...SEâ database of the European Environmental Agency, approximately half of all Spanish reservoirs are at risk of eutrophication. One Spanish reservoir defined as eutrophic is Cuerda del Pozo in Soria (Castilla y Leon, Spain). This represents an excellent case study because it has many uses, including as a water supply to the city of Soria (100 000 inhabitants), for recreation, and as a water suppl ...