This estuary forms a great natural harbour, which became the most important seaport in the North of Spain, the estuary remaining navigable thanks to the canalisation works of Evaristo Churruca.
Today, port activities are concentrated in the external part of the estuary, where a mega-port has been developed in the last decades (at the Abra in Santurtzi). This has allowed for the dismantlement of industry and port facilities in order to recover the river banks for the leisure of the citizens. Thus, different urban development projects have been carried out in this area, and some of them are still on-going, such as the Zaha Hadid master plan for the Zorrotzaurre Island.
At the same time, a lot of energy has been put in cleaning the river, which after so many decades of intense industrial activity, had become one of the most polluted in the world.

