When the structure or natural water flow of a river or other watercourse is modified (for instance by dredging or the construction of a hydropower plant), it can have an effect on the ecological status of the watercourse. Such hydromorphological changes to retention structures, habitat/sediment composition, flow regime and bed gradient can modify the ability of rivers to retain pollutants and sediments, increase their vulnerability to pollution and cause the deterioration of habitats, with knock-on effects on fauna and flora. In particular, hydromorphological changes in watercourses that constitute migratory fish habitats can make it impossible for them to migrate.
LIFE AGUEDA’s main objective is to eliminate, or substantially mitigate, the hydromorphological pressures identified in the Vouga River Basin, in order to help re-establish good ecological status, as required by the Water Framework Directive and the applicable river basin management plan.
To achieve this target, the project will implement a series of solutions to renaturalise the river and restore or recreate its associated aquatic and terrestrial habitats. Actions will include the following: Building fish passes that mimic natural conditions; Translocating juvenile European eels; Restoring riparian habitat; Engaging with anglers on fish monitoring; and Setting up mobile fish auctions to create market differentiation for fish from the project area.
The expected benefits for migratory fish populations will not only contribute to meeting the WFD’s ecological targets but also its multi-use objectives, encompassing the needs established under the Floods Directive. Habitats Directive, EU Biodiversity Strategy to 2020 as well as the eel management plans resulting from the 2007 EU Regulation on European eel stocks.
The project will assess the socioeconomic effects of the activities carried out, increasing their replicability potential.
Expected results: Better resilience to flooding for 35 ha of agricultural plains, due to the improvement of riparian woods and riverbanks along 9 km of river margins; Improved ecological structure for 30 ha of riparian galleries, due to restoration work with autochthonous species and control/eradication of invasive alien flora; 51 km of river stretches with improved ecological status, taking into account the mitigation of discontinuity, river morphology and conservation status of aquatic and terrestrial habitats; Improved structure and substrate for 68 ha of river bed and associated reduction of siltage along eight stretches of river, restoring lotic conditions; Removal of eight obstacles from the Águeda and Alfusqueiro rivers, creating the conditions for continuity in 34 km of river corridor; Design/installation of three prototype fish passes mimicking natural conditions to improve continuity in the Águeda and Alfusqueiro rivers, with an expected change of 30-75% compared to actual levels; Three areas of terrestrial habitats made suitable for multiple use (conservation, awareness raising and recreational/outdoor use); Sustainable management of fisheries along some 50 km of river, taking into account the implementation of regulations targeted at marine, estuarine and freshwater commercial fisheries; A pilot “mobile auction” system, aimed at market differentiation of fish from the project area. This is expected to lead to a 25% increase in the market value of the fish; Specific mitigation measures covering 25 km of the Vouga River, allowing for the translocation of 500 000 juvenile European eels through a pilot solution for capturing, transporting and releasing them in improved habitats; Direct benefits for a critically endangered diadromous fish species and four other endangered and protected species; 1 000 anglers using a pilot application for monitoring by volunteers; At least one replication/transfer project proposed in Portugal; and At least one replication/transfer project with other EU beneficiaries.