Vorarlberg water levels remain exceptionally low after dry summer

Water levels in Lake Constance and groundwater reserves in Vorarlberg remain exceptionally low after a hot, dry summer, ORF reported on Friday. The situation is particularly strained in the Walgau valley and around Bludenz, although drinking water supplies remain secure.

Lake Constance stood at 279 centimetres at Bregenz on Friday morning, two centimetres below the lowest level ever recorded there on September 4. The long-term average for the date is 385 centimetres, putting the current level more than a metre below average.

At the beginning of September last year, the lake stood at 370 centimetres. The current level is not an all-time low, however. The lowest water level ever measured at Bregenz was 231 centimetres, recorded in February 2006, when the lake generally carries less water.

The water also remains unusually warm. A temperature of 23 degrees was measured at a depth of 50 centimetres on Friday, compared with 20.9 degrees at the same measuring point in early September last year.

Groundwater especially low in the Walgau

The drought is even more evident in groundwater levels. According to the latest data from the Vorarlberg authorities, nearly all of the province’s 156 automatically transmitting measuring stations are below their long-term averages. Only one station, in Lochau, is slightly above average.

The situation is particularly striking around Bludenz and Bürs. Several stations are currently marked red on the provincial groundwater map, meaning their levels are below the lowest previously recorded at those locations. Numerous other stations in the Walgau are also reporting unusually low levels for this time of year.

Across Austria, around 32 percent less rainfall than the long-term average was recorded during what Geosphere described as the hottest summer in the country’s measurement history. Environment Minister Norbert Totschnig was quoted in a statement as saying the deficit was affecting both rivers and groundwater.

The rainfall deficit affected the entire country, especially the east, and increasingly worsened the water balance. Austria’s agriculture has suffered historic damage, according to the Federal Ministry of Agriculture, Forestry, Climate and Environmental Protection, Regions and Water Management.

At the end of August, monthly flows were below their long-term averages at more than 95 percent of water-level measuring stations across Austria. Below-average groundwater levels were particularly pronounced in parts of Salzburg, Upper Austria, Vorarlberg and Tyrol, following a winter with little snow and a dry spring.

The ministry said current forecasts from Geosphere Austria indicated that widespread rainfall was not expected in the coming days. From next week, the weather is expected to become more unsettled and wetter, with rainfall roughly in line with seasonal averages and lower evaporation. Periods of rain may occur in the second half of September, while temperatures are expected to remain above average.

Such rainfall could provide short-term relief for rivers and soils, but would not yet be enough to restore groundwater levels and river flows sustainably. Further development will depend on whether sufficiently heavy and widespread periods of rainfall occur.