Mississippi Alluvial Plain (MAP): Streambed Properties &amp; Connectivity

Electrical resistivity results from four regional airborne electromagnetic (AEM) surveys (Burton et al. 2024, Hoogenboom et al. 2023, Minsley et al. 2021, Burton et al. 2021) over the Mississippi Alluvial Plain (MAP) were combined by the U.S. Geological Survey (USGS) to produce three-dimensional (3D) gridded models and derivative hydrogeologic products. To calculate estimates of streambed properties across the MAP region, e.g. the relative connection potential between streams and the adjacent Mississippi River Valley Alluvial aquifer (MRVA), new 3D grids of electrical resistivity were generated for 2 meter (m) depth layers and only shallow depths (0-30 m). One grid was made with the horizontal dimension aligning with the 1 kilometer (km) x 1 km National Hydrogeologic Grid (NHG; Clark et al. 2018), and a second version was generated at a finer resolution of 100 m x 100 m, subdividing the NHG grid. Stream locations taken from the National Hydrograph Dataset Plus (NHDPlus) high resolution dataset were buffered with a 1.0 km radius and then intersected with both shallow 3D depth grids to isolate resistivity values immediately beneath or adjacent to streams. Twelve “facies classes” were defined to categorize materials expected to have similar hydrologic and geologic properties based on their electrical resistivity (i.e. low classes correspond to clays and silts with low permeability, and higher classes reflect larger grain sizes (sands, gravels) with expected higher permeability). The potential hydraulic connection through streambed sediments was estimated by calculating the vertically integrated electrical conductance (VIC) across each 2 m layer between 0 and 10 m depth. The shallow 3D resistivity and facies grids were exported in NetCDF format with an accompanying XML NetCDF Markdown Language metadata file. The streambed connectivity estimates were exported as raster images in Georeferenced Tagged Image File Format (GeoTIFF).
Burton, B.L., Adams, R.F. Adams, Minsley, B.J., Pace, M.D.M., Kress, W.H., Rigby, J.R., and Bussell, A.M., 2024, Airborne electromagnetic, magnetic, and radiometric survey of the Mississippi Alluvial Plain, March 2018 and May - August 2021: U.S. Geological Survey data release, https://doi.org/10.5066/P9KPK3UJ.
Hoogenboom, B.E., Minsley, B.J., James, S.R., and Pace, M.D., 2023, Airborne electromagnetic, magnetic, and radiometric survey of the Mississippi Alluvial Plain, Mississippi Embayment, and Gulf Coastal Plain, September 2021 - January 2022: U.S. Geological Survey data release, https://doi.org/10.5066/P93DO0EO.
Burton, B.L., Minsley, B.J., Bloss, B.R., and Kress, W.H., 2021, Airborne electromagnetic, magnetic, and radiometric survey of the Mississippi Alluvial Plain, November 2018 - February 2019: U.S. Geological Survey data release, https://doi.org/10.5066/P9XBBBUU.
Clark, B.R., Barlow, P.M., Peterson, S.M., Hughes, J.D., Reeves, H.W., and Viger, R.J., 2018, National-scale grid to support regional groundwater availability studies and a national hydrogeologic database: U.S. Geological Survey data release, https://doi.org/10.5066/F7P84B24.
Minsley, B.J., James, S.R., Bedrosian, P.A., Pace, M.D., Hoogenboom, B.E., and Burton, B.L., 2021, Airborne electromagnetic, magnetic, and radiometric survey of the Mississippi Alluvial Plain, November 2019 - March 2020: U.S. Geological Survey data release, https://doi.org/10.5066/P9E44CTQ.

Tags: 3d, arkansas, arkansas-river, electromagnetic-surveying, electromagnetics, engineering-sciences, environment, geology-geophysics-and-geochemistry-science-center, geophysics, geoscientificinformation, geospatial-datasets, gggsc, groundwater, hydrogeology, illinois, louisiana, mississippi, mississippi-alluvial-plain, mississippi-river, mississippi-river-valley-alluvial-aquifer, missouri, mrva, resistivity, tennessee, three-dimensional, u-s-geological-survey, usgs, usgs-5f0e093682ce21d4c4053edc, water-availability-and-use-science-program, water-resources, wausp
Organization: Department of the Interior