Constructed Wetlands for nutrient removal
Constructed wetlands are recognized as valuable nature-based solutions for the reduction nutrient discharge in water bodies at eutrophication risk, such as lakes and coastal lagoons. For instance, constructed wetlands were satisfactorily applied to reduce the nutrient loads conveyed by agricultural drainage channels, which are driven by agricultural runoff.
Advantages
- nutrient removal from agricultural drainage channels discharging in water bodies sensitive to eutrophication
- water quality improvement
- wetland restoration with high naturalistic value
- possibility to combine other ecosystem services, such as flood mitigation (multiple purposes green blue infrastructures)
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IRIDRA's experience
Several intervents were designed by Consorzio di Bonifica Acque Risorgive to reduce the floods events and the nutrient loads discharged in the Venice lagoon. Among them, IRIDRA has designed in collaboration with ETATEC two free water surface systems of 1.6 and 2.2 hectares, sited inside multi-purpose detention basins. Except for the flood protection, the wetlands are designed to remove 1.1 and 3.9 tonnes of nitrogen per year, function of different management procedures (i.e. with or without harvesting).
Free water surface wetland system for removal of nutrient conveyed by the irrigation network managed by Consorzio di Bonifica Acque Risorgive, designed by IRIDRA
