Lake Garda is overflowing, level even too high: +138 centimetres on the threshold

24 May 2024

RIVA DEL GARDA. Last year there was a drought and the lake was very low, this year there is plenty of rain and the basin is overflowing. Since 16 May, Lake Garda has been higher than the guard height set at +135 centimetres above the hydrometric zero of Peschiera (i.e. the level at which the lake water begins to flow into the emissary, the river Mincio) and is now around +138 cm.


The height of the lake surface is artificially regulated by the Salionze locks on the Mincio managed by the Aipo (Interregional Agency for the Po River). The inflow of water into the basin therefore depends on rainfall, while the outflow volume depends on human decisions. Yesterday, 150 cubic metres per second were flowing out and 170.7 cubic metres were coming in (data from www.laghi.net).


Gaetano La Montagna, manager of Aipo East Lombardy, is responsible: 'We are deriving (letting out from the lake ed.) 150 cubic metres per second, more than this we cannot do, there is the risk of creating some problems downstream. The rainy season seems to be winding down, so we need to be patient'.


In 2022 and the winter of 2022-2023 there was a drought in northern Italy. The level of Lake Garda was at an all-time low, on 19 April 2023 it was +46 centimetres above the hydrometric zero. Its waters are used in spring and summer to irrigate the Mantuan countryside: if it had not rained in spring 2023 the situation for farmers would have become thorny. The winter that has just ended and the current spring, on the other hand, are prodigious with rain.


'We were a bit unlucky,' says La Montagna, 'because the weather events on the Po Valley have been exceptional; last week the weather event had 300 years of return time, which is really significant. On Lake Garda there were a few localised problems such as at the Lazise lakefront, which is a bit low, there clearly with the lake at almost 140 cm and the lakefront at 130, the water is higher than the promenade. There have also been some problems with the overflow of the disposal system, but these are local problems. Nothing to do with the safety of citizens or town centres. We will obviously maintain the 150 cubic metres per second for quite a few days also because we need, from Monday onwards, to progressively lower the lake because we have to do the Pnrr works'.


Next week, therefore, the construction site will open at the Salionze dam, the weir built on the Mincio outflow in the 1960s, six kilometres south of Peschiera, to artificially regulate the flow of Garda waters and, therefore, the level of the lake.
"It is the modernisation of all the regulation systems on the Mincio," La Montagna explains, "from the Salionze dam to Governolo, we will replace all the sluice gates with a 20 million Pnrr funding. On Monday, work will begin on a major seismic adjustment to the dam. The goal is to have a better performing system. Also because since it was built sixty years ago, such a major intervention on the entire structure has never been done. We need to arrive in September October with the lake at 70 centimetres in order to then face the autumn".
In close contact with Aipo is the Garda Community, in particular through its secretary Pierlucio Ceresa: 'We have had exceptional weather events. The level of the lake,' he said, 'is very high, we are struggling to get it down. The lake is stationary at around 138 centimetres'.
Asked whether the Garda has been kept at an excessive level in recent months, Ceresa replied: "We have had a season that could have been droughty. A year ago the problems were the opposite, so we had to keep the lake in certain conditions. For the past month, I have been in contact with Aipo to urge and ensure that it does not rise any higher. The maximum limit is at 135 centimetres above the hydrometric zero and we are now at 138, but it is dropping slightly. The maximum is coming out, the discharge is at 150 cubic metres per second, more than that you can't because you have to take into account the hydraulic tightness of the Mincio municipalities, downstream, and the Mantua lakes'.



Read the full article on: https://www.ladige.it/territori/riva-arco/2024/05/25/il-lago-di-garda-e-pienissimo-livello-anche-troppo-alto-138-centimetri-sulla-soglia-1.3793336