Megan Shoda is a Hydrologist with the Water Mission Area Earth System Processes Division.
Meg's research interests include understanding how water quality affects water supply, enhancing the efficiency and productivity of working with large datasets, and creating communication products that deliver the expertise of the USGS in an accessible way.
Education and Certifications
M.S., Biology, University of Dayton
Science and Products
Integrated Water Availability Assessments: Delaware River Basin
Integrated Water Availability Assessments examine water supply, use, and availability. In the Delaware River Basin, which serves over 13 million people, water availability can be affected by drought, river temperature, salinity, and more. The Delaware River Basin IWAAs will investigate these and other water quantity, quality, and use issues to assess available water and how it changes over time.
Pesticides
About 1 billion pounds of conventional pesticides are used each year in the United States to control weeds, insects, and other pests. The use of pesticides has resulted in a range of benefits, including increased food production and reduction of insect-borne disease, but also raises questions about possible adverse effects on the environment, including water quality. The National Water Quality...
Indiana National Water-Quality Assessment Project
Staff have been sampling Sugar Creek at New Palestine and the White River at Hazleton heavily since the USGS National Water-Quality Assessment Program (NAWQA) pilot study in 1991. We have collected 26 years of nutrient, pesticide, major ions, and sediment data at these sites. Our intensive data collection is critical to the science and results published by the NAWQA program.
Surface Water Pesticide Detection Frequency and Benchmark Exceedance Data for the Conterminous United States, 2013-2017
This product consists of pesticide detections and benchmark exceedances in surface waters. These are time series data representing water years 2013 - 2017 for river sites associated with the U.S. Geological Survey National Water Quality Pesticide Monitoring Program.
Water-quality trends for rivers and streams in the Delaware River Basin using Weighted Regressions on Time, Discharge, and Season (WRTDS) models, Seasonal Kendall Trend (SKT) tests, and multisource data, Water Year 1978-2018
This data release provides water-quality trends for rivers and streams in the Delaware River Basin determined using the Weighted Regressions on Time, Discharge, and Season (WRTDS) model and the Seasonal Kendall Trend (SKT) test. Sixteen water-quality parameters were assessed, including nutrients (ammonia, nitrate, filtered orthophosphate, total nitrogen, total phosphorus, and unfiltered orthophosp
Pesticide Toxicity Index (PTI) and maximum Toxic Unit (TUmax) scores and information for fish, cladocerans, and benthic invertebrates from water samples collected at National Water Quality Network sites during Water Years 2013-2017
During 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, collected water samples year-round from the National Water Quality Network - Rivers and Streams (NWQN) and reported on 221 pesticides at 72 sites across the US in agricultural, developed, and mixed land use watersheds. Pesticide Toxicity Index (PTI) scores, a screening-level tool that uses an additive,
Glyphosate and aminomethylphosphonic acid (AMPA) in National Water Quality Network Streams and Rivers in the U.S., Water Years 2015-2017
The U.S. Geological Survey (USGS) National Water Quality Network - Rivers and Streams (NWQN) is comprised of 110 surface-water monitoring sites designed to track ambient water-quality conditions across the nation. Although numerous constituents, including pesticides, have been collected at many of these sites since 1991, glyphosate and its metabolite aminomethylphosphonic acid (AMPA) were not rout
Multi-source surface-water-quality data and U.S. Geological Survey streamgage match for the Delaware River Basin
Jointly managed by multiple states and the federal government, there are many ongoing efforts to characterize and understand water quality in the Delaware River Basin (DRB). Many State, Federal and non-profit organizations have collected surface-water-quality samples across the DRB for decades and many of these data are available through the National Water Quality Monitoring Council's Water Qualit
Replicate surface water and groundwater data analyzed by USGS National Water Quality Laboratory schedule 2437, 2013-15
Replicate water-quality samples are collected and prepared in the field and analyzed in the laboratory in identical ways so that they are considered to be the same in composition and analysis (Mueller and others, 2015). This data set includes one table of duplicate National Water-Quality Assessment Project (NAWQA) surface water and groundwater samples collected between October 1, 2012 and Septembe
Filter Total Items: 13
Water-quality trends in the Delaware River Basin calculated using multisource data and two methods for trend periods ending in 2018
Many organizations in the Delaware River Basin (DRB) monitor surface-water quality for regulatory, scientific, and decision-making purposes. In support of these purposes, over 260,000 water-quality records provided by 8 different organizations were compiled, screened, and used to generate water-quality trends in the DRB. These trends, for periods of record that end in 2018, were generated for 124
Pesticides in US Rivers: Regional differences in use, occurrence, and environmental toxicity, 2013 to 2017
Pesticides pose a threat to the environment, but because of the substantial number of compounds, a comprehensive assessment of pesticides and an evaluation of the risk that they pose to human and aquatic life is challenging. In this study, improved analytical methods were used to quantify 221 pesticide concentrations in surface waters over the time period from 2013 to 2017. Samples were collected
Pesticide mixtures show potential toxicity to aquatic life in U.S. streams, water years 2013-2017
During water years (WY) 2013–2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network – Rivers and Streams (NWQN) year-round and reported on 221 pesticides at 72 sites across the United States in agricultural, developed, and mixed land use watersheds. The Pesticide Toxicity Index (PTI) was used to estimate the potential chronic
A historical look at changing water quality in the Delaware River basin
In 2019 the U.S. Geological Survey (USGS) launched a pilot regional Integrated Water Availability Assessment (IWAA) in the Delaware River Basin (fig. 1). IWAA is intended to explore, test, and refine systems and processes for assessing water availability for human and ecological uses and understanding their underlying controls. Water quality plays an important role in supporting ecological health
Pooling resources across organizations — Multisource water-quality data for the Delaware River Basin
The U.S. Geological Survey (USGS) recently launched a pilot Integrated Water Availability Assessment (IWAA) in the Delaware River Basin to explore, test, and refine systems and processes for assessing water availability for human and ecological uses based on water monitoring data. Water-quality monitoring provides citizens, managers, and scientists with the information needed to evaluate the healt
Influence of land use and region on glyphosate and aminomethylphosphonic acid in streams in the USA
Glyphosate is the most widely used herbicide in the United States for agricultural and non-agricultural weed control. Many studies demonstrate possible effects of glyphosate and its degradate AMPA on human and ecological health. Although glyphosate is thought to have limited mobility in soil, it is found year-round in many rivers and streams throughout the world in both agricultural and developed
Water-quality trends in U.S. rivers, 2002 to 2012: Relations to levels of concern
Effective management and protection of water resources relies upon understanding how water-quality conditions are changing over time. Water-quality trends for ammonia, chloride, nitrate, sulfate, total dissolved solids (TDS), total nitrogen (TN) and total phosphorus (TP) were assessed at 762 sites located in the conterminous United States between 2002 and 2012. Annual mean concentrations at the st
Data analysis considerations for pesticides determined by National Water Quality Laboratory schedule 2437
In 2013, the U.S. Geological Survey National Water Quality Laboratory (NWQL) made a new method available for the analysis of pesticides in filtered water samples: laboratory schedule 2437. Schedule 2437 is an improvement on previous analytical methods because it determines the concentrations of 225 fungicides, herbicides, insecticides, and associated degradates in one method at similar or lower co
Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams
Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013. In weekly
Prediction of pesticide toxicity in Midwest streams
The occurrence of pesticide mixtures is common in stream waters of the United States, and the impact of multiple compounds on aquatic organisms is not well understood. Watershed Regressions for Pesticides (WARP) models were developed to predict Pesticide Toxicity Index (PTI) values in unmonitored streams in the Midwest and are referred to as WARP-PTI models. The PTI is a tool for assessing the rel
Real-time, continuous water-quality monitoring in Indiana and Kentucky
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Indiana and Kentucky. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS scientist
A summary of the benthic-invertebrate and fish-community data from streams in the Indianapolis metropolitan area, Indiana, 1981-2012
Intermittently, during 1981–2012, the U.S. Geological Survey sampled sites in the White River and several tributaries in the Indianapolis metropolitan area of Indiana for benthic invertebrates and fish communities. During 1981–87, one study focused on benthic-invertebrate data collection at three sites along the White River. During 1994–96, 21 sites were sampled for benthic invertebrates; after 19
Science and Products
- Science
Integrated Water Availability Assessments: Delaware River Basin
Integrated Water Availability Assessments examine water supply, use, and availability. In the Delaware River Basin, which serves over 13 million people, water availability can be affected by drought, river temperature, salinity, and more. The Delaware River Basin IWAAs will investigate these and other water quantity, quality, and use issues to assess available water and how it changes over time.Pesticides
About 1 billion pounds of conventional pesticides are used each year in the United States to control weeds, insects, and other pests. The use of pesticides has resulted in a range of benefits, including increased food production and reduction of insect-borne disease, but also raises questions about possible adverse effects on the environment, including water quality. The National Water Quality...Indiana National Water-Quality Assessment Project
Staff have been sampling Sugar Creek at New Palestine and the White River at Hazleton heavily since the USGS National Water-Quality Assessment Program (NAWQA) pilot study in 1991. We have collected 26 years of nutrient, pesticide, major ions, and sediment data at these sites. Our intensive data collection is critical to the science and results published by the NAWQA program. - Data
Surface Water Pesticide Detection Frequency and Benchmark Exceedance Data for the Conterminous United States, 2013-2017
This product consists of pesticide detections and benchmark exceedances in surface waters. These are time series data representing water years 2013 - 2017 for river sites associated with the U.S. Geological Survey National Water Quality Pesticide Monitoring Program.Water-quality trends for rivers and streams in the Delaware River Basin using Weighted Regressions on Time, Discharge, and Season (WRTDS) models, Seasonal Kendall Trend (SKT) tests, and multisource data, Water Year 1978-2018
This data release provides water-quality trends for rivers and streams in the Delaware River Basin determined using the Weighted Regressions on Time, Discharge, and Season (WRTDS) model and the Seasonal Kendall Trend (SKT) test. Sixteen water-quality parameters were assessed, including nutrients (ammonia, nitrate, filtered orthophosphate, total nitrogen, total phosphorus, and unfiltered orthophospPesticide Toxicity Index (PTI) and maximum Toxic Unit (TUmax) scores and information for fish, cladocerans, and benthic invertebrates from water samples collected at National Water Quality Network sites during Water Years 2013-2017
During 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, collected water samples year-round from the National Water Quality Network - Rivers and Streams (NWQN) and reported on 221 pesticides at 72 sites across the US in agricultural, developed, and mixed land use watersheds. Pesticide Toxicity Index (PTI) scores, a screening-level tool that uses an additive,Glyphosate and aminomethylphosphonic acid (AMPA) in National Water Quality Network Streams and Rivers in the U.S., Water Years 2015-2017
The U.S. Geological Survey (USGS) National Water Quality Network - Rivers and Streams (NWQN) is comprised of 110 surface-water monitoring sites designed to track ambient water-quality conditions across the nation. Although numerous constituents, including pesticides, have been collected at many of these sites since 1991, glyphosate and its metabolite aminomethylphosphonic acid (AMPA) were not routMulti-source surface-water-quality data and U.S. Geological Survey streamgage match for the Delaware River Basin
Jointly managed by multiple states and the federal government, there are many ongoing efforts to characterize and understand water quality in the Delaware River Basin (DRB). Many State, Federal and non-profit organizations have collected surface-water-quality samples across the DRB for decades and many of these data are available through the National Water Quality Monitoring Council's Water QualitReplicate surface water and groundwater data analyzed by USGS National Water Quality Laboratory schedule 2437, 2013-15
Replicate water-quality samples are collected and prepared in the field and analyzed in the laboratory in identical ways so that they are considered to be the same in composition and analysis (Mueller and others, 2015). This data set includes one table of duplicate National Water-Quality Assessment Project (NAWQA) surface water and groundwater samples collected between October 1, 2012 and Septembe - Publications
Filter Total Items: 13
Water-quality trends in the Delaware River Basin calculated using multisource data and two methods for trend periods ending in 2018
Many organizations in the Delaware River Basin (DRB) monitor surface-water quality for regulatory, scientific, and decision-making purposes. In support of these purposes, over 260,000 water-quality records provided by 8 different organizations were compiled, screened, and used to generate water-quality trends in the DRB. These trends, for periods of record that end in 2018, were generated for 124Pesticides in US Rivers: Regional differences in use, occurrence, and environmental toxicity, 2013 to 2017
Pesticides pose a threat to the environment, but because of the substantial number of compounds, a comprehensive assessment of pesticides and an evaluation of the risk that they pose to human and aquatic life is challenging. In this study, improved analytical methods were used to quantify 221 pesticide concentrations in surface waters over the time period from 2013 to 2017. Samples were collectedPesticide mixtures show potential toxicity to aquatic life in U.S. streams, water years 2013-2017
During water years (WY) 2013–2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network – Rivers and Streams (NWQN) year-round and reported on 221 pesticides at 72 sites across the United States in agricultural, developed, and mixed land use watersheds. The Pesticide Toxicity Index (PTI) was used to estimate the potential chronicA historical look at changing water quality in the Delaware River basin
In 2019 the U.S. Geological Survey (USGS) launched a pilot regional Integrated Water Availability Assessment (IWAA) in the Delaware River Basin (fig. 1). IWAA is intended to explore, test, and refine systems and processes for assessing water availability for human and ecological uses and understanding their underlying controls. Water quality plays an important role in supporting ecological healthPooling resources across organizations — Multisource water-quality data for the Delaware River Basin
The U.S. Geological Survey (USGS) recently launched a pilot Integrated Water Availability Assessment (IWAA) in the Delaware River Basin to explore, test, and refine systems and processes for assessing water availability for human and ecological uses based on water monitoring data. Water-quality monitoring provides citizens, managers, and scientists with the information needed to evaluate the healtInfluence of land use and region on glyphosate and aminomethylphosphonic acid in streams in the USA
Glyphosate is the most widely used herbicide in the United States for agricultural and non-agricultural weed control. Many studies demonstrate possible effects of glyphosate and its degradate AMPA on human and ecological health. Although glyphosate is thought to have limited mobility in soil, it is found year-round in many rivers and streams throughout the world in both agricultural and developedWater-quality trends in U.S. rivers, 2002 to 2012: Relations to levels of concern
Effective management and protection of water resources relies upon understanding how water-quality conditions are changing over time. Water-quality trends for ammonia, chloride, nitrate, sulfate, total dissolved solids (TDS), total nitrogen (TN) and total phosphorus (TP) were assessed at 762 sites located in the conterminous United States between 2002 and 2012. Annual mean concentrations at the stData analysis considerations for pesticides determined by National Water Quality Laboratory schedule 2437
In 2013, the U.S. Geological Survey National Water Quality Laboratory (NWQL) made a new method available for the analysis of pesticides in filtered water samples: laboratory schedule 2437. Schedule 2437 is an improvement on previous analytical methods because it determines the concentrations of 225 fungicides, herbicides, insecticides, and associated degradates in one method at similar or lower coComplex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams
Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013. In weeklyPrediction of pesticide toxicity in Midwest streams
The occurrence of pesticide mixtures is common in stream waters of the United States, and the impact of multiple compounds on aquatic organisms is not well understood. Watershed Regressions for Pesticides (WARP) models were developed to predict Pesticide Toxicity Index (PTI) values in unmonitored streams in the Midwest and are referred to as WARP-PTI models. The PTI is a tool for assessing the relReal-time, continuous water-quality monitoring in Indiana and Kentucky
Water-quality “super” gages (also known as “sentry” gages) provide real-time, continuous measurements of the physical and chemical characteristics of stream water at or near selected U.S. Geological Survey (USGS) streamgages in Indiana and Kentucky. A super gage includes streamflow and water-quality instrumentation and representative stream sample collection for laboratory analysis. USGS scientistA summary of the benthic-invertebrate and fish-community data from streams in the Indianapolis metropolitan area, Indiana, 1981-2012
Intermittently, during 1981–2012, the U.S. Geological Survey sampled sites in the White River and several tributaries in the Indianapolis metropolitan area of Indiana for benthic invertebrates and fish communities. During 1981–87, one study focused on benthic-invertebrate data collection at three sites along the White River. During 1994–96, 21 sites were sampled for benthic invertebrates; after 19