The highest ever recorded discharges on Tyrolean streams, more than five-thousand-year water at the Lech, led to massive flash floods in Austria.

"People taken by surprise in the middle of the night sought refuge on roofs or tree tops, only to find themselves stranded for hours, sometime for more than 12 hours, waiting in the rain for rescuers who could only reach those places by boats or helicopters. These were the lucky ones, as others went into hypothermia from staying too long in cold waters, or found it impossible to get out of their homes being either too sick, too old, or having no one around."
Petruta Moisi, Eco Counselling Centre, Galati, Romania

The 2005 floods were driven by extreme meteorological events in parts of the Danube River Basin. In April, strong rains in the Banat area of Romania, along with melting snow in the mountain region and soil saturated by water, led to hundred-year floods in the Timis, Caras and Barzava River Basins, with the Timis flood also affecting the Serbian territory.

Two more flood waves occurred in Romania in July (in the Arges, Olt, Jiu, Siret and Prut River Basins) and August (in the Mures, Olt, Somes, Tisza and Siret River Basins). Torrential rains in a short time resulted in a huge increase in the discharge of the small rivers (or even dry valleys) and led to flash floods in the mountain area and thousand-year floods in downstream river basins.

Heavy rains also fell in Germany, in southern Bavaria and in Austria, mainly in Vorarlberg and Tyrol. Torrential rains, for example in Kochel-Einsiedl/Bayern, where the 24 hour maximum of 217 mm corresponded to a 200-year probability, along with a reduced surface retention capacity due to previous rains, led to floods in south-western Austria and in the Bavarian River Basins of Iller, Lech, Loisach and Isar. A dramatic situation arose in Tyrol, where more than two-hundred-year water was observed on the Inn in Innsbruck and more than five-thousand-year water was estimated for the Lech at Steeg, Trisanna at Galtur, and Sanna at Landeck. Massive flash floods resulted from the highest ever recorded discharges on Tyrolean streams.

Calculating the damage.
In Romania floods in spring and summer affected about 1.5 million inhabitants. Altogether 43,900 houses, 4682 bridges and footbridges, 590 social and economic buildings, 10,334 km of roads and 253 flood protection constructions were damaged or totally destroyed. More than 12,000 people were evacuated, and 71 casualties were recorded. In Serbia, the April flood in Timis flooded two villages and caused about € 14 million damage to houses and agricultural production. August floods in the upper Danube Basin also had severe economic consequences; the total cost of damages in Bavaria amounted to € 175 million, the preliminary estimate of economic losses in Austria is € 700 million.

The way out - sustainable flood risk management.
To reduce the impact of floods Romanian authorities took all possible actions to forecast dangerous situations, to consolidate flood control works (including raising the dykes along the rivers) and to evacuate residents from affected areas. But without sufficient retention capacity it was only possible to reduce the disastrous impacts of flooding.

In Bavaria, no casualties were recorded and the overall flood damage was lower than after the 1999 floods, thanks to thorough flood protection measures taken after 1999 as well as efficient reservoir management in the affected area. This was also due to the integral flood protection strategy implemented in Bavaria based on natural retention, structural measures and advanced flood prevention. Results in Bavaria show that the newly built structural measures saved the old centre of Kempten from flooding despite the 500-year discharge of the Iller. However, implementing such flood protection strategies requires substantial financial support: flood protection measures in Bavaria during 200608 would require a € 150 million annual budget.

This year's floods underlined the urgent need to apply the major principles of the ICPDR as well as the EU flood risk management policy: sufficient natural retention of water, allowing rivers ample space, environmentally friendly structural measures, integrated river basin management, efficient flood forecasting and flood warning, and a shift from defensive action against hazards to management of the risk and living with floods.

THE EUROPEAN FLOOD ALERT SYSTEM
To support efficient and timely flood forecasting and flood warning the European Flood Alert System (EFAS) is also being developed by EC JRC in Ispra for the Danube River Basin. During floods in summer 2005 the EFAS team sent external information reports to partners in Germany, Slovakia, Hungary and Austria. The historical discharges at the alpine streams on August 23, for example, were signalled by EFAS from August 20 onwards. The performance of EFAS during these events demonstrated the benefit of using a combination of deterministic and probabilistic flood forecasts.

THE GOVERNMENT'S RESPONSE
In reaction to the August floods WWF Austria asked the Austrian Minister of Environment and Water Protection to prepare a new environmentally friendly concept of sustainable flood protection since, as WWF stressed, the strategy of technical flood protection failed. A WWF study showed that in Austria an additional 840 km2 of space is necessary for rivers and creeks, which corresponds roughly to 1% of the country's territory. WWF highlighted that in 2003, while still experiencing the effects of the previous year's floods, four times as many streams were regulated as revitalised. The only solution according to WWF Austria is to give rivers more space.

We asked Heinz Stiefelmeyer, a senior flood protection expert from the Austrian Ministry of Environment and Water Protections about his position regarding the WWF statement.
He stressed that:

• The main reason for flooding in August 2002 was the excessive precipitation (extensively more than 200mm/24h).
• In Austria, only settlement areas are protected by structural measures but no agricultural plains have been protected against floods for many decades.
• Austria has an integral approach towards flood protection: only a combination of measures will lead to a reduction of damage in case of flooding. One of these measures is reclaiming of floodplains.
• Other measures include the revision of forecast-models, upgrading early warning systems, reinforcement of self prevention (self protection), securing adequate landmanagement, identifying endangered areas (Hazard/Risk maps etc).
• It is also important to note that not enough flood retention areas are available in an alpine country like Austria, especially in inner-alpine valleys that were most affected by the 2005 floods.
• Examples of extensive river expansion as well as renaturation in terms of flood protection and ecology managed by the Federal Water management administration can be found by the Lech (despite high damage) as well as by the Vils, Lafnitz, Raab, Drau, Sulm and Pielach etc.
• Additionally more than 400 acres of land have been acquired for flood plains since 2002.

Igor Liska
is the technical expert for water quality and water management at the ICPDR Secretariat
and coordinates the implementation of the ICPDR Flood Action Programme.