Is water quality getting better or worse? Answering this deceptively simple question has been a fundamental objective of the USGS National Water-Quality Assessment Project’s research. Learn about trends in contaminants in the nation’s streams and rivers, trends in contaminants that collect in the bed sediment of streams and lakes, and changes in the quality of the nation’s groundwater.
Changes in Water Quality of U.S. Rivers
Human activities have markedly changed the water quality of rivers in the past few decades according to a new study by the U.S. Geological Survey—concentrations of some water-quality constituents have increased while others have decreased.
Suspended Sediment in Streams Decreasing
Concentrations of suspended sediment in many streams are decreasing, reports a new study by the USGS National Water Quality Program. Changes in land management are largely responsible.
In 1991, Congress established the National Water-Quality Assessment (NAWQA) Project to address where, when, why, and how the Nation's water quality has changed, or is likely to change in the future, in response to human activities and natural factors. In response, the NAWQA Project developed multi-pronged approaches to characterize trends in diverse contaminants in the Nation’s streams, rivers, bed sediment, and groundwater.
Trends in Contaminant Concentrations and Loads in the Nation’s Streams and Rivers
The NAWQA Project, other USGS programs, and other Federal, State, and local agencies have collected years of water-quality data to support their assessments of changing water-quality conditions. For the first time, all of these data have been combined to support the most comprehensive assessment conducted to date of water-quality trends in the United States. Collectively, these data provide insight into how natural features and human activities have contributed to water-quality changes over time in Nation's streams and rivers. Data are updated annually. The online Water-Quality Trends mapping tool allows users to visualize trends in water chemistry (nutrients, pesticides, sediment, carbon, and salinity) and aquatic ecology (fish, invertebrates, and algae)
Trends in Sediment-Associated Contaminants
Many contaminants adhere, or sorb, to sediment, so that standard water-quality sampling and analysis is often unable to detect changes in their concentrations over time. Sediment-associated contaminants include legacy contaminants, such as DDT and PCBs, and contaminants currently released into the environment, such as the pesticide bifenthrin and polycyclic aromatic hydrocarbons (PAHs). An alternative approach to determine trends in concentrations of these contaminants is the use of sediment cores collected from lakes and reservoirs.
Changes in Groundwater Quality
USGS scientists are characterizing groundwater quality in principal aquifers, the primary source of the Nation's groundwater used for drinking. Users can access an online tool to see how concentrations of pesticides, nutrients, metals, and organic contaminants in groundwater are changing during decadal periods across the Nation, and see in real time how chemical properties of groundwater at some sites are fluctuating.
Follow the links below to learn more about the quality of the Nation’s streams, rivers, and groundwater and how it’s changing.
National Water-Quality Assessment (NAWQA)
Water Quality in the Nation’s Streams and Rivers – Current Conditions and Long-Term Trends
Groundwater Quality—Current Conditions and Changes Through Time
Water-Quality Trends From Lake Cores
- Overview
Is water quality getting better or worse? Answering this deceptively simple question has been a fundamental objective of the USGS National Water-Quality Assessment Project’s research. Learn about trends in contaminants in the nation’s streams and rivers, trends in contaminants that collect in the bed sediment of streams and lakes, and changes in the quality of the nation’s groundwater.
Changes in Water Quality of U.S. Rivers
Human activities have markedly changed the water quality of rivers in the past few decades according to a new study by the U.S. Geological Survey—concentrations of some water-quality constituents have increased while others have decreased.
Suspended Sediment in Streams Decreasing
Concentrations of suspended sediment in many streams are decreasing, reports a new study by the USGS National Water Quality Program. Changes in land management are largely responsible.
In 1991, Congress established the National Water-Quality Assessment (NAWQA) Project to address where, when, why, and how the Nation's water quality has changed, or is likely to change in the future, in response to human activities and natural factors. In response, the NAWQA Project developed multi-pronged approaches to characterize trends in diverse contaminants in the Nation’s streams, rivers, bed sediment, and groundwater.
Trends in Contaminant Concentrations and Loads in the Nation’s Streams and Rivers
The NAWQA Project, other USGS programs, and other Federal, State, and local agencies have collected years of water-quality data to support their assessments of changing water-quality conditions. For the first time, all of these data have been combined to support the most comprehensive assessment conducted to date of water-quality trends in the United States. Collectively, these data provide insight into how natural features and human activities have contributed to water-quality changes over time in Nation's streams and rivers. Data are updated annually. The online Water-Quality Trends mapping tool allows users to visualize trends in water chemistry (nutrients, pesticides, sediment, carbon, and salinity) and aquatic ecology (fish, invertebrates, and algae)
Sources/Usage: Public Domain.Tributaries contribute to water quality in the Arkansas River, one of hundreds of U.S. streams and rivers where water-quality trends are being monitored. (Credit: Stan Paxton) Trends in Sediment-Associated Contaminants
Many contaminants adhere, or sorb, to sediment, so that standard water-quality sampling and analysis is often unable to detect changes in their concentrations over time. Sediment-associated contaminants include legacy contaminants, such as DDT and PCBs, and contaminants currently released into the environment, such as the pesticide bifenthrin and polycyclic aromatic hydrocarbons (PAHs). An alternative approach to determine trends in concentrations of these contaminants is the use of sediment cores collected from lakes and reservoirs.
Changes in Groundwater Quality
Sources/Usage: Public Domain.Monitoring groundwater quality at a public-supply well. USGS scientists are characterizing groundwater quality in principal aquifers, the primary source of the Nation's groundwater used for drinking. Users can access an online tool to see how concentrations of pesticides, nutrients, metals, and organic contaminants in groundwater are changing during decadal periods across the Nation, and see in real time how chemical properties of groundwater at some sites are fluctuating.
- Science
Follow the links below to learn more about the quality of the Nation’s streams, rivers, and groundwater and how it’s changing.
National Water-Quality Assessment (NAWQA)
Our surface water, groundwater, and aquatic ecosystems are priceless resources, used by people across the Nation for drinking, irrigation, industry, and recreation. The National Water-Quality Assessment (NAWQA) Project is a leading source of scientific data and knowledge for development of science-based policies and management strategies to improve and protect our water resources.Water Quality in the Nation’s Streams and Rivers – Current Conditions and Long-Term Trends
The Nation's rivers and streams are a priceless resource, but pollution from urban and agricultural areas pose a threat to our water quality. To understand the value of water quality, and to more effectively manage and protect the Nation's water resources, it's critical that we know the current status of water-quality conditions, and how and why those conditions have been changing over time.Groundwater Quality—Current Conditions and Changes Through Time
Is groundwater the source of your drinking water? The USGS is assessing the quality of groundwater used for public supply using newly collected data along with existing water-quality data. Learn more about this invisible, vital resource so many of us depend on.Water-Quality Trends From Lake Cores
Sediment cores let us look back in time at the contaminant history of a watershed. Learn about what lake and reservoir sediment cores tell us about trends in metals, organochlorine pesticides, polycyclic aromatic hydrocarbons, and other sediment-related contaminants. - Data
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