What caused landslides in Kodagu?

By Kishor Cariappa

MADIKERI: A month after Kodagu was devastated by unprecedented floods and landslides, questions are being asked about what could have led to the worst natural disaster to strike the tiny district in Karnataka in decades.

While rampant deforestation in the name of tourism has been blamed primarily for the tragedy, experts state there are other reasons that could have contributed to the calamity.

In this article, we look at some of the possible causes that led to the widespread disaster.

Deforestation
We all know Kodagu has been witnessing a tourism boom for the last 10 years, and to attract tourists, new resorts and homestays were constructed along the landslide-affected areas of Tantipala, Mukkodlu, Hattihole, Megathalu, Yemmethalu, Hammiyala, Kaloor, Monnangeri and Jodupala.

The landscape around these places, which encompasses moderately sloping structural hill ranges, have reduced green cover owing to commercial activity. This made some of the places every susceptible to landslides. Earlier, the same slopes were covered with thick green cover which ensured minimal soil erosion and landslides.

Heavy rains
Breaking the 87-year-old record (set in 1931), Kodagu received the highest-ever rainfall in August this year. Data for the first three weeks of August 2018, shows Kodagu received 1,675 mm of rainfall which was way above the mark of 1,559 mm of rainfall in 1931. Data from the Indian Meteorological Department (IMD), Bengaluru, shows that 45 per cent (or 768 mm) of the rain in August fell on just three consecutive days — August 15 (206 mm), August 16 (262 mm) and August 17 (300 mm). Extreme rainfall during the three days led to landslides and tragedy. Intense rainfall, coupled with last several years of commercial exploitation of land in the affected villages, compromised the land’s ability to cope with heavy rains and greatly increased the magnitude of the suffering.

Tremors
Worst-affected villages in the Somwarpet and Madikeri taluks — Tantipala, Mukkodlu, Hattihole, Megathalu, Yemmethalu, Hammiyala, Kaloor, Monnangeri and Jodupala — recorded mild tremors on July 9 this year. High intensity rains and the topography which was weakened by tremors also led to landslides.

Harangi dam
The backwaters of Harangi dam, which has been constructed at such a vulnerable confluence, is causing pressure and punch in all the veins of perennial water flows at the nerve centres in the affected villages that are situated in the backwaters of the dam. Due to constant pressure, the nerve centres of water spring and the veins were punctured. This resulted in massive landslides. Some reports say wherever there is a reservoir close by, tremors will be followed by landslides in the surrounding regions.

Water tanks
Coffee estate owners in the affected villages had constructed massive ponds to store rainwater water for irrigation purposes. Due to heavy rains and massive water flow, the ponds, unable to withstand the pressure, collapsed causing massive landslides downstream.

Slope failure
According to World Resources Institute (WRI), India, most of the landslides in Kodagu occurred due to slope failure along the roads as observed in landslide-affected areas. Moreover, the landslides may have exacerbated due to inadequate landslide prevention measures like retaining walls and drainage channels.

“A slope failure is a phenomenon when a slope collapses abruptly due to weakened self-retainability of the earth under the influence of anthropogenic (realignment of slope/ blasting/ deforestation etc) as well as natural (extreme rainfall or earthquake) reasons. Most commonly slope failure happens due to a mix of anthropogenic and natural reasons which make a slope unstable, leading to mass movements,” says Samrat Basak, Director, Urban Water (WRI India).

Global Forest Watch says that Kodagu district suffered a loss of approximately 2,908 hectares (equivalent to more than 4,000 soccer fields) of tree cover between 2000 and 2017. Loss in forest cover can be attributed to either infrastructure development and construction of residential or commercial buildings, or the conversion of forest land to farming or plantation land. A map of affected areas also show that farming and plantation also contributed to certain landslides.

It is evident from the Kodagu calamities that these disasters are primarily caused by stressed water, land and biosphere system coupled with extreme climatic events.

What Kodagu needs right now is an exhaustive scientific study to understand causes for the landslides and find remedial measures to avoid such tragedies in the future.

(Image source: WRI India, contains modified Copernicus Sentinel data [2018]; Processed by Raj Bhagat P, Samrat Basak)

5 thoughts on “What caused landslides in Kodagu?

    1. Thank you Mr. Shree Padre for your encouraging words.

      According to Google, a slope failure is a phenomenon that a slope collapses abruptly due to weakened self-retainability of the earth under the influence of a rainfall or an earthquake.

      We will check with WRI for more details on slope failure and come back to you.

      Like

  1. Very good assumptions are made by many. Yet some detailed studies for scientific analysis are required. Felling trees alone cannot be the reason as coffee estates too, have the good number of shade trees and coffee plants to prevent instability of soil up to 1 -2 m. The July tremor has something to do with landslides due to the followed heavy downpour of 3 days in Aug. We will be happy if scientists of different Institutes take up and continue the studies till they get some good data to finalise the cause and to draw up an action plan. It will be a pioneering sort of work for scientists as such occurrences are rare and unique in nature.

    Liked by 1 person

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s