Swiss dams: Overview of historical development

With more than 220 large dams in operation, compared to its surface of some 41ʹ000 km2, Switzerland has a very large fleet. They were erected to meet various economic and protection needs. Their main assignments concern the storage of water for later use, mainly hydropower, and the protection of property, particularly against floods. It is from the 19th century with the growth of the population and the industrial development that the marked beginning of the construction of large dams. This paper describes, over time, the various stages of this development, the main period of which is between 1950 and 1970. Guaranteeing the safety of these storage schemes at all times is essential. A concept based on three pillars (structural safety, monitoring and maintenance, emergency plan) was developed. Periodic safety assessments have led to the undertaking of maintenance and rehabilitation works for several storage schemes. In the future, the monitoring and uprating of existing structures will remain an important task. New projects with the purpose to increase storage for the winter critical season are also planned and are partly already integrated into an expansion process, in particular to meet actually needs for a safe and low carbon energy transition. Of course, research and development remain specific objectives to maintain the competences of dam engineering not only in Switzerland but also for the participation to worldwide development of dams and reservoirs.