A drop-sized way to bring clean water to a thirsty world

Dripping taps in rich countries lose more clean water than is available to more than 1 billion people in the developing world. As you read this, close to half of all people living in poor countries are suffering from health problems that are related to dirty water and poor sanitation. Some 1.8 million children die each year because of diarrhea – a death toll six times higher than that of armed conflicts.

At the turn of the millennium, the World Commission on Water deplored the "gloomy arithmetic of water," and warned that half the world's population would live under conditions of severe water stress by 2025. A seemingly obvious response to shrinking or unpredictable rainfall is to store more water. To counter the global water crisis, the World Bank argues that governments need to build more large dams for reservoirs, in spite of the serious social and environmental impacts that these projects often have.

In a major report on water published Thursday, the UN Development Program (UNDP) takes a radically different approach. The Program's 2006 Human Development Report rejects the gloomy arithmetic. It argues that the poor's lack of water is caused by their lack of political power, rather than by the limits of nature. "The scarcity at the heart of the global water crisis," the UNDP maintains, "is rooted in power, poverty, and equality, not in physical availability."

More investment in water supply is urgently needed. Yet storing water in large, centralized reservoirs concentrates political power. The benefits of big, capital- intensive water investments tend to be captured by the rich and powerful members of society. "The danger is that the claims of the politically and commercially powerful will take precedence over the claims of the poor and marginalized," the Human Development Report warns.

The UNDP's new report joins a growing chorus of voices that argue for a "soft path" to water-sector development. Decentralized, small-scale solutions and efficiency improvements are more likely to reach the poor than centralized reservoirs and canals. "For much of the past hundred years water shortages in agriculture have been countered by dams and large-scale irrigation works," the UNDP says. "In the years ahead the focus will shift decisively to demand management. Getting more crop per drop, rather than more water to the fields, is becoming the central concern...."

According to the UN Millennium Project, the more than 500 million small farming families are the world's "epicentre of extreme poverty." Most of these poor farmers work marginal, rain-fed lands. They are far more likely to benefit from modest investments in decentralized water storage and supply than from billions of dollars sunk into more large dams and canals in fertile river valleys.

A soft path to water supply will rely both on new technologies and traditional methods of storing water. For centuries, Indian farmers have built small dams to store water and recharge groundwater aquifers locally. The Human Development Report estimates that with an initial investment of $7 billion, extending such structures all across India's rainfed farming areas could raise the value of the country's monsoon crop from $36 billion to $180 billion a year.

Another soft tool that can overcome water scarcity at very low cost is drip irrigation. Drip irrigation brings water to plants' roots rather than the furrows, cuts water use by 30-60 percent, and boosts yields by up to 50 percent. International Development Enterprises, a research and development group based in Colorado, has devised a system of drip irrigation that costs a mere $3 for a small plot.

The soft path – exemplified by small dams and drip-irrigation systems – supplies water without destroying rivers or exhausting groundwater supplies. It also creates jobs and gives the poor the means to buy the food they produce. The soft path proposed by the UNDP can break the vicious cycle where poor people lack access to both water and power.

• Peter Bosshard is the policy director of International Rivers Network, an environmental and human rights group based in Berkeley, Calif.