At the start of 2018 work began in Colombo, Sri Lanka, to construct a large pumping station designed to extract water from flood prone parts of the city.
Colombo sits on the Kelani River making it vulnerable to flooding as during heavy rainfall the hills and plans of west Colombo create rapid runoff that enters into the see and can spill into the canals across the city.
Colombo has a number of gates throughout the canal network built to stop floodwater emptying into the city. However, when the gates are closed there is no outlet for rainwater gathering in the city.
However, the city is hopeful a new pumping station will protect the community even when the gates are closed.
The station, on the south bank of the Kelani River, will remove rainwater that falls inside the city and pump it out to the river, on the other side of the closed floodgates.
The project costing $12 million is expected to be completed in 2019, along with another similar pump further up the river course.
There are also plans to build a third pumping station that would pour excess water into Beira Lake, a 65 hectare body of water in Colombo that has its own outlet to the sea.
Colombo has been encouraged to construct pumping stations since 1999; however, in recent years the city has experienced worse and more frequent flooding.
Flooding in the city has worsened notably in the last ten years; in 2016 and 2017 large areas of the city were flooded as the monsoon season began in May.
S.M. Premalal, the director general of the country’s Meterological Department commented:
“The problem is…the intensity and intervals of rain. We are now getting large amounts of rain in very short bursts,”
In May 2016, parts of Sri Lanka’s western plains received over 300mm of rain within two days.
The Metro Colombo Urban Development Project conducted a risk assessment last year that estimated the Colombo district suffers yearly damages of $45 million due to flood and heavy rain.
The pumping stations are part of a $320m to create an effective flood protection plan for the city, as well as improving roads and solid waste disposal.
Climate experts warn that cities like need to adapt to changing rainfall patterns. The pumping stations offer insight into the future of flood management in cities in light of climate change.
Image credit: Joe Qian