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IMproving PRedictions and management of hydrological EXtremes

Periodic Reporting for period 3 - IMPREX (IMproving PRedictions and management of hydrological EXtremes)

Reporting period: 2018-10-01 to 2019-09-30

Present day water management in many sectors has to be able to cope with extreme hydrological conditions. In addition, the impacts of global warming on water resources have become a matter of grave concern to water resource managers and decision-makers. The limited predictability of these extremes at sufficiently long lead times results in considerable social vulnerability, also in light of the imminent increase in frequency and severity of extreme events in the future.
“Learn from today to anticipate the future” has been a leading principle throughout the IMPREX preparation and execution phase. Scientific developments covered basic understanding of drivers and processes, advanced model development, tuning and evaluation of existing practice-oriented tools and approaches, and assessment of (cross)sectoral risks and policy implications. We have worked with a wide range of stakeholders, many of them being affiliated with project partners in earlier professional interactions. And in dedicated case studies tools and procedures were explored to optimize the stakeholder decision processes. In addition, (seasonal) forecasts and climate information were developed that were tailored to their environment.
A selection of scientific outcome of IMPREX comprises:
• Contributions to the development of both global and regional NWP systems have been achieved by leading institutes in the field. An improved postprocessing of the GLOSEA5 seasonal forecasting system assisted drought risk outlooks in the Jucar and Segura basins in Spain. Data assimilation in the regional NWP system Harmonie have allowed including new snow information for hydropower forecasts.
• A “surrogate warming” experiment has demonstrated the applicability of high-resolution convection resolving regional climate models for future climate applications. For urban flood risk assessment in Italy and exploring climate change impacts on drinking water production in Spain this provided an alternative to the use of an expensive large ensemble.
• A number of new concepts has been developed. A thorough evaluation of the role of compound events for the water management of regional water authorities has been carried out in the Netherlands, leading to guidance on altered risk assessment procedures for regional water safety and/or water resources policies. A revised water resource allocation scheme based on current and future risk of damage has been designed, altering the risk assessment procedures for water allocation problems in the Netherlands and Spain.
Developments of sectoral applications include:
• A novel probabilistic flood damage model allows the assessment of flood risk using a much better picture of the actual damage of floods.
• A systematic evaluation of the economic value of using perfect or operational forecasts for hydropower operation has been carried out, showing that an economic gain of a few percent of annual turnover is achievable, depending on the local conditions.
• A pre-operational probabilistic forecasting system has been launched to support decision making in the Rhine navigation sector. Forecasts extend from the short range to the monthly time scale, actively used by various stakeholders in the area. A systematic evaluation of the forecast value for different operational strategies is enabled by the development of a navigation cost structure model.
• Short-range forecasts of turbidity of raw water reduced cost of chemical treatments by a Spanish drinking water treatment plant (DWTP). Also a methodology to control the risk of algae growth to reduce health risks, and a series of climate change projections focused on future droughts and algae development were tailored to DWTPs.
• Drought indices are defined that express the socio-economic impacts rather than hydro-meteorological aspects for selected basins in Spain, Italy and Spain. The FRIDA tool uses machine learning to calibrate impact-oriented drought conditions to local basin characteristics. An updated water accounting system improves comparability of water resource characteristics of large catchments across Europe, by standardizing water input, output and consumption metrics.
• A novel mapping of the sensitivity of European economy to remote climate effects reveals influential dependence of European well-being and economy on global climate features. Tracing the water footprint of food production climatic hotspots have been identified.
Sector-specific applications and case study examples show that the knowledge developed by the project partners supports risk management and adaptation planning, not only at regional but also at national and European level. Sector-specific impacts include:
• Increased interpretation and use of seasonal forecasts in Jucar and Segura basins;
• Improved flood forecasting due to innovations in hydro-meteorological model equipment and application of flood damage models;
• Significant uptake of (sub)seasonal forecasts in the inland water transport sector;
• Enhanced uptake of near-term probabilistic forecasts in the water treatment sector;
• Mapping potential value gain of using (seasonal) forecasts by the hydropower sector;
• Survey of current and future climatic influence on virtual water trade has exposed vulnerabilities of various food commodities in Europe.
In addition, IMPREX has generated an incremental contribution to the quality of forecasting systems, climate services and science-practice and science-policy interactions. Raised awareness of these factors will improve future science-practice interactions.

Stakeholder interaction, forecast system development, climate change impact analysis are all activities that take a long time to mature. For some specific applications IMPREX can present a number of success stories:
• IMPREX has engaged both public and private partner organizations and end-users to maximize the contribution of tailored information to their benefits. Case study evaluations by the contributing SMEs (Future Water, HKV and the start-up R2water) has added to their product portfolio, supporting the development of a business model for climate services. The river transport forecasting service initially was developed as prototype, but based on very positive stakeholder feedback and partner BfG has been requested to turn the service into an operational forecasting system.
• The DWTP forecasting and monitoring services developed by CetAqua is exploited by Suez in a large number of DWTPs via the platform HIDROMET.
Successful outreach activities were:
• A coherent analysis of European policies in flood risk and drought management was executed, highlighting the usefulness of IMPREX tools and methodologies for implementation of EU Policy Frameworks on Floods and Droughts at basin level. Policy briefs were produced about different topics related to these policy areas (Deliverable 13.6 and 14.6).
• For each sector, a factsheet was produced with major achievements, tools and user responses on these results. Also factsheets were produced on the contribution of IMPREX to forecasting and projection tools, and novel concepts in water related climate services.
• Further outreach has been spread over different target audiences, and included a wide range of dissemination channels: scientific papers, conference sessions at eg EGU and ECCA, public seminars, press releases, policy advising sessions (e.g. EU Working Group on Floods) and webinars all contributed to the legacy of the project.
Dominant predictability source (SCF:better predictions, IHC:large influence of initial conditions)
Graphical overview of the novel concepts explored in IMPREX.