just keep pumping

A lot of the world’s major agricultural regions are irrigated by groundwater rather than surface water.  Even locations with enough rainfall to avoid irrigation under normal conditions are adding capacity to irrigate with groundwater under drought conditions (my home state of Georgia is a prime example).  Well, worrywart scientists have done some large-scale analysis to put numbers on which of 800 aquifers worldwide are being overexplioited for irrigation.  Lots of anecdotal evidence does not make a scientific fact, after all.

It must be an important study, because it was published recently in Nature:

…in most of the world’s major agricultural regions, including the Central Valley in California, the Nile delta region of Egypt, and the Upper Ganges in India and Pakistan, demand exceeds these reservoirs’ capacity for renewal.

…In calculating how much stress each source of groundwater is under, Gleeson and colleagues also looked in detail at the water flows needed to sustain the health of ecosystems such as grasses, trees and streams.

That’s a troubling development, which doesn’t surprise me of course, because of the implications for agriculture when these groundwater sources run out.  And before agricultural collapse, we’ll probably see major impacts to the environment as far as ecosystems drying out and creeks/streams drying up.  We won’t even have anything nice to look at while we die of starvation.

Ok, it’s not quite that dire, of course.  The first step is to identify the problem after all.  But at some point, nations will need to examine the unregulated groundwater extraction for irrigation and ask if the water use is worth the risk.  The ongoing US drought, for example, has many wondering why you would ever grow rice, cotton, or pecans in a place like California or Texas.  In news that should shame us, Saudi Arabia made a push in 2009 to shift its domestic agriculture away from water-intensive wheat and soy beans in order to conserve its limited water supplies.  Of course, non-representative government doesn’t really have to worry about public outcry to get things done (see: China).  But let’s hope that our governments take heed before the tragedy of the groundwater commons plays out on a large scale.

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yes but what will they drink?

Anyone out there ever had unexpected house guests?  You’ve got your plan for the evening, maybe just enough food for yourself or your family, and surprise, there’s an old friend at the door.  You try to play it cool and look like it’s no inconvenience, praying that you have enough in the fridge and maybe an extra bottle of wine or couple of beers to be hospitable.  It’s a tight position.

In the Middle East, Jordan is a relatively responsible water manager.  Limited in water supplies, the country’s population growth has stalled and development has been relatively well planned to balance ecological needs with human needs.  But Jordan has a lot of unstable neighbors, and therefore tons of unexpected, unplanned-for guests in the form of refugees.  Palestinians escaping Israel account for one third of the country’s 6.5 million people, plus they took on influxes of Iraqis in 1990 and 2003 (roughly 450,000 remain), and today, they are the refuge for many Syrians.  In an effort to meet the unexpected extra demand, the country started tapping its main aquifer in the 1980s for the Palestinians, and briefly stopped the extraction for ecological purposes (save the wetlands!) but could not supply the refugees without it.

Now the Azraq aquifer declines approximately 1 m annually, as about 56 million cubic meters are annually withdrawn; the aquifer can only naturally support 20 million cubic meters of annual withdrawal.  Taps in Amman run dry in the summer, and the declining levels are increasing the groundwater’s mixing with a deeper saline reservoir, so that the remaining groundwater is saltier and saltier.  Jordan is trying its best to do the right thing — take care of the refugees, preserve the wetlands, supply everyone with water, and get the withdrawals back in balance with natural recharge.  Jordan already recycles its wastewater for indirect potable reuse, it has plans for desalination, and it’s trying to get local people and neighbors on board with water plans.  So type A.  But it won’t last forever if these refugee surges keep coming…I’m guessing they wish their neighbors would all just get along.