Cause of the collapse: What experts and survivors say
As geologists and structural experts grapple with the question of what caused Metthotamulla's deadly garbage landslide on National New Year Day, survivors insist that it was a chemical sprayed by the Colombo municipality that triggered the tragedy in which more than 32 people perished.
With experts still conducting investigations and poring over the data they have collected, an official report which was due on Friday has been further delayed.
Although warnings were issued that the over 90 metre high garbage dump could collapse under its own weight, many residents said the disaster was precipitated by a chemical sprayed by Colombo Municipal authorities days before the tragedy.
They said they saw a Fire Brigade bowser spraying a chemical on the surface of the heap. When they asked why it was being done, they were told it was to ward off the stench.
Municipal Commissioner V.K. Anura confirmed that the CMC sprayed a chemical at the garbage dump to keep the smell off, but said it was not the first time they sprayed the chemical. "The spraying is done regularly," he said.
He refused to divulge the name of the deodorizer used, but said scientists had examined the chemical and found it to be harmless. Rejecting the residents' claim that it was the chemical that caused the catastrophe, the commissioner said he believed that the garbage dump collapsed because of the heavy rain that the area experienced a few days before the tragedy.
Colombo's Fire Brigade Chief P.N.R. Fernando said a 6,000-litre capacity bowser was sent to the site along with two firemen and the driver, but they returned after two hours.
Construction Ministry consultant C.H. Thalpe Gamage, who once served as the director of the Institute for Construction Training and Development (ICTAD), said a soil mountain could not remain stable beyond a height of 25 metres. The precariousness is more in the case of a garbage mountain as there is not enough cohesion and friction within. In addition, there is accumulation of bio-gas (methane) in pockets and even the heat produced by a slight friction can ignite a fire.
Other experts said that when land fills reached a certain height, the surface should be covered with suitable cover material and gas collection wells should be installed on the capped landfill. Perforated pipes have to be inserted vertically to tap the gas being produced below and it can be used as a source of energy.
Prof. Kapila Dahanayake, the Peradeniya University's Sedimentologist, said he visited the Meethotamulla site and he believed local conditions at the site contributed to the collapse. The dump, he said, was situated on marshy land with a canal running by its side. "The foundation was shaky," he said.
According to him, increased moisture and the heat generated from within probably led to the garbage landslide. The hot temperature outside could also be an added contributor, he said.
The geologist noted that the garbage dump had sloped upto the bank of the canal, allowing the water to seep through the garbage.
Prof. Dahanayake said the authorities should carry out a thorough study of the area before they set up a garbage dump. Geologists and other experts should be consulted before dump yards were identified, he said.
The emeritus professor said if decisions were taken based on proper geomorphic studies, people living near likely garbage sites need not fear of tragedies like Meethotamulla recurring.
Meethotamulla residents who accepted the Government's offer of new houses expressed mixed feelings about their decision. Many said that, while they did not like to live in flats, they were compelled to accept them, as the disaster had deprived them of their own homes.
Liyanage Niroshika said she was happy to receive a house from the Govt. She, however, stressed that, though she received a house and Rs.250,000 to buy furniture, it does not compensate for the two-story house she lost.
“I am happy to be with the other 30 families who were our neighbours yet, life in a flat is a new experience. Therefore, it’s hard to believe that I would adjust to the new house. This house is all we have now. If the Govt, took this action earlier, many lives would have been saved,” she said.
Another resident, Nilanthi Rajika, said she was happy with the Government's quick response to provide houses
"I was able to get house No.12 on the 9th floor. Though I accepted a house, many people are still refusing these houses saying, the quality of life is lesser in a flat. Some of the middle class people also don’t want to move into flats or displaced camps, due to their social status,” she said.
Mihijaya Wibushitha said, though they received houses, he could not be satisfied due to the fact that, he would never get a house with a garden.
He said that, earlier, his feet touched the soil and was able to, at least, plant a tree or keep pets, all of which has been lost after moving into the flat.