As demand for fresh water outstrips supply across much of the planet, ideas for how to conserve the precious resource are taxing the brains of planners and inventors alike, yielding ideas from the spectacular to the simple.

While building an artificial mountain chain to encourage rain, towing icebergs or building building vast engineering projects to pipe water from tropical wetlands to dry areas are at the more drastic and surreal end of the scale, huge savings can be made with more down-to-Earth methods.

In Australia, the driest inhabited continent on earth, citizens are faced daily with a simple water-saving choice in their homes, offices and pubs -- press one button for a full toilet flush or the other for a half-flush.

If everybody does the decent thing and uses only half the water in the cistern whenever possible the saving may make the difference between being able to water your garden in the dry season and facing a hosepipe ban.

The system is simple but effective, and the government is searching for similar innovations.

It announced last week that 1,750 community groups would share 61 million dollars (45 million US) in funding to undertake water saving projects across the country.

The projects are expected to save around 18 billion litres (four billion imperial gallons) of water a year -- "the equivalent of 18,000 Olympic swimming pools", according to Environment Minister Ian Campbell.

In a country surrounded by seawater, the large cities of Sydney and Perth have seriously considered desalination plants to convert saltwater into fresh drinking water, but critics say the energy used in the process negates any environmental benefits.

The tiny desert state of Kuwait, with a population of three million, has little choice. It gets more than 90 percent of its water needs of around 1.6 billion liters (350 million imperial gallons) daily from sea water desalination through five giant plants.

The plants employ highly-advanced technology, including reverse osmosis. They produce more than 1.36 billion liters of fresh water daily, which is mixed with quantities of underground brackish water.

The government spends annually around 400 million dinars (1.37 billion dollars) on water production.

Australians also baulk at the idea of recycling of waste water, finding the notion of drinking water that has been through sewers unpalatable.

Some countries have pressed ahead, however, like Namibia, the driest and most arid nation in Sub-Saharan Africa.

In December 2002, the local authority in the capital, Windhoek, commissioned a modern water reclamation plant on the city's northwestern outskirts where waste water is filtered and purified and blended with potable water.

The plant produces 21 million liters of water per day, or 35 percent of Windhoek's daily water consumption.

Semi-purified water coming from the city's sewerage plant is used to water the city's parks and sports fields.

Another water saving measure undertaken by the Windhoek city authorities is the system of prepaid water points in shantytowns.

About 650 people from rural areas flock to Windhoek every month and erect shacks at the outskirts. The municipality provides them with dry toilets and water taps.

The informal residents have to buy water credit cards and insert the cards at the tap, when fetching water. In this way water is used in a responsible manner.

In neighbouring South Africa's impoverished Eastern Cape province, locals use an innovative way to draw water -- capturing fog on giant nets and then transforming it into potable water after putting it through a sand filter.

The water drawn in the tiny village of Marubeni is used to provide drinking water to a local school and also used to irrigate the school's kitchen garden.

Cornas Nomkopo, the 44-year-old principal of the school for about 500 pupils, says: "Having water in the school is a great change," adding that his charges no longer had to trek miles to fetch water.

But he concedes the output is irregular.

"In summer there is always a lot of fog but in winter it's a lot less," he says.

The tiny desert kingdom of Jordan ranks among the world's 10 poorest in water and is compelled to explore far larger measures.

In July Jordan, in cooperation with neighbours Israel and the Palestinian Authority, launched in Paris a 15-million-dollar feasibility study to build a canal from the Red Sea to the Dead Sea to save the world's lowest sea from vanishing.

Experts have repeatedly warned that the Dead Sea is shrinking fast, and is estimated to have dropped from 392 meters (1,286 feet) below sea level to 416 meters (1,365 feet) in recent years.

The project would involve building power generation and water desalination plants to supply electricity and fresh water to cover the needs of Jordan, Israel and the Palestinian Authority over 50 years.

Meanwhile Jordan has been striving to reduce household water losses in order to save around 100 billion liters by 2050, investing in waste water recycling plants and dams.

In the United States, planners see simple domestic and commercial water conservation techniques through low-flow toilets and showers, better plumbing, reuse of grey water and water-efficient landscaping as key, with reduction in consumption of up to 40 percent.

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