Water Supply and Demand

The Next Generation Water Observing System (NGWOS) provides high-fidelity, real-time data on water quantity, quality, and use to support modern prediction and decision-support systems that are necessary for informing water operations on a daily basis and decision-making during water emergencies. The headwaters of the Colorado and Gunnison River Basins provide an opportunity to implement NGWOS in a...

This website compiles USGS resources and data related to principal aquifers including Aquifer Basics, principal aquifers maps and GIS data, and the National Aquifer Code Reference List.

Declining snow cover is playing a key role in decreasing the flow of the Colorado River, “the lifeblood of the Southwest,” by enabling increased evaporation. As the warming continues, increasingly severe water shortages are expected.

As the USGS Water Resources Mission Area looks to the future, we are updating our water programs to meet 21st century water-resource challenges. As part of these updates, we are integrating the National Water Quality Assessment Project's water-resource monitoring, assessment, trends, modeling, and forecasting activities into new WMA programs.

StreamStats provides access to spatial analytical tools that are useful for water-resources planning and management, and for engineering and design purposes. The map-based user interface can be used to delineate drainage areas, get basin characteristics and estimates of flow statistics, and more. Available information varies from state to state.

From chloride to corrosivity, from pesticides to PAHs, find the most recent National Water Quality Program (NWQP) science on these topics and effects on surface water, groundwater, and ecology. Informative web pages provide an overview and links to related web pages, publications, maps, news, and data.

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)...