Showing posts with label groundwater. Show all posts
Showing posts with label groundwater. Show all posts

Wednesday, July 8, 2015

Groundwater from aquifers important factor in food security

A press release from the University of Illinois News Bureau: Thirsty cities, fields and livestock drink deeply from aquifers, natural sources of groundwater. But a study of three of the most-tapped aquifers in the United States shows that overdrawing from these resources could lead to difficult choices affecting not only domestic food security but also international markets.

University of Illinois professors of civil and environmental engineering Ximing Cai and Megan Konar, along with graduate student Landon Marston and Lehigh University professor Tara Troy, studied groundwater consumption from three main aquifer systems. Reliance on these aquifers intensified so much from 2000 to 2008 that it accounted for 93 percent of groundwater depletion in the U.S. They published their findings in the Proceedings of the National Academy of Sciences.

The U.S. Geological Survey identifies the Central Valley aquifer in California, the High Plains aquifer in the Great Plains states, and the Mississippi Embayment aquifer in the lower Midwest as being managed unsustainably, which means that water is being extracted from the aquifer faster than it is replenishing. ... The researchers tracked water consumption from the aquifers to see where the water was going, both in terms of geography and usage. For example, when water was used to irrigate a crop, the researchers tracked where those crops were shipped.

“When we think of water, we think of direct water, the water that comes out of our faucets. But we actually use a lot of embodied water in our everyday lives – the water footprint to produce a product,” Konar said. “We looked at the water implicitly being transferred between states and countries in the products.”

The researchers found that the vast majority – 91 percent – of embodied groundwater from these three aquifers stayed within the U.S. The remaining 9 percent was exported internationally. They identified the states most heavily reliant on each aquifer, and the breakdown of what was produced using water from each aquifer. For example, the largest percentage of water from the High Plains aquifer irrigated grains, while the largest contribution from the Central Valley aquifer in California went to producing meat...

A groundwater irrigation pump in the UK, shot by John Poyser, Wikimedia Commons via Geograph UK, under the Creative Commons Attribution-Share Alike 2.0 Generic license

Wednesday, June 17, 2015

Groundwater resources draining fast, NASA data show

Timothy Cama in the Hill: Humans are depleting a large portion of the world’s groundwater resources, and they are not being naturally refilled, researchers said. The scientists at the University of California Irvine used data from National Aeronautics and Space Administration (NASA) satellites to determine drainage of the world’s largest groundwater aquifers in recent years.

They found that a third of the 37 major aquifers were either worse off in 2013 than in 2003 or were highly stressed. “Available physical and chemical measurements are simply insufficient,” Jay Famiglietti, the principal researcher on the project, said in a Tuesday statement. Famiglietti is both a UC Irvine professor and the top water scientist at NASA’s Jet Propulsion Laboratory.

“Given how quickly we are consuming the world’s groundwater reserves, we need a coordinated global effort to determine how much is left,” he said.

The paper was published Tuesday in the journal Water Resources Research. It is the first to use data from NASA’s Gravity Recovery and Climate Experiment, or GRACE, satellite system, which detects changes in Earth’s gravity that can show groundwater levels.

It found that the most stressed aquifers were in extreme dry areas, whose residents and businesses have leaned most heavily on groundwater....

A bore well pump in India, shot by ABHIJEET, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Monday, November 17, 2014

Groundwater warming up in synch

Peter Ruegg at ETH in Zurich: Global warming stops at nothing – not even the groundwater, as a new study by researchers from ETH Zurich and KIT reveals: the groundwater’s temperature profiles echo those of the atmosphere, albeit damped and delayed.

For their study, the researchers were able to fall back on uninterrupted long-term temperature measurements of groundwater flows around the cities of Cologne and Karlsruhe, where the operators of the local waterworks have been measuring the temperature of the groundwater, which is largely uninfluenced by humans, for forty years. This is unique and a rare commodity for the researchers. “For us, the data was a godsend,” stresses Peter Bayer, a senior assistant at ETH Zurich’s Geological Institute. Even with some intensive research, they would not have been able to find a comparable series of measurements. Evidently, it is less interesting or too costly for waterworks to measure groundwater temperatures systematically for a lengthy period of time. “Or the data isn’t digitalised and only archived on paper,” suspects the hydrogeologist.

Based on the readings, the researchers were able to demonstrate that the groundwater is not just warming up; the warming stages observed in the atmosphere are also echoed. “Global warming is reflected directly in the groundwater, albeit damped and with a certain time lag,” says Bayer, summarising the main results that the project has yielded. The researchers published their study in the journal Hydrology and Earth System Sciences.

The data also reveals that the groundwater close to the surface down to a depth of around sixty metres has warmed up statistically significantly in the course of global warming over the last forty years. This water heating follows the warming pattern of the local and regional climate, which in turn mirrors that of global warming.

The groundwater reveals how the atmosphere has made several temperature leaps at irregular intervals. These “regime shifts” can also be observed in the global climate, as the researchers write in their study. Bayer was surprised at how quickly the groundwater responded to climate change....

The Portuguese cistern of El Jadida, shot by Fulvio Attisani, Wikimedia Commons, under the Creative Commons 3.0 license

Sunday, November 9, 2014

Ground water depletion driving global conflicts

Chris Arsenault at the Thomson Reuters Foundation: Global ground water supplies, crucial for sustaining agriculture, are being depleted at an alarming rate with dangerous security implications, a leading scientist said.

"It's a major cause for concern because most of the places where it (ground water depletion) is happening are major food producing regions," James Famiglietti, a University of California professor who conducts research for the National Aeronautics and Space Administration (NASA), said in an interview with the Thomson Reuters Foundation. "India is the worst off, followed by the Middle East, and the U.S. is probably number three ... the Chinese, particularly on the north China plain, are more water limited than people believe."

Famiglietti's conclusions are based on his latest research paper "The global ground water crisis" published in the journal Nature Climate Change last month. The study uses analysis of satellite images to warn that ground water in many of the world's largest aquifers is being exploited at a far faster rate than it can be naturally replenished.

Farming accounts for more than 80 percent of the United States' water use, according to the U.S. Department of Agriculture, and the figures are similar globally. Famiglietti has been called to the Pentagon a number of times to discuss the potential impact of groundwater scarcity with leading military planners....

A dried up pool at Fairburn Ings, shot by Bernard Bradley, Wikimedia Commons via Geograph UK, under the Creative Commons 2.0 license

Monday, August 4, 2014

California drought: 'May have to migrate people'

Mark Koba in CNBC: It's going from worse to worst each week in California. Suffering in its third year of drought, more than 58 percent of the state is currently in "exceptional drought" stage, according to the latest U.S. Drought Monitor map. That marks a huge jump from just seven days ago, when about 36 percent of the state was categorized that way.

Exceptional drought, the most extreme category, indicates widespread crop and pasture losses and shortages of water in reservoirs, streams and wells.

If the state continues on this path, there may have to be thoughts about moving people out, said Lynn Wilson, academic chair at Kaplan University and who serves on the climate change delegation in the United Nations.

"Civilizations in the past have had to migrate out of areas of drought," Wilson said. "We may have to migrate people out of California." Wilson added that before that would happen, every option such as importing water to the state would likely occur— but "migration can't be taken off the table."

The drought has nearly depleted the state's surface water—which is seen being reduced by about one-third this year. Farmers in California have turned to groundwater to keep crops irrigated. That has led to fears of depleted groundwater in the years ahead if that continues, according to a report released earlier this month.

"So far, groundwater has helped get crops to market and keep food prices in line," said Jay Lund, director of the Center for Watershed Sciences at the University of California, Davis, which released the report....

The July 29, 2014 US Drought Monitor for the western US. Red is "extreme drought" and brown is "exceptional drought"

Friday, July 25, 2014

Western US states using up groundwater at an alarming rate

Eric Hand in Science:  For the past 14 years, drought has afflicted the Colorado River Basin, and one of the most visible signs has been the white bathtub rings around the red rocks of Lake Mead and Lake Powell, the two biggest dammed lakes on the river. But there is also an invisible bathtub being emptied, below ground. A new study shows that ground water in the basin is being depleted six times faster than surface water. The groundwater losses, which take thousands of years to be recharged naturally, point to the unsustainability of exploding population centers and water-intensive agriculture in the basin, which includes most of Arizona and parts of Colorado, California, Nevada, Utah, New Mexico, and Wyoming.

The study is the first to identify groundwater depletion across the entire Colorado River Basin, and it brings attention to a neglected issue, says Leonard Konikow, ahydrogeologist emeritus at the U.S. Geological Survey in Reston, Virginia, who was not involved with the work. Because ground water feeds many of the streams and rivers in the area, Konikow predicts that more of them will run dry. He says water pumping costs will rise as farmers—who are the biggest users of ground water—have to drill deeper and deeper into aquifers. “It’s disconcerting,” Konikow says. “Boy, water managers gotta do something about this, because this can’t go on forever.”

...Famiglietti says it makes sense that cities and farmers turn from surface water to ground water during drought. But he is surprised by the magnitude of the loss. The groundwater depletion rate is twice that in California’s Central Valley, another place famous for heavy groundwater use.

Regulation and monitoring of groundwater extraction are rare. The basin’s surface water is apportioned precisely under the Colorado River Compact, a 1922 agreement among seven states. In contrast, groundwater extraction is often the local right of the landowner. “If you own the property, you can drill a well and pump as much as you want,” Famiglietti says. “That’s just the way it is.”...

The Mark Wilmer Pumping Plant on Lake Havasu, on the border between Arizona and California, near Lake Havasu City, Arizona. Shot by Kjkolb, Wikimedia Commons,  under the Creative Commons Attribution-Share Alike 3.0 Unported license

Sunday, July 20, 2014

The rate at which groundwater reservoirs are being depleted is increasing

AlphaGalileo via Goethe University, Frankfurt am Main: In what parts of the world and to what degree have
groundwater reservoirs been depleted over the past 50 years? The Frankfurt
hydrologist Prof. Petra Döll has been researching this using the global water
model WaterGAP. She has arrived at the most reliable estimate to date by taking
into consideration processes which are important in dry regions of the world.
The values calculated were compared with monitoring data from many different
wells and data from the GRACE satellites. These satellites measure changes in
the Earth's gravity field. Döll has come to the conclusion that the rate at
which groundwater reservoirs are being depleted is increasing, but that the
rate is not as high as previously estimated.

90 percent of water consumption is due to irrigation for
farming purposes. Only the comparatively small remainder is used for potable
water and industrial production. As an example, 40 percent of the cereals produced
around the world is irrigated. However, in many cases this results in increased
scarcity of water resources and puts a burden on ecosystems. In dry regions,
the amount taken from groundwater reservoirs can easily exceed the amount being
replenished, so that the groundwater reservoir is overused and depleted.

"By comparing the modelled and measured values of
groundwater depletion, we were able for the first time to show on a global
scale that farmers irrigate more sparingly in regions where groundwater
reservoirs are being depleted. They only use about 70 percent of the optimal irrigation amounts", explains Petra Döll from the Institute of Physical
Geography at the Goethe
University.

The rate at which the Earth's groundwater reservoirs are
being depleted is constantly increasing. Annual groundwater depletion during
the first decade of this century was twice as high as it was between 1960 and
2000. India, the USA, Iran, Saudi Arabia and China are the countries with the
highest rates of groundwater depletion. About 15 percent of global groundwater
consumption is not sustainable, meaning that it comes from non-renewable
groundwater resources. On the Arabian Peninsula, in Libya, Egypt, Mali,
Mozambique and Mongolia, over 30 percent of groundwater consumption is from
non-renewable groundwater.

The new estimate of global groundwater depletion is 113,000
million cubic meters per year for the period from 2000 to 2009, which is lower
than previous, widely varying estimates. This can be considered to be the most reliable value to date, since it is based on improved groundwater consumption
data which takes the likely deficit irrigation into account, and since the
model results correlate well with independent comparative data....

A helical step well, shot by Ankush.sabharwal, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Wednesday, June 18, 2014

Breakthrough provides picture of underground water

Rob Jordan at the Stanford University News Service: ... In a development that could revolutionize the management of precious groundwater around the world, Stanford researchers have pioneered the use of satellites to accurately measure levels of water stored hundreds of feet below ground. Their findings were published recently in Water Resources Research.

Groundwater provides 25 to 40 percent of all drinking water worldwide, and is the primary source of freshwater in many arid countries, according to the National Groundwater Association. About 60 percent of all withdrawn groundwater goes to crop irrigation. In the United States, the number is closer to 70 percent. In much of the world, however, underground reservoirs or aquifers are poorly managed and rapidly depleted due to a lack of water-level data. Developing useful groundwater models, availability predictions and water budgets is very challenging.

...Until now, the only way a water manager could gather data about the state of water tables in a watershed was to drill monitoring wells. The process is time and resource intensive, especially for confined aquifers, which are deep reservoirs separated from the ground surface by multiple layers of impermeable clay. Even with monitoring wells, good data is not guaranteed. Much of the data available from monitoring wells across the American West is old and of varying quality and scientific usefulness. Compounding the problem, not all well data is openly shared.

...The basic concept: Satellites that use electromagnetic waves to monitor changes in the elevation of Earth's surface to within a millimeter could be mined for clues about groundwater. The technology, Interferometric Synthetic Aperture Radar (InSAR), had previously been used primarily to collect data on volcanoes, earthquakes and landslides.

With funding from NASA, the researchers used InSAR to make measurements at 15 locations in Colorado's San Luis Valley, an important agricultural region and flyway for migrating birds. Based on observed changes in Earth's surface, the scientists compiled water-level measurements for confined aquifers at three of the sampling locations that matched the data from nearby monitoring wells....

An irrigation system near Monterey, California, shot by Brendel, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license 

Friday, April 18, 2014

India's worsening water crisis

Ram Mashru in the Diplomat: In northern India, groundwater supplies are being depleted faster than natural processes can replenish them. According to The World Bank, India is the largest user of ground water in the world, after China. If something is not done soon, an estimated 114 million Indians will soon face desperate domestic, agricultural and industrial shortages.

What is causing this? “Human activities”: primarily wasteful water use (mainly agricultural over-exploitation), a lack of sustainable water-management policies and insufficient public investment. These failings have each been exacerbated by rapid population growth, increasing population density and climate change.

South Asia is a desperately water-insecure region, and India’s shortages are part of a wider continental crisis. According to a recent report authored by UN climate scientists, coastal areas in Asia will be among the worst affected by climate change. Hundreds of millions of people across East, Southeast and South Asia, the report concluded, will be affected by flooding, droughts, famine, increases in the costs of food and energy, and rising sea levels.

Groundwater serves as a vital buffer against the volatility of monsoon rains, and India’s falling water table therefore threatens catastrophe. 60 percent of north India’s irrigated agriculture is dependent on ground water, as is 85 percent of the region’s drinking water. The World Bank predicts that India only has 20 years before its aquifers will reach “critical condition” – when demand for water will outstrip supply – an eventuality that will devastate the region’s food security, economic growth and livelihoods....

Detail of Chand Baori, a step well in Abhaneri, Rajasthan, India, shot by rajkumar1220, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license 

Monday, February 17, 2014

Why global water shortages pose threat of terror and war

Suzanne Goldenberg in the Guardian (UK): On 17 January, scientists downloaded fresh data from a pair of Nasa satellites and distributed the findings among the small group of researchers who track the world's water reserves. At the University of California, Irvine, hydrologist James Famiglietti looked over the data from the gravity-sensing Grace satellites with a rising sense of dread.

...There are other shock moments ahead – and not just for California – in a world where water is increasingly in short supply because of growing demands from agriculture, an expanding population, energy production and climate change.

Already a billion people, or one in seven people on the planet, lack access to safe drinking water. Britain, of course, is currently at the other extreme. Great swaths of the country are drowning in misery, after a series of Atlantic storms off the south-western coast. But that too is part of the picture that has been coming into sharper focus over 12 years of the Grace satellite record. Countries at northern latitudes and in the tropics are getting wetter. But those countries at mid-latitude are running increasingly low on water.

"What we see is very much a picture of the wet areas of the Earth getting wetter," Famiglietti said. "Those would be the high latitudes like the Arctic and the lower latitudes like the tropics. The middle latitudes in between, those are already the arid and semi-arid parts of the world and they are getting drier."

On the satellite images the biggest losses were denoted by red hotspots, he said. And those red spots largely matched the locations of groundwater reserves. "Almost all of those red hotspots correspond to major aquifers of the world. What Grace shows us is that groundwater depletion is happening at a very rapid rate in almost all of the major aquifers in the arid and semi-arid parts of the world."

The Middle East, north Africa and south Asia are all projected to experience water shortages over the coming years because of decades of bad management and overuse....

NASA satellite image of agricultural fields in northern Saudi Arabia

Sunday, February 9, 2014

When drought occurs, fracking and farming collide

Mark Jaffe in the Denver Post: The move to tap petroleum-rich shale reserves in some of the country's driest regions, including Colorado, may be setting up a battle between oil and water. The water is needed for hydraulic fracturing, a process that pumps millions of gallons of sand and water into a well to crack the hard shale and release oil and gas.

Nearly half of the 39,294 reported "fracked" wells drilled in the U.S. since 2011 are in regions with high or extreme water stress, according to a report by Ceres, an investor and environmental-advocacy group. In Colorado, Ceres found that 97 percent of the wells are being drilled in highly or extremely highly water-stressed areas, such as the Denver-Julesburg Basin.

In 2013, two-thirds of the 1,839 new wells in Colorado were drilled in Weld County, the heart of the DJ Basin. "Fracking isn't using a lot of water yet, but it is a new use," said Gary Wockner, director of the Save the Colorado River Campaign. "If it gets embedded in the economy, other uses won't be able to compete."

The water demands for fracking — a process used since the 1940s — have soared with the advent of horizontal wells, which can stretch 2 miles underground....

Water tanks near a fracking site, shot by Joshua Doubek, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Wednesday, October 23, 2013

Nitrogen fertilizer remains in soils and leaks towards groundwater for decades

Terra Daily via SPX: Nitrogen fertilizer applied to crops lingers in the soil and leaks out as nitrate for decades towards groundwater - "much longer than previously thought," scientists in France and at the University of Calgary say in a new study. Thirty years after synthetic nitrogen (N) fertilizer had been applied to crops in 1982, about 15 per cent of the fertilizer N still remained in soil organic matter, the scientists found.

After three decades, approximately 10 per cent of the fertilizer N had seeped through the soil towards the groundwater and will continue to leak in low amounts for at least another 50 years. The study was led by researcher Mathieu Sebilo at the Universite Pierre et Marie Currie in Paris, France, and by Bernhard Mayer in the U of C's Department of Geoscience, and included several research organizations in France.

Their paper, "Long-term fate of nitrate fertilizer in agricultural soils," was published this week in the Proceedings of the National Academy of Sciences of the United States of America. The findings show that losses of fertilizer N towards the groundwater occur at low rates but over many decades, says Mayer, U of C professor of geochemistry and head of the Applied Geochemistry Group.

That means it could take longer than previously thought to reduce nitrate contamination in groundwater, including in aquifers that supply drinking water in North America and elsewhere, he says. "There's a lot of fertilizer nitrogen that has accumulated in agricultural soils over the last few decades which will continue to leak as nitrate towards groundwater," Mayer says....

From Geoff Ruth's  High School Earth Science 1-13.pdf (page 493), Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Wednesday, August 21, 2013

Sinking cities in Indonesia caused by groundwater and gas extraction

Rosenstiel School of Marine &Atmospheric Sciences News: Jakarta and several other major Indonesia cities are sinking at alarming rates of up to 22 cm per year, according to a new study by scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science. This rapid land subsidence of major cities, due to extraction of groundwater for industrial use, is likely to put the densely populated coastal regions below sea level in less than two decades.

"Our study shows that some parts of Jakarta, and elsewhere in Indonesia, will be below sea level in less than 20 years if they don't stop pumping groundwater," said Rosenstiel School Professor Falk Amelung, a co-author of the study.

...The researchers attributed this rapid land subsidence to groundwater extraction in four major urban areas, including in the capital and largest city of Jakarta (population: 9.5 million), Bandung (population: 2.4 million), Pekalongan (population: 200,000), and Semarang (population: 1.5 million). Indonesia's municipal water supply serves only 25% of its more than 240 million people therefore the majority of the population and industries rely heavily on groundwater extraction for water. Land subsidence from gas field exploitation was also shown to occur near the Indonesian cities of Lhokseumawe and in the Sidoarjo regency.

Unlike Venice, which is sinking at a rate of 2 to 3 millimeters per year, heavily developed regions of Indonesia, including in Jakarta and five other major cities are sinking at rates of tens of centimeters per year.

..."Since these cities are close to sea level and because the subsidence is extremely rapid, the societal impacts could be huge, both in terms of water resources and sinking of the land relative to the ocean," said Chaussard. "Understanding of the processes involved and continuing the monitoring are thus critical for mitigation purposes."....

An aerial view of north Jakarta, shot by Amelia Guo, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

Sunday, July 28, 2013

Potential well water contamination highest near natural gas drilling

University of Texas at Arlington News Center: A new study of 100 private water wells in and near the Barnett Shale showed elevated levels of potential contaminants such as arsenic and selenium closest to natural gas extraction sites, according to a team of researchers that was led by UT Arlington associate professor of chemistry and biochemistry Kevin Schug.

Brian Fontenot, who earned his Ph.D. in quantitative biology from UT Arlington, worked with Kevin Schug, UT Arlington associate professor of chemistry and biochemistry, and a team of researchers to analyze samples from 100 private water wells.

The results of the North Texas well study were published online by the journal Environmental Science & Technology Thursday. The peer-reviewed paper focuses on the presence of metals such as arsenic, barium, selenium and strontium in water samples. Many of these heavy metals occur naturally at low levels in groundwater, but disturbances from natural gas extraction activities could cause them to occur at elevated levels.

“This study alone can’t conclusively identify the exact causes of elevated levels of contaminants in areas near natural gas drilling, but it does provide a powerful argument for continued research,” said Brian Fontenot, a UT Arlington graduate with a doctorate in quantitative biology and lead author on the new paper.

He added: “We expect this to be the first of multiple projects that will ultimately help the scientific community, the natural gas industry, and most importantly, the public, understand the effects of natural gas drilling on water quality.”...

A far view of a fracking operation undetaken by Halliburton, shot by Joshua Doubek, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Monday, February 4, 2013

‘Mining’ groundwater could fuel climate change, study finds

Randy Shore in the Vancouver Sun: The world’s increasing reliance on deep groundwater for agricultural, residential and industrial use is fuelling crop-damaging soil salinity and depleting the world’s supply of fresh water, according to a new study in the journal Nature Climate Change.

Low-lying crop lands here in B.C. could be threatened, as water brought to the surface for human needs compounds the rise in sea levels predicted by climate change models.

The most immediate impact of over-use of groundwater will be on our ability to feed ourselves, according to one of the study’s co-authors Diana Allen, a professor of earth sciences at Simon Fraser University.

About half of British Columbia’s food supply is imported, much of it from California, which has suffered from drought and is projected to become even more reliant on groundwater as precipitation declines due to climate change.

“Water security and food security are inextricably linked,” Allen said. “And the resources that are available in our most productive agricultural areas are already showing signs of water stress.”...

Irrigation from an aquifer in the Egyptian Sahara, view from NASA

Sunday, November 11, 2012

'Groundwater inundation' doubles previous predictions of flooding with future sea level rise

Science Codex: Scientists from the University of Hawaii at Manoa (UHM) published a study today in Nature Climate Change showing that besides marine inundation (flooding), low-lying coastal areas may also be vulnerable to "groundwater inundation," a factor largely unrecognized in earlier predictions on the effects of sea level rise (SLR). Previous research has predicted that by the end of the century, sea level may rise 1 meter. Kolja Rotzoll, Postdoctoral Researcher at the UHM Water Resources Research Center and Charles Fletcher, UHM Associate Dean, found that the flooded area in urban Honolulu, Hawaii, including groundwater inundation, is more than twice the area of marine inundation alone.

Specifically, a 1-meter rise in sea level would inundate 10% of a 1-km wide heavily urbanized area along the shoreline of southern Oahu and 58% of the total flooded area is due to groundwater inundation.

"With groundwater tables near the ground surface, excluding groundwater inundation may underestimate the true threat to coastal communities," said Rotzoll, lead author of the study.

"This research has implications for communities that are assessing options for adapting to SLR. Adapting to marine inundation may require a very different set of options and alternatives than adapting to groundwater inundation," states Fletcher, Principle Investigator on the grant that funded the research.

Groundwater inundation is localized coastal-plain flooding due to a simultaneous rise of the groundwater table with sea level. Groundwater inundation is an additional risk faced by coastal communities and environments before marine flooding occurs because the groundwater table in unconfined aquifers typically moves with the ocean surface and lies above mean sea level at some distance from the shoreline....

In 2004, Amala Place flooded. near Kanaha Beach, on Maui, shot by Forest & Kim Starr, Wikimedia Commons,  under the Creative Commons Attribution 3.0 Unported license

Wednesday, January 18, 2012

More valuable than gold

Dominic Feain in the Coffs Coast Advocate (Australia): A new warning calling for greater research into Australia's groundwater has been welcomed by locals concerned about the burgeoning coal seam gas industry on the Northern Rivers.

The statement, released yesterday by the National Centre for Groundwater Research and Training, describes Australia's underground water reserves as a "buried treasure" potentially more valuable to our future gross national product than gold, oil, wheat or coal. It states groundwater will become increasingly critical as the population grows and temperatures rise.

Environmental scientist Boudicca Cerese, from community group Kyogle Against Gas, said her primary concern had always been the lack of information and she believed the warning vindicated the call for a moratorium on the industry until "adequate regional hydro-geological studies" have been undertaken. "The critical thing it says is that the key to ground water management is knowledge - and I believe we have insufficient knowledge to be going ahead with any coal seam gas exploration," she said.

The centre's director, Professor Craig Simmons, says that ground-water makes up 97% of the world's fresh water, but he expected dependence upon it to grow as the pressure from population growth, climate change, mining, coal seam gas and agriculture intensified.

"In a future where rainfall cannot be relied on, groundwater represents Australia's national water security for the future," Prof Simmons said. "Where our national security is concerned, we should spare no effort to assure it....

Water bore and dam on a property in the Townsville district of Queensland, Australia, ca. 1902

Thursday, July 7, 2011

California groundwater management trickles up from local sources

Science Daily: In a typical year, California gets about 30 percent of its water from groundwater wells. Yet when it comes to managing this precious resource, the state of California relies on a mixed bag of more than 2,000 local water agencies with varying degrees of authority.

Critics say that this decentralized system leaves the state vulnerable to overdraft, which occurs when water is pumped out faster than replacement water is absorbed. But according to a new report published by Stanford University's Program on Water in the West, a surprising number of local water districts are taking on the challenge of groundwater protection, even without state leadership.

"Contrary to popular expectations, our report uncovers a treasure trove of innovative strategies for groundwater management in California," said the paper's author, Rebecca Nelson, a former Australian water lawyer who is now a graduate student in the Stanford Law School.

"The California legal framework for groundwater management is weak," Nelson said. "It doesn't compel local districts to do anything, so many of them don't. But there are these gems in the rough. This report highlights the work of some of these outstanding managers."

To evaluate how well groundwater is managed in California, Nelson first had to overcome the lack of basic information about groundwater management in the state. Because California lacks a centralized data clearinghouse, she had to contact more than 50 local districts and request copies of their groundwater management plans -- if they had any. "Maybe on two hands you could count the districts that acknowledge the environmental effects of over-pumping," Nelson said.

This lack of statewide data is a problem not only for researchers but also for local water agencies wishing to learn from each other and develop a comprehensive regional strategy, she said...

Approximate location of maximum subsidence in the United States identified by research efforts of Dr. Joseph F. Poland (pictured). Signs on pole show approximate altitude of land surface in 1925, 1955, and 1977. The site is in the San Joaquin Valley southwest of Mendota, California. The compaction of unconsolidated aquifer systems that can accompany excessive ground-water pumping is by far the single largest cause of subsidence. The overdraft of such aquifer systems has resulted in permanent subsidence and related ground failures. In aquifer systems that include semiconsolidated silt and clay layers (aquitards) of sufficient aggregate thickness, long-term ground-water-level declines can result in a vast one-time release of “water of compaction” from compacting aquitards, which manifests itself as land subsidence. US Geological Survey photographer