Artificial Lowering of Glacial Lakes

Needs Address

• Prevent casualties and asset loss from GLOF
• Enhanced capacity of local organisations in handling DRR and CCA

Adaptation effects

Reduces the occurrence or severity of floods and landslides in adjacent areas as well as downstream

Overview and Features

A glacial lake outburst flood (GLOF) is a type of outburst flood due to the increased volume of water in the lakes as a result of increasing temperatures. For e.g. GLOFs have led to devastating loss of life and infrastructure in the Himalayas. Artificial lowering of water levels of lakes is a technique to reduce the risk of glacial outburst.

Cost

• Costs for equipment, human resources, and maintenance
• High costs (e.g. Thorthormi Lake project in Bhutan and Tsho Rolpa Lake project in Nepal range from $1 million to $3.2 million per lake (ADB, 2014)

Energy source

Fuel for excavation equipment

Ease of maintenance

Requires monitoring of lake levels and ongoing project inspection during and after implementation 

Technology performance

Lowering of lakes levels is most effective when combined with early-warning systems, preparedness training and planning

Considerations

• Adapting natural systems such as this can have negative impact in other areas; for example, reducing the flow of water upstream may result in   water shortage and drought downstream
• Excavation activities can be dangerous for workers, and proper safety precautions must be ensured
• Access to glacial lakes is often difficult and limited
• The cultural significance of glacial lakes must be considered in any activity that seeks to change its natural structure specially in South Asia

Co-benefit, suitability for developing countries

• Reduces need for resettlement of populations near flood areas, and therefore reduces livelihood disruption
• Increased storage capacity for water supply
• High costs mean government cooperation is crucial and overseas financial assistance is often required

Information Resources

ADB, 2014. Technologies to Support Climate Change Adaptation in Developing Asia. Asian Development Bank. Available at: http://www.adb.org/sites/default/files/publication/149400/technologies-climate-change-adaptation.pdf [12 January 2015]UNDP-ALM, 2012. Reducing Climate Change-induced Risks from Glacial Lake Outburst Floods in Bhutan. Available at: http://www.undp-alm.org/projects/ldcf-glof-bhutan [20 March 2015]

UNFCC, 2012. Expert meeting on a range of approaches to address loss and damage associated with the adverse effects of climate change, including impacts related to extreme weather events and slow onset events, 27–29 August, 2012, Bangkok, Thailand. Available at: https://unfccc.int/files/adaptation/cancun_adaptation_framework/loss_and_damage/application/pdf/info_sheet_templateglof_tshorolpa_icimod.pdf