Morocco-Spain Underwater Tunnel Project Faces Major Engineering Challenges

"As an engineer who has worked on many large-scale infrastructure projects, I’ve seen what it takes to turn ambitious ideas into concrete realities. And this one is, without a doubt, among the most daring. [...] An underwater tunnel between Europe and Africa would be a historic engineering feat, but it would be anything but easy to build," comments Bill Bencker, a construction specialist, in an interview with the British newspaper L’Express. According to him, there are prerequisites, including determining the exact route of the alignment before even considering the start of construction. The most logical option would be to cross the Strait of Gibraltar, the maritime passage that separates Spain from Morocco, he estimates.

According to the expert, one of the major difficulties is that beneath the surface, the strait hides abyssal depths, reaching more than 900 meters in places. Drilling a tunnel under the seabed becomes infinitely more arduous than for the Channel Tunnel or the Laerdal Tunnel. "Because of these extreme depths, a traditionally bored tunnel under the seabed would be of daunting complexity," explains Bencker. He proposes as an alternative a submerged floating tunnel, suspended underwater by cables anchored to the seabed. He also suggests a hybrid system combining excavated underground segments and others resting on infrastructure laid on the bottom of the strait.

Another major challenge is the duration of the construction of such a tunnel. "If you imagine that this tunnel could come to fruition in a decade, you’re mistaken, warns Bencker. A project of this magnitude would require between 15 and 25 years between the preliminary studies and its completion." He adds: "And it’s not just the construction that would take time: the real bottlenecks are the feasibility studies, environmental assessments, securing financing and political agreements."

The expert further explains: "Even if the negotiations started tomorrow, it would take years of geological surveys and experimental modeling before the first concrete pour is made." He continues: "Then the construction phase itself would be extremely slow, facing the challenges of underwater work: abyssal pressures, tectonic movements and hostile weather conditions."

The overall cost of the project is the other major challenge to be met. Estimates range from 540 to 1,080 billion dirhams (£42 to £84 billion), depending on the type of infrastructure chosen, Bencker says. Compared to the Channel Tunnel, which was much simpler to build, and cost the equivalent of 150 billion dirhams (£11.7 billion) taking inflation into account, the budget is colossal.

"And with a project of this magnitude, cost overruns are inevitable," the expert points out. "Unforeseen geological conditions, fluctuating material prices or diplomatic deadlocks could further explode the costs." Nevertheless, this project is feasible. "In short, it’s a viable project, but one that promises to be a path strewn with pitfalls. Between the cost, diplomacy and technical challenges, it will take a colossal commitment from the Spanish and Moroccan governments as well as private investors to ever hope to see this tunnel become a reality," Bencker concludes.