ABSTRACT
The Rigoso project includes two dams (Lake Verde and Lake Ballano), built in 1907-8 for hydroelectric purposes, in stone masonry and based on morainic debris. Over the years, interventions have been made to strengthen the dam sections, necessary for the water losses of the foundation. Currently the two works are in disuse due to drastic reservoir limitations imposed by the Italian agency for large dams. The need to fix them definitively and to partially recover their hydroelectric use prompted the Operator, Enel Green Power, to plan their substantial restructuring, which involves reducing the height, making the structures safe with interventions to consolidate facing and foundations, the creation of an adequate drainage system. As a result of the reduction in height, the project is configured as a partial decommissioning. The design had to face not insignificant challenges, given that the constraint of implanting a new project over a century old works, based on permeable loose soils, requires greater accuracy than those required in the design of new works. A further challenge is added to the technical requirements, in fact the two works are located in a Regional Park, and therefore any demolished material must be classified and recovered in the works.
