Large-scale water transfer projects have had a bad rap for good reason. But might they be the best means of guarding against future shortages? And can they be carried out sustainably

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Pont du Gard, France, a Roman aqueduct built circa 19 BC.

Large-scale water transfer projects have had a bad rap for good reason. But might they be the best means of guarding against future shortages? And can they be carried out sustainably? Ben Goldfarb investigates.

Last April, its reserves depleted by Britain’s worst drought in nearly 40 years, Anglian Water was hoping for rain. Summer lay ahead, and, beyond that, the threat of an unprecedented third dry winter in a row. If that were to happen, it would put a real strain on Anglian’s ability to meet the needs of its customers. The company, which services 27,000km2 in southeast England, had banned the use of hosepipes; but with no rain in sight, cutting usage wasn’t going to bridge the shortfall. There was no way around it: Anglian would need more water to ride out a drought stretching into 2013.

To Anglian’s west lies Severn Trent Water, whose district had not been nearly so afflicted. With Severn Trent still flush, and Anglian’s supplies diminishing, the two companies began negotiations on the transfer of water from one region to another. Their proposal would have seen navigation canals and the River Trent used to transfer enough water from Birmingham, in Severn Trent’s area, to the Humber Bank, in Anglian’s, to supply 100,000 homes.

Heavy rains arrived before the scheme was enacted, and now, says Mike Cook, Anglian’s Head of Water Resources, the company’s reserves are recharged. But while it won’t have to buy water from its neighbours this year, the negotiations have prepared Anglian for dry spells in years to come. “The transfer that we developed could be used in the future, if necessary,” says Cook. “It’s important that we be ready for the next drought.”

Small-scale water transfers have been occurring for decades in the UK. But as population growth intensifies demand for water, and climate change threatens to disrupt supply, companies are starting to think beyond local,ad hoc transactions. Last spring’s drought left England’s water purveyors contemplating more frequent and formal trading arrangements to ensure their districts never dry up.

A nationwide trading network may arrive next year, as the UK Government has mandated that water companies submit a long-term plan for managing the country’s resources by March 2013. While measures for reducing consumption, such as repairing leaky infrastructure, will factor into the plan, water swaps may well be central.

“The idea is to identify surplus within the system”, says Luke DeVial, Head of Environment and Resources atWessex Water, “and then all companies can enter detailed negotiations and consider trading options.”

England isn’t alone in pursuing transfers as a path to water security. California has conveyed water from the Sierra Nevada Mountains to Los Angeles via aqueduct since 1913. Libya’s Great Manmade River, the world’s largest underground network of pipes and ducts, moves 6.5 million cubic meters per day from an ancient aquifer beneath the Sahara Desert – enough water that one of the world’s driest countries aspires to export crops. And even Libya’s system is dwarfed by China’s ongoing South-North Water Diversion Project, channels that would transfer 23 trillion litres a year from the Yangtze and Han Rivers to Beijing and Tianjin. These hubristic undertakings, however, have traditionally led to steep environmental costs. China’s project has relocated hundreds of thousands of people, and the Han River may eventually be bled dry by canals. Diversions to cities in the southwestern US have reduced the Colorado River at its delta to a swampy trickle. Water transfers in Australia’s Snowy Mountains have choked rivers with silt, spreading invasive species and destroying fish populations.

Despite this dismaying record, England’s water companies believe they can promote ecological health rather than wreak havoc by using transfers to comply with the Restoring Sustainable Abstraction Programme, anEnvironment Agency initiative to reserve water for aquatic environments. Wessex Water, for example, agreed to reduce abstraction by seven megalitres from the Chitterne Brook, an unusual chalk stream that hosts juvenile trout. The company plans to compensate for the lost abstraction by linking places in its water-abundant south, like Dorchester and Shaftesbury, to Salisbury and other points further upstream by 2018.

Climate change, which portends severe summertime drought and variable rainfall, also motivates companies to pursue transfers. In 2010 United Utilities completed its West East End Link, a 55km-long pipeline that connects Manchester and the Lakes District so that water can move between regions when one goes dry. “The pipeline’s true test will come as climate change kicks in”, says Richard Blackwell, United’s supply and demand manager. “The link will be playing an important role in 100 years.”

Moving water between regions, however, is not without difficulty. Even plans that use existing canals require new infrastructure – pumping stations to lift water over locks, and new treatment facilities to process increased volume – which could impede cost-effectiveness. Companies may be able to defray these energy expenses by diverting their water through hydropower installations. According to Roger Falconer, Professor of Water Management at Cardiff University, England should look beyond its own borders to alleviate scarcity. Citing a 2010 report by engineer John Lawson, Falconer advocates flowing water from the River Severn to the Thames and enlarging Wales’ Craig Goch Reservoir in order to import water via the River Wye. “In principle, we could enact this plan right now, using existing rivers and canals,” says Falconer.

And while some Welsh environmental groups object to the export of their water, other people see it as a path to prosperity. John Jones, a former executive at Welsh Water, told the BBC last April that Wales’ best use of their abundant H2O might be to treat it like oil –– and sell it, at a tidy profit, to their English neighbours.

If the UK needs a guide to the promise and peril of international agreements, it should look to Southeast Asia. Singapore, which has few water resources of its own, has long relied on Malaysia for its water, currently drawing nearly 40% of supply from its neighbour and paying about1% (US$) for the privilege. Yet while Singapore benefits from access to cheap Malaysian water, its dependency is also a weakness that Malaysia exploits for political leverage. To escape Malaysia’s influence, Singapore has committed to weaning itself off foreign water, opening wastewater and desalination plants to ensure domestic supply.

Singapore isn’t alone: even as some companies and countries employ water transfers to mitigate against shortages, others focus on conserving water within their own districts. Methods to capture stormwater, such as Aquifer Storage and Recovery, are gaining primacy across the world, and greywater recycling will soon be standard practice in dry regions. And that’s just the supply side. England’s water companies are adamant that demand-side measures will be integral pieces in the country’s forthcoming water plan. Yet in a world increasingly dominated by climate change, they still see transfers as vital insurance, a means of staying flexible and resilient when rains vanish. “We can push and push on the demand side to reduce leakage and consumption”, says Anglian’s Cook. “But climate change will make it harder to recharge groundwater, and we’re going to need to pursue some bigger interconnections.”

Ben Goldfarb is a Master’s student at Yale University and the editor of Sage Magazine.

This article originally appeared in Green Futures, the leading magazine on environmental solutions and sustainable futures published by Forum for the Future.