Site data contained in the ScrIntrvls_AllSrcRefs_AllWellsRev.csv dataset define the top and bottom altitudes of well screens in 64,763 irrigation wells completed in the Mississippi River Valley alluvial aquifer (MRVA) that constitute a production zone in the Mississippi Alluvial Plain (MAP) extending across the midwestern and southern United States from Illinois to Louisiana. Each well entry contains an Enumerated Domain Value of the Attribute Label SrcRefNo to identify the state environmental agency that contributed to the database, and enumerated values are associated with specific state agencies by using the Enumerated Domain Value Definition. Screen-top and -bottom altitudes and land surface are referenced (corrected) to the National Elevation Dataset (NED) 10-meter digital elevation model (DEM; https://nationalmap.gov/elevation.html). The dataset identifies 50,103 screen-bottom altitudes and 50,457 screen-top altitudes that were used in subsequent geostatistical estimation after spatial analytics filtered out duplicate-coordinate wells, geographic and stratigraphic outliers, and incongruities of screen-top and -bottom altitudes compared with DEM land-surface altitude and the published digital surface of the bottom altitude of the MRVA (https://doi.org/10.3133/sim3426). Well entries are indexed in the dataset to identify use in four regional geostatistical models that collectively encompass the MAP extent and provide gridded estimates of screen-top and-bottom altitudes and estimation uncertainty (estimation variance) associated with each gridded altitude estimate. Digital surfaces of screen-top and -bottom estimates and estimation variances are represented as raster datasets that were converted to netCDF format and conform with the previously published National Hydrologic Grid (https://doi.org/10.5066/F7P84B24) at one-kilometer resolution. This dataset contains high-quality map images for gridded estimates of MRVA screen-top and -bottom altitude and for corresponding gridded estimation variances saved in the Tagged Image File (.tif) format.
|Title||Digital surfaces and site data of well-screen top and bottom altitudes defining the irrigation production zone of the Mississippi River Valley alluvial aquifer within the Mississippi Alluvial Plain project region|
|Authors||Lynn J Torak|
|Product Type||Data Release|
|Record Source||USGS Digital Object Identifier Catalog|
|USGS Organization||South Atlantic Water Science Center|