Monitoring

Water: Ispra, in 2023 in Italy -18.4% of water resources

Sicily was the region with the least rainfall, while Friuli Venezia Giulia was the rainiest area in Italy

7 November 2024

3' min read

Water resources are dwindling and water availability is decreasing. In 2023 in the national landscape, the reduction was18.4% compared to the average. And although there has been a slight increase compared to 2022, the amount of water resources is still below the average of past years. The case of Sicily, the region with the least rainfall, and Friuli Venezia Giulia, the rainiest area in Italy, are also in this picture.

The Ispra report

The picture emerges from Ispra's 'National Hydrological Balance: Bigbang Estimates and Water Resource Indicators' report. The study shows that although 2023 recorded an increase of 28.5 per cent compared to 2022 (the year in which the historical minimum since 1951 was reached with 719 millimetres), with the almost 924 millimetres of total annual precipitation in the national territory and thus 280 million cubic metres, we are still below the average of almost 950 millimetres for the period from 1951 to date.

For the researchers, the increase compared to 2022 is due "mainly to the high volume of rainfall in May 2023, estimated at almost 163 millimetres, about 49 billion cubic metres, which was, nationally, more than double the average volume of rainfall in the same month (about 23 billion cubic metres over the long term)".

Framework from 1951 to 2023

The study, which uses the Bigbang model, 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 average values of the long period 1951-2023 and the 30-year climatological period 1991-2020".

In 2023, 'the contribution to aquifer recharge in Italy was 53 billion cubic metres (corresponding to 19% of precipitation), compared to an annual average of 22.7% over the period 1951-2023'. However, this is not all. "The amount of precipitation that has been transformed into surface runoff, i.e. that has not infiltrated or been retained by the soil," the report highlights, "is estimated at about 66 billion cubic metres, corresponding to 23.7% of precipitation, compared to an annual average rate of just over 25% over the long period.

The temperatures are rising

No less important are the effects of rising temperatures. "The share of evapotranspiration reached 59.4 per cent of precipitation, compared to the long-term annual average of about 52 per cent," it further emerges. "This was caused by the high temperatures, which are higher than the climatological reference averages, which also occurred in 2023.

The research also records the 'negative trend in the availability of renewable water resources'. "At around 373 millimetres, corresponding to 112.4 billion cubic metres on the national territory, the availability of water resources, although recovering compared to the historical minimum of 2022 (almost a +68%)," the study continues, "has nevertheless recorded a reduction at the national level of 18.4% compared to the annual average of the long period 1951-2023 and almost 16% compared to the 30-year climatological period 1991-2020".

All this is the result of a combination of a lack of rainfall in February, March, September and December, and an 'increase in water volumes of evaporation from ponds and soil and evapotranspiration from vegetation'.

From the Alps to Sicily

As for the availability of water resources, in 2023 the highest figure was recorded in the Eastern Alps, with a value of approximately 664 millimetres (a little more than 23 billion cubic metres), which constitutes 51.2 per cent of the annual precipitation and corresponds to approximately five times the availability of resources in the District of Sicily for the same year.

In 2023, Friuli Venezia Giulia is the region "with the highest total annual precipitation (more than 1750 millimetres), just as Sicily is the region with the lowest (565.5 millimetres). In terms of natural availability of water resources, however, it is Puglia the Region with the lowest with 100 mm in 2023 (almost half of the long-term average value)".

Centre South in crisis

In the last three months of the year, which are generally the wettest, particularly in Sicily and parts of Ionian Calabria, there was a significant rainfall deficit.

"This deficit led to a situation of extreme drought with effects in terms of water severity that," the study highlights, "continued into 2024, affecting central and southern Italy and the major islands, and worsening further due to low rainfall later in the year.