Code
N06
Sector
Hydro Morphology
The complete description of the NWRM
Summary

Seasonal streams or intermittent rivers are rivers for which surface water ceases to flow at some point in space and time. They comprise a large proportion of the global river network and are characterized by dynamic exchanges between terrestrial and aquatic habitats. These habitats support aquatic, semi-aquatic, and terrestrial biota. Seasonal streams provide essential ecosystem services to society, including flood control and irrigation. The abundance and distribution of seasonal streams, and their natural intermittent flow regimes, are being altered by climate change, water abstraction and inter-basin transfers. Despite their values and ongoing alterations, seasonal streams are chronically under-studied and protective management is inadequate.

 

Restoring and reconnecting seasonal streams with the river consists in, therefore favouring the overall functioning of the river by restoring lateral connectivity, diversifying flows and ensuring the proper functioning of these seasonal streams for a better water retention during floods.

Illustration(s)

 

Tributary useful during flooding, (Scotland, UK)

Source: http://www.fadsdirectory.com/flood-alleviation

Possible benefits with level
Benefits Level
PO1 - Improving status of biology quality elements
Medium
PO2 - Improving status of physico-chemical quality elements
Medium
PO3 - Improving status of hydromorphology quality elements
Medium
PO4 - Improving chemical status and priority substances
High
PO5 - Improving quantitative status
Medium
PO6 - Improving chemical status
Medium
PO7 - Prevent surface water status deterioration
Medium
PO8 - Prevent groundwater status deterioration
Low
PO9 - Take adequate and co-ordinated measures to reduce flood risks
High
PO10 - Protection of important habitats
High
PO11 - Better protection for ecosystems and more use of Green Infrastructure
High
PO12 - More sustainable agriculture and forestry
Low
PO13 - Better management of fish stocks
Medium
PO14 - Prevention of biodiversity loss
High
ES1 - Water storage
Medium
ES2 - Fish stocks and recruiting
Medium
ES3 - Natural biomass production
Low
ES4 - Biodiversity preservation
High
ES5 - Climate change adaptation and mitigation
Medium
ES6 - Groundwater/aquifer recharge
Medium
ES7 - Flood risk reduction
Medium
ES8 - Erosion/sediment control
High
ES9 - Filtration of pollutants
Medium
ES11 - Aesthetic/cultural value
Medium
BP1 - Store runoff
High
BP2 - Slow runoff
High
BP3 - Store river water
High
BP4 - Slow river water
High
BP5 - Increase evapotranspiration
Low
BP6 - Increase infiltration and/or groundwater recharge
High
BP7 - Increase soil water retention
Medium
BP8 - Reduce pollutant sources
Low
BP9 - Intercept pollution pathways
Medium
BP10 - Reduce erosion and/or sediment delivery
High
BP11 - Improve soils
Low
BP12 - Create aquatic habitat
Low
BP13 - Create riparian habitat
High
PO14 - Prevention of biodiversity loss
Low
BP15 - Enhance precipitation
Low
BP16 - Reduce peak temperature
Low
BP17 - Absorb and/or retain CO2
Low

Case studies per NWRM