Tagus Segura Canal
The Tajo-Segura Canal (Spanish: Trasvase Tajo-Segura , trasvase = diversion) is the largest hydraulic engineering project in Spain to date . It is intended to increase the water supply on Spain's southeast coast in the Murcia region .
history
The first plans go back to 1933. However, construction could not begin until May 1966. Since 1979 the canal has passed numerous aqueducts and tunnels over a total length of 286 km (including that of Talave with a length of 31 km). To overcome the watershed, complex pumping systems have to lift the Tajo water from 642 m to 898 m.
The canal begins in the Castilla-La Mancha region at the Bolarque Dam , where the Guadiela flows into the Upper Tagus ( 40 ° 21 ′ 42 ″ N , 2 ° 49 ′ 13 ″ W ). It runs in a predominantly southerly direction and ends in the Murcia region in the Talave reservoir ( 38 ° 31 ′ 10 ″ N , 1 ° 54 ′ 0 ″ W ) of the Río Mundo , which later flows into the Río Segura .
The Tajo-Segura Canal is designed for a maximum capacity of 33 m³ per second. This corresponds to a maximum transfer capacity of 1000 hm³ of water per year. In 1971 the transfer of 600 hm³ per year was approved. With a calculated evaporation loss of 15% (90 hm³), 510 hm³ remain for distribution per year. The lion's share of 400 hm³ per year was intended for the irrigation of agricultural crops.
This transfer volume, which is planned as the first expansion stage, has only been achieved once (1999/2000). In the drought year 1994/95 only 135 hm³ were transferred. The hydrological calculations for the Tajo-Segura Canal are based on mean values from 1930 to 1960. In the case of the series of measurements of the Tajo water level, a period with above-average precipitation and runoff values was recorded, which has not been achieved since then.
Seawater desalination plants have also been built to supply urban households, especially in the tourist centers on the coast between Alicante and the La Manga del Mar Menor recreation area .
consequences
The initial miscalculation has major consequences for those below the Tajo River. Before the extraction, the mean runoff at Aranjuez ( Madrid province ) was 30 m³ / s in summer, the annual mean was 150 m³ / s. Now that up to 60% of the water has been withdrawn from the upper reaches, the specified minimum discharge of 6 m³ / s is no longer achieved in individual years. This means that the relative pollutant input from the greater Madrid area into the middle reaches of the Tagus has assumed alarming proportions. In the Jarama , which feeds the wastewater from the Madrid region to the Tagus, the ratio of clean water to contaminated wastewater is currently (as of 2008) 3: 7. In the section, the Tajo water is so heavily contaminated in phases that it is no longer even suitable for agricultural irrigation.
Spain's water management is a controversial issue both within the country and within the European Union . The question of the central state (as the legacy of the Franco dictatorship) is discussed in contrast to the new spirit of regionalism by means of the "old" and the "new" water culture.
Web links
Individual evidence
- ^ Hernández Soria 2001: El Trasvase Tajo-Segura. Lecciones del pasado
- ↑ Cf. Francisco Javier Martínez Gil: La nueva cultura del agua en España. Bilbao, 1997 ISBN 84-88949-16-2
Map with all coordinates: