Storms are causing concern in Italy. Recently, Verona is threatened with flooding. But a tunnel to Lake Garda helps. Not without consequences for the North Italian Lake.
Riva del Garda - Storms keep hitting Italy. Recently, Tuscany struggled with significant flooding. In an Italian seaside resort not far from Rome, a tornado caused damage and a storm surge on the beaches. And another example: in mid-August, a landslide and mudslide swept through the Italian mountain community of Bardonecchia in northern Piedmont.
Etsch-Lake Garda Tunnel: To protect against flooding in the Italian Veneto
Forest fires due to heat or debris flows due to heavy rain – Lake Garda is not spared from the extreme weather either. Nevertheless, the huge Northern Italian Lake is considered a large water reservoir. For this reason, the Italians completed the so-called “Etsch-Lake Garda Tunnel” in 1959. The idea behind it: Lake Garda should serve as a reservoir when the Etsch river has too much water.
That's exactly what happened at the end of October. As the news portal
Südtirol News
reports, the northern Italian city of Verona with its around 260,000 inhabitants (Veneto region) was threatened with flooding at the time. That's why the authorities activated the tunnel, which is hardly known in Germany, to drain water into Lake Garda. So that the water does not overflow the banks of the Etsch, which also flows through Verona.
At that time, the Etsch was swollen significantly after persistent rain in Trentino and South Tyrol. At 415 kilometers long, it is the second longest river in Italy. The Etsch rises in the South Tyrolean mountains, flows through the Adige Valley (Italian: Valle dell'Adige) and the Northern Italian Plain in Northern Italy. Finally it flows into the Adriatic Sea south of Laguna Veneta.
Etsch-Lake Garda Tunnel: Trentino authorities divert floodwaters through Monte Baldo
On October 31, the authorities in Trentino decided to put the Etsch-Lake Garda tunnel back into operation. This was last the case on October 29, 2018 (see tweet below), writes the
Südtirol News
. The entrance to the tunnel is at the village of Mori, which is located directly on the busy Brenner motorway. The Etsch runs parallel to the Brennero, as the well-known holiday route in Italy is called.
Over a length of ten kilometers, the water flows through the tunnel under the Monte Baldo mountain into the northern basin of Lake Garda. With an area of 370 square kilometers and a volume of 49.3 cubic kilometers, this is the largest lake in the Mediterranean country.
Etsch-Lake Garda Tunnel: Water outlet is located at Riva del Garda
The tunnel's outlet is approximately one kilometer south of Torbole on the north bank. The tunnel ends not far from the small town of Riva del Garda, which is the destination of many holidaymakers from Bavaria and Baden-Württemberg.
The authorities only open the tunnel if there is an extraordinary risk of flooding. Because: The procedure is indeed effective. But: It also poses ecological risks for Lake Garda. After all, the water of the Etsch is significantly colder. According to the website of the autonomous province of Bolzano, the Etsch in South Tyrol is only five to seven degrees in places.
Etsch-Lake Garda Tunnel |
|
|---|---|
Start of building: |
March 1, 1939 |
completed: |
May 18, 1959 |
Inlet: |
at Mori |
Outlet: |
near Torbole into Lake Garda |
Length: |
9873 meters |
average diameter: |
eight meters |
From the Italian Etsch: Cold water flows into Lake Garda in the north
The annual average temperature of Lake Garda water, however, is 15 degrees. In summer the water can heat up to 20 degrees. And the fish that are native to Lake Garda have gotten used to it. In general, if the water temperature falls below the optimal range, this can lead to stress, damage or even death for fish, writes the fishing magazine
Fisch & Fang
.
In addition, the water released into Lake Garda contains sediment. So small rock residues from the Etsch riverbed and from the mountains through which it flows. This explains the dark, brown color of the water that reaches Lake Garda near Torbole. That's not good for the lake either: According to a study by the “Lower Austrian State Fisheries Association”, increased suspended matter concentrations mean natural stressful situations for fish for a short time.
(pm)