last updated 24th August 05
by 4ecotips.com

Increase cost efficiency of nature's “factories”

By taking advantage of the work that healthy watersheds and freshwater ecosystems perform naturally, cities and rural areas can purify drinking water, alleviate hunger, mitigate flood damages and meet other societal goals at a fraction of the cost of conventional technological alternatives.

This is according to a new Worldwatch study by Sandra Postel, director of the Global Water Policy Project and a Worldwatch Institute senior fellow. But because commercial markets rarely put a price on these “ecosystem services,” and because governments around the world are failing to protect them, they are being lost at a rapid rate, she writes in her report, Liquid Assets: The Critical Need to Safeguard Freshwater Ecosystems.

Global warming is the wild card that could further exacerbate the impacts of human activities on the natural systems that safeguard our water supply—impacts that include falling water tables, shrinking wetlands, vanishing species, and a decrease in both the quality and quantity of available freshwater.

Pollution, population growth, and antiquated policies are contributing to the litany of serious impacts. Water management methods in the twentieth century have attempted to control and manipulate the hydrological cycle to best fit human needs with dams, diversions, levees, and reservoirs.

While these engineering solutions help provide food, water, and electricity for many people, they have also severely disrupted the functioning of aquatic ecosystems.

Some of the impacts mentioned in the report include:

• Dam construction: Over 45,000 large dams now exist, up from 5,000 in 1950. Dams affect over half of the world's major river systems and more than three-quarters of large river systems in the United States, Canada, Europe, and the former Soviet Union. Dams contribute to species and habitat loss, deter fish migration, destroy natural flow patterns, and alter water temperature and nutrient and sediment transport.
  
• Pollution: Increasing amounts of fertilizer, pesticides, heavy metals, and synthetic chemicals are being released into aquatic ecosystems, drastically altering the chemistry of lakes, rivers, and streams. These pollutants lessen the safety of drinking water, harm fish and wildlife, and lead to the spread of oxygen-depleted "dead zones." Use of nitrogen fertilizer, which has been implicated in the spread of these zones, has increased eightfold since 1960.
  
• Greenhouse gas emissions: Climate change linked to the buildup of carbon dioxide and other greenhouse gases in the atmosphere is expected to shift rainfall and runoff patterns, melt glaciers and shrink snowpacks, and increase the number and intensity of floods and droughts. Some of these trends appear to be under way already.