Nemus was responsible for the characterization of surface waters, with the goal of providing support information to define the condition of the water masses from the hydrographic regions of the Tagus River and the streams in the West.

The study, which involved 90 waterlines and 93 sampling locations, comprised the reconnaissance of these locations, the characterization of the water quality through in situ measuring and sampling for laboratory analysis, the determination of the water flows and the analysis of the results obtained in the three sampling campaigns.