Basin The Tagus basin has a total area of . It is the most populated basin in the Iberian Peninsula, with more than ten million inhabitants. It includes the Madrid metropolitan area and the Lisbon region. The Tagus basin has a total reservoir capacity of around .
basin the tagus basin has a total area of  it is the most populated basin in the iberian peninsula with more than ten million inhabitants it includes the madrid metropolitan area and the lisbon region the tagus basin has a total reservoir capacity of around 