Modernisation of the drinking water supply in Kopfholz
STRABAG has started a modernisation project at the Kopfholz drinking water reservoir to supply water to the Zurich municipalities of Horgen, Thalwil, Rüschlikon and Kilchberg. Special constructional features have to be taken into account. Construction is planned during ongoing operations and represents a logistical challenge.
The Schlieren-based construction company STRABAG has begun dismantling and rebuilding the Kopfholz reservoir on behalf of the municipalities of Horgen, Thalwil, Rüschlikon and Kilchberg. According to a statement from STRABAG, the modernisation project is intended to secure the local drinking water supply until 2050. In order to ensure a continuous supply of water, three construction phases are planned for the planned replacement construction. The first construction phase is to be completed by February 2026, with the project scheduled for completion in March 2027.
According to the press release, the municipalities have been operating a joint water supply since 1905. The connection will be continued with the project, which the municipalities believe sends a “strong signal for a sustainable, safe and future-oriented water supply”. Rüschlikon’s storage capacity is expected to increase from 1000 to 1600 cubic metres, and Kilchberg’s from 1500 to 2800 cubic metres.
The press release emphasises the particular challenge faced by the construction teams from the four clients in building the reservoir during ongoing operations. “The reservoir supplies more than 6,000 households with drinking water and the supply must be guaranteed at all times,” Beat Spörndli, Construction Manager, Civil Engineering and Road Construction North-East, is quoted as saying. He also emphasised the “high demands on coordination and hygiene on the construction site”. In addition to compliance with SIA standards (Swiss Society of Engineers and Architects), the use of a special drinking water concrete is a prerequisite. As the construction is subject to the Foodstuffs Act, germ-free water storage must be ensured. The close cooperation between the municipalities enables coordinated planning, minimises interference with the forest area and triggers synergies in tenders and construction processes.