Increasing cryospheric hazards and sediment supply threaten water quality and hydropower systems in high mountain areas
- 1Department of Geography, National University of Singapore, Kent Ridge 117570, Singapore
- 2Department of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
- 3International Centre for Integrated Mountain Development, Kathmandu, Nepal
- 4College of Science and Engineering, James Cook University, Cairns, Queensland, 4878, Australia
- 5College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9EZ, UK
- 6International Water Management Institute (IWMI), Kathmandu, Nepal
- 7Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China
- 8Faculty of Geosciences, Department of Physical Geography, Utrecht University, Utrecht, The Netherlands
- 9Water, Sediment, Hazards, and Earth-surface Dynamics (waterSHED) Lab, Department of Geoscience, University of Calgary, Alberta, T2N 1N4, Canada
- 10Department of Geography, University of British Columbia, Vancouver, BC V6T1Z2, Canada
- 11Institute of Earth Surface Dynamics, University of Lausanne, Lausanne CH-1015, Switzerland
- 12School of Geography and Sustainable Development, University of St Andrews, St Andrews, Scotland, KY19 9AL, UK
Global warming-induced melting and thawing of the cryosphere are rapidly changing hydrogeomorphic processes and cryospheric hazards in high mountain areas worldwide. These processes and hazards include glacial retreat and collapses, permafrost thaw and associated landslides, rock-ice avalanches, debris flows, and outburst floods from glacier lakes and landslide-dammed lakes. The changing slope instability and extreme flood have accelerated landscape erosion and increased fluvial sediment loads. For example, the rivers in High Mountain Asia are becoming muddier due to increased suspended particulate matters from melting glaciers and thawing permafrost, likely degrading water quality as fine-grained sediment are easily bonded with organic carbon, phosphorus and most heavy metals (e.g., mercury, chromium, arsenic and lead). Importantly, numerous hydropower dams and reservoirs are under construction or planning in high-mountain areas worldwide such as in the Himalaya and Andes. The increasing amounts of mobilized sediment can fill up reservoirs, cause dam failure, and degrade power turbines, threatening the short-term safety and longer-term sustainability of these hydropower systems.
In the future, we recommend forward-looking design and maintenance solutions that can help transition towards climate change-resilient high-quality water supply and hydropower systems in high-mountain areas. The specific suggestions include: (i) monitor the climate, glaciers and permafrost, glacial lakes, unstable slopes, discharge and sediment yields to better understand the cascading links between climate change, glacier retreat and hazards; (ii) predict future fluvial sediment loads, water quality and reservoir sedimentation in a changing climate and develop sustainable sediment management solutions; (iii) establish real-time early warning systems and enhance social awareness and drills, especially for in-construction dams to minimize human and infrastructure losses; (iv) enhance transboundary cooperation by establishing data-sharing schemes and adopting joint-operation strategies to better cope with hazards and optimise sediment flushing; and (v) promote the inclusion of indigenous and local knowledge in policy, governance, and management for water quality assessment and dam and reservoir construction.
The major results of this study have been published online: Li, D., Lu, X., Walling, D. E., Zhang, T., Steiner, J. F., Wasson, R. J., ... & Bolch, T. (2022). High Mountain Asia hydropower systems threatened by climate-driven landscape instability. Nature Geoscience, 15(7), 520-530. https://doi.org/10.1038/s41561-022-00953-y
How to cite: Li, D., Lu, X., Walling, D., Zhang, T., Steiner, J., Wasson, R., Stephan, H., Nepal, S., Nie, Y., Immerzeel, W., Shugar, D., Koppes, M., Lane, S., and Bolch, T.: Increasing cryospheric hazards and sediment supply threaten water quality and hydropower systems in high mountain areas, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-2549, https://doi.org/10.5194/egusphere-egu23-2549, 2023.
