The Netherlands has suffered form three successive dry summers resulting in a lowering of the groundwater table, causing water shortage. Also in the area of Water BoardDe Dommel, locatedwithin the province of Brabant, water shortage is a common problem. This results in water abstraction restrictions for farmers in the crop season every year. With climate change the precipitation pattern in the Netherlands will change, resulting in longer dry periods during summertime. Water Board De Dommel is searching for strategies to decrease this water shortage. These strategies need to be tested for future climate scenarios. This research tests different interventions for two specific areas within De Dommel. These areas differ in land-use, location in the catchment, geo(hydro)logy and infrastructure. This research answers the following research question: How does the groundwater of two different areas within Waterschap De Dommel react to different interventions
to prevent water shortage in long-termfuture scenarios?
To find the answer to this research question a stationary groundwater model (iMOD) is used. In this model
the different interventions are tested with four climate scenarios from the KNMI. These interventions take place in the top layers of the subsoil. Next to these interventions also three abstraction scenarios are modeled, to see the effect of changes in deeper aquifer layers. The interventions are tested with three signals from the model: 1) the head of the first aquifer layer, 2) the water balance for both areas for the first aquifer layer as well as the first four aquifer layers combined and 3) the flow paths. Because models include uncertainties and assumptions, expert judgement is included to test the interventions. The expert judgment is based on historical maps and the location of the interventions. At the end of the research a non-stationary model is used to test the "Brook swamp" intervention. This result is compared to the results of the stationary model of this intervention. The results show that changes in the top layers of the subsoil have almost no effect on the groundwater in the deeper layers for De Pielis area. More downstream in the catchment, at the Landschotse Heide area, this effect is bigger, because of changes in the upstream area. In the top soil layers the groundwater reacts positive for most interventions for both areas resulting in more water availability. Also in the top layers the effect is bigger at the Landschotse Heide area than at De Pielis area. With the non-stationary model results the groundwater reacts more positive to the "Brook swamp" intervention than for the stationary model. A non-stationary model is therefore better to see how the groundwater reacts to seasonal dependent interventions. The groundwater reacts differently per areas as well as per intervention. In both areas the groundwater does react positively to most interventions. For the Landschotse Heide area the groundwater reacts more positive than for De Pielis area. For both areas the "higher water level" and "closed ditches" interventions show the most positive reactions of the groundwater. Based on these results the Water Board is advised to research the effect of enriching the top layer of De Pielis, to see if these top layers can then hold more water. For the Landschotse Heide the Water Board is advised to decide if agriculture or nature is more important in that area, because these cannot coincide, and reach all demands, in the way it is set-up now.