Clemens Strehl (Germany) 1; Fabian Vollmer (Germany) 1; Andreas Hein (Germany) 1; Juliane Koti (Germany) 1; Marc Scheibel (Germany) 2; Paula Lorza (Germany) 2; Daniel Heinenberg (Germany) 2; Robert Mittelstädt (Germany) 3; Eduard Interwies (Germany) 4; Stefan Görlitz (Germany) 4
1 - IWW Rheinisch-Westfälisches Institut für Wasserforschung gGmbH; 2 - Wupperverband; 3 - Hydrotec Ingenieurgesellschaft für Wasser und Umwelt mbH; 4 - InterSus - Sustainability Services
Growing risk of flooding is a global threat. Their expected aggravation by climate change is scientific consensus. Still there is a demand for smart adaptation strategies, methods to define best fitting measures for risk reduction and their case study application to collect evidence. The BINGO PROJECT covers research on methods to manage and treat risks from hydrological weather extremes, including the application of the risk management process in case studies.
The German BINGO research-site studies fluvial flood risks at the Mirke creek in the urban area of the city Wuppertal. The municipality and the regional water board (Wupperverband) aim to implement measures to reduce urban flood risk around the creek. Most recently (May/June 2018) flood events caused severe tangible damage, empathizing urgency of stakeholders to act. The aim of the current work at the research site is to establish and test a method to select cost-effective risk reduction measures. This includes a risk assessment, prioritizing so-called spatial hotspots by their different magnitude of expected damage from future floods. A scenario approach is followed to estimate potential aggravation of the flood risk level under near-future climate change. The scenarios used build on simulations of a regional climate model (MiKlip), which delivers decadal predictions of weather patterns. In terms of risk treatment, alternative measures for each hotspot will be evaluated. This evaluation will cover several key indicators per measure, like:
- monetary benefits (reduction of expected damage, i.e. saved damage costs to properties),
- non-monetary benefits (reduced inhabitants at risk and reduced critical infrastructures like kindergartens endangered by flood water).
All measures will be ranked by costs in relation to their benefits to take action where it is most needed at first and to use financial resources efficiently. In addition, the case studies approach integrates cooperative decision making of stakeholders involved. A customized approach, in dependence of the analytical hierarchy method, was used to reach consensus in weighting the importance of different non-monetary risk reduction goals.
The expected result of the case is a better informed risk management by the involved stakeholders. The planned outcome is a list, prioritizing which measures to implement at which hotspot, ordered by their cost-effectiveness. Climate change’s uncertainty is dealt with using not one but a range of possible climate change scenarios for calculations. The method developed and tested may serve as pattern to other cases in the future, facing similar risks and adaptation needs.