Competition for scarce water resources is increasingly a source of political tension. Engineering can play a major role in defusing it, reports Andrew Mylius.
It is being dubbed 'liquid gold' and the 'white oil of the 21st century'. Fresh water - regarded as a birth right by nations of people - is now among the most prized environmental assets in the world. Despite the flooding of Honduras, Bangladesh and Mozambique, water's increasing scarcity has caused its value to rocket in recent years. Where water is in shortest supply governments cherish and jealously watch over it. They are even prepared to wage war over it.
Water rights are at the centre of tensions between Israel and Jordan. Ethiopia, Sudan and Egypt are guarding their stakes in the Nile. Syria and Iraq have warned Turkey they will take up arms if flows of the Tigris and Euphrates rivers are diminished as a result of Turkey's ambitious dam building programme.
'Following the close of the cold war, political science refocused on environmental conflict,' notes Centre for Ecology & Hydrology deputy director Frank Law. Water is a politically volatile issue, he says.
The danger of conflict over water is global, and set to become increasingly acute. The World Bank estimates that in the next quarter century the numbers of people facing water scarcity will rise from 1.2bn to 3bn. But it is the southern hemisphere where resources, and diplomatic relations, will be most stretched.
Specialist in north-south relations Guy Arnold distils the issue: 'There is a lot of water in the world, but in the wrong places for most people.' Making water available where it is most needed is a challenge of enormous magnitude, he says. With political will and heavy duty investment, though, it is technically feasible. 'When the price of water sky rockets, people will be far more willing to put money into infrastructure,' he predicts.
Foreign & Commonwealth Office deputy head of environmental policy Peter Hayes agrees that the rising value of water is key to exciting interest among private sector investors in the provision of dams, pipelines and canals.
Dams, in particular, are needed. To maintain even today's inadequate levels of water provision, more than 20% extra fresh water storage capacity is called for by 2025, the Department for International Development states in its consultation document Addressing the Water Crisis. Meanwhile, an estimated 70% of available fresh water occurs as floods. In many of the most hydrologically challenged areas, the problem is not that it never rains. It simply rains too much and at the wrong times, creating cycles of flood and drought.
'Engineers can play a crucial role in storing water and reducing seasonal disparities in availability,' says Overseas Development Institute research fellow Alan Nicholl. Despite international outcry over current dam building projects - Turkey's proposed Ilisu hydro-electric project on the Euphrates river is the latest to be slated - 'pressure to build dams won't go away', says Nicholl. 'In the next 25 years it will actually get more acute.'
It is the threat of conflict between countries that will make headlines in the UK. However, where water shortage is most critical, in southern Africa, South and central Asia, and the Middle East, conflicts are in the main local and regional.
Animal rearing pastoralists, crop growing agriculturists and yearly swelling cities are locked in combat for dwindling flows. In Sri Lanka last year, for example, rice farmers overpowered water authority workers at a reservoir and forced open the gates. They were angry that their paddy fields were dry, depriving them of a harvest, while the wealthy of capital city Colombo were assured water.
Fears are that inadequate supply will hold back agriculture, making it impossible for many countries to feed themselves. At the same time the masses crammed into the world's 30 or so megacities - those with a population of between 15M and 30M - will be forced to endure increasingly squalid living conditions.
Foreign & Commonwealth Office deputy head of environmental policy Peter Hayes reports that water issues are at the heart of FCO drives to improve economic and political stability in the former soviet states of Central Asia.
To meet local demand Nicholl believes construction of bigger dams is inevitable.
Although smaller dams may sound less awkward politically, they are less efficient, he claims. A greater surface area is required to store water in several low volume reservoirs than as a single body. More land is lost and more people displaced. And in Africa, where more than a quarter of impounded water is lost through evaporation, resource management makes a compelling case for deep reservoirs with small surface area to volume ratios.
If engineers can look forward to a surge in dam construction, they should also anticipate getting involved in painstaking river basin studies. Hayes says the Foreign & Commonwealth Office is concerned that donor agencies such as the World Bank give very serious attention to the impact of water projects on downstream nations.
Telford Challenge programme director Dominick Verschoyle explains: 'You need to decide how water is split between users and uses, where dams are built, and their impact on communities, agriculture and fisheries.'
Irrigation can make agricultural land saline, ultimately defeating the objective of improving agriculture, he notes. Land on historic flood plains can be drastically depleted if annual flooding stops. Fertilisers can leach into down stream waters playing havoc with aquatic habitats. River flow changes and new siltation patterns can damage navigation.
Each issue gives scope for grave conflict. And there is huge potential for inter-regional or inter-nation antagonism where abstraction levels are disputed. Jordanian and Syrian tempers flared during last year's drought when Israel, which controls abstraction from the River Jordan and fresh water Sea of Galilee, cut back supply by 40%. Israel reduced consumption but its self-imposed cuts were far less stringent.
But there is hope. In the long-term, demand for water combined with the complexity of distributing it could force co-operation claims Nicholl. There are more than 70 internationally brokered water basin initiatives worldwide. Negotiation is leading into development of water allocation and resource trade agreements.
'In coming decades the Democratic Republic of Congo will probably be selling water and power generated from the river Congo to South Africa, Zimbabwe and Namibia,' predicts Arnold.
The FCO and private investors are attempting to broker deals between former Soviet states Tajikistan and Kirgistan, which command 80% of the region's water, and arid but oil-rich Uzbekistan and Turkmenistan.Transporting water is going to require 'major infrastructure'. Libya is driving ahead with its Great Man Made River project, tapping into vast aquifers to green the desert and quench the thirst of Tripoli, Benghazi Sirt and Tobruk. Egypt has similarly vast bodies of fresh water locked beneath the Sahara.
In the wider world, the growing commercial value of water is also making desalination increasingly viable.
The engineers that help realise these water supply opportunities will be this century's most valued peace keepers.