During Spring and Summer 2025, the CONNECT project carried out an extensive data-collection campaign across the Alviela River basin to contribute to the environmental forecasting tools and dam-removal framework to be developed in the next phases of the project.
Field surveys focused on fish communities, macroinvertebrates, water quality, and river morphology, all crucial indicators for assessing ecological, hydromorphological, and biochemical conditions before the removal of Sourinho Weir.
In July, the CONNECT team conducted electrofishing surveys at multiple sites, including Sourinho Weir, Olhos de Água, Ponte Ferreira and the Mouchão waterfall. Results showed a high diversity of native fish, such as Iberian chub, barbel, loach, and nase species. The presence of invasive species was detected, like pumpkinseed and bleak. At Sourinho Weir the CONNECT team tagged 210 fish with PIT tags (upstream and downstream of the weir) to assess movement patterns and evaluate connectivity impacts.
The team also recorded four freshwater bivalve species, including three native species, which is an indicator of good local water quality. Complementing the fish work, macroinvertebrate samples were collected at five locations near Sourinho Weir and are now being analysed by the team at the University of Coimbra.
On the biochemistry side, water samples collected in June and analysed at Técnico Lab suggest generally good water-quality conditions at this stage. Hydromorphological monitoring will continue in Autumn with a bathymetric survey to establish the baseline prior to the weir removal.
These data form the foundation for CONNECT’s next steps: modelling environmental responses to dam removal and developing a practical framework to support decision-makers and local communities in planning restoration interventions.