25 Jul 2019 | Cryosphere

Sediment management for sustainable hydropower development in Nepal

2 mins Read

On a fact-finding mission: Participants identify gaps and discuss solutions for sedimentation and hydropower development in Nepal. (Photo: Jitendra Bajracharya/ICIMOD)

Hydropower generation is a viable base upon which economies could flourish in the Hindu Kush Himalayan (HKH) region, but excessive sediment loads in rivers and reservoir sedimentation pose a major challenge in operationalizing and maintaining sustainable hydropower plants. “There is no doubt that sedimentation has to be the main agenda for sustainable development in the hydropower sector,” concurs Sailesh Chitrakar, Senior Researcher at Kathmandu University’s Turbine Testing Lab. “Sedimentation impacts production and shuts down turbines, resulting in higher costs through frequent maintenance and repair costs”.

The HKH region is vulnerable to climatic changes, which directly affect erosion, sediment transport, and deposition processes at a basin scale. Long-term data are needed to understand sediment dynamics and design sustainable hydropower projects. As the sediment-monitoring data currently available are inadequate for informed decision making, sedimentation continues to hinder development of economically viable hydropower infrastructure.

To fully understand the extent of challenges posed by sedimentation and devise a way to address them, the Norwegian Water Resources and Energy Directorate (NVE) and ICIMOD organized a fact-finding workshop on 22 May 2019. The workshop – attended by representatives of key organizations involved in hydropower development and sedimentation in Nepal – mapped out the status and challenges of sedimentation.

Key issues identified during the workshop

As the lack of and access to reliable and quality data is the major issue, the first step towards understanding the extent of sedimentation is to develop and establish a standardized data collection protocol. Hydropower companies and other infrastructure development organizations could particularly benefit from such a standardized data collection guideline and improved access to quality data.

“Sediment data and catchment management plans help identify potential project sites. Quality data can contribute to a comprehensive river basin plan,” shares Sabina Kharbuja, Senior Divisional Engineer, Water and Energy Commission Secretariat (WECS), Government of Nepal. Santosh Nepal, Water and Climate Specialist, ICIMOD, similarly sees the need to conduct and act on the basis of rigorous research: “More holistic research on land use/land cover change, erosion, and sedimentation is required to better understand the causes and effects of erosion and sedimentation at a basin scale. Better data and scientific analysis can help make informed decisions for hydropower planning and development”. Extensive research on the cause and patterns of erosion and sedimentation, including during extreme events, is also needed for sustainable hydropower plant development.

On the policy front, the workshop highlighted the need to include progressive licensing conditions, which could encourage private hydropower developers to invest in long-term watershed management. The existing laws require hydropower developers to hand over ownership to the state after 30 years.

The NVE and ICIMOD are collaborating for the second phase of the Snow Accumulation and Melt Processes (SnowAMP) project, which aims to improve knowledge on sediment dynamics for sustainable hydropower development in Nepal. The SnowAMP project is implemented with financial support from the Royal Norwegian Embassy, Kathmandu. The project plans to address several other issues around hydropower development in Nepal.