Fig. 2. Study design applied to the Washington location. The Yakima River, Granger Drain, and DR2 are the nested watersheds at three scales. The red circles show the location of each well nest. Those designated as "FS" are part of the flow system study. This flow system terminates at the GW/SW interaction study area near the DR2 surface-water gage. The wells designated as "AS" are part of the well network to characterize the local ground water. The unsaturated zone study area includes lysimeters and soil moisture instruments at various depths, a weather station, and a water-table well. There were no tile drain or rain sampling components to this study, since neither of these are important factors in this environment.