Overview of the results & their exploitation and dissemination. Selection of highlights of project outcomes and societal impacts.

Moving toward high‐resolution gridded hydrologic models asks for novel parametrization approaches. A high‐resolution conceptual hydrologic model (wflow_sbm) was parameterized for the Rhine basin in Europe based on point‐scale (pedo)transfer functions, without further calibration of effective model parameters on discharge. Parameters were estimated on the data resolution, followed by upscaling of parameter fields to the model resolution. The method was tested using a 6‐hourly time step at four model resolutions (1.2, 2.4, 3.6, and 4.8 km), followed by a validation with discharge observations and a comparison with actual evapotranspiration (ETact) estimates from an independent model (DMET Land Surface Analysis Satellite Application Facility). Additionally, the scalability of parameter fields and simulated fluxes was tested. Validation of simulated discharges yielded Kling‐Gupta Efficiency (KGE) values ranging from 0.6 to 0.9, except for the Alps where a volume bias caused lower performance. Catchment‐averaged temporal ETact dynamics were comparable with independent ET estimates (KGE ≈ 0.7), although wflow_sbm model simulations were on average 115 mm yr−1 higher. Spatially, the two models were less in agreement (SPAEF = 0.10), especially around the Rhine valley. Consistent parameter fields were obtained, and by running the model at the different resolutions, preserved ETact fluxes were found across the scales. For recharge, fluxes were less consistent with relative errors around 30% for regions with high drainage densities. However, catchment‐averaged fluxes were better preserved. Routed discharge in headwaters was not consistent across scales, although simulations for the main Rhine River were. Better processing (scale independent) of the river and drainage network may overcome this issue.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2019WR026807

German minister of transportation officially started the operational 10-day water level forecast for the river Rhine developed in the context of IMPREX.

PRESS RELEASE (German)

https://www.bafg.de/DE/Service/presse/2019_12_04_pm.pdf?__blob=publicationFile

10-day water level forecasts for selected Rhine levels

https://www.elwis.de/DE/Service/10-Tages-Wasserstandsvorhersage-Rhein/Rheinpegel-node.html

This brochure presents an overview of new meteo- rological models, hydrological forecasting tech- niques, management approaches and innovative concepts, developed and applied as part of the IMPREX project. Furthermore, sector-specific fact-

sheets outline innovative solutions developed and applied within different sectors and addressed within the framework of the project: flood mana- gement, hydropower, water transport, urban water supply, management of droughts with a focus on the agricultural sector, and global water economy relations. Case studies illustrate how, within the IM- PREX project, climate information was customized to meet the different stakeholders’ needs, providing guidance on current practices as well as innova- tive tools. Three policy briefs and one position pa- per, translating promising tools and relevant topics and approaches to the relevant target groups, are presented here. Selected topics are (1) compound events with regard to the implementation of the EU Flood Directive, (2) probabilistic approaches to improved flood risk assessment and management under consideration of uncertainties and (3) suc- cessful implementation of preventive drought risk management in Europe. Additionally, a position pa- per presents lessons learned with a view to possible steps towards action-oriented outcomes of applied research and climate services for the water sector.

• The European Commission report on the implementation of the Water Framework Directive (2019) has shown once more: drought risk management is still not where it should be. Still, only few Member States have either set-up drought risk management plans or have otherwise covered the topic extensively within river basin management plans. At the same time, climate change increases the pressure to act on making Europe more resilient to droughts and water scarcity.

• Appropriate acknowledgement of the importance of preventive drought risk management by Member States and the European Commission (EC) is needed, paired with respective concrete steps, such as:

  • On EU-level: setting up a firm policy framework for drought risk management, providing improved guidance and support for its implementation, and paying sufficient attention to local features in assessing drought risk across Europe

  • At Member State level: increasing capacity to adequately respond to current and future drought risk, e.g. by enhancing the drought monitoring and forecasting infrastructure at basin level, to, among other, monitor and develop basin-specific drought indices that can complement regional stakeholder assessments; or by improving anticipatory operational drought risk management

• The research project IMPREX has developed innovative tools and approaches that support improved drought risk management at various administrative levels.

This paper presents lessons learned on successful science-policy, science-practice and science-science interfaces for increased impact of research and innovation. The paper provides recommendations on research policy, program design and project organization for more fruitful European research.

New hydro-meteorological forecast and risk management products by IMPREX improve the operational efficiency of European flood management and help mitigate the vulnerability to hydro-meteorological extremes.

Less than half a century ago, skilful weather forecasting beyond a few days ahead was deemed fundamentally impossible. The atmospheric system was assumed to be too chaotic, the observations too few, the computing power insufficient, and the process understanding too limited. In contrast, we currently pick the fruits of high-quality forecasts of hurricanes hitting coastal residents, timely warnings for elevated flood risks, and useful outlooks to manage agricultural practices or hydropower lake storage dynamics. This has become possible by acknowledging the need to join forces between observational experts, model developers and society-oriented forecast providers. And by accepting the need to take a long breath to build, upgrade, refine, couple, tune, tailor, test and adjust the complex forecasting systems. These systems produce today forecasts with high detail for a few days ahead to outlooks of climatic conditions at longer lead times.

The progress in the business of hydrometeorological forecasting and climate outlooks has been achieved by combining dedicated long-term resources resident in public dedicated hydrometeorological services, with focused project activities devoted to specialized components of the forecasting systems. IMPREX is happy to have made an incremental contribution to some of Europe’s best hydrometeorological forecasting and climate projection systems. It has focused on crucial elements used in operational and policy-oriented decision support systems of institutions in the European water sector, while successfully embedding its findings in the development cycles of influential forecasting agencies.

IMPREX has contributed to global and limited area Numerical Weather Prediction (NWP) systems operated by ECMWF, the UK MetOffice and members of the Harmonie NWP consortium. It has worked on coupled hydrology/meteorology forecasting systems used for flood risk warnings, water allocation and seasonal outlooks operated by the European Copernicus Climate Change Service. It has also worked on creating enhanced detail in climate change projections by testing new experimental designs involving high-resolution convection-permitting climate models operated by the Harmonie NWP consortium and the UK MetOffice.

The development of adequate climate services for the water sector requires an effective combination of a robust scientific base and a client-oriented focus on the development of innovative and tailor-made tools and approaches.

New IMPREX approaches increase operational efficiency of the hydropower sector by demonstrating the economic gains of hydrometeorological forecasting combined with efficient management approaches.