Gallego River
The Gállego (in Aragonese Río Galligo) is a river in the Iberian Peninsula that flows through the Spanish autonomous community of Aragón. It is one of the main tributaries of the Ebro. It drains a basin of 4008.8 km² and is 193.2 km. The area of the watershed is around 4000 km².
The curious name of this river derives from the Latin name of its place of origin, Gaul: the Gallicus, the Gállego.
Geography
The river Gállego rises in the Pyrenean Col d'Aneu, at an altitude of 2,200 meters, in the vicinity of the Portalet pass. It makes its way through the Tena Valley, passing through the municipalities of Sallent, Panticosa and Biescas, cutting through the outer sierras at the Foz de Santa Elena.
The upper basin is where it receives the main tributaries: the Aguas Limpias river (regulated by the Sarra reservoir), Caldarés, Escarra, Lana Mayor and Aurín, which largely determine the flow and characteristics of the river. Gallego river. In the middle and lower basin, the Guarga, Seco, Asabón and Sotón rivers provide little flow. The course of the river is regulated by the hydroelectric reservoirs of Gállego, Lanuza, Búbal, Sabiñánigo and the irrigated ones of La Peña and Ardisa, from which water is derived to the La Sotonera reservoir through the Gállego channel (90 m³/second).
This upper course, between the Lanuza and Búbal reservoirs, are the narrow Escarrilla and Costechal gorges, separated by the mouth of the Escarra river, both favorable for the development of canyoning. Whitewater canoeing is practiced in its upper section, as is the case in its tributaries, the Caldares and the Escarra.
From Sabiñánigo it begins to describe a wide bend to Triste, from where it continues again its original N-S direction to not leave it until it joins the Ebro river, near Zaragoza.
Downstream from the Ardisa reservoir, in the municipality of Puendeluna, it derives from a dam from which the canal leaves, which, passing through the towns of Puendeluna and Marracos, supplies water to the Salto del Lobo power station to then rejoin its flow to the river. It is an area where the practice of canyoning and rafting reaches its maximum development near Murillo de Gállego, downstream of the La Peña reservoir, an area in which it makes an important contribution to the local economy.
Downstream from this point begins the Bajo Gállego. The channel meets new dams, such as Ontinar or Rabal, which feed the irrigation systems of the Camarera, Urdán, or Rabal canals. It is a protected area as a special conservation area for its value as a natural corridor.
The flow of the Gállego at its mouth in Zaragoza is weak; The intense regulation and flow derivations cause its current average flow to represent 10% of its natural flow.
Environment
Ribera de Biescas
The head of the river is protected as a special conservation zone (ZEC) for its environmental value.
Pollution in Sabiñánigo
The river suffered a significant environmental impact due to a significant spill of lindane by a pesticide company, contamination that affected part of the municipality. Official sources have estimated that between 1975 and 1989 between 115,000 and 160,000 tons of toxic waste were dumped from two dumps in Sabiñánigo, which somehow partially leaked into the river.
Lower Gállego
The stretch of riverside groves from Gurrea de Gállego to Montañana, where the anthropized area begins in the urban environment of Zaragoza, forms a second protected zone as ZEC due to its value as a biological corridor that unifies other environmental zones.