Large-scale freshwater provision in low-lying areas of the Netherlands through smart use of the subsurface


Water authorities, drinking water companies, knowledge institutes, consultant Arcadis, the Province of South Holland and the greenhouse horticultural sector have today committed themselves for three years to the further development of COASTAR, an innovation in freshwater management. The eleven parties today signed a declaration of intent during a conference in Scheveningen, which was opened by Delta Programme Commissioner Wim Kuijken. COASTAR is an innovative solution involving the temporary storage of freshwater in the deeper subsurface for its use at a later time. COASTAR can also involve the abstraction of brackish groundwater, which can reduce salinisation of groundwater and surface water, and provide a possible extra source for the production of drinking water and irrigation water. COASTAR keeps ‘saline at bay, and fresh on hand’, and can be implemented in other delta areas worldwide.

The Dutch delta is one of the most densely populated and industrialised areas in the world. Its freshwater requirements are therefore huge. Climate change, rising sea levels, land subsidence and groundwater salinisation are however making freshwater increasingly scarce. At the same time, periods of heavy precipitation are becoming more frequent. All of this rainwater could offer a solution for freshwater shortages, but above-ground storage of rainwater requires far too many, and expensive, square meters of space. A large portion of this temporary precipitation surplus therefore flows away unused, while horticulturalists and industry regularly confront drought conditions. COASTAR (Coastal Aquifer Storage and Recovery) is founded on a new approach to the freshwater challenge in low-lying areas of the Netherlands, in which smart use is made of the surrounding environment and the subsurface.

From proven concept to large-scale realisation

Over the last few years a wide consortium of market players, research organisations and governments has engaged in the development and elaboration of COASTAR. The initiative was taken by Allied Waters, a public-private partnership dedicated to translating science for market uptake, the knowledge institutes Deltares and KWR, and the international consultancy Arcadis. The initial exploratory research phase, co-financed by the Water Top Sector programme, was concluded today with the conference in Scheveningen. The initiators presented practical, developed examples in which COASTAR can contribute to solving freshwater and other water challenges in the region of The Hague-Westland-Rotterdam. From now on, their aim is to work with other parties in identifying further realisation possibilities and larger-scale applications in South Holland and elsewhere.

More robust freshwater provision

Eleven parties today signed a declaration of intent, in which they firmly commit themselves to the further development and application of COASTAR. The parties are the Province of South Holland, the water authorities of Delfland and Rijnland, drinking water companies Dunea, Evides and Oasen, LTO Glaskracht, Allied Waters, Arcadis, Deltares and KWR. The consortium’s first step is to establish a knowledge programme for COASTAR, for the purpose of further elaborating concepts and testing them in practice. The ultimate objective is to enable well-founded decision-making in 2021 about possible future COASTAR realisations. In his address, Delta Programme Commissioner Wim Kuijken stressed the importance of the wide COASTAR coalition and the collaboration with the Delta Programme. He made a call on all the partners: ‘Seek connections. This will reinforce the position of COASTAR as a promising measure.’ Visit coastar.nl to follow the developments.

From left to right: Increase fresh groundwater supplies; Control salinisation; Control seepage of brackish groundwater; Temporarily store freshwater; Abstract brackish water; Optimise freshwater abstraction; Fresh/Brackish/Saline>.

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