The Missouri Department of Natural Resources’ (MoDNR) Well Information Management System (WIMS) is a repository for well information that includes date of completion, well construction, geology, and water level. Well information is provided by the water well drillers during the permitting process and is updated periodically by MoDNR. Well information is available in WIMS as early as 1983 to the present. This data set consists of 16,639 well records extracted from WIMS that were likely drilled into the Mississippi River Valley alluvial aquifer in Missouri. Records that may not reflect the true groundwater conditions in the aquifer were identified using a series of criteria described in detail below. The threshold criteria are described in detail in the “entity and attribute” section.

An objective review (Asquith and others, 2018 and 2020) of the distribution of the first two significant figures of a water-level measurement (depth below land surface) was done on the 10,295 measurements (one per well) that met the threshold criteria. The purpose of this review was to ascertain the degree to which substantial rounding of values might exist in the dataset. It was evident that the dataset has a large number of values rounded to the nearest integer foot with a tendency for more rounding towards even integers. For values between 10 and 99 feet, there is a large number of values rounded to the even 10 feet and for values less than about 35 feet, there are an excessive number of values rounded the nearest. There are also numerous values of 12 and 14. This suggests that considerable estimation or rounding of water levels have been made probably by use of apparatus other than graduate tapes. Systematic review of original data sources is not possible and insufficient metadata exist for a manual of each value in the data set. However, the database is large and offers an opportunity for data mining and machine learning to foster further review. A large, objective, technically-demanding, and rigorous spatial-temporal review of the water-level data, expressed in altitude, was made for the 10,295 water level records comprising this data release.

An objective review (Asquith and others, 2018 and 2020) of the distribution of the first two significant figures of a water-level measurement (depth below land surface) was done on the 10,295 measurements (one per well) that met the threshold criteria. The purpose of this review was to ascertain the degree to which substantial rounding of values might exist in the dataset. It was evident that the dataset has a large number of values rounded to the nearest integer foot with a tendency for more rounding towards even integers. For values between 10 and 99 feet, there is a large number of values rounded to the even 10 feet and for values less than about 35 feet, there are an excessive number of values rounded the nearest. There are also numerous values of 12 and 14. This suggests that considerable estimation or rounding of water levels have been made probably by use of apparatus other than graduate tapes. Systematic review of original data sources is not possible and insufficient metadata exist for a manual of each value in the data set. However, the database is large and offers an opportunity for data mining and machine learning to foster further review. A large, objective, technically-demanding, and rigorous spatial-temporal review of the water-level data, expressed in altitude, was made for the 10,295 water level records comprising this data release.

This data set provides information about wells in the State of Missouri. The parent data set is the Wellhead Information Management System (WIMS) database that is maintained by the Missouri Department of Natural Resources (DNR), Missouri Geological Survey (MGS), Geological Survey Program (GSP), Wellhead Protection Section (WHP). The WIMS database resulted from implementation of the Water Well Drillers Law of 1985. The information about well location, well ownership, well completion date, well construction, well yield, static water level, and borehole stratigraphy was provided by well drillers as required by state statute RSMo 256.600-256.640. Wells drilled prior to July of 1987 are not included in this data set. A WIMS Well Search is also available online at http://dnr.mo.gov/mowells/publicLanding.do These data were formally named MO_2015_Wells_shp.zip which have been removed from MSDIS at MO Office of Administration request.

This dataset contains the final water-level records (334) that met all threshold criteria and had an absolute residual (ABS_PSEUDO_LEV) of less than 20 feet. The threshold of 20 feet was selected based on water-level changes of the U.S. Geological Survey groundwater site 363551090152801 Qulin, in the Mississippi River Valley alluvial aquifer. This final dataset is considered a best representation of the true water-levels in the aquifer.

This dataset contains the final water-level records (334) that met all threshold criteria and had an absolute residual (ABS_PSEUDO_LEV) of less than 20 feet. The threshold of 20 feet was selected based on water-level changes of the U.S. Geological Survey groundwater site 363551090152801 Qulin, in the Mississippi River Valley alluvial aquifer. This final dataset is considered a best representation of the true water-levels in the aquifer.

A potentiometric-surface map represents the altitude at which water would stand in tightly cased wells completed at any location within the study area aquifer. Using the altitude of water levels measured in the study area, the potentiometric-surface map depicts points of equal altitude with contours denoting a given water-level altitude calculated by subtracting the water level measured from the land-surface elevation (National Geodetic Vertical Datum of 1929). The contour lines were created using computer-based program ArcGIS with an interval of 10 feet. The direction of water flow from areas of high elevation to low elevation can be interpreted using potentiometric-surface maps and areas of decreased groundwater levels can be identified. The 2014 potentiometric-surface map shows ten total cones of depressions: two large depressions, five small depressions, and three areas of decreased water levels. As with the 2010 potentiometric-surface map, one large depression begins in southeastern Arkansas County, near the Arkansas and Desha County line, and extends north into Prairie County, west into Lonoke County, and east into the western-most part of Monroe County. Even though the center of the depression had deepened in 2010, the area of the cone in Arkansas County within the southeastern half of the depression had not expanded horizontally. The analysis of the 2014 potentiometric-surface map suggests no horizontal expansion in this area. The additional GIS shapefiles were used to depicts the western extent of the Mississippi River alluvial aquifer in eastern Arkansas on plates 1, 2, and 3 in Rodgers and Whaling (2020).

A potentiometric-surface map represents the altitude at which water would stand in tightly cased wells completed at any location within the study area aquifer. Using the altitude of water levels measured in the study area, the potentiometric-surface map depicts points of equal altitude with contours denoting a given water-level altitude calculated by subtracting the water level measured from the land-surface elevation (National Geodetic Vertical Datum of 1929). The contour lines were created using computer-based program ArcGIS with an interval of 10 feet. The direction of water flow from areas of high elevation to low elevation can be interpreted using potentiometric-surface maps and areas of decreased groundwater levels can be identified. The 2014 potentiometric-surface map shows ten total cones of depressions: two large depressions, five small depressions, and three areas of decreased water levels. As with the 2010 potentiometric-surface map, one large depression begins in southeastern Arkansas County, near the Arkansas and Desha County line, and extends north into Prairie County, west into Lonoke County, and east into the western-most part of Monroe County. Even though the center of the depression had deepened in 2010, the area of the cone in Arkansas County within the southeastern half of the depression had not expanded horizontally. The analysis of the 2014 potentiometric-surface map suggests no horizontal expansion in this area. The additional GIS shapefiles were used to depicts the western extent of the Mississippi River alluvial aquifer in eastern Arkansas on plates 1, 2, and 3 in Rodgers and Whaling (2020).

This dataset contains the final water level records (10,132) that met all threshold criteria and had absolute residual (ABS_PSEUDO_LEV) of less than 20 feet. The threshold of 20 feet was selected based on water level changes of the U.S. Geological Survey groundwater site 363551090152801 Qulin in the Mississippi River Valley alluvial aquifer. This final dataset is considered a best representation of the true water levels in the aquifer.

This dataset contains the final water level records (10,132) that met all threshold criteria and had absolute residual (ABS_PSEUDO_LEV) of less than 20 feet. The threshold of 20 feet was selected based on water level changes of the U.S. Geological Survey groundwater site 363551090152801 Qulin in the Mississippi River Valley alluvial aquifer. This final dataset is considered a best representation of the true water levels in the aquifer.