Subsurface as a solution for a robust freshwater supply


voorkant COASTAR rapport

Using the subsurface to resolve water issues: it’s a well-known approach for the Dutch water companies, who have been counteracting salinisation of drinking water sources by applying surface water infiltration in the coastal dunes since mid-way during the last century. However, KWR knows there are many more subsurface solutions yet to be discovered and that is why it is involved in the COASTAR (COastal Aquifer STorage And Recovery) programme. This programme aims for a large-scale use of the subsurface to contribute towards a robust and sustainable freshwater supply to combat drought and salinisation in coastal areas, both within and outside of the Netherlands.

Delta Works of the 21st century

COASTAR is an initiative of the SALutions Collab of Allied Waters, an international public-private partnership in which KWR acts as a knowledge partner for translating science into the water sector market. The first phase of COASTAR was successfully completed recently, with a report (in Dutch) about the benefit and need, as well as the technical and financial-economic feasibility of using large-scale subsurface solutions for robust freshwater supplies in the low areas of the Netherlands. ‘This programme has the potential of becoming the Delta Works of the 21st century’, says Klaasjan Raat, from KWR and co-initiator of COASTAR. ‘There are little technical barriers for the large-scale use of subsurface solutions for water issues. We just have to be daring, and COASTAR provides the perfect reason for that.’


Dual approach

COASTAR has opted for an integrated  approach instead of the normal Dutch focus on surface water systems for resolving water issues. The programme regards the use of the subsurface as the ultimate solution for robust freshwater supplies in coastal areas. The approach is a dual approach. Subsurface water storage serves as a bridge between water demand and supply as regards space and time, and salinisation is prevented by strategically capturing and using brackish water in the production of freshwater.


Worldwide commercial replication

The implementation of COASTAR brings together a wide range of sectors – drinking water, industry, agriculture, cities – and encourages water reuse. The concept phase will now be followed by detailed regional plan, a Master Plan, which aims to ensure self-sufficiency in the water supply for the region of The Hague – Westland – Rotterdam. By guaranteeing sufficient (future) freshwater supply, COASTAR will boost the business and industrial climate in the Netherlands. Ultimately, COASTAR’s ambition is worldwide commercial replication of Dutch solutions.