ABSTRACT
Of the earth’s 109 cubic kilometers of water, less than 1% comprises fresh water, and of this, three-quarters is frozen in icecaps and one-quarter occurs in aquifers or groundwater. Only 2% occurs on the surface in rivers and lakes, i.e. the volume in fresh water in the ground is about 20 times the volume accessible on the surface. Groundwater is therefore not a small resource and indeed the fact that it is stored for years in aquifers makes the aquifer a huge storage system. The problems arise when we try to abstract groundwater because the aquifers are frequently not very permeable and many boreholes are needed to abstract large volumes from the ground. The long-term effects of abstraction need consideration, as well as the recharge rate.
