The enrichment of waters with nutrients enhances algal development. This phenomena is called
eutrophication, a frequent situation of Iberian rivers and reservoirs.

Purification of wastewater and the efficient use of fertilizers are some measures to reduce
eutrophication.

The monitoring and assessment of eutrophication require the control of some parameters:

• Nutrients (mainly soluble phosphorus and nitrate).
• Chlorophyll concentration.
• Density and taxonomic composition of phytoplankton and/or phytobenthos.
• Abundance and taxonomic composition of macrophytes.