Countries in the Hindu Kush Himalayan region have been endowed with immense hydropower generation potential, but the changing climate and consequent changes in the hydrological regime pose grave questions regarding the future of sustainable hydropower development. The dearth of hydrological data, among other things, is a major impediment to harnessing the full potential of available resources in the region. Nepal, for instance, has a total hydropower potential of about 83 GW, of which about 43 GW is deemed technically and economically feasible. But without adequate hydrological data to support national strategies, its total installed capacity is around 1.1 GW, according to Economic Survey 2018–2019, released by the Ministry of Finance, Government of Nepal.

The survey also states that upon the completion of several ongoing hydropower projects, this capacity will be doubled by 2021. This is an uphill task, given the inadequate long-term data available on river flow during lean and wet seasons, precipitations patterns, and snow and glacier melt at the source. And with the hydrological variables changing rapidly owing to climate change, policy makers have the challenging task of accurately gauging the sustainability of Nepal’s hydropower plants.

Experts in the field have already identified the lack of data and standardized data collection guidelines as major problems in the current hydropower development industry. In a bid to address these data gaps, a group of hydropower experts including developers, government agencies, and researchers met on 5 June 2019 for a consultation workshop organized by ICIMOD and the Norwegian Water Resources and Energy Directorate (NVE) under the second phase of the Snow Accumulation and Melt Process (SnowAMP) project. The group agreed that a coordinated effort is required to make hydrological data available to stakeholders and suggested the following interventions:

• Create a standardized data collection guideline to ensure the consistency of data collected by hydropower developers. The current practice of every developer using different methods for data collection curtails the government’s ability to make realistic decisions regarding the capacity of hydropower plants.
• Install hydrological stations in strategic locations for long-term, reliable data of river discharge on the year-round hydrological cycle. One of the important components of hydropower design and operation is the information on dry season flow.
• Collate discharge data on sub-seasonal, seasonal, to multiyear basis, which can help forecast flow for managing and operating power plants in different seasons. Such data are generally applicable to reservoir type plants, where regulating reservoir capacity to store water is important.
• Address the data gap on extreme events such as glacial lake outburst, landslides, and avalanches.
• Initiate, encourage, and improve transboundary data sharing and dialogue through regional dialogues, given that major rivers in Nepal are transboundary.
• Generate data on the impact of hydropower on the hydrological cycle and aquatic ecosystem to check and balance the impact of hydropower on the environment. The information on the impacts of hydropower projects on aquatic ecosystems is limited, and current environmental flow is also mandated at 10% of the flow across the industry without considering the seasonal flow requirement of the river, geographical conditions, and aquatic ecosystems. Research on each basin and making such data accessible to hydropower developers can contribute to maintaining environmental sustainability.

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1. Hydropower experts including developers, government agency representatives, and researchers met to identify issues related to hydrological data and hydropower development. (Photo: Chimi Seldon/ICIMOD)