A model of transmissivity and hydraulic conductivity from electrical resistivity distribution derived from airborne electromagnetic surveys of the Mississippi River Valley Alluvial Aquifer, Midwest USA

Abstract Groundwater-flow models require the spatial distribution of hydraulic conductivity parameter. One approach to defining this in groundwater-flow model grids is map electrical resistivity by airborne electromagnetic (AEM) survey and establish a petrophysical relation between mean calculated as nonlinear function layering thicknesses layers aquifer transmissivity compiled from historical tests completed within AEM area. The used transform over areas where saturated thickness known. US Geological Survey applied gain better understanding properties Mississippi River Valley alluvial aquifer. Alluvial-aquifer data, 160 Alluvial Plain (MAP), were correlated 16,816 line-kilometers (km) inverted soundings produced frequency-domain 95,000 km 2 MAP. Correlated data define relations omitting correlations aquifer-test sounding that separated distances greater than 1 manually calibrating coefficients slug-test data. yielding minimum residual error simulated was 2,364 line-km 1,000-km Shellmound (Mississippi) study area calculate property distributions for use future models.