Course Readings

Pimental et al. (1997)
Postel et al. (1996; Abstract Only)

Webliography

Covich et al. 1998. Ecological integrity and western water management: a Colorado perspective
Federal Actions on the Clean Water Act: The Vice President's Memorandum
Global Water Partnership Water Forum
Where You Live

    Humanity is the now one the major driving forces in the Earth's hydrological cycle. Humanity uses "more than half of the freshwater runoff, and, of that, 70% is used in agriculture" (Vitousek et al. 1997). Most of the world's rivers are dammed and the number of dams is increasing (there are 36,000 dams and counting). Only 2% of rivers in the USA run free and many major rivers (Colorado, Nile, and Ganges) are so heavily used that little or no water reaches their deltas and the sea. Major inland water areas (Aral Sea and Lake Chad) have nearly dried up or been greatly reduced to small lakes.

    Freshwater is the world's next gold. Freshwater is only about 2.5% of the total volume of the water on Earth, but just 0.8% is in aquifers, soils, lakes, wetlands, rivers, plants and the atmosphere (Postel et al. 1996). Freshwater sustains ecosystems vital for human welfare, agriculture, industrial production, and human health.

    Postel et al. (1996) estimates the available freshwater resource worldwide to be about 9,830 km³/year. Humanity now uses 25% of all terrestrial evapotranspiration and 54% of all runoff (Postel et al. 1996). If current trends continue, total appropriation of this available amount would be about 2,205 km³/year, or 70% of the total.

    The rates of overdraft of some aquifers (such as the Ogallala in the south central USA) are so large that water has essentially been turned into an non-renewable resource (Pimental et al. 1997). There are other areas of the world where the area of irrigated agriculture is actually declining due to overuse.

    Pimental et al. (1997) say that agriculture uses about 87% of the world's available water, and it receives huge subsidies. In California, farmers pay 0.5 cents per cubic meter of water whereas the public pays 25 cents per cubic meter. Undercharging results in inefficient use of water, waste and the planting of low value crops (e.g. alfalfa in the Colorado Desert).

Cost of water in various places

Place	Average Price   (US cents per m3)
USA	45.12
Norway	34.26
Germany	170.81
Fort Smith, AR	19.52
Pittsburgh	100.00

Source: National Utility Service (1997)
International Water Price Survey

     Postel et al. (1996) urge major investments to be made in improving efficiency of use, recycling, and pollution control; plus changes in agricultural cropping patters and water use, and removing marginal lands from irrigation.

    New dam construction could increase the amount of runoff used by about 10% over the next 30 years, but population growth is expected to increase more than 45% during this period (Postel et al. 1996). Here in southern California, the Metropolitan Water District is constructing the Eastside Reservoir near Hemet, CA at a cost of $2 billion. The dam will be the largest earth and rock filled dam in the country. But Pimental et al. (1997) says, "The era of constructing large dams and conveyance systems to meet water demand in the United States is drawing to a close; the limited water supply and established infrastructure require that demand be managed effectively within the available water supply."

    Pinkham and Chaplin (1996) use an interesting technique they call "scenario building" as a tool to examine future scenarios facing planners of municipal water systems today. They state that "scenarios are a tool for helping us to take a long view in a world of great uncertainty." They try to lay out the uncertainties that face planners for municipal water supplies under these four different policy environments:

   dominant federal role, weak financial environment
   reduced federal role, weak financial environment
   dominant federal role, supportive financial environment
   reduced federal role, supportive financial environment.

Population is the Key

    Demands for water and food are driven by the addition of nearly 93 million persons a year to the Earth (more than the population of Mexico). Add to this the unheard to growth in affluence in East Asia. Population growth is tied to urbanization, ecosystem destruction, food, water, energy, health, public safety and community stability issues. Curbing population growth is the key issue for future environmental and social sustainability (Daily and Ehrlich 1992).

    Countries with per capita water availability of less than 1,700 liters per person per day are classified as "water stressed" nations. Those with per capita availability of less than 1,000 liters per person face water scarcity where water availability hampers economic development and human well being (Engelman and LeRoy 1996). US water availability is 5,100 liters per capita per day (Pimental et al. 1997).

    Various scenarios of population growth into the next century give great concern over water availability for human needs and agriculture. Water shortages threaten to undermine political stability, economic development and health for millions of people. If the highest projections of population growth by the UN are used, by 2050, 65% of the projected world population, 7.7 billion persons, living in 66 nations face either water scarcity or water stress. Under the lowest estimates, 3.5 billion people in 51 countries will be affected. At least 20 nations get more than half of their water from rivers that cross national boundaries (Pimental et al. 1997). The difference between these two figures illustrate clearly how different rates of population growth could affect the water of water supplies around the globe.

    The latest (Feb. 1998) projections from the UN are that world population will stabilize at about 11 billion by 2200.

    In the USA, the net increase of 3 million persons per year is blamed from the loss of million of acres of farmland to urbanization and lack of water. 60% of the US population growth is caused by foreign immigration, a portion that will rise to 90% in coming decades if current immigration policies continue (Pimental 1997).

    In developing nations, the population/water nexus is even more alarming. Time Magazine (24 June 1991, p. 60) referred to the crisis as "the demographic winter". Over the next 20 years, of every 10,000 new births, only 50 will be in the rich countries (Swaminathan 1992). "A poverty curtain divides the world materially and philosophically. One world is literate, the other largely illiterate; one industrial and urban, the other predominately agrarian and rural; one consumption oriented, and the other struggling for survival" (Swaminathan 1992). The rich countries today consume about 20 times more resources per capita than the poor countries. But as economies have strengthened, especially in Southeast Asia, consumption rates of resources are rising dramatically.

    Recently, a group of scientists have banded together to ask world leaders to provide leadership to initiate incentives to reduce family size and conserve natural resources in order to achieve a high standard of living (Pimental and Dodds 1997).

Bibliography

Daily, G. and P. Ehrlich. 1992. Population, sustainablity, Earth's carrying capacity. BioScience 42: 761-771.

Engleman and LeRoy. 1996. Sustaining Water: Population and the Future of Renewable Water Supplies. Population Action International.

EPA. 1994. National water quality inventory, 1992: Report to Congress. Office of Wetlands, Oceans and Watersheds, US EPA, Washington, DC.

Mitsch, W. 1993. Ecological engineering. Environmental Science and Technology 27: 438-445.

Pimental, D. 1997. US food production threatened by rapid population growth! CCN, 2000 P Street, Suite 240, Washington, DC 20038.

Pimentel, D. et al. 1997. Water resources: agriculture, the environment, and society. BioScience 47: 97-106.

Postel et al. 1996. (Abstract Only) Human appropriation of renewable fresh water. Science 271: 785-788.

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