The regional government of Aragon, in northeastern Spain, called the march, supported by local trade unions and employers organisations.

"Aragon, water and a future!" demonstrators chanted in protest against the plan designed to channel more water to Spain's parched Mediterranean coast, whose economy is partially based on intensive greenhouse farming which requires constant irrigation.

The water would be diverted from the Ebro river delta, which flows through Zaragoza.

"There are better and more economically sound solutions than diverting (the river), which is stupid," said the socialist president of the Aragon government, Marcelino Iglesias.

Iglesias accused the central government of "perverting the bounds of solidarity" by claiming to "plunder" a less rich region like Aragon "in favour of Spain's more developed regions."

The right-wing government in Madrid wants Brussels to put up a third of the 4.2 billion euros (4.9 billion dollars) the scheme is expected to cost over the next 25 years.

But the European Commission -- the EU's executive arm -- is hesitant because of the damage the scheme could inflict on the environement and the water price mechanisms the government intends to introduce.

Ecologists are also fiercely opposed to the plan, which foresees the transfer of more than 100 million litres (around 22 million gallons) of water every year from the Ebro delta between Valencia and Barcelona to the arid southern and eastern coastal zones.

It involved the construction of hundreds of kilometres (miles) of water channels.

TERRA.WIRE