The rain gauge is correct: 35 centimeters of water (it’s the annual average value reduced to 1/6) fell on the upper Romagna from Tuesday to Thursday (48 hours). The event registered last week was tragic: helicopters (Armed Forces) mobilized to help 2500 displaced citizens, homes and businesses destroyed by the stream of floods in the area affected by the flood (45 centimeters of rain over 15 days) of May 2023. The annual frequency (1%) on the return extracted from the analysis of historical sequences has been denied by the last wave of extraordinary bad weather: the most recent similar episode dates back to 1939. The mass of rain induced by climate change is unsustainable to the streams defined by the narrow and constrained shore of the Romagna valleys: today water demands more space besides expansion basins, low-lying floodplains, cleaning of rivers and ditches. Forecasting, monitoring and warning reduces the cyclical disaster.
The Napoleonic Cable was effective in alleviating the distress on the alluvionated territory (2023): water (200 million cubic meters) flowed to the river Po from the canal (18 km) conceived (1805) and activated (1966) to supply the scolmatore to the river Reno and then irrigate the Canal Emiliano Romagnolo (CER) alias the water carrier destined to civil and industrial structures diffused in the territory defined also by hydro-demanding agriculture. The artificial canal (30 km) Cavo Benedettino suggested by Cardinal Prospero Lorenzo Lambertini (Bologna, 31 March 1675 – Rome, 3 May 1758) then Pope Benedict XIV to join the branch Po di Primaro to the river Reno was weak to protect the plain of Bologna from flodding. Napoleon was pushed by the commission chaired by the lawyer Antonio Aldini (Bologna, 27 December 1755 – Pavia, 30 September 1826) then Secretary of State to the Kingdom of Italy to issue the decree to cancel the debt to the Department of the Rhine and build the ten-mile line. Today the infrastructure, unfinished (1814) because the budget (3.12 million lire) was untenable for the French Empire exhausted by military campaigns (Russia and Spain), is joined to the CER and equipped with a trapezoidal section to raise the water flow to one thousand cubic metres per second. The test was carried out (1966) also to reduce the disastrous floods recorded from 1949 to 1951.
