Delta Life 10

20 Dry, drier, driest Large parts of Europe struggled with persistent drought this spring and summer. Meteorologists say that this is a taste of the future. How can we tackle water scarcity? An overview of five responses. BY RODY VAN DER POLS / PHOTO RUTGER HOFSTE STORING FRESHWATER IN THE SUBSURFACE It rains cats and dogs day after day and then not a drop falls for weeks on end. In many places - and certainly in the Neth- erlands - freshwater is mainly an issue of distribution: how can you make the enormous amounts of water at one time of the year available during a drought? Simple: by storing it underground at peak times. But is this feasible on a large scale as well? Deltares conducted a study un- der the COASTAR flag (COastal Aquifer Storage And Recovery) in collaboration with KWR Water Research and Arcadis, as well as drinking water companies, wa- ter authorities, municipalities, farmers and the province of South Holland. 'The answer is clear: yes,' says Esther van Baaren of Deltares. 'As long as everybody involved works together closely. That's the focus of our work now for the prov- ince of South Holland. But this approach can, broadly speaking, be used in any delta.' For more information: esther.vanbaaren@deltares.nl coastar.nl | go-fresh.info BRACKISH IS THE NEWFRESH The groundwater in the coastal provinces of the Netherlands is often brackish: a mixture of fresh and salt water. 'Brackish water has a bad reputation. Wrongly, because it is very clean and it doesn't contain any pesticides,' says Gualbert Oude Essink of Deltares. 'If you take the salt out, it can easily be used as drinking water. So I of- ten say that brackish is the new fresh. It's hardly surprising that the dune water company Dunea asked us to find out how much brackish water could be extracted from the Meijedel/Berkheide dune area.' The COASTAR research project (see col- umn 1) calculated that capturing and de- salinating all the brackish and salt seep- age in the Netherlands would produce 1800 million cubic metres of extra fresh water. Esther van Baaren: 'Even if you desalinate just some of it, that is an enormous increase in the amount of drinking water. And there's an added advantage: the "salt load" in the surface water system is reduced so that crops are less likely to be damaged by the salt.' For more information: ester.vanbaaren@deltares.nl coastar.nl FLEXIBLE WATER-LEVEL MANAGEMENT This summer, on 24 July, the Climate-Resilient Wa- ter Supply Facility (KWA) was turned on for the third time, sending 15,000 litres of fresh water a second in a westerly direction through a sluice in Bo- degraven to maintain the supply of fresh water. This alternative supply route was needed because the water at the regular intake point at Gouda was too salt. 'If not enough water flows towards the sea, salt seawater will move inland. That results in salinisation, and all the associated consequences for agriculture, drinking water and nature,' says Judith ter Maat, who represents Deltares on the Freshwa- ter Delta Programme. The programme has identified ways of making freshwa- ter distribution in the Netherlands more robust. 'One of the measures is more flexible water-level management,' says Judith. 'It allows us to store more water in the wet months - for example in the IJsselmeer lake - and use it in dry peri- ods. It is interesting to see how things we introduced with a view to the expected situation in 2050 are already proving to be useful in the present extreme condi- tions.' For more information: judith.termaat@deltares.nl tinyurl.com/dpzoetwater 1 3 2