Saturday, March 22, 2008

Mining Water

(See also my articles Peak Water and The Emerging Global Freshwater Crisis in this blog.)

The term "mining water" is increasingly used to refer to the extraction of groundwater, usually by pumps, from underground aquifers. Get used to the term. At the rate we are polluting our surface water in lakes and rivers and the rate at which freshwater sources are drying up under the assault of global warming and human development it may soon be the only potential source of clean drinking water we or our children and grandchildren have left. It is an appropriate term in many ways.

Water is a finite resource that is constantly recycled - like the metal in beer cans - and many of the underground aquifers from which we extract it are non-replenishable, meaning once it is gone, like a vein of ore, it's time to shut off the pumps and go home or move on to another aqua-motherlode. Even those aquifers that are replenishable, however, have a long-established, generally-low rate at which they will replenish ("Water that enters an aquifer remains there for an average of 1,400 years, compared to only 16 days for rivers."[5]. Extract more water than the rate at which it will refill and you start the process of depleting, and possibly irreversibly damaging, the reservoir. The land over many aquifers that have been over-exploited shows clear signs of sinking and compression due to the underground void left as the water is extracted.

Changing weather patterns generally, and the more pronounced changes being brought on by global warming, and the persistent human habit of draining marshes and wetlands for development, many of which are the source of replenishment for underground aquifers, are also changing the rate at which many aquifers replenish, usually negatively. Unless aquifer replenishment rates are tracked with changes in the climate and local development ("The Yellow river in China, Colorado River in North America, and the Murray River in Australia are amongst the Earth's major rivers that are regularly sucked dry.")[1], those dependent on an aquifer for water may find their wells suddenly going dry even though they have not increased their water extraction.

There is another aspect to the term "mining water" that is particularly worrisome for the future. Water rights to surface water in most areas today require a water rights license, even if the water runs through or touches your property. That license spells out what source of water you have access to and how much water from that source you are permitted to use. If the term and concept of "mining water" works its way into government bureaucratic lexicon you may also need a license to access the groundwater beneath your own property - some jurisdictions already require it - a license that similarly specifies how much of that water you have a right to use. In international trade agreements, and in the conditions attached to IMF and Worldbank loans to developing countries, water services and water rights are a commodity that is increasingly required to be open for commercial trade. It is possible, as clean surface water sources become increasingly scarce, that your groundwater may become an important tradeable commodity for which you are going to have to compete against the highest commercial bidder. With the majority of aquifers already under pressure from over exploitation governments everywhere may decide that growing demand for commercial groundwater access is exactly why there is a need of government control and private access restriction.

For me, in addition, the term also has a strong personal meaning which, I believe, clearly illustrates a broader issue. The southeastern Ontario community I grew up in was a mining town. A mile southeast of home, the constantly-growing, flat-top mountain of slag clearly visible from anywhere in town and the surrounding area, there was a large, open-pit iron ore mine that was the town's main employer during my growing-up years. When they had tapped out the economically-recoverable iron - there was still plenty of iron but they would have had to go underground to get it - the mining company shut off the pumps that kept the pit from flooding and walked away. They even ripped up their rail line that once delivered tons of crude ore to Lake Ontario for shipping across the lake to a Pennsylvania processing facility. They left behind a massive hole in the ground over 600 feet deep and a mile across.

For the past forty years that "hole" has been filling up with clear, blue water, draining every aquifer in the area. Whether they are replenishable I don't know since no appropriate survey of local aquifers has ever been conducted, though they are currently being studied as part of a broader, provincial groundwater survey. There isn't a well within miles, nonetheless, that still has water in it. The community, fortunately, takes its municipal water from the river that runs through town but the water mains end at the town limits. The farmers and other rural residents in the area over aquifers that are draining into the mine, being all those south and east of the town, have been left without a water supply. Perhaps, in another hundred years or so, when the water level in the "mine" comes up to the level of what was the local water table, those wells may produce water again, if they are replenishable and the flow characteristics of the aquifers haven't been irreversibly damaged. The periodic tremors in the area since the mine closure are a sign, unfortunately, that some such damage may be occurring as the aquifers drain, or may have occurred as a result of the tremendous blasts while the mine was in operation.

A full two thirds of the world's people already rely almost exclusively on underground aquifers for their drinking water and over half of global agricultural irrigation uses groundwater. But a third of the world's population lives in areas that are already seriously water-stressed. Where the UN established minimum daily requirement is 10 gallons of water per person these areas have an availability of only 1-3 gallons per day and much of the daily challenge and activity revolves around how to acquire water. Water for sanitation and basic hygiene is one of the greatest challenges in these areas and thousands die every day from infections and water-borne diseases. "One child dies every eight seconds from a waterborne disease; 15 million children a year."[4]

Overall as many as half the world's aquifers are already over-exploited, being drawn upon at a rate greater than they can be or are replenished. Too often a slowly-replenishing aquifer that has served the needs of local farmers and residents for centuries comes under pressure from high volume extraction for commercial use. This, for example, was the case for one aquifer in India where a well-known soft drink company built a plant in the area and drew on the aquifer for the water to make their soft drinks. Hundreds of wells in the area went dry, wells that had been in continuous use for hundreds of years, because the replenishment rate on the aquifer could not keep up with the traditional demand plus the high volume extraction by the software company. Repeated law suits consistently came down on the side of the soft drink company. The rapidly growing global demand for clean bottled water is also putting major pressure on many aquifers, most of them deep, pristine non-replenishable fossil aquifers.

Water in an aquifer, like oil in a reservoir, generally does not exist as a unified body like a vast underground lake. But it can. More commonly, it may saturate a layer of sand underground, like the Alberta tar sands, or it may trickle slowly through cracks and cavities in a rock formation. Look at the face of any rock cliff and you will generally see the telltale vertical dark streaks where water is oozing out of these cracks in the stone. Aquifers may be vast in terms of their overall size, like the Ogallala aquifer - a non-replenishable, fossil aquifer - which covers most of the U.S. midwest. Or they may cover only a few thousand square meters or less. And they may be just a few feet below the surface or a mile or more down.

Our romantic image of a water well is the picturesque round bricked well with the peaked roof and a pull-up rope wound round a hand-cranked pulley. The vast majority of wells, however, and most of those developed over the past half-century, are drilled wells with a pump, sometimes a hand pump, sometimes a windmill, but most often a mechanical pump run by electricity or a gasoline engine. It is these powerful electrical and gasoline-driven pumps that have allowed us to exploit ever deeper aquifers, some over a mile deep, in ever greater volumes (while global population has tripled in the past century global water usage has grown more than six-fold, most of that growth from underground aquifers).

Under China's arid north plain, where much of the country's vast quantities of wheat and other grains are grown, there is a shallow aquifer that has been relied upon for centuries to supply water to mostly hand-dug wells. The replenishment rate is slow but for many centuries the amount of water being used from it was below that recharge rate. Now that aquifer has been seriously over-exploited and has been, effectively, sucked dry. But there is also a deeper aquifer under the north plain that is now being tapped thanks to powerful new mechanical pumps. The problem is this deep reservoir is a non-replenishable aquifer, the fossil water in it having been sequestered there for thousands of years. With more and more wells sunk down to this deep aquifer it too may be sucked dry within a few decades leaving China's breadbasket that feeds much of her 1.6-billion people without a source of much-needed irrigation. China's grain production, in fact, has already fallen while half a billion people have been added to the population from its "peak of 392 million tons in 1998 to an estimated 358 million tons in 2005. For perspective, this drop of 34 million tons exceeds the annual Canadian wheat harvest."[2]

An aquifer, like an oil reservoir, covers a large enough area that multiple wells can draw from it at the same time. In India, for example, the relatively few aquifers in the country are being tapped into by more than 22-million wells. And like oil, each additional well drilled into an aquifer increases the depletion rate and has the potential and often does decrease the water available to the other wells. This becomes seriously apparent when the extraction rate of all the wells exceeds the replenishment rate of the aquifer. This vast mining of aquifers in India, for example, is taking its toll and is "lowering water tables in most of the country. In North Gujarat, the water table is falling by 6 meters (20 feet) per year."[2]

There are literally thousands of legal agreements worldwide covering the right of use of surface water in lakes and rivers. But as much as 97% of the world's liquid freshwater is not in these lakes and rivers but rather in underground aquifers. There are essentially no existing agreements covering the use of groundwater, even though many aquifers cross national borders and their over-exploitation on one side of the border is a strong potential source of conflict and even war. Those few agreements that even mention groundwater cover it as an aside and something to be dealt with in the future. But that future is now, if there is to be a future for the world's aquifers and drinkable water for future human generations.

We are taking our underground water sources for granted and treating them with the same reckless abandon that we treat our lakes, rivers and the oceans. "Toxic chemicals are contaminating groundwater on every inhabited continent, endangering the world's most valuable supplies of freshwater, reports a new study from the Worldwatch Institute, a Washington, DC-based research organization."[3] Just a few U.S. examples, which are similar to examples from other continents, will illustrate the depth and breadth of the problem.

* "Water utilities in the midwestern United States, a region that is highly dependent on groundwater, spend $400 million each year to treat water for just one chemical, the pesticide atrazine. According to the U.S. National Research Council, initial cleanup of contaminated groundwater at some 300,000 sites in the United States could cost up to $1 trillion over the next 30 years."[3]
* "The U.S. Environmental Protection Agency (EPA) estimates that about 100,000 gasoline storage tanks are leaking chemicals into groundwater. In Santa Monica, California, wells supplying half the city's water have been closed because of dangerously high levels of the gasoline additive MTBE."[3]
* "Sixty percent of the most hazardous liquid waste in the United States - 34 billion liters per year of solvents, heavy metals, and radioactive materials - is injected directly into deep groundwater via thousands of "injection wells." Although the EPA requires that these effluents be injected below the deepest source of drinking water, some have entered underground water supplies in Florida, Texas, Ohio, and Oklahoma."[3]

Man is the only species on this planet able to and in the practice of exploiting earth's sequestered resources like oil, natural gas, coal, minerals, and water. Apart from the fact we claim an exclusivity that excludes other species with whom we reluctantly share this planet we also, particularly in this past century, seem to have no sense of responsibility for sharing them with future generations of humans, our own children and grandchildren. The resources they will need for their very survival are being voraciously gobbled up and discarded as an assumed birthright in our greedy demands for support of our increasingly decadent lifestyle. If this robbing from future generations were accidental because we did not understand the long-term implications of over-exploitation it would be bad enough. But it is not accidental. We do understand. Our governments and industry organizations pump out reams of statistics every day detailing our crime. And yet we continue on, as if to say to our grandchildren, "To hell with you. I'm going to have a good time as long as I can and it's your problem to figure out how to survive on what's left when our party is over."


Additional reading material:

1) A Global Water Crisis
2) Aquifer Depletion
3) The Hidden Freshwater Crisis
4) UN Highlights World Water Crisis
5) The Hidden Freshwater Crisis

1 comment:

Ayesha said...

Leaders who adopted the Millennium Development Goals in 2000 envisioned halving the proportion of people living without access to basic sanitation by the year 2015 – but we are nowhere near on pace to achieve that goal. Experts predict that by 2015, 2.1 billion people will still lack basic sanitation. At the present rate, sub-Saharan Africa will not reach the target until 2076.

If we take up the challenge, the positive impact will reverberate far beyond better access to clean water. Every dollar invested in water and sanitation yields an estimated seven dollars worth of productive activity. And that comes on top of the immeasurable gains in cutting poverty, improving health and raising living standards.
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