This data set represents the extent of the Lower Tertiary aquifers in the states of North Dakota, South Dakota, Wyoming, and Montana.

This data set represents the extent of the Paleozoic aquifers in the states of South Dakota, Wyoming, and Montana.

This data set represents the extent of the Lower Cretaceous aquifers in the states of Montana, Wyoming, South Dakota, Kansas, Nebraska, Iowa, and Minnesota..

This data set represents the extent of the Upper Cretaceous aquifers in the states of North Dakota, South Dakota, Wyoming, and Montana.

This data set represents the extent of the Arbuckle-Simpson aquifer in Oklahoma.

This data set represents the extent of the Volcanic and sedimentary-rock aquifers in the states of Montana, Wyoming, Idaho, Nevada, California, Oregon, and Washington.

This data set represents the extent of the Northern Rocky Mountains Intermontane Basins aquifer system in Montana and Idaho.

This data set consists of digital water-level-change contour for the High Plains aquifer in the Central United States, 1980 to 1994. The High Plains aquifer extends from south of 32 degrees to almost 44 degrees north latitude and from 96 degrees 30 minutes to 104 degrees west longitude. The aquifer underlies about 174,000 square miles in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. This digital data set was created from 6,143 wells measured in both 1980 and 1994. The water-level-change contours were drawn manually on mylar. The contours were converted into a digital map at a scale of 1:1,250,000. The data should not be used at scales larger than 1:1,250,000.

The upper portion of the Troublesome Aquifer is the sole source of water for domestic use in the Greater Pole Creek Basin, situated in the western portion of the upper Fraser River Valley in Grand County, Colorado. Data from drilling records for wells installed near and within recent home developments, municipal water-suppliers, water-quality records, and published reports are summarized as an initial synthesis of aquifer water quantity and quality. In spite of persistent drought and increased domestic aquifer-water usage, aquifer water storage remains robust with water levels little changed during the past 25 years. Water-quality data indicate substantial variability with depth beneath the top of the aquifer. Data from wells completed in the overlying shallow alluvial aquifer are also presented for comparison. This document constitutes a new baseline for assessment of current and future groundwater resources within this portion of the upper Fraser River valley. Suggested future investigations include water-table monitoring and comprehensive water-quality surveys for water derived from wells completed in the Troublesome Aquifer.

This USGS data release consists of two geospatial raster datasets and three geospatial vector data sets of water-level data. The data sets include a raster (A1) representing water-level change from predevelopment (about 1950) to 2015; the primary vector dataset (A2) of water-level-change data of static or near-static water levels in wells measured in predevelopment and 2015 (for wells in Colorado, Kansas, Nebraska, Oklahoma, South Dakota, and Texas) and in wells measured in predevelopment and the latest available static or near-static water level from 2011 to 2015 (for wells in New Mexico and Wyoming), a supplemental vector dataset (A3) of water-level data used to manually substantiate the raster of water-level change from predevelopment (about 1950) to 2015, a raster (B1) representing water-level change from 2013 to 2015; and the vector dataset (B2) of water-level-change data for wells measured in 2013 and 2015. The supplemental vector data sets of water-level-change data used to manually substantiate the raster of water-level change from predevelopment (about 1950) to 2015 are composed of (1) water-level-change data from wells measured before June 15, 1978, but not during or before the predevelopment period for the area, and in 2015, (2) for wells not measured in predevelopment or before June 15, 1978 but measured in 1980 and in 2015, calculated water-level-change data derived from the sum of the water-level-change value from 1980 to 2015 and the beginning water-level-change value from the contours of water-level change, predevelopment to 1980 (Luckey and others, 1981; Cederstrand and Becker, 1999), (3) water-level-change data for wells located in Colorado, Kansas, Nebraska, Oklahoma, South Dakota, and Texas and measured in predevelopment and 2014 and not measured in 2015, (4) water-level-change data for wells located in Colorado, Kansas, Nebraska, Oklahoma, South Dakota, and Texas and measured in measured in predevelopment and 2013 and not measured in 2014 or in 2015, (5) the water-level-change data for wells located in Colorado, Kansas, Nebraska, Oklahoma, South Dakota, and Texas and measured in measured in predevelopment and 2012 and not measured in 2013, 2014, or 2015, (6) the water-level-change data for wells located in Colorado, Kansas, Nebraska, Oklahoma, South Dakota, and Texas and measured in measured in predevelopment and 2011 and not measured in 2012, 2013, 2014, or 2015. The raster and vector data support USGS Scientific Investigations Report 2017-5040, Water-Level Changes and Change in Recoverable Water in Storage in the High Plains Aquifer, Predevelopment to 2015 and 2013-15.