Swiss Geoscience Meeting, Geneva 2007

At the end of the 20th century, approximately 45’000 major dams have been exploited around the world for irrigation, hydroelectricity and as drinking water reservoirs (WDC 2000). Most of these dams and reservoirs have been evaluated and are monitored with respect to flood and seismic hazard, whereas environmental aspects linked to the sediment fill are not considered. In a series of applied and academic studies, the following reservoirs down stream of major Swiss cities have been investigated with respect to sediment quality and environmental impact: The Wettingen Reservoir, located on the Limmat River down stream from the city of Zürich, the Klingnau Reservoir on the lower Aare River, the Wohlen Reservoir down stream from Bern, the Verbois Reservoir down stream from the city of Geneva (Wildi et al. 2004). As a comparison with a natural lake, Vidy Bay (Lake Geneva), close to the city of Lausannne is also considered (Pardos et al. 2004, Poté et al. 2007). For almost all the contaminants and all the sediment cores investigated, one observes a general trend from either elevated or increasing values at the bas