In response to a need to better understand how ground-water and streamflow conditions are related to riparian vegetation condition and water use, a study was completed by the U.S. Geological Survey, Arizona State University, and the Department of AgricultureARS. Hydrologic (ground-water and streamflow variables), riparian, and evapotranspiration (ET) data were collected from 2000 to 2003 at a series of sites spanning the conditions present within the San Pedro Riparian National Conservation Area (SPRNCA), Upper San Pedro Basin, Arizona. The SPRNCA extends about 60 km north from the U.S. boundary with Mexico and the drainage area above the downstream SPRNCA boundary is about 4,800 km.