The Tagus report, by Peter-Paul Schollema
The Tagus River, in Portuguese the Rio Tejo and in Spanish the Rio Tajo, rises in Spain and flows through Portugal where it empties in the Atlantic Ocean near Lisbon. With a length of 626 miles and a drainage basin of 31,505 square miles it is the longest river on the Iberian Peninsula. The size of the drainage basin is only exceeded by that of the Ebro River. The Tagus River rises in the Sierra de Albarracin of eastern Spain at an altitude of 1590 meters.
Location: Rises in Spain and flows through Portugal where it empties in the Atlantic Ocean
Length: 626 miles
Size basin: 31.505 square miles
Use of the river: The Tagus estuary is of great international interest and is the most important wetland in Portugal. A part of the area is a nature reserve under national law and is also designated as a EU Special Protection Area for wild birds, covering some 40,000 ha.
The Tagus flows mostly through semiarid lands, and government efforts have been dedicated to increasing land irrigation and creating hydroelectric power in its basin. One of the most important issues in the Tagus river basin is the use of water for river basin transfer.
Problem:
Because of the lack of sufficient water supplies al the autonomous regions in Spain are defending their own water supplies and are not planning to give up large volumes of water. The increasing number of people that live near the Tagus estuary have a big impact on the area. There is an increasing pressure on the nature, caused by the growing number of tourists. And also the improvement of the local infrastructure like the building of the Vasco de Gama Bridge is having a bad impact on the ecology in the Estuary.
Solution:
The governments of Portugal and Spain have presented a lot of new plans to improve their water management. These National Hydrological plans formed a basis for the new river basin plans for the Tagus River, which include a lot of good ideas to solve the water management problems of the future.
According to these plans the river will be used to transfer extra water to the Segura River, but the ecology of the river will also be protected.
Abstract
Tagus River from source to estuary, A literature study after the management problems of an Iberian River.
The Tagus River, in Portuguese the Rio Tejo and in Spanish the Rio Tajo, rises in Spain and flows through Portugal where it empties in the Atlantic Ocean near Lisbon. With a length of 626 miles and a drainage basin of 31,505 square miles it is the longest river on the Iberian Peninsula. The size of the drainage basin is only exceeded by that of the Ebro River. The Tagus River rises in the Sierra de Albarracin of eastern Spain at an altitude of 1590 meters.
The upper Tagus cuts into limestone rocks and flows through narrow deep canyons and abundant ravines. Near Trillo in the Guadalajara province it runs through more solid soil and rock, and its course becomes generally more peaceful. In the province of Caceres it again flows through narrow, steep-edged trenches formed by quarzites and shales. In Puente de Alcantara (near the Portuguese border) a dam has formed one of the greatest man-made lakes in Europe, with a length of 57 miles and with a capacity of 112,000,000 cubic feet. The river enters Portugal at Beira and the Sierra de Carbajo. After flowing across Portugal for 111 miles, it forms at Villa Franca de Xira the Tagus estuary, emptying into the Atlantic Ocean.
The Tagus estuary, which is one of the three most important ones in Europe, is of great international interest and is the most important wetland in Portugal. A part of the area is a nature reserve under national law and is also designated as a EU Special Protection Area for wild birds, covering some 40,000 ha.
The Tagus flows mostly through semiarid lands, and government efforts have been dedicated to increasing land irrigation and creating hydroelectric power in its basin. Major efforts to harness the Tagus and its tributaries for these purposes were undertaken from the 1960s, and by 1980 more than 60 dams had been built with a total installed power capacity of more than 1,200,000 kilowatts. One of the most important issues in the Tagus river basin is the use of water for river basin transfer. This involves the transfer of water from the Tagus basin with the Trasvase Tajo-Segura, a man made aqueduct. This artificial canal was built during the Second Republic (1931-’39) and was designed to transport water from the upper reach of the Tagus to the Segura basin in the south of Spain where it could be used for irrigation. Because of the inadequate use of the available water supplies in Spain the government presented a new National Hydrological Plan. One part of this plan involves the repair of the Trasvase Tajo-Segura and increasing the amount of water that is transported with this aqueduct.
Because of the lack of sufficient water supplies al the autonomous regions in Spain are defending their own water supplies and are not planning to give up large volumes of water.
In case of the Trasvase Tajo Segura this has led to several political discussions between the regions of Castilla la Mancha (Tagus river basin) and Valencia (Segura river basin). The Valencia region has won and the Castilla La Mancha region has to allow that large volumes of water are being transferred to the Segura river basin in the South.
The Tagus River Basin
There are also other developments that are a threat to the Tagus River. Especially the increasing number of people that live near the Tagus estuary have a big impact on the area. There is an increasing pressure on the nature, caused by the growing number of tourists. And also the improvement of the local infrastructure like the building of the Vasco de Gama Bridge is having a bad impact on the ecology in the Estuary.
During the last years the governments of Portugal and Spain have presented a lot of new plans to improve their water management. These National Hydrological plans formed a basis for the new river basin plans for the Tagus River, which include a lot of good ideas to solve the water management problems of the future.
According to these plans the river will be used to transfer extra water to the Segura River, but the ecology of the river will also be protected. The future will show if the managers of the river will be able to carry out their plans on a proper basis and protect the river for future generations.
For more information about the Tagus river the following sites can be of any interest:
http://www.mma.es - Ministerio de Medio Ambiente (MMA), the most important authority on water management in Spain and responsible for the National Hydrological Plan
http://www.hispagua.cedex.es - Information about water management in Spain
http://www.icid.org - International Commission on Irrigation and Drainage (ICID)
http://www.un.org/esa/agenda21 - Information about sustainable development of almost all the countries in the world.
http://www.lnec.pt - Laboratorio Nacional de Engenharia Civil , Dams Department, information about the storage dams in Portugal.
http://www.internationalwaterlaw.org - Information about international water treaty’s en water laws.
http://www.eea.eu.int - European Environment Agency (EEA)
|
