Early recognition of potential drought impacts

In recent years the extreme droughts in large areas of Europe have shown that seasonal forecasts of drought phases are critical. Only then can timely measures be taken to reduce the negative impacts on ecosystems, waterborne transportation, agriculture and power generation. Together with a team from the Dutch universities of Wageningen and Utrecht, Dr. Veit Blauhut from the Chair of Environmental Hydrological Systems at the University of Freiburg has developed the basis for a new forecasting system. With this system, timely assertions can be made about the occurrence and potential effects of droughts. The researchers presented their results in the journal Nature Communications.

In their study, the scientists succeeded in predicting droughts and their ensuing impact on inland navigation, public water supply, water quality and ecosystems two to four months in advance. The team based their research on the European Drought Impact Inventory (EDII) database, which was developed in Freiburg. The database collects reports on how past drought events affected different regions and sectors. The researchers then used machine learning techniques to link the effects recorded for each month to currently monitored drought indices such as the Standardized Precipitation Index (SPI). In this way, they were able to establish a link between the impact on a given area and the drought indices for each European region for which sufficient data are available in the EDII.

In a second step, the scientists analyzed the seasonal forecasts of surface runoff and precipitation available in the archive of the European Centre for Medium-Range Weather Forecasts (ECMWF) for each month from 1990 to 2017. These forecasts can usually be made seven months in advance. The researchers then compared the analyzed correlations with the historical seasonal forecasts and realized that their method would enable them to make reliable statements on how the expected precipitation and runoff will affect different areas in the following at least two to four months.

In order to mitigate the long-term consequences of drought, it is essential to improve our understanding of past events, in particular the causes of damage. The researchers are thus calling for the development of a drought directive to be placed on the political agenda, which commits to investigating both drought risk and drought management: “In this framework, the data on drought effects that are necessary for impact early warning systems could also be compiled comprehensively,” explains the Freiburg hydrologist Blauhut. “It is imperative that drought be given higher priority on the research agendas of the individual countries and the European Union.”

The team conducted its study within the framework of the European Union-funded Horizon 2020 project ANYWHERE and the drought research project DRIeR, funded by the Water Research Network of the Ministry of Science, Research and the Arts of Baden-Württemberg. The aim of these projects is to improve emergency management and response to extreme weather and climate events.

Original publication:
Sutanto, S.J., Van der Weert, M., Wanders, N., Blauhut, V. und Van Lanen, H.A.J. (2019): Moving from drought hazard to impact forecasts. In: Nature Communications. DOI: 10.1038/s41467-019-12840-z

For more information about the drought research project DRleR