Flash Flood Events and Urban Development in Genoa (Italy): Lost in Translation

Abstract

Coastal locations in the Mediterranean area experienced several geo-hydrological events from the beginning of the 3rd Millennium. Among the most flooded areas featuring the Ligurian coastal environment, Genoa is sorrowfully at international level, for the flash flood characteristics and consequent damage: the last event of 4 November 2011, once again, caused the loss of human lives. Genoa, in fact, can be considered an interesting case study for geo-hydrological risks: it can be said that to a general trend of increasing hazard, due to global and particular climate changes of the Mediterranean area, corresponds an increase of the vulnerability due to the urban growth on the flood plains. In this paper are analyzed the unusual meteorological characteristics of the Gulf of Genoa, the changes in the rate of daily precipitation using the recorded data at the station of Genoa, in use since 1833. The most significant periods of the land urban development are also briefly described. They have determined important changes of the territory, modifying the water balance of the basins in a considerable wa

A multi-component flood risk assessment in the Maresme coast (NW Mediterranean)

“…Vinet 2008). This is also common for most of the Mediterranean coastal zone (Ruin et al 2008;Llasat et al 2010a, b;Faccini et al 2015).…”

Geohydrological hazards and urban development in the Mediterranean area: an example from Genoa (Liguria, Italy)

“…It is noticeable that the events that occurred in 1970 and 1993, which had affected a wider area, are those which suffered the greatest economic damages; while there were fatalities in all the episodes, with the largest number resultant of the disastrous flood of October 1970. The weather conditions in all these events were characterized by a blocking anticyclone to the east and a deep trough to the west (as described by Bossolasco et al (1971) for the 1970 event), producing prefrontal storms on the warm branch of the perturbation (Faccini et al, 2014(Faccini et al, , 2015a. The following paragraphs describe the specific consequences of these six events.…”

“…The two factors that determine the geological risk are subsequently analysed: the incidence of short and intense rainfall events and the vulnerability determined by the urban sprawl (Faccini et al, 2014). The rainfall incidence was assessed primarily by using the climatic data of the time series recorded by the centuries-old station at Genoa University.…”

“…The convergence of these air masses and the wind shear trigger the development of mesoscale convective systems (Silvestro et al, 2012). These convective systems have recently affected different locations Tropeano et al (1993Tropeano et al ( , 1995; Faccini et al (2014Faccini et al ( , 2015a over the Ligurian Gulf , causing flash floods arising from rainfall intensities of over 500 mm/6 h or 180 mm/1 h. The most recent of these events occurred on November 2014 in Genoa. These phenomena have been recurring and have been particularly violent in recent years, especially the last events that took place in Varazze and Sestri Ponente, Genoa, in 2010 (Faccini et al, 2015b), Cinqueterre (Cevasco et al, 2013;Buzzi et al, 2014) and Bisagno Valley, Genoa, in 2011 (Brandolini et al, 2012) and 2014 (Faccini et al, 2015a, c).…”

“…In Genoa also Sturla (o), Fereggiano, Noce (tributaries of the Bisagno stream) and Torbella creeks (tributary of the Polcevera stream) overflowed, so neighbourhoods west of the centre and east of the centre were inundated. All these events have impacted a narrow band of territory affected by a convective system as evidenced by the radar images and the isohyets of the event (Cati, 1971;Tropeano et al, 1993Tropeano et al, , 1995Faccini et al, 2014Faccini et al, , 2015a.…”