Work package 5
Work Package 5: Improved impact assessment
This workpackage is a close cooperation of partners in all the subprojects, de vided in three main activity clusters. In the first activity three knowledge institutes from Belgium, Germany and the Netherlands will work closely together. In the second activity KNMI and RWS will invite meteorological institutes in Belgium, Germany and France for reviews. All water managers in the EMR region will be invited to the workshops to provide feedback. The third activity is based on close cooperation between BE-NL as the Common Meuse is the border between both countries.
Flood damage: comparisons, data and methods
Water management organizations design and build flood risk reduction measures. The optimal sizing and prioritization of these relies to some extent on (semi-)quantitative impact evaluation methods. This poses a number of challenges to be tackled and there are opportunities to be seized. 1)The approaches currently used across the Euregio differ widely. Sharing information and experience on current practice in the Euregio regions gives a unique opportunity for learning from each other.
A systematic analysis of observed impacts in regions affected during the 2021 flash flood is required. Academic partners from BE, NL and DE will jointly analysis, document and interpret the observed damages. Estimating flood impact is instrumental in guiding the design and prioritization of flood risk reduction measures. However, current knowledge remains limited as regards the optimal structure of damage models and the calibration of their key parameters. The flood event gives the possibility to gain new knowledge which will improve current impact models and tools.
As a result a report will be made with a list of identified public organizations performing flood damage analysis, description of methods used for flood damage analysis in the three EMR countries and a discussion of advantages and disadvantages of the different methods.
A report with an English Questionnaire of +/- 50 questions on flood impact data explanatory variables related to the vulnerability (such as building characteristics, precautionary measures) and the danger (such as flooding depth, velocity, duration)
The target group will be composed of victims of the flood of July 2021, i.e. inhabitants or house owners in the flooded valleys. The target group will include at least 70 respondents in each country (200+ in total), carefully selected to ensure representativity of a broad range of socio-economic profile, level of exposure, and extent of damage.
Synthesis report on improvement flood estimation methods, containing at least content on context and motivation, data, methods, results, discussion and conclusion.
There will also be a webinar for the research outcomes to stakeholders
Meteorological information and rainfall-runoff modelling
The 2021 summer floods were more extreme than have been registered in the last 100 years. It is very difficult to derive an accurate climatology of extreme events, as there are only two extreme summer events (i.e., 1980 and 2021) in the observational dataset.
Instead of using the observations (which are only ~65 years in length) we make use of synthetic data sets that are generated by state-of-the-are weather- and climate models.
Report on extreme precipitation events in the Meuse,containing at least a description of the synthetic datasets, statistical method and discharge model, a table with estimated return values for 1, 10, 100 and 1000 year return periods for the Meuse basin and the tributaries and a simulation of 80,000 years of daily weather with the weather generator based on the synthetic data, and a table with estimated return values for 10,000 and 100,000 year return periods for the Meuse basin and the tributaries.
A report on simulated extreme flood events, with Information about the model , improvements to the model and feedback from partners, results from modelling flood events, based on historical events and synthetic events and an overview of conclusions and literature.
Ecological and morpholocial impact assessments.
The 2021 summer flood strongly impacted the river bed of the Common Meuse locally due to significant erosion and sedimentation. High flow velocities have scoured the river bottom resulting in large sand depositions in the nearby floodplain.
The erosion problems from the flood were most pronounced in the Common Meuse. This river is characterised by the presence of easily erodible sand layers directly underneath. During the flood, the sand layers became exposed and deep scour holes developed (up to 16m). This caused substantial damage to ferry landings, pipelines and dike stability.
Report ecological impact assessment Meuse region with special focus on the Common Meuse. The report will contain a description and comparison of data and methods for ecological parameters, analysis of effects and changes due to the flood in terrestrial and aquatic vegetation, distribution of key plant and animal species and invasive plant species and recommendations for nature and water managers.
A report about the stability of the river bed of the Common Meuse containing at least a description of data (collection) and methods used, including literature, discussion and conclusions on sediment mobility, on sediment input, with a general conclusion on the stability of the river bed of the Common Meuse.
Effects of vegetation on flood risk
A DSS-map of the Common Meuse makes the zones spatially explicit where there are opportunities for high-quality naturalness in combination with flood protection. This management support tool is based on the combination of existing numerical and ecological model results, monitoring data and legal boundary conditions on Belgian and Dutch side.
Report on vegetation in the flood plain Common Meuse withan overview of the impact of natural vegetation and of crops on high water levels using past research and new research, determining indicators for the discussion between flood risk managers and managers of natural areas of the flood plain and providing a methodology for discussions between the water managers and the managers of the natural areas.
Report on DDS prototype on result map on Common Meuse, with a description of the used monitoring data, models and targets for river restoration, nature conservation and flood protection. A description of design process Prototype of a decision support system tool and recommendations on future use of DSS maps.
Assessment of the flood risk on the Common Meuse, based on the flood of July 2021.
In 2020, the Flemish-Dutch bilateral Meuse commission VNBM ordered an assessment of flood risk protection levels at that moment, since the program of flood protection along the Common Meuse had been finalized. This assessment has been delivered in 2021 and it gives an insight in remaining bottlenecks and risks, and recommendations for solutions. The flood of July 2021 was in many ways exceptional.
The river managers now want to examine the flood safety again, with the data of the flood event of July 2021 as it occurred, instead of using the standard parameters in the models. Are there big differences with the former, theoretical assessment?
A report on flood risk Common Meuse based on data July 2021 with a description of the real data of the flood 2021 event, assessment of the bottlenecks, constraints in the river system and risks of flood safety and recommendations for solutions.