Water balance of global aquifers revealed by groundwater footprint (Abstract)

Groundwater is a life-sustaining resource that supplies water to billions of people, plays a central part in irrigated agriculture and influences the health of many ecosystems

Most assessments of global water resources have focused on surface water,, but unsustainable depletion of groundwater has recently been documented on both regional and global scales.

It remains unclear how the rate of global groundwater depletion compares to the rate of natural renewal and the supply needed to support ecosystems. Here we define the groundwater footprint (the area required to sustain groundwater use and groundwater-dependent ecosystem services) and show that humans are overexploiting groundwater in many large aquifers that are critical to agriculture, especially in Asia and North America. We estimate that the size of the global groundwater footprint is currently about 3.5 times the actual area of aquifers and that about 1.7 billion people live in areas where groundwater resources and/or groundwater-dependent ecosystems are under threat. That said, 80 per cent of aquifers have a groundwater footprint that is less than their area, meaning that the net global value is driven by a few heavily overexploited aquifers. The groundwater footprint is the first tool suitable for consistently evaluating the use, renewal and ecosystem requirements of groundwater at an aquifer scale.

Water was one of the building blocks when earth itself was formed, and it is a most wondrous substance. Its presence makes life possible, as there are very few other compounds that have all the properties of water. It is an almost universal solvent, it can exist simultaneously in three different forms, as a gas (water vapor), liquid, and solid (ice), and it has a most peculiar property - water is most dense while it is liquid, at a temperature of approximately 38 degrees Fahrenheit, or about 4 degrees Celsius. As it grows either colder or warmer, the volume of water expands. As it approaches the point where water becomes ice, the molecules splay out at a wider angle, and the solid form of water is LESS dense than the liquid in which it floats. This means the water immediately in the vicinity of ice is more buoyant than slightly warmer water, which sinks to the bottom of whatever container the ice and water stand together. Thus, about a thousand feet down or so, in any body of water, the temperature is a steady 38 degrees F.

Water is just about unique in this respect, as every other liquid element or compound grows progressively more dense as it gets colder. An analog of water, H2O, would be Ammonia, NH3, or Hydrogen Disulfide, H2S. Both of these normally gaseous compounds, when cooled sufficiently, become a liquid (at a much lower temperature than water), but further, when either turns solid, they do not float on the liquid form, but sink to the bottom of whatever vessel in which they are contained.

Whole disciplines of science and engineering are devoted to both the physical and chemical characteristics of water. By taking advantage of much of what we already know, it is possible to apply that knowledge to assure we shall never run out of fresh, contaminant-free water.

We know that water cn be separated from its contaminants by distillation and condensation, on a small scale. Because of cost of providing the heat energy necessary to make this process work, this process is not widely used in high volume.

But by using heat generated by atomic fission, the cost of supplying the heat necessary goes way down, and pure water by distillation becomes relatively cheap. In fact, this is the process used on the US Navy nuclear-powered fleet, so they are continuously producing safe potable water from sea water all the while they are at sea, from the excess heat produced by the atomic piles.

Now, if on the west coast of Africa, there were set up a number of such atomic piles, whose primary purpose was to take up sea water from the East Atlantic, heat it up to vaporization, condense and cool the vapor, and pipe this water over the Atlas Mountains to the western reaches of the Sahara, irrigating those arid lands, we could create a new breadbasket for the world. Over time, the flow of the water from the western Sahara would eventually reach Egypt, reversing the effects of a huge desert and allowing a new rain forest and grain belt to bloom.

A second product of this enterprise would be a huge amount of concentrated brine, or even a dried salt deposit. The major constituent of this brine would be sodium chloride, common table salt, but to a lesser degree there would be significant amounts of every other element that is now dissolved in sea water, including ALL of the metallic elements, and considerable amounts of halides (chlorides, fluorides, bromides and iodides), combined with potassium, calcium, magnesium, and even alumninum. There would even be a significant quantity of iron, nickel, copper, lead, gold and silver, providing a relatively concentrated ore for the extraction of all these elements.

We have not even scratched the potential for recovery of mineral wealth in this world.

I spent a bit of time informally studying groundwater hydrology in the past. I learned that many groundwater sources, like the Oglalla Aquifer, can be recharged with some determination and engineering.

Seems I read recently of a plan to divert spring floodwaters from the Mississippi and tributaries for just such a purpose. The Snake River Plain Aquifer in Idaho supplies lots of water for growing those famous Idaho Russets and other crops (and cooling lots of nuclear reactors at the Idaho Engineering Laboratory.)

While it naturally recharges to some extent from the river itself through porous lava rock, there was once a plan to recharge it during spring high water via drillholes at the north end. I don't know if it's still being considered.

Water balance of global aquifers revealed by groundwater footprint (Abstract)

I have been familiar with every word in this article abstract since I was a new teenager.
But now, when I see the mindless liberal (pun intended) use of words most appropriate in grant proposals, I tune out.

The hydrologic cycle has existed since before industrial revolution, before SUVs and even before man existed.

Scareology is simply the abuse and misuse by the ignorant of science 101 simple words not in common use; simply to wow and impress the rubes. A Democratic party affliction.

Simply another attempt for the wannabe scientists to sway the ignorant into political dependence. I aint buyin it.

We’d also stop wasting water if we stopped putting water into corn to burn for fuel - food that isn’t used for food and forces more irrigation (which loses a lot to evaporation) to grow more real food for consumption.

It is not just wasting corn... it is also wasting energy to make ethanol from corn.

UC scientist says ethanol uses more energy than it makes...

"But in a recent issue of the journal Critical Reviews in Plant Sciences, UC Berkeley geoengineering professor Tad Patzek argued that up to six times more energy is used to make ethanol than the finished fuel actually contains."

The Ethanol Fallacy - an Op-Ed in Popular Mechanics.

.. for example...

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