Sta Venera tunnel leak remains a mystery

The source of the intermittent leak in the Santa Venera tunnels has not yet been found.

The leak appears about 100 metres into the northbound tunnel and because it comes right after a dry road, it is “an unnecessary hazard to motorists”, according to The Sunday Times Motoring editor Matthew Naudi.

On September 29, the tunnel was closed for two hours after water started pouring from the ceiling. The following day, with no intervention from the Water Services Corporation, the leak stopped abruptly, only to start again in December and then stop again a few days ago.

The problem, however, remains, as the source of the leak is still unknown.

When contacted, neither the WSC nor Malta Transport had an explanation for it. Both have carried out tests to establish where the water is coming from but the results have proven to be inconclusive.

Chemical tests by the WSC established that the water leaking into the tunnel was “considerably different” from that in the mains or drainage pipes running in the area and even differed from two private boreholes nearby; one near the Fleur-de-Lys roundabout and another one in Triq Antonio Miruzzi. The WSC said it could be “contaminated rain water that is somehow finding its way through fissures above the tunnel”.

Meanwhile, a spokesman for the transport authority, which is responsible for the tunnel, said tests carried out on water culverts showed the fluid was not coming from there either.

The transport regulator ruled out that the fissures could be a threat to the tunnel. “Malta Transport has engaged the services of a structural engineer to assess and closely monitor the structural stability of the tunnel. The fissures are not a threat to the structural integrity and stability of the tunnel.”

But surely having a patch of water in the middle of a tunnel is an added risk for motorists?

Malta Transport disagreed, saying “the leak is currently an inconvenience rather than a danger per se” and that the situation would only become a dangerous one if one were to block the leak by sealing the fissures and allowing water to accumulate.

While it did not commit to any lasting solution to the problem, Malta Transport said it was considering installing a gutter that would divert the leak to the sides of the tunnel rather than letting it drip vertically.

In October, a spokesman for the WSC had said that if the source of the leak was not identified by the end of October, the authorities would consider at-taching a water catchment system to divert the leak to drainage channels running along the tunnel’s sides.