| dc.description.abstract | The changing climate and socioeconomic growth form a threat for the groundwater extraction used for drinking water production in the Netherlands. Periods of severe drought result in quantitative shortages and the increasing human population and increasing surface activities result in a higher drinking water demand, while this also reduces the quality of groundwater. In order to solve this increasing quantitative and qualitative problems for the future, flexibility increasing solutions need to be implemented at the extraction location of the Dutch drinking water production company Vitens. These solutions can aim on increasing the flexibility of the amount of extractable groundwater or result in an increasing flexibility within groundwater quality. In order to be able to describe different solutions, inspiration was gained in 13 interviews with hydrological experts and three inspiration presentations from other knowledge domains. This resulted in multiple concepts that are developed into flexibility increasing solutions using available literature on Google Scholar. These solutions were implemented at two existing extraction locations of Vitens (Manderveen and Vechterweerd) which represent the two archetypes that are of interest (shallow groundwater extraction in a rural environment and riverbank filtration extraction). This implementation is done, to be able to give a quantitative expression of the performance of a solution and its costs. Solutions that fall within the scope of this research are selected using four criteria and after that classified in different classes. These classes are: quantity or quality solutions, internal or external solutions and a final classification is done on the expected future problems (scenario’s for climate change and socioeconomic growth) that individual solution aim to solve. This classification is done, to be able to make a start in developing a toolbox for Vitens in which solutions can be implemented after observing a specific quantity or quality problem at an extraction location of the previously described archetypes. The internal and external class is used to clarify if Vitens is able to implement a solution internally, or if external stakeholders need to be drawn into the implementation process of a solution. After this selection and classification, the different solutions are tested on efficiency by dividing their yearly operations expenses by their yearly performances (€/m3). These efficiencies are ranked in order to draw conclusions on which solution is most and least efficient. These results consist of 12 solutions that form a first investigation of possible solutions for increasing flexibility. The quantitative results of nine solutions can be used as a first rough estimate on performances and costs and to evaluate if this method works for testing the efficiency of the solutions. The results from this thesis research conclude that the external quantity solution of injection of surface water in Natura2000 areas is the most efficient solution for increasing flexibility in groundwater quantity, because it costs 0,01 €/m3 of extra available groundwater. In this method risks are described, but not quantified, due to the unavailability of data. Besides that, the total amount of capital expenditures required for most of the solutions for the total scope of this research (100 years) is also lacking. The inclusion of these risks and costs are a relatively easy win when improving this method of testing efficiency. Besides these two possible improvements to calculate efficiencies more precisely, this method of diving total costs by the total performance of a solution is strongly recommended, because it allows for a comparison of solutions that act on different scales (regional and national). | |
