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With enough cheap energy, all our water problems evaporate
All problems of water scarcity can be overcome -- as long as energy is in tremendous, cheap supply.
Des Moines sits at the confluence of two rivers, the Des Moines and the Raccoon. And because of a long-running drought, more than half of the state of Iowa is in some state of moderate to extreme drought -- including the watersheds for both of those rivers. The result is that the Raccoon River is barely a neighborhood stream rather than the meaningful river (and major source of drinking water) to which Central Iowans are accustomed.
■ Surface waters supply public drinking water systems in the US with more gallons per day than groundwater wells, by quite a margin. Obviously, though, surface waters are subject to the effects of conditions like drought (and, significantly, runoff pollution).
■ Our politicians love to talk about "infrastructure", and our voters love to applaud it, but water rarely makes anyone's hot list. Roads, bridges, airports, and other related investments in transportation all rank much higher. Yet drinking water ought to be a spectacular stepping-off point for getting the public to think about the water-energy nexus.
■ It is entirely possible to keep almost all of the water we need circulating within a closed loop. The proof can be found aboard the International Space Station, where astronauts drink recycled urine. We shouldn't blanch too much at the idea -- ultimately, all water is recycled; the only thing that changes is how far removed you are from the previous use.
■ What makes old water ready for re-use is treatment, and treatment requires energy. Surprisingly little is needed in the way of chemistry in order to make water safe -- but we do need a great deal of energy. Whether through distillation or aeration, reverse osmosis or ozonation, much of what's actually done to make water safe for consumption involves energy more than just about any other input.
■ Given enough energy, in fact, it is possible to desalinate seawater or collect atmospheric vapor in useable quantities. And, given enough energy, it is possible to move water from any place to any other place (typically by pumping, but even possibly by sea).
■ The crux of the matter is that all problems of water scarcity can be overcome -- as long as energy is in tremendous, cheap supply. Either it can be moved from where it is abundant to where it is scarce, it can be recycled almost indefinitely, or it can be captured from the atmosphere or from the sea and turned into potable form.
■ That should not stop us from implementing as many reasonable measures for conservation as we can find, and it is worth noting that gentle nudges in the direction of high-efficiency appliances and low-flow plumbing devices have contributed to considerable declines in domestic demand. The rule of thumb used to be that indoor household consumption was about 100 gallons per person per day, but that figure has fallen to 82 gallons nationally and less than 75 gallons in some states (including Iowa and a few of our neighbors).
■ Nevertheless, we haven't arrived at that blissful moment of energy superabundance -- at least not yet. So the water sector, while it struggles for the attention and investment it so badly needs in order to face the droughts and other troubles of the present, needs also to press hard for energy innovations, particularly in the field of electrical generation and transmission.
■ There may even come a time someday when energy is so cheap and super-abundant that we could apply it almost recreationally to problems like removing excess nutrients from rivers and streams before they cause algal blooms and dead zones downstream. But in the shorter term, careful use and responsible local management are of the utmost importance.