Freshwater glossary

The reconstitution of the alluvial mattress consists in leveling-up the river bed and/or reactivating the bank erosion in order to stop the incision of the river bed. It can allow better connection with side arms, level-up the water level at low flow periods, diversifying flows (depth, substrate, speed), diversify habitats and increase retention times. - Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Sediment capture ponds are widely used to "slow down" water being drained from boreal forests. The main function of the sediment capture ponds is to remove prevent pollution of receiving waters downstream of a forest by removing suspended sediment and associated pollutants. - Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Excavations, typically filled with gravel, designed to store water and allow it to infiltrate into underlying soils or aquifers.ﾠ Soakaways would typically receive point-source inflow (e.g. from roof drainage).ﾠﾠ - Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

The management of land to minimise soil erosion to maintain soil and water resources, and provide sustainable benefits in the long term.

Those expenditures that, once committed, cannot be (easily) recovered. These costs arise because some activities require specialized assets that cannot be readily diverted to other uses.

"Supplementary" measures are those measures designed and implemented in addition to the basic measures, with the aim of achieving the objectives established pursuant to Article 4 of the WFD. Part B of Annex VI contains a non-exclusive list of such measures. Member States may also adopt further supplementary measures in order to provide for additional protection or improvement of the waters covered by this Directive, including in implementation of the relevant international agreements referred to in Article 1.

"Approaches to manage surface water that take account of water quantity (flooding), water quality (pollution)ﾠ and amenity issues are collectively referred to as Sustainable Drainage Systems (SuDS). SuDS mimic nature and typically manage rainfall close to where it falls. SuDS can be designed to slow water down (attenuate) before it enters ﾠstreams, rivers and other watercourses, they provide areas to store water in natural contours and can be used to allow water to soak (infiltrate) into the ground or evaporated from surface water and lost or transpired from vegetation (known as evapotranspiration)."

Sustainable Urban Drainage Systems (or SUDS) are a sequence of water management practices, green infrastructures and measures designed to drain surface water in a manner that mimics the natural hydrologic cycle and will provide a more sustainable approach to rainwater management than what has been the conventional grey infrastructure practice of routing run-off through a pipe to a receiving watercourse.

Shallow, broad and vegetated channels designed to store and/or convey runoff. - Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

There is some evidence that planting trees on some Mediterranean hillslopes can assist in cloud formation and precipitation. The forests assist in "trapping" rising air and condensing atmospheric water vapour. This work has been pursued by Milan Milan, amongst others. - Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Temporary streams are of particular importance when it comes to water storage and time retention especially in flash flood prone areas. Some measures can be directly implemented in order to ensure their proper functioning. - Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Traditional terraces consist of nearly level platforms built along contour lines of slopes, mostly sustained by stone walls, used for farming on hilly terrain.ﾠ When properly built and well maintained, terraces can reduce erosion and surface run-off by slowing rainwater to a non-erosive velocity.ﾠ So-called traditional terracing involves less disturbance of the terrain than modern terracing, as it does not involve significant levelling or cutting using heavy machinery.ﾠ - Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Efforts (either monetary outlays or consumption of any other resources, such as time) of administering, monitoring, and enforcing a NWRM. Policy-making involves political costs that are absent in private exchanges.

Urban planning that incorporates trees can have multiple benefits. Trees in urban areas have multiple benefits including increased infiltration and other benefits including shade and amenity value. - Elaborated by NWRM project experts, validated by th European Commission

Within the framework of natural water retention measures (NWRM), urban planning refers to the application of the "Grey to Green" principle within cities. The specific focus of urban planning for NWRM is to achieve sustainable water management by mimicking natural functions and processes in the urban environment.

Urban forest parks or protected areas provide multiple benefits including increased water infiltration, pollutant filtration, reductions in peak flow and maintenance of base flows. Urban forests also have many other aesthetic, biodiversity and quality of life benefits. - Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Water retention covers a wide set of mechanisms (see synthesis document n°1) the effect of which are to increase the capture of water by aquifers, soil, and aquatic and water dependent ecosystems. More precisely it refers to capabilities of catchments (including wetlands, rivers and floodplains but also other land areas) to hold or retain as much water as possible during periods of abundant or even excessive precipitation, so that water is available for use during dry periods and runoff peaks are minimized.

"Water sensitive driving" requires an awareness of the wet areas (mires, peatlands, etc.) in the landscape and an ability to avoid them while conducting forestry operations. Water sensitive driving is focussed primarily on minimizing water quality impacts of forestry including nutrient leakage and an increased potential for methylmercury formation.

Wetlands restoration and creation can involve: technical, spatially large-scale measures (including the installation of ditches for rewetting or the cutback of dykes to enable flooding); technical small-scale measures such as clearing trees; as well as changes in land-use and agricultural measures, such as adapting cultivation practices in wetland areas.ﾠ Wetland restoration can improve the hydrological regime of degraded wetlands and generally enhance habitat quality. (Creating artificial or constructed wetlands in urban areas can also contribute to flood attenuation, water quality improvement and habitat and landscape enhancement). - Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Areas that are inundated by surface or ground water with frequency sufficient to support a prevalence of vegetative or aquatic life that requires saturated or seasonally saturated soil conditions for growth or reproduction. Wetlands provide both stormwater attenuation and treatment, comprising shallow ponds and marshy areas covered in aquatic vegetation.ﾠ Wetlands detain flows for an extended period to allow sediments to settle and to remove contaminants.ﾠ They also provide runoff attenuation and can provide significant ecological benefits.