Deltalife 13

5 Safeguarding freshwater supplies for agriculture in Vietnam The densely populated Mekong delta faces numerous water- related challenges such as freshwater supplies, drought, land subsidence and alarming forecasts of sea level rise. The Netherlands Enterprise Agency (RVO) asked Deltares and other organisations including Wageningen University & Research and a number of local parties to look at how tried and tested technologies can help to deliver adequate supplies of fresh water for this important agricultural region. One of those technologies is the storage of water underground. Excess rainfall is stored temporarily in the wet season. This water is used to irrigate the land during the dry season when there is not enough water for the crops. This approach (Aquifer Recharge and Storage), which has been tested in the coastal area of the Netherlands and Flanders, also results in less salinisation of groundwater and less land subsidence. And local authorities, professionals and communities are being given training. In this way, farmers learn to improve their access to fresh water so that they can adapt to changing climate conditions and protect their income and our food supplies. Monitoring new offshore foundation technology A new method has been tested in the port of Rotterdam for installing the foundations of offshore wind turbines. This new approach, the Gentle Driving of Piles (GDP), uses low- and high-frequency vibrations at the same time. That makes it easier to install monopiles while reducing noise levels. Field trials were conducted on Maasvlakte 2 to compare the new GDP method with the usual techniques such as pile- driving and vibration. Sensors on the pile and in the seabed recorded large amounts of data and measured the lateral load capacity. Researchers were able to use these data to refine the prediction models used by the offshore wind industry to estimate the impact of installation operations and the measures required. The first test results are promising and the initiators - which include Delft University of Technology, Deltares and ten industrial partners - hope the innovation will soon be ready for the first offshore pilot tests.