The Central European Rivers are located in the heart of Europe covering several states as well as a wide range of runoff regimes and climate characteristics from mountainous to maritime to continental.
The main challenges and tasks in this densely populated area are to reduce vulnerability due to hydrological extremes, especially floods and droughts. The flood of 2013, for example, claimed several lives and caused monetary damages of billions of euros. Numerous transport connections (roads, railways, rivers) were interrupted for days. In addition, water scarcity from droughts is a severe problem, especially against the backdrop of future climate change and socio-economic developments.
Therefore, a large number of stakeholders ranging from governmental and international organisations, insurance companies, forecasting centres, private companies, and lobby associations are involved in this case study.
Within this case study, we tackled numerous topics: floods, droughts, fresh water allocation and navigation. Amongst others, we improved the information on the expected flood extent before and during future floods as well as the expected damage. In that context, the spatial transferability of flood damage models was evaluated and thus contributed to a European approach/method to flood damage assessment. Also, the development of a risk-based methodology to support fresh water management was in the focus. Last, but not least, new forecast methods and related products were developed e.g. for navigational users along the main European waterways.
With the River Rhine being one of the sectoral integration areas, the Central European River case study was a vital element of IMPREX.
This case study demonstrated the usability and the added value of developments/improvements suggested by IMPREX. We helped to quantify the improvements in terms understandable and relevant criteria/indices for the different stakeholders.
Moreover, as the area covers different runoff regimes, climate characteristics and socio-economic structures, this case study facilitated and proved the transferability of the methods to other regions which may even be outside of Europe.
Tools and models
One of the main instruments in the Central European Rivers case study was improved hydrological models (e.g. HBV, LARSIM…) and related pre- and post-processing techniques developed mainly in IMPREX Work Package 4 (Improved predictability of hydrological extremes).
For some aspects, the hydrological models were coupled to hydrodynamic models (e.g. Sobek, Delft-3D) in order to calculate water-levels at relevant points/gauges as well as inundation areas. A weather generator needed to be applied in order to produce extreme events (extremely wet as well as extremely dry).
In addition to these more physically-based tools, statistical models, like Bayesian networks or risk analysis methods, were applied in order to evaluate cost-effectiveness of measures, forecast products and decisions.
The results can be integrated in the River Basin Hydrological Plan and the Drought Management Plans if the seasonal forecast is good enough to reduce the uncertainty existing in the current management tools (where dynamic seasonal forecasts are not used). Currently, the results haven’t been convincing enough for it to be implemented in decision-making as it may introduce a new source of uncertainty in the currently used methodologies for drought planning and management.
Read more on this case study.
Photos courtesy of BfG
To trap the full potential of inland waterway transport, the importance of hydrological forecasts from the short-term up to the seasonal scale will increase in the future.