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Person

Leon J Kauffman

Hydrologist

New Jersey Water Science Center

Email: lkauff@usgs.gov
Office Phone: 406-754-3332

Location
3450 Princeton Pike
Suite 110
Lawrenceville , New Jersey 08648
US

Supervisor: Jon A Janowicz
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This dataset provides the estimated number of people using publicly supplied groundwater (PSg) or publicly supplied surface water (PSs) for each county in the conterminous U.S. The county boundaries, the PSg, and the PSs represent the year 2010
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The USGS Soil-Water-Balance (SWB) Model was applied to 644 basins as defined at the level of an 8-digit hydrologic unit code (HUC). Support scripts, model inputs, and model outputs are provided in this archive.
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The Lithologic Logs dataset includes state well records, and the well logs were standardized so that the lithologic information used a consistent terminology by Bayless and others (2017). The dataset contains 1,565,051 records, of which 746,568 are for wells that are used for withdrawing water.
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Groundwater age is an important indicator of groundwater susceptibility to anthropogenic contamination and a key input to statistical models for forecasting water quality. Numerical models can provide estimates of groundwater age, enabling interpretation of measured age tracers. However, to extend to national-scale groundwater systems where numerical models are not routinely available, a more efficient metamodeling approach can provide a less precise but widely applicable estimate of groundwater age, trained to make forecasts based on predictor variables that can be measured independent of numerical models. We trained gradient-boosted regression tree statistical metamodels to MODFLOW/MODPATH derived groundwater...
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A boosted regression tree (BRT) model was developed to predict pH conditions in three-dimensions throughout the glacial aquifer system (GLAC) of the contiguous United States using pH measurements in samples from 18,258 wells and predictor variables that represent aspects of the hydrogeologic setting. Model results indicate that the carbonate content of soils and aquifer materials strongly controls pH and when coupled with long flow paths, results in the most alkaline conditions. Conversely, in areas where glacial sediments are thin and carbonate-poor, pH conditions remain acidic. At depths typical of drinking-water supplies, predicted pH > 7.5 – which is associated with arsenic mobilization – occurs more frequently...
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