Groundwater

Groundwater is the water found underground in the cracks and spaces in soil, sand, and rock. Groundwater has been used by humans for thousands of years; today it provides 25% of the fresh water used in the United States, mostly for irrigation and public water supplies.

Basics

Water well in New York. Image Credit: Wikimedia Commons user Wknight94

Groundwater is an inevitable result of gravity: if surface water can seep into the ground before it evaporates or flows away, it will. Water also flows through rocks underground and may flow out of the ground into streams, rivers, lakes, or the ocean in places where the land surface is lower than the water table (e.g., at the bottom of a valley or the side of a cliff) – these outflows of groundwater are commonly called “springs”. In this way, surface water and groundwater are intimately linked – in some places, changes in groundwater levels can have major effects on the levels of nearby rivers and lakes, and vice versa.   Read more

Frequently Asked Questions

Latest News

U.S. Geological Survey's (USGS) map of groundwater depletion
(2017-03-06)
It's Groundwater Awareness Week 2017 (#GWAwarenessWeek if you're on twitter)! Today's Critical Issues Map of the Day from the USGS and shows the cumulative depletion of groundwater for 40 aquifer systems across the U.S (excluding Alaska). The map depicts depletion over the time period of 1900 to...
Atlean Lake in British Columbia
(2016-11-29)
November 10, 2016 The U.S. Geological Survey (USGS) has announced a new grant program that will award up to $2 million in cooperative agreements for new state and local water resource agencies participating in the National Groundwater Monitoring Network (NGWMN). The funds will be used to provide...
Hawaiian flower
(2016-11-03)
October 18, 2016 On October 18, the Senate Committee on Energy and Natural Resources held a hearing at the Hawaiian State Capitol in Honolulu. The hearing addressed current water resource scarcity issues facing the state and recent water legislation. Hawaii‘s freshwater supplies are drawn almost...
Irrigation equipment. (Background: Copyright Shutterstock.com/Sergey Nivens; right: Copyright Shutterstock.com/Cecilia Lim H M)
(2016-10-28)
The 2016 Critical Issues Forum, Addressing Changes in Regional Groundwater Resources: Lessons from the High Plains Aquifer concluded today at the Colorado School of Mines Ben H. Parker Student Center. An initial summary of social media posts using #CIForum16 were compiled connecting people to...
Interactive map of water wells in Nebraska. Image Credit: Nebraska Department of Natural Resources
(2016-10-14)
#MapOfTheDay! Today the Critical Issues Program (@AGI_GeoIssues) shared an interactive map of water wells in Nebraska from the Nebraska Department of Natural Resources (@NebraskaDNR), which you can find at bit.ly/22dbeyi. For more information on groundwater issues in the High Plains, consider...
Interactive Map of Water Resources in Georgia
(2016-09-15)
#MapOfTheDay! Today the Critical Issues Program (@AGI_GeoIssues) shared a map of water resources in Georgia from the Georgia Soil & Water Conservation Commission (@GASoilandWater), which you can find at http://bit.ly/2bZ7px8. If you're interested in states' water resources, make sure to check...
Interactive Map of Oklahoma Water Resources
(2016-09-07)
#MapOfTheDay! Today the Critical Issues Program (@AGI_GeoIssues) shared a map of water resources in Oklahoma from the Oklahoma Water Resources Board (@OKWaterBoard) http://bit.ly/2bIKFDO. If you liked this map make sure to check out the next Critical Issues Forum on the High Plains/Ogallala...
Flyer for the Free Desalination as a Source of Fresh Water Webinar
(2016-09-01)
The American Geosciences Institute Critical Issues Program, along with the National Ground Water Association, the Association of Environmental & Engineering Geologists, and the U.S. Chapter of the International Association of Hydrogeologists will be hosting a free webinar titled, "Desalination...
Drilling rig
(2016-08-25)
August 11, 2016 The Environmental Protection Agency’s (EPA) Science Advisory Board (SAB) released its final report assessing EPA’s recent study of potential impacts of hydraulic fracturing for oil and gas on drinking water resources. Congress requested the study in 2009, and EPA released its draft...
Atlean Lake in British Columbia
(2016-03-10)
February 24, 2016 The House Committee on Natural Resources, Subcommittee on Water, Power, and Oceans held a hearing to discuss the state of California’s water supply. The hearing centered on the main reasons for the decreased water supply in California, with some witnesses pointing to the El Niño-...

Case Studies & Factsheets

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Why water storage? A reliable water supply is essential for economic, environmental, and public health, but natural water supplies vary with the seasons and between years. Water storage, whether in reservoir lakes or underground, helps to ensure that water is available even during droughts....

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The Need for Groundwater Management: Sustaining water supplies and preventing hazards In California, surface water from rainfall, snowmelt, and distant rivers rarely meets the state’s urban and agricultural water needs. Groundwater is an essential water source, providing 35% of the fresh water...

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Introduction Dry wells improve stormwater drainage and aquifer recharge by providing a fast, direct route for rainwater to drain deep into underlying sediment and rock. Dry wells are most common in the western U.S. where clay or caliche layers slow down the natural drainage of water into...

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What is a Dry Well? A dry well is a well that is used to transmit surface water underground and is deeper than its width at the surface (see image, below). Most dry wells are 30 to 70 feet deep and 3 feet wide at the surface. They are lined with perforated casings and can be filled with gravel...

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Fresh water from underground Groundwater is any water found underground in the cracks and pores in soil, sand, or rock. Groundwater provides 25% of the fresh water used in the United States.1 It is particularly important for irrigation and domestic uses in arid or remote areas, where surface...

Research Database Publications

Cover of factsheet; Image credit: IAH
2015, International Association of Hydrogeologists (IAH)
The generation, consumption and management of energy interacts with the groundwater domain in surprisingly varied ways. In consequence specific inputs from hydrogeological science are needed to understand these linkages, and for risk assessment and effective management of the interactions. To...
Cover image of position paper; Image credit: NGWA
2017, National Ground Water Association (NGWA)
The groundwater industry is poised to help move the nation forward in ensuring its long-term water and energy needs are met. Focused, informed federal government policies and funding that support 21st century infrastructure can assist in achieving a secure water and energy future while providing...
Cover of GAMSHPAppRech.pdf; Source: Bureau of Economic Geology
2003, Bureau of Economic Geology (BEG)
This appendix provides a brief overview of previous estimates of groundwater recharge on the Southern High Plains, and presents the results of additional field work and modeling analyses conducted in conjunction with development of the Southern Ogallala GAM model. The field work, conducted in...
Cover of factsheet; Image credit: IAH
2015, International Association of Hydrogeologists (IAH)
Urbanisation is the predominant global phenomenon of our time, and groundwater from springs and wells has been a vital source of urban water-supply since the first settlements. In the modern era, groundwater capture using deep waterwells with submersible electric pumps has enabled major growth for...
Cover of WOFR2015-04; Source: Wisconsin Geological & Natural History Survey
2015, Wisconsin Geological & Natural History Survey (WGNHS)
This report and accompanying figures provide local officials, residents, and the agricultural community with basic information about groundwater and water supply wells in two agricultural regions of Bayfield County, Wisconsin. The work presented in this report was commissioned by the Large-Scale...
Cover of report; Image credit: NGWA
2017, National Ground Water Association (NGWA)
Groundwater is a critical component of the nation’s water resources. Globally, groundwater resources dwarf surface water supplies. Approximately 25 percent of the earth’s total freshwater supply is stored as groundwater, while less than 1% is stored in surface water resources, such as rivers, lakes...
Cover image for WFS 2008-11 ; Source: Iowa Geological Survey
2008, Iowa Geological Survey (IGS)
Will we run out of water? This question is often asked when a proposed ethanol plant or other large water user applies for a water-use permit. The potential for new jobs and economic benefits are often counterbalanced with the concern over the potentially negative impacts this new water user may...
Cover for USGS FS 2014-3096 ; Source: USGS
2014, U.S. Geological Survey (USGS)
Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project (PBP) of the GAMA Program provides a comprehensive assessment of the...
Cover of factsheet; Image credit: IAH
2016, International Association of Hydrogeologists (IAH)
The naturally high microbiological and chemical quality of groundwater, captured at springheads and in shallow galleries and dugwells, has been vital for human survival, wellbeing and development from our earliest history – and remains so today. The purity of groundwater, coupled with its mineral...
Cover image for WFS 2001-13 ; Source: Iowa Geological Survey
2001, Iowa Geological Survey (IGS)
For many Iowans, not much thought is given to the water coming from the kitchen faucet. Where did this water originate? How old is it? Is it safe to drink? For approximately 79 percent of Iowans, the water in their drinking glass is groundwater.