Delta Life 8

DELTARES, OCTOBER 2017 5 More reports on www.deltares.nl Agricultural phosphate does not affect water quality in the Netherlands as much as has been thought. It has emerged that, because groundwater in many places contains iron, ditches and streams reduce the impact of this fertiliser extremely effectively. That is the conclusion stated by Bas van der Grift in his doctoral dissertation. Phosphate is a problem because excessive levels cause algal bloom. As a result, the oxygen content in the water falls off, and fish and other aquatic animals die. However, phosphate reacts with iron in the groundwater and then settles to the water bed. Due to the artificial nature of the Dutch water system, with its polders and dams, the water flows slowly and the iron phosphate particles are not easily stirred up again. Bas believes that manure policy in the future should take this factor into account. The current manure policy is based on model calculations that do not take the bonding of iron phosphate into account. WATER, CLIMATE AND CONFLICT Water scarcity and flood risks are on the increase, making instability and conflict more likely as well. That is an important conclusion in the document Water, climate and conflict: security risks on the increase? from the Netherlands Environmental Assessment Agency, Deltares and the Clingendael Institute. Adequate and reliable supplies of clean water are crucial for agriculture, homes, industry and the production of energy. Shortages of water to meet these needs can cause tensions between individuals, groups in society or countries. Given the complexity of the problem and the uncertainties about future developments, it is important to look at the relationship between water and conflict from the perspective of different disciplines. A better understanding can help to prevent or control social disruption and conflicts. At the beginning of the Holocene age, about 12,000 years ago, the sea level was sixty metres lower than at present. The North Sea was largely dry. Marc Hijma, who researches sea-level rise at Deltares, is in pursuit of the underlying story. He was on the NIOZ Pelagia research ship last summer to investigate clay and peat layers at various depths. The research is innovative because there is virtually no high-quality information available about the submergence of this area in the past. The expedition is generating new publications, charts and models for the North Sea. The results are geologically and archaeologically interesting, but they are also the source of information about sea- level rise in the future. Marc Hijma has a blog about the research on NIOZ@Sea. DRILLING IN SUBMERGED LAND COASTAL EROSION IN SOUTH KOREA UNDER SCRUTINY understanding of coastal erosion on the Korean east coast in order to establish effective mitigation strategies. Coastal processes are analysed at different levels: from individual storms to the effects over several decades, from an individual beach to an entire coastal area. All these scales are then combined using different modelling techniques. The east coast of South Korea is eroding in several places, posing a threat to the infrastructure and people living along the coast. In recent years, various measures have been taken to combat erosion, such as beach nourishment, breakwaters and groynes, but not always with success. With the Korean Institute for Ocean Science and Technology, Deltares is helping to improve our