NOTE about Tagus river and estuary
The Estuary of
Tagus is one of the largest in Western Europe. It has an area of
325 km2 and is one of the 10 more important humid areas for
birds in Europe, being endangered by
industry and urban pressure. It
has an average of 1900 million m3 of water and a
saline intrusion occurs
until about 20 km from Lisbon. The amplitude
tides in Lisbon varies between
m and 1,2 m. In terms of mixture of saline water it is partially stratified.
The average flow of the river is 400 m3.s-1,
between 100 and 2000 m3.s-1, according to the
(during flooding it had a recorded flow
of 14 000 m3.s-1). The total area of the
watershed is 630
km2, being 31% in Portugal and the remaining
69% in Spain.
length is 1070 km.
geology of the
low Tagus valley is very complex. The last
manifestations occurred 80 million years ago. During the quaternary
last 2 millions of years) there were several big oscillations in the
(more then 60 m, due to glaciations) and a big variety of flora and
developed in the area.