Meltwater temperature in streams draining Alpine glaciers

Williamson, RJ; Entwistle, NS; Collins, DN

Abstract

Water temperature is of considerable importance with respect to lotic habitats. Water temperature influences physical, chemical and biological conditions within river environments and is, therefore, a key determiner of the health of a river. Climate change is significantly impacting lotic environments, through changes to hydrology, biodiversity and species distribution. Effects of climate change are greatest at high elevation and biota in and around glacier-fed rivers is likely, therefore, to be at great risk. How climate change influences the hydrology will have great impact on river water temperature and glacier-fed rivers in Alpine environments are extremely sensitive to climatic change. This paper assesses five rivers: Four glacier-fed rivers (36.9 - 82% percentage glacierisation) located in the Swiss Alps, and one located in an ice-free catchment in the Bernese Oberland, Switzerland. The aim was to assess the impact of basin characteristics on river water temperature. A distinct paradoxical relationship was
identified whereby water temperature in some glacier-fed rivers was reduced during the time of highest incoming shortwave radiation receipts and high air temperature. Whether a summer cooling effect presented itself in all
glacier-fed rivers within this study was researched. The key findings were that the identified summer cooling effect was not present in all rivers, despite percentage glacierisation. Percentage glacier cover has often been reported as they key determiner of water temperature in such rivers. More important was the stream dimensions, notably stream surface area. Understanding the controlling factors that influence water temperature of glacier-fed rivers will help river managers and planners in knowing how climate change will impact fisheries downstream of glaciers over the coming decades. This may allow plans to be introduced to try and mitigate warmer water temperature that will result, in some glacier-fed rivers, as the climate warms.

Citation

Williamson, R., Entwistle, N., & Collins, D. (2018). Meltwater temperature in streams draining Alpine glaciers. Science of the Total Environment, 658(Mar 19), 777-786. https://doi.org/10.1016/j.scitotenv.2018.12.215

• Journal Article Type: Article
• Acceptance Date: Dec 14, 2018
• Online Publication Date: Dec 18, 2018
• Publication Date: Dec 18, 2018
• Deposit Date: Nov 9, 2018
• Publicly Available Date: Dec 18, 2019
• Journal: Science of the Total Environment
• Print ISSN: 0048-9697
• Publisher: Elsevier
• Volume: 658
• Issue: Mar 19
• Pages: 777-786
• DOI: https://doi.org/10.1016/j.scitotenv.2018.12.215
• Publisher URL: https://doi.org/10.1016/j.scitotenv.2018.12.215
• Related Public URLs: https://www.journals.elsevier.com/science-of-the-total-environment