River flow

Assessment versions

Published (reviewed and quality assured)

• No published assessments

Rationale

Justification for indicator selection

River flow is a measure of overall fresh water availability in a river basin. Variations in river flow are determined mainly by the seasonality of precipitation and temperature, as well as by catchment characteristics such as geology, soils and land cover. Changes in temperature and precipitation patterns due to climate change modify the annual water budget of river basins as well as the timing and seasonality of river flows. The consequent changes in water availability may adversely affect ecosystems and several socio-economic sectors including abstraction for drinking water, agriculture, industry, energy production and navigation. Extreme dry periods with low river flow events can have considerable economic, societal and environmental impacts.

Scientific references

• No rationale references available

Indicator definition

• Trends in monthly stream flow

• Projected change in average annual and seasonal river flow

• Projected change in daily average river flow

Units

• standard deviations per year
• %
• m³/s

Policy context and targets

Context description

In April 2013 the European Commission presented the EU Adaptation Strategy Package (http://ec.europa.eu/clima/policies/adaptation/what/documentation_en.htm). This package consists of the EU Strategy on adaptation to climate change /* COM/2013/0216 final */ and a number of supporting documents. One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which should occur through Bridging the knowledge gap and Further developing Climate-ADAPT as the ‘one-stop shop’ for adaptation information in Europe. Further objectives include Promoting action by Member States and Climate-proofing EU action: promoting adaptation in key vulnerable sectors. Many EU Member States have already taken action, such as by adopting national adaptation strategies, and several have also prepared action plans on climate change adaptation.

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: Adaptation in EU policy sectors
  Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
• Climate-ADAPT: Country profiles
  Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
• DG CLIMA: Adaptation to climate change
  Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives in the future. This web portal provides information on all adaptation activities of the European Commission.
• EU Adaptation Strategy Package
  In April 2013, the European Commission adopted an EU strategy on adaptation to climate change, which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it enhances the preparedness and capacity of all governance levels to respond to the impacts of climate change.

Methodology

Methodology for indicator calculation

Streamflow trends are calculated by the slopes of the Kendall-Theil robust line for standardized annual and monthly streamflow, as well as for summer low flow magnitude and timing. Streamflow records from 441 small catchments in 15 countries across Europe.

Projected change in mean annual and seasonal river flow between the climate change scenario (SRES A1B, 2071–2100) and the control period (1961–1990) are shown. Simulations with LISFLOOD based on an ensemble of 11 RCMs.

Projected change in daily average river flow between 1961–1990 (black line) and 2071–2100 (blue line) were simulated with LISFLOOD and driven by HIRHAM – HadAM3H/HadCM3 based on IPCC scenario A2.

Methodology for gap filling

Not applicable

Methodology references

No methodology references available.

Data specifications

EEA data references

• No datasets have been specified here.

External data references

• Global trends in streamflow and water availability
• Global Runoff Database

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.

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/)

Rationale uncertainty

No uncertainty has been specified