Floods

Floods are one of the most typical demonstrations of hydrogeological instability and are caused by watercourses which, with water in excess of the normal flowing through, burst their banks or else overflow them, invading the surrounding areas and incurring damage to buildings, industrial sites, roads, railways and farmlands.

The major floods in Italy creating the heaviest results, in terms of loss of human lives and damages, were those of the Po Valley Polesine area (1951), River Arno (1966) and River Po Valley in Northern Italy (1994 and 2000).

The elevated anthropogenic activities and widespread impermeability of the territory, which, by preventing rainwater to filter into the terrain, increase the quantity and speed of water flowing into the rivers, are amongst the causes of the increase in the frequency of floods in Italy. Failure to keep the beds of the latter clean and invasive debris and vegetation creating difficulty for water to flow through under normal conditions, are another major cause.
Many hydrographic basins, particularly in Liguria and Calabria, typically take only a few hours to reach peak levels.

It is therefore essential to alert institutional bodies in the area as far in advance as possible, to reduce exposure of persons to the events and limit damages to the territory.

An efficient defence is based on both structural solutions, such as building up embankments, reservoirs, by-pass canals, straightening out bends, as well as non structural solutions, such as those for controlling the territory or emergencies: in the latter case it is essential to prepare prediction systems connected to a network of monitors, draw up emergency plans and organize an efficient coordination system for the activities provided in said plans.