The Mekong River Basin is undergoing rapid hydropower development. While this offers substantial economic benefits and energy security to the region, it raises significant environmental and social concerns, necessitating coordinated management and cooperation for sustainable development.

Hydropower development in the Mekong Basin is driven by both upper and lower basin countries. China leads in the Upper Mekong, known as the Lancang, with 12 operational mainstream dams including Tuoba. Meanwhile, the Lower Mekong Basin (LMB) is witnessing an acceleration in hydropower development across several countries, with Lao PDR at the center of this activity. Lao PDR holds the largest share of hydropower projects in the LMB, with 98 projects accounting for 64% of the region’s total installed capacity. The country’s hydropower infrastructure is a vital component of its economy, serving both domestic energy needs and export commitments to neighboring countries.

Across the LMB, 88 hydropower projects are operational, with an installed capacity exceeding 13,257 MW. An additional 20 projects are under construction, and 14 are in the planning phase. If all these projects are completed, the region’s total hydropower capacity could more than double, reaching 27,302 MW.

The expansion of hydropower in the Mekong Basin offers several key benefits:

• Energy Security: Hydropower provides a reliable source of renewable energy, critical for meeting the region’s growing electricity demands.
• Economic Growth: Hydropower projects generate significant economic opportunities, including job creation during construction and ongoing operation.
• Improved Infrastructure: Rural communities benefit from improved access to electricity, enhancing quality of life and economic productivity.
• Revenue Generation: The sale of electricity, particularly to neighboring countries, provides an important revenue stream, contributing to national development.
• Flood and Drought Mitigation: Regulated water releases from reservoirs can help manage flood risks and ensure water availability during dry periods.

However, the rapid development of hydropower in the region also presents serious challenges:

• Altered Flow Regimes: Dams disrupt natural river flows, affecting downstream ecosystems. Changes in water levels, sediment transport, and water quality can have cascading impacts on biodiversity, particularly fish populations and other aquatic life.
• Loss of Wetlands and Forests: Dam construction and the creation of reservoirs can inundate large areas of land, leading to the loss of valuable ecosystems, including wetlands and forests.
• Reduced Sediment Flow: Dams trap sediment that would otherwise flow downstream, a crucial process for maintaining the fertility of the Mekong Delta and supporting agriculture and fisheries.
• Displacement of Communities: Reservoir creation often forces communities to relocate, disrupting livelihoods, especially for those dependent on fishing and agriculture.
• Impact on Fisheries: The disruption of fish migration patterns due to altered river ecosystems threatens the food security and income of millions of people in the basin.

The transboundary nature of the Mekong River further complicates hydropower development. Water resource development in one country, particularly in the upper reaches of the basin, can significantly impact downstream nations. This dynamic highlights the critical need for cooperation, joint planning, and effective governance among all Mekong countries.

To mitigate the risks while harnessing the benefits of hydropower, stakeholders across the region, including the Mekong River Commission (MRC), are promoting sustainable hydropower development through the following approaches:

• Basin-wide strategies such as the Basin Development Strategy and the Sustainable Hydropower Development Strategy, which aim to optimize national plans while minimizing regional costs.
• MRC Procedures including Notification and Prior Consultation, which provide independent reviews of individual projects and facilitate information sharing and consultations with member states and the public.
• Technical guidelines such as the Preliminary Design Guidance for mainstream dams, designed to avoid, minimize, and mitigate adverse project impacts.
• Studies and assessments that support informed planning and decision-making.
• Monitoring regimes that track impacts, enabling adaptive management and ensuring public access to information.

In the hydropower sector, the MRC is tasked to help ensure that increasing demand for electric energy in the Member Countries is met without causing detrimental effects on the environment or local communities – an aim which requires a hydropower strategy that is based on best practices.

The first Hydropower Development Strategy (HDS) was formulated in 2001 in recognition of the MRC’s role as a river basin organisation for regional co-operation on sustainable hydropower development, utilisation, and management in the Mekong River Basin. Through the HDS, a variety of studies, guidelines, and tools were developed to provide guidance for the MRC’s involvement in hydropower development activities. 

In 2008, the Initiative on Sustainable Hydropower (ISH) was established to advance regional cooperation and assist the Member Countries in relating decisions on hydropower management and development to basin-wide Integrated Water Resources Management (IWRM) perspectives. The Initiative developed knowledge platforms and networks enabling the Member Countries to routinely exchange information, share experiences, and collaborate on tools and practices in sustainable hydropower (see below).

The MRC Strategic Plan (SP) 2016-2020 underlined the rising sense of urgency among stakeholders for the need to move basin development towards more optimal and sustainable outcomes that could address long-term needs, including environmental protection as well as ensuring water, food and energy security. In order to achieve these goals, the Member Countries agreed to update the HDS 2001 by taking into account major changes in the basin that had occurred over the last 18 years. The update strategy, now called the Sustainable Hydropower Development Strategy (SHDS), also identifies opportunities to enhance benefits beyond national borders and minimise adverse transboundary impacts. The SHDS, expected to be finalised in 2021. An agreed set of strategic priorities and actions will be implemented to ensure delivery of the SHDS objectives.

In addition, the updated Preliminary Design Guidance (PDG) for Proposed Mainstream Dams in the LMB (2009) is being finalised to provide design guidance in the form of performance targets, design, and operating principles for impact mitigation measures in key areas reflecting the current hydropower development situation and international good practice. The updated PDG formed the basis for the development of guidelines for hydropower environmental impact mitigation and risk management in the lower Mekong mainstream and tributaries.

Since there is potential for further development of hydropower in the Mekong Basin, the Basin Development Strategy (BDS) 2021-2030 and MRC SP 2021-2025, promotes the concentration of hydropower development in storage-backed cascades to: (i) increase dry season flows and power generation, (ii) provide reliable flows to downstream run-of-river hydropower facilities and improve their performance, (iii) reduce downstream flood and drought risks and enhance dry season navigation, and (iv) create opportunities to forego hydropower development in still undeveloped watersheds with high ecological value.

In relation to measures to mitigate the adverse impacts from water resources development, the MRC will continue to work with countries to integrate the various regional products developed over recent years into national systems. For instance, the Transboundary Environmental Impact Assessment (TbEIA) guidelines into national policy and regulations, and the updated PDG into the planning and management of hydropower.