Monsoon fury: Changes in hill slopes by NHAI ‘behind’ landslide that killed 16 in Karnataka
Aksheev Thakur
Tribune News Service
New Delhi, August 3
The Geological Survey of India (GSI) has stated that the recent landslide in Karnataka’s Shirur was due to the modifications in the hill slopes by the National Highway of Authority (NHAI).
Following 503 mm of rain on July 16, a massive landslide destroyed a portion of the Karwar-Mangaluru 1,640-km NH-66. Over 16 people died and three went missing following the landslide.
According to the report, due to the modifications in the hill slope, the natural drainage system which could have allowed the smooth flow of water was also obstructed.
“To facilitate four-lane traffic, the hill slopes in this road section had to be modified. Satellite imagery from Google Earth shows that slope modifications have been initiated in the area since 2017, with modifications up to 40m in height. Natural drainage flows have been disturbed due to slope modifications. The steep gradient of the cut slope, presence of highly weathered rock, thick debris, saturation due to rainfall and lack of toe support are the primary causative factors of the debris flow. Intense rainfall acted as the trigger for the landslide,” the report said.
The GSI has recommended that vehicular traffic at night should be restricted.
“Refrain from removing debris material on the hillward side below the landslide for the time being. Construct temporary channels to divert water from the debris-clearing area. No further modifications should be made to the hillward slope. Continuous monitoring of the slope using spotters is crucial and vehicular movement must be halted if any slope movement is detected, especially during prolonged rainfall,” GSI said. Meanwhile, NHAI also has constituted a committee of four experts to look into the matter.
Natural drainage system obstructed: GSI
- According to the report, due to the modifications in the hill slope, the natural drainage system which could have allowed the smooth flow of water was also obstructed
- The GSI has recommended that vehicular traffic at night should be restricted. It also said that no further modifications should be done
- Meanwhile, NHAI has constituted a committee of experts to look into the matter
