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Leslie A DeSimone

Leslie DeSimone is a Hydrologist in the New England Water Science Center. 

Leslie serves as the Center Water-Quality Specialist and as an analyst for the National Water-Quality Assessment Project. 

Leslie started with USGS in 1988 and has worked on a broad range of studies on topics such as contaminant occurrence and transport in groundwater, surface-water quality trends and loads, and groundwater flow and availability.

Current work includes:

  • Machine-learning models of groundwater quality in the mid-Atlantic region
  • Technical assistance on water-quality data and studies in New England
  • Water-quality database management

Recent work includes:

  • National compilations of water quality in U.S. Principal Aquifers and in domestic wells
  • Mapping bedrock well yield in eastern Massachusetts

Professional Experience

  • 1988 - present, U.S. Geological Survey - Hydrologist

Education and Certifications

  • Ph.D. Geology, Boston University

  • M.A. Geology, Boston University

  • B.A. Geology, St. John's College, Annapolis, MD

Science and Products

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domestic supply well, FL.

Domestic (Private) Supply Wells

More than 43 million people—about 15 percent of the U.S. population—rely on domestic (private) wells as their source of drinking water. The quality and safety of water from domestic wells are not regulated by the Federal Safe Drinking Water Act or, in most cases, by state laws. Instead, individual homeowners are responsible for maintaining their domestic well systems and for monitoring water...
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Water Resources Mission Area, National Water Quality Program
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Domestic (Private) Supply Wells

More than 43 million people—about 15 percent of the U.S. population—rely on domestic (private) wells as their source of drinking water. The quality and safety of water from domestic wells are not regulated by the Federal Safe Drinking Water Act or, in most cases, by state laws. Instead, individual homeowners are responsible for maintaining their domestic well systems and for monitoring water...
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Pesticides in groundwater can eventually contaminate well water.

Groundwater Quality in Principal Aquifers of the Nation, 1991–2010

What’s in your groundwater? Learn about groundwater quality in the Principal Aquifers of nine regions across the United States in informative circulars filled with figures, photos, and water-quality information.
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Water Resources Mission Area
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Groundwater Quality in Principal Aquifers of the Nation, 1991–2010

What’s in your groundwater? Learn about groundwater quality in the Principal Aquifers of nine regions across the United States in informative circulars filled with figures, photos, and water-quality information.
Learn More
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Girl Drinking Water

Groundwater Quality in Principal Aquifers of the United States, 1991—2010

A new U.S. Geological Survey (USGS) report summarizes the major findings of national and regional assessments of groundwater quality in 40 Principal Aquifers in the United States. Knowledge of contaminant occurrence and the factors that control contaminant concentrations can ensure the availability and quality of this vital natural resource in the future.
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Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology
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Groundwater Quality in Principal Aquifers of the United States, 1991—2010

A new U.S. Geological Survey (USGS) report summarizes the major findings of national and regional assessments of groundwater quality in 40 Principal Aquifers in the United States. Knowledge of contaminant occurrence and the factors that control contaminant concentrations can ensure the availability and quality of this vital natural resource in the future.
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Concentrations of metals and other water quality data for the Assabet and Concord Rivers, Massachusetts, 2008

This dataset contains water-quality data for stream samples collected by the U.S. Geological Survey at 12 sites on the Assabet and Concord Rivers in eastern Massachusetts in 2008. The samples were collected monthly from June to October, 2008. The water-quality parameters and constituents include field parameters (water temperature, specific conductance, pH, and dissolved oxygen), concentrations of
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New England Water Science Center

Data and Model Archive for Preliminary Machine Learning Models of Manganese and 1,4-Dioxane in Groundwater on Long Island, New York

Data and preliminary machine-learning models used to predict manganese and 1,4-dioxane in groundwater on Long Island are documented in this data release. Concentration data used to develop the models were from 910 wells for manganese and 553 wells for 1,4-dioxane, primarily public supply wells, from U.S. Geological Survey, U.S. Environmental Protection Agency (USEPA), and Suffolk County Water Auth
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Water Resources Mission Area

Total and Dissolved Organic Carbon Data to Support Implementation of Revised Freshwater Aluminum Water-Quality Criteria in Massachusetts

This data set contains historical data on concentrations of total and dissolved organic carbon in Massachusetts streams from the U.S. Geological Survey National Water Information System (NWIS) database. The data were compiled from NWIS using site and sample selection criteria to retrieve all publicly available data from surface-water samples that contained analysis of both total and dissolved orga
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New England Water Science Center

Surface-Water-Quality Data and Time-Series Plots to Support Implementation of Site-Dependent Aluminum Criteria in Massachusetts, 2018-19 (ver. 1.1, February 2023)

This data release includes water-quality data collected at 38 sites in central and eastern Massachusetts from April 2018 through May 2019 by the U.S. Geological Survey to support the implementation of site-dependent aluminum criteria for Massachusetts waters. Samples of effluent and receiving surface waters were collected monthly at four wastewater-treatment facilities (WWTFs) and seven water-trea
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New England Water Science Center

Data used to model and map manganese in the Northern Atlantic Coastal Plain aquifer system, eastern USA

Data used to model and map manganese concentrations in groundwater in the Northern Atlantic Coastal Plain (NACP) aquifer system, eastern USA, are documented in this data release. The model predicts manganese concentration within four classes and is based on concentration data from 4492 wells. The well data were compiled from U.S. Geological Survey, U.S. Environmental Protection Agency, Suffolk Cou
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New England Water Science Center

Datasets of Groundwater-Quality and Select Quality-Control Data from the National Water-Quality Assessment Project, January 2017 through December 2019

Groundwater-quality data were collected from 983 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Program and are included in this report. The data were collected from six 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 networ
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Water Resources Mission Area

Data used to model and map pH and redox conditions in the Northern Atlantic Coastal Plain aquifer system, eastern USA

Data used to model and map pH and redox conditions in groundwater in the Northern Atlantic Coastal Plain aquifer system, eastern USA, are documented in this data release. The models use as input data measurements of pH and dissolved oxygen concentrations at about 3000 to 5000 wells, which were compiled primarily from U.S. Geological Survey and U.S. Environmental Protection Agency databases. The bo
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Water Resources Mission Area

Statistical summaries of simulated groundwater residence times for the 10 regional aquifers of the Northern Atlantic Coastal Plain aquifer system, at a 1 square-mile grid resolution

Groundwater residence times were simulated for the major regional aquifers of the Northern Atlantic Coastal Plain aquifer system from New York to North Carolina using particle tracking in a regional groundwater flow model. Millions of particles were distributed throughout the aquifers of the North Atlantic Coastal Plain in a MODFLOW model with a volume-weighted algorithm, then tracked backwards us
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Virginia and West Virginia Water Science Center

Laboratory quality-control data associated with samples analyzed for microbiological constituents at the Ohio Water Microbiology Laboratory, 2012-2017

This dataset contains data tables of laboratory quality-control data associated with environmental samples analyzed for microbiological constituents at the Ohio Water Microbiology Laboratory of the U.S. Geological Survey (USGS) during federal fiscal years 2012-2017 (October 1, 2011 through September 30, 2017). The environmental samples were collected across the United States by the USGS National W
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Ohio-Kentucky-Indiana Water Science Center

Bedrock well yield, lineaments, and ancillary data in the Nashoba Terrane, central and eastern Massachusetts

This data release contains well yield and ancillary data for 7,287 bedrock wells used in an analysis of bedrock well yield in the Nashoba Terrane and surrounding area in eastern and central Massachusetts. The data release also contains Geographic Information System (GIS) data layers of lineaments delineated from aerial photographs and digital elevation data for a part of the Nashoba Terrane study
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New England Water Science Center
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Preliminary machine learning models of manganese and 1,4-dioxane in groundwater on Long Island, New York

Manganese and 1,4-dioxane in groundwater underlying Long Island, New York, were modeled with machine learning methods to demonstrate the use of these methods for mapping contaminants in groundwater in the Long Island aquifer system. XGBoost, a gradient boosted, ensemble tree method, was applied to data from 910 wells for manganese and 553 wells for 1,4-dioxane. Explanatory variables included soil
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Leslie A. DeSimone
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Water Resources Mission Area, New England Water Science Center

Surface-water-quality data to support implementation of revised freshwater aluminum water-quality criteria in Massachusetts, 2018–19

The U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, performed a study to inform the development of the department’s guidelines for the collection and use of water-chemistry data to support calculation of site-dependent aluminum criteria values. The U.S. Geological Survey collected and analyzed discrete water-quality samples at four wastewater-t
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David S. Armstrong, Jennifer G. Savoie, Leslie A. DeSimone, Kaitlin L. Laabs, Richard O. Carey
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Water Resources Mission Area, New England Water Science Center

Manganese in the Northern Atlantic Coastal Plain aquifer system, eastern USA—Modeling regional occurrence with pH, redox, and machine learning

Study region: The study was conducted in the Northern Atlantic Coastal Plain aquifer system, eastern USA, an important water supply in a densely populated region.Study focus: Manganese (Mn), an emerging health concern and common nuisance contaminant in drinking water, is mapped and modeled using the XGBoost machine learning method, predictions of pH and redox conditions from previous models, and o
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Leslie A. DeSimone, Katherine Marie Ransom
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Water Resources Mission Area, California Water Science Center, New England Water Science Center

Machine-learning models to map pH and redox conditions in groundwater in a layered aquifer system, Northern Atlantic Coastal Plain, eastern USA

Study regionThe study was conducted in the Northern Atlantic Coastal Plain aquifer system, in the eastern USA.Study focusGroundwater pH and redox conditions are fundamental chemical characteristics controlling the distribution of many contaminants of concern for drinking water or the ecological health of receiving waters. In this study, pH and redox conditions were modeled and mapped in a complex,
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Leslie A. DeSimone, Jason P. Pope, Katherine Marie Ransom
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Water Resources Mission Area

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 are used to assess the quality of groundwater used for public water supply; land-use study ne
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Terri Arnold, Laura M. Bexfield, MaryLynn Musgrove, Bruce D. Lindsey, Paul E. Stackelberg, Jeannie R. B. Barlow, Leslie A. DeSimone, Justin T. Kulongoski, James A. Kingsbury, Joseph D. Ayotte, Brandon J. Fleming, Kenneth Belitz
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Water Resources Mission Area

Using groundwater age distributions to understand changes in methyl tert-butyl ether (MtBE) concentrations in ambient groundwater, northeastern United States

Temporal changes in methyl tert-butyl ether (MtBE) concentrations in groundwater were evaluated in the northeastern United States, an area of the nation with widespread low-level detections of MtBE based on a national survey of wells selected to represent ambient conditions. MtBE use in the U.S. peaked in 1999 and was largely discontinued by 2007. Six well networks, each representing specific area
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Bruce D. Lindsey, Joseph D. Ayotte, Bryant C. Jurgens, Leslie A. DeSimone
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Water Resources Mission Area, California Water Science Center

Changes in phosphorus concentrations and loads in the Assabet River, Massachusetts, October 2008 through April 2014

Treated effluent discharged from municipal wastewater-treatment plants to the Assabet River in central Massachusetts includes phosphorus, which leads to increased growth of nuisance aquatic plants that decrease the river’s water quality and aesthetics in impounded reaches during the growing season. To improve the river’s water quality and aesthetics, the U.S. Environmental Protection Agency approv
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Jennifer G. Savoie, Leslie A. DeSimone, John R. Mullaney, Marc J. Zimmerman, Marcus C. Waldron
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Water Resources Mission Area, New England Water Science Center

Environmental conditions in the Namskaket Marsh Area, Orleans, Massachusetts: A summary of studies by the U.S. Geological Survey, 1989–2011

Namskaket Marsh and its tidal creek system are potential receptors for a treated wastewater plume originating from a septage treatment facility in the northwest part of Orleans, Massachusetts, on Cape Cod. From 1989 to 2011, the U.S. Geological Survey, in cooperation with State and local partners, conducted a series of studies in the Namskaket Marsh area to characterize the potential effects of th
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Peter K. Weiskel, Jeffrey R. Barbaro, Leslie A. DeSimone
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Water Resources Mission Area, New England Water Science Center

Groundwater quality data from the National Water-Quality Assessment Project, May 2012 through December 2013

Groundwater-quality data were collected from 748 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Program from May 2012 through December 2013. 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, whi
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Terri Arnold, Leslie A. DeSimone, Laura M. Bexfield, Bruce D. Lindsey, Jeannie R. B. Barlow, Justin T. Kulongoski, MaryLynn Musgrove, James A. Kingsbury, Kenneth Belitz
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Water Resources Mission Area, Central Midwest Water Science Center

Methods for evaluating potential sources of chloride in surface waters and groundwaters of the conterminous United States

Chloride exists as a major ion in most natural waters, but many anthropogenic sources are increasing concentrations of chloride in many receiving waters. Although natural concentrations in continental waters can be as high as 200,000 milligrams per liter, chloride concentrations that are suitable for freshwater ecology, human consumption, and agricultural and industrial water uses commonly are on
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Gregory E. Granato, Leslie A. DeSimone, Jeffrey R. Barbaro, Lillian C. Jeznach
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Water Resources Mission Area, New England Water Science Center

Nutrient, suspended sediment, and trace element loads in the Blackstone River Basin in Massachusetts and Rhode Island, 2007 to 2009

Nutrients, suspended sediment, and trace element loads in the Blackstone River and selected tributaries were estimated from composite water-quality samples in order to better understand the distribution and sources of these constituents in the river basin. The flow-proportional composite water-quality samples were collected during sequential 2-week periods at six stations along the river’s main st
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Marc J. Zimmerman, Marcus C. Waldron, Leslie A. DeSimone
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Water Resources Mission Area, New England Water Science Center

The quality of our Nation's waters: Water quality in principal aquifers of the United States, 1991-2010

About 130 million people in the United States rely on groundwater for drinking water, and the need for high-quality drinking-water supplies becomes more urgent as our population grows. Although groundwater is a safe, reliable source of drinking water for millions of people nationwide, high concentrations of some chemical constituents can pose potential human-health concerns. Some of these contamin
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Leslie A. DeSimone, Peter B. McMahon, Michael R. Rosen
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Water Resources Mission Area, Colorado Water Science Center, Water Science School

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