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Engineered ponds in peatlands that have been ditched to enhance forest production have the potential to retain water in the landscape and trap sediment without adversely affecting tree growth. Such measures have the potential to limit hydrograph peaks and potentially reduce flooding associated with snowmelt.
- Elaborated by NWRM project experts and validated by the European Commission

"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)." (Source: susdrain)

An enclosed body of water, usually but not necessarily fresh water, from which the sea is excluded. (Source: WHIT)

From the perspective of natural water retention measures (NWRM), reconnection is the process of improving hydrological connection in the landscape, both through linking water bodies and through improving the connectivity between rivers and their adjacent floodplains. Reconnection can make use of historical and currently water channels to restore previously existing hydrological connectivity and functioning.

A mulch is a layer of material applied to the surface of an area of soil. Its purpose is any or all of the following:·       to conserve moisture·       to improve the fertility and health of the soil·       to reduce weed growth·       to enhance the visual appeal of the areaMulching as NWRM is using organic material (e.g. bark, wood chips, grape pulp, shell nuts, green waste, leftover crops, compost, manure, straw, dry grass, leaves etc.) to cover the surface of the soil. It may be applied to bare soil, or around existing plants. Mulches of manure or compost will be incorporated naturally into the soil by the activity of worms and other organisms. The process is used both in commercial crop production and in gardening, and when applied correctly can dramatically improve the capacity of soil to store water.

The sloping side of any hollow in the ground, especially when bordering a river. (Source: CED)

Planting and maintaining tree cover in near-stream areas can have multiple benefits including erosion and nutrient leaching control. They will also slow the stream velocity during high flow flood events and may have beneficial effects on stream temperature. Maintaining treed forest buffers during clearcutting can help minimizing the adverse effects of forestry on water quality and may have additional biodiversity benefits.
- Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

To ease the overall functioning of the river, some hydrographical network elements could be reconnected, including the so-called hydraulic annexes. This will allow for improvement of lateral connectivity, diversifying flows and habitats, but also cleaning the secondary arms that play a key role for retention in high water periods.
- 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

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.

The suppression of lateral constraints consists in removing some bank protection in order to enhance lateral connection of the river, diversifying flows (depth, substrate, speed), diversify habitats but also capping floods in the mainstream.
- Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Meadows are areas or fields whose main vegetation is grass, or other non-woody plants, used for mowing and haying.ﾠ Pastures are grassed or wooded areas, moorland or heathland, generally used for grazing. Due to their rooted soils and their permanent cover, meadows and pastures provide good conditions for the uptake and storage of water during temporary floods. They also protect water quality by trapping sediments and assimilating nutrients.
- Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Phosphates from agriculture are an important contributor to phosphorus loading on water bodies. Phosphorus is considered to be a limiting factor in the process of eutrophication that can generally be regarded as the enrichment of surface waters by nutrients which causes overgrowth of algae and weeds. The result is deoxygenation of waters that can kill fish and other aquatic life. Algae growth can also be a hazard to human health.

Afforestation of reservoir catchments can have multiple benefits. It can reduce sediment inputs from the catchment, lengthening the life of the reservoir, and may also have beneficial effects on water quality in some cases when peatlands are afforested. Afforestation can reduce peak flows and help to maintain base flows. The benefits of afforestation must be balanced against the potential for increased evapotranspiration from a rapidly growing forest.
- Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Gently sloping vegetated strips of land that provide opportunities for slow conveyance and infiltration. Designed to accept runoff as overland flow from upstream and to slow the progress of this runoff.
- Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Early sowing refers to sowing up to six weeks before the normal sowing season.ﾠ This allows for an earlier and quicker development of crops and of a root network that leads to soil protection.ﾠ The period in which the soil lies bare is shorter and, therefore, erosion and run-off are less significant and water infiltration is improved.ﾠ Early sowing can also help to mitigate the extreme ETP rates typical of Mediterranean summers.ﾠ However, early sown plants are frost sensitive; therefore farmers run the risk of losing the crops because of the low temperatures.ﾠ In northern countries, temperature in spring (March) can be adequate but the risk of frost is still serious until May.ﾠ Therefore, early sowing requires specific tools (plastic tunnel covers, onsite green house, etc.) and cannot be applied by any farmers for any crops.
- Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

Rainfall that is stored on a vegetation canopy and later evaporated back to the atmosphere.

Ditch blocking in managed peatland forests can be used to slow water and trap sediment after forest harvesting. The ditches can be made of wood logs or gabions, for example.
- Elaborated by NWRM project experts and validated by the European Commission

Continuous cover forestry (CCF) is a broad term encompassing a wide variety of forest management practices. One key feature of is that biomass removal is based either on small clearcuts or selective harvesting. Smaller clearcuts may create less hydrological disturbance but some of the filtration benefits associated with forest soils may be lost as a result of the greater driving and road maintenance needed for continuous harvesting.
- Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

The (monetary) value of resources deployed for the implementation of any NWRM, which includes upfront capital expenditures, either from new investments or the replacement of assets in past investments; depreciation allowances (annualised cost or replacing the accounting value of existing assets in the future); operating expenditures (those incurred to keep the NWRM running in an efficient manner); maintenance expenditures (for preserving existing or new assets in good functioning order throughout their useful life); and decommissioning costs (those incurred at the end of the lifecycle of the NWRM).

Collecting and storing rainwater for subsequent use ﾖ for example, using water butts or larger storage tanks.
- Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission

The cost per year of implementing a NWRM over its entire lifespan. EAC is used when comparing NWRMs of unequal lifespans. It is estimated through listing all capital expenditures and when they are incurred; calculating the net present value of expenditures, once discounted; and converting this net present value into an annuity

Lakes are by definition water retention facilities; they store water (for flood control) and provide water for many purposes such as water supply, irrigation, fisheries, tourism, etc.ﾠ In addition, they serve as sinks for carbon storage and provide important habitats for numerous species of plants and animals, including waders.ﾠ In the past, lakes have sometimes been drained to free the land for agriculture purposes, or have simply not been maintained and have silted up.ﾠ Restoring lakes is re-introducing them where they have been in former times or revitalising them.
- Based on Stella definitions, adapted by NWRM project experts and validated by the European Commission