USGS groundwater hydrologist, Bill Eldridge, is lowering a transducer into an observation well near Jewel Cave National Monument to monitor water-level changes in the Madison aquifer. The data collected will be used to update previously published groundwater-altitude maps to help better understand groundwater flow.
What is groundwater?
Groundwater is water that exists underground in saturated zones beneath the land surface. The upper surface of the saturated zone is called the water table.
Contrary to popular belief, groundwater does not form underground rivers. It fills the pores and fractures in underground materials such as sand, gravel, and other rock, much the same way that water fills a sponge. If groundwater flows naturally out of rock materials or if it can be removed by pumping (in useful amounts), the rock materials are called aquifers.
Groundwater moves slowly, typically at rates of 7-60 centimeters (3-25 inches) per day in an aquifer. As a result, water could remain in an aquifer for hundreds or thousands of years. Groundwater is the source of about 40 percent of water used for public supplies and about 39 percent of water used for agriculture in the United States.
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Related Content
How important is groundwater?
Groundwater, which is in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 37 percent of the water that county and city water departments supply to households and businesses (public supply). It provides drinking water for more than 90 percent of the rural population who do not get their water delivered to them from...
How does an earthquake affect groundwater levels and water quality in wells?
Groundwater levels in wells can oscillate up and down when seismic waves pass. The water level might remain higher or lower for a period of time after the seismic waves end, but sometimes a long-term offset of groundwater levels follows an earthquake. The largest recorded earthquake-induced offset in a well is a one meter rise. Water quality can also be affected by earthquakes, typically in...
If the ground filters water, is groundwater always clean?
Water drawn from a well was once precipitation that fell onto Earth's surface. It seeped into the ground and, over time, occupied the porous space in some subsurface material. Big particles that are in surface streams, such as leaf chunks, will not be seen in groundwater. So, yes, big particles are filtered out by the ground, along with some minerals and chemicals that are too small to see. But...
Does the use of pesticides affect our Nation's water quality?
Pesticide use in the United States has increased because not only must we supply our exploding population with food, but crops and food are also grown for export to other countries. The United States has become the largest producer of food products in the world, partly owing to our use of modern chemicals (pesticides) to control the insects, weeds, and other organisms that attack food crops. But...
Where can I get my well water tested?
Some counties offer free well water testing, so check with your county first. If they don't, use this EPA website to find a list of state-certified laboratories in your area that do water testing, or contact your county or state health department or your State Certification Officer for assistance. Prices will vary depending on the laboratory and the test(s), but most people consider the cost to be...
What determines if a well will go dry?
A well is said to have gone dry when water levels drop below a pump intake. This does not mean that a dry well will never have water in it again, as the water level may come back through time as recharge increases. The water level in a well depends on a number of things, such as the depth of the well, the type (confined or unconfined) of aquifer the well taps, the amount of pumping that occurs in...
How much water is used by people in the United States?
Since 1950, the USGS has collected and analyzed water-use data for the United States and its Territories . That data is revised every 5 years. As of 2015, the United States uses 322 billion gallons of water per day (Bgal/day). The three largest water-use categories were irrigation (118 Bgal/day), thermoelectric power (133 Bgal/day), and public supply (39 Bgal/day), cumulatively accounting for 90...
How much natural water is there?
Earth is estimated to hold about 1,386,000,000 cubic kilometers of water. The breakdown of where all that water resides is estimated as follows: Oceans (saline) 1,338,000,000 cubic kilometers Ice caps and glaciers (fresh) 24,064,000 cubic kilometers Groundwater (fresh and saline) 23,400,000 cubic kilometers Streams, lakes, swamps (fresh) 104,590 cubic kilometers Lakes (saline) 85,400 cubic...
How can I find the depth to the water table in a specific location?
The depth to the water table can change (rise or fall) depending on the time of year. During the late winter and spring when accumulated snow starts to melt and spring rainfall is plentiful, water on the surface infiltrates into the ground and the water table rises. When water-loving plants start to grow again in the spring and precipitation gives way to hot, dry summers, the water table falls...
What is the Ground Water Atlas of the United States?
This Ground Water Atlas of the United States is a series of USGS publications that describe the location, the extent, and the geologic and hydrologic characteristics of the important aquifers of the Nation. The series consists of 13 chapters that describe the regional groundwater resources that collectively cover 50 States, Puerto Rico, and the U.S. Virgin Islands. Learn more: Principal Aquifers...
USGS groundwater hydrologist, Bill Eldridge, is lowering a transducer into an observation well near Jewel Cave National Monument to monitor water-level changes in the Madison aquifer. The data collected will be used to update previously published groundwater-altitude maps to help better understand groundwater flow.
Measuring the groundwater level in a well near Lame Deer, Montana
Measuring the groundwater level in a well near Lame Deer, Montana
- Corrosive groundwater, if untreated, can dissolve lead and other metals from pipes.
- National maps have been prepared to identify the occurrence of potentially corrosive groundwater in the U.S.
- These findings have the greatest implication for the 44 million people dependent on domestic wells for drinking water.
- Corrosive groundwater, if untreated, can dissolve lead and other metals from pipes.
- National maps have been prepared to identify the occurrence of potentially corrosive groundwater in the U.S.
- These findings have the greatest implication for the 44 million people dependent on domestic wells for drinking water.
Flowing groundwater site in Indiana
Flowing groundwater site in Indiana
USGS scientist tests groundwater samples for water quality.
USGS scientist tests groundwater samples for water quality.
Setting up Groundwater Streamgage on Green River nr LaBarge
Setting up Groundwater Streamgage on Green River nr LaBarge
--issues facing current and future water supplies
by William Alley, USGS Office of Groundwater
--issues facing current and future water supplies
by William Alley, USGS Office of Groundwater
Real-time Groundwater Streamgage equipment set up
Real-time Groundwater Streamgage equipment set up
Status of water-level altitudes and long-term and short-term water-level changes in the Chicot and Evangeline (undifferentiated) and Jasper aquifers, greater Houston area, Texas, 2023
Water-level and recoverable water in storage changes, High Plains Aquifer, predevelopment to 2019 and 2017 to 2019
Availability of groundwater from the volcanic aquifers of the Hawaiian Islands
Estimated groundwater withdrawals from principal aquifers in the United States, 2015
Water priorities for the nation—The U.S. Geological Survey next generation water observing system
The quality of our Nation's waters: Water quality in principal aquifers of the United States, 1991-2010
Groundwater studies: principal aquifer surveys
The quality of our nation's waters: Nutrients in the nation's streams and groundwater, 1992-2004
Ground-water availability in the United States
Pesticides in the nation's streams and ground water, 1992-2001 - a summary
Sustainability of ground-water resources
Ground water and surface water: A single resource
Related Content
- FAQ
How important is groundwater?
Groundwater, which is in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 37 percent of the water that county and city water departments supply to households and businesses (public supply). It provides drinking water for more than 90 percent of the rural population who do not get their water delivered to them from...
How does an earthquake affect groundwater levels and water quality in wells?
Groundwater levels in wells can oscillate up and down when seismic waves pass. The water level might remain higher or lower for a period of time after the seismic waves end, but sometimes a long-term offset of groundwater levels follows an earthquake. The largest recorded earthquake-induced offset in a well is a one meter rise. Water quality can also be affected by earthquakes, typically in...
If the ground filters water, is groundwater always clean?
Water drawn from a well was once precipitation that fell onto Earth's surface. It seeped into the ground and, over time, occupied the porous space in some subsurface material. Big particles that are in surface streams, such as leaf chunks, will not be seen in groundwater. So, yes, big particles are filtered out by the ground, along with some minerals and chemicals that are too small to see. But...
Does the use of pesticides affect our Nation's water quality?
Pesticide use in the United States has increased because not only must we supply our exploding population with food, but crops and food are also grown for export to other countries. The United States has become the largest producer of food products in the world, partly owing to our use of modern chemicals (pesticides) to control the insects, weeds, and other organisms that attack food crops. But...
Where can I get my well water tested?
Some counties offer free well water testing, so check with your county first. If they don't, use this EPA website to find a list of state-certified laboratories in your area that do water testing, or contact your county or state health department or your State Certification Officer for assistance. Prices will vary depending on the laboratory and the test(s), but most people consider the cost to be...
What determines if a well will go dry?
A well is said to have gone dry when water levels drop below a pump intake. This does not mean that a dry well will never have water in it again, as the water level may come back through time as recharge increases. The water level in a well depends on a number of things, such as the depth of the well, the type (confined or unconfined) of aquifer the well taps, the amount of pumping that occurs in...
How much water is used by people in the United States?
Since 1950, the USGS has collected and analyzed water-use data for the United States and its Territories . That data is revised every 5 years. As of 2015, the United States uses 322 billion gallons of water per day (Bgal/day). The three largest water-use categories were irrigation (118 Bgal/day), thermoelectric power (133 Bgal/day), and public supply (39 Bgal/day), cumulatively accounting for 90...
How much natural water is there?
Earth is estimated to hold about 1,386,000,000 cubic kilometers of water. The breakdown of where all that water resides is estimated as follows: Oceans (saline) 1,338,000,000 cubic kilometers Ice caps and glaciers (fresh) 24,064,000 cubic kilometers Groundwater (fresh and saline) 23,400,000 cubic kilometers Streams, lakes, swamps (fresh) 104,590 cubic kilometers Lakes (saline) 85,400 cubic...
How can I find the depth to the water table in a specific location?
The depth to the water table can change (rise or fall) depending on the time of year. During the late winter and spring when accumulated snow starts to melt and spring rainfall is plentiful, water on the surface infiltrates into the ground and the water table rises. When water-loving plants start to grow again in the spring and precipitation gives way to hot, dry summers, the water table falls...
What is the Ground Water Atlas of the United States?
This Ground Water Atlas of the United States is a series of USGS publications that describe the location, the extent, and the geologic and hydrologic characteristics of the important aquifers of the Nation. The series consists of 13 chapters that describe the regional groundwater resources that collectively cover 50 States, Puerto Rico, and the U.S. Virgin Islands. Learn more: Principal Aquifers...
- Multimedia
Groundwater-Level Measurement near Jewel Cave National Monument, SDGroundwater-Level Measurement near Jewel Cave National Monument, SD
USGS groundwater hydrologist, Bill Eldridge, is lowering a transducer into an observation well near Jewel Cave National Monument to monitor water-level changes in the Madison aquifer. The data collected will be used to update previously published groundwater-altitude maps to help better understand groundwater flow.
USGS groundwater hydrologist, Bill Eldridge, is lowering a transducer into an observation well near Jewel Cave National Monument to monitor water-level changes in the Madison aquifer. The data collected will be used to update previously published groundwater-altitude maps to help better understand groundwater flow.
Measuring the groundwater level in a well near Lame Deer, MontanaMeasuring the groundwater level in a well near Lame Deer, MontanaMeasuring the groundwater level in a well near Lame Deer, Montana
Measuring the groundwater level in a well near Lame Deer, Montana
Potential Corrosivity of Untreated Groundwater in the United StatesPotential Corrosivity of Untreated Groundwater in the United StatesPotential Corrosivity of Untreated Groundwater in the United States- Corrosive groundwater, if untreated, can dissolve lead and other metals from pipes.
- National maps have been prepared to identify the occurrence of potentially corrosive groundwater in the U.S.
- These findings have the greatest implication for the 44 million people dependent on domestic wells for drinking water.
- Corrosive groundwater, if untreated, can dissolve lead and other metals from pipes.
- National maps have been prepared to identify the occurrence of potentially corrosive groundwater in the U.S.
- These findings have the greatest implication for the 44 million people dependent on domestic wells for drinking water.
Flowing groundwater site in IndianaFlowing groundwater site in Indiana
Flowing groundwater site in Indiana
USGS scientist tests groundwater samples for water quality.USGS scientist tests groundwater samples for water quality.USGS scientist tests groundwater samples for water quality.
USGS scientist tests groundwater samples for water quality.
Setting up Groundwater Streamgage on Green River nr LaBargeSetting up Groundwater Streamgage on Green River nr LaBargeSetting up Groundwater Streamgage on Green River nr LaBarge
Setting up Groundwater Streamgage on Green River nr LaBarge
PubTalk 9/2011 — Tracking the Nation's Groundwater ReservesPubTalk 9/2011 — Tracking the Nation's Groundwater ReservesPubTalk 9/2011 — Tracking the Nation's Groundwater Reserves--issues facing current and future water supplies
by William Alley, USGS Office of Groundwater
--issues facing current and future water supplies
by William Alley, USGS Office of Groundwater
Real-time Groundwater Streamgage equipment set upReal-time Groundwater Streamgage equipment set up
Real-time Groundwater Streamgage equipment set up
- Publications
Filter Total Items: 16
Status of water-level altitudes and long-term and short-term water-level changes in the Chicot and Evangeline (undifferentiated) and Jasper aquifers, greater Houston area, Texas, 2023
Since the early 1900s, groundwater withdrawn from the primary aquifers that compose the Gulf Coast aquifer system—the Chicot, Evangeline, and Jasper aquifers—has been an important source of water in the greater Houston area, Texas. This report, prepared by the U.S. Geological Survey in cooperation with the Harris-Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, Lone SAuthorsJason K. RamageWater-level and recoverable water in storage changes, High Plains Aquifer, predevelopment to 2019 and 2017 to 2019
The High Plains aquifer underlies 111.8 million acres (about 175,000 square miles) in parts of eight States: Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. Water-level declines began in parts of the High Plains aquifer soon after the beginning of substantial groundwater irrigation (about 1950). This report presents water-level changes and change in recoverableAuthorsVirginia L. McGuire, Kellan R. StrauchAvailability of groundwater from the volcanic aquifers of the Hawaiian Islands
The islands of Hawaiʻi were built by basaltic shield volcanoes in the Pacific Ocean. These volcanoes formed aquifers that supply hundreds of millions of gallons of fresh water per day to the islands’ residents and diverse industries. Groundwater discharge from the volcanic aquifers to streams and the coast also supports traditional practices and ecosystems. The aquifers' capacity to yield fresh grAuthorsScot K. Izuka, Kolja RotzollEstimated groundwater withdrawals from principal aquifers in the United States, 2015
In 2015, about 84,600 million gallons per day (Mgal/d) of groundwater were withdrawn in the United States for various uses including public supply, self-supplied domestic, industrial, mining, thermoelectric power, aquaculture, livestock, and irrigation. Of this total, about 94 percent (79,200 Mgal/d) was withdrawn from principal aquifers, which are defined as regionally extensive aquifers or aquifAuthorsJohn K. Lovelace, Martha G. Nielsen, Amy L. Read, Chid J. Murphy, Molly A. MaupinWater priorities for the nation—The U.S. Geological Survey next generation water observing system
The challenges of providing safe and sustainable water supplies for human and ecological uses and protecting lives and property during water emergencies are well recognized. The U.S. Geological Survey (USGS) plays an essential role in meeting these challenges through its observational networks and renowned water science and research activities (National Academies of Science, Engineering, and MedicAuthorsSandra M. Eberts, Chad R. Wagner, Michael D. WoodsideThe quality of our Nation's waters: Water quality in principal aquifers of the United States, 1991-2010
About 130 million people in the United States rely on groundwater for drinking water, and the need for high-quality drinking-water supplies becomes more urgent as our population grows. Although groundwater is a safe, reliable source of drinking water for millions of people nationwide, high concentrations of some chemical constituents can pose potential human-health concerns. Some of these contaminAuthorsLeslie A. DeSimone, Peter B. McMahon, Michael R. RosenGroundwater studies: principal aquifer surveys
In 1991, the U.S. Congress established the National Water-Quality Assessment (NAWQA) program within the U.S. Geological Survey (USGS) to develop nationally consistent long-term datasets and provide information about the quality of the Nation’s streams and groundwater. The USGS uses objective and reliable data, water-quality models, and systematic scientific studies to assess current water-qualityAuthorsKaren R. Burow, Kenneth BelitzThe quality of our nation's waters: Nutrients in the nation's streams and groundwater, 1992-2004
National Findings and Their ImplicationsAlthough the use of artificial fertilizer has supported increasing food production to meet the needs of a growing population, increases in nutrient loadings from agricultural and, to a lesser extent, urban sources have resulted in nutrient concentrations in many streams and parts of aquifers that exceed standards for protection of human health and (or) aquatAuthorsNeil M. Dubrovsky, Karen R. Burow, Gregory M. Clark, JoAnn M. Gronberg, Pixie A. Hamilton, Kerie J. Hitt, David K. Mueller, Mark D. Munn, Bernard T. Nolan, Larry J. Puckett, Michael G. Rupert, Terry M. Short, Norman E. Spahr, Lori A. Sprague, William G. WilberGround-water availability in the United States
Ground water is among the Nation's most important natural resources. It provides half our drinking water and is essential to the vitality of agriculture and industry, as well as to the health of rivers, wetlands, and estuaries throughout the country. Large-scale development of ground-water resources with accompanying declines in ground-water levels and other effects of pumping has led to concernsAuthorsThomas E. Reilly, Kevin F. Dennehy, William M. Alley, William L. CunninghamPesticides in the nation's streams and ground water, 1992-2001 - a summary
No abstract available.AuthorsRobert J. Gilliom, Pixie A. HamiltonSustainability of ground-water resources
The pumpage of fresh ground water in the United States in 1995 was estimated to be approximately 77 billion gallons per day (Solley and others, 1998), which is about 8 percent of the estimated 1 trillion gallons per day of natural recharge to the Nation's ground-water systems (Nace, 1960). From an overall national perspective, the ground-water resource appears ample. Locally, however, the availabiAuthorsWilliam M. Alley, Thomas E. Reilly, O. Lehn FrankeGround water and surface water: A single resource
The importance of considering ground water and surface water as a single resource has become increasingly evident. Issues related to water supply, water quality, and degradation of aquatic environments are reported on frequently. The interaction of ground water and surface water has been shown to be a significant concern in many of these issues. Contaminated aquifers that discharge to streams canAuthorsThomas C. Winter, Judson W. Harvey, O. Lehn Franke, William M. Alley - News