India's sixth longest rail tunnel for Vizhinjam port, MoEF drops most objections

The Ministry of Environment and Forests and Climate Change (MoEF&CC) has toned down its objections to the 9.46-km underground rail tunnel that would connect the Vizhinjam International Seaport to the Southern Railway network.

Last September, the Expert Appraisal Committee (EAC) of the MoEF&CC viewed the shift of the rail line from over to underground as a radical change in project design that called for a new Environment Clearance (EC).

The EAC had refused to accept the proposal of Vizhinjam International Seaport Limited (VISL) seeking a mere amendment to the EC that was already secured for the Vizhinjam project in 2014. The EAC had observed that the change in design had altered the "scope of the project" and wanted the VISL to apply for a fresh EC.

It also sought a long list of clarifications from the VISL on the underground rail project including flood risk, vibration impact, rainfall intensity, coastal regulation zone (CRZ) implications and hydrogeological conditions.

The EAC even hinted that the area where the underground tunnel was proposed was a seismic zone. "The topography is highly undulating both in the sedimentary and crystalline outcrops indicating the presence of large-scale tectonic deformation took place in the geologic past," the minutes of September 15, 2022, meeting said.

Sudden change of weather
However, when the EAC met in the last week of March this year, it looks like most of the concerns it had raised last September have been satisfactorily addressed in the Environment Impact Assessment (EIA) prepared by the project's EIA consultant L&T Infrastructure Engineering Ltd., Hyderabad.

Clearly, the EAC has dropped its earlier insistence on a fresh EC. There is no mention of the "change of scope" in the March minutes of the EAC meeting.

On the other hand, there is an unmistakable hint that the amendment the VISL has sought in the original EC would be granted.

For the moment, the approval has been withheld. It will be given once the project proponents will have conducted two more studies.

Internal threats
One, vibration studies. The EAC observed that the vibration studies it had suggested in September for the stretch of the railway line which is passing underground through inhabited areas have not been conducted. Last September, the EAC expressed its worry about the impact of the tunnel and its operations on aquifers and aquatic life underground and residential and commercial buildings above the ground.

At about halfway in the tunnel, the railway alignment will stumble into an underground pond. The Adani Vizhinjam Port, in its latest compliance report, has stated that the pond would be "excavated partially" and the soil material would be used to reinforce the western part of the tunnel.

By asking for a vibration study, it is evident the EAC was not convinced.

Two, assessment of subsidence risk. Subsidence is a geological phenomenon that refers to the sudden vertical sinking of the earth's surface. The EAC has asked VISL to employ an "institute of repute" to study subsidence-related risks.

Both subsidence and vibrations have been marked as major concerns especially because the overburden, or the thickness of soil above the tunnel, is just 10 metres over most places. This is far less than the length of the penalty line from the goalposts (16.5 metres) on a football field.

India's 6th longest tunnel
The total proposed rail length is 10.70 kms, of which 9.43 kms will be underground and the remaining 1.20 kms above the ground. Once realised, the Vizhinjam Seaport tunnel will be the sixth longest rail tunnel (9.43 kms) in the country. The longest is Devprayag Rail Tunnel in Uttarakhand, which is 15.2 kms long.

The underground tunnel will pass through the villages of Balaramapuram, Pallichal, Athiyannur and Vizhinjam. Nearly 1 km at the Vizhinjam end falls within the CRZ. However, Kerala Coastal Zone Management Authority (KCZMA) has not raised any objections.

According to VISL documents, an underground design was opted to keep the resettlement and rehabilitation requirements to the minimum. There is no need to acquire the land above the tunnel on which there are many buildings, including three-storeyed ones, in addition to coconut groves and homestead gardens. Four religious structures will also be spared.

Konkan Railway Corporation Limited (KRCL) will execute the project, which is scheduled to begin in June this year.