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Water repellency is a characteristic of the soil which prevents water from infiltrating into the soil
matrix and is often found in areas that frequently dry out and are not cultivated. The extent of water
repellency is closely related to the organic matter content and soil moisture content of a soil. Organic
matter can increase water repellency by forming hydrophobic particulate matter or as an organic
coating around minerals. Water Repellency can decrease the water use efficiency of plants and
obstruct infiltration, leading to overland flow, increased erosion rates and decreased water retention
abilities. This research aims to establish a broader basis of knowledge on water repellency and its
hydrological consequences and contribute to an increased efficiency in protecting the dunes in the
Netherlands and on Texel specifically. Different soil monoliths have been taken and rain simulations
were performed on these monoliths. The age of the dune soils seems to positively affect both
organic matter content and water repellency. The water repellency appears to significantly increase
the amount of precipitation to run off. However the erosion rates are not fully dependent on the
runoff rates. The second oldest plot showed higher erosion rates as the oldest, despite having similar
runoff rates. Earlier research indicates organic matter can increase the cohesion of a soil. This may
explain the difference in erosion rates, as the oldest soil has a significantly higher organic matter
content. Increasing the amount of rain generally increases the percentage of precipitation which will
run off. Overall it can be stated water repellency is a factor of importance in coastal dune
management. It is especially relevant in areas that are generally not considered to be the most
vulnerable parts of the dune system, the older dunes.