Dr. Rijan Bhakta Kayastha

Glacial Hazards in the Nepal Himalayas

Dr. Rijan Bhakta Kayastha
Himalayan Cryosphere, Climate and Disaster Research Center (HiCCDRC)
Department of Environmental Science and Engineering, School of Science, Kathmandu University, Dhulikhel, Kavre, Bagmati Province, NEPAL

Nepal is rich in water resources because of its monsoon, snow-covered area, and a number of glaciers in the Himalayas. However, the hydrological responses of the snow-covered and glaciated zones are distinct from the other zones of Nepal. The water resource of Nepal is heavily dependent on monsoon dynamics and the state of the snow and glacier ice in the Himalayas. Climate change affects both monsoon dynamics and snow and glacier ice in the Himalayas. In addition to this, climate change is also responsible for the increasing number of glacial hazards recently in Nepal. 

Glacier is a moving body of snow and ice that has been formed as a recrystallization of snow and a glacial lake is a lake that is formed by glacial activity. Glacial hazard includes any hazard in a glaciated region such as snow and ice avalanche, flash flood due to supraglacial lake draining, and rapid melting of snow and ice of a glacier, Glacial Lake Outburst flood (GLOF), ground subsidence due to rapid thawing of permafrost and heavy snowfall in a glaciated region, etc. 

Many studies have shown retreat of glaciers, expanding existing glacial lakes and forming new lakes and altitude of a lower limit of permafrost are shifting upward in the Nepal Himalayas. There are 19 glacierized sub-river basins from east to west in which there are 3,808 glaciers and 2,070 glacial lakes in Nepal (Bajracharya et al., 2020). Total 47 glacial lakes in Nepal, Tibet, China, and India are classified as Potentially Dangerous Glacial Lakes to Nepal because if these glacial lakes are drained, the flood water will enter into Nepal and damage considerably. Out of 47 potentially dangerous glacial lakes in the Himalayas, 25 are in Tibet, China, 21 in Nepal, and 1 in India. This renders much of the infrastructure along the rivers originating from these lakes at immediate risk.

A 2011 study by ICIMOD reported 24 GLOF events in the past, 14 of which had occurred in Nepal, while 10 were caused by overspills due to flood surges across  China (TAR)‒Nepal border (ICIMOD, 2011). On 4 August 1985, a Dig Tsho GLOF event swept away three persons, one hydropower plant, 14 bridges, and 35 houses along the Dudh Koshi River. Table 1 shows major GLOF events since the 1980s that have caused damages in Nepal. Since GLOF events are increasing recently, in order to reduce the risk from such events again the Department of Hydrology and Meteorology, Government of Nepal has reduced the water level of Tsho Rolpa Glacial Lake in Dolakha district by 3 m in 2000 and that of Imja Glacial Lake in Solukhumbu district in 2016 by 3.4 m successfully.  

Table 1. GLOF events since the 1980s that have caused damages in Nepal.

S. No.DateRiver basinLocation
123 June 1980TamorNagma Pokhari
211 July 1981Bhote KoshiCirenmacho Lake, Zhangzangbo Valley
34 August 1985Dudh KoshiDig Tsho
412 July 1991Tama KoshiChubung
53 September 1998Dudh KoshiSabai Tsho (Tam Pokhari)
65 July 2016Bhote KoshiTAR, China
720 April 2017Barun ValleyNear Lower Barun

In the recent past, also a few flash flood events in the glacierized river basins of Nepal are occurring mainly due to irregular monsoon activity and sudden warming epochs in some regions. Seti flash flood on 5 May 2012 due to snow, ice, and rock avalanche, a Glacial Lake Outburst Flood (GLOF) on 5 July 2016 in Bhotekoshi River in Tibet, China, and a flash flood on 20 April 2017 in Barun River are a few examples. Such events have increased the risk of glacial hazards, especially in the high mountain areas. Therefore, it is high time to monitor weather, snow, glaciers, glacial lakes of the high Himalayas by establishing suitable stations and need to install  early warning systems in downstream of such glacierized river basins in Nepal. 

Snow and weather monitoring stations at high altitudes will be also useful to analyze possible snow hazards and then flash floods in the downstream as such occurred in Seti River in Nepal on 5 May 2012, heavy rainfall resulting rapid melting of snow and ice from Chorabari Glacier in Kedarnath, India on 16 June 2013, heavy snowfall by Cyclone Hudhud on 13 October 2013 in the Annapurna region, Nepal, and the recent Chamoli flash flood in Uttarakhand in India on 7 February 2021 due to snow, ice, and rock avalanche. Since weather, snow, glacier, and glacial lake monitoring stations are very rare in the Nepal Himalayas, it is very high time to establish such stations across Nepal to reduce and prevent damages caused by glacial hazards in Nepal.


Bajracharya, S. R., Maharjan, S. B., Shrestha, F., Sherpa, T.C., Wagle, N., Shrestha, A. B.

(2020). Inventory of glacial lakes and identification of potentially dangerous glacial lakes in the

Koshi, Gandaki, and Karnali River Basins of Nepal, the Tibet Autonomous Region of China, and

India. Research Report. ICIMOD and UNDP.

ICIMOD (2011). Glacial lakes and glacial lake outburst floods in Nepal. Kathmandu: ICIMOD.
Note: ‘Young Researcher’ Issue 05 – May 2021

Bhesh Raj Thapa

Groundwater Governance Prospects and Challenges in Nepal

The set of framework and guiding principles that provide an environment for collective management of groundwater for sustainability, equity, and efficiency can be understood as groundwater governance. The groundwater resources vary widely with natural variation and geological heterogeneity. Therefore, governance must be adapted to the local context. Groundwater, being an integral part of the hydrological cycle, needs to be managed in conjunction with linked water and land resources. Over time, groundwater extraction in Nepal for different purposes has been growing gradually (driven by demography, technology, and changing lifestyles), resulting in threats to its sustainability. This indicates that sound governance is a pressing priority. However, the development and implementation of several components of the governance are creating a larger governance gap.  

 Er. Bhesh Raj Thapa
International Water Management Institute

In Nepal, intensive groundwater extraction, pollution by inadequate sanitation and wastewater treatment, pollution by industry and agriculture, inequitable allocation, inefficient use, and land subsidence are the key issues and challenges for groundwater management, mainly in bigger cities and the Terai area. In addition to this, the role of groundwater actors and their mode of interaction, regulatory and institutional framework, policies development, and their implementation is not well understood and not in function. Such frameworks and policies need to be revisited for good governance in the groundwater sector. Although several water-related laws and regulations focusing on groundwater have been made, groundwater has practically remained an unregulated resource in Nepal.

The cities like Kathmandu have been facing negative consequences like drying of traditional water sources, decreasing well yields, and declining groundwater levels due to excess extraction rather than recharge. Groundwater act, regulation, and policy exist, but the mechanism and dynamics of changes for sustainable management of groundwater have not been properly addressed till date. Overlapping responsibilities and sectoral conflicts in water institutions in most of the major cities are causing weak governance in the water sector. In addition to this, poor understanding of hydrological dynamics of conjunctive water use and local hydro-geological complexities are also major constraints for sustainable groundwater management through policy formulation and implementation.

Improving groundwater governance is not easy, hence the responsible local institutions have to make their judgement based on the regulation and policies to suggest feasible and effective measures in the current situations. All the relevant parties need to commit and cooperate towards a common goal for effective groundwater governance. Good governance will mainly be guided with four sets of principal and consideration: political and institutional (accountability, representation, consistency, institutional capacity etc.); socio-cultural (religious and spiritual traditions, social learning, social inclusion, ethics etc.); economic (price signal, groundwater storage condition, water quality impacts, willingness to pay etc.); ecological (storage, attenuation rate and renewability, land uses etc.). To improve the groundwater governance, it needs to be treated in a holistic approach and proper management instrument and measures need to be selected based on the local condition. Their effectiveness not only depends on the local physical, institutional, economic and social condition but also on the way these measures are designed and implemented. In addition to this, information and knowledge regarding local conditions need to be shared and awareness related to the baseline of the groundwater resources and their safe limit need to be raised for good groundwater governance. Reaching an effective level of awareness is the first step towards structural communication between decision-makers, planners, groundwater specialists and stakeholders. For adequate groundwater management, a powerful and effectively operating groundwater organization is a must. In addition to this, the laws related to groundwater allow for a connection between the policies of groundwater and those of the related field such as surface water management, land use planning, and environmental protections.

Note: ‘Young Researcher’ Issue 04 – Jan 2021