29.04.2013

Switzerland: No water shortage despite melting glaciers

WSL staff Bruno Fritschi installing instruments in the Damm riverbed. Photo: WSL

Glaciers melt, lakes remain. Photo: Marcia Phillips / WSL

At the yearly media conference of the ETH Board,  WSL-Director Konrad Steffen held a presentation on the topic of

Switzerland: Europe’s surge tank

Switzerland is Europe’s surge tank. Nearly four times the annual volume of precipitation (an average of 146 cm per year) is stored in lakes, groundwater, snow, glaciers and rivers. Switzerland possesses over 6% of the continent’s fresh water reserves although it accounts for only 0.6% of its area. Some 200 reservoir lakes supply 30% of the country’s electric power needs. Even today, these reservoirs also play an important role in regulating water flows and preventing floods.

Model calculations and experiments of this sort are carried out at the Laboratory of Hydraulics, Hydrology and Glaciology (VAW) at ETH Zurich. Prof. Konrad Steffen, director of the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), is convinced that this role will become more important in future. "With climate change, the role of glaciers as water reservoirs and summer water sources diminishes. Reservoir lakes have to assume a portion of these functions, and their retention capacity in the event of heavy precipitation will also become more important."

Even with climate change, Switzerland as a whole will have an excess of water. "Our models show that stocks will decline, but no model shows them falling to zero. And the total outflow volume remains roughly equal. Still, palpable consequences are to be expected regionally and seasonally. While outflows in the high mountain regions will increase slightly, in Ticino they will decline significantly." Peak outflows will occur earlier in the year since higher temperatures will result in earlier melting of snow cover. At the same time, the weather will continue to vary from year to year in future. "This year there was above-average snow cover almost everywhere", says Konrad Steffen. "On the weekend of 20–21 April too there was snow on the ground even into the flatlands. Isolated extreme events are possible today and in future.”

• Full text of the ETH Board media release
  
• Presentation von Prof. Dr. Konrad Steffen "Die Schweiz als Wasserschloss" (in German)
  

Contact

• Gottardo Pestalozzi