Mountains are often called nature's water towers. They intercept air circulating around the globe and force it upwards where it condenses into clouds, which provide rain and snow.
Mountains also store water in various ways, including the formation of snow and ice which is later released as melt-off during warmer periods (often those with the lowest rainfall).
It is no surprise then that in semi-arid and arid regions, over 70 to 90 percent of river flows come from mountains. But even in temperate areas, 30 to 60 percent of freshwater can come from highland watersheds. In the Rhine basin, for example, the Alps provide 31 percent of annual flows in summer more than 50 percent even though they make up just 11 percent of the basin's land area.
In fact, all the major rivers in the world from the Rio Grande to the Nile have their headwaters in mountains and one of every two people on the planet depends on mountain water in one way or another: for drinking, as a source of energy or income, for growing food.
A precious, and finite, resource
That water plays a major role in sustaining human life is obvious. Worldwide, freshwater supplies 12 percent of the fish people eat, accounts for some 20 percent of electrical power generation and supports about 40 percent of food-crop production via irrigation.
But the power of mountain rivers isn't always exported to lower elevations. In rural Nepal, for example, there are an estimated 25 000 water wheels and over 900 micro-hydropower turbines a more recent technology that provide a critical source of energy for area residents.
Increasingly, however, it is becoming clear that without more attention to the sustainable management of this finite resource, emerging water supply problems will only worsen with serious consequences for agriculture and food security, especially in the developing world.
Today, around 1.1 billion people worldwide do not benefit from access to safe water supplies. A disproportionate number live in developing countries where water scarcities are so great that the ability to grow food and to build a stable economy have been severely hindered.
The trickle-down effect
Contrary to what one may think, mountains are fragile ecosystems. The vertical nature of a mountain its contours, projections, peaks and plateaus makes its surface unstable. Mountain soils, which form more slowly because of higher altitudes and colder temperatures, are often young, shallow, poorly anchored and susceptible to erosion.
Human activities can tip the delicate balance of mountain ecosystems. Deforestation of high-altitude woodlands, mining, unsustainable agriculture, urban sprawl and global warming are all taking their toll on mountain watersheds and, through impacts that relate to water, on people and ecosystems downstream.
"Whatever happens in upland watersheds has a massive impact on downstream areas," notes an FAO fact sheet on the subject. "Often, the health of an entire watershed depends on preventing environmental degradation in these areas."
Healthy mountain ecosystems help prevent soil erosion, reduce sedimentation in reservoirs and mitigate the risks of mudslides and floods, all problems that can threaten downstream water supplies.
However, mountain populations are amongst the poorest and most disadvantaged in the developing world poverty, isolation, population growth and limited access to land are forcing many upland peoples to adopt farming and survival practices that damage the environment, says FAO.
The challenge then is not only to protect mountain ecosystems, but to involve mountain communities in doing so in ways that are culturally and economically appropriate and strengthen their abilities to earn livelihoods in a sustainable fashion.
As part of its work to strengthen land and water resource management in highland areas, in 2002 FAO launched the initiative, The Next Generation of Watershed Management Programmes.
The Organization, in close collaboration with partners, recently conducted an extensive review of the successes and shortcomings of watershed-based management in forests and mountain areas and will soon issue a set of guidelines for good watershed management as a tool for policy-makers, communities, government agencies and others involved with managing mountain resources.
FAO also chose "Mountains: source of freshwater" as the theme the first-ever International Mountain Day to build awareness of the key role that mountains play in supplying the world with water.
Water is essential to human life, and healthy mountain ecosystems are essential to global water supplies," says Douglas McGuire, head of FAO's Mountain Group. "By taking care of the world's mountains, we help to ensure the long-term survival of all that is connected to them, including ourselves."
Information Officer, FAO
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