Hydropower gains prominence
Since Switzerland elected to decommission its nuclear power plants (NPP), interest in hydropower has grown. Hydropower is indeed a largely ecological energy source but, like all other power sources, it has its downsides: flows below hydropower plants are altered, and the construction and expansion of small power plants partially offsets the effectiveness of restoration efforts. Hydropower plants also break up the continuity of streams and rivers, with negative consequences for fish. Pumped storage power plants provide electricity during peak times and during the winter, but they need more electricity to pump water back into the reservoirs then they produce themselves. Used in combination with wind turbines and solar power, however, pumped storage power plants would have a big advantage. The energy produced by wind and solar technologies could be used to drive the water pumps directly, a process that would help smooth out the variability of energy captured from the wind or sun. By further developing its wind, water and solar capacities, Switzerland could distinguish itself as the energy reservoir of Europe.
Over the next several decades, licenses to renew and expand hydropower plants will come due. The discussions and decisions about renewal permissions, reservoir extensions and so on will take place amidst environmental, social and economic concerns about how to best use limited water resources. Which sections of the river are valuable as recreation and refuge areas (leisure, fisheries, biodiversity)? Which should be protected for their scenic value? Which can be used for water management? How should high and low flows created during hydropower production be managed? To answer these questions, holistic decision aids (e. g. Hemund 2012) and the involvement of the affected population will be crucial.
Climate change alters the seasonal availability of water
Climate change will have an impact on snow and ice, which are key natural water reservoirs. In addition, a redistribution of rainfall is expected, with more precipitation in the winter and significantly less in the summer. Together, these changes will affect the seasonal distribution of runoff. Experts expect the peak discharge season to shift from the early summer to the winter months, and to last longer. Low water levels will become more frequent in late summer for most parts of the Central Plateau.
These changes in the water cycle will have economic consequences: the legal regulations for issues like water abstraction, the release of cooling water, the regulation of lakes, residual water amounts for hydroelectric power plants and many others will need to be checked. Because the risk of summer water scarcity is likely to increase, the water supply must be reconsidered. It must be determined if additional, multipurpose reservoirs will be needed to help meet future needs. River traffic on the Rhine is also likely to be affected by the increasing irregularity of discharge, particularly by low water levels.
Finding new ways
Despite the improving quality of water in Switzerland and the high security of the water supply, it is necessary to work together on sustainable water use:
- By combining different and currently independent water supply systems, the security of the supply would increase.
- Irrigation can be made more efficient by using better technologies, such as drip irrigation.
- The use of fertilizers and plant protection products (pesticides, herbicides, fungicides) must be reconsidered.
- The renewal or expansion of existing power plants should focus on reducing artificial fluctuations in discharge (“hydropeaking”) below the power plants.
- Restoration measures and improved discharge consistency from hydropower plants should help preserve and increase fish stocks.
Industry and commerce:
- Certain substances, such as hormones and nanoparticles from drugs and cosmetic products, create problems in the water cycle because conventional wastewater treatment plants cannot remove them. Sophisticated technical measures are required to dispose of micropollutants before they accumulate in the environment. The consequences of micropollutants for human, animal and plant health is difficult to estimate. What chemicals are really necessary? Which can be replaced by other, more biodegradable substances?
- The widely applied practice of separating rainwater and wastewater significantly relieves the pressure on wastewater treatment plants.
- The consolidation of smaller wastewater treatment plants allows for more efficient cleaning.
- New methods must be developed so that the smallest amounts of micropollutants can be found and removed from wastewater.