90 m3/ha in 1981, and further diminished in 2006, where we estimated an average storage capacity of 22.10 m3/ha. The implementation of the urban drainage system, with a storage capacity of about 0.23 m3/ha, and a total storage of about 15 m3 over the whole surface, cannot compensate for the storage volumes that have been lost during the years. As shown in Fig. 11, the estimated value of CI (0.64) for the rainfall station next to the study area is in line with the values of CI published by the Veneto region considering 14 different rainfall stations all over Veneto for
the timeframe 1956–2009 (Consiglio Regionale del Veneto, 2012). For the whole Veneto Region, the CI values range from a minimum 0.57–0.60, found in the locality PARP inhibitor trial belonging to the western plain, to
a maximum of 0.65–0.67 recorded both in the lower part of the floodplain, and the eastern bottom side of the Alps (Consiglio Regionale del Veneto, 2012). The CI value for the Este station is among the highest values of the whole floodplain (maximum measured value of CI is 0.65 for the rainfall station in Legnaro, near Padova). The study result seems to be in line with the work Carfilzomib order of Cortesi et al. (2012) that found CI values ranging from 0.57 and 0.66 in the north-eastern Italian floodplain for the period 1971–2010. The Veneto Region provides also an overview of how the CI changed over time, considering different time spans: 1956–1969, 1970–1989 and 1990–2009 (Consiglio Regionale del Veneto, 2012. Given the good correspondence between the calculated CI value
for the years 1955–2012, and the one provided by the this website Regional Government (see Fig. 11), we extrapolated from the Regional maps the Este CI value for the other time-frames. According to this analysis, the Este CI values was equal to 0.61 in 1956–1969 and 1970–1980, but it increased to 0.63 in the 1990–2009 timeframe. This increasing trend seems to be in line with the trend registered by the already mentioned Cortesi et al. (2012) study, whose results underlined (however without a statistical significance) a slight positive trend in the annual index over the years in the north-eastern Italian floodplain. On the other hand, different studies (Brunetti et al., 2000a, Brunetti et al., 2000b, Brunetti et al., 2000c and Brunetti et al., 2001) underlined for northern Italy an increase in the mean precipitation intensity for the most recent years, mainly due to a strong positive trend in the contribution of the heavy daily precipitation events. For the Veneto region, in particular, a recent work on extreme meteorological phenomena highlighted how, starting from the 1980s, the occurrence of intense rainfall has progressively increased (Bixio, 2009). From the 1980s to 2007, according to Bixio, this progression led to the progressive halving of the estimated time of recurrence of extreme events.