Wednesday, March 29, 2023

SaveTheHills survey of landslides near Dikchu (East Sikkim) on 27Mar2023



Following media reports on a major landslide occurrence at Sokpay, near DIKCHU on 26Mar2023, we made a quick visit to the region the next day. Our report:

Rainfall data for the month of MARCH of Mangan (District HQ of North Sikkim)
2021 - 249.9mm
2022 - 166.5mm
2023 - 272mm (upto 28Mar2023)
Dikchu is situated approx 2.5km (approx 21km by road) south of Mangan.

Location and Co-ordinates of the base (toe) of landslide
The landslide at Sokpay (Rakdong-Tintek block) is huge with the crown located at least 1500' above the toe. We could only survey the base (toe) of the landslide which is located very close to DIKCHU town because the landslide has cut off access to the higher reaches where several affected homesteads are located.
Co-ordinates and elevation: N27° 23.822' E88° 31.142'
Elevation: 2543ft (775m)

Brief history and date and time of occurrence
As per locals, the landslide at Sokpay took place between 3-4am on 26Mar2023.
However, they trace back the instability to 2016 when there was a landslide in the area and thereafter, smaller landslides taking place at regular (even yearly) intervals; with 'surveys' being conducted and talks of relocation also taking place but nothing being implemented.

Probable cause
This seems to be a mystery since there has been very little rainfall in this region since Oct2022. In Mar2023, Mangan and Gangtok region did receive 'excess' rainfall (see below)
But this amount and intensity of rainfall, in our experience does not trigger such a large landslide. Local people are quick to point out that it is NHPC's Stage V Dam on the Teesta river located at Dikchu as a cause and also the large power towers (pylons) at the top (crown) of the landslide as the probable trigger.
However, there is no study done to prove this.
Government officials are equally fast in saying the entire investigation is being done by the Department of Mines and Geology, Govt of Sikkim and that their report on the cause and remedial measures to be taken is awaited. They also point out that this area is landslide prone with many sinking zones - which even a cursory look at the region will prove as correct.
We also found no other evidence of large scale and recent human interference such as road/tunnel construction which could have triggered the landslide. Nor was there any erosion by a jhora or river in the close vicinity which could have caused erosion and triggered the  landslide which started from the hilltop.

Casualties and damage
There were no human lives lost even though the farmers lost cattle and pigs in the slide. 4 homes were totally damaged and 20 families have been shifted to temporary relief shelters by the government. Unlike the landslide in Pathing, both the media and government authorities seem to have mobilized immediately. The Government has implemented relief measures and also taken the help of the Power Companies to provide temporary rehabilitation to the affected families.
Road communications from DIKCHU to GANGTOK has snapped and the main road from DIKCHU to MANGAN may also be affected in case the landslide is reactivated during the oncoming monsoons.




We discovered this landslide at Tumin Shelay, in the same area almost by accident. This huge landslide is more than a year old and seems to have been triggered by rain in an agricultural area. The farmers have lost almost 3 acres of paddy field there and around 3-5 families have been compelled to relocate. A local person guided us to the landslide which has affected the lives of the farming community in more ways than one - tourism which was coming up around a beautiful waterfall in the vicinity has died a premature death.
Like many landslides which occur in remote areas, this one never hit the headlines - in fact, I had never even heard about it, until we reached the place searching for the recent DIKCHU slide.

Location and Co-ordinates of landslide
Located at Tumin Shelay village.
Co- ordinates near the crown: N27° 19.492' E88° 30.134'
Elevation: 4082ft (1244m)

We will be uploading a short documentary, on our visit to these landslide sites. The documentary will include interviews, images and drone footages of the landslides.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

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