That Luang Marsh — Vientiane's flood-buffering urban wetland under development pressure

Vientiane sits in a shallow basin; the That Luang Marsh and neighbouring wetlands (roughly 2,000 hectares combined) intercept stormwater and wastewater from the city before it reaches the Mekong, acting as the capital's main natural flood buffer while also supporting fishing, rice and vegetable-growing livelihoods for surrounding communities.
A wetland ecosystem valuation cited in a UN Convention on Biological Diversity/TEEB case study put the marsh's annual economic value at just under US$5 million, with direct-use benefits such as fish and water spinach accounting for around 40% of that total. A 2023 peer-reviewed hydrology study in the journal Water (MDPI) measured the marsh removing on the order of 117±13 megagrams of nitrogen and 3.9±0.8 megagrams of phosphorus per year from water passing through it, and linked encroaching urban land use in the catchment to declining purification capacity.
The marsh is also a cautionary case: a 365-hectare stretch of it was carved out and designated the That Luang Lake Special Economic Zone for real-estate development, and UN reporting on Laos has framed the site as 'the paradox of urban development' — the wetland's documented flood-control and livelihood value has not stopped incremental infill and land conversion.

Read the full analysis: http://www.la.one.un.org/media-center/news-and-features/368-wetlands-and-the-paradox-of-urban-development