LONDON: Every time there is a drought, water companies can be found dusting off their plans for new reservoirs. After another dry winter in the UK, 2006 is unlikely to be an exception.

Thames Water is preparing plans for the largest man-made structure in Britain a GBP700m reservoir covering 10 square kilometres, with banks rising as high as a church tower above the flat farmland near Abingdon in Oxfordshire, southern England.

The scheme, designed to store water from the Thames in winter and release it downstream in summer, was due to be unveiled next week. Thames Water had booked the local village hall, but then cancelled. The company denies the story, but many believe that the delay is because Thames Water has been put up for sale by its German owners.

Even so, it has pencilled in a public inquiry for 2008 and, if it gets its way, the Vale of the White Horse will be under water by 2020. The alternative could be standpipes in the capital, say the company's engineers.

But few of those engineers will be aware that 30 years ago, before Thames Water was privatized, an economic study by their public sector predecessors concluded that saving water by plugging leaks in water mains and installing new valves for every toilet cistern in London would be cheaper and just as effective.

Britain is a modest user of water, consuming a sixth as much per head as Egypt, for instance. This is mainly because moderate temperatures, reasonable rainfall and cloudy skies ensure that British crops mostly grow without artificial irrigation.

But water engineers in the UK share with their colleagues the world over an obsession with dams and pipes and concrete. They want to supply ever more water, and are deaf to calls for investment in demand management.

And, as I have discovered in a five-year investigation of the world's water, this supply-side fixation is creating a global hydrological crisis that threatens the survival of some of the world's largest rivers.

The world atlas no longer tells the truth. Today, dozens of the greatest rivers are dry long before they reach the sea. They include the Nile in Egypt, the Yellow River in China, the Indus in Pakistan, the Rio Grande and Colorado in the United States, the ancient Oxus that once fed the Aral Sea in Central Asia, the Murray in Australia, and the Jordan, which is emptied before it can even reach the country that bears its name.

The biggest demand on the world's water is irrigated farming, which takes two-thirds of all the water abstracted from rivers and underground reserves. This is largely due to the green revolution.

The "high-yielding" plant varieties that have kept the world fed as populations have doubled over the last 30 years turn out to be high-yielding only when measured against land area. Measured against water use, they are generally worse than the crops they replaced. They produce less crop per drop.

Binding constraint

As a result, the world grows twice as much food as it did a generation ago, but abstracts three times as much water to do it. The UN Food and Agriculture Organization said that on at least a third of the world's fields today, "water rather than land is the binding constraint" on production.

This profligacy is present in every supermarket trolley. The amount of water needed to grow our everyday food is staggering.

To grow a kilo of rice takes between 2,000 and 5,000 litres of water more than many households use in a week. It takes 20,000 litres to fill a kilo jar of coffee, up to 4,000 litres to grow the fodder that will deliver a litre of cow's milk, and up to 11,000 litres to make a quarter-pound hamburger.

In such ways, I reckon I indirectly consume a hundred times my own weight in water every day. US environmentalist and agriculturalist Lester Brown talks of a "food bubble" a world awash with food grown using water that will never be replaced. One day, he said, the bubble will burst. And everywhere I went, I saw why.

I stood on the banks of the Rio Grande at Presidio, on the US-Mexico border, with Terry Bishop, bankrupt despite owning a large chunk of prime Texas farmland.

His problem is that thanks largely to over-abstraction by upstream irrigators his legal entitlement to the river's water is useless. There is no water in the river. In fact, the mighty Rio Grande is now two rivers.

The main US arm, rushing out of the Rockies, gives out just past El Paso, 1,000 kilometres from the Gulf of Mexico. Its bed is then dry for 300 kilometres until, just past Presidio, an old tributary, the Rio Conchos, brings relief from Mexico.

In much of India, the rivers have long-since dried up, and the only water is underground.

In the last decade, more than 20 million farmers have bought drills and cheap Yamaha pumps to bring water to the surface and irrigate their crops. As a result, water tables that were until recently only a few metres from the surface are now hundreds of metres down.

The pumping bonanza is "a colossal anarchy, a one-way trip to disaster," said Tushaar Shah, of the International Water Management Institute, whose HQ is in Gujarat.

He reckons farmers are taking from underground 100 cubic kilometres of water more every year than the rains replace. India's green revolution is living on borrowed water and borrowed time.

Emptying the rivers brings ecological and social chaos in its wake. In northern Nigeria, the Hadejia wetland on the edge of the Sahara once provided fish and pastures and free irrigation water for a million people.

But it is being dried up by inefficient and wasteful upstream irrigation schemes cruelly advertised by the government as "greening the desert." Now cattle herders and farmers fight for the last water. Every year now, there are dead bodies strewn across the wetland.

The death of the Aral Sea, as Uzbek cotton farmers plunder the rivers that once filled it, is a well-known ecological disaster.

But I discovered that it is also a human disaster. The huge state cotton farms bring little wealth now, while the water running to waste from leaking canals and waterlogged fields is poisoning huge swaths of the country with salt.

The stuff is everywhere in drinking water, in soils, in the air during the huge dust storms that blow off the dried up sea, and ultimately in the bodies of the people.

Oral Ataniyazova, a local doctor and health campaigner, took me to hospitals in Karakalpakstan, the worst-hit area, where more than 90 per cent of the population have anaemia, deaths in childbirth are endemic, and cancer rates are among the highest in the world all because of the salt. This forgotten corner of the world is committing ecological suicide.

In my travels, I found massive waste and misuse and misappropriation of water, but I also found huge potential to manage things better.

I visited inspiring villages across India and China where they are reviving ancient methods of capturing the rain as it falls. I met farmers who use perforated bicycle inner tubes as a cheap method of irrigating their crops from meagre water supplies.

And I went to communities in Syria that still rely on thousand-year-old tunnels, known as qanats, that deliver underground water by gravity. I met engineers who want to tear down the dams and give the water back to wetlands and fisheries. And I met citizens demanding a "new water ethic," based on ecology and sustainability and sharing.

I took to using the phrase wherever I went, and it seemed to strike a common chord from Spain to India and China to the United States. Maybe it is time to hear it in Britain, too. We might start with the Vale of the White Horse.

(China Daily 03/18/2006 page9)