The WATER project, coordinated by WWF, STEO and WWT and funded by the European Commission, promotes wetland technology as a sustainable solution for water purification for Vientiane, Laos, bringing additional benefits for flood control, biodiversity and for the people reliant on marsh products. 

The That Luang Marsh, sited on the eastern edge of Vientiane, has traditionally provided vital services for the city through flood prevention, wastewater treatment and livelihood support which have been valued at US$5million (approximately £3.25million) annually. Threats from unregulated urban expansion, increases in discharges from industry and untreated domestic wastewater are reducing the capacity of the marsh to provide these services.

The project demonstrated that an integrated wastewater management approach may be the most appropriate. The approach involved the production of designs for large-scale treatment wetlands within the marsh to treat wastewater from a catchment of 250,000 people; maintenance of the marsh for flood storage, water purification, biodiversity and food production through the production of an adaptive wetland management plan; and the construction of smaller scale wetlands designed to target industrial and domestic wastewater at source before it enters the city's network of ditches and canals leading to the marsh.