Data collection as part of the northern unsaturated zone studies was completed in 2003. The three sites that compose the northern High Plains unsat study will be used to test a hypothesis that focused recharge (leakage of water and chemicals down a poorly sealed annular space of an irrigation well) is a possible dominant mechanism to explain the observed water quality at the water table beneath irrigated fields in the High Plains.

For details on this effort see Borehole Tracer Study: Ogallala Formation-northern High Plains.