What is a centimetre worth? Lake Garda's level between tourism and farming

One number — centimetres above the hydrometric zero at Peschiera del Garda — tells of climate, drought, beaches and the fields of the Mincio. Five years of data, and a 2022 the lake hasn't forgotten.

By Prof. J.P. L. de Oliveira, Ph.D. • 14 August 2026 • 6 min read

People who live and work on Lake Garda watch a number almost no tourist knows: the lake level, in centimetres above or below the hydrometric zero at Peschiera del Garda. It tells them whether the beaches will be wide, whether the rental jetty will be usable, whether the ferry can dock comfortably. It looks like a weather reading. In fact it is the most political number on the lake.

Because Garda, contrary to what most assume, does not decide on its own how full it is. Its outflow, the river Mincio, leaves the lake at Peschiera and is regulated at the Salionze dam. How much water to release — and therefore how high to keep the lake — is a choice, made by balancing interests that often pull in opposite directions.

A lake decided downstream

Downstream of Salionze lies one of Italy's most productive farming areas: the Mincio plain and, beyond it, the Po. In summer those fields are thirsty, and Garda is their reservoir. That is why every year, right on cue, the level drops during the high season: it is not (only) evaporation, it is water released for irrigation. You can see it in the Salionze outflow figure we publish, updated, on the level page.

Keep the lake full for August's beaches, or draw it down for September's fields: Garda's level is the daily summary of that tug-of-war.

It is a delicate balance between tourism — which wants the lake high, the beaches presentable, the harbours working — and farming, which needs the water precisely when it rains less. In normal years the compromise holds. In dry years it breaks, and then the number becomes news.

2022, the year the lake retreated

One line in the chart breaks the pattern. In the summer of 2022, after a winter with very little Alpine snow and a dry spring, Garda fell to levels it usually never touches: from the full values of other years (often more than a metre above the zero) it collapsed to a few tens of centimetres, with autumn lows around 24-28 cm. Images of the Sirmione peninsula with its beach widened by dozens of metres went around the world.

It was an episode, but not an isolated accident: it is the shape a bigger problem takes on the lake. Less snow stored in winter means less water "battery" to release in spring; hotter, longer summers mean more demand downstream. The Garda level thus becomes a climate sensor anyone can read, no models required: just look at where the water reaches on the lakefront wall.

High or low isn't good or bad

You might conclude "high = good, low = bad". It is more complicated. A low level widens the beaches — and some bathers like that. But it makes jetties, slipways and moorings hard to use or useless, complicates ferry navigation, exposes the lakefronts in an unflattering way and stresses the shoreline's life. A level that is too high brings the opposite risk: swell, flooding of the low promenades, submerged moorings.

The "right level" does not exist in the abstract: it depends on who is looking. The sailor, the restaurateur with a lakeside terrace, the lifeguard, the farmer near Mantua and the mayor defending the promenade each have a different answer. To each of them, the centimetre is worth something different.

Why it is hard to forecast

On the level page we extend the current year with a dashed line: an estimate, not a forecast. The difference is not formal caution. The future level depends on two variables nobody fully controls: how much rain will fall and how much water will be released at Salionze. The first is weather; the second is water-resource politics, negotiated between regions, consortia and river-basin authorities. That is why our dashed line only projects the average seasonal shape of the last five years — useful for planning, unreliable as prophecy.

And that is exactly gardalytics' job: to take a number that looks technical and show that inside it live climate, farm economics, tourism and public decisions. Garda's level is not the thermometer of a tank. It is the keystone indicator of how the lake is managed — and of how much, each year, it is changing.