The 3S River Basin

The Sekong, Sesan and Sre Pok trans-boundary rivers of Cambodia, Lao PDR and Viet Nam are tributary rivers of the Lower Mekong, contributing up to 18 percent of its annual total discharge. The 3S Rivers – as they are collectively called – are instrumental in the hydrology of the Lower Mekong.

The 3S river basin is also a breadbasket for the livelihoods of over 3 million people, many of whom depend directly on the rivers’ resources. As the Asian region develops, the 3S Rivers are expected to continue playing a significant role in the economic growth of the basin, and the region as a whole.

BRIDGE Objectives in the Mekong Region

To promote a shared vision for sustainable use of water resources in the 3S river basin, IUCN is working towards achieving the following objectives:

Establishing frameworks for institutional arrangements and trans-boundary collaborations
As a preliminary approach to building a comprehensive governance road map for the 3S basin, a bilateral river basin committee will be established in the Sekong river basin. Appropriate country-driven frameworks for institutional arrangements will be developed in the Sesan and Sre Pok basins.

Enriching and fortifying knowledge sharing platforms
Situational analyses performed to fill in knowledge gaps, as well as secondary information on the 3S river basin, will be consolidated and hosted within an accessible online database. Stakeholders can use this database as a knowledge resource hub.

Enhancing leadership and governance capacities
Training programmes on water resources management concepts, such as environmental flows and hydro-diplomacy will be offered to local leadership to encourage integrated water resources management and policy advocacy engagement.

Quick Facts about the 3S Basin
  • Catchment area: 78,650 square km

  • 33% of the total basin area lies in Cambodia, 29% in Lao PDR, and 38% in Viet Nam

  • The largest tributary of the Mekong

  • 3S rivers flow from different points in the central highlands of Viet Nam. They merge in Stung Treng, Cambodia.

  • Map of the 3S Basin
    • Map of the 3S Basin

      Map of the 3S Basin

      Photo: (c) Mekong River Commission