STH Activities : Landslide Survey on the eastern flanks of Kalimpong (14July2016)

 14th Mile Landslide

The 14th mile 'sinking zone' lying on the eastern face of the Kalimpong ridgeline is one of the old landslide areas of this town. It is repaired on annual basis and is rumored to be a "blessing" to many a contractor - except that now with population growing and even a posh hotel coming up directly above this site, it will also be a curse to quite a few.
When I visited the site on 14Jul2016, I found that a portion of the road to Algarah had sunk considerably (slide 'A') and worse still the culvert next to it had also sunk (slide 'B') - and ALL the water from the culvert was percolating into the crack (slide 'C') acting as a lubricant to an unstable hillside ready to slide down.
Coordinates :
27°05´27.6” N

088°31´57.0”E
Elevation : 1372m

Landslide blocking Kalimpong - Lava Road

With our main road to the external world, NH10 always in a precarious state during the monsoons, we rely on the Kalimpong- Lava- Gorubathan road as our an alternate route to the plains. Unfortunately, this road also has quite a few 'hotspots' which keep the BRO busy during the monsoons.
On Sunday, 10July2016 at around 1600h, following the 125mm rainfall of Saturday, a portion of this road near Rickisum gave way. It remained blocked for 4 days and effectively cut off Lava and much of the eastern parts of sub-division from Kalimpong town.

Coodinates :

27°05´49.5”N
088°36´22.6”E
Elevation : 1804m

Praful Rao,

Kalimpong,

Dist Darjeeling

Impact of humans on landslides : 14th Mile landslides (Kalimpong) in 2002 and now (2015).

The 14th Mile landslides (top) or sinking zone is one of the oldest in Kalimpong and has been featured in this blog earlier
Placed above are 2 Google Earth images of the same landslide zone of 2002 and 2015.
Both are photos were taken in January and the areas numbered 1 and 2 show significant increase in human habitation in the intervening 13yr period between the two photos.
Site 3 shows the 14th Mile landslides which are much bigger in the 2015 image even though we have had deficient rainfall in Kalimpong for 3 consecutive years from 2013 ie we are seeing an increase in landslides even though there is a decrease in precipitation (rainfall data of this region for the last three years is documented month-wise elsewhere in this blog).
Without being overly simplistic, as human activity grows along mountain crests, surface run-off of rain water from paved areas sharply increases the torrents of water charging the mountain streams or jhoras, leading to higher levels of erosion and landslides.
Increasingly, human activity is therefore emerging as a major cause of landslides in the mountains and is undoubtedly the main trigger for all fatal landslides that have taken place in Darjeeling-Sikkim in the recent past.
While it is well within our reach to control these actions and mitigate the landslides, neither the community nor the government (includes politicians) are bothered.

Praful Rao,
Kalimpong,
Dit Darjeeling