- CMC begins clean-up after flash floods
- Authorities warn of more heavy rain
The Ministry of Transport, Highways and Urban Development is working towards establishing a drainage system capable of withstanding rainfall of up to 120 millimetres (mm), Clean Sri Lanka Task Force Convenor and Secretary, Senior Additional Secretary to the President Russel Aponsu said.
Speaking to The Daily Morning yesterday (8), he said flash floods could occur again in Colombo due to weather conditions triggered by El Niño, and that measures would be taken to mitigate their impact.
Meanwhile, the Colombo Municipal Council (CMC), in collaboration with the Sri Lanka Land Development Corporation (SLLDC) and the Urban Development Authority (UDA), yesterday (8) launched a drainage cleaning operation in several parts of Colombo under the supervision of Colombo Mayor Cally Balthazaar, following the flash floods that hit the city on 6 November.
The operation aims to restore the proper flow of rainwater through the city's drainage system, mitigate the impact of expected rainfall of around 100 mm in the Colombo District in the coming days and serve as the first step towards a long-term plan to address drainage-related issues in the district.
The cleaning operations covered areas including Colombo North, Kirulapana Canal, Mateland Place, Bloemendhal, Dematagoda Serpentine Canal, Norris Canal and Narahenpita.
Garbage obstructing drainage systems was removed, while canals that had been filled with soil and other material were also cleared. The collected waste is being transported to a yard maintained by the SLLDC.
The CMC is also planning to upgrade the existing drainage system, which was designed to withstand rainfall of up to 30 mm, to accommodate rainfall of up to 120 mm.
Speaking to The Daily Morning yesterday (8), Colombo Deputy Mayor Hemantha Perera said the cleaning operations would improve the city's ability to withstand further flash floods, as most of the previously blocked drainage systems had now been cleared.
"We believe that with the clearance of this garbage in the drainage system, better water drainage will happen and the consequences of any possible flash flood would not be as dire as the recent one," he said.
He noted that Colombo's drainage infrastructure had historically been designed to withstand rainfall of 30 mm within an hour. However, the city had received up to 130 mm of rainfall within one hour and 40 minutes, making it one of the highest amounts recorded since 2010.
Perera said the garbage collected from the drainage systems would be transported to a location under the Pahath Bim Sanwardhana Mandalaya. He added that the CMC's next responsibility would be to maintain the drainage systems following the cleaning campaigns.
Meanwhile, a group of appointed engineers is working on plans to identify where existing trenches need to be widened and where new trenches should be constructed.
Aponsu also said unauthorised constructions in certain areas had contributed to the intensification of flash floods. However, he said alternative accommodation would have to be provided to those living in such constructions before they could be removed.
The National Water Supply and Drainage Board also said its teams were prepared to respond to requirements arising from the widening of trenches and any damage to pipelines.
The exceptionally heavy rainfall of around 129 mm within one hour caused flash floods in Colombo on 6 November, inundating several areas and buildings, including the National Hospital of Colombo, in less than two hours.
The incident occurred against the backdrop of Prime Minister Dr Harini Amarasuriya having notified the CMC three weeks earlier of the need to clean canals and drainage systems.
Meanwhile, with the aim of finding a long-term solution to the risk of flooding in Colombo City, even during light rainfall, the CMC has drafted a comprehensive plan to minimise flood risks and build resilience among local residents, Deputy Colombo Municipal Commissioner Eng. A.D.S. Rohana told The Daily Morning yesterday.