Has anyone realized that the Rio Tejo is one of the largest highways in the country?

True, water-borne shipping requires its own fuel, but what is preventing Portugal in particular from developing an ad hoc river transport network even if to just get raw meat and other foodstuffs into town?

I ask partly because I live in Monterey, California, just blocks from the oldest port in the state. Every time I pass it I realize that for most of our 240 year history that was how trade was conducted - by water. We need to rebuild our rail network as well, but it seems that water transport could be a viable method of moving goods, even if it cannot replace trucks or rail freight.

Something to think about, if nothing else...

And the world will live as one