Measuring and Monitoring Water

A streamgage is a structure installed beside a stream or river that contains equipment that measures and records the water level (called gage height or stage) of the stream. Streamflow (also called discharge) is computed from measured water levels using a site-specific relation (called a stage-discharge rating curve) developed from onsite water level and streamflow measurements made by USGS...

Since the early 1980s the USGS has worked cooperatively with manufacturers to develop and enhance the use of acoustic Doppler instruments for streamflow and other hydraulic measurements. This site provides information on hydroacoustic technology, instruments, and their use.

Like people, plants need nutrients, but too much of a good thing can be a problem. Nutrients, such as nitrogen and phosphorus, occur naturally, but most of the nutrients in our waterways come from human activities and sources—fertilizers, wastewater, automobile exhaust, animal waste. The USGS investigates the source, transport, and fate of nutrients and their impacts on the world around us.

Wherever you live, there’s a creek or stream near you. The eighty percent of Americans who live in metropolitan areas are often unaware of the network of urban creeks—many teeming with life—that weaves through our cities and town. Nowhere are the environmental changes associated with urban development more evident than in urban streams.

The USGS is evaluating the integration of small unoccupied aircraft systems – sUAS or "drones" – into USGS hydrogeophysical studies. The following projects are part of a Water Resources Mission Area demonstration and evaluation effort in collaboration with USGS Water Science Centers (WSCs) starting in June 2018.

Data scientists in the USGS Water Resources Mission Area make sense of large environmental and operational datasets by applying various modeling, statistical, and visualization techniques to generate actionable information.

The enhanced probability of catastrophic wildfires has increased our need to understand the risk of floods, erosion, and debris and contaminant transport in burned watersheds. This project investigates the relation between rainfall intensity and peak discharge; erosion and deposition processes; and water-quality impacts to minimize the loss of life and property resulting from post-wildfire floods.

In 1954, the U.S. Supreme Court issued a Decree in State of New Jersey v. State of New York and City of New York in which the Court established the position of the Delaware River Master.

The USGS has estimated water use for the United States every 5 years since 1950. Estimates are provided for groundwater and surface-water sources, for fresh and saline water quality, and by sector or category of use. Estimates have been made at the State level since 1950, and at the county level since 1985. Water-use estimates by watershed were made from 1950 through 1995, first at the water...

Total withdrawals for all categories of use in 2015 were estimated to be 322 billion gallons per day (Bgal/d), a level of withdrawal not reported since before 1970. Total withdrawals in 2015 were 9 percent less than in 2010, continuing a sharp but steady downward trend since 2005. Freshwater withdrawals were also 9 percent less than in 2015.

Surface-water sources include streams and rivers, lakes and reservoirs, and oceans. For the purposes of the USGS water-use reports, surface water with less than 1,000 milligrams per liter (mg/L) of dissolved solids is considered freshwater, and the remainder is considered saline. Surface-water resources are often evaluated by watershed. The most recent USGS water-use estimates by watershed are in...

Groundwater refers to all subsurface water, specifically that part of groundwater which is in the saturated zone. Groundwater sources are called aquifers: geologic formations that contain sufficient saturated permeable material to yield significant quantities of water to wells and springs. For the purposes of the USGS water-use reports, groundwater with less than 1,000 milligrams per liter (mg/L)...