A comprehensive maintenance program for the conservation of the historical centre of Venice

The survival of Venice in the very difficult environmental conditions of its lagoon has been for centuries ensured by a complex combination of construction techniques and maintenance procedures. The attention paid by the Republic to the efficiency of the canals within the lagoon and the city itself is very well known and a tight correlation exists between the working conditions of the canals and the conservation of the urban fabric. The municipality of Venice recently resolved to start a very comprehensive maintenance program of the historical centre that has the clearing up of mud from the canals as its first basic step. The operation, systematically carried out in the past, has been abandoned for decades and the consequences of that are creating very serious environmental problems. In the paper the general context in which the program has been planned is explained, also referring to the financial and management aspects. The substantial hygienic aspects due to the system through which waste waters are taken from the buildings and to the composition of the sediments are also presented. The technical aspects, comprising those related to the execution of a pilot-intervention, are then described. Lining the canals are private and public buildings and streets, squares and bridges (masonry and cast iron made) which generally require repair and strengthening