Types of Water

This list of national principal aquifer codes and names are fixed values assigned by the National Water Information System (NWIS). Aquifers are identified by a geohydrologic unit code - a three-digit number related to the age of the formation, followed by a 4 or 5 character abbreviation for the geologic unit or aquifer name.

Flood-frequency analysis provides information about the magnitude and frequency of floods based on records of annual maximum instantaneous peak discharges. Accurate flood-frequency estimates, created using consistent and uniformly applied methods, are a key component of any effective flood risk and management program. This is a list of current USGS flood frequency reports published by state.

Powder River rises in the Bighorn Mountains of Wyoming and flows northward through a semi-arid landscape in Wyoming and Montana to the Yellowstone River. The river drains an area of 34,700 square kilometers and has an average discharge of about 500 million cubic meters per year. Cross-channel profile data were collected at 22 sites on the river and its tributaries from 1975 through 2014.

Together with partner organizations, the USGS is involved in data collection, analysis, and synthesis to improve estimates of coastal wetland carbon fluxes. This research will help improve science and data availability across a wide range of topics.

Since 1969, the U.S. Geological Survey has maintained a research project in the San Francisco Bay-Delta system to measure and understand how estuarine systems and tidal river deltas function and change in response to hydro-climatic variability and human activities.

In 2019, the USGS began studying the baseline water-quality of selected transboundary rivers in the Pacific Northwest. These studies are designed to characterize current water-quality conditions so as to facilitate future assessments of potential impacts related to upstream mining activities.

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.

USGS water-related projects of international interest.

SPARROW mappers are interactive tools that allow the user to explore river streamflow and nutrient and sediment loads and yields and the importance of different sources of contaminants in a particular river basin. Data can be visualized using maps and interactive graphs and tables, and rankings can be shown by state, major watershed, hydrologic unit (HUC), and catchment.

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.

For 43 years, the Shingobee Headwaters Aquatic Ecosystems Project (SHAEP) brought together scientists from the USGS along with students and professors from universities in Minnesota, North Dakota, Wisconsin, and California to study the physical, chemical, and biological processes of lakes, wetlands, and streams at local and watershed scales. In early 2022, The University of Minnesota and Bemidji...

New projects from coast to coast will advance the research on harmful algal blooms (HABs) in lakes, reservoirs and rivers. The vivid emerald-colored algal blooms are caused by cyanobacteria, which can produce cyanotoxins that threaten human health and aquatic ecosystems and can cause major economic damage.