The benefit of a healthy playa — a playa with a grass buffer and no hydrological modifications such as pits or ditches — goes beyond simple recharge. Studies show that water reaching the aquifer through playas is of higher quality than that going through other pathways. This happens in two ways: first, as rainfall and runoff travel toward the playa, the surrounding grasses trap sediments, which can carry contaminants into the playa; then, as the water moves through the clay floor of the playa, a second ‘cleaning’ process occurs as the soils beneath the playa remove nitrates and other dissolved contaminants, which are common in agricultural areas.

“Nitrates will break down in the absence of oxygen,” explains Andy Weinberg, a geoscientist with the Texas Water Development Board. “One of the things about playas with their heavy clay soil, when the soil is saturated the oxygen gets pulled out of the system. As water moves through the cracks in the clay, the nitrate gets reduced back down to nitrogen, and it’s lost out of the system.”

The result is high-quality water reaching the aquifer that can be used by those living on the land