In addition to the rivers, the Douro basin also hosts a large number of lakes and lagoons such as the Negra de Urbión Lake, in the Picos de Urbión, the Grande de Gredos Lake, in Gredos, the Sanabria Lake, in Zamora or the La Nava de Fuentes Lake in Palencia. Also emphasize a great number of reservoirs, fed by the water coming from the rains and the thaw of the snowy summits. Thus, Castile and León, despite not having abundant rainfall, is one of the communities in Spain with the highest level of water dammed.

Many of these natural lakes are being used as an economic resource, boosting rural tourism and helping to conserve ecosystems. The Sanabria Lake was a pioneer in this.