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Water in the Balance

  • Written by  Paul Younger
  • Published in UK
Flooded fields Flooded fields Luke MacGregor/Reuters
19 Mar
2013
As southeast England mops up after another bout of serious flooding, last year’s drought seems a world away. But it raises the question – how can we reconcile floods and droughts and give the country some form of hydrological stability? Paul Younger suggests a solution

 The southeast of England has taken a hydrological battering in recent years, with prolonged periods of drought punctuated by intense storms that have led to repeated, widespread flooding. As I reflect on recent hydrological extremes in the region, it’s difficult to resist the temptation to say ‘I told you so’ – albeit mine was but the least of the voices, a decade and more ago, that were warning decision-makers about precisely the sorts of conditions now faced by residents of the region. 

These warnings – which I take no pleasure in seeing realised – were based on analyses of two human-made phenomena: climate change and over population. Neither of these show any sign of abating in the foreseeable future, so it’s vital that we find a way to adapt to them.

water2Residents wade through flood water at Barnham near Chichester

worst-case scenario
I was fortunate enough to work on predictions of the impact of climate change during the early days of the science. Our early work, funded by the European Commission in 1993, considered the potential impacts of climate change into the first few decades of the 21st century. We analysed three scenarios: ‘worst case’, in which there would be no abatement of the rate of increase in greenhouse-gas emissions; ‘median’, which assumed that governments worldwide would actually achieve something along the lines of the original aspirations of the Kyoto protocols; and a wildly optimistic scenario of a ‘fossil free’ future commencing promptly during the mid-1990s. 

The predictions clearly showed that the south of England could expect more periods of drought, while the north would get wetter. Subsequent analyses by colleagues, using more sophisticated models, indicated that these changes would probably be accompanied by increased storminess and growing year-to-year variability. And depressingly enough, nearly 20 years later, the weather we’ve been experiencing lately has pretty much tracked
the upper boundary curve of ‘worst-case scenario’ conditions. 

In parallel with the changing climate, national governments of all complexions have only deepened the void of responsibility for water-resources management that was created by the privatisation of the water industry in 1989. Where the UK previously had a Water Resources Board charged with taking a strategic overview of the requirements to achieve integrated management of water within and among catchments, in the post-privatisation world, no organisation has had any such responsibility. 

The National Rivers Authority and its successor, the Environment Agency, have occasionally tried to provide constructive overviews and recommendations, but they can’t prescribe solutions, and it’s left to individual water companies to develop their own strategies to ensure security of supply for their customers. 

Back when I worked for a water company during the 1990s, I once suggested that we ought to oppose a proposed large development in a water-scarce area on the logical grounds that we had no idea where we would get the extra water from. The response from senior management was swift and simple: ‘We never
turn down an opportunity to increase the number of our customers.’ Fifteen years later, the same company is locked in a dispute with the Environment Agency, which believes that the company’s licensed abstractions in the area far exceed even the most liberal estimates of the quantity of water available for exploitation. 
Plus ça change

water3Bewl Reservoir near Lamberhurst

responsibility vacuum
Nowhere has the vacuum of responsibility for water-resources planning become more profound than in the southeast of England, where we’re now reaping the consequences of reckless governmental decisions made years ago. As far back as 2001, the Environment Agency was warning that ‘in an average year, there is less water per person in England and Wales than in Spain or Portugal. In parts of the South and East of England, there is less per person than in Ethiopia or Sudan. This scarce resource needs very careful management if we are to ensure that there’s enough for us to use in our homes, in industry and for agriculture… The natural environment also needs water.’ 

It’s remarkable that consideration of the water needs of the natural environment were a mere afterthought in a statement from the Environment Agency, but regardless, these comparisons are misleading. For a start, rainfall on its own is a poor correlate of available water resources; if you take into account evapotranspiration – the sum of evaporation and plant transpiration from the land surface to the atmosphere – England emerges in far better shape than most of Africa. Per capita estimates are also strongly dependent on population density, which is far higher in southeast England than in Sudan or Ethiopia. 

Nevertheless, the overall message is clear: by 2001, southeast England already had no water resources to spare. So what came next is all the more remarkable.

reaching limits
In 2003, the Office of the Deputy Prime Minister (ODPM) launched a consultation on its disingenuously named ‘Sustainable Communities Plan’ for southeast England and the Thames Gateway area. The plan envisaged the construction of around 800,000 new homes. In due course, the Southern Regional Office of the Environment Agency submitted its comments on the plan, stating that ‘the development of 800,000 new homes in the Southeast could set off an environmental time-bomb’.

The director for the agency’s Thames region commented that ‘in some parts of the region, we are reaching our environmental limits. Unless the environment is built into plans for development now we will seriously threaten the quality of life in the Southeast.’ The ODPM minister responsible at the time, the since-disgraced Elliot Morley, responded with apoplexy, betraying a deep-seated governmental hostility to supposedly ‘arms-length’ public bodies that indulge in free thinking. Morley dismissed the Environment Agency’s concerns, saying that its views were merely those of ‘a regional office. It was not the Environmental [sic] Agency centrally that said that.’ 

The notion that the national headquarters of any body is likely to have a better idea of what’s happening on the ground in a given region is, of course, absurd. Morley went on to claim that the agency’s views were based only upon what it perceived as ‘a lack of forward planning’. 

The Environment Agency nationally was clearly rattled, and chose its words carefully when it replied that ‘development on the proposed scale would result in environmental pressures in the region if environmental issues are not fully considered as early as possible in the planning process’. 

So hydrologically reckless development proceeded apace for another four years in the Southeast with ODPM sanction. It was only finally checked by the global financial crisis of 2008. Pressures on water resources in the Thames Gateway area grew so unbearable that Thames Water achieved an ignoble first
in the history of the UK water industry when it commissioned a desalination plant at Beckton, to ensure security of water supply during periods of drought and/or high demand. 

This desalination plant is the largest in Europe, capable of producing up to 150 megalitres per day – about enough to supply a million people. It was built in the face of fierce opposition, both to its CO2-emission implications and to its potential to lessen pressure on the water company to reduce leakage rates in Central London, which remain high by European standards. Of course, if you buy the guff that southeast England is truly comparable to drought- and poverty-stricken East Africa, this might not seem like an illogical solution to the slow-motion train crash that passes for water-resources planning in the region today. 

 

storage solution
But is high-cost, high-carbon desalination all that we can aspire to in southeast England? The traditional approach to coping with periods of drought is simply to store more water, which was traditionally done by constructing surface reservoirs. But dams and reservoirs get bad press these days, mainly from environmental campaigners incensed by the insensitive manner in which they are constructed in many developing countries, sweeping communities aside before their villages are forever drowned. 

While one would hope that British planning laws would prevent the worst of such excesses, new surface reservoirs have been off the agenda in the Southeast for generations, as land prices in rural areas, combined with high population density and a reasonable desire to preserve what little remains of ‘natural’ landscapes, make it almost impossible to identify suitable sites for new surface reservoirs large enough to make a difference. 

water1A recycled water aquifer storage and recovery trial site in South Australia

Some companies have been actively raising existing dams, yet still there is insufficient storage to remove desalination from the agenda. Is there another way to balance floods with droughts to the benefit of water resources? 

Fortunately, there is. All of the problems that beset surface reservoirs can be avoided by storing water underground, through a process known
as aquifer storage and recovery (ASR). This is achieved by seasonally injecting excess water (for example, storm runoff) into subsurface strata using boreholes and/or ‘spreading basins’ (that is, lagoons with permeable bases). When demand for water increases, the stored water is retrieved by pumping from boreholes. 


first steps
Large-scale ASR systems have been running successfully for many years in Florida, Australia, and even in North London, where excess water is pumped into the chalk aquifer from the London Ring Main during periods of low demand, and pumped back out again when demand peaks. Not only does this create a strategic store of water; it also helps to lower pressure in the Ring Main, thus contributing to a reduction in the propensity for leakage. 

ASR has almost no surface footprint and can be developed piecemeal, a borehole at a time, as water demand grows. And southeast England, as we’re forever being told, has many depleted aquifers that would readily lend themselves to redevelopment as ASR reservoirs.

It has now been some three decades since the UK last invested in ASR on a large scale; the North London scheme was typical of integrated water-resources planning in the long-gone days before privatisation. I believe that it’s high time that we began seriously assessing the scope for ASR throughout the Thames, Anglian, Southern and Wessex water-supply regions – and, indeed, further afield, in the many parts of the UK where water scarcity coincides with depleted aquifers. 

The first steps in this direction are now being taken by Southern Water in the South Downs Chalk Aquifer; here’s hoping that they’re the first steps of many.

Julysub 2020

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