Polly Ghazi describes the potential for using water more efficiently to meet looming shortages

Much of the water we use is wasted, creating the potential for vast savings in precious supplies through conservation. Agriculture, for example, accounts for 70 per cent of all water use, yet 20 to 30 per cent of supplies used to irrigate fields trickle away or evaporate. Industry soaks up 54 per cent of supplies in Europe, where water efficiency is generally low on the list of corporate priorities. And in many countries at least 30 per cent of domestic water supplies leak away.

Conservation technologies and strategies for reducing water demand were high on the agenda at the 3rd World Water Forum in March 2003. Governments have begun to shift away from building large-scale, expensive and often unpopular dams and reservoirs, recognizing that protecting and re-using water can be cheaper and more sustainable than endlessly seeking out new supplies. As Peter Gleick, Director of the Pacific Institute for Studies in Development, Environment and Security in Oakland, California puts it: ‘Whichever country you look at, improving water efficiency is quite simply the cheapest and most efficient means of improving supply.’ He and other conservation-minded water specialists argue for a combination of efficiency technologies, reduced water subsidies, public information campaigns and better targeted aid programmes.

Effective technologies already exist, for example, to minimize the wastage of water used for crops, industrial production, drinking, bathing and lavatory flushing. For farmers, the biggest water users, these include levelling land to minimize runoff, drip irrigation which virtually eliminates waste by delivering water directly to plants’ roots, and low-pressure sprinklers which avoid overwatering. In India, Israel, Jordan, Spain and California, drip irrigation has slashed water use by 30 to 70 per cent while increasing crop yields by 20 to 90 per cent. Early versions of these technologies were expensive, but poor farmers in developing countries are now reaping the benefits of newly designed low-cost drip and sprinkler systems. Villagers in the northern Himalayas, for example, use a $5 bucket sprinkler kit to water vegetable plots more efficiently. And in Bangladesh, rice paddies that previously lay fallow during dry months have been transformed into year-round productive land by the use of groundwater-drawing foot-operated treadle pumps. So far 1.2 million of the $35 pumps have been sold, increasing farmers’ average incomes by up to 30 per cent a year. Many countries are also using simple technologies, such as harvesting rain to conserve drinking water. In Andhra Pradesh, the development charity WaterAid is helping local communities collect rain and channel wastewater back into the ground to recharge supplies. ‘For a few dollars per person you can make a huge difference to the lives of communities and whole regions,’ says Simon Trace, head of its international operations. But he warns that if projects are to be sustainable in the long term, communities must be able to operate the equipment and afford the running costs when aid agencies leave.

Tiered pricing
Other nations are introducing tiered pricing systems, backed by public information campaigns, to discourage overuse by businesses and households. In South Africa, 23 million citizens now receive 6,000 litres of free water a month and pay an increasing fee for whatever extra they use: household water use has dropped substantially in several cities as families strive to stay within the 6,000 litre limit. The city government of Mexico City saved enough water to supply a quarter of a million new residents by replacing 350,000 old lavatories with low-flush ones.
Governments have begun to shift away from building large-scale, expensive and often unpopular dams and reservoirs
In industrialized countries – where households consume vast quantities of water in washing, lavatory flushing and gardening – a combination of public awareness campaigns and tighter regulations governing water-using appliances is slowly reducing wastage. A low-flow lavatory installation programme introduced in the 1990s in New York City reduced water use per building by 29 per cent a year. Free low-flow showerheads followed and water use per person fell from 738 to 640 litres a day between 1991 and 1999. Similar programmes in Boston produced a 25 per cent fall in demand. Under federal law, all new lavatories sold in the United States are now low-flow. Water use by industry is also dropping, due partly to new, more efficient manufacturing technologies and partly to replacing water-intensive metals such as steel with alternatives such as aluminium. Industrial water use has dropped by a fifth in the United States since 1980, while in Japan industrial water efficiency quadrupled between 1965 and 1989. Recycling wastewater is also increasing in industrialized countries. Treated wastewater already provides 30 per cent of farm water supply in Israel – and may reach four fifths by 2025 – and is increasingly used to grow fruit and vegetables in California. Exponents of integrated water management such as Peter Gleick argue that central and local government must educate consumers in the awareness of water conservation, price water to penalize excessive users and reward conservers, shift taxes from labour to resource conservation and even encourage people away from a meat-rich, water-intensive diet.

In the developing world, much of the focus will remain on agriculture. At present, sprinklers service only 10 to 15 per cent of the world’s irrigated fields; drip systems just 1 per cent. Spreading such technologies could cut farm water demand by up to 50 per cent and reduce poverty and hunger. ’the need to increase aid effectiveness to increase access to water cannot be understated,’ Dr. Mahmoud Abu-Zeid, President of the World Water Council and Egypt’s Minister of Water Resources and Irrigation, told an international meeting of water experts in Canada last summer. He urged donors to provide simple, low-cost irrigation and water storage technologies across Africa. All in all, conserving water must play an important part in the world’s efforts to reach its goal of halving by 2015 the proportion of people without ready access to drinking water and sanitation

Polly Ghazi is a Senior Correspondent of Green Futures magazine.

PHOTOGRAPH: C Chamorman/UNEP/Topham

This issue:
Contents | Editorial K. Toepfer | World Environment Day | Water is life | The water century | Taking it at the flood | Renewing the commitment | Waterless cities | Keeping pollution at bay | People | At a glance | Changing agenda | Nor any drop to drink | Bridging troubled waters | Books & products | Getting there | Sinking fast | Waste not | Water – the poor’s priority | Atomic power

Complementary articles in other issues:
Issue on Water, 1996
Issue on Freshwater, 1998

AAAS Atlas of Population and Environment:
Freshwater wetlands
Mangroves and estuaries