The level of the Garda does not give cause for concern, its temperature does.

11 September 2024

‘The current level of the lake? It doesn't give cause for concern, coming from a dry July and August, it's more than fine, and indeed, arriving in September like this’. This is the opinion of Filippo Gavazzoni, vice-president of the Garda Community and deputy mayor of Peschiera with responsibility for lake protection. 
Lake Garda stands at 92 centimetres above the hydrometric zero, equal to 69.3% of filling: a value that considers the volume of water between zero and 140 centimetres. In the last 14 days of August, the level has dropped by 12 centimetres, for a total of about 44.5 million cubic metres of water flowing from the dam (where yesterday the discharge was reduced from 65 to 60 cubic metres per second) to ensure supply to the Mantuan countryside. Certainly, some of it has also evaporated, considering the prolonged peaks of heat and the increase in surface water temperature: according to measurements taken by Arpav on bathing water, i.e. surface and near-shore water, between mid-July and early August there was a difference of about two degrees. At Torri, in a median position on the Veronese coast, the temperature went from 24.3 in mid-July to 26.4 at the beginning of August, while last year the trend was reversed: from 26.8 in July it went to 24 in August. Going back in time, Arpav's data show that the trend over the last decade for the summer period and bathing waters has seen an increase in temperatures of about 1.5 degrees. Climatic variations that add up to meteorological ones.
Last summer we were coming from a year and a half of drought, with minimum lake levels in winter replenished by spring rains. This year, on the other hand, there was a large amount of water since last winter, maintained by the spring rains until the level reached 146 centimetres at the end of June, with the need to discharge as much water as possible from the dam.
‘We don't have to think about the four centimetres less than on the same day last year, but about the trend,’ notes Gavazzoni. ‘Every year a record of warmer temperatures than the previous year is broken, much to the chagrin of climate change deniers. It is true that heat peaks have always been there, but it is the continuity of the phenomenon that worries us: this affects the evaporation index and the temperature of the water, which in perspective also changes its quality’.
The average increase in water temperatures favours the development of new species, both plant and animal, from new algae and plants to new fish and insects that, favoured by an increasingly mild temperature, find a new ideal climate in Garda 
Temperatures are also a very interesting topic for another reasoning related to the relationship between the perceived and the real. 2024 was once again the hottest year on the planet, but on Lake Garda, thanks to a rainy May (to which we owe the optimal filling level of Lake Garda) and a September that will quickly turn cool, the summer was not perceived as long and torrid as previous ones, even though there were several heat peaks. Recent reports of an almost ice-free Marmolada, less and less abundant snow (except in the last season) are news, but these elements do not affect Garda, indeed the gradual inflow of meltwater not only fills it up but also regulates its temperatures and mixing.
The scenario is destined to change, correctly forecasting the change is the only way to be ready, to do this you need clear and functional technical data, you need unity, you need planning. 


Read the in-depth article on this topic in the L'Arena newspaper of 04 September