Abstract

PIP: Access to water is essential to social and economic development and the stability of cultures and civilizations throughout the world historically. The UN Commission on Sustainable Development in mid-1993 emphasized the importance of transfer of technology to poor countries for improvement in water quality. Less attention has been given to the issue of water availability. The amount of fresh water is finite. The capacity for storage of water has increased over time, but commodity expansion has not improved. Salinization processes have proven to be too costly in dollars, pollution, and nonrenewable fossil fuels. As population grows, the average amount of fresh water available declines. Improvements can only be made in efficiency of usage or conservation. Per capita use of water doubled to 800 cubic meters per person per year. But global use of water increased by 4 times in 50 years. Only 2.5% of the world's 1.4 billion cubic kilometers of water is fit for drinking, crops, or most industrial uses. In Africa and the Middle East water resources are declining in availability and quality. An important feature of water resources is the extent of replenishment in the hydrologic cycle. Water availability from rain and snow amounts to about 113,000 cubic kilometers yearly, of which 72,000 evaporates. Aquifers, rivers, and oceans are renewed with the remaining 41,000 cu km. About 50% returns to oceans and 1/8 is too far from human habitation for use. Estimates of renewable freshwater average 9-14,000 cu km yearly, and a substantial amount is needed to sustain ecosystems in rivers, wetlands, and coastal waters. Internal resources within each country may amount to only about 20% of potential water resources, due to water storage suitability of the land and the extent and condition of infrastructure.