|Freshwater Resources in Arid Lands (UNU, 1997, 94 p.)|
|1: Fresh water - A scarce resource in arid lands|
Fresh water is a fundamental resource, integral to all environmental and societal processes. However, fresh water is only a small component of the total water resources. Lakes, rivers, reservoirs, and groundwater aquifers account for less than one-third of all fresh water, with the rest locked in glaciers and permanent snow covers (Raskin et al. 1995). Arid and semi-arid lands are essentially a diverse group of regions with a variety of social, economic, cultural, and environmental problems, the common feature being a shortage of water at certain times. The danger in treating arid lands as a single geographical region is that an experience in a single arid land might be inappropriately applied to another arid land with dissimilar characteristics.
The mobilization of freshwater resources for human use has grown rapidly during the past century. This growth in water use was closely tied to the Industrial Revolution, which ushered in a period of unprecedented growth in population, consumption and resource use. Referring to table 1, total water use since 1900 has increased by a factor of five, owing to increases in both population and use per capita. Since 1950 alone, global population and water use have more than doubled, while economic output has increased by a factor of five.
The myriad natural and human uses of fresh water are linked by the unitary character of the water cycle (Rogers and Lydon 1995). The use and misuse of water in one location can have far-flung effects, altering downstream resources, affecting the reliability of water flows, and degrading water quality and aquatic ecosystems. As the competition for limited resources increases with expanding water use, water quality often deteriorates and ecosystem maintenance is compromised. In the absence of policies to address these tensions, water competition can evolve into discord between groups dependent on the same resources. Inadequate or degraded water is a matter of life and death in developing regions, where perhaps 25,000 people die daily from water-related diseases. Finally, global climate change has the perilous potential to alter precipitation patterns, to increase the incidence and severity of water problems in coastal areas.
Reconciling the objectives of socio-economic development, environmental quality, and ecosystem preservation into a resilient foundation for the future is the essence of the concept of sustainable development. There are three dimensions to sustainable water development: these are (a) meeting human requirements today and in the future, (b) ensuring water security and conflict resolution, and (c) satisfying ecosystem requirements.
Freshwater resources in arid and semi-arid lands have three components: rainfall, surface water, and groundwater. For these variable water supplies, data collection and analysis are important tasks for enhancing water supplies by such means as irrigation, desalination, precipitation enhancement, and water storage.
Furthermore, management of water resources, especially of interstate aquifers, is an essential issue to the people concerned (from decision makers to farmers). This issue may include hydropolitics on international river basins or lakes.