Poorly maintained sewers, the main culprit

Frequent caving-in of city roads:

Jarring experience for pedestrians, vehicles:

By Ranil Wijayapala

The sudden caving-in of main roads and byroads in the city of Colombo has become a frequent occurrence for the past three to four years with several craters providing jarring experiences for motorists as well as the public.

The huge pit which opened up in Darly Road, Maradana opposite the New Olympia Cinema, in October 5, 2005 was the start of the series of caving-ins on main roads. There was another one on Layard’s Road, Colombo 5, in November 2006 followed with one reported along Amarasekera Mawatha, Wellawatte.

Again in May 2007 with heavy downpour in the city, another gaping hole was recorded closer to Roxy Theatre, Wellawatta, causing a traffic jam along Galle Road. Another crater showed up in 2008 closer to Sumanadisi Hotel in Wellawatte, thus making craters headline news almost a regular feature.

The Roxy Theatre crater in Wellawatte remained unattended for nearly an year causing chaos in traffic along Galle Road.

President Mahinda Rajapaksa who presided at the Western Province Development meeting held in Panadura, drew the attention of the relevant authorities on this crater and ‘cracked the whip’ by calling for immediate action.

Although, repairing the crater appeared to be a simple job, the real story behind the sudden appearance of these huge holes smees to be a very complicated one, because the cause of it leads to the city sewerage which is over 100 years old and is in need of immediate rehabilitation.

Explaining the real situation, the Special Commissioner of the Colombo Municipal Council Omar Kamil said that crater on Galle Road near Roxy Cinema was due to the collapse of an existing sewer.

“It had happened earlier in different places. We had one at Chitra Lane, Narahenpita another at Layard’s Road at three locations in Wellawatte closer to one at Madampitiya and another at Mattakkuliya”, he pointed out.

According to Kamil the existing sewerage, serving the city ratepayers was laid over 100 years ago to serve 100,000 people and today, it serves to over one million population, on a single day.

“Therefore, the bursts appear to be quite natural, because they have reached bursting levels”, he added.

Providing an immediate solution to this problem appears to be a big task for the CMC as it calls for huge funds to repair or the existing sewerage.

The crater near Roxy Cinema

Work on the crater in progress

The CMC after holding discussions with the Government has drawn out a plan funded by the Asian Development Bank (See box story) to repair and rehabilitate the network.

“But to close up the craters the CMC has laid out a program to repair them immediately”, he added.

For the Wellawatte crater, the CMC has awarded the contract to the lowest tenderer, six months ago. The project is estimated to cost around Rs. 6.5 million.

“Unfortunately, the contractor has defaulted in bringing in the pipes needed. At the Western Provincial Council Development meeting held under the patronage of President Mahinda Rajapaksa at Panadura he had ordered immediate solution by cancelling the existing tender and reaward it to the next bidder”, he added.

We hope to do the repairs covering Galle Road stretch in a month. At least the main stretch will be completed in two weeks”, Kamil added.

The Commissioner also pointed out that these occur not only in the sewerage which were laid over 100 years ago during the British rule, but also in the lines that were laid in the 1980s, when it was brought under the National Water Supply and Drainage Board.

Explaining further, D. H. Gunasekera, Director Engineering (Water Supply and Drainage) of the CMC said the section of the sewerage that collapsed is not the one that was laid 100 years ago.

The sewerage was laid between 1906 and 1920. During that period there was a transfer of ownership of the sewerage in 1981 when there was gazette notification calling in all local authorities to hand over the water sector to the National Water Supply and Drainage Board.

The local authorities including the CMC handed over the water supply section to the Water Board and in return they given back the operations and maintenance part to be done by the Municipality which was done upto 2001. During the same period there was another gazette notification to hand over the sewerage section also to the same authority. Following that notification the National Water Supply and Drainage Board had come up with a project to lay 24 kilometre of sewers in the city with foreign funding. The project was directly under the Water Board who were in charge of supervisions and the accessories were provided by the Municipality.

“The sewers that are collapsing now is the one which was laid during that period but not the one which is over 100 years old”, he added.

“We are in the habit of doing ad-hoc repairs whenever there is a collapse which is not a permanent solution for the entire 24 km stretch of sewerage lines. We have to study it and have solution immediately with the available funds, he added.

He said that most vulnerable areas are located closer to the outfalls of the sewerage network. We have two outfalls, the Northern outfall in Mutwal and the Southern outfall at Wellawatte. For instance the Wellawatte outfall carries the sewage from Kollupitiya, Bambalapitiya, Borella and Kirulapone areas.

The one at Mutwal carries the sewage from Dematagoda, Maligawatta and Mattakkuliya area. In addition, the lines from Kotte, Dehiwala, Mount Lavinia and Kolonnawa are also connected to these outfalls.

“What we had detected was that the pipes are washed, not in the bottom sides but at the top. This is mainly due to poor quality”, he added.

The good old ones are made out of cement with bricks. The system has been working without proper rehabilitation due to lack of funds. When sewage flows along the lines there is sulphur formation which attacks the cement causing the decay.

“The collapse near new Olympia theatre was due to this, Gunasekera added.

According to field engineers, the bursts are also due to people diverting rain water into the sewer line after causing heavy pressure. Many craters appear when the city experiences heavy rainfall.

To repair these pipelines is very difficult task as they are 10 to 15 metres deep. The crater on Galle Road (Roxy Theatre) is one where the workers have to dig very deep to open the sewer lines.

Eng. Gunasekera said the CMC is planning to improve the existing sewerage through the ADB funded project, as an immediate solution for the problem.

According to him, the present sewerage in Colombo city caters to only 75 percent of the population in the city whereas there is another 30 percent living in Colombo East area without where there is no facility.

“There we don’t have our underground system to cater to their needs. They solely depend on site sources like the septic tanks. That area has also been earmarked by the Municipality under the ADB funded project and we have started laying 6 km of sewers in one section in the area”, he added.

There will be 10 percent increase in the sewerage pipe availability within the system once that section is added to the main network”, Gunasekera added.

He said the ADB funded project also includes two packages, one for the institutional development and the other for the design supervision of the sewerage lines package.

“All these years we were providing this service free of charge for the people in Colombo.

Our expenditure is very high for this service. Annually we spend about Rs. 500 million for maintenance. Earlier, the water was also provided to the people free, but with the establishment of the Water Board the water rates have been introduced. In future we may have to go for some arrangement to charge a fee for the use of sewerage lines”, he added.

“Presently we are alright, but with this new development and for covering the most critical areas of another 10 km of new sewers and rehabilitation of pumping station will make the system well developed”he added.

He said after the network is developed it could go on for another 25 to 30 years. But the responsibility is with the people in the city to make use of the system properly, without dumping unnecessary items into the sewerage system causing immense hardship to the general public.