This raster dataset (GeoTIFF) represents the depth to groundwater below the ground surface using a color ramp. These data represent groundwater levels in California during spring 2012. This layer is a smoothed approximation of the groundwater level 'surface' based on the measurement data. The measurement values may not exactly match the color ramp values because of the smoothing process. Water level measurements are selected based on measurement data and well construction information (where available) and approximate groundwater levels in the unconfined to uppermost semi-confined aquifers. This layer is intended to be used as a compliment to data, reports, and other information provided by the California Groundwater Information Center.