Water Resources

Measuring and Monitoring Water

Hydrologic Instrumentation Facility (HIF)

Hydrologic Instrumentation Facility (HIF)

The HIF provides quality hydrologic equipment and instrumentation

Learn More

Streamgaging Basics

Streamgaging Basics

The USGS has a nationwide network of over 8,500 sites that measure streamflow and water levels.

Learn More
Filter Total Items: 159
Date published: February 27, 2019
Status: Active

Volatile Organic Compounds (VOCs)

Volatile organic compounds (VOCs) are chemicals that both vaporize into air and dissolve in water. VOCs are pervasive in daily life, because they’re used in industry, agriculture, transportation, and day-to-day activities around the home. Once released into groundwater, many VOCs are persistent and can migrate to drinking-water supply wells.

Contacts: Bruce Lindsey
Date published: February 27, 2019
Status: Active

Oxidation/Reduction (Redox)

The redox state of groundwater—whether the groundwater is oxic (oxidized) or anoxic (reduced)—has profound implications for groundwater quality.  Knowing the redox conditions of groundwater can help determine whether it contains elevated levels of many contaminants, including arsenic, nitrate, and even some manmade contaminants.

Contacts: Peter B McMahon
Date published: February 27, 2019
Status: Active

Everything you need to know about SPARROW

What is SPARROW? SPARROW (SPAtially Referenced Regression On Watershed attributes) is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds such as contaminant sources and environmental factors that affect rates of delivery to streams and in-stream processing. The core of the model...

Date published: February 27, 2019
Status: Completed

National Water-Quality Assessment (NAWQA): 1991-2012

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. This page discusses the first two decadal cycles of NAWQA research from 1991 through 2012.

Date published: February 27, 2019
Status: Active

Linking Selenium Sources to Ecosystems: Modeling

Selenium (Se) as a contaminant of ecosystems is bioaccumulative and causes reproductive effects in fish and wildlife. Ecosystem-scale Se modeling predicts Se bioaccumulation based on dietary biodynamics within site-specific food webs. The model can be used to forecast Se toxicity under different management or regulatory proposals or to translate a tissue guideline to a dissolved guideline. ...

Contacts: Theresa Presser, Joseph P. Skorupa
Attribution: Water Resources
Date published: February 27, 2019
Status: Active

Water-Use Terminology

The following terms have been used in one or more of the water-use publications. The ...

Date published: February 26, 2019
Status: Active

Flood Inundation Map (FIM) Libraries

The Flood Inundation Mapping Program focuses on developing flood inundation map libraries and helping communities pair those libraries with real-time stream data and National Weather Service flood forecasts to form a two-dimensional flood warning system. Together, these products can help communities estimate the extent of a flood and identify at-risk areas and resources in advance of...

Attribution: Water Resources
Date published: February 26, 2019
Status: Completed

National Brackish Groundwater Assessment

All water naturally contains dissolved solids that can make it "brackish" or distastefully salty. The amount of freshwater for drinking-water, agricultural, industrial, and environmental needs has declined in many areas and has led to concerns about future availability. The USGS conducted a national assessment of brackish aquifers that could supplement or replace freshwater sources.

Attribution: Water Resources
Date published: February 26, 2019
Status: Active

Emerging Flood Inundation Mapping Technologies

The following technologies represent state-of-the-art tools, methodologies, and techniques that the USGS and our partners are researching and testing. Most of these techniques are experimental and not publicly available, but could significantly improve our ability to plan for and respond to flooding events in the future.

Attribution: Water Resources
Date published: February 25, 2019
Status: Completed

2011 - The Year of the Flood

2011 proved to be another record-breaking flood year in the United States. USGS Water Science Center personnel from North Dakota to Louisiana measured springtime floods on the Red River of the North, the Ohio River, the Mississippi River, and many tributaries. The Missouri River and its tributaries saw record-breaking snow-melt runoff through the summer, followed closely by Hurricane Irene and...

Date published: February 25, 2019
Status: Active

Water-Quality Quick Links

Looking for data? Maps? Use the links below to quickly access some of the most frequently visited USGS web pages on water quality.

Contacts: Barbara Mahler
Date published: February 25, 2019
Status: Active

Urban Waters Federal Partnership—Bronx and Harlem River Watersheds (New York, N.Y.)

The Harlem and Bronx Rivers provide ecological and social resources in an intensively urban area. Connecting people to rivers requires clean water—the USGS is helping to assess the efficacy of green infrastructure to improve the quality of stormwater that flows into the rivers.