Colombo Wetland Management Strategy — Ramsar Wetland City Flood Buffer

The Colombo Metropolitan Region's wetlands have shrunk by roughly 60% since the 1980s, from about 47.5 km² to around 19 km², under pressure from waste dumping, untreated wastewater and landfilling. That loss raises flood risk for the region's 2.3 million residents, 60% of whom directly depend on wetland-linked livelihoods such as fishing and rice cultivation.

In 2016 Sri Lanka's government adopted the Colombo Wetland Management Strategy, building on a 2015 Colombo Wetland Complex study, to fold wetlands into urban planning, halt further loss and restore degraded areas. Flagship sites include the Beddagana and Diyasaru wetland parks in Sri Jayewardenepura Kotte, converted from a former wildlife sanctuary and opened as public wetland parks in 2016 for passive flood control, cooling and conservation education.

The analysis behind the strategy found the wetland complex absorbs roughly 40% of the city's floodwater, and that at least 90% of the remaining 1,900-hectare complex must be preserved to hold the region's average annual flood loss under 1% of national GDP. Surveys record over 250 plant and 280 animal species across the complex, including nationally threatened flora and fauna, and in October 2018 Colombo became the world's first capital city recognised as a Ramsar Wetland City, one of only 18 cities selected globally in that inaugural round.

Even so, the wetlands continue to shrink by an estimated 1.2% a year, showing that the strategy has slowed but not stopped encroachment, and that continued political commitment is needed to hold the gains made since 2016.