils [Randall clay (fine, smectitic, thermic Udic Pellusterts)] were v egetated with facultative wetland plants. Particle size analysis, soil PH, and electrical conductivity were also determined at each infiltro meter location. There were no significant differences of infiltration for the three elevational treatments. Initial infiltration rates range d from 2490 to 10 mm/min while arithmetic means were greater than 100 mm/min. Long-term infiltration rates ranged from 996 to 0.004 mm/min w hile arithmetic means were approximately 5 mm/min. These rapid initial and measurable long-term infiltration rates demonstrate that infiltra tion occurs within playas. Furthermore, these high infiltration rates indicate that playa wetlands are important zones in determining the fa te of surface water on the Southern High Plains.