SHOW CASE B 'FLOOD'

Trans-compartment transport of energy and matter during precipitation and flood extremes

Floods have a large variety of societal impacts that span across space and time and cause economic and environmental consequences (IPCC, 2012). The acceleration in population growth and changes in land-use patterns have increased human vulnerability to floods. Floods affect more people worldwide than any other natural hazard, and their global expected annual loss in the built environment is estimated at US$ 104 billion (GAR, 2015). For Germany, flooding has caused 50% of all economic losses due to natural hazards during the last 6 decades. Moreover, the flood in the Elbe and Danube river basins in 2002 was so far the most costly natural hazard for Germany. According to recent projections, climate change will be associated with a significant increase in frequency and intensity of floods due to extreme rainfall with so far unforeseeable consequences and feedbacks (Alfieri et al., 2016). These changes need to be considered when assessing future flooding risks, and respective prognostic tools need to be developed.

Currently, extreme precipitation and related river flooding is often investigated within the respective compartments, only considering compartment-related measurements, although flooding is a cross-compartment phenomenon. This focus on compartments causes significant knowledge gaps with respect to process understanding and prognoses. During flood events cascading effects lead to complex, and little understood, event-chains that affect multiple compartments in an unknown time-delay manner.

The overall scientific aim of Show Case B is to better understand and quantify the coupled processes during and after flood events, including cascading short-term and long-term effects on the terrestrial and coastal systems.