ASSESSING THE FEASIBILITY OF RECHARGE ENHANCEMENT FROM PLAYA LAKES ON THE TEXAS HIGH PLAINS

The Texas Water Development Board is researching methods of increasing groundwater recharge from playa lakes to the High Plains Aquifer in the Texas Panhandle. Accurate estimates of the flooding frequency, volume, and duration in the playas are important in determining the engineering feasibility of playa recharge proposals, but no long-term records of playa water levels were available when the current effort was initiated in 2009. Over 120 Landsat images were analyzed and coupled with high resolution topographic surveys to reconstruct hydrographs of selected playas for the period from 2002 to 2012. The GIS hydrographs are compared with field monitoring data for 2011-2012, and are used to assess the variation of infiltration and recharge rates during wet and dry cycles. The reconstructed hydrographs also provide a means to identify playas where engineered modifications to increase recharge may be feasible, while screening out playas where the frequency, volume, or duration of flooding is insufficient to justify water resource investments. Preliminary screening suggests that playa modifications for recharge enhancement will need to be selectively implemented. Further modeling and analysis of modification alternatives is planned to assess costs and effectiveness.