These data represent potential areas of ground-water discharge for selected hydrographic areas in eastern Nevada and western Utah. The data are based on phreatophyte boundaries published by the U.S. Geological Survey (USGS) and on unpublished boundaries mapped by the Southern Nevada Water Authority (SNWA). Selected basins also were mapped by the USGS during an aerial field reconnaissance. The largest phreatophyte extent from all the sources was typically selected as the final boundary where a basin was covered by multiple boundaries. Selected basins were field verified and modified to reflect the ground condition during the summer of 2005. This data set also includes subbasin boundaries identified by Sweetkind and others (2007) (See Source_Information). The table below lists the boundary sources for each valley and whether the data were ground verified.

> Valley Sources Field > verified

>Little Smoky Nichols, 2000; Harrill, 1988 Yes >Newark Nichols, 2000; Harrill, 1988 Yes >Long Nichols, 2000; Harrill, 1988; SNWA Yes >Jakes Nichols, 2000; SNWA Yes >Butte Nichols, 2000; Harrill, 1988; SNWA Yes >Steptoe Nichols, 2000; Harrill, 1988; SNWA No >Tippett Nichols, 2000 No >Spring Nichols, 2000; Harrill, 1988; SNWA Yes >Snake Harrill, 1988; SNWA; Aerial No >Lake Harrill, 1988; SNWA; Aerial Yes >Cave SNWA; Aerial No >White River Harrill, 1988; SNWA; Aerial Yes