When an aquifer is tapped dry, often it’s lost forever as a source of water
The groundwater in underground aquifers is one of our most indispensable natural resources, but overuse and contamination from human activities are severely endangering aquifer viability, leading to economic troubles, public health ills, and even water conflict. Once an aquifer is depleted, the ground above it tends to subside into the empty space and closes off the aquifer forever. Right now, human activities are draining aquifers far faster than natural systems can replenish them. What will groundwater-reliant populations do when their aquifers can no longer be used?
Reliance on Groundwater
In 2015, approximately 29% of the fresh water used in the United States was sourced from aquifers. A third of the water rural and municipal water departments deliver to households and business is pumped from aquifers, and 90% of the rural population depends on groundwater for its drinking water. Even some major metro areas, like San Antonio, rely exclusively on groundwater. Nationally, agriculture gets 48% of its irrigation water from aquifers. Where surface water bodies are lacking, like in the American West, groundwater’s importance is magnified.
Groundwater makes up as much as 33% of global water withdrawals. More than 2 billion people count on groundwater as their main source of water, and 50% of agricultural irrigation water is pumped from aquifers. It’s a key reserve during prolonged droughts like those in the American West, Brazil, and Australia.
Without groundwater, global water security is far more fragile. But despite its vital importance to humanity, groundwater gets far less attention than rivers and reservoirs, perhaps because it is less visible. But whether we can see it or not, the areas of the world that are most reliant on groundwater are depleting it far faster than it can be replenished by natural processes.
Critical aquifers, most of which irrigate the most productive agricultural regions in the world, include those in:
The North China Plain
Australia’s Canning Basin
The Northwest Sahara Aquifer System
The Guarani Aquifer in South America
The High Plains and Central Valley aquifers of the United States
Northwestern India and Pakistan
The Middle East
Threats to Groundwater
Population growth is one of the major threats to aquifers. More humans mean more human activities, whether household, agricultural, or industrial. Industrialization and rising living standards are contributing to water demand.
In Texas, where state officials recently proclaimed they were “about three Lake Meads” short of water, human activities and evaporation do not always explain the aquifer depletion, and the solution to the mystery remains elusive.
Large areas of the Jakarta, Indonesia, are quickly sinking into the Java Sea. One might expect to hear the problem is climate change-associated sea level rise, but aquifer depletion is the greater problem. When aquifers are emptied under the city, the land under the city begins to subside.
And that goes for rural agricultural land on the other side of the world in California. San Joaquin Valley growers have depleted their aquifer so severely that in some places, the ground has subsided more than 20 feet, and the loss of the aquifer’s water storage capacity is considered to be largely permanent.
Depletion in coastal areas worldwide also leads to saline intrusion into aquifers as seawater seeps in to fill the void, rendering aquifers brackish and unusable for most purposes without treatment. In central and Southern California, water management is injecting freshwater into aquifers to halt saline intrusion.
Natural systems cannot recharge heavily used aquifers faster than growing populations deplete them, but we can help replenish them. The use of pervious concrete pavement, for instance, allows water that might have been disposed of in gutters to percolate into aquifers. Managed aquifer recharge (MAR) identifies sites that are ideal for water to enter aquifers and diverts the water to them.
California growers, in partnership with local authorities, are diverting excess river flows during wet years into “water parking lots,” which allow the water to percolate into the aquifer for use in dry years.
Wastewater Reuse
Where there is no water to divert, even raw sewage can be converted into high-quality effluent that can replenish groundwater.
In California, cutting-edge water reuse technology, such as Fluence’s membrane aerated biofilm reactor (MABR), has been certified at Stanford University to conform to strict California Title 22 standards. Due to its simultaneous nitrification-denitrification, MABR has very high nutrient removal and produces effluent suitable for managed aquifer recharge and agricultural reuse.
Fluence provides MABR in two lines of products, Smart Packaged Aspiral™, which is suitable for decentralized treatment, and SUBRE, which allows existing wastewater treatment plants to be retrofitted with MABR modules.
Brackish Water Aquifers
Where saltwater has already contaminated aquifers, brackish-water desalination is an option that is becoming ever more viable. In fact, brackish water is easier and less expensive to desalinate than seawater. With technological advances dropping the high price of desalination, the desalination of brackish groundwater is becoming more and more viable.
Also, in a discovery with global implications, a brackish aquifer under 15,000 square miles of seabed was recently found in the Atlantic off the coast of the U.S. Northeast. Although the area has not yet suffered water shortages that justify tapping brackish aquifer, scientists say the discovery infers such undersea aquifers may be common worldwide, offering a virtually limitless supply of water that is much more readily desalinated than seawater.
A range of Fluence products can help communities safely convert their wastewater into a high-quality effluent to restore their aquifers or allow them to sustain themselves on brackish water reserves. On Cyprus, for instance, a Fluence desalination plant uses brackish water reverse osmosis and has a capacity 10 million L/d of top-quality drinking water. In China, Fluence is commissioning 80 Aspiral MABR wastewater treatment plants that will allow Hubei Province highway service areas to safely replenish the local environment with high-quality effluent.
Contact Fluence for the technology and expertise to turn brackish water into high-quality drinking water and safely replenish aquifers.
Groundwater being pumped from the Great Artesian Basin, Australia, to produce hydro-electric power.
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It may be out of sight, but it should not be out of mind.
Water hidden beneath the earth’s surface comprises 98% of the planet’s fresh water. On average, this groundwater provides a third of all total water consumed, and its preciousness is ever more palpable since Cape Town’s water crisis sent shock waves rippling around the world.
Despite this, its regulation is far from ideal – especially now that drought conditions are intensifying around the globe and people are increasingly drilling downwards.
Before we even start to improve groundwater management, we must better understand and measure it, says international groundwater expert Craig Simmons, from Flinders University in Adelaide, Australia.
“A lot of the problems that we have in groundwater are because we don’t have even the basic understanding on some of these systems,” he says.
Many subterranean aquifers have been around for centuries or even hundreds of millennia, nurturing trees and vegetation, permeating spaces and crevices in dirt, sand and rock and networking with rivers, streams, lakes and everglades.
Farmers use bores to draw water up from artesian basins and windmills generate energy to pump it from underground aquifers. Groundwater is used to wet vast swathes of agricultural land. Many cities source it for irrigation and industrial processes that might be less obvious, like beer and soft drink production. Other activities that draw on groundwater include mining and coal seam gas extraction.
Above all, it is an important source of drinking water, supplying half the world’s needs overall. In the U.S., half of city populations and virtually all rural people rely on it. Some Australian cities depend increasingly on it as surface water sources dwindle.
But groundwater is not an infinite resource; it’s like drawing money from the bank without replenishing it, Simmons says.
Over-exploitation can lead to a litany of problems.
Extracting groundwater causes drawdown. This can impact delicate ecosystems and biodiversity. For instance, groundwater feeds vegetation and replenishes intermittent streams that communities of fish and aquatic invertebrates depend on. Wet streambeds are also important sites of microorganism activity, carbon and nutrient recycling.
Some areas may house species that live there exclusively. In the Great Artesian Basin, Australia’s biggest groundwater basin, for instance, 98 endemic species of flora and fauna have been identified, and these are at risk from drawdown.
Subsidence is another problem that occurs when the ground level sinks from over-pumping and resulting depressurization.
“The land just compacts because there’s reduced pressure,” Simmons explains. “It’s like taking air out of a tire; it just starts to collapse under the weight of the rock and soil.” The most extreme example of this is in San Joaquin Valley, California, where the ground level has sunk by more than eight meters since the 1920s – that’s nearly the height of a telegraph pole.
Seawater intrusion is another issue. It occurs naturally along the coastline but can be aggravated by extracting groundwater from nearby aquifers. This is a major problem in regions like Australia with high coastal populations. If the seawater seeps inland it can contaminate bores with salty water, wasting money and taking centuries to remedy. Excess pumping can also draw salt in by drilling deeper into the earth.
“So water quantity and water quality are often connected issues,” says Simmons.
Groundwater can be contaminated by other pollutants such as gasoline, oil, chemicals, pesticides and fertilizers. Toxic substances from mining sites, landfill, hazardous waste sites and untreated septic tanks can also make their way into it.
Simmons’ research focus is complex groundwater modeling, which he says is a fundamental tool. “It’s like being able to predict the weather tomorrow,” he explains.
Current groundwater modeling has a huge error margin. “It’s kind of like saying the weather tomorrow will be anything between 12 degrees and 43,” he laughs. “That’s kind of not very helpful.”
One aspect of groundwater his team is trying to understand is aquifer recharge rates, which Simmons says is a vital area of management; finding better ways to estimate “how much money’s topping up your bank account, not just how much you’re spending”.
They have also worked on improved comprehension of groundwater’s connection to surface water. This is critical because water allowances could double up if they are managed separately – extracted groundwater might be pulling from a nearby river, for instance.
One of Simmons’ latest projects will model the impact of faults and barriers on the flow of groundwater and solutes at mine sites.
“By combining geological, hydraulic and geochemical approaches with 3D numerical models, we will gain an improved understanding of the role of faults and barriers in subsurface hydrology, and an improved ability to model complex groundwater systems,” he explains.
Ultimately, the world’s water problems will need a combination of solutions to better understand and manage water and tighten up on water use and efficiency, factoring in all water sources.
“It’s about how do you get the right mix of water supplies for drinking water, whether it’s surface water, dams, rivers, reservoirs, groundwater,” Simmons says. “That optimal mix is a critical issue that we often don’t understand – and desal is a part of that too.”
As well as modeling the supply side, it’s important to understand the impact of human activities, such as mining, agriculture, coal seam and shale gas extraction, on groundwater and ecosystems. Simmons’ team is developing software models to predict those processes and impacts as well, to better inform environmental impact statements.
In that sense, accurate modelling will be like a guide dog for the blind, and hopefully give more credibility to widespread concerns about large industries sourcing groundwater haphazardly.
“It’s about looking at the use of water and what the impacts of that use are environmentally,” says Simmons. “And it’s always going to be a social, economic and environmental triple bottom line.”
Movies have long helped us understand what it means to live on earth and contribute to an ecologically sustainable planet. Here are ten of our favorites.
In one vision of the distant future, after global warming has melted the ice caps and left the planet covered in water, Kevin Costner grows fish gills, lives on a trimaran, and battles pirates as he sails in search of the legend of “Dryland.”
Waterworld is a constant reminder of the risks associated with making environmental movies. In 1994, it was the most expensive film ever, and the heart of the story was a future ravaged by global warming. It didn’t help that the film was terrible, but Waterworld continues to color the way we think about environmental movies.
Waterworld highlights a problem for environmental cinema: Discussions tend to focus on a fairly narrow range of films, often defined primarily by celebrity documentaries (An Inconvenient Truth, The11th Hour), the occasional message movie (Promised Land), disaster/post-apocalyptic movies (The Day After Tomorrow), and Wall-E. For most viewers, the world of environmental movies is small.
But filmmakers have long considered the environmental consequences of human behavior, imagined ecological changes on local and global scales, explored catastrophic failures of resource management, and told all kinds of other planetary and environmental stories. Sometimes, these themes are central to a film’s story. In the best ones, such elements underlie a well-written narrative that tells a gripping story about personal relationships, challenges the way we think, or expands our views of the human experience.
This list is meant to expand the way we think of movies that address our planet’s health and the ways in which our own well-being is connected to it. Some are obvious choices and others may be surprising, but each contributes to our understanding of what it means to live on earth and contribute to an ecologically sustainable planet.
Here’s our take on the ten films most likely to inspire your inner environmentalist.
10. Prophecy (1979)
Nowhere in cinema are the consequences of humanity’s manipulation of nature more directly embraced than in horror movies. The freakish results of scientists’ meddling into the natural order has been plaguing large cities, small towns, and rustic cabins since the genre came to be. Manipulating the dead led to Frankenstein’s monster continuously terrorizing locals on-screen since 1931. The fallout of our nuclear weapons awakened the Tokyo-destroying Godzilla of 1954.
But it wasn’t until the creature features of the 1970s and 80s that the horror genre began a deep dive more directly into environmental territory.
Killer monsters roaming the lands are not particularly insightful centerpieces for cinematic ingenuity, and John Frankenheimer’s fairy-tale-gone-wrong about industrial pollution, Prophecy, isn’t a great movie. But it’s a fantastic example of the B-movie camp that made the era’s horror so memorable.
The story opens with the disappearance of two lumberjacks. An EPA employee heads out to study the impacts of local logging efforts accompanied by rescuers searching for the missing loggers. It’s only a matter of time before something—possibly the vengeful spirit Katahdin of local native mythology?—appears in response to the logging activity and brings with it carnage and death. The beast itself, a giant, bear-like mutation created by industrial toxic pollution, terrorizes the woods and its inhabitants with no shortage of body count and blood. In the middle of all the puppetry and outrage and gore-filled ridiculousness is an actual story about the dangers of human carelessness and arrogance.
9. Avatar (2009)
There is much in James Cameron’s epic sci-fi morality play Avatar to dislike. From its unoriginal premise (see: Dances with Wolves) to its embrace of violence as the preferred mechanism for problem-solving, to its final, heavy-handed Cameron-esque lesson, complete with speeches and battles and glorious sacrificial deaths.
Nevertheless, none of that erases the fact that Avatar is a beautifully imagined ode to our deepest connections with the natural world. James Cameron spent $237 million and almost a decade making an incomparable blockbuster plea for environmental protection and respect for indigenous lands. That’s a truly remarkable effort. It is the most expensive environmental advocacy effort in human history—and wildly successful.
That Avatar earned almost $3 billion worldwide—making it the most successful film in history—only reinforces the importance of the film. Fifty years from now, Avatar may be remembered as having played an important cultural role in the era of climate change politics; or perhaps it’ll be seen as a bloated, sentimental blockbuster.
Either way, the highest-grossing movie of all time also happens to be an environmental call to arms by a director who has compared climate change to “the threat the United States faced in World War II.”
8. FernGully: The Last Rainforest (1992)
Would there be an Avatar without its little animated predecessor, FernGully: The Last Rainforest?
Animation is a genre that has deep ecological roots. Animated films from East and West have long explored the interconnectedness between humanity and the planet. And when it comes to Western animation, FernGully: The Last Rainforest is among the most treasured environmental films.
Set in an animated rendition of Australia’s rainforests, the film pits loggers—again (always any easy villain the pictures)—against a magical, unseen world that lives deep within the woods.
What FernGully lacks in depth and inspiration—it’s a fairly straightforward kids’ production—it makes up in dedication to its cause. Released in 1992, FernGully may feel a little dated (1990s Robin Williams, who voices Batty, dates everything). But kids today still respond to the magical world of Crysta and her fairy friends, and their life-depending need to keep the rainforest intact, free from exploitation.
7. I Heart Huckabees (2004)
About as strange a movie as one can imagine (Roger Ebert’s description is perfect: “The movie is like an infernal machine that consumes all of the energy it generates, saving the last watt of power to turn itself off”), I Heart Huckabees is not a movie for everyone (perhaps it is in fact a movie for no one).
The film centers on two existential detectives and their work with a coincidence-obsessed leader of the local Open Spaces Coalition and a young corporate employee whose life is falling apart. There’s also an anti-oil fireman who only rides a bicycle, a French philosopher creeping around the edges of the story, an African refugee autograph collector, and the human search for universal connectivity.
But despite all the manic craziness, the film and its characters take climate change and environmental protection seriously. In fact, I Heart Huckabees is one of the rare non-documentary films of the past decade that portrays an actual debate between smart and serious adults over the values of conservation, the impacts of consumerism, global poverty, and geopolitics.
What will it actually mean to reduce our oil consumption? Do the negative effects of globalization outweigh the benefits of industry, jobs, or medicine? How is American behavior responsible for the conflict in the Sudan? These real and difficult questions are all raised around a dinner table in a single scene. That the scene occurs in the middle of a comedy about identity crises and a campaign to protect a rock from a parking lot makes its presence even more memorable.
6. Erin Brockovich (2000)
The real-life story of Erin Brockovich and her fight against the contamination of groundwater by California’s Pacific Gas and Electric has become as famous as Julia Roberts’ décolletage in Steven Soderbergh’s rendition of the tale.
Erin Brockovich is the story of a single mother of three working in a legal office, who encounters the medical records of a local woman who was treated by PG&E doctors. Looking more closely, Brockovich finds many community members with similar illnesses, all treated by the same doctors. Eventually, she reveals a decades-long corporate cover-up of pollution and ensuing health problems.
Soderbergh’s biopic about an unintentional activist is among the best films about environmental activism—a niche that also includes Silkwood, A Civil Action, and Michael Clayton.
5. Bambi (1942)
It’s been 70 years since Bambi first traumatized children with the most famous hunting expedition in movie history. And yet the tale of Bambi and his friends continues to inspire a love of wildlife in its viewers. Touching and sad and scary, the relationships between Bambi, his protective mother, and his friends are as deep and loving as one will find anywhere else on screen.
There is no question that Bambi has altered the landscape of wildlife protection. And like anything that has lasting cultural impact, the results haven’t been entirely positive. The Bambi Effect—a special interest among the public in the protection of animals we find particularly adorable, like cute little deer, at the expense of those animals considered ugly or pests—has created difficulties for wildlife management efforts. Just look at the complicated issues of deer in urban environments, chronic wasting disease, and culling efforts to see the Bambi Effect in action.
4. The Road (2009)
Dystopic visions of the future pair well with environmental themes. John Hillcoat’s adaptation of Cormac McCarthy’s novel The Road exemplifies the dark, cold, and unfriendly future of life after nature.
The Road tells the story of a man and his son as they scavenge for survival in the wake of an unnamed catastrophic event that has destroyed the natural environment and most of humanity. Of those who survived, some search the remains of the planetary wasteland looking for cans of food and sodas. Others have grouped together into roaming bands of cannibals. It’s a merciless vision of a time best avoided.
What separates The Road from the recent wave of post-apocalyptic cinema is the quiet, foreboding determination of the film and its characters. Even after catastrophic biological devastation, life moves slowly, allowing viewers plenty of time to inhabit a world we start to see as one we need to protect if we are to save ourselves from each other. That may sound preachy, but The Road is not a lesson tidily packaged for its audience. It’s a simple story of love and sacrifice in a setting beyond horror.
3. Soylent Green (1973)
“The people will do anything to get what they need,” says the trailer for one of the most famous resource depletion films in modern movies, the 1973 Charlton Heston sci-fi film, Soylent Green. Set in an overpopulated, urban Earth in 2022, the world survives on food rations produced by the Soylent Corporation, which has just released a new product: Soylent Green. When the director of the Soylent Corporation is murdered, a detective (Heston) finds himself in the midst of a massive cover-up, and the target of assassination to protect the secret of Soylent Green.
The cultural reach of Soylent Green today far outpaces the film itself (if you haven’t seen the film, you’ve probably seen it paralleled in “Buffy the Vampire Slayer,” or parodied on “The Simpsons”). But Soylent Green remains a darkly satisfying cinematic experience—a smooth interplay of police procedure, sci-fi, and horror—and one that understood early the severity of a food crisis that just might be in store for in our future.
And for film aficionados, Soylent Green is the final film in the illustrious career of the actor Edward G. Robinson, who died of cancer only 12 days after filming wrapped. With this knowledge, his is a wonderful and sad performance.
2. Princess Mononoke (1997)
For 30 years, master storyteller and animator Hayao Miyazaki has been creating meticulously rendered animated worlds and telling bold, moving stories. His final film, The Wind Rises, is coming to American theaters next February.
The best film in his amazing body of work is Princess Mononoke, a dark tale of combat between nature and technology. In Mononoke, the march of the Iron Age threatens the peace and harmony of the world as it has existed forever. Ashitaka—a young man cursed by a demon he killed while protecting his town—goes in search of a cure. He finds a battle being waged between the inhabitants of Iron Town and the creatures of the spirit world tasked with protecting the forests. Ashitaka is human and part of the progress of time, but finds his loyalties torn between nature and humanity.
It’s a time of conflict, where tree-spirits and wolf gods are threatened by steel blades and guns. As the conflict nears completion,Miyazaki’s portrayal of the great Forest Spirit’s transformation from beauty to monstrosity demonstrates the unparalleled artistry of anime like few other moments I’ve found.
The defense of the natural world has rarely been as moving, visually engrossing, and morally complicated as it is in Princess Mononoke. It is a masterful feat of imagination that reminds viewers what movies are capable of providing: a wholly original experience in a world unlike any we’ve seen.
1. Chinatown (1974)
The 1970s was a benchmark decade for environmental policy. Never before or since has as much action been taken on the federal level to address the issues of pollution and toxics, resource management, water and air protection, and a host of other problems. Environmental issues were in the mainstream, and it just happens that American cinema was surging.
Thus the 1970s brought many films about environmental and ecological subject matter—including three on this list, and our number one: Chinatown. Written by Robert Towne and directed by Roman Polanski, Chinatown tells the story of Jake Gittes, an private detective hired to investigate an affair who unwittingly discovers a major conspiracy.
A detective noir story at heart, Chinatown follows Gittes as he discovers a nefarious plan to manipulate the water supply. Someone is destroying water tanks in San Fernando Valley and pumping more water into Los Angeles than needed, all in an effort to drum up support for the construction of a new reservoir. It’s a complicated and corrupt plan that leaves Gittes entangled in dirty California politics—and an even dirtier family drama.
Considered among the best American films ever made, Chinatown takes seriously not only the story at its core, but builds immense personal and political drama around the simple, universal dependence we all have on one of the basic building blocks of the natural world.
This paper summarizes the results of efforts to bring attention to the importance of understanding and improving groundwater governance and management. Discussion of survey work in the United States and global case studies highlights the importance of focusing attention on this invisible water resource before pollution or depletion of it causes severe economic, environmental, and social dislocations. Better governance and management of groundwater are required to move toward sustainable groundwater use.
Introduction
The growing population’s increasing demand for water for food, energy, and other human uses and changing climate’s impacts to both water supplies and demands are resulting in increasing reliance on groundwater. In many places groundwater is being depleted faster than nature replenishes it, and its quality is being compromised. Groundwater “mining” can have negative implications for meeting long-term water needs of people and natural systems. At the same time that groundwater from deeper and saltier aquifers is eyed for meeting future drinking water needs, aquifers are being identified as repositories for waste streams from desalination and energy processes as well as carbon sequestration sites. As dependence on groundwater increases, water managers and policy makers must pay careful attention to both groundwater quality and quantity. This paper focuses on efforts to bring attention to the importance of understanding and improving the governance and management of this invisible and increasingly relied-upon resource. It is essential that water users focus attention on this invisible water resource before pollution or depletion of it causes severe economic, environmental, and social dislocations. Better governance and management of groundwater are required to move toward sustainable groundwater use.
Multi-disciplinary and collaborative efforts to bring attention groundwater management and governance
In 2011, global leaders in groundwater monitoring and management embarked on an effort to highlight best practices in groundwater governance. Completed in 2016, the Groundwater Governance Project “aimed to influence political decisions thanks to better awareness of the paramount importance of groundwater resources and their sustainable management in averting the impending water crisis”.1 The three final project documents and extensive background documents2 provide a rich overview of the issues associated with managing groundwater at different geographic scales. The stated need for this project on groundwater governance was predicated on the rapid increase in groundwater extraction and its invisibility. Unlike surface water, which can be seen and touched separately from its consumption, water consumers generally have little understanding of groundwater quantity and quality.
I will note here that there are about as many definitions of (ground)water governance as there are papers or books written on it. I like to use the following single-sentence definition, which I developed with coauthors: Groundwater governance is the overarching framework of groundwater use laws, regulations, and customs, as well as the processes of engaging the public sector, the private sector, and civil society.3 This framework shapes “what” is done, that is, how groundwater resources are managed and how aquifers are used.
I had the good fortune of being invited to participate in the regional consultation portion of the project, where water management professionals from around the world were invited to participate in one of five regional consultations. The consultations were held in Uruguay, Kenya, Jordan, China, and the Netherlands. It was for the final regional consultation held at The Hague in March 2013, where United States (US) practices would be shared, that I was motivated to characterize the US’ decentralized approach to groundwater governance. I will report more on the efforts to describe US groundwater governance and management in the next section.
In 2016, two independent efforts, one in the United States and the other more globally based, attempted to bring greater attention to the importance of wise governance and management of this invisible resource through dialogues from which principles or directives emerged. The American Water Resources Association (AWRA) and the National Groundwater Association, two US-based national organizations dedicated to knowledge sharing, education, and good water stewardship, joined forces and convened the April 2016 Groundwater Visibility Initiative workshop. I was on the workshop organizing committee and contributed to the efforts to disseminate workshop findings. The six summary principles are as follows:4,5 (1) Governing and managing groundwater require working with people; (2) Data and information are key; (3) Some “secrets” remain; (4) We need to take care of what we have; (5) Effective groundwater management is critical to an integrated water management portfolio that is adaptive and resilient to drought and climate change; and (6) To be robust, policies of the agriculture, energy, environment, land-use planning, and urban development sectors must incorporate groundwater considerations. Perhaps most wide-ranging of the findings-conclusions is the recognition that effective groundwater management is critical to an integrated water management portfolio that is adaptive and resilient to drought and climate change. In addition, the importance of groundwater considerations to policies related to agriculture, energy, environment, land-use planning, and urban development was underscored. Fundamentally, the workshop concluded that it comes down to the relationship of the water consumers to the resource. Are they organized to manage the resource and, if so, on the basis of what information? A major thrust of this effort, like the global Groundwater Governance Project, was to bring attention to the important, growing, and often misunderstood status of groundwater in meeting human and environmental water needs.
The second effort emerged from the Ninth International Symposium on Managed Aquifer Recharge (ISMAR9), which was held in Mexico City in June 2016. A subset of groundwater experts from across the globe convened to draft a set of principles for sustainable groundwater management.6 The six principles or directives from this effort include stopping depletion of aquifers, acquiring and sharing information on aquifer systems, and managing groundwater within an integrated water resource framework. Specifically, the directives are (1) Recognize aquifers and groundwater as critically important, finite, valuable, and vulnerable resources; (2) Halt the chronic depletion of groundwater in aquifers on a global basis; (3) Aquifer systems are unique and need to be well understood, and groundwater should be invisible no more; (4) Groundwater must be sustainably managed and protected within an integrated water resource framework; (5) Managed Aquifer Recharge should be greatly increased globally; and (6) Effective groundwater management requires collaboration, robust stakeholder participation, and community engagement. It is not surprising that a group convened to explore managed aquifer recharge urged increased implementation of MAR efforts. Again, the importance of stakeholders was noted: Effective groundwater management requires collaboration, robust stakeholder participation, and community engagement.
While the Water Governance Initiative led by Paris-based Organisation for Economic Co-operation and Development (OECD) is not exclusively focused on groundwater, this initiative has also emphasized the role of stakeholder engagement.7,8 However, what is less recognized is that sustaining meaningful stakeholder participation is resource intensive. I still see very limited resources going into stakeholder engagement efforts.9 This is true at a time when professionals from multiple backgrounds are concluding that the barriers to agreeing upon a strategy to address many of the world’s thorniest water challenges are those related to the human dimensions of water sector decision-making rather than engineering or even financial constraints.
Most recently, in early 2018, the AWRA adopted its “Policy Statement on Fresh Groundwater”.10 The AWRA recommends that groundwater be managed according to the tenets of Integrated Water Resources Management and that attention focus on the following ten action items so as to advance sustainable groundwater management, presented here in abbreviated form: (1) Assessing the resource; (2) Building partnerships; (3) Aligning the legal framework; (4) Including groundwater considerations; (5) Maintaining sustainability; (6) Respecting ecosystems; (7) Engaging stakeholders; (8); Committing to understand; (9) Protecting the asset; and (10) Utilizing interdisciplinary approaches.
I am therefore encouraged that hydrologists, engineers, and other physical scientists are increasingly acknowledging the importance of collaboration across disciplines and the need for robust stakeholder participation.
Efforts to characterize and share US groundwater governance practices
What do we know about actual governance practices that lead to good groundwater stewardship? The Groundwater Governance Project had sharing governance practices at its foundation. It convened water managers and decision-makers from jurisdictions large and small, ranging from island states to large countries. This was necessary because groundwater is primarily a local resource. Approaches to its governance and management will reflect relevant laws and regulations, along with local physical and economic conditions. No cookbook approach to groundwater governance has emerged. What has turned out to be illuminating and helpful is the comparing of experiences so that decision-makers, water professionals and other can learn from each other’s successes as well as challenges.
As I participated in the more global dialogues, I observed something that bothered me. Often, conditions for the US were shown on a map in a single color, meaning that conditions were uniform across the US. Nothing can be further from the truth in a country as large as the US. While some may inherently acknowledge this, my guess was that few engaged in global discussions on groundwater governance and management recognized just how decentralized groundwater authorities and agencies are across the US. Despite the US being a nation of states, aside from national regulations addressing the quality of drinking water and discharges of water into navigable waters, there is little other federal guidance on groundwater quantity or quality. To help document the diversity of governance and management approaches across the US, a small team at the University of Arizona undertook an effort to characterize elements of this diversity. Armed with a survey of the literature that revealed no recent survey of state practices, we undertook an initial and survey of the states to demonstrate that one cannot paint the US groundwater governance and management picture with a single brushstroke.11 This survey targeted experts from state agencies responsible for water quantity regulations. One of the survey results was that most states had different government agencies managing water quantity and water quality.
Figure 1 shows quite a bit of variation in reliance on groundwater across the US states. Indeed, within states there will be additional variation. Super-imposed on the coloring showing the level of extent of reliance on groundwater are hatch marks showing states that reported a focus on declining groundwater levels. Several states with limited reliance on groundwater for overall state water demands indicated concern with declining groundwater levels.
Fig. 1
States’ reliance (as a %) on groundwater for total water withdrawals and states concerned with declining groundwater levels. (reproduced with permission from ref. 3, Copyright National Ground Water Association 2015)
As Fig. 2 shows, water quality or contamination was the most frequently cited priority—even by personnel from state-level water quantity agencies. Because water quality determines the cost of using groundwater for different purposes, water quality and quantity are intrinsically connected.
Fig. 2
Groundwater governance priorities. (reproduced with permission from ref. 3, Copyright National Ground Water Association 2015). The items listed, in order of frequency, were selected by respondents as their state groundwater governance priorities
This finding was validated by a more recent national survey that focused on groundwater quality.12 For our “State-level Groundwater Governance and Management in the U.S.—Summary of Survey Results of Groundwater Quality Strategies and Practice”, we surveyed state water professionals primarily from water quality agencies. As summarized in Fig. 3, respondents identified several groundwater concerns, including impairment of water quality and quantity, staffing and budget issues, health/vulnerability of private well users, and aquifer overdraft, with water quality being the most frequently cited. Contamination of groundwater, especially in agricultural sites but also due to naturally occurring contaminants, was a key concern. Additionally, underground storage tanks, Superfund/CERCLA sites, industrial sites, and septic tanks were noted by many survey respondents. Nitrate and chlorinated solvents were the two most cited contaminants.
Fig. 3
Frequency of groundwater concerns listed in the top three by states (Number responding = 48) (based on data from ref. 12)
Most respondents pointed to the existence of groundwater quality management goals and noted that significant changes to groundwater quality policy occurred in the past decade. Extensive information sharing of groundwater quality data was reported, with most states having groundwater quality standards and a groundwater classification system. States reported multiple sources of funding for water quality programs, with 85% depending at least in part on federal funding. However, states reported challenges associated with decreasing groundwater quality program budgets. Looking to the future, water quality/water level monitoring and increased groundwater pumping were identified as requiring additional attention.
Because both surveys targeted only one respondent per state, should resources be available, additional inquiry and analysis would help validate the results. Nevertheless, the results can indeed be used to portray the richness and diversity of groundwater governance and management issues faced across the US and aid those interested in understanding how experiences elsewhere relate to their own priorities, challenges, and policies.
Considerations of transboundary aquifers and groundwater governance case studies
Groundwater governance and management practices will reflect the geographic reach of aquifers, jurisdictional boundaries, and the rules and regulations set forth by the relevant nation, state, or locality. Special attention must be given to aquifers that cross boundaries (see ref. 13 for a summary of interesting cases and the myriad issues that arise). The almost 600 known transboundary aquifers are mapped by the International Groundwater Resources Assessment Centre.14 The governance of transboundary aquifers must respect the sovereignty of nations, including tribal nations, and their different regulatory frameworks, cultures, and often languages. For over a decade, I have been involved in assessment of aquifers along the US-Mexico border. Collaborative assessment of transboundary aquifers is likely the precursor to transboundary governance and management because it is difficult to manage aquifers that have not been characterized through an agreed-upon methodology. The experiences of the Transboundary Aquifer Assessment Program (TAAP) along the US-Mexico border demonstrate the importance of establishing the rules of engagement for binational investigations. The cooperative framework developed for it can serve as a model for others undertaking similar efforts, whether across or within nations.15
Case study analysis is useful to identifying good practices and determining trends.16,17 While a survey or review of groundwater governance case studies is beyond the scope of this perspective article, a look at the case study section of the released volume, Advances in Groundwater Governance,18 is instructive. In addition to a chapter by this author and others focusing on the US,19 the section includes seven case studies from across the globe.
Habermehl explains how national legislation in Australia, the Environmental Protection and Biodiversity Act of 1999, which explicitly requires protection of groundwater-dependent ecosystems, applies to the Great Artesian Basin.20 Dinesh Kumar addresses how the sub-regions of the Indo-Gangetic Plains of India21, the “cereal bowl” of India, face distinct groundwater problems and management challenges due to their different physical, economic, and social characteristics. Two recommendations offered to help the sub-regions move to groundwater sustainability are pro rata pricing of electricity and a water rights system, both in conjunction with each other. Fried et al.22 consider the evolution of groundwater governance in the European Union and explain how science-policy dialogue over time has extended groundwater governance concerns to include environmental considerations and incorporate the connection between groundwater and surface water. The move from private ownership to public ownership of groundwater was a significant feature of the 1998 South African National Water Act.23
The chapter on the Middle East-North Africa region expresses pessimism regarding moving to sustainable groundwater governance and management due to ineffective state-level governance and limited participation of water users in improving the frameworks.24 The authors see continued depletion of groundwater systems, with the concomitant implications for water quality and cost of extraction. Amore25 emphasizes the multiple levels of actors in his discussion of the transboundary Guarani aquifer, which is shared by Argentina, Brazil, Paraguay, and Uruguay. On the first page of his chapter, Amore emphasizes the complex inter-jurisdictional relationships when he writes about the Guarani Aquifer Project: “…the weakest and most crucial level to foster groundwater governance is the local or municipal level, because it is at this level that all contamination and overexploitation problems of the aquifer really occur. Many expectations are supposed to be resolved after the Guarani Aquifer Agreement’s enforcement; one of them is how regional and national level can effectively support the local level, a critical dimension to mitigate impacts and develop protection strategies to the Guarani Aquifer.” Finally, the chapter by Hirata and Escolero compares and contrasts the groundwater situation for the two largest metropolitan areas in Latin America – São Paulo, Brazil and Mexico City, Mexico.26 Mexico’s water supply is owned by the federal government, which has a water rights and permitting system and which allows for marketing of water rights. However, there, as in São Paolo, the governance framework is complex and fragmented, with the authors pointing to lack of enforcement capacity and ineffectiveness.
Returning to the US, although US groundwater regulation is determined by the states, some states further delegate authorities or responsibilities to regional districts or other sub-state jurisdictions, the Megdal et al. chapter in the Villholth volume highlights the experiences of two states—an early adopter and a late adopter of state-level groundwater governance frameworks. In 1980, Arizona, my home state, led the way in adopting comprehensive groundwater regulations for areas called Active Management Areas. California, with 38 million people, did not enact a statewide framework for groundwater regulation until 2014. With California being home to one of the largest economies in the world, attention is focused on the implementation of California’s 2014 Sustainable Groundwater Management Act.27,28 However, it is too early to report on the effectiveness of this recent legislation.
Neither Villholth et al. nor I can offer a recipe for those striving to achieve sustainable groundwater management. Returning to its local nature, strategies will depend on the local situation, including those related to community norms and values. Villholth et al. provide early acknowledgement of this when, in their Preface to ref. 18, they state: “The book does not present final conclusions or recommendations as no silver bullets exist for groundwater governance.”
Concluding remarks
Groundwater, the invisible water supply, is becoming more visible in dialogues on the challenges of meeting the world’s food, energy and water needs. The governance and management of this resource will often be at the scale of the source aquifers. Many across the globe are working hard to bring greater attention to the importance of good governance and management of this oftentimes non-renewable resource. As the state-level survey work demonstrates, quality considerations are paramount to those responsible for regulating groundwater. Along with other factors, quality considerations will determine groundwater’s usability. The case studies discussed underscore that groundwater is largely a local resource, with its governance and management vital to the livability and productivity of regions around the globe. Water policymakers, users, researchers, and citizens must focus attention on this invisible water resource before pollution or depletion of it results in severe economic, environmental, and social dislocations.
The desert cities in Central Arizona have withstood 22 years of ongoing drought without imposing emergency conservation measures, such as those California ordered in 2015. Much of the credit goes to a groundbreaking piece of legislation called the Arizona Groundwater Management Act. The 37-year-old law is responsible for Arizona’s reputation as a leader in water management. The true story of how this law was negotiated, written and passed is the subject of a 2015 documentary called Groundwater: To enact a law for the common good. Unlike many documentaries about water, this one is often humorous as former power brokers explain the rancor and slippery tactics that lead to the story’s happy ending.
A Little Background: Groundwater is found in aquifers beneath our feet, where it has accumulated over millions of years. Very little groundwater is naturally replenished in Arizona and the southwest, and as groundwater is depleted, wells must be drilled deeper and deeper to reach water. Ultimately, the aquifer will go dry. Before 1980, Arizona’s growing cities and expanding agricultural and mining industries were pumping groundwater at an alarming rate, and it became obvious that the state could not build an economy on the unregulated use of a finite water supply.
The 1980 Groundwater Management Act addressed this problem in central Arizona by prohibiting the expansion of farmland, requiring an assured 100-year water supply for new residential development, limiting the drilling of new wells, and imposing mandatory conservation requirements. With these measures in place, groundwater depletion in central Arizona has been slowed dramatically.
Political Showmanship: The Groundwater Management Act was the culmination of nearly three years of negotiations that required the political and economic giants of the time – mining, agriculture and growing municipalities – to agree to a plan that regulated their water use. The idea of these special interests reaching an agreement then was about as likely as it would be today. Defying the odds, they found a way. The proposed agreement went to the Legislature with another gamble: pass it as written without amendments or don’t pass it at all. The Act passed.
Groundwater: To enact a law for the common good tracks this political drama and has become a cult classic in the water world since its October 2015 premiere at the Phoenix Art Museum. Arizona PBS aired the 30-minute documentary in 2016 and it just became available on Amazon, iTunes, YouTube and Google Play.
Making the Movie: The film was produced by a partnership of knowledge and art. Attorney and former AMWUA Executive Director Kathleen Ferris contributed her expertise earned through decades of shaping Arizona water law, including her 1977 appointment as Executive Director of the Groundwater Management Study Commission. Writer and director Michael Schiffer supplied talents honed by decades of film writing, including Colors, Lean on Me, and Crimson Tide and the video game, Call of Duty. Together they raised the documentary from oral history to a story of how political intrigue and leadership saved the state’s groundwater.
The idea for the film came from the late Jack DeBolske, who served 40 years as the executive director of the League of Arizona Cities and Towns and, simultaneously, created and led the Maricopa Association of Governments. He was at the table throughout the groundwater negotiations and a few years ago called Kathleen to ask about making a record of the event. He knew it was Arizona history worth saving.
Kathleen struggled with just how to record this history until Michael pushed her into co-producing a documentary, a process she knew nothing about. It was May 2015 when Kathleen began tracking down and interviewing her old friends and colleagues, including former U.S. Senator Jon Kyl and former Arizona Governor and U.S. Secretary of the Interior Bruce Babbitt. At that point, Michael took over the storytelling and directing to turn 20 hours of interviews and exhaustive searches of Arizona’s archives into an entertaining 30-minute story.
Kathleen’s only regret is that she didn’t make the film sooner. Several key players in the negotiations were already gone, but Kathleen interviewed Jack DeBolske for the film and he saw the final product before passing away in July 2017.
Living Another Critical Moment: While the protagonists of Groundwater: To enact a law for the common good were successful, the mission they began isn’t over. As the film points out, Arizona is once again at a point where compromise and leadership are needed to assure the state will continue to have reliable water supplies. Once again, during one of the driest winters in the Southwest’s recent history, the state’s biggest political players are around the table negotiating how best to protect water supplies for the common good. Once again, a positive outcome seems difficult to imagine, which is why recording our history is so important. Groundwater: To enact a law for the common good acts as a warning, a guide and a testament that sometimes the impossible is possible.
Photo: Kathleen Ferris with the late Jack DeBoske (left) and the late Bill Stephens
For 49 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.
Much of the water we use comes from the ground. Learn more about the importance of groundwater, the threats to its safety, and how to protect its sources during Groundwater Awareness Week.
Water is one of the world’s most precious resources. People use water every day for many activities, such as drinking, bathing, recreation, agriculture, cooling, manufacturing, and medical uses. Although water plays an essential role in everyday life, many people don’t realize that much of their water comes from the ground.
Groundwater is water found below the earth’s surface in spaces between rock and soil. Surface water is water that collects above the earth’s surface, such as streams, rivers, lakes, or oceans. Thirty percent of all the fresh water on Earth is groundwater, while the other 70% is surface water. Groundwater supplies water to wells and springs and is an important source of water for public water systems and private wells in the United States.
An estimated 145 million Americans get their tap water from a groundwater source.
All groundwater sources should be protected from contamination (germs and harmful chemicals).
Protecting the safety of groundwater is an important priority for countries throughout the world, including the United States. Most of the time, U.S. groundwater is safe to use. However, groundwater sources can become contaminated with germs, such as bacteria, viruses, and parasites, and chemicals, such as those used in fertilizers and pesticides. Contaminated groundwater can make people sick.
Water infrastructure requires regular maintenance.
Groundwater sometimes contains naturally present germs and harmful chemicals from the environment, such as arsenic and radon. More often, however, human activities contaminate ground water. These human causes can include incorrect use of fertilizers and pesticides; poorly situated, constructed, or maintained septic systems; improper removal or storage of wastes; mining and construction; and chemical spills at work sites.
Contamination of groundwater systems can lead to outbreaks of disease. Previous outbreaks have occurred either because the groundwater was untreated or because of problems with water treatment. The most common germs identified in groundwater outbreaks include:
Other germs that cause outbreaks from groundwater include Cryptosporidium(a parasite), E. coli (a bacterium), and assorted viruses. From 2009 to 2017, 96 outbreaks linked to groundwater systems were reported to CDC.
The presence of germs and harmful chemicals in our groundwater can lead to health problems, including diarrhea, reproductive problems, and nervous system disorders. Infants, young children, pregnant women, the elderly, and people whose immune systems are weakened because of HIV/AIDS, chemotherapy, or transplant medicines may be more likely to get sick from certain germs and chemicals.
Concerns for groundwater contaminants led the U.S. Environmental Protection Agency (EPA) and individual states to develop regulations to protect public water systems, such as the 2006 Ground Water Ruleexternal icon.
One-third of Americans — more than 102 million people — get their drinking water from public water systems that use groundwater. The EPA regulates drinking water quality in public water systems. You can find out more about your local drinking water quality and possible contaminants by viewing your Consumer Confidence Report (CCR), which most utility companies are required to provide to customers.
Private Wells
An estimated 43 million Americans get their water from private groundwater wells, which are not subject to EPA regulations. Private groundwater wells can provide safe, clean water. However, contamination that can cause sickness also can occur in well water. If you have a well, you should take steps to protect it and have the water tested annually to make sure your water is safe from harmful germs and chemicals. State and local health departments provide information to help well users protect their drinking water.
As homeowners look for alternatives to city water, private wells are becoming a popular option. Well water is a topic of discussion that has been recurring in recent years and it has become the hot subject of different studies to determine its benefits. Well water may vary in quality and water volume but unlike local water systems, it is direct ground water, which does not go through chemical filtering before consumption. The natural state of the well water, great taste, environmental friendliness, and purity are benefits of well water. Following are some secret health benefits that you get from drinking well water.
1. Helps in weight loss
Drinking water is a great way to lose weight. When you drink enough water each day, it can help you to shed pounds or to maintain your weight. When you drink well water, you avoid the harmful chemicals present in regular water and the fact that the water tastes great means that you can drink plenty of it. Drinking water helps you to feel full, preventing you from overeating. In many cases, the body interprets the feeling of dehydration as hunger and drinking water can be the solution you need.
2. Aids in maintaining a healthy heart
You can reduce your risk of having a heart attack by drinking water. According to research, people who drink adequate amounts of water each day are less likely to suffer from heart attacks. Apart from helping with metabolism, hydration and other factors, it helps to flush out toxins, which cause illness from the body. Drinking water is definitely worth it when it comes to protecting your heart. Well water has a cleaner taste making it more drinkable and you will not find it difficult to stay hydrated.
3. Enhances brain function
Drinking water affects the brain and it can help you to think clearly. Research has shown that this zero-calorie essential drink can actually help to make you smarter. The body is made up of 70 percent water, it needs water in order to function at optimum level, and this includes the brain. When you are properly hydrated, you are more focused. Most people will find that the moment they start to feel dehydrated their short-term memory is affected.
4. Promotes healthy looking skin
If you want your skin to look great, drink plenty of water. Water helps to hydrate the skin giving it the beautiful and youthful glow. The water also helps to get rid of toxins that affect the skin texture and you will not have to deal with different skin conditions.
5. Reduces muscle and joint inflammation
If you suffer from joint and muscle inflammation, drinking water can help you to find relief. The water helps to reduce pain by producing much needed lubrication. It also helps to ensure that your body absorbs essential nutrients from the food that you consume.
Many homes across the country have water wells and they enjoy the ground water that is not subject to the chlorination process. Using well water also has financial benefits and getting the system up and running is relatively inexpensive and easy to implement. Well testing is important to ensure that your water is safe and free from contamination.
As homeowners look for alternatives to city water, private wells are becoming a popular option. Well water is a topic of discussion that has been recurring in recent years and it has become the hot subject of different studies to determine its benefits. Well water may vary in quality and water volume but unlike local water systems, it is direct ground water, which does not go through chemical filtering before consumption. The natural state of the well water, great taste, environmental friendliness, and purity are benefits of well water. Following are some secret health benefits that you get from drinking well water.
1. Helps in weight loss
Drinking water is a great way to lose weight. When you drink enough water each day, it can help you to shed pounds or to maintain your weight. When you drink well water, you avoid the harmful chemicals present in regular water and the fact that the water tastes great means that you can drink plenty of it. Drinking water helps you to feel full, preventing you from overeating. In many cases, the body interprets the feeling of dehydration as hunger and drinking water can be the solution you need.
2. Aids in maintaining a healthy heart
You can reduce your risk of having a heart attack by drinking water. According to research, people who drink adequate amounts of water each day are less likely to suffer from heart attacks. Apart from helping with metabolism, hydration and other factors, it helps to flush out toxins, which cause illness from the body. Drinking water is definitely worth it when it comes to protecting your heart. Well water has a cleaner taste making it more drinkable and you will not find it difficult to stay hydrated.
3. Enhances brain function
Drinking water affects the brain and it can help you to think clearly. Research has shown that this zero-calorie essential drink can actually help to make you smarter. The body is made up of 70 percent water, it needs water in order to function at optimum level, and this includes the brain. When you are properly hydrated, you are more focused. Most people will find that the moment they start to feel dehydrated their short-term memory is affected.
4. Promotes healthy-looking skin
If you want your skin to look great, drink plenty of water. Water helps to hydrate the skin giving it the beautiful and youthful glow. The water also helps to get rid of toxins that affect the skin texture and you will not have to deal with different skin conditions.
5. Reduces muscle and joint inflammation
If you suffer from joint and muscle inflammation, drinking water can help you to find relief. The water helps to reduce pain by producing much needed lubrication. It also helps to ensure that your body absorbs essential nutrients from the food that you consume.
Many homes across the country have water wells and they enjoy the ground water that is not subject to the chlorination process. Using well water also has financial benefits and getting the system up and running is relatively inexpensive and easy to implement. Well testing is important to ensure that your water is safe and free from contamination.
Groundwater, water that occurs below the surface of Earth, where it occupies all or part of the void spaces in soils or geologic strata. It is also called subsurface water to distinguish it from surface water, which is found in large bodies like the oceans or lakes or which flows overland in streams. Both surface and subsurface water are related through the hydrologic cycle (the continuous circulation of water in the Earth-atmosphere system).
Most groundwater comes from precipitation. Precipitation infiltrates below the ground surface into the soil zone. When the soil zone becomes saturated, water percolates downward. A zone of saturation occurs where all the interstices are filled with water. There is also a zone of aeration where the interstices are occupied partially by water and partially by air. Groundwater continues to descend until, at some depth, it merges into a zone of dense rock. Water is contained in the pores of such rocks, but the pores are not connected and water will not migrate. The process of precipitation replenishing the groundwater supply is known as recharge. In general, recharge occurs only during the rainy season in tropical climates or during winter in temperate climates. Typically, 10 to 20 percent of the precipitation that falls to the Earth enters water-bearing strata, which are known as aquifers.
28%
OF EARTH’S FRESHWATER IS GROUNDWATER.
Groundwater is constantly in motion. Compared to surface water, it moves very slowly, the actual rate dependent on the transmissivity and storage capacity of the aquifer. Natural outflows of groundwater take place through springs and riverbeds when the groundwater pressure is higher than atmospheric pressure in the vicinity of the ground surface. Internal circulation is not easily determined, but near the water table, the average cycling time of water maybe a year or less, while in deep aquifers it may be as long as thousands of years.
Credit: Encyclopædia Britannica, Inc.
Groundwater plays a vital role in the development of arid and semiarid zones, sometimes supporting vast agricultural and industrial enterprises that could not otherwise exist. It is particularly fortunate that aquifers antedating the formation of deserts remain unaffected by increases in aridity with the passage of time. Withdrawal, however, will deplete even the largest of groundwater basins so that development based on the existence of aquifers can be only temporary at best.
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A vast amount of groundwater is distributed throughout the world, and a large number of groundwater reservoirs are still underdeveloped or uninvestigated. Scientists estimate that some 5.97 quintillion gallons (22.6 million cubic km [5.4 million cubic miles]) of groundwater reside in the upper 2 km (1.2 miles) of Earth’s surface. The most frequently investigated or exploited groundwater reservoirs are of the unconsolidated clastic (mainly sand and gravel) or carbonate hard rock type found in alluvial valleys and coastal plains under temperate or arid conditions.
Though some groundwater dissolves substances from rocks and may contain traces of old seawater, most groundwater is free of pathogenic organisms, and purification for domestic or industrial use is not necessary. Furthermore, groundwater supplies are not seriously affected by short droughts and are available in many areas that do not have dependable surface water supplies. However, aquifers and other groundwater supplies are at risk of chemical pollution from fracking, agricultural chemicals, leaking or unfit landfills and septic tanks, and other point and nonpoint sources of pollution. Such contamination can render groundwater unfit for use and is expensive and difficult to clean up.
Groundwater, water that occurs below the surface of Earth, where it occupies all or part of the void spaces in soils or geologic strata. It is also called subsurface water to distinguish it from surface water, which is found in large bodies like the oceans or lakes or which flows overland in streams. Both surface and subsurface water are related through the hydrologic cycle (the continuous circulation of water in the Earth-atmosphere system).
Most groundwater comes from precipitation. Precipitation infiltrates below the ground surface into the soil zone. When the soil zone becomes saturated, water percolates downward. A zone of saturation occurs where all the interstices are filled with water. There is also a zone of aeration where the interstices are occupied partially by water and partially by air. Groundwater continues to descend until, at some depth, it merges into a zone of dense rock. Water is contained in the pores of such rocks, but the pores are not connected and water will not migrate. The process of precipitation replenishing the groundwater supply is known as recharge. In general, recharge occurs only during the rainy season in tropical climates or during winter in temperate climates. Typically, 10 to 20 percent of the precipitation that falls to the Earth enters water-bearing strata, which are known as aquifers.
Groundwater is constantly in motion. Compared to surface water, it moves very slowly, the actual rate dependent on the transmissivity and storage capacity of the aquifer. Natural outflows of groundwater take place through springs and riverbeds when the groundwater pressure is higher than atmospheric pressure in the vicinity of the ground surface. Internal circulation is not easily determined, but near the water table the average cycling time of water may be a year or less, while in deep aquifers it may be as long as thousands of years.
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Groundwater plays a vital role in the development of arid and semiarid zones, sometimes supporting vast agricultural and industrial enterprises that could not otherwise exist. It is particularly fortunate that aquifers antedating the formation of deserts remain unaffected by increases in aridity with the passage of time. Withdrawal, however, will deplete even the largest of groundwater basins so that development based on the existence of aquifers can be only temporary at best.
Study the efforts of the Namibian government to locate groundwater by using a specially equipped helicopter
Learn about efforts to locate groundwater in Namibia, where fresh water is scarce.
A vast amount of groundwater is distributed throughout the world, and a large number of groundwater reservoirs are still underdeveloped or uninvestigated. Scientists estimate that some 5.97 quintillion gallons (22.6 million cubic km [5.4 million cubic miles]) of groundwater reside in the upper 2 km (1.2 miles) of Earth’s surface. The most frequently investigated or exploited groundwater reservoirs are of the unconsolidated clastic (mainly sand and gravel) or carbonate hardrock type found in alluvial valleys and coastal plains under temperate or arid conditions.
Though some groundwater dissolves substances from rocks and may contain traces of old seawater, most groundwater is free of pathogenic organisms, and purification for domestic or industrial use is not necessary. Furthermore, groundwater supplies are not seriously affected by short droughts and are available in many areas that do not have dependable surface water supplies. However, aquifers and other groundwater supplies are at risk of chemical pollution from fracking, agricultural chemicals, leaking or unfit landfills and septic tanks, and other point and nonpoint sources of pollution. Such contamination can render groundwater unfit for use and is expensive and difficult to clean up.
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