The 2019 John Dalton Medal is awarded to Günter Blöschl for pioneering major advances in hydrological predictions, including advances in flood estimations, by linking patterns and processes across small catchments to large regional scales.
Günter Blöschl has advanced the understanding and prediction of hydrologic responses to climate forcing by pioneering a diagnostic approach of investigating spatial patterns to reveal underlying relationships between precipitation and landscape. Through this approach, he has connected hydrologic process descriptions across scales, leading to more generalisable models and model predictions. Thus, Blöschl’s work has contributed to a paradigm shift in catchment hydrology moving from a reductionist paradigm that relied on aggregating small-scale process descriptions to build catchment scale models that can be tested against measured runoff. He used this novel approach in an arid region (Australia) by exploiting soil moisture patterns at the hillslope and catchment scales to learn about runoff processes and the wetness and dryness states of catchments. He determined how dominant flow paths change from vertical to horizontal with increasing soil moisture, and used that insight to improve the internal consistency of distributed models. Then, Blöschl designed a comprehensive study of interacting landscape processes in the Hydrological Open Air Laboratory which he established in Austria. Through this continuing work, he discovered diverse patterns of runoff-generation processes and their coupling with erosional and biogeochemical processes.
Blöschl defined the theoretical concepts behind scaling and provided a new framework to interpret heterogeneity and variability and their implications for conceptualisation of hydrologic processes. As part of leading the Prediction in Ungauged Basins initiative, he improved regional runoff predictions through a new paradigm of co-evolving landscape features containing spatially organised patterns. Blöschl’s research thereby invigorated regional hydrology by integrating process understanding into a field that had emphasised statistical methods. For example, he introduced a flood process typology, such as rain-on-snow floods, guided by the spatial pattern of their drivers.
Blöschl translated this research across scales to advancing flood estimation practice in Europe and elsewhere. For example, he devised a new conceptual framework that combined local flood data with causal information on flood processes and spatial patterns of regional flooding, which has now been adopted internationally. He then implemented this approach across Austria for flood risk management purposes.
Blöschl has contributed to the international hydrologic and geoscience communities in a leadership role in several important organisations. His contributions and discoveries have had a huge impact on hydrology, in terms of improved process understanding and predictions. He has not only been a phenomenal researcher, but also a visionary leader of the hydrology and geoscience communities.