This data set consists of water-table contours for Nevada. These data were created as part of an effort to provide statewide information on water table and depth to ground water for Nevada.

The data set was constructed from water-table contours published in 38 reports between 1961 and 2004.
Data used to make the contours were collected from 1947 to 2004. The reports used were a subset of 104 reports identified during a literature search of published water-table and depth to ground-water contours.
Reports used in this data set were chosen based on a scoring system using four criteria: the percentage of the hydrographic area (HA) with contours, the contour interval, the date of the water-level measurements, and whether control points were plotted with the contours. For example, more current water-level measurements were given a higher score than older data and contours covering a high percentage of the HA were scored higher than those that covered less area. If not already available digitally, the contours were digitized from the selected report and combined to make the statewide data set. Although depth to ground-water contours were available from several of the reports, the selection process resulted in only water-table contours being used in all areas except HA 153, Diamond Valley. Depth to ground- water contours based on well measurements from the year 2001 were used in this HA because a large change in ground-water levels had occurred since ground-water altitude contours were published in 1968.
To generate the final water-table data set, digitized contours from the selected reports were merged into a single data set. Contours from a single report were chosen where data from different reports covered the same HA. Where few or no contours were available for an HA, data from a statewide report, Bedinger and others (see the source citations) was used to fill in the gaps. The final data set consists of contours representing water levels measured between 1947 and 2004, most of which are in unconfined to semiconfined unconsolidated sediment aquifers.