River basins

Source: MITECO Updated 06 OCT 2026

Cantábrico Occidental

Capacity485 hm³

Stored water276 hm³

Main reservoirs

Salime41.6%Capacity: 238 hm³Doiras73.2%Capacity: 97 hm³Arbón90.24%Capacity: 41 hm³Tanes58.82%Capacity: 34 hm³

Cantábrico Oriental

Capacity73 hm³

Stored water42 hm³

Main reservoirs

Añarbe55.26%Capacity: 38 hm³Ordunte50.0%Capacity: 22 hm³Ibiur75.0%Capacity: 8 hm³San Antón80.0%Capacity: 5 hm³

Cuenca Mediterránea Andaluza

Capacity1,174 hm³

Stored water750 hm³

Main reservoirs

Guadalhorce-Guadalteba89.61%Capacity: 279 hm³Viñuela, La84.24%Capacity: 165 hm³Cuevas de Almanzora9.32%Capacity: 161 hm³Rules81.98%Capacity: 111 hm³

Cuencas Internas de Cataluña

Capacity677 hm³

Stored water494 hm³

Main reservoirs

Susqueda78.97%Capacity: 233 hm³Sau68.48%Capacity: 165 hm³La Baells70.64%Capacity: 109 hm³La Llosa del Cavall75.0%Capacity: 80 hm³

Cuencas Internas del País Vasco

Capacity21 hm³

Stored water15 hm³

Main reservoirs

Ibai-Eder63.64%Capacity: 11 hm³Urkulu80.0%Capacity: 10 hm³

Duero

Capacity7,602 hm³

Stored water3,715 hm³

Main reservoirs

Almendra55.76%Capacity: 2,649 hm³Ricobayo37.82%Capacity: 1,145 hm³Riaño37.29%Capacity: 641 hm³Santa Teresa46.98%Capacity: 496 hm³

Ebro

Capacity7,813 hm³

Stored water3,546 hm³

Main reservoirs

Mequinenza57.47%Capacity: 1,373 hm³Canelles46.1%Capacity: 679 hm³Ebro53.05%Capacity: 541 hm³Yesa13.87%Capacity: 447 hm³

Galicia Costa

Capacity684 hm³

Stored water343 hm³

Main reservoirs

Portodemouros46.8%Capacity: 297 hm³Eume68.29%Capacity: 123 hm³Fervenza37.86%Capacity: 103 hm³Ribeira, A51.52%Capacity: 33 hm³

Guadalete-Barbate

Capacity1,651 hm³

Stored water1,243 hm³

Main reservoirs

Guadalcacín II84.38%Capacity: 800 hm³Barbate68.86%Capacity: 228 hm³Zahara-El Gastor65.47%Capacity: 223 hm³Bornos64.5%Capacity: 200 hm³

Guadalquivir

Capacity8,030 hm³

Stored water5,546 hm³

Main reservoirs

Iznájar73.15%Capacity: 920 hm³Breña II, La76.18%Capacity: 823 hm³Negratín58.49%Capacity: 571 hm³Tranco de Beas71.94%Capacity: 506 hm³

Guadiana

Capacity9,538 hm³

Stored water6,875 hm³

Main reservoirs

La Serena81.73%Capacity: 3,219 hm³Cijara75.61%Capacity: 1,505 hm³Alange50.94%Capacity: 852 hm³Orellana73.39%Capacity: 808 hm³

Júcar

Capacity2,846 hm³

Stored water1,476 hm³

Main reservoirs

Alarcón71.38%Capacity: 1,118 hm³Tous - La Ribera11.08%Capacity: 379 hm³Contreras68.42%Capacity: 361 hm³Benagéber36.2%Capacity: 221 hm³

Miño - Sil

Capacity3,030 hm³

Stored water1,671 hm³

Main reservoirs

Belesar28.09%Capacity: 655 hm³Portas, Las56.72%Capacity: 536 hm³Bárcena63.93%Capacity: 341 hm³Bao85.71%Capacity: 238 hm³

Segura

Capacity1,140 hm³

Stored water562 hm³

Main reservoirs

Cenajo58.58%Capacity: 437 hm³La Pedrera35.77%Capacity: 246 hm³Fuensanta72.38%Capacity: 210 hm³Algeciras17.78%Capacity: 45 hm³

Tajo

Capacity11,056 hm³

Stored water5,988 hm³

Main reservoirs

Alcántara55.82%Capacity: 3,160 hm³Buendía46.74%Capacity: 1,705 hm³Valdecañas54.63%Capacity: 1,446 hm³Gabriel y Galán37.32%Capacity: 911 hm³

Tinto, Odiel y Piedras

Capacity229 hm³

Stored water145 hm³

Main reservoirs

Piedras43.33%Capacity: 60 hm³Sancho82.76%Capacity: 58 hm³Jarrama60.47%Capacity: 43 hm³Olivargas75.86%Capacity: 29 hm³

Data: MITECO · AEMET