Multiple cracks, landslips pose major threat to Renging village

[ Amar Sangno ]

ITANAGAR, 15 Sep: Multiple cracks and landslips in and around Renging village of East Siang district are reportedly posing grave danger to the sparsely populated village.

Sources at Renging village informed that there is growing fear and restlessness among the villagers ever since the ground cracks and landslips reappeared on upslope of the village in July this year.

Two geologists from the Geological Survey of India (GSI), State Unit- Sachin R, who is also the director of GSI SU, and Manoj Kumar Sahu – had carried out an assessment in the affected areas of the village on 20 and 21 July on request of the state Director Disaster Management.

In its report, the GSI observed that ‘the geotechnical assessment of the landslide site studies indicate that the area is the ‘site of a pre-historic landslide and Renging village is situated over the accumulated debris material of the pre-historic slide.’

It added that ‘severe erosion along the nalas on the steep slope occurs during heavy rainfall. The slow creep has resulted in smaller landslides within the slide debris material over the years.’

“The slide is of about 200 m in length and has a maximum width of about 80 m. The depth of the scarps varies from 10 m to less than 10 cm at the flank ends. Issuance of springs has been observed at the flanks of the crown portion. Minor scarps of about 2-3 m are observed 30 m down slope of the crown,” the GSI added.

It further mentioned that ground subsidence, ground cracks, piping and issuance of springs have been reported from at least 1950 to the present day as per information gathered from the local people. During the second week of July, two landslips have been reported, both of which occurred due to the retrogression of earlier landslips within the accumulated debris material, the GSI stated.

“Ground cracks developed during 2016 and 2019 were also traced for more than 250 m and are situated about 150 m upslope of the village. The road in the area shows signs of subsidence, and subsidence cracks were noticed in 2016 and 2019 also. All the cracks had reactivated during July 2021 and fresh displacement up to 1 m has been observed along the cracks,” the GSI observed.

The geologists further claimed that causative factors of the ground cracks were because of the area being the site of a major palaeo slide and Renging village is situated on the loose and less compacted debris (zone of accumulation) of the prehistoric landslide.

“The accumulated debris zone has been subjected to numerous smaller landslides over the years due to the erosion at the toe of the mid-slope by perennial nalas during heavy rains resulting in creep of the entire mid-slope,” it said.

“The presence of thick overburden material, saturation of the overburden material during heavy rain and erosion, and toe cutting by the seasonal nalas during monsoon period are causative factors,” the geologists stated in their report.

As short-term remedies, the GSI suggested periodic monitoring of the ground cracks developed upslope of the village, and relocation of the houses and buildings located in close vicinity of the affected area to a safer place if the existing cracks widen or some new cracks develop upslope of the village. It also suggested backfilling of the existing cracks above the village with some impervious material to prevent the rain water from entering the cracks.

The domestic discharge should be arranged properly with lined drain and water logging should be avoided. However, it observed that for long-term stabilization measures, detailed geological mapping and geotechnical evaluation is required.

“Rainfall means nightmares and sleepless nights for the villagers. People are in fear of being swept away by the landslide as ground cracks appear everywhere in and around the village” said Dugra Paron, an ex-ASM of Renging village.

Reportedly, as a preventive measure, the district administration had asked the people of Renging village to relocate and shift from the present site. However, the villagers have not shifted as many of them are reportedly skeptical about relocating.

Local MLA Kaling Moyong, along with Deputy Commissioner Kinny Singh and the Pasighat DDMO had also visited Renging on Tuesday and had a public meeting with the villagers.

“We have identified three locations for shifting. However, many villagers do not want to leave their houses and livestock despite knowing that it is dangerous to stay in the village,” Paron added and appealed to the state government to look into the plight of Renging village.

“The cracks have reached the school and we cannot send our children to school now. But we also do not have any sources to build a new school building,” he said, seeking the government’s attention.

He also said that “It would not be possible for the villagers to build new houses at a new location, which is why they are reluctant. If only the government could step in to extend help before catastrophe strikes.”

Renging village comprises 32 households with a population of 247.  Historically, people of Renging village are believed to have migrated from Kebang village of Siang district between the early 1870s to the late 1880s.