Our Water Problems Are a Crisis of Management

By Frank R. Rijsberman, Boston Review. Posted January 21, 2009.

When we think about water scarcity, then, we should not be focusing on an absolute shortfall between the total needs of the earth's population and the available supply, but on where the usable water is and what it costs to bring enough clean water to where people are.

That means not only ensuring the accessibility of safe drinking water, but also the availability of enough water for growing food. The former alone is no trivial undertaking. More than a billion people in developing countries invest a significant share of their time and resources in securing drinking water. Available water supplies are so limited in quantity and poor in quality that, combined with poor sanitation and personal hygiene, they are associated with ill health. Diarrheal diseases, generally caused by drinking or handling biologically unsafe water -- water that has been in contact with human or animal feces -- account for an estimated 20 percent of deaths among children under age five.

In the 1980s the United Nations led a massive effort to bring safe water to all people. Aid agencies and UN bodies increased their water budgets significantly, and water was provided to a large number of previously underserved populations. Yet at the end of the "Water Decade," more than a billion people were left without access to safe and affordable drinking water and more than two billion still lacked safe sanitation. In 2000 the world's leaders adopted the Millennium Development Goals, which included a commitment to halve the number of people without access to safe and affordable drinking water by 2015. Two years later they added a target to halve the number of people without access to safe and affordable sanitation. Development organizations are renewing their efforts to reach these goals and have doubled their aid budgets for water supply and sanitation projects to about $6 billion per year. In Asia the targets are likely to be met. Unfortunately, in Africa, where the proportion of the underserved is highest, the development partners are not making great strides.

Safe drinking water in sufficient quantity, however, is not the whole story. Even the most water-scarce parts of the world -- Egypt, for example -- have renewable water resources on the order of 1000-1500 liters per inhabitant per day. The United Nations recommends access to at least twenty liters of safe water per person per day as the minimum for a healthy life. When they have access to affordable water conveniently piped into their homes, people tend to use a great deal more: 200 to 400 liters per person per day, depending on whether they water their lawns or use dishwashers and similar water-guzzling conveniences. But even at that higher level of consumption there is no real scarcity of drinking water.

However, water for drinking, cooking, bathing, and all other domestic needs is only a small fraction of the requisite supply. A much larger amount is needed to grow our food as well as the fibers, such as cotton, in our clothes. On average, growing a single calorie of food demands a liter of water. Plants need water for evapotranspiration, the process by which water evaporates from soil and leaves and transpirates from plants through the stomata, thereby transferring water from Earth's surface into the atmosphere. A healthy diet of 3000 calories requires at least 3000 liters of water to produce; a vegetarian diet requires the least amount of water, while a Western, meat-based diet rich in corn-fed beef can require as much as 15,000 liters of water per person per day. Roughly seventy times as much water is needed to grow the food that people eat as to serve domestic purposes.

Therefore, to understand the water crisis we need to distinguish two fundamentally different problems, which will require different solutions. The first, the drinking water problem, is about access to affordable water services: here we face a service crisis. The second is about the lack of the vastly greater water resources needed to grow food and maintain ecosystem services: here we face a problem of water scarcity, a resource crisis.

The most widely used indicator of water scarcity, the Falkenmark Water Stress Index (after the Swedish hydrologist Malin Falkenmark), defines water stress as less than 1700 cubic meters of renewable water resources in a country per person per annum. Countries with less than one thousand cubic meters such as Algeria, Israel, or Egypt, are said to be severely water-scarce. So when countries are water-scarce in terms of the Falkenmark indicator it does not mean they do not have enough water to drink, but rather that they do not have enough water to grow their own food.

Yet the Falkenmark indicator is a limited measure of whether a country has the water it needs, because it only counts the annual national availability of what is traditionally defined as "renewable" water resources. Rainfall that runs off into streams and rivers, plus the water that recharges the groundwater (and often reenters the streams and rivers later), is defined as renewable. But this water accounts for only about 40 percent of total rainfall. The other 60 percent -- the neglected part -- becomes soil moisture and from there evaporates back into the atmosphere as water vapor or is taken up by the roots of plants and eventually transpirated by the plants' stomata.

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Frank R. Rijsberman is Program Director at Google.org, the philanthropic arm of Google Inc. He was previously Director General of the International Water Management Institute.

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