Living with landslides: Community-based programme teaches combat techniques

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As landslide deaths become increasingly regular in Sri Lanka during heavy rains, a community-based science programme offers a life-saving mechanism. Getting to know about an imminent landslide even a second earlier could make a big difference, but often the early signs are ignored. To address this issue, an ambitious programme was launched last year.

Nature often gives early landslide warnings such as changes in the landscape, cracks on walls and difficulty in closing or opening doors or windows. (read the box story).  Drawing people’s attention to such early warnings is one of the aims of the Community-Based Landslide Early Warning Project (CBLEW). It teaches people in a landslide-prone community to monitor early signs and prepare an initial response.

A house in Biyagama affected by a landslide. Pic by Lal S. Kumara

The National Building Research Organization (NBRO), the premier institution responsible for dealing with landslide prevention, has identified several risk zones.

NBRO Geologist Darshani Rajapakse said the CBLEW project had been introduced to about 100 villages in Badulla, Nuwara Eliya and Kegalle.
The first step of the programme is to educate the communities on early signs of a landslide and how to respond when disaster occurs. The villages are then taught how to use simple equipment such as a rain gauge, a basic but useful device that can save lives.

According to scientists, 75mm rain for 24 hours in a landslide-prone area should put the people on ‘alert’ while 100mm rain upgrades the risk level to a ‘Warning’. A rainfall of 150mm for 24 hours means it is time for ‘evacuation’ for safety.

The third stage of the programme trains the villagers to map the danger zone, identify safe areas to run in case of a disaster and plan safe passage for evacuation. The last stage of the project involves the setting up of a monitoring committee consisting of active participants chosen from the community.

Ms. Rajapakse said the communities were also taught how to use extensometers which monitor earth movements. She said the NBRO had plans to set up automated extensometers in risk areas where cracks had been sighted. If any major movement of the earth is detected, relevant people are notified through a text message.

According to NBRO studies, 20 percent of Sri Lanka’s land or 13,000 square km in 13 districts is landslide prone, with the Badulla, Nuwara Eliya, Matale, Kandy, Kegalle, Ratnapura and Kalutara districts being the top seven districts on the danger list. Areas with isolated mountains and earth mounds in the Monaragala, Kurunegala, Gampaha, Galle, Matara and Hambanthota districs have also been identified as danger zones. The NBRO said it wanted to implement the CBLEW project in all the areas identified as danger zones.

Published on 28.05.2017 on SundayTimes http://www.sundaytimes.lk/170528/news/living-with-landslides-community-based-programme-teaches-combat-techniques-242728.html

Early warnings of a landslide

  • Changes occur in your landscape such as patterns of storm-water drainage on slopes (especially the places where runoff water converges), land movements, small slides, flows, or progressively leaning trees.
  • Doors or windows stick or jam for the first time.
  • New cracks appear in plaster, tile, brick, or foundations.
  • Outside walls, walks, or stairs begin pulling away from the building.
  • Slowly developing, widening cracks appear on the ground or on paved areas such as streets or driveways.
  • Underground utility lines break.
  • Bulging ground appears at the base of a slope.
  • Water breaks through the ground surface in new locations.
  • Fences, retaining walls, utility poles, or trees tilt or move.
  • A faint rumbling sound that increases in volume is noticeable as the landslide nears.
  • The ground slopes downward in one direction and may begin shifting in that direction under your feet.
  • Unusual sounds, such as trees cracking or boulders knocking together, might indicate moving debris
  • Collapsed pavement, mud, fallen rocks, and other indications of possible debris flow can be seen when driving (embankments along roadsides are particularly susceptible to landslides).

Source: http://www.weather.com

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