River flow drought

Assessment versions

Published (reviewed and quality assured)

• River flow drought (CLIM 018) - Assessment published Nov 2012

Justification for indicator selection

Lack of water has severe consequences for Europe’s citizens and most economic sectors, including agriculture, energy production and industry. An intense drought throughout the Iberian Peninsula during 2004-05, for example, led to a 40% decline in cereal production, whilst low rainfall in 2006 led to a 30% fall in agricultural production in Lithuania,  with an estimated loss of EUR 200 million. In Slovenia, direct losses attributable to drought in 2003 are estimated to be around EUR 100 million. Furthermore, lack of water detrimentally impacts freshwater ecosystems including vegetation, fish, invertebrates and riparian bird life. Diminished flow also strongly impacts water quality by reducing the ability of a river to dilute pollutants.

Electricity production has already been significantly reduced in various locations in Europe during very warm summers due to limitations of cooling water supply from rivers. Dry periods can also seriously impact the production of hydropower, e.g. in the case of Catalunia where the 2003-2007 drought caused a hydropower reduction of over 40%.

Scientific references:

• . Collins, Robert. 2009. “Water scarcity and drought in the Mediterranean.” EU Change. Douville, H., F. Chauvin, S. Planton, J.-F. Royer, D. Salas-Mélia, and S. Tyteca. 2002. “Sensitivity of the hydrological cycle to increasing amounts of greenhouse gases and aerosols.” Climate Dynamics 20 (1) (November 1): 45–68. doi:10.1007/s00382-002-0259-3. EEA. 2008. Impacts of Europe’s changing climate - 2008 indicator-based assessment. Joint EEA-JRC-WHO report. EEA Report. Copenhagen: European Environment Agency. http://www.eea.europa.eu/publications/eea_report_2008_4. ———. 2009a. Water resources across Europe — confronting water scarcity and drought. EEA Report. Copenhagen: European Environment Agency. http://www.eea.europa.eu/publications/water-resources-across-europe. ———. 2009b. Regional climate change and adaptation — The Alps facing the challenge of changing water resources. EEA Report. Copenhagen. http://www.eea.europa.eu/publications/alps-climate-change-and-adaptation-2009. ———. 2012. Towards efficient use of water resources in Europe. EEA Report. Copenhagen: European Environment Agency. http://www.eea.europa.eu/publications/towards-efficient-use-of-water. European Commission. 2007. “State aid/ Lithuania Aid no N 842/2006”. European Commission, Directorate General for Agriculture and Rural Development. http://ec.europa.eu/agriculture/stateaid/decisions/n84206_en.pdf. Feyen, Luc, and Rutger Dankers. 2009. “Impact of global warming on streamflow drought in Europe.” Journal of Geophysical Research 114 (September 15): D17116. doi:10.1029/2008JD011438. García-Herrera, Ricardo, Daniel Paredes, Ricardo M. Trigo, Isabel Franco Trigo, Emiliano Hernández, David Barriopedro, and Manuel A. Mendes. 2007. “The outstanding 2004/05 drought in the Iberian peninsula: Associated atmospheric circulation.” Journal of Hydrometeorology 8 (June): 483–498. doi:10.1175/JHM578.1. Generalitat de Catalunya. 2010. Pla de l’Energia de Catalunya 2006-2015. Revisió 2009. Generalitat de Catalunya - Departament d’Economia i Finances. http://www20.gencat.cat/docs/icaen/08_Institut/Documents/pecat0615_rev2009.pdf. Hisdal, Hege, Kerstin Stahl, Lena M Tallaksen, and Siegfried Demuth. 2001. “Have Streamflow Droughts in Europe Become More Severe or Frequent?” International Journal of Climatology 21 (3) (March 15): 317–333. doi:10.1002/joc.619. Keirle, Robert, and Colin Hayes. 2007. “A Review of Catchment Management in the New Context of Drinking Water Safety Plans.” Water and Environment Journal 21 (3) (September 1): 208–216. doi:10.1111/j.1747-6593.2007.00074.x. Lehner, Bernhard, Gregor Czisch, and Sara Vassolo. 2005. “The impact of global change on the hydropower potential of Europe: a model-based analysis.” Energy Policy 33 (7) (May): 839–855. doi:10.1016/j.enpol.2003.10.018. Lehner, Bernhard, Petra Döll, Joseph Alcamo, Thomas Henrichs, and Frank Kaspar. 2006. “Estimating the Impact of Global Change on Flood and Drought Risks in Europe: A Continental, Integrated Analysis.” Climatic Change 75 (3) (April): 273–299. doi:10.1007/s10584-006-6338-4. Rojas, R., L. Feyen, A. Bianchi, and A. Dosio. 2012. “Assessment of Future Flood Hazard in Europe Using a Large Ensemble of Bias Corrected Regional Climate Simulations.” Journal of Geophysical Research (in press). doi:10.1029/2012JD017461. van der Schrier, G., K.R. Briffa, P.D. Jones, and T.J. Osborn. 2006. “Summer Moisture Variability across Europe.” Journal of Climate 19: 2818–2834. doi:10.1175/JCLI3734.1. Stahl, K., H. Hisdal, L. Tallaksen, H. A.J. Lanen, J. Hannaford, and E. Sauquet. 2008. Trends in Low Flows and Streamflow Droughts Across Europe. Paris: UNESCO. http://library.wur.nl/WebQuery/wurpubs/374150. Sušnik, Andreja, and Blaž Kurnik. 2005. “Agricultural Drought Management: Status and Trends in Slovenia”. ICID 21st European Regional Conference 2005. Svensson, Cecilia, W. Zbigniew Kundzewicz, and Thomas Maurer. 2005. “Trend Detection in River Flow Series: 2. Flood and Low-flow Index Series / Détection De Tendance Dans Des Séries De Débit Fluvial: 2. Séries D’indices De Crue Et D’étiage.” Hydrological Sciences Journal 50 (5): 824. doi:10.1623/hysj.2005.50.5.811.

Indicator definition

• Water scarcity and drought events in Europe

• Projected change in minimum river flow with return period of 20 years

Units

• [dimensionless]
• % change

Policy context and targets

Context description

In April 2009 the European Commission presented a White Paper on the framework for adaptation policies and measures to reduce the European Union's vulnerability to the impacts of climate change. The White Paper stresses the need to improve the knowledge base and to mainstream adaptation into existing and new EU policies. The European Commission will be publishing an EU Adaptation Strategy in 2013. A number of Member States have already taken action, and several have prepared national adaptation plans.

The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, http://climate-adapt.eea.europa.eu/) to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.

Targets

No targets have been specified.

Related policy documents

• Climate-ADAPT: Mainstreaming adaptation in EU sector policies
  Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
• Climate-ADAPT: National adaptation strategies
  Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
• DG Climate Action: What is the EU doing about climate change?
  Activities of the EU regarding climate change (both mitigation and adaptation)
• White paper - Adapting to climate change: towards a European framework for action
  EU framework for adaptation to climate change, leading to a comprehensive EU adaptation strategy by 2013

Methodology

Methodology for indicator calculation

Water scarcity and drought events in Europe during the last decade are shown based on Tallaksen, 2007, personal communication. For the projections, an ensemble was applied consisting of simulations from 12 climate experiments conducted within the ENSEMBLES project, forced by the SRES A1B emission scenario for the period 1961-2100. Prior to driving the hydrological model LISFLOOD, climate simulations are corrected for bias in precipitation and temperature using a Quantile Mapping (QM) method.

Methodology for gap filling

Not applicable

Methodology references

• Rojas et al. 2012: Assessment of Future Flood Hazard in Europe Using a Large Ensemble of Bias Corrected Regional Climate Simulations. Rojas, R., Feyen, L., Bianchi, A. and Dosio, A. (2012) Assessment of Future Flood Hazard in Europe Using a Large Ensemble of Bias Corrected Regional Climate Simulations. Journal of Geophysical Research. doi:10.1029/2012JD017461

Data specifications

EEA data references

• No datasets have been specified here.

External data references

• European water archive

Data sources in latest figures

Uncertainties

Methodology uncertainty

Not applicable

Data sets uncertainty

Detailed data on water quantity is often difficult to assess, and homogeneous time series are generally shorter than those for meteorological data. It may, therefore, require substantially more time before statistically significant changes in hydrological variables can be observed than for meteorological variables, especially with respect to extreme events (floods and droughts). Quantitative projections of changes in precipitation and river flows at the basin scale remain highly uncertain due to the limitations of climate models and to scaling issues between climate and hydrological models.

The main data sources for European-wide studies of extreme hydrological events and their changes are global databases for natural disasters. These include general impact-oriented disaster databases such as EM-DAT ([1]) maintained by the Centre for Research on the Epidemiology of Disasters (CRED) and the NatCatService ([2]) maintained by Munich Re, as well as specific mostly event-oriented databases, such as the Dartmouth Flood Observatory ([3]). Some of the limitations of these databases included the use of thresholds for inclusion of an event, which may exclude smaller events with a significant regional impact, changes over time in the comprehensiveness of the coverage (see below), and privacy issues related to detailed data collected by the insurance industry. Improvements of these datasets are planned in coming years. The available data is currently evaluated, for example in the ongoing emBRACE project ([4]). A more detailed and comprehensive event-oriented database that also includes events without any (major) damages would be needed to separate the effect of climate change from socio-economic changes.

The reporting of flood and drought events has generally improved during the past few decades as a result of improvements in data collection and flows of information. As a result, it is often difficult to identify whether an increase in reported flood events (or their impacts) over time is due mostly to improvements in data collection or to actual changes in these events. Furthermore, river flood records are usually sourced from different institutions and often collected using a wide range of different assessment methods and rationales, which may have changed over time. This multitude of sources limits the comparability of key attributes associated with such events (e.g. economic losses, human casualties) across space and time.

As part of the preliminary flood risk assessment for the European directive on the assessment and management of flood risks (2007/60/EC) ([5]), EU Member States will give an overview of significant past floods. In addition, a European flood impact database could bring together publicly available inventories of flood events. At the national/regional level, such an inventory would be particularly useful to provide accurate data and assessments which would serve as a basis for disaster prevention. At the European level, these inventories could assist in tracking the trends in flood-disaster losses, and in mitigation programmes monitoring and obtaining a clearer picture of the linkages between climate change and floods and flood losses.

Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012 (http://www.eea.europa.eu/publications/climate-impacts-and-vulnerability-2012/)

[1] See http://www.emdat.be online.

[2] See http://www.munichre.com/geo online.

[3] See http://floodobservatory.colorado.edu/ online.

[4] See http://embrace-eu.org/ online.

[5] See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2007:288:0027:0034:EN:PDF online.

Rationale uncertainty

No uncertainty has been specified