ABSTRACT
From 1984, year of first application on an RCC dam, the use of synthetic geomembranes to provide upstream impermeability has constantly increased. In 2003, up to a total of 27 RCC dams incorporate a synthetic geomembrane. The reasons for such growth are to be found in the technical and financial effectiveness of the system, and in its proven durability. The paper describes the exposed system, installing the geomembrane over the completed RCC lifts, the covered system, embedding the geomembrane in concrete panels that serve as permanent formworks for construction of the dam, and the exposed geomembrane system adopted as external waterstop on vertical contraction joints and as repair system for new cracks. Concepts, statistics, and construction details of the system at Miel I, Olivenhain, Porce II and Platanovryssi dams are presented.
