Water resources are decreasing in Italy: in 2023 annual water availability decreased by 18.4% compared to the average
Sicily Region with the least rainfall, Friuli Venezia Giulia the rainiest
The ISPRA Report "National hydrological balance: BIGBANG estimates and indicators on water resources" has been published
In 2023, the total annual precipitation relating to the national territory, with almost 924 mm, corresponding to approximately 280 billion cubic metres, recorded an increase of 28.5% compared to 2022, the year in which the peak was reached with approximately 719 mm. historic low from 1951 to today. However, compared with the average precipitation over the long period 1951-2023 (almost 950 mm), that of 2023 is slightly decreasing.
Why this increase compared to 2022? Mainly due to the high volume of rainfall in the month of May 2023, estimated at almost 163 mm, around 49 billion cubic metres, which was, at a national level, more than double what on average characterizes the same month (around 23 billion cubic meters in the long term).
This is what emerges from the assessments produced by ISPRA through the BIGBANG model which provides the national hydrological balance, the quantitative picture of the water resource and, more generally, the hydrological situation in 2023, reconstructing trends and differences compared to the long-term average values of 1951 -2023 and the thirty-year climatological period 1991-2020.
BIGBANG estimates show that in 2023 the contribution to aquifer recharge in Italy was 53 billion cubic meters (corresponding to 19% of rainfall), compared to an annual average of 22.7% over the period 1951–2023. The amount of precipitation that was transformed into surface runoff - that is to say that it did not infiltrate or was not retained by the ground - is estimated at approximately 66 billion cubic metres, corresponding to 23.7% of the precipitation, compared at an average annual rate of just over 25% over the long term. The share of evapotranspiration reached 59.4% of precipitation, compared to the long-term annual average which amounts to approximately 52%. This was caused by the high temperatures, higher than the reference climatological averages, which also occurred in 2023
National hydrological balance: BIGBANG estimates and indicators on water resources. Update to 2023