Groundwater systems

Groundwater is a vulnerable resource. As schemes are developed to pump out huge quantities of water, and with the advent of particularly persistent contaminants, the resource needs to be protected and managed (see Table 2.1). Despite groundwater’s pivotal role in sustaining ecosystems and providing water supply, the resource is still poorly understood, and hence poorly managed, in many parts of the world. When things go wrong, the damage can be lasting or even permanent. For example, over-pumping and continuous long-term contamination by urban effluents and agricultural practices in the Gaza Strip has led to some groundwater becoming unfit for drinking or agricultural use. Even if pumping and contamination stopped today, it would take hundreds of years for the contaminants and intruding saline water to be flushed out of the groundwater system. Some groundwater resources were accumulated aeons ago and are no longer replenished (e.g. many of the sandstone aquifers of North Africa), thus using them is similar to mining non-renewable minerals.