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Future Area of Conflict: Water Use How is Drought Perceived?

High temperatures, low levels of precipitation, and intense sunshine—these are factors that can be expressed in numbers. But what about the victims of drought, like government agencies, foresters, and farmers: How do they perceive drought? What water resources do they use or manage? Do they have specific indicators for drought? For the first time ever, scientists have conducted a survey in Baden-Württemberg to find out the answers to these questions. The hydrologists Michael Stölzle and Kerstin Stahl of the University of Freiburg aim to use the results to forge a link between research and practice and help out the victims.




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Ein gewohntes Bild in Freiburg: Von den Wassermengen der Dreisam ist im Sommer nicht viel zu sehen. Foto: Universität Freiburg


The goal was to identify indicators for drought. To achieve this, the hydrologists Michael Stölzle and Dr. Kerstin Stahl conducted a survey to find out how actors in various sectors are impacted by drought and heat. They asked government agencies, foresters, and farmers as well as associations and officials in the water industry to participate in the survey.

The researchers succeeded in determining the times at which drought poses a particular threat for all of the sectors as well as in identifying specific indicators for various areas and sectors. Stölzle and Stahl were led to the conclusion that the recent increase in extreme weather events like heat waves, droughts, and storms is perceived as a threat in all sectors. In the future, the proliferation of droughts will lead increasingly to conflicts between the various actors. Find out more about the survey in the interview and gallery below. 

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 Dr. Kerstin Stahl is a research assistant and lecturer at the Institute of Hydrology of the University of Freiburg. She earned her doctorate in 2001 with a dissertation on hydrological droughts in Europe. She then collaborated on research projects at various universities, for instance on global water conflicts at Oregon State University (2001–2003) and on the impact of climate and land-use change on the regional hydroclimatology and hydrology, particularly under low-flow conditions, at the University of British Columbia, Canada (2003–2007), the University of Oslo, Norway (2007–2010), and the University of Freiburg. She is currently working with colleagues in Zurich on the project “DROUGHT-CH: Early Recognition of Critical Drought and Low-Flow Conditions in Switzerland,” funded by the Swiss National Science Foundation. Starting in October 2011 she will supervise the work package “Drought-Sensitive Areas in Europe: Impacts, Vulnerabilities, and Risks,” part of a new EU project on drought management (DROUGHT-R&SPI: Fostering European Drought Research and Science-Policy Interfacing).
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Dipl.-Hydrologe Michael Stölzle
Michael Stölzle completed his Diplom degree in hydrology at the University of Freiburg in 2008 with a thesis on “Changes in the Frequency of Weather Situations and the Isotope Composition of Precipitation in Germany.” In the following year he participated in the modeling of sediment dynamics at the mouth of the Argen River on Lake Constance. He has served as a research assistant at the Institute of Hydrology since 2010, where he was initially involved in a joint start-up project with the Meteorological Institute on “Heat and Drought in the Upper Rhine Region,” funded by the Baden-Württemberg Ministry of Science, Culture, and the Arts. In 2011 Stölzle began work on a doctoral degree under Prof. Dr. Markus Weiler at the Institute of Hydrology. The title of his dissertation project is “Climate Sensitivity and Vulnerability of Waterways in Connection with Low-Flow Drainage.”



Surprising Science: Why was it important to conduct a survey on indicators for drought?

Stahl and Stölzle: We have both been involved in research on drought for a long time and have observed that there is a discrepancy in how droughts are perceived between science and research and the businesses and agencies actually affected by them. We scientists often calculate indices on precipitation or water quantities, but it was time to tackle the question of how these findings can be put to practical use.

Surprising Science: Hasn’t this been done before in Germany?

Stahl and Stölzle:
Drought has been an issue for quite some time in eastern Germany, but in Baden-Württemberg more emphasis has been placed on flood control measures. Here we’re just beginning to tackle the critical question of what to do about drought. This has long been an important topic for countries in southern Europe. Starting this fall, the EU project DROUGHT-R&SPI will investigate the risk of drought from a broader perspective.
Surprising Science: What criteria did you use to select the participants in the survey?

Stahl and Stölzle: We limited ourselves to Baden-Württemberg and took into account all regions and sectors that come into contact with drought and nature. Foresters and farmers were invited to take part, for instance, but so were numerous government agencies on the municipal, regional, and state level that deal with environmental topics. We wanted to collect a lot of information from different areas. The size of the agencies and businesses was not the important thing. We are aware that their responses are colored by their subjective perceptions, but they still contain important information.

Surprising Science: How did the participants react to the survey?

Stahl and Stölzle: We received positive feedback, particularly from the government agencies. Drought is currently a hot topic at the district administrative offices. In general, we found that all of the participants were well informed and were already very knowledgeable about the topic of drought. Were there indicators for drought that were named by all of the participants? Yes, there were: a lack of precipitation, dry ground, and a lowering of groundwater levels. 83% rated low levels of precipitation as the main indicator for drought. Factors like high evaporation rates and heat, on the other hand, were cited less often. We see that as an important finding: The actors differentiate between indicators for drought and those for heat.

Surprising Science: Have the participants in the survey noticed a change in the climate?
Stahl and Stölzle: Yes, very much so, particularly with respect to an increase in extreme events such as thunderstorms, cyclones, and forest fires. We also found that at this point in the survey the participants no longer able to concentrate specifically on drought as an extreme event. Rather, they always combined drought with various other extreme events in their accounts.

Surprising Science: Can drought lead to water use conflicts in the future?

Stahl and Stölzle: Conflicts will arise especially as far as rivers and bodies of water are concerned, since these areas are important for hydroelectric power and irrigation. For example, the agricultural sector is reporting longer cultivation phases due to the rise in average temperatures. This means that crops need more water, leading to a decrease in water levels. Rain and groundwater, on the other hand, will not be objects of contention, because these are resources that are less readily accessible. In order to prevent water use conflicts, it is important to bring the various actors—meaning those who use water—together. Surprising Science: Have agencies and businesses changed their practices as a result of the heat wave in the summer of 2003?
Stahl and Stölzle: There were a lot of discussions after 2003, and there is now a heightened sensitivity towards the topic, but very few concrete measures have been taken. Finding out why this is so would involve conducting another survey. In general, it is still questionable as to whether it is necessary and desirable to change practices at all in certain areas. But drought management is an important issue, because droughts are natural events and will thus happen again and again. We need to find solutions—and that means ways of dealing with these events. After all, we can’t prevent them from happening.

Surprising Science: What conclusions do you as scientists draw from your survey?
Stahl and Stölzle: The survey confirmed that scientists need to take into account more variables when confronting this complex issue. It is no longer enough to just analyze precipitation levels and create scientific indices. It has become evident that there is a need for information and an interest in new methods and early-warning systems on the part of the actors at all levels. We hope to have forged an initial link between science and the victims of

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Picture Gallery

dreisam_1_(Uni Freiburg).jpg dreisam_2_(Uni Freiburg).jpg dreisam_4_(Uni Freiburg).jpg    
Dried-out riverbed Dreisam, Freiburg.
Source: Bilderarchiv des Instituts für Hydrologie, Uni Freiburg.
Dried-out riverbed Dreisam, Freiburg.
Source: Bilderarchiv des Instituts für Hydrologie, Uni Freiburg.
Dried-out riverbed Dreisam, Freiburg.
Source: Bilderarchiv des Instituts für Hydrologie, Uni Freiburg.


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