How to destablize a hill in quicktime: Nursery Gaon landslides, (Kalimpong) 07Jul2020

I had visited Nursery Gaon along with GSI Geologist Debashish Bhattacharya in Dec 2012 and blogged about it. It lies below the 7/8th mile area of Kalimpong and several landslides there were active even then. Some picture posts of our visit in 2012 from the STH blog are below:

Subsequently on 01Jul2015, following heavy rainfall, a landslide occurred again at Nursery Gaon and an entire family perished. Their bodies could never be traced.

• I am very familiar with the area which lies on the western face of Kalimpong and as such is steep and mostly rocky. Compared to the eastern face, this region has sparse population but at the crest (the 8th mile area) there is a large urban build up with several prominent schools, flower nurseries and the road (State Highway -SH12) linking Kalimpong to Teesta bazar passes thru this region.

• Kalimpong has long needed a by pass road since the SH12 passes thru town and traffic snarls are increasingly becoming impossible esp when large military vehicles have to pass thru narrow areas. To obviate routing thru the congested town area, a by pass road circumventing the urban cluster was planned. This road which was to start at 7th mile, pass below the 8th mile area and terminate somewhere in Bhalukhop avoiding the entire town area.

• The by pass road was inaugurated in 2009 (to the best of my knowledge) and rather coincidentally my first record of a landslide in the region is also of Aug 2009.

• Since then I have visited the by pass area many times, to check the increasing areas of instability along the road.
• On 07Jul2020, following heavy rains, there were reports of landslides in the area. I visited the area on 10Jul2020 and this is my assessment:

Images from my survey in the area are place below:

Size of slide is approx 60m in length

The length of this subsidence is around 30-40m

RAINFALL ON 06Jul2020 : 109mm

Having talked to affected people of the area:
1. It is well known that roads interfere with the natural drainage of a mountain and therefore are a major cause of landslides. In the case of the above landslides, this is very evident. Whereas there was little instability in this region before 2009, the incidents of landslides have increased sharply over the years.
2. This was very evident even in 2012, when I visited the area and made a pointed remark that this area would be susceptible to slope failures due to poor drainage (see first slide).
3. Sure enough, on 01JUL2015 we had a fatal landslide in the area.
4. Unfortunately even after that, nothing has improved. Merely loading the area with more concrete, stone and sand is NOT the solution and perhaps the engineers will have to incorporate some innovative ideas on how to manage the water and improve drainage.
5. High time we think seriously about how to control the instability instead of how to make money from it.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

09July2019: Landslide report from Darjeeling.

Landslide in front of Anugayalaya/Divyavani, near Loreto Convent, Darjeeling

 At around 4:30 am on Tuesday Morning i.e., 9^th July, a landslide occurred in front of Anugayalaya/Divyavani near Loreto Convent (to be precise below Bishop’s House, NH10).The debris covered the entire road in front of the building which caused the drain water to enter inside the building (fig. 1.0).

The landslide took place at the adjoining road (i.e., a road to Anugayalaya’s Office) on NH10 (Lebong Hill Cart Road).There were few signs of crack visible on the road in fig 1.2. The slide is measured to be around 13 metres in height and 6 metres in width. However, to consider the width of the whole areas, is 30 metres (which is also the length of Pony road). The rainfall data as measured by IMD over the past 24 hours is 112 mm.

The staffs(Church and Anugayalaya) witnessed the incident in the morning. Around 4 am in the morning, they noticed drain water streaming down the slope and slowly leading to landslide. The slide blocked the road in front of Anugayalaya’s office, which is also a road leading to Loreto Convent.

The local residents and the staffs cleared and made a walkable passage for the school children to walk down to their school. They covered the landslide (fig 1.7). Till 9 am, no local authorities neither the relief materials were available.

The reason behind this incident was drain blockage. The drain system was completely blocked as shown in fig. 1.4, 1.5 and 1.6. So, the drain water along with road/rain water started flowing/pouring down the slope causing landslide.

The authorities started to visit the site after 9:30 am. The Irrigation department came to take measurements then followed by the traffic officials. Assistant Engineer Mr Anup Das, Central Planning, GTA visited the site as well.

The Darjeeling municipality engineer department, Mr Prashant Rai (Head of the engineer department) visited the site. He informed his department workers to come and start cleaning up the debris. The workers started cleaning the road as seen in fig 1.8, 1.9 and 2.0. The clearance took till 1:30 pm in the afternoon. 

Amit Gurung
SaveTheHills
Darjeeling

Killer landslides of the future : Darjeeling (30May2013)

"I fear that we will see a legacy of landslides in the urban areas of Asia over the next decade as a result of the incredible rate of urbanization in Asia." -  Professor Dave Petley, BSc (Hons) AKC PhD FRGS FGS ILTM CGeo, Univ of Durham (UK)

 

Rain Death : an excerpt from The Telegraph (31May2013)

Darjeeling, May 30:

Subhawana Chhetri, 21, was killed when a wall collapsed during heavy rainfall at Himali Goan in Singamari near here around 2pm today. “She was trying to fill up a drum with rain water when a retention wall collapsed and she came under it,” said a relative.

A student of Loreto Convent, Sheetal Thapa, 17, was injured in a mudslip at Rose Bank. “The Class XII girl was partially buried in a mudslip when she was on her way to school around 7.30am. Local people pulled her out,” said an official of the district administration.
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Comment by Praful Rao, Kalimpong

The fatal landslides shown above are now a familiar sight ( see 1 and 2) :-
Their characteristics are :-

a) They are relatively small landslides or slips.

b) The human footprint is writ large in the cause of the slides - most often they are caused by faulty drainage or lack of any drainage.

c) They take place in an urban setting like the one seen above.

d) They kill people.

e) We can do a lot to mitigate or prevent  these killer  landslides but tragically no one is really bothered.
f) What is scary is that the monsoons have not even reached us (officially they should be over us on 05Jun2013) and we have at least 4 months of rain ahead of us!

• Photo credit : Sanjit Nandi, Himalaya Darpan