Flooding can be caused in various ways, by water flowing over quaysides and embankments, by seepage through the ground, or by flowback through drains.
Local defence is obtained by raising the lowest lying parts of urban areas by means of complex measures including the raising and structural consolidation of quaysides, embankments and public paved areas; protection of ground floor property and rear-lying private and public areas such as courtyards and gardens from flooding and reorganisation and adaptation of the network of underground infrastructure and the drainage system to avoid flowback through drains.

However, raising has precise limits beyond which it is impossible to proceed.
Local defence is thus integrated with the sistem of works to regulate tidal floods. To oppose deterioration of banks, canal walls and quaysides in the lagoon and inhabited areas, long section of these structures (that have either deteriorated or are too low in relation to the water level) have been consolidated and at times restructured.