Gozo tunnel to produce one million cubic metres of excavated rock, study shows

Tunnel entrances are being proposed for Imbordin in St Paul's Bay and beneath the Kenuna Tower in Nadur

Under the sea: A proposed tunnel between Malta and Gozo will have one lane in either direction
Under the sea: A proposed tunnel between Malta and Gozo will have one lane in either direction

Over one million cubic metres of rock will be hauled out during the excavation of a tunnel beneath the seabed in the channel between Malta and Gozo, according to a preliminary study.

This is equivalent to more than the entire amount of construction waste disposed in a single year.

The proposed tunnel route
The proposed tunnel route

The proposed entrances to the tunnel will be at Nadur, below the Kenuna Tower and Imbordin, a hamlet between Pwales and Manikata that forms part of St Paul's Bay. The tunnel connecting both islands will bypass completely the Xemxija to Ċirkewwa stretch that forms part of the European road network.

A Project Development Statement presented to the Environment and Resources Authority identifies construction waste as one of the main environmental impacts of the project. The preliminary study will have to be followed by a full Environment Impact Study.

The preliminary study considers two options for dealing with the waste problem: disposing of the excavated rock in the sea or using the waste in land reclamation projects.

The PDS also reveals details on the route chosen for the tunnel with an entrance at Imbordin in St Paul’s Bay and another, west of Nadur in Gozo.

Choice of entrances

Imbordin was chosen as the best location for the tunnel’s entrance due to its location on a steep rock escarpment.

Malta side: Indicative tunnel entrance shown in yellow at Imbordin
Malta side: Indicative tunnel entrance shown in yellow at Imbordin

This will still require an additional road link in the ecologically sensitive area. But according to the PDS the portal is at a “short distance” to the road leading to Route 1 on the TEN-T, “thus limiting the length of access infrastructure required”.

The elevation is also very close to sea level, thus the tunnel length would be minimised.

Gozo side: Indicative tunnel entrance shown in yellow at Nadur
Gozo side: Indicative tunnel entrance shown in yellow at Nadur

The area being considered for the portal on the Gozo side is on the ridge just below the Kenuna Tower. The advantage of this location is the steep hillside. Furthermore, it is very close to Triq ir-Rabat, which makes the access from the tunnel to the connecting road network quite short.

Single-tube tunnel

The tunnel will consist of a single-tube tunnel with two lanes, one in each direction. Each vehicle lane shall be between 3.25m and 3.5m wide, and the two lanes will be divided by a central buffer area of approximately 1m width. A 1m-wide shoulder will be retained at both sides of the carriageway.

The tunnel will be operated with a remote toll system and will require no queuing areas or ancillary facilities at the entrances.

The planning and design of the tunnel is expected to take three more years. Excavation of the tunnel is expected to take three years and finishing works another year. This means that the tunnel will be developed in a seven-and-a-half-year time frame.

The timeline is still considered as a “very broad estimate”, as the actual duration of works will depend greatly on the tunnelling method chosen by the contractor, as well as the geological environment encountered during the tunnelling works.

The PDS refers to a Social Impact Assessment carried out by Marvin Formosa which found that 82% of Gozitans favour a permanent link between the two Islands.