Britain is running out of water

Drier summers and a rapidly growing population mean parts of Britain will run out of water in 25 years. What can we do about it, and how much would it cost? Simon Wilson reports.

What's happened?

Earlier this month the chief executive of the UK's Environment Agency, Sir James Bevan, issued a stark and sobering warning that unless we take action now, Britain is facing a serious and potentially catastrophic shortage of water within two to three decades. Demand for water is rising steadily as the population increases. But supply is projected to fall as the effects of climate change kick in.

If you plot the rising demand and the falling supply on a graph, at some point in the 2040s those lines will meet and cross. That point, says Bevan, is "the jaws of death the point at which, unless we take action to change things, we will not have enough water to supply our needs".

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What are the figures?

The government expects the population of the UK to continue rising from 67 million now to 75 million by 2050 implying more houses, roads, workplaces, energy, and food, all of which will require more water use. Meanwhile, climate change means that we are likely to have less predictable rainfall, and hotter and drier summers, with more than one in two summers by 2040 hotter than the 2003 heatwave.The Environment Agency projects that by 2050 the amount of water available for "abstraction" extraction from rivers, lakes, groundwater aquifers and so on could be 10%-15% lower, and that some rivers will have 50%-80% less water during the summer months. All of this means that "many parts of our country will face significant water deficits by 2050", says Bevan. The upshot: "an existential threat".

But isn't Britain a sodden island?

Yes, but much of our rain falls on particular bits. The UK's average rainfall is around 1,200mm a year. That's about half as much as the Philippines, Nicaragua or Sierra Leone, but twice as much as Spain, or Poland. What's striking about the distribution of rainfall in Britain, explains Tim Smedley, author of Clearing the Air, is that the rainy highlands of Scotland, Wales and northern England account for much of the average figure. In the UK's most densely populated area by far, the south east of England, the average annual rainfall is only around 500-600mm. That's less than South Sudan, or Perth in Western Australia.

Why is that significant?

Because the London and the Thames Valley region is already classified by government officials as "seriously water stressed". According to Steve Tuck, abstraction manager for Thames Water, the region has "relatively small water storage facilities, which means we take from rivers and groundwater aquifers to supply the large population" in a system that has become worryingly "hand to mouth". In other words, it wouldn't take much to tip us into a crisis if weather patterns change faster than expected.

Last year saw six consecutive months of below-average rainfall in England, causing many reservoirs to run dangerously low, and 2017 saw the driest ten-month period for more than 100 years. And already the levels of abstraction from 28% of groundwater aquifers in England, and up to 18% of rivers and reservoirs, is classed as unsustainable. All this means that England "offers a case study of how previously wet countries will have to wake up to a future of increasing water scarcity", says Smedley.

How much water do we use?

Slightly more than half of the fresh water in the UK is abstracted for household use (compared to just 1% for agriculture), and on average we use 150 litres of water a day far higher than comparable rich European countries including Germany, the Netherlands, Belgium and Denmark.

If we need to start cutting our usage (and we do), the obvious place to start would be to put a market value on water via compulsory metering, says Ross Clark in The Daily Telegraph. Currently, 52% of UK households are still allowed to help themselves to as much water as they like for a flat monthly fee. Bringing in a proper market would cut wasteful usage and incentivise investment in new infrastructure.

What else do we need to do?

Cut leakage: almost every country that has carried out successful water efficiency campaigns has mandatory metering. But it also has the added benefit of helping the water company to detect leaks. Currently, three billion litres a day leaks out of aged pipes in the UK a volume equivalent to the water used each day by 20 million people. Bevan reckons that cutting this in half is a realistic target, along with cutting average individual consumption by a third.

In addition, the UK will need to build more desalination plants. The first of its kind, in Beckton, east London, opened in 2010 and provides up to 150 million litres a day, though it uses a lot of pricey electricity. We'll need more reservoirs (none has been built for decades). Furthermore, we'll need to invest in pipelines and canals that can transfer water across the country (from the Severn basin to the south east, for instance).

All sounds horribly expensive

Yes, but it's probably less horrible than the alternative. According to the government agencies paid to investigate the issue, investing heavily now to mitigate future water risks is a no-brainer. A report last year by the National Infrastructure Commission on the risks of extreme drought in Britain supported a twin-track approach of reducing demand and enhancing supply, and concluded that the investment cost of ensuring resilience (£21bn) is roughly half the cost of one extreme drought event (£40bn).

A 2016 report by the Environment Agency reached the same conclusion. "While a severe drought would cost each household more than £100, the cost per household of the investment that would greatly reduce the risk was only £4 a year."