Groundwater

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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...

GOLI Online Courses

GOLI Course: Making Produced Water More Productive; Image credit: USGS/ Doug Duncan
Course Type: GOLI Online Course

Geoscience is essential to our understanding and management of produced water, an inevitable byproduct of oil and gas development. This course provides a scientific and regulatory background of produced water, how it is commonly disposed, what opportunities exist for the re-use of produced water...

GOLI Course: Converting Membrane Interface Probe Sensor Results into VOC NAPL Distribution Information. Image courtesy of Roger Lamb
Course Type: GOLI Online Course

This course will focus on how to use Membrane Interface Probe sensor results in combination with soil and groundwater analytical results to map the distribution of volatile organic chemical non aqueous phase liquids. This course covers guidelines for using direct sensing tools such as the MIHPT...

GOLI Course: Water as One Resource; Image Copyright © Marli Miller, University of Oregon. http://www.earthscienceworld.org/images
Course Type: GOLI Online Course

This course provides an overview of how groundwater and surface water interact, what the implications of these interactions on water resources are, and how water can be more effectively managed if an understanding of these interactions is incorporated.

The course presenters are Ken...

GOLI Course: Desalination as a Source of Fresh Water; Image credit: James Grellier, Licensed under Creative Commons, CC-BY-SA-3.0, http://creativecommons.org/licenses/by-sa/3.0) via Wikimedia Commons.
Course Type: GOLI Online Course

Fresh water is an increasingly scarce resource in an increasingly populous and water-intensive world. Maintaining an adequate supply of fresh water both nationally and globally will be one of the largest challenges of the 21st century. Desalination of salty water – from both the ocean and the...

GOLI Course: Techniques for Developing High Resolution LNAPL Conceptual Site Models; Image courtesy of Roger Lamb
Course Type: GOLI Online Course

This course is intended for geologists involved in Light Non-Aqueous Phase Liquid (LNAPL) assessment and remediation. This course provides information on the development of high resolution conceptual site models that can be used to guarantee the project goals are met. The class will cover...

Research Database Publications

Cover of report; Image credit: NGWA
2017, National Ground Water Association (NGWA)
All successful consulting groundwater professionals engage in business development. It usually means bringing in business, but it can also mean staying billable. In most cases it means a combination of both. Bringing in business requires selling services to prospective clients. Staying billable...
Cover for ES05; Source: Wisconsin Geological & Natural History Survey
2010, Wisconsin Geological & Natural History Survey (WGNHS)
In an average year, the county receives about 35 inches of rain and snow. Of that, about 11 inches reaches the water table. In a very wet year, when as much as 49 inches of precipitation may fall in the county, the estimated average recharge rate is about 15 inches per year. During very dry years,...
Cover for USGS FS 2014-3024 ; Source: USGS
2014, U.S. Geological Survey (USGS)
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...
Cover image for WFS 2008-6 ; Source: Iowa Geological Survey
2008, Iowa Geological Survey (IGS)
Although groundwater by its very nature is hidden and not easily accessible for sampling, there are still plenty of reasons to be concerned about groundwater quality. You may swim or fish in one of Iowa’s surface water bodies during the summer, but there is a high probability that you drink...
Cover image of factsheet Image credit: NGWA
2016, National Ground Water Association (NGWA)
The disposal of carbon dioxide (CO2) into the subsurface via well injection, also known as geologic carbon sequestration or carbon capture and storage (CCS), is one of a portfolio of technologies under consideration as a viable approach to mitigating greenhouse gas buildup. Recognizing that this...
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 of USGS FS2015-3063; Source: USGS
2015, U.S. Geological Survey (USGS)
The Columbia Plateau is a wide basalt plateau between the Cascade Range and the Rocky Mountains that covers parts of Washington, Oregon, and Idaho (fig. 1). The climate over much of the Columbia Plateau is semiarid with precipitation ranging from 7 to 15 in/yr in the central part (Vaccaro and...
Cover of TWDBRechRept.pdf; Source: Bureau of Economic Geology
2003, Bureau of Economic Geology (BEG)
Groundwater recharge is critical in evaluating water resources. Recharge estimates are required for groundwater models being developed as part of the Groundwater Availability Modeling program at the Texas Water Development Board. The purpose of this study was to assess the status of data on...
Cover of OFR96-63 ; Source: Kansas Geological Survey
1996, Kansas Geological Survey (KGS)
Water management policies are established to administer a limited resource. They are all based on the answer to the question: How much water is available in this area (a hydrologic basin or smaller region)? Typically all management policies allow a fraction of the available water to be extracted...
Cover of factsheet; Image credit: IAH
2016, International Association of Hydrogeologists (IAH)
A groundwater-dependent ecosystem (GDE) is a community of micro-organisms, animals and plants, and associated substrates, whose functioning relies on the presence of water under the ground and/or its emergence to the surface. Some GDEs are supported entirely by groundwater while others also receive...