Irrational Use

How much remains?

The evidence to date shows that only a fraction of the aquifer’s reserves has been tapped so far. Massive volumes still potentially remain available for use.

However, based on existing data, future projections for the entire aquifer indicate that total annual groundwater abstraction by people will more than double in a 50 to 100 year period, exceeding five billion cu m per year.

The question now becomes: can the NSAS reserves meet projected future demand? And for how long? If the reserves are managed wisely by all, could they be sufficient for many years of planned abstraction and ‘mining’?

Unfortunately, the answer, far from being crystal clear, is a maybe. One expert says that, at current rates of consumption, reserves could be diminished in as short a time period as 100 to 500 years. The questions above, however, are immediately met with numerous other questions for which information is often lacking or completely missing.

For example, although massive volumes of groundwater do exist, little is known about how the water is distributed throughout the NSAS both vertically and laterally. While at one location water may be somewhere below the surface, the technological capacity to abstract it may be too low and the economic costs may be too high, thereby hindering mining.

Another question relates to over-abstraction. If water is abstracted from the aquifer that will never, or marginally, be recharged or renewed, at what point can one say that abstraction is ‘too much’. In such a situation, it becomes difficult to define how the groundwater should be ‘rationally’ used.