Morocco-Spain undersea tunnel proposals to be assessed

A German company has been tasked with conducting a feasibility study on the visionary proposals for an undersea tunnel connecting Morocco with Spain.

According to the Arabian Gulf Business Insight on January 22nd, Spain has hired Herrenknecht Iberica look at the long-aspired plans of a tunnel beneath the Gibraltar straight.

The proposed route, the Ruta de Umbral, is 38.5km, 28km of which would be under the sea, making it one of the longest of its kind.

Some stages would be up to 475m below sea level.

The Channel Tunnel, between the UK and France is currently the longest undersea tunnel at 50km, with a 38km stretch below water.

However, its deepest section is only 75m below sea level, paling in comparison to the hefty depth requirements of the Gibraltar crossing.

The deepest undersea tunnel in the world, the Norwegian Ryfast tunnel, is only 292m at its maximum depth, according to Campervan Norway.

Opening in 2019, construction took 6 years and was estimated to cost $460m.

Ryfast is only 14.3km long, thus costs would seem for the proposed Ruta de Umbral to be on another level, with the Moroccan National Company for Strait Studies placing the price for a railway tunnel at $6bn, according to the New Civil Engineer.

Both Morocco and Spain eye the project, that could have an estimated 12.8 million passengers annually, as a potential asset in the 2030 World Cup, which is jointly being held by them and Portugal.

The tunnel was mothballed in 2009 but revived in 2023, when the joint Spanish-Moroccan commission for the undersea tunnel project met for the first time in 14 years.

Studies for the crossing date as far back as the 1930s, when Spain hired engineers to study the route.

The discovery that the rock under the straight was too hard for the tunneling technology of the time to penetrate, led to a proposal to attach a prefabricated tunnel to the sea floor.

Difficulties compound when considering the presence of a major geologic fault, the Azores–Gibraltar Transform Fault, which has caused earthquakes in the region.