Author
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Bouwer, Herman |
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Submitted to: International Seminar on Planetary Emergencies
Publication Type: Proceedings Publication Acceptance Date: 8/24/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Population growth will cause increasing demands for good quality water, increasing sewage flows, and increasing need for irrigation to produce adequate food. Also, there will be more environmental concerns about aquatic life, recreation, riparian habitats, and other surface water benefits. Thus, increased competition for water can be expected. Water resources management increasingly must be integrated or holistic, taking all aspects into account such as supply and demand management, transfers, conservation, quality, pollution, reuse, conflict resolution, public involvement, health, environment, socio-cultural aspects, storage, conjunctive use of surface water and groundwater, sustainability, etc. Since regional climate changes are difficult to predict, water resources management must be flexible to handle changes in water availability and demand. About 98% of the world's liquid fresh water resources occur as groundwater, which must be managed to prevent undesirable depletion and pollution. Groundwater reservoirs are more suitable than dams for long-term storage of water in times of water surplus for use in times of water shortage. Thus, artificial recharge of groundwater and water banking will increase. Planned water reuse also will be needed more and more as it gives compression and greater control of the hydrologic cycle. Use of "virtual" water as imbedded in imported food and electric power may well become an attractive alternative to developing new water resources where water is scarce and expensive. Efforts should be internationally controlled so that food does not become a political weapon. This targets international audiences of policy makers, researchers, and water-related government agencies with ultimate beneficiaries being all water users. Technical Abstract: Most of the world population increase will be in the Third World. Also, more and more rural people will migrate to the cities, creating mega cities with mega water needs, mega sewage flows, and mega problems. Many parts of the world will have severe water shortages, and water management must be increasingly holistic, taking into account all aspects of water development, use, and reuse. Because regional climate changes are difficul to predict, water management must be flexible. Surplus water in wet periods must be stored for use in dry periods. This may require long-term storage (years to decades) that can be done via artificial recharge of groundwater. Planned water reuse will also be needed more and more to compress the hydrologic cycle to a local, controlled scale. A serious threat to groundwater is nonpoint source pollution by agricultural chemicals like nitrate and pesticide residues. In irrigated areas with dry climates, salts can also be a problem. Where sewage effluent is used for irrigation a whole new spectrum of pollutants can enter the groundwater, such as disinfection byproducts, pharmaceutically active chemicals, and humic and fulvic acids which are disinfection byproduct precursors when the groundwater is disinfected again for drinking. In water short areas, importing food and electric power from water rich areas may be better than developing new local water supplies. The water that was then required to produce these commodities is called "virtual" water because it is "virtually" embedded in the imported products. |
