A new United Nations body to help avoid possible "water wars" of the future has been announced here in Japan.
By Tim Hirsch
BBC environment correspondent in Kyoto
The Water Co-operation Facility will be based in Paris at the headquarters of the cultural organisation Unesco, and will mediate in disputes between countries which share a single river basin.
The Ganges-Brahmaputra basin is a potential conflict site
It follows publication of a report identifying 17 basins which have the potential for disputes in the coming decade - for example, where dams and big river diversion schemes are planned which could affect the flow of water across borders.
They include the Ganges-Brahmaputra basin in South Asia; the Salween which straddles China, Burma and Thailand; and the Okavango and Limpopo rivers in southern Africa.
Launching the new facility at the Third World Water Forum, Unesco's director-general, Koichiro Matsuura, said: "Unesco will provide the water community with the necessary resources, the favourable environment, political backing and judiciary mechanisms to anticipate, prevent and resolve water conflicts."
In fact, the experience of history gives grounds for optimism that water disputes are unlikely to explode into violence between nations.
The last full-scale war directly linked to water was 4,500 years ago between the civilisations of Lagash and Umma on the River Tigris, ironically in present-day Iraq.
And even countries confronting one another on most issues have often continued co-operating over water - India and Pakistan have long-standing agreements on the River Indus, and the one part of the Israeli-Palestinian peace accord which has had some success is the water-sharing agreement.
THIRD WORLD WATER FORUM
If current trends continue, we could be faced with a very grave situation
Many feel that the real potential for conflict arises from the social disruption caused by growing competition for scarce freshwater supplies.
Professor Aaron Wolf, of Oregon State University, US, who carried out a major study of river basins for the UN, points out that 70% of the world's water is used for agriculture.
He told BBC News Online: "When those agricultural supplies are threatened, what it means is unemployed, disgruntled people moving to the cities which is the potential flashpoint.
"Interestingly, those states which are most dependent on irrigation water and where the irrigation water is threatened are precisely the states which are of most concern to the world's community for security reasons.
"We're looking at Iran, Iraq, Pakistan, India, Egypt - this is the region where irrigation supplies are most threatened, and where that threat really could lead to regional instability."
And campaigning groups at the forum say injustice in the way water supplies are distributed within countries also has the potential for growing violence.
POTENTIAL CONFLICT ZONES
River basins judged by Unesco to have 'potential for dispute in the coming five to 10 years'
Ganges-Brahmaputra; Han; Incomati; Kunene; Kura-Araks; Lake Chad; La Plata; Lempa; Limpopo; Mekong; Ob (Ertis); Okavango; Orange; Salween; Senegal; Tumen; Zambezi
Patrick McCully, of the International Rivers Network, said: "We already see in places like western India where people are dependent on tankers bringing them water, sometimes the government doesn't bring the water in on time or it's contaminated - these have sparked water riots and people have been killed.
"In the province of Sindh in southern Pakistan, we've seen a lot of protests because the delta of the Indus is basically not getting any water; it's all been diverted by dams and barrages upstream. We're going to see an increase in this type of conflict."
But as Mr McCully points out, disputes over water are nothing new: the word rival comes from the Latin rivalis, meaning one using the same stream as another.