This dataset consists of a raster and surficial shapefiles for the Neversink River watershed, NY, that were generated using ArcGIS Pro's deep learning functionality. The shapefiles contain polygons that show the locations of shallow-to-exposed bedrock and alluvium-filled valleys, while the raster provides estimated minimum sediment thicknesses in the areas between the shallow/exposed bedrock and alluvium-filled valleys. The deep learning model that generated shallow/exposed bedrock and alluvium polygons was trained on existing geologic maps of New York and Pennsylvania. Minimum sediment thicknesses were estimated by applying an inverse distance weighting interpolation to measurements of stream incision depth and edges of shallow/exposed bedrock zones (where sediment thickness ≈ 0 m). In this area, stream incision through bedrock was considered negligible. The interpolation used variable numbers of points, a fixed interpolation distance of 250 m, and an output resolution of 30 m/pixel. Given the possibility that streams may have not completely incised through surficial materials down to bedrock, these estimates are minimum constraints on the true thicknesses of surficial sediments.

The Neversink River watershed (above the Neversink Reservoir) has been a focus of U.S. Geological Survey (USGS) research regarding stream geochemistry, acidification, and ecology dynamics for decades. In 2019, the Water Mission Area Next Generation Water Observing Systems Program augmented the existing stream gage network there, including instrumentation to specifically characterize various aspects of groundwater discharge to streams. An important control on the spatiotemporal dynamics of groundwater discharge can be stream valley corridor depth to bedrock, otherwise conceptualized as the thickness of unconsolidated sediments sediments over the contiguous bedrock interface. In June 2019, and November 2020, passive seismic recordings were acquired at locations directly along stream banks in the Neversink River watershed, using MOHO Tromino Model TEP-3C (MOHO, S.R.L.) three-component seismometers to assess depth to bedrock using the horizontal-to-vertical spectral-ratio (HVSR) method. Resonance frequencies were derived from the raw data using the GRILLA software (MOHO, S.R.L.) and converted to inferred depths to the bedrock contact. This method requires a value for seismic shear wave velocity, which depends on the unconsolidated sediment composition and density, for the conversion of HVSR measured resonance frequency to a depth to bedrock. Possible shear wave velocities were estimated for Neversink River watershed sediment based on previous research in the glacial terrain of the Northeast USA, providing a range of possible data interpretations as shown in the ‘Processed_Data’ folder of this data release. We expect to update the release in the future as additional HVSR data are collected.

The Neversink River watershed (above the Neversink Reservoir) has been a focus of U.S. Geological Survey (USGS) research regarding stream geochemistry, acidification, and ecology dynamics for decades. In 2019, the Water Mission Area Next Generation Water Observing Systems Program augmented the existing stream gage network there, including instrumentation to specifically characterize various aspects of groundwater discharge to streams. An important control on the spatiotemporal dynamics of groundwater discharge can be stream valley corridor depth to bedrock, otherwise conceptualized as the thickness of unconsolidated sediments sediments over the contiguous bedrock interface. In June 2019, and November 2020, passive seismic recordings were acquired at locations directly along stream banks in the Neversink River watershed, using MOHO Tromino Model TEP-3C (MOHO, S.R.L.) three-component seismometers to assess depth to bedrock using the horizontal-to-vertical spectral-ratio (HVSR) method. Resonance frequencies were derived from the raw data using the GRILLA software (MOHO, S.R.L.) and converted to inferred depths to the bedrock contact. This method requires a value for seismic shear wave velocity, which depends on the unconsolidated sediment composition and density, for the conversion of HVSR measured resonance frequency to a depth to bedrock. Possible shear wave velocities were estimated for Neversink River watershed sediment based on previous research in the glacial terrain of the Northeast USA, providing a range of possible data interpretations as shown in the ‘Processed_Data’ folder of this data release. We expect to update the release in the future as additional HVSR data are collected.

This data release documents streambed sediment thickness in the Neversink watershed (NY) as determined by field observations and HVSR passive seismic measurements, and were collected as an extension of a previous data set collected in the same watershed (see Associated Items). These measurements were made between May 17, 2021 and May 21, 2021 using MOHO Tromino three-component seismometers (MOHO, S.R.L.). Seismic observations were converted to sediment thickness (depth to bedrock, meters) using the horizontal-to-vertical spectral ratio (HVSR) method. Resonance frequencies were determined from time domain data using GRILLA (MOHO, S.R.L.) software and converted to inferred depth to bedrock for a range of possible values for sediment shear wave velocity, as determined from field observations, ground truthing, and previous studies in similar sediment types.

This data release documents streambed sediment thickness in the Neversink watershed (NY) as determined by field observations and HVSR passive seismic measurements, and were collected as an extension of a previous data set collected in the same watershed (see Associated Items). These measurements were made between May 17, 2021 and May 21, 2021 using MOHO Tromino three-component seismometers (MOHO, S.R.L.). Seismic observations were converted to sediment thickness (depth to bedrock, meters) using the horizontal-to-vertical spectral ratio (HVSR) method. Resonance frequencies were determined from time domain data using GRILLA (MOHO, S.R.L.) software and converted to inferred depth to bedrock for a range of possible values for sediment shear wave velocity, as determined from field observations, ground truthing, and previous studies in similar sediment types.

The Mississippi Alluvial Plain (MAP) has become one of the most important agricultural regions in the US, and it relies heavily on a groundwater system that is poorly understood and shows signs of substantial change. The heavy use of the available groundwater resources has resulted in significant groundwater-level declines and reductions in base flow in streams within the MAP. These impacts are limiting well production and threatening future water-availability for the region. This product will help not only scientists in our center, but also at a national level. This product will also be part of a larger study encompassing the Mississippi Alluvial Plain region. The Mississippi Alluvial Plain extent was delineated using GIS tools to represent the geographic extent of the Mississippi Alluvial Aquifer through incorporation of elevation information, geomorphology knowledge, ecological region extent, and previously published extents for part of the MAP region. The current MAP extent represents version 1.0. Future changes to the MAP extent will be tracked through increasing version numbers.

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 is a raster surface, in feet, of the depth to water, spring 2016, Mississippi River Valley alluvial aquifer (MRVA). The raster cell size is 1,000 meters (3,280.8 ft). . The raster was interpolated using (1) depth-to-water (GW_D2W) data from wells and (2) an assumed value of zero for depth to water at streamgages (SW_D2W) because the precise depth to groundwater at the streamgage is not known. The streamgage data is used only when it appears the regional aquifer and surface water are hydrologically connected.

Data release containing geospatial data and metadata for select hydrogeologic characteristics of the alluvium in the Lower Arkansas River Valley, Southeast Colorado, 2002, 2008, and 2015. This data release accompanies U.S. Geological Survey Scientific Investigations Map 3378 (https://doi.org/10.3133/sim3378). Geospatial datasets and metadata include: - Rasters showing estimated thickness of the alluvium; fall-to-fall and spring-to-spring water-table altitude change, 2002 to 2008, 2008 to 2015, and 2002 - 2015; and estimated saturated thickness in the alluvium, fall and spring 2002, 2008, and 2015. - Shapefiles showing bedrock contours underlying the alluvium; the outline of the study area and John Martin Reservoir in Bent County, Colorado; well locations and measured water-level altitude in those wells in the fall and spring of 2002, 2008, and 2015. For the purposes of this data release, "fall" is defined as June 1 through November 30, and "spring" is defined as January 1 through May 31 and December 1 through 31 of the same year.