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Distressed aquifers

Mike Woolgar | 06 Jul 2015 | Comments

An article in the FT (paywall) recently highlighted that more than a third of the world’s biggest aquifers, a vital source of fresh water for millions, are “in distress” because human activities are draining them, according to satellite observations. It is undoubtedly true that unconstrained use of aquifers is not sustainable. In many countries there is either no, or very ineffective, regulation of abstraction. This is sometimes based on the assumption, in the absence of good information, of the ability of the aquifer to replenish. Of course the aquifer should really only be exploited such that the inflow to create storage is not exceeded by the rate of abstraction. All too often the supposed regulators know neither how much water is taken nor how much is being replenished: people do not clearly report their abstraction and unless someone is checking flow meters on a regular basis it is all too easy to pump for longer than permitted or to install a more powerful pump. Add to this the high level of variability of rainfall, salinisation and other quality issues and clearly we are at risk of “mining” water rather than managing or husbanding it properly.

One of the world’s largest aquifers in the US – the Ogallala aquifer – has been ruined by lack of control. There are some states in the US where anything below your land belongs to you and may not be regulated. In the case of an expansive water aquifer which others can tap from “next door” there is little incentive to use water sparingly if your neighbours can all take the water at a high rate and deplete what is below your feet; indeed it might make some weird sort of sense to take what you can yourself before someone else profits from it!