Water supply in urbanising deltas
Throughout the world increasing populations in delta cities are putting severe pressure on the water supply. Problems, like inadequate supplies of good drinking water, or even floods, are quite common in numerous delta cities. Deltares develops new solutions in support of a more climate-robust and sustainable approach to water usage in these areas. This involves an integrated approach linking the hinterland to urbanized areas and research on opportunities to use the subsurface for water storage.
Climate change and lack of storage capacity may induce floods in cities. Also problems with heat stress and water shortages may occur with increasing frequency and intensity. Deltares studies water systems in relation to the urban water cycle. New promising solutions are studied in large scale field tests. In these so called ‘living labs’ we demonstrate proof of concept of new options for water storage . A good example is the GO-FRESH project (Geohydrological Opportunities Fresh Water supply) in the Province of Zeeland. This project has shown how fresh water storage can increase in coastal areas with brackish groundwater needed for the water supply to agriculture.
Mapping out the water system and delivering solutions
Deltares also develops operational water management systems to improve management of droughts (i.e. drought early warning systems). This involves integration of state of the art data with new tools to provide water managers with the best available information. Improvements on seasonal forecasting help managers to prepare and take adequate measures in developing drought situations. Here also an integrated approach is used taking into account surface waters and groundwater and the interactions between them. The systems also provide information on the economic impact of droughts. In addition, for delta cities in data poor areas specific software has been developed in support of analysis urban water supplies. This software is named ‘rapid assessment tools for urban water supply’ and shows how water flows and where possibilities occur for water storage. The tool is also helpful in defining first order measures for improving water supply, with underground storage (ASR or aquifer storage and recovery) as a central component.
New policy required
Besides new technologies, we need policy and legislation for cities to adapt and improve future water supply. Every delta city and its surrounding have specific governance issues. Deltares works with numerous partners, from research institutes to government agencies. For example, we often team up with the Dutch Ministry of Infrastructure and the Environment, which is implementing the Global Water Programme. In many cases, we are responsible for reconnaissance work such as analysis and definition of possible solutions. Here, the focus is often on using the natural systems including the subsurface for capturing and storing rainfall.