11:25 a.m., May 13, 2010----Water is life, and it has no substitute in most of its uses.
Water is renewable, thanks to the hydrologic cycle, but it's also finite.
According to Sandra Postel, director of the Global Water Policy Project and Freshwater Fellow at the National Geographic Society, these qualities make water fundamentally different from other commodities.
Postel was the first speaker hosted by the Delaware Environmental Institute (DENIN) in the new DENIN Dialogue Series. She spoke in the University of Delaware's Mitchell Hall on Monday, May 10.
Postel's basic message was that we live in an increasingly water-stressed world as the result of a rapidly increasing global population and decades of practices that threaten the continued adequacy of this finite commodity.
Many of society's needs for water have been met through damming. Since 1950, the number of large dams in the world has grown from 5,000 to 50,000. “That's an average of two per day over half a century,” Postel said, “and these dams have brought about major changes in our hydrologic environment.”
Water is dammed for a variety of purposes, including hydropower, irrigation, flood control, and recreation. “These are all good reasons economically, but we haven't thought much about what this approach does ecologically,” Postel said.
Water in its natural state performs many of the same functions, but we put little value on the services provided through nature's work. Many rivers no longer reach the sea for extended periods of time, and wetlands are disappearing. In California, for example, 90 percent of pre-development wetlands are gone.
But Postel's most chilling cautionary tale came from central Asia, where the Aral Sea, once the fourth-largest inland lake in the world, has shrunk to a small fraction of its original size because the rivers that replenished it were diverted to irrigate cotton crops. The fisheries in the area are gone, and many people have left the area. Those that remain are generally in poor health, suffering from respiratory problems, anemia, and other illnesses.
“What happened to the Aral Sea really shows the connection between the health of a people and the health of the ecosystem they depend on,” Postel said. “This isn't a parable but a real story about the end of doing things according to the mindset of 'water has value only when we take it out of the natural world.'”
Changing the flow of rivers also impacts biodiversity. Postel cited the Missouri River as an example. The river's natural peaks and valleys have flattened significantly, removing the natural cues that prompt certain species to spawn or migrate.
Climate change has recently added a new stress, altering the hydrologic cycle through floods and droughts, glacial melting, river runoff patterns, and fire.
Given these realities, Postel believes that the problem needs to be addressed through a water management approach that integrates the protection of ecosystem health and ecosystem services. “This will maximize the total value of water,” she said, “and unleash the potential of conservation and efficiency to help meet human needs for water without taking any more out of the environment.”
She cited some instances where policies founded on this philosophy are being implemented. In South Africa, for example, water is treated as a public trust, with the highest priority for its use being to meet basic drinking water needs and the basic needs of ecosystems. “This policy reflects a community-based appreciation for what water is doing for society,” Postel said.
Other practices that would contribute to better water management for ecosystem health include raising irrigation efficiency, improving rain-fed farming, shifting crop patterns, and expanding urban farming.
In some cases, companies are taking a harder look at water consumption in product supply chains. Unilever, for example, has reduced factory water use by 63 percent since 1995, with many of its factories currently at zero discharge.
“The average American's water footprint is 1,800 gallons a day,” Postel said. “Less than 10 percent of that comes out of the faucet. Water is embedded in everything we do. It takes 634 gallons of water to produce a hamburger and 2,900 to make a pair of jeans.”
Postel left the audience with her recommendation for a water ethic: Provide all living things with enough water before some get more than enough.
“This is a very simple guiding principle,” she said, “but we haven't been operating that way.”
Article by Diane Kukich
Photos by Evan Krape