Our civil engineering student Sacha Geertman finished her BSc thesis on the topic of 'Climate adaptive outdoor space measures dealing with waterlogging'. She modeled the impacts of 8 different measures for the same urban area, showing widely varying results when it comes to total water storage vs. time before streets are accessible. The next future step is to look at the impacts of combining measures for optimum disaster prevention. The abstract is below, and the repository link to download the full thesis is here.
Abstract
With ongoing climate change, urban areas in the Netherlands increasingly face extreme precipitation events that cause waterlogging. To mitigate these impacts, municipalities must implement adaptation measures. This research aims to identify the most suitable measures for Dutch urban areas to mitigate the impacts of extreme precipitation. D-Hydro, a simulation model, was used to assess the performance of the measures for a case study in Duiven for an 80mm/hr rainfall event. First, a literature study and expert consultation provided an overview of existing adaption measures, their benefits and limitations. Secondly, assessment criteria and modelling methods were determined through literature and expert consultations. Thirdly, seven measures were simulated for the case study: de-paving, ditches, infiltration crates, green roofs, permeable paving, sewer improvement and wadis. These were evaluated based on: water depth on the road, time until roads are accessible, total infiltration, water flow towards the nearby neighbourhood, water level rise in the nearby waterway, costs and space. Results showed that wadis performed best overall, but require a high investment and a large area. Ditches also performed well on most criteria and are also cost- and space-effective. Permeable paving and de-paving are cost-effective measures, but are less effective in enhancing the infiltration. Due to required technologies, infiltration crates, sewer improvement and green roofs have relatively high costs but do not require outdoor space. From this, it was concluded that no single measure is the best option in every situation and that the suitability and effectiveness of a measure is highly dependent on location specific characteristics and the client’s priorities. Nevertheless, the qualitative scores and the simulation provide a first insight into the possibilities and considerations for each adaptation measure. Through this way, a client can make a more targeted decision about the adaptation measure that is to be implemented.
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