Optimized and adapted hydropower management considering glacier shrinkage scenarios in the Swiss Alps

Abstract

Global warming is an alarming reality and likely leads to an increase of multiple pressures on socio-economic systems. However, in high-mountain regions it might also become an opportunity to adapt existing hydropower schemes and future projects to this new reality. In the Alps, the melting of glaciers first produces over the near future an increase of the average annual discharge depending on glacier and catchment characteristics, especially during the summer season. Nevertheless after a certain time, significant decrease of runoff related to gla- cier melting must be considered for hydropower management. Moreover, the melted glaciers free new alpine valley areas, which have a potential for the construction of new dams and reser- voirs.
The opportunity to build new dams and hydropower plants downstream of retreating glaciers is studied systematically in Switzerland within the framework of the National Research Program on Sustainable Water Management (NRP61) under the project “New lakes in deglaciating high- mountain areas: climate-related development and challenges for sustainable use (NELAK)”. The developed methodology is based on several prediction models. Regional climate models provide spatially distributed rainfall and temperature scenarios for the next 50 years. The RS3.0 CLIMATE rainfall-runoff hydrological model computes the glacier evolution, the river dis- charge at the outlet of the catchment area as well as the hydropower production of the new lakes. Another model (GlabTop) is used to predict the future topography and geomorphology underneath the melting glaciers, in order to define the optimal locations of the future dams and reservoirs.
As a case study the Corbassière glacier near the Mauvoisin reservoir in Valais is presented. The opportunity of the construction of a new dam and a hydropower plant is studied, as well as its economic benefit and its impacts on the environment. The result of the case study provides a basis to assess the potential of investing in such projects to ensure the Swiss hydroelectricity production also in future.