Five years of data
In February 2020, we launched the first water quality monitoring protocol at six points along the Mondego watershed. Today, five years on, we have 1,847 samples, 23 trained volunteers, and a story worth telling.
What the data says
What surprised us
Nitrate concentrations in the stretch downstream of Coimbra fell 18% between 2021 and 2024 — a drop we cannot explain by rainfall variation alone. Our hypothesis is that there were changes in agricultural practices at two partner farms that joined the agri-environment scheme in 2021.
What confirmed our suspicions
The stretch between the Aguieira dam and Penacova continues to show worrying signs of eutrophication in summer. Chlorophyll-a values exceed recommended limits in 7 of the 10 monitored summers.
What we still do not know
The correlation between turbidity spikes and upstream wildfire events needs more years of data to be conclusive.
Next steps
This report will be submitted to the Portuguese Environment Agency as input for the revision of the Tagus and Western Streams River Basin Management Plan. If you want access to the full dataset, it is available under an open licence in our repository.