Development of a water management system for the Sesan-Srepok river basins

The Sesan-Srepok (2S) river basins are large transboundary tributaries of the Mekong River shared by Vietnam and Cambodia. In addition to the regulations on water use as stipulated in the 1995 Mekong Agreement, Vietnam and Cambodia’s cooperation in the management of river basins have also become imperative to better manage water resources and ensure sustainable development. A decision support system (DSS) ensures that both countries have access to updated information to improve short-term flood response and long-term water management for the river basins.

Challenge

In Vietnam, the upper 2S rivers are highly managed river systems for hydropower production. These hydropower developments have significantly modified the natural hydrological regime of both river systems. Operation rules for hydropower reservoirs in the 2S rivers were put in place earlier to ensure that the flows released at the Vietnam-Cambodia border could be as stable as possible. However, an advanced tool for improved decision-making was still lacking.

Vietnam’s Ministry of Natural Resources and Environment (MONRE) and Viet Nam National Mekong Committee (VNMC) decided to develop an advanced DSS – an easy-to-use, shared and centralised system for real-time flood management and water resources planning while abiding by legal requirements.

Solution

MONRE and VNMC initiated the development of a DSS to support river basin management, helping with water resources planning, flood forecasting and reservoir operations in the 2S basins. VNMC contracted two consulting firms for the development of the DSS and DHI was commissioned to supervise the implementation of these contracts.

The DHI team simulated more than 1000 km of rivers and included numerous reservoirs and their complex operations. This river model runs in real-time and provides accurate flood forecasts twice a day. Another model supports the river basin planning and management based on integrated water resources management (IWRM) principles, providing insight months in advance for the 50,000 km² catchment. MIKE OPERATIONS was chosen as the central part of this complex system, managing models in real-time while connecting to a variety of data sources and using a knowledge base developed for this project. A key aspect of this system is its versatility, as it can be easily extended at a later stage to meet future needs.

Water experts are working with the system through a user-friendly web-based interface that was designed to integrate naturally with VNMC workflows and processes. This provides the right level of insight regarding the river flow, flood risk and hydropower dam operation. This crucial for both countries to have a common understanding of the river flow (in normal and emergency cases) and to plan water releases from hydropower dams in Sesan and Srepok rivers crossing the border well ahead of time.

Results

The effective management of transboundary rivers is only possible when legal, environmental and economic factors are taken into account. The solution helps authorities consider all these factors, resulting in more effective transboundary river cooperation and safer communities.

• Transparent and science-based decision-making for better transboundary cooperation
• Flood forecasting and warning, including a reservoir operations model, for safer communities
• Versatile river basin management system for optimised long-term water usage