While the country has been compelled to focus on a long-term mechanism to cope with the frequent climatic changes experienced in several parts of the country since lately, authorities have also pushed for a fresh study on the mountain slopes to ascertain the situation and the possibility of future landslide threats during and after extreme weather conditions.
The National Building Research Organisation (NBRO) submitted a proposal to the Treasury recently to conduct fresh inspection of terrains and slopes in the hill country that are frequently affected by landslides. The proposal comes after Sri Lanka faced one of its worst years in terms of climate changes in decades.
Over the years, a period of heavy rains is usually followed by landslide warnings to residents who live along the slopes that are likely to be affected. Despite these warnings, thousands of people have been continuously affected by landslides, losing their homes. According to NBRO in the past 25 years landslides affected the lives of over 150,000 families incurring an economic blow of around Rs.2.8 billion on relief measures.
Issues such as unplanned construction and de-forestation have further aggravated the situation. Frequent forest fires too had destroyed the trees thereby exposing the soil to direct rainfall. Experts point out that such issues cause the soil to loosen up and get eroded with surface runoff. According to NBRO landslide incidence exacerbate with excessive rainfall that weakens the stability of slopes.
Rapid population growth leading to increased urbanization, de-forestation and unplanned development, increases vulnerability in areas already prone to landslides. In recent times the threat of landslides which claimed hundreds of lives, destroyed properties, dealt a heavy blow to the economy and even damaged the natural environment showing an increasing trend.
The Disaster Management Centre (DMC) has identified and marked certain areas as vulnerable for landslides. According to the NBRO website, of the 65,000 sq kms of total land area, nearly 20,000 square kilometres has been identified as landslide prone areas. It is approximately 30 per cent of Sri Lanka’s total land area, encompassing 10 districts; Badulla, Nuwara Eliya, Kegalle, Ratnapura, Kandy, Matale, Kalutara, Matara, Galle and Hambantota. The warnings to the public are generally based on the areas that have been identified as landslide-prone areas.
In April this year, the government made it mandatory for all construction works along the slopes to be carried out with the approval of the NBRO. However, officials pointed out that a proper strategy needed to be formulated to address the situation which already exists.
Even though the authorities had an idea about the areas that were prone to landslides, they lacked a long-term strategy to tackle the problem.
Director General, NBRO, Dr. Asiri Karunawardena told Weekend Nation that the proposed inspection intends to look at the seriousness of the issue and also to ascertain whether there were any new regions that were prone to landslides.
“We have submitted a proposal to the Treasury in order to stabilize the situation. It is at a proposal level. The reason behind this is to figure out how we could avoid damages caused due to landslides,” he said.
Impact on transportation
Apart from causing damages to property, the issue has also heavily impacted transportation services. Karunawardena said that providing a safe transportation passage was one of the key aspects of the inspection process since there were landslides reported in non-residential areas as well which had blocked or damaged several sections of the railway lines.
“We cannot re-design the railway lines as they would prove to be costly,” he said. Karunawardena pointed out that they hoped to take measures including re-designing the drainage system. “There are several ways to mitigate this. We could build concrete structures, or try reinforcement measures such as soil nailing,” he said.
Accordingly, soil nailing is a technique reinforcing bars which are drilled into the unstable soil where the bars would prevent the soil from sliding downwards.
“We have already commenced using this technique in locations along the Southern Expressway,” he said.
“We are also looking at the possibilities of firming up the soil through re-forestation and vegetation. However, all these measures would vary from place to place. What works in one area would not work in another,” he added.
Dearth in experts
On the other hand, academics have pointed out that Sri Lanka at the moment had a dearth in academic experts who do research in the subject of landslides.
“There are experts qualified. But they cannot do a comprehensive research owing to the workload,” Senior Lecturer, Forestry and Environment at the Sri Jayawardenapura University, Dr. DT Jayawardena said.
“The University of Peradeniya has a department for this subject and there are a few experts doing research. There are many others who are involved in related subjects. But there are very few in terms of landslides,” he said.
(Pic by Chamila Karunaratne)