On a precarious footing

Six districts identified as being vulnerable to landslides:

by Dhaneshi Yatawara

Two landslides within six months in Haldummulla in the Badulla District were warning signals. Six more districts were identified last week as being highly vulnerable to landslides.

Asst. Director Udaya Kumara explaining how to use a rain gauge

A landslide prone area in Haldummulla

Disaster Management experts have entertained fear that the central mountainous area of the country is in great danger. Unplanned human activities have been blamed for disturbing the natural ground set up. Disaster Management officials said people living in these areas not being aware of the grave situation face the greatest threat.

People living in estates, slopes and mountains in the Badulla District seem to be facing an uncertain situation. "Unfortunately despite the pre-warning systems in high risk areas and instructions on evacuation methods, people tend to forget them in few weeks," said Udaya Kumara, Asst. Director of the Badulla district Disaster Management Centre (DMC).

The DMC and the National Building Research Organisation (NBRO) established automated rain gauges established as an early warning system in seven high risk areas in the Badulla District.

"The system is created to transmit the information automatically to DMC and the NBRO offices in Colombo," said Udaya Kumara.

In addition, rain gauge tables have been provided to each Grama Niladhari Division for the villagers to be alert on the weather pattern changes. According to Udaya Kumara people have been instructed to be alert after the rainfall reaches 150mm within 24 hours following continuous heavy rain. Parallel to the rainfall measurement several other environment signs such as earthslips and trees falling need to be taken notice of.

Evacuation plan

"Villagers are told and trained to follow the evacuation plan but the problem is people do not keep this in mind - they forget," said Udaya Kumara.

Evacuation plans are set up in villages and villagers are trained from time to time. The responsible team of the village consists of Disaster Management Committee and a Civil Defence force. "Periodically we have carried out drills to inform people of the evacuation plan. Yet when the real disaster strikes they do not follow it. At times, the land is about to slide and villagers refuse to move," said Udaya Kumara and added that this attitude needs to change.

Families have been moved away from the recent landslide - hit area in the Nikapotha Grama Niladhari Division in Haldummulla. They are now living with their relatives in other areas in Badulla. The abandoned rubber plantation devastated by the landslide has no human activities any more. There are resettlement problems in Miriyabedda due to the lack of safe lands to be given to the people.

When the National Building Research Organisation started mapping out Badulla district, certain areas did not show any human activities. Therefore, they were not given priority.

High risk areas

"The problem started when people commenced work that altered the natural setting in these high risk areas, said Head of NBRO's Landslide Research and Risk Management Division, R.M.S. Bandara. Unplanned and unauthorised human activities in high risk areas have been identified as the main cause for frequent landslides. Lack of human resources in disaster management is another problem. A small number of of people tackling a growing issue of disasters in a district is becoming unmanageable now.

Dr. Pathmakumara Jayasinghe, a geologist of the Coordinating Secretariat for Science, Technology and Innovation (COSTI) said that numerous cracks have been identified on the ground in Haldummulla making it a landslide-prone area," said Dr. Jayasinghe.

"These underground cracks are in different directions and filled with water which we call, aquifers. When there are disturbances to aquifers like making tunnels to extract water, a hole can be created in the ground when the water drains through these tunnels.

The natural stability of the ground collapses. This can happen when people dig the ground to make tube wells and dug wells," he said.

In addition to the cracked underground the Badulla and Haldummulla is well known for its metamorphic rocks which is geologically known as marble. Underground rocks alter the mineralogy, texture and chemical composition when exposed to extreme temperature and chemical changes create these metamorphic rocks.

With the passage of time there are cavities in these rocks to be filled with water and due to human activities if the water drains from the cavities, the ground gives way creating a huge hole.

"But to understand the real ground conditions, there should be a specific geological study. It will help find the exact reason for these frequent landslides," added Dr. Pathmakumara.

And it is high time to find out whether the central mountains, the water catchment areas of the country are in danger.