Water shortages are predicted to be the catalyst for 21st Century conflicts as E&T explains.
The history of the late 20th century was pockmarked with various conflicts whose roots could be traced back to oil and securing its safe supply. According to the United Nations, however, that is changing, and water could be the next resource that triggers wars around the globe as countries become increasingly aware of the need to secure a long-term supply.
The waters of a number of major rivers - such as the Mekong, Indus, Nile and Amazon - are shared between two or more countries. International river basins cover 45 per cent of the Earth's land surface. They provide water for about 40 per cent of the world's population, and account for approximately 60 per cent of global river flow.
If India wants to dam a Himalayan river that ultimately delivers water to Pakistan, tensions will arise. Likewise, Egypt has an awkward relationship with Ethiopia, in whose highlands the Nile begins its journey to the Mediterranean. The damaging effects of climate change could well restrict the natural supply of water just as demand is peaking.
'Those who have studied water conflicts find almost none where water triggered the conflict,' Daniel Zimmer, executive director of the World Water Council, says. 'Water is ultimately a source of collaboration rather than war. It is so vital, you cannot afford to have a war over it.'
But at the local level relations are often more fraught. Tension over the allocation of water resources is far more prevalent within countries' own borders. Increasing agricultural production by increasing irrigation, for example, may leave less water for downstream users.
In Darfur, access to water and land has been a major factor in a conflict between black farmers and Arab nomads. Drought and desertification in North Darfur led the Arab nomads to move into South Darfur, where they came into conflict with black African farmers.
In China, the government was criticised by local officials in north-western provinces for diverting water from these regions to Beijing to flush out the city's polluted rivers and lakes in time for the Olympics.
The third UN World Water Development Report, published last year, stated that water is linked to the crises of climate change, energy and food supplies and prices, and troubled financial markets. 'Unless their links with water are addressed and water crises around the world are resolved, these other crises may intensify and local water crises may worsen, converging into a global water crisis and leading to political insecurity and conflict at various levels,' the report says.
It goes on to explain that action is required now, and it is hard to argue against that. Lives and livelihoods depend on water for development. After decades of inaction, the problems are enormous. And they will worsen if left unattended. But while the challenges are substantial, they are not insurmountable.
Alongside the natural forces affecting water resources are new human activities that have become the primary 'drivers' of the pressures affecting our planet's water systems. These pressures are most often related to human activities and economic growth.
Our requirements for water to meet our fundamental needs and our collective pursuit of higher living standards, coupled with the need for water to sustain our planet's fragile ecosystems, make water unique among natural resources.
But this shortage of water poses a question. It's a simple question but one that could be at the root of future disputes. Who actually owns the water? Does water flowing through one country or region belong to that country? Or does every region it passes through have equal rights to its use? Can one country or state dam a river to preserve it for its own use to the deteriment of others further downstream?
California water wars
There is no better example of the conflicts water can cause than in California. At the turn of the 19th century, newly-elected mayor of Los Angeles, Frederick Eaton, dreamed of a city that rivalled New York to the east, but his grand plans were being thwarted by a lack of water. He appointed his friend William Mullholland to director of the Los Angeles Department of Water and Power (LADWP) and between them began to redress this inbalance.
There was water aplenty 200 miles to the north in the Owens Valley. Eaton set about buying the water rights while Mullholland began constructing a giant aqueduct. The Los Angeles aqueduct ran for 233 miles and was completed in 1913, transporting water through 164 tunnels from the Owens River to a reservoir in the San Fernando Valley. This began a new era for the city, and Mullholland famously said at the opening of the reservoir: 'There it is, take it.'
But what was good for Los Angeles was disastrous for the Owen Valley. What had once been a green and fertile land quickly turned into an arid waste. The once bountiful supply of water diminished to a trickle to such an extent that in 1924, Owens Lake completely dried up prompting an uprising from local farmers. They armed themselves and took over part of the aqueduct, dynamiting Alabama Gate. It was, however, all in vain.
Another project in the Western United States that illustrates the complexities of water ownership is the construction of the Hoover Dam. The dam was originally proposed with the dual aims of controlling the problem of flooding on the Colorado River as well as electric power generation.
There was minimal guidance on water allocation from the Supreme Court and supporters of the dam feared an endless round of legal challenges and delays so they adopted a novel solution. It was proposed that the seven states (California, Nevada, Arizona, Utah, New Mexico, Colorado and Wyoming) that lay in the path of the Colorado River form an interstate compact, with the approval of Congress.
Initially, talks between the gang of seven foundered until the Supreme Court handed down a decision which undermined the claims of the upstream states. The resulting Colorado River Compact was signed on November 24, 1922 and six years later the dam was authorised.
The changes in water use caused by Hoover Dam's construction had a devastating impact on the Colorado River Delta. The construction of the dam has been credited as causing the decline of this estuarine ecosystem. For six years after the construction of the dam, and while Lake Mead filled, virtually no water reached the mouth of the river. The delta's estuary, which once had a freshwater-saltwater mixing zone stretching 40 miles (64 km) south of the river's mouth, was turned into an inverse estuary where the level of salinity was actually higher closer to the river's mouth.
'Recent world events and natural forces, such as increased incidences of intense drought across the US, compel policy makers to address water security issues,' says Jesse J Richardson Jr, associate professor of urban affairs and planning at Virginia Tech and author of the report 'Who Owns Water'. 'Policy responses must consider existing legal framework or risk reversal in the courts. Legal principles often shape final policy by prohibiting some responses while allowing or even facilitating others.'
Water supply and water rights concerns often present uniquely novel and complex issues. However, courts often rely on well settled, but ancient, legal doctrines in deciding water rights issues. Many courts and legislators also lack a basic understanding of the complex science of hydrology.
'Water law and security in the United States draw from several areas of the law, including private property rights, local, state and federal environmental laws, federal and state freedom and information rules and state laws regulating public service authorities. The fragmented nature of the regulation of water and water security prevents a thorough review of all areas of the law impacting water.
'Often, water rights conflict with water security policy by, for example, preventing control of water resources by government agencies. The takings clause prevents local, state and federal governments from seizing groundwater or surface water for public purposes without just compensations. The public trust doctrine, contrary to popular belief, fails to excuse governmental agencies from this obligation.
'However, state and local governments may regulate water to advance the public good so long as this regulation stops short of a taking. Drawing this line presents difficulties for policy makers.
'On the other hand, a system of dispersed private water wells presents a difficult target for terrorists, as opposed to a single public water supply source. Use of private water wells for the primary water supply, or even back-up system, should be encouraged.
'Most importantly, policy makers must seek to understand the basic legal framework of common law water rights and allowable legislative alternatives to those rights. This understanding allows policy makers, federal and state agency experts and other to pursue research on water security alternatives that will result in legally defensible policy decisions.'