The Chile Government has announced restrictions on mining company access to groundwater.

The measure, approved last week as part of a wider revision of Chile’s water code, requires all but the smallest mining companies to seek government authorization before using these resources. Water administrators are empowered to refuse permission “if it would compromise the sustainability of the aquifer or the rights of third parties.”

This announcement serves to remind us that many of the world’s aquifers are in overdraft. Solving acute groundwater depletions requires tough science-based water-allocation and difficult water-management decisions by political authorities.  Our “groundwater inheritance” is rapidly dwindling. Our sustainable levels of groundwater use are exceeded in many places in many countries.

With world population increasing at 150 people a minute, and with the uncertainties of climate change impacts, many regions will suffer (some are already suffering) severe social and economic consequences. Groundwater pumping has to be managed to take account of the reality of rates of aquifer recharge.  Managed aquifer recharge (aka) artificial recharge, may be a solution, but it is dependent on there being a source of water to use for recharging aquifers. 

Objective (not over-optimistic) scientific assessment of available volumes of usable water in aquifers and the dependability of potential recharge resources is the first step.  The politics and legal aspects of allocation and management decisions are much more complex; although once the resources are gone then allocation policy may become totally theoretical!

The banking metaphor is a good way to describe the situation.  We are reducing the amount of water stored in our aquifer savings account because we continue to use more water than we have coming into our checking account.  In some places the groundwater savings account has allowed profligate water use for many decades.  Changing weather patterns and ongoing drought are revealing those places where the savings account is almost down to zero at the same time that there is a reduction of surface water availability and/or natural recharge to the aquifers.

Dependable data are a prerequisite to solving water conflicts such as jurisdictional authority, resolving legal issues of water rights from over-appropriated systems and dealing with employment, social issues and consequences of a reduced tax base in areas with predominantly water based economies. With ongoing overdraft of aquifers, the work of hydrologists and geologists is increasingly important to provide elected officials and decision-makers with accurate data and informed opinion and projections about the status of our water resources.