Garda almost at maximum capacity: a water crisis April in 2023

03 April 2024

With the rains of the last week, the level of Lake Garda rose again, reaching its maximum filling level yesterday morning: 139 centimetres on the hydrometric zero at Peschiera, compared to a limit value of 140, four centimetres more than on Monday (considering the surface area of Lake Garda, each centimetre is equivalent to 3.7 million cubic metres of water).
The level then decreased slightly, settling at 137 centimetres, thanks to the return of good weather but above all to the greater opening of the Salionze dam, which was implemented starting yesterday morning. A completely different scenario compared to the same period in 2023, when at the beginning of April the Garda reached 50 centimetres on the hydrometric zero, and as the photo comparison above shows.


AiPo and Salionze
Given the high levels this year, AiPo (Interregional Agency for the Po River, the body responsible for managing the hydraulic works along the Mincio) just yesterday increased the outflow into the river to 140 cubic metres per second. "We will continue this diversion for a few days," says Gaetano La Montagna, manager of AiPo's Mantua office. "With the first of April, the irrigation season began and the Virgilio and Seriola irrigation canals are also in operation, into which we are deriving about thirty and four cubic metres per second respectively.
Most of the water released by the dam ends up in the Mincio, which in the Mantua area is divided into two branches: the artificial canal, which receives the most water, and the natural Mincio, which reaches the Mantua lakes. "In the natural Mincio we are deriving around 20 cubic metres per second," continues La Montagna, "beyond that it is not possible because a soft, i.e. spring flood, of the Po is in progress.
The great river is not at a worrying level, but the Formigosa weir (an artefact built in the Mantua locality of the same name, ed.) is closed to prevent the Po from flowing back into the Mincio and thus towards the Mantua lakes'. Pierlucio Ceresa, secretary general of the Garda Community, reassures: "The situation must be kept under control but there's no alarm, we only hope for the absence of wind and wave motion that create damage to the coastline. We are in contact with AiPo, the idea is to keep the discharge at 140 cubic metres per second until the lake reaches a level considered safe, around 125-130 centimetres, so as to reach 80-90 in June-July to ensure a good supply for the summer".


Averting the danger of drought to the detriment of agriculture
A prospect that should avert the danger of drought to the detriment of agriculture. It is impossible to calculate how much water will come from the melting snow on the mountains. "A lot of snow has already melted in the past few weeks," Ceresa recalls, "we do not have scientific data to estimate further contributions, but from the information received from the Dams Office of the Autonomous Province of Trento, the snowpack is at a high altitude and should not bring significant fluctuations.
If the largest inflow comes from the Sarca (yesterday around 100 cubic metres/sec), in the last two days the Toscolano torrent has also contributed, with 10 cubic metres per second: "This is the effect of the opening of the Valvestino dam, the artificial lake built for hydroelectric purposes that has the Toscolano as its outlet, the largest tributary of Lake Garda after the Sarca," Ceresa further informs. Contribution, the latter, which was exhausted yesterday.


Read full article: https://www.larena.it/territorio-veronese/garda-baldo/livelli-garda-confronto-2023-1.10667116