The role of natural approaches for protecting water resources and managing related risks (including floods and droughts) has been highlighted by DG ENV and has been the objective of several policy initiatives and communications:
Natural water retention measures are measures that aim to safeguard and enhance the water storage potential of landscape, soil, and aquifers, by restoring ecosystems, natural features and characteristics of water courses and using natural processes. They support Green Infrastructure by contributing to integrated goals dealing with nature and biodiversity conservation and restoration, landscaping, etc. They are adaptation measures that use nature to regulate the flow and transport of water so as to smooth peaks and moderate extreme events (floods, droughts, desertification, salination). They reduce vulnerability of water resources to CC and other anthropogenic pressures. They are relevant both in rural and urban areas. Examples of NWMR include:
Although they are primarily designed to regulate the water cycle these measures will be a key contribution to EU green infrastructure by improving connectivity between existing nature areas and enhancing landscape permeability. In addition, the areas benefiting from these measures will often be multifunctional, allowing farming, forestry, recreation and ecosystems conservation to operate together in the same space. They can also provide additional benefits including water depollution and purification, cleaner air and reduced temperatures in urban areas, energy efficiency in buildings or water treatment, climate change mitigation (reduced energy demands and carbon sequestration by vegetation), increased property values, and impacts on job creation and innovation. Their multi-functionality contributes to their cost-efficiency and renders them good candidates for sustainable climate adaptation measures. Quantification and Valuation of these ESS is important for carrying out effective Cost Benefit Analysis related to these measures.
On the cost side, particular attention needs to be paid to the opportunity costs linked to the land-use requirements of the measure. These costs can be translated either into land acquisition, or into compensation/service payments. A proper knowledge of the cost savings in hard infrastructure for flood protection and water supply will also be needed. It is increasingly recognised that attempts to control rivers through hard engineering alone may be counterproductive, and that natural water retention measures may offer the best return in terms of societal benefits from flood control and other ecosystem services such as water quality regulation and water provisioning, food or material production, biodiversity protection, recreation, air quality and climate regulation. Most strategies and projects for water management, disaster prevention and climate change adaptation mix both approaches, but a better understanding of costs and benefits is needed.
Natural water retention measures are already being implemented or planned in various EU river basins. However, the potential impacts of climate change or of other man-made pressures may trigger the need for implementing these measures in other locations, or to modify the scope or the intensity of these measures.
In the context of the impact assessment for the Communication "The Blueprint to Safeguard Europe's Water Resources" a Commission funded literature review on Natural Water Retention Measures was conducted: Costs, benefits and climate proofing of natural water retention measures and the measures were assessed for their hydrological impact in a study based on Pan-European modeling: Evaluation of the effectiveness of Natural Water Retention Measures.
In line with the Blueprint proposals in the 2013-2015 CIS Work Programme, a deliverable is foreseen under the mandate of Working Group Programme of Measures (WG PoM): "Guidance or other tool on Natural Water Retention Measures by 2014". To support this DG ENV has procured a Pilot Project on NWRM:
A parallel study on Integrating Ecosystem Services with Water Framework Directive and Floods Directive Implementation will also provide input to the pilot project.