5 June 2003 Over-exploited aquifiers, falling water tables and seawater contamination are threatening the world's natural underground reservoirs upon which 2 billion people depend for drinking water and irrigation, according to a new United Nations report issued today to mark World Environment Day.
In a “wake up call” to conserve this “hidden natural resource,” the report by the UN Environment Programme (UNEP) urges action to better manage the globe's groundwaters as growing and thirsty cities, industries and agriculture take their toll.
Entitled “Groundwater and its Susceptibility to Degradation: A global assessment of the problem and options for management,” the report concedes, however, that many potential remedies are politically and socially difficult unless long-term goals are adopted. It urges water agencies and government water departments to manage groundwaters in tandem with rivers, lakes and reservoirs in an Integrated Water Management approach.
"Some 2 billion people and as much as 40 per cent of agriculture is at least partly reliant on these hidden stores,” UNEP Executive Director Klaus Toepfer, said in Beirut, chosen as focal point for this year’s observance. “Groundwater also supplements river flows, springs and wetlands vital for rural and urban communities and wildlife. Indeed, most of the world's liquid freshwaters are found not in rivers and lakes, but below ground.”
The report cites numerous cases from across the world to highlight the global threat. In the United States, 400 million cubic metres of groundwater in Arizona are being removed annually, about double the amount being replaced by recharge from rainfall.
In Mexico, the number of aquifers considered over-exploited jumped to nearly 130 by the 1990s, up from 32 in 1975. Impacts include contamination by salt as seawater seeps in to replace the freshwater loss and contamination from the surface caused by pumping.
In Spain, more than half the nearly 100 aquifers are over-exploited. In the Segura River Basin the ratio of groundwater storage depletion to available renewable water resources increased from less than 20 per cent in the mid-1980s to 130 per cent by 1995.
Ironically, some cities in very dry and arid regions like the Arabian Gulf are suffering a form of flooding, known as waterlogging, because of a heavy dependence on desalinated water from the coast which is leaking and becoming trapped in the ground.
The UN's Millennium Development Goals, aimed at halving world poverty by 2015, and the water component of the World Summit on Sustainable Development's (WSSD) Plan of Implementation will be almost impossible to achieve without improvements in water efficiency in agriculture, industry and households, which should in turn conserve freshwaters above and below ground, the report says.