Water retention

Assessment versions

Published (reviewed and quality assured)

• No published assessments

Rationale

Justification for indicator selection

Soil water retention is a major soil hydraulic property that governs soil functioning in ecosystems and greatly affects soil management. Soil moisture forms a major buffer against flooding, and water capacity in subsoil is a major steering factor for plant growth. The effects of changes in soil water retention depend on the proportions of the textural components and the amount of organic carbon present in the soil. At low carbon contents, an increase in carbon content leads to an increase in water retention in coarse soils and a decrease in fine-textured soils. At high carbon contents, an increase in carbon content results in an increase in water retention for all soil textures (Rawls et al., 2003). Soil organic matter can absorb up to twenty times its weight in water. Changes in temperature result in changes in evapotranspiration, soil moisture, and infiltration. These will also influence groundwater recharge by changing the ratio of surface run-off to infiltration. Projections for climate change indicate greater droughts in some areas, which might lead to substantial reductions in summertime soil moisture, and more rainfall -- even too much -- in others, and also increases in the off-site impacts of soil erosion. Maintaining or even enhancing the water retention capacity of soils can therefore play a positive role in mitigating the impacts of more extreme rainfall intensity and more frequent and severe droughts. Harmonised time-series on relevant soil properties are not available but should be developed. The development of projections for the soil characteristics presented here (subsoil available water capacity and topsoil moisture), which depend entirely on soil properties, is difficult due to lack of data to validate the models. Further research is needed using satellite information and linking this to representative observed data.

Scientific references

• References Calanca, P.; Roesch, A.; Jasper, K.; Wild, M., 2006. Global warming and the summertime evpotranspiration regime of the Alpine region. Climatic Change 79: 65-78. Rawls, W. J.; Pachepsky, Y. A.; Ritchie, J. C.; Sobecki, T. M.; Bloodworth, H., 2003. Effect of soil organic carbon on soil water retention, Geoderma, 2003. Elsevier.

Indicator definition

• Modelled summer soil moisture (1961-1990) and projected changes (2070-2080) over Europe

Units

http://www.eea.europa.eu/publications/eea_report_2008_4/pp111-148CC2008_ch5-7to9_Terrestrial_ecosystems_soil_and_agriculture.pdf

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 aim is to increase the resilience to climate change of health, property and the productive functions of land, inter alia by improving the management of water resources and ecosystems. More knowledge is needed on climate impact and vulnerability but a considerable amount of information and research already exists which can be shared better through a proposed Clearing House Mechanism. The White Paper stresses the need to mainstream adaptation into existing and new EU policies. A number of Member States have already taken action and several have prepared national adaptation plans. The EU is also developing actions to enhance and finance adaptation in developing countries as part of a new post-2012 global climate agreement expected in Copenhagen (Dec. 2009). For more information see: http://ec.europa.eu/environment/climat/adaptation/index_en.htm

Targets

No targets have been specified

Related policy documents

No related policy documents have been specified

Methodology

Methodology for indicator calculation

http://www.eea.europa.eu/publications/eea_report_2008_4/pp111-148CC2008_ch5-7to9_Terrestrial_ecosystems_soil_and_agriculture.pdf

Methodology for gap filling

http://www.eea.europa.eu/publications/eea_report_2008_4/pp193-207CC2008_ch8_Data_gaps.pdf

Methodology references

No methodology references available.

Data specifications

EEA data references

• No datasets have been specified here.

External data references

• Daily Soil Moisture of Europe

Data sources in latest figures

Uncertainties

Methodology uncertainty

http://www.eea.europa.eu/publications/eea_report_2008_4/pp193-207CC2008_ch8_Data_gaps.pdf

Data sets uncertainty

http://www.eea.europa.eu/publications/eea_report_2008_4/pp193-207CC2008_ch8_Data_gaps.pdf

Rationale uncertainty

No uncertainty has been specified