Paul E Stackelberg

Datasets from Groundwater-Quality and Select Quality-Control Data from the National Water-Quality Assessment Project, January through December 2015 and Previously Unpublished Data from 2013-2014

Groundwater-quality data were collected from 502 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Project and are included in this data release. Most of the wells (500) were sampled from January through December 2015 and 2 of them were sampled in 2013. The data were collected from five types of well networks: principal aquifer study networks, which are used to assess the quality of groundwater used for public water supply; land-use study networks, which are used to assess land-use effects on shallow groundwater quality; major aquifer study networks, which are used to assess the quality of groundwater used for domestic supply; enhanced trends networks,...

Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Cycle 3, NAWQA, National Water Quality Program, USGS Science Data Catalog (SDC), Water Quality, All tags... cycle 3, groundwater, nawqa, water quailty, Fewer tags

Data for machine learning predictions of pH in the glacial aquifer system, northern USA

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...

Categories: Data; Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Boosted regression trees, Calcite saturation index, Connecticut, Geochemistry, Geochemistry, All tags... Glacial aquifer system, Groundwater, Groundwater corrosivity, Hydrology, Idaho, Illinois, Indiana, Iowa, Kansas, Machine learning, Maine, Massachusetts, Michigan, Minnesota, Missouri, Montana, NAWQA, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, Pennsylvania, Rhode Island, South Dakota, USGS Science Data Catalog (SDC), Vermont, Washington, Water Quality, Wisconsin, pH, Fewer tags

Datasets from Groundwater-Quality Data from the National Water-Quality Assessment Project, January through December 2014 and Select Quality-Control Data from May 2012 through December 2014

Groundwater-quality data were collected from 559 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Program from January through December 2014. The data were collected from four types of well networks: principal aquifer study networks, which assess the quality of groundwater used for public water supply; land-use study networks, which assess land-use effects on shallow groundwater quality; major aquifer study networks, which assess the quality of groundwater used for domestic supply; and enhanced trends networks, which evaluate the time scales during which groundwater quality changes. Groundwater samples were analyzed for a large number of water-quality...

Categories: Data; Types: Citation, Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Hydrogeology, NAWQA, National Water Quality Program, USGS Science Data Catalog (SDC), United States, All tags... Water Quality, cycle 3, groundwater, groundwater, nawqa, water quality, Fewer tags

Data Release for Evaluation of Six Methods for Correcting Bias in Estimates from Ensemble Tree Machine Learning Regression Models

Ensemble-tree machine learning (ML) regression models can be prone to systematic bias: small values are overestimated and large values are underestimated. Additional bias can be introduced if the dependent variable is a transform of the original data. Six methods were evaluated for their ability to correct systematic and introduced bias: (1) empirical distribution matching (EDM); (2) regression of observed on estimated values (ROE); (3) linear transfer function (LTF); (4) linear equation based on Z-score transform (ZZ); (5) second machine learning model used to estimate residuals (ML2-RES); and (6) Duan smearing estimate applied after ROE is implemented (ROE-Duan). The performance of the methods was evaluated using...

Categories: Data; Tags: Central Valley, California, Glacial aquifer system, Mississippi Embayment, NAWQA, North Atlantic Coastal Plain, All tags... USGS Science Data Catalog (SDC), Water Quality, cycle 3, groundwater, hydrology, machine learning, regression model, Fewer tags

Data for depth of groundwater used for drinking-water supplies in the United States

This data release includes grids representing the depth and thickness of drinking-water withdrawal zones, polygons of hydrogeologic settings, an inventory of sources of well construction data, and summaries of data comparisons used to assess the depth of groundwater used for drinking-water supplies in the United States. Well construction data sources are documented in Table1_DataSources.xlsx. Data comparisons using the Mann-Whitney test to assess similarity between hydrogeologic settings were used to justify combining data where they were sparse (compare_neighbors_all_domestic.txt and compare_neighbors_all_public.txt). Water-supply-well depth varies geographically by water use and the type of well, which illustrates...

Categories: Data, Data Release - Revised; Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Cycle 3, Hydrology, NAWQA, USGS Science Data Catalog (SDC), United States, All tags... Water Quality, Water Resources, aquifers, domestic well water use, drinking water use, groundwater, public supply water use, water quality, Fewer tags