The project includes the xxx for the maintainance of the functionality and safety procedures for the drainage of Casanova dam on Chiascio river. In particular, the retaining structures aimed to the enlargement of the artificial drainage tunnel have been analyzed. The artificial tunnel is contained between two bulkheads of piers (Ø1200 ) and contrete beams on the top, with a pitch of 3.90m while on the bottom they are clamped in the bedrock.