Hydrographic Confederations of Spain: An Overview

Hydrographic Confederations of Spain

Mino

The Mino originates in the Massif Galaico. Its main tributary is the Sil. It covers the provinces of Lugo, Orense, and Pontevedra, where it marks the border with Portugal. It was included in the North Basin, along with all the Cantabrian rivers.

Duero

The Duero Basin is the largest on the Iberian Peninsula. The Douro river originates in the Picos de Urbión (Iberian Mountains). It crosses the provinces of Soria, Burgos, Valladolid, and Zamora, and ends in Porto, Portugal. Its tributaries include the Esla and Pisuerga on the right bank, and the Adaja and Tormes on the left bank. It has a predominantly rainfall-fed regime, with peaks in winter and minimum flow in summer.

Tagus

The Tagus River is the longest on the Iberian Peninsula, although its basin is relatively small. It originates in the Sierra de Albarracín (Iberian Mountains). It crosses the provinces of Guadalajara, Madrid, Toledo, and Cáceres, and ends in Lisbon, Portugal. Its tributaries include the Jarama, Alberche, Tiétar, and Alagón. It has a pluvio-nival regime, with maximum flow in spring, and high and medium rainfall in the lower ocean.

Guadiana

The Guadiana River rises in the Lagunas de Ruidera and disappears underground, only to reappear later in the Ojos del Guadiana, an upwelling of groundwater. It crosses the provinces of Ciudad Real and Badajoz, and flows into the Atlantic Ocean at Ayamonte after forming the border between Spain and Portugal for a few kilometers. The Guadiana Hydrographic Confederation also manages the Tinto and Odiel rivers, which flow directly into the sea.

Guadalquivir

The Guadalquivir River rises in the Sierra de Cazorla and flows through the provinces of Jaén, Córdoba, Seville, and Cádiz, ending in Sanlúcar de Barrameda, in the Doñana marshes. It is navigable in its final stretch. Its tributaries include rivers from the Sierra Morena (Guadalimar, Jándula, Guadiato) and the Cordillera Subbética (Genil). It has maximum flow in winter and minimum flow in summer.

Segura

The Segura basin covers mainly the Region of Murcia and surrounding communities: Andalusia, Castilla-La Mancha, and Valencia. The river's flow is highly irregular, with severe droughts in summer. To alleviate water shortages in the southeast, the Tagus-Segura Transfer was built, an engineering project affecting the Tagus, Guadiana, Júcar, and Segura rivers.

Júcar

The Júcar Hydrographic Confederation manages not only the Júcar River but also the Turia and other smaller rivers that flow into the Mediterranean between the Segura and Ebro basins. These rivers are short and irregular, experiencing droughts in summer and increased flow mainly in autumn.

Ebro

The Ebro River Basin is the second largest on the Iberian Peninsula. The Ebro rises in Fontibre (Cantabria) and flows through the provinces of Burgos, Álava, La Rioja, and Zaragoza, forming a broad delta south of the province of Tarragona. Its left-bank tributaries, such as the Aragón, Gállego, Segre, and Cinca, have a pluvio-nival regime and collect water from the southern slopes of the Pyrenees. Its right-bank tributaries, such as the Jalón, have an irregular rainfall-fed regime and originate in the Iberian Mountains.