The Pavana mixed type dam was built in the years 1923-1925. The central part consists of a multiple arch dam on buttresses, the left part is a caisson type and the right is a concrete gravity structure. The spillway is an independent structure, located upstream of the dam on the right bank and consist of two vanes, one with a sector gate and the other with an automatic flap gate. The spilled discharge is collected in a basin, and by means of a vertical vortex shaft is evacuated into the outlet tunnel. The same outlet tunnel receives the discharge from the intermediate outlet. The bottom outlet is located between the dam and the spillway structure. Its inlet is regulated by two hydraulic gates and the water is released downstream by an independent tunnel. The concrete of the structure is subject to expansive alteration phenomena due to alcal aggregate reaction (AAR), with visible cracks on the arches and buttresses. Lombardi has been awarded with the revision of the final design and the construction design of the rehabilitation works. After completion, the historical arch-buttress static scheme will be converted in a gravity dam, preserving part of the original concrete. Structural joints will be realized to avoid adverse transmission of loads between existing and new parts. A new drainage scheme will be implemented. The design activities include the verification and seismic enhancement of the dam and its appurtenant structures. Lombardi Ltd. is also in charge of environmental assessments, support for authorizations, site supervision and related technical assistance.