By measuring the “environmental flows” in rivers, WANI showed stakeholders alternate ways of allocating water among users while protecting downstream ecosystems and the services they provide. When WANI coordinated a rapid environmental flows assessment in the Huong River Basin, it brought together public officials, engineers and scientists in an action research project, which set off a process of learning and scaling up to the national and regional levels.


Central Vietnam’s Huong River is in the tropical monsoon region with frequent flooding in the rainy season, and low river flows and seawater intrusion in the dry season. Much of the river’s development has focused on construction of flood protection dams and a salinity barrage to prevent saltwater from penetrating inland.

An assessment of the river’s flow patterns led local, provincial and national authorities, along with local nongovernmental organizations, to incorporate the concept of “environmental flows” into planning and management of river basin development throughout Vietnam. River management using the concept of environmental flows requires allocating enough water to maintain the health of the river when water uses are prioritized. 

First, the government of Thua Thien Hue province adopted the environmental flows concept in managing the Huong Basin and its Tam Giang-Cau Hai lagoon. WANI supported Thua Thien Hue in identifying reforms needed to create the Huong River Basin Organisation.  Then, at the national level, the Department of Water Resources Management and Ministry of Natural Resources and Environment included the idea of environmental flows in the 'Towards the Year 2020' national water resources strategy, published in 2006.  Since then, the government has applied the concept of environmental flows in other river basins.

Demonstrations of environmental flows management in Vietnam and Thailand were the basis for region-wide awareness raising and capacity building. The WANI toolkit FLOW  was translated into six local languages: Vietnamese, Chinese, Thai, Khmer, Lao and Burmese. Translations were led by inter-disciplinary working groups, ensuring translation of the concepts rather than just the words, and successfully building national ownership of the concept and a constituency advocating its application in each country.

The rapid environmental flow assessment completed in the Huong Basin, provoked broad interest in environmental flows and created a solid platform for replication and scaling-up at national and regional levels. Currently, these concepts are being updated through the development of an Asian environmental flows network. This will focus on re-engaging with existing and new knowledge, and building a greater understanding on environmental flows amongst key regional stakeholders. 



Stories: Huong River Basin and Environmental Flows in Vietnam

Final Report: Rapid Environmental Flow Assessment for Huong River Basin, Central Vietnam (2004)

Basin Planning and Management ADB