A1 closed for weeks after River Mondego dyke breach near Coimbra

James H. Amos • August 28, 2026 08:36

A breach in a dyke on the right bank of the River Mondego has forced the closure of the A1 motorway in both directions between kilometres 198 and 189, on the stretch linking Coimbra Norte and Coimbra Sul, and it may remain shut for several weeks.

What happened on the A1 near Coimbra

The issue stems from a subsidence affecting part of the A1 carriageway platform in the north–south direction, close to where the dyke that channels the River Mondego failed, in the Casais area.

Preventive closure and safety measures

However, as a precaution, the section had already been closed at around 18:00 on Wednesday-roughly three hours before the collapse. For that reason, as stressed in a statement from BCR – Brisa Concessão Rodoviária, “the subsidence (…) did not, at any moment, represent any risk to users or workers”.

Works will take weeks

Speaking to SIC Notícias, the Minister for Infrastructure and Housing, Miguel Pinto Luz, confirmed that the Government was aware of what was unfolding and that this “problem had been monitored for several days by the National Laboratory for Civil Engineering (LNEC)”.

In the same interview, the minister described the situation as “absolutely extraordinary” and said it would take several weeks to repair the damage on what is the country’s main motorway.

“The only thing we can do while the water level does not go down” is to use compacted rock blocks to reinforce the break that has appeared in the platform, the minister said, not ruling out the possibility that the crack could spread to the opposite carriageway.

“While the water level does not go down it is not possible to carry out the fundamental intervention. It will certainly take weeks for us to get this infrastructure back in service for the Portuguese”, Miguel Pinto Luz added.

Brisa suggests alternatives

In its statement, Brisa acknowledges that, “as it is not possible (…) to estimate a completion date for the works”, motorists can use the “A8/A17/A15 corridor or the IC2” as alternatives.