Sandra Eberts is a Professional Hydrogeologist. She holds B.S. and M.S. degrees in Geology from The Ohio State University and a Certificate in Legislative Studies from Georgetown University. Sandy has been with the USGS for more than 30 years and has experience developing and leading multidisciplinary scientific program at the regional and national level. She serves as the USGS representative to the Source Water Collaborative—27 national organizations united to protect America's sources of drinking water. She is a member of the American Water Works Association Groundwater Committee, the International Joint Commission Science Advisory Board - Research Coordination Committee and the Great Lakes Water Quality Agreement Annex 4 Objectives and Targets Task Team. Sandy is the Program Science Coordinator for the USGS Water Resources Mission Area, Office of Planning and Programming (OPP).
Intense demand for water in the Central Valley of California and related increases in groundwater nitrate concentration threaten the sustainability of the groundwater resource. To assess contamination risk in the region, we developed a hybrid, non-linear, machine learning model within a statistical learning framework to predict nitrate...
Ransom, Katherine M.; Nolan, Bernard T.; Traum, Jonathan A.; Faunt, Claudia; Bell, Andrew M.; Gronberg, Jo Ann M.; Wheeler, David C.; Zamora, Celia; Jurgens, Bryant; Schwarz, Gregory E.; Belitz, Kenneth; Eberts, Sandra; Kourakos, George; Harter, Thomas No abstract available.
Muenich, Rebecca Logsdon; Johnson, Laura; Bratton, John F.; Fussell, Kristin DeVanna; Kane, Doug; Kalcic, Margaret; Robertson, Dale M.; Eberts, Sandra; Evans, Mary; Gibbons, Kenneth J.
Cyanobacterial harmful algal blooms (CyanoHABs) are increasingly a global concern because CyanoHABs pose a threat to human and aquatic ecosystem health and cause economic damages. Despite advances in scientific understanding of cyanobacteria and associated compounds, many unanswered questions remain about occurrence, environmental triggers for...
Graham, Jennifer L.; Dubrovsky, Neil M.; Eberts, Sandra M. The age distribution of water from a public-supply well in a deep alluvial aquifer was estimated and used to help explain arsenic variability in the water. The age distribution was computed using a ternary mixing model that combines three lumped parameter models of advection-dispersion transport of environmental tracers, which represent relatively...
Jurgens, Bryant; Bexfield, Laura M.; Eberts, Sandra No abstract available.
Böhlke, John Karl; Jurgens, Bryant C.; Uselmann, David J.; Eberts, Sandra M. No abstract available.
Eberts, Sandra Aquifer vulnerability models were developed to map groundwater nitrate concentration at domestic and public-supply well depths in the Central Valley, California. We compared three modeling methods for ability to predict nitrate concentration >4 mg/L: logistic regression (LR), random forest classification (RFC), and random forest regression (RFR...
Nolan, Bernard T.; Gronberg, JoAnn M.; Faunt, Claudia C.; Eberts, Sandra M.; Belitz, Ken
As part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program, a study was conducted from 2001 to 2011 to shed light on factors that affect the vulnerability of water from public-supply wells to contamination (referred to hereafter as “public-supply-well vulnerability”). The study was designed as a follow-up to earlier...
Eberts, Sandra M.; Thomas, Mary Ann; Jagucki, Martha L.
This fact sheet highlights findings from the vulnerability study of a public-supply well in Albuquerque, New Mexico (hereafter referred to as “the study well”). The study well produces about 3,000 gallons of water per minute from the Rio Grande aquifer system. Water samples were collected at the study well, at two other nearby public-supply wells...
Jagucki, Martha L.; Bexfield, Laura M.; Heywood, Charles E.; Eberts, Sandra M.
TracerLPM is an interactive Excel® (2007 or later) workbook program for evaluating groundwater age distributions from environmental tracer data by using lumped parameter models (LPMs). Lumped parameter models are mathematical models of transport based on simplified aquifer geometry and flow configurations that account for effects of...
Jurgens, Bryant C.; Böhlke, J.K.; Eberts, Sandra M.
This fact sheet highlights findings from the vulnerability study of a public-supply well field in San Antonio, Texas. The well field consists of six production wells that tap the Edwards aquifer. Typically, one or two wells are pumped at a time, yielding an average total of 20-21 million gallons per day. Water samples were collected from public-...
Jagucki, Martha L.; Musgrove, MaryLynn; Lindgren, Richard J.; Fahlquist, Lynne; Eberts, Sandra M. Wells screened across multiple aquifers can provide pathways for the movement of surprisingly large volumes of groundwater to confined aquifers used for public water supply (PWS). Using a simple numerical model, we examine the impact of several pumping scenarios on leakage from an unconfined aquifer to a confined aquifer and conclude that a single...
Johnson, R.L.; Clark, B.R.; Landon, M.K.; Kauffman, L.J.; Eberts, S.M.
The USGS Groundwater Age Mixtures and Contaminant Trends Tool (GAMACTT) can be used to explore the effects of basic aquifer properties and well configurations on groundwater age mixtures in groundwater discharge and on contaminant trends from varying nonpoint-source contaminant input scenarios.