Austria is a very water-rich and mountainous country. Its share in the East Alps accounts for almost two thirds of the national territory. Also extra-Alpine regions such as the Mühlviertel or the Waldviertel are located at higher altitudes and are mountainous. Due to its geographical situation only 38 percent of Austria’s territory are suited as permanent settlement area. In alpine provinces this share is much lower.
River valleys and basins have therefore always been the essential areas where settlements developed. ‘Hydraulic engineering’ has a long tradition in Austria. Already t a very early time in history protective structures were built already to reduce the risk of floods for humans. Nevertheless we have to admit: There is no 100% protection against flooding. Certain risks will always remain.
Responsibilities of the Federal Water Engineering Administration
It is therefore one of the key tasks of the Federal Water Engineering Administration not to respond to flood events on a short-term basis, but to develop a future-oriented strategy and planning. In addition to active flood control through measures like river regulations, dikes and retention basins, passive flood control is gaining increasingly in significance. This includes for example keeping flood discharge and retention areas clear. The protection of water bodies and the protection against water bodies have to be integrated and implemented harmoniously in a modern protective hydraulic engineering system.
In spite of the public sector’s responsibility for flood control measures, also each individual person is responsible for making provisions for his/her own protection at an acceptable level.
Personal responsibility starts already when purchasing a specific piece of land.
Already before you plan to buy a piece of land information on potential hazards should be obtained from the municipal authorities or the official services responsible for water engineering. That’s the only way to avoid purchasing a permanent flood risk or potential damage for the mere sake of a favourable price or a beautiful location.
Hazard zone maps and maps of flood discharge areas comprise information on potential hazards. They are available for inspection at the municipal offices, the district administration authorities, the offices of the provincial governments, as well as at the regional headquarters of the Forest Engineering Service in Torrent and Avalanche Control.
With non-binding consultation and guidance, experts from the Federal Water Engineering Authority and the Torrent and Avalanche Control Service offer valuable support in such decisions.
Private precautions in building and rehabilitating
When planning new buildings or rehabilitating existing ones it is indispensable to take into account information on potential risks of flooding or high groundwater levels. Construction methods and materials which are adapted to the situation and the degree of hazard help to reduce potential damage and related costs. Such measures are for example: Doing without cellars in areas with high groundwater levels and designing building apertures appropriately.
Information on locally applied measures and on suitable ways of construction and materials can be obtained from the municipal and provincial building authorities.
Residual flood risk
Perfect flood protection does not exist. Thus, according to the relevant guidelines, flood protection for residential areas and other high-value-added areas is tailored to a flood event (statistically) occurring every 100 years. This is an event which statistically occurs on average once in hundred years. However, this does not mean that 100-years events cannot occur more frequently or cannot be exceeded in terms of their runoff levels.
In the case of floods exceeding the flood levels used as the calculation basis for flood control installations we have to reckon with inundations also in protected areas, “behind the dike”.
Engineering strategies to minimise flood damage
Flood and high levels of groundwater cause damage on buildings and outside structures due to the flow of water, the pressure exerted by the water, by water entering the building, as well as by debris and mud flow.
At the building itself or on the piece of land various measures can be taken to protect against damage caused by flood or high-standing groundwater:
- Water-proof and buoyancy-proof basement- tanking foundation solutions for new buildings
- Prevent water backup from sewage system
- Water barriers at the plot boundaries, sand bag barriers
- Water-proof closings for windows and doors
- Use building materials for walls and ceilings which are water-proof or water insensitive and which have as little hollow space as possible
- Transfer heating facilities, current distribution boards and precious furniture to the upper floors
- Do not use oil heating or fix oil tank against uplift (risk that oil escapes)
Other preventive and protection measures
Each household can develop its individual emergency provisions and its own, individual alarm plan:
- Keep sand bags, mobile closing components and other equipment available for use, maintain pumps at regular intervals, store supplies
- Define rules of conduct and distribution of tasks for emergencies and communicate them (neighbours, children, etc.)
- Conclude a building insurance against floods
- Observe flood warnings by emergency response organisations, municipalities or provincial services
The best thing you can do is to keep away from areas at risk.