Water & Wastewater Treatment Magazine
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www.wwtonline.co.uk | WWT | AUGUST 2019 | 11 thresholds in river reaches where ground- water abstraction is the main influence on flow. "The reductions across the whole of England are potentially huge," Soley says. "We'd need to switch off more than one-third of all existing groundwater abstraction across public supply, agricultural and other sectors. If demand is not also reduced, the supply replacement cost would be enormous. I think, with some exceptions where the groundwater level or river flow recovery would indeed be significant, that money could deliver more direct ecological benefits if spent on habitat restoration and/or catchment-based water quality improvements. "If such largescale reductions were implemented, we would also be clos- ing down groundwater storage assets which will become increasingly essential for both public supply and agriculture in the future as the climate warms and drought periods become more prolonged. Groundwater is complicated and tends to confound simple expectations, so reduc- tions need to be considered carefully to avoid disappointment." Soley is keen to emphasise that there are clear exceptions: he began his work in the field on the Redgrave and Lopham Fen restoration project in the late 1990s, which saw collaboration between Essex & Suffolk Water, the EA, Suffolk Wildlife Trust, Natural England and the European Union to restore the biodiversity at a wetland by relocating a borehole. "That's a great example of where a local abstraction relocation has had a noticeable and widely acknowledged benefit that brought about environmen- tal improvements," he says. "It made a real difference. There are also effec- tive groundwater to river augmentation schemes operated occasionally by both the Environment Agency and water companies which can help to maintain flows and reduce the ecological impacts of drought whilst allowing other abstrac- tions to continue." APEM is working with the EA to help ensure that interventions on abstraction take place in those areas that will bring about real change. "The evidence base is still a little bit weaker than, say, for water quality issues," Cadman says. "I think over the next few years we'll see quite a few changes to how things are done and that we'll be able to model and predict those impacts with a bit more accuracy. "I think we'll have to do two things: we'll have to get a bit smarter about abstraction and overall it may have to reduce." Alternative solutions Regardless of the extent to which the water company of the future might be obliged to reduce freshwater abstraction, there is clearly a need to consider how to optimise the use of supplies to protect against the pressures of population growth and climate change. Water Resources South East (WRSE), an alliance of the six water companies in south-east England plus the EA, Ofwat, Consumer Council for Water, Natural Eng- land and Defra, focuses on developing more resilient and sustainable forms of water. Trevor Bishop, WRSE's organisational development director, believes abstrac- tion reduction is an important goal since, beyond the environmental benefits, it may also prevent an overreliance on supply sources that could prove to be less reli- able under future changes in climate and drought. "If you can conserve this precious resource through demand management and reducing leakage, for example, there's more to go around, more for the environment, and also more available for when pressures really bite," he says. While regional groups, water companies and regulators are all working together to ensure timely action to balance future demands and supply, there is no room for complacency. Part of WRSE's work is to understand how the various pressures might grow into the future, and Bishop highlights that, while agriculture is responsible for around 50 to 60 per cent of abstraction in many countries, that figure is around 1 per cent nationally here. "We don't have the same agricultural demand at the moment, but we're all doing some work at the moment to look at what agricultural need might be in the future, post-Brexit etc," Bishop says. "It's unlikely to increase to the kind of levels we see in Mediterranean countries but it might well increase, so we're including that, and the needs of other sectors, in our regional mod- elling approach." In March, the BBC pointed out that the average annual rainfall in the south east is around 500-600mm, which is less than Perth in Australia, but work has taken place there that may help provide a route forward for the most water-stressed parts of the UK. "In Perth, the millennial drought hasn't ended," he says. "That's probably the most westernised area where they're experiencing what could be a permanent shiž in climate – it's getting on for four decades now." • STATISTICS • In 2018, approximately 11,500 megalitres was abstracted per day. Leakage as a percentage of all water abstracted stood at 22 per cent • Abstraction from around 28 per cent of groundwater bodies and up to 18 per cent of surface waters was found to be at higher than sustainable levels in 2017 • Unsustainable abstraction prevented at least 6 per cent and up to 15 per cent of river water bodies from meeting good ecological status or potential in 2016 • In 2014, 77 per cent of chalk streams failed to meet good ecological status. When a sample of these streams were tested further, abstraction was found to be the primary contributing factor in around a quarter of cases • The EA aims to bring 90 per cent of surface water bodies and 77 per cent of groundwater bodies up to good ecological status as a result of water resources by 2021 (Source: Environment Agency) Perth, Australia, has reduced abstraction from dams from 92 per cent to 7 per cent WATER RESOURCES