The wetlands of Colombo – described by one expert as "the lungs and kidneys" of Sri Lanka's capital, but long since neglected and polluted – are being restored, which is helping to manage floods and boost biodiversity.
Once "used as trash dumps", the wetlands have been "remade as flood-buffering parks", said the Bulletin of the Atomic Scientists. Sri Lanka's ancient kingdoms "thrived in a well-managed wetland system" where the marshes were used for transport and to grow food, said the BBC.
But in the British colonial period from the late 18th century, the wetlands were drained to build housing and businesses. It was only after a series of calamitous floods in 2010, which affected nearly 700,000 people and submerged the country's parliament, that government policy began to shift.
Colombo is located in a river basin, so the city is "naturally prone to floods", but wetlands "act as a flood buffer", with 40% of floodwater draining into wetland areas. This is not their only benefit: they also "sink carbon, purify the air and control temperatures".
The city now has four wetland parks and a number of other recreational spaces linked by wetlands. So although the city's history is a "cautionary tale" of what can happen when authorities are "prioritising urban growth" over "life-saving natural resources", the wetlands "could soon become the area's greatest strength".
If Colombo can "harness" its nearly 5,000 acres of wetlands to "limit destruction wrought by floods", its victory would "provide valuable lessons for cities around the world". | 
