From UPSC perspective, the following things are important :
Prelims level : Brahmaputra River
Mains level : Flood management
Disaster struck Dima Hasao, central Assam’s hill district, in mid-May after incessant heavy rainfall.
Impacts of the disaster
- The 170 km railway line connecting Lumding in the Brahmaputra Valley’s Hojai district and Badarpur in the Barak Valley’s Karimganj district was severely affected.
- The Assam government and Railway Ministry’s assessments said the district suffered a loss of more than ₹1,000 crore, but ecologists say the damage could be irreversibly higher.
How severe has the rain been in Assam?
- Assam is used to floods, sometimes even four times a year, resultant landslides and erosion.
- But the pre-monsoon showers this year have been particularly severe on Dima Hasao, one of three hill districts in the State.
- Landslips have claimed four lives and damaged roads.
- The impact has been most severe on the arterial railway, which was breached at 58 locations leaving the track hanging in several places.
- The disruption of train services, unlikely to be restored soon, has cut off the flood-hit Barak Valley, parts of Manipur, Mizoram and Tripura.
Why is the railway in focus post-disaster?
- Dima Hasao straddles the Barail, a tertiary mountain range between the Brahmaputra and Barak River basins.
- The district is on the Dauki fault (the prone-to-earthquakes geological fractures between two blocks of rocks) straddling Bangladesh and parts of the northeast.
- British engineers were said to have factored in the fragility of the hills to build the railway line over 16 years by 1899.
- The end result was an engineering marvel 221 km long over several bridges and through 37 tunnels, laid along the safer sections of the hills.
A faulty experiment
- A project to convert the metre gauge track to broad gauge was undertaken in 1996 but the work was completed only by March 2015 because of geotechnical constraints and extremist groups.
- The broad-gauge track was realigned to be straighter, but a 2009-10 audit report revealed that the project had been undertaken without proper planning and visualisation of the soil strata behaviour.
- The report gave the example of the disaster-prone Tunnel 10 on the realigned track that was pegged 8 meters below the bed of a nearby stream.
Is only the railway at fault?
- There is a general consensus that other factors have contributed to the situation Dima Hasao is in today.
- Roads in the district, specifically the four-lane Saurashtra-Silchar (largest Barak Valley town) East-West Corridor, have been realigned or deviated from the old ones that were planned around rivers and largely weathered the conditions.
- The arterial roads build over the past 20 years often cave in and get washed away by floods or blocked by landslides.
- Shortened cycles of jhum or shifting cultivation on the hill slopes and unregulated mining have accentuated the “man-made disaster”.
- Massive extraction of river stone, illegal mining of coal and smuggling of forest timbe has led to the disaster.
- These activities have increased water current besides weakening either side of riverbanks.
How vital are the rail and highway through Dima Hasao?
- Meghalaya aside, Dima Hasao is the geographical link to a vast region comprising southern Assam’s Barak Valley, parts of Manipur, Mizoram and Tripura.
- Moreover, this track is vital for India’s Look East policy that envisages shipping goods to and from Bangladesh’s Chittagong port via Tripura’s border points at Akhaura and Sabroom.
- These are the last railway station near the Feni River that serves as the India-Bangladesh border.