Landslides man-made

Cause: Haphazard steepening of slopes for constructions :

NBRO to issue new guidelines:

Rasika Somarathna

The National Building Research Organization (NBRO) investigations on recent landslides have revealed that 90 percent of the reported cases have been activated due to man-made causes. Haphazard steepening of slopes for housing and other construction have been identified as the cause for a majority of the slides.

Based on the findings, the NBRO is set to issue new guidelines for development, construction and human settlement activities in landslide prone areas. The NBRO is preparing landslide hazard zonation maps in 10 districts identified as having landslide prone areas.

The NBRO plans to provide maps detailing identified landslide prone areas and guidelines on constructions in those areas to local decision makers. The idea is to effectively incorporate landslide disaster risk reduction into local planning, Landslide and Services Division Studies head RMS Bandara said.

Ten districts have been identified by the NBRO as landslide prone areas. They are Badulla, Nuwara Eliya, Ratnapura, Kegalle, Kandy, Matale, Matara, Galle, Hambantota and Kalutara. Over 12,500 Kms of landslide prone areas are spread over these 10 districts.

According to Bandara the NBRO has completed landslide hazard maps in seven districts. The remaining three - Matara, Galle and Hambatota are to be completed before the end of the year.

According to an NBRO report following torrential rains in November and December 2010, and January 2011 which caused a number of slope failures resulting in loss of lives and property, 10 teams of scientists had been sent to investigate the 675 reported cases in six districts.

Studies on about half the cases have been completed. And among them the NBRO has identified about 256 houses that are at high risk and about 108 houses are at medium risk. Stretches of Walapane-Padiyapelella road, Kandy – Badulla road, Walapane – Nildandahinna road, and Haputale – Bandarawela road have also been identified as risky.

During recent rains several houses close to a quarry near Kandy town collapsed due to a landslide killing eight people and injuring several others.

The locations of both the houses and the quarry have been questioned.

The NBRO says that they investigated some of the failed sites before hand and had recommended measures to be taken to prevent future slope failures. Failure to implement the recommended measures was another cause for certain slides, they added.

They say that the importance of studying the geological and hydrological conditions of the selected sites and implementing suitable landslide mitigation measures prior to planning and constructing of any building is highlighted again with the occurrences of recent slope instabilities.

They point out that it is time to implement the precautionery measures which have already been formulated.