Water Resources

Filter Total Items: 436
Date published: July 22, 2021
Status: Completed

About the USGS National Brackish Groundwater Assessment

The objectives of the National Brackish Groundwater Assessment were to identify and characterize aquifers that contain brackish groundwater in the United States. For purposes of this study, brackish groundwater is defined as having dissolved solids at concentrations between 1,000 and 10,000 milligrams per liter.

Attribution: Water Resources
Date published: July 22, 2021
Status: Completed

National Brackish Groundwater Assessment: Sources of Dissolved Solids in Brackish Groundwater

A variety of conditions and mechanisms can cause groundwater to become brackish. An understanding of the sources of dissolved solids that contribute to the formation of brackish groundwater can help determine where brackish aquifers are likely to exist and can provide clues about other characteristics, such as the chemical composition, of brackish aquifers.

Attribution: Water Resources
Date published: July 22, 2021
Status: Completed

National Brackish Groundwater Assessment: How is Brackish Groundwater Being Used?

Industry and public drinking-water suppliers are increasingly turning to brackish groundwater to supplement or replace the use of freshwater. Brackish groundwater is either directly used or treated.

Attribution: Water Resources
Date published: July 22, 2021
Status: Completed

National Brackish Groundwater Assessment: Pilot Saline Studies

Three pilot studies were conducted (2010-2012) to assess saline groundwater resources at regional scales. The goals of the pilot studies were to determine the availability of data for assessing the distribution and character of saline groundwater and test and develop methodologies for assessing the resource.

Attribution: Water Resources
Date published: July 22, 2021
Status: Completed

National Brackish Groundwater Assessment: Previous Work

Interest in the distribution and classification of brackish groundwater for use as a source of water supply has been longstanding. These studies provided valuable background for the National Brackish Groundwater Assessment.

Attribution: Water Resources
Date published: July 20, 2021
Status: Active

Groundwater-Level Response to Earthquakes

Did you know that earthquakes can cause changes in groundwater levels? Very large earthquakes can even cause water-level fluctuations in some wells thousands of miles away, depending on the local geological conditions around the well.

Attribution: Water Resources
Date published: July 20, 2021
Status: Active

Karst Aquifers

Karst terrain is created from the dissolution of soluble rocks, principally limestone and dolomite. Karst areas are characterized by distinctive landforms (like springs, caves, sinkholes) and a unique hydrogeology that results in aquifers that are highly productive but extremely vulnerable to contamination.

Contacts: Allan K Clark
Attribution: Water Resources
Date published: July 20, 2021
Status: Active

Karst Aquifers: Arbuckle-Simpson Aquifer

The Arbuckle-Simpson aquifer, which underlies more than 500 square miles in south central Oklahoma, is the principal water source for approximately 39,000 people in several cities in the region. The U.S. Environmental Protection Agency has designated the aquifer's eastern portion as a Sole Source Aquifer, a mechanism to protect drinking water supplies in areas with limited water supply.

Contacts: Allan K Clark
Attribution: Water Resources
Date published: July 20, 2021
Status: Active

Karst Aquifers: Basin and Range and Bear River Range Carbonate Aquifers

In the Basin and Range, bedrock is present in the uplifted blocks of the mountain ranges and beneath fill in the valleys. While some of this bedrock is relatively impermeable, fracturing may enable groundwater to circulate through the rock, enlarging and increasing the size and number of pathways for water movement. This can ultimately produce a permeable water-yielding unit.

Contacts: Allan K Clark
Attribution: Water Resources
Date published: July 20, 2021
Status: Active

Karst Aquifers: Colorado Plateau Karst

In northern and central Arizona, the Kaibab Limestone and its equivalents are karstic. North of the Grand Canyon, subterranean openings are primarily widely spaced fissures, while south of the Grand Canyon, fissures are more closely spaced and a few shallow caves are present.

Contacts: Allan K Clark
Attribution: Water Resources
Date published: July 20, 2021
Status: Active

Karst Aquifers: Edwards Balcones Fault Zone Aquifer

The Edwards aquifer is the most transmissive of all the aquifers in Texas and Oklahoma, with large discharges from springs and from flowing and pumped wells. This aquifer demonstrates karst features such as springs and in-stream sinkholes, as well as endangered species.

Contacts: Allan K Clark
Attribution: Water Resources
Date published: July 20, 2021
Status: Active

Karst Aquifers: Edwards-Trinity Plateau Aquifer

The Edwards-Trinity aquifer, located in the Trans-Pecos and the Edwards Plateau areas, is composed of relatively flat-lying rocks that are generally exposed at the land surface. This aquifer is generally recharged by precipitation; water is mostly unconfined in the shallow parts of the aquifer and is confined in the deeper zones.

Contacts: Allan K Clark
Attribution: Water Resources