Delta Life 9

More reports on www.deltares.nl Storing rainwater in the winter for use in the summer: tests have already demonstrated that it is technically possible to store excess rainfall in underground reservoirs. That is fortunate because fresh water is scarce in a delta with large amounts of salt water. The shortages of fresh water in the region of The Hague, Westland and Rotterdam is a cause for concern in the summer for farmers, water authorities and drinking water companies. Another way of increasing reserves of fresh water in addition to storing it in reservoirs involves desalinating brackish groundwater. A new source of water is created that makes the water fresh in, for example, dune areas and deep polders. Deltares was asked by, among others, the province of Zuid-Holland, Dunea and the Delfland water authority to conduct a feasibility study with KWR and Arcadis. SAVING ENERGY  WITH GROUNDWATER Sixty percent of annual electricity production in Abu Dhabi, United Arab Emirates, is used for cooling. Which is hardly surprising when you think that the average temperature is 37°C during the hottest months of the year. But considerable emissions of greenhouse gases are the result. In the search for ways to make this process greener, Deltares researchers are advocating a combination of a district cooling system and energy storage in the groundwater (aquifer thermal energy storage). The system involves cooling buildings using an underground network of pipes that ef- fectively works like air conditioning. During the winter, the stored ground- water cools down again. The cooled groundwater can then be used to cut the energy consumption of the cooling system. This idea will allow Abu Dhabi to save about fifty percent on energy consumption by comparison with local air-conditioning systems. E070619a heat pump ATES heat exchanger SPONGE CAPACITY OF MEXICO CITY Mexico City has floods in the summer and water shortages in the winter. Together with design consultants De Urbanisten, Deltares developed a strategic water approach that can be used on a relatively small scale. The strategy revolves around retaining, slowing down, storing and reusing water, and only discharging it where necessary. This enhances the sponge capacity of the city and creates the conditions to store water naturally in the subsurface. The approach also prevents further land subsidence and creates more green in the city which, in turn, provides more cooling. The city was split up into six zones, each with its own water strategy and a catalogue with solutions for water management. Coastal erosion and impaired water quality are threatening the spectacular coastline of Aruba, which is an impor- tant source of income for the island. The Ministry of Infrastructure and the Aruba Tourism Authority issued instructions for an investigation of the problems affecting the coastline and called for solutions. Deltares is working with the engineering firmWitteveen+Bos to determine why the coast is eroding and how the process can be slowed down. The study also includes looking at ways to improve water quality. Where possible, natural solutions are being conside- red in order to minimise the impact on the locality. PRESERVING THE ARUBA COASTLINE STORING FRESH WATER UNDERGROUND