Sandra Postel

The Coming Age of Water Scarcity

She didn’t start out as a guru, but since the publication of her book Last Oasis: Facing Water Scarcity (Norton) in 1992, Sandra Postel has become one. Now director of the Global Water Policy Project in Amherst, Massachusetts, Postel has become one of the world’s leading authorities on how the world uses water, and how it can conserve for the future. “I’ve been involved in water issues since I left graduate school,” Postel says. “I’ve always had this fascination with water and a feeling of connection to it. Maybe it has something to do with growing up near the ocean on the south shore of Long Island, but it’s been my principal passion for a long time now.”

Last Oasis was made into a documentary, narrated by Alfre Woodard, that aired in 1997 on PBS as the last installment of the four-part series Cadillac Desert. Postel is a former vice president for research at the Worldwatch Institute, and has served as a consultant to the World Bank and the United Nations Development Programme. As a visiting professor at many colleges, she has lectured on water quality and international conservation efforts. Knowing what she does about water pollution, does Postel drink straight from the tap? Yes, indeed, she says. “Here in Amherst, I think it’s fine. I know exactly where my water is coming from—a protected swamp.”

Postel is now working on a sequel to Last Oasis that is about the sustainability of irrigated agriculture. “We need to be looking at conservation alternatives that could double water productivity and give us twice as much benefit from each gallon,” she says. Postel believes that saving water, not wasting it, will be the key to maintaining a healthy supply for the world’s growing population in the 21st century.


E: What is the broad outlook for the world’s fresh water supply? It seems to be one of increasing scarcity around the world.

Sandra Postel: The basic problem is that water is a finite resource. It’s renewable, but it’s finite, and so water supplies per person tend to decrease as population increases. We’re at a point now where we’re about to see a big jump in the number of people in the world living in so-called “water-stressed” countries, where the renewable supply per person is below the level considered adequate to meet all food needs, ecological needs, industrial needs, household and drinking water needs. We currently have about 460 million people living in these countries, and that number is going to jump up to about three billion over the next 30 years. It raises tons of issues about water and agriculture, growing enough food, providing for all the material needs that people demand as incomes increase, and providing drinking water. A billion people don’t have clean water, and two billion don’t have adequate sanitation. This is still the cause of 80 percent of the diseases in developing countries.

Is there a basic conflict between water for irrigation and water for drinking in these water-stressed nations?

Irrigation is by far and away the biggest consumer of water—it takes the lion’s share of the water that we’re extracting from rivers, streams, aquifers and lakes. Drinking water is really quite a small share. In water-scarce regions, you do find agriculture and cities now beginning to compete for the same limited supplies. And where that is occurring, generally it’s the farmers who tend to lose water. When you look at Beijing, China for example, you find that farmers on the outskirts of the city who had been relying on the reservoirs for their irrigation water have been cut off. And that’s going to occur in more and more places. There’s an old adage that water flows uphill towards money. Generally, it’s the cities that can afford to pay more for water and that value water more highly.

We’re seeing this in the western U.S., where water is shifting from agriculture to urban areas. We’re seeing it in parts of India, China and Southeast Asia also. So even though cities on a global basis take a relatively small share, and a small total quantity of water, that competition is real. We have two and a half billion people living in cities right now, and that number is projected to increase to five billion by 2025.

Is water becoming a scarce resource internationally?

In my mind, water scarcity is not the primary reason people lack drinking water. The water is available, they just don’t have access to a safe supply. It’s a problem of inadequate government investment, of political will, of making it a priority to meet the basic water needs of the poor. It’s a solvable problem, if we decide to do it.

What are the primary pollutants of drinking water?

It depends on where you’re looking. The primary source of pollutants in a very localized poor region can be the fact that there’s no healthy sanitation services provided. And so you have a whole variety of microbial pollutants that are entering waterways from human and animal waste. In a more industrialized area, it will be chemicals, toxic metals and other industrial sources. We find in many parts of the world now that rivers are becoming so contaminated by industrial chemicals that they’re no longer suitable for human use. And so, not only is water becoming scarcer, but the existing supplies are becoming unusable—certainly for drinking and sometimes even for irrigation.

This is a big problem in rapidly growing parts of Asia, for example, where you find industrialization occurring without a commensurate investment in wastewater treatment. Similarly in cities, you have urban areas growing very rapidly, and the increased discharge of waste water, containing nitrogen, phosphorus and other pollutants. Essentially, nutrients become pollutants when they’re not treated and allowed to collect in waterways, along with the industrial chemicals also coming in. You find in some major cities like Bangkok, Thailand that the rivers are like sewers, because so little treatment is going on. It’s usually the case that 80 to 90 percent of the wastewater being discharged from cities and developing countries is untreated. A much higher level of treatment is occurring in the United States, Japan and Western Europe.

1998 Robert Tobey / Tobey Photo

I imagine that the problem gets even worse as populations increase?

That’s right. It increases as population and industrialization increase. You have more economic activity, more pollution being generated, but not a commensurate investment in wastewater treatment. So the pollution loads on rivers and aquifers increases.

You’ve written that the Colorado River actually doesn’t reach the sea most of the time now, because so much water is pumped out of it for irrigation and other uses. You cite other examples internationally. Is this a growing phenomenon? What would be the negative effects of rivers not reaching their end point like that?

It is a growing phenomenon—a surprising one, too. During the dry season, there are now many major rivers that just don’t make it to their final destination, which is the sea or an inland lake. And that’s a very serious problem. It indicates that water is becoming very scarce—that these rivers are virtually capped out during the dry season. The Colorado isn&#821

7;t reaching the sea not only during the dry season, but all year-round. This year, because of El Nino, there was a lot of snow pack and a lot of rain, so river water will be making it out to the Gulf of California. But in average years, since the completion of Glen Canyon Dam in 1961, there’s been virtually no water reaching the delta and the sea.

Seven U.S. states and Mexico divided up the river in a compact in 1922, but it turned out that more water was promised than the river actually carries in an average year. So it’s a result of the way the treaties were designed, the fact that the environment wasn’t included as a legitimate user of water. That has to be taken into account, otherwise we’re going to have this sort of domino effect of ecological decline happening in river after river.

The Nile has very little freshwater discharging to the Mediterranean now. And look at the Yellow River, which is China’s second largest. The Yellow has been drying up for an average of 70 days a year for the last 12 years or so. And in 1996, it went dry for a third of the year. Last year, it was dry for 226 days, roughly two-thirds of the year, which is a record. The first year they detected a complete drying of the river was in 1972, and it’s been going dry for longer times in recent years.

You’ve got a very important agricultural area near the coast that depends on this water for irrigation, and cities that depend on this water for drinking water supplies. The problem is compounded by drought. The Chinese are aware of this, and they’re trying to deal with it in various ways. They’re talking about a major diversion of water from the Yangtze River, which is much larger than the Yellow River, with about 16 times the volume of water. The Chinese are pursuing two of the biggest water projects in the world right now, this being one of them.

The Three Gorges Dam, on the Yangtze, is a gigantic hydroelectric-generating project. They’re also building one or two other very large dams in China, all very destructive to rivers. They can do this partly because the scientific, ecological and social debate about these projects has been stifled in China.

There is a kind of water war going on in Albuquerque, New Mexico, involving high-tech companies like computer chip maker Intel, which uses millions of gallons of water a day in a very parched region. Intel buys water at reduced rates while consumers are being told to conserve and not wash their cars. Intel is now trying to buy water rights in rural agricultural communities, which has caused an outcry. How do you solve problems like this?

Metropolitan areas need to live within the limits of their water supply, and we have numerous examples in the American southwest where they’re not doing that at all. Cities have to reach out to rural areas to acquire their water supplies, and Los Angeles is the classic example of that. Tucson and Phoenix are in that boat, too. One problem with Albuquerque is that it discovered that it actually had less groundwater than it thought. The city was already overpumping its groundwater at a very rapid rate. Cities that are meeting today’s needs by pumping tomorrow’s water are not in a sustainable situation, and eventually that will come home to roost.

Living within our means can mean conservation, or it can mean recharging groundwater basins if you have the right hydrological conditions. But conservation has not been tapped to anywhere near the degree it could be. Also, it’s generally less expensive than new water supplies. Unfortunately, the policy and pricing incentives haven’t been there—there’s been a reluctance to charge the full price for water for a variety of reasons.

The problem with industry is that municipalities will charge lower prices in order to keep these large customers. If you try to raise the price, sometimes the industry will go out and drill its own groundwater well. And that encourages more overpumping and unsustainable use of groundwater. It’s a problem in areas where there’s no regional management of the municipal water supply. Groundwater is almost a free resource in many areas. And we can’t afford that much longer. In the short run, cities benefit from the increased jobs that industry brings in, but in the long run, they pay for it.

Can you talk about water rights?

In water-scarce parts of the world, there will be a need to shift water out of agriculture into cities and industry. How that shift occurs is important—for food security, and for the stability of rural areas. One of the ways it can occur is through programs in which farmers have clear water rights—and the ability to sell those rights. If the program is set up properly, the farmers can invest in conservation measures, use their water more efficiently, and sell the surplus to cities. The cities benefit, and the farmers do, too, because they’re getting extra income from the sale of the water.

But in order for all of this to work, there has to be clear property rights to water, and in many parts of the world that simply doesn’t exist. In some places water is owned by the state—rights are not given out to private users. In other countries, water is viewed as a gift from God, and it’s not even priced. So there you have difficulty getting incentives to use it efficiently. It’s an unfortunate point that water is underpriced pretty much everywhere.