Danger zone plan for torrent and avalanche control

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The danger zone plan of the forest technology service for torrent and avalanche control  ( GZP ) is the recording of torrent and avalanche risks of torrent and avalanche control  (WLV) in Austria. It is based on the creation of hazard maps and hazard zone plans .

Legal basis

The legal basis for danger zone  planning at the federal level is the Forest Act (ForstG), in which section II (forest spatial planning) basically regulates danger zone planning. The current Federal Ministry of Agriculture, Regions and Tourism (BMLRT) is commissioned to carry this out, which is to use the bodies of the torrent and avalanche control agencies (Section 11, Paragraph 1). In § 8 the danger zone plan is defined as a forest spatial plan , in § 11 the procedural sequence of the creation as well as the participation of the municipalities and the population. More detailed provisions on content, form and design are contained in the Hazardous Zone Plan Ordinance. Above all, it specifies the spatial units for which danger zone plans are to be created and the content of the cartographic and textual parts. Hazard zone plans therefore provide the basis for

(1) the planning and implementation of WLV measures as well as the ranking of these measures according to their urgency and
(2) for planning in the area of ​​spatial planning, construction and security


The general aim of the danger zone planning is therefore the representation of areas that are endangered by torrents and avalanches, the degree of danger and the areas to be reserved for protective measures.

At the state level , legal bases for hazard zone planning can be found in various state laws of all federal states with the exception of Vienna. The danger zone plan usually refers to a municipality. Deviating from this, danger zone plans can also be drawn up for sub-areas of a municipality if this appears expedient due to the size of the area, or if the WLV requires a danger zone plan as a basis for planning construction measures. The maps contained in the danger zone plan are partly, like the danger map, for the entire planning area and partly, like the danger zone map, only for the spatially relevant area , i.e. in particular the settlement area on watercourses and areas and the catchment areas concerned . created. A preliminary examination of the danger zone plans by the BMLFUW is intended to ensure the comparability of the draft plans in the approval process.


The torrent and avalanche cadastre  (WLK), the complete directory of all avalanche stretches and catchment areas and all wild waters in Austria including protective structures, the central business area of ​​the WLV, has existed since its foundation in 1884. The implementation of this directory with regard to risk assessment was created especially after 1975.

Hazard map

The hazard map gives an overview of the entire planning area and shows all catchment areas of torrents and avalanches that can affect the area relevant to the area, with names and numbers . If attention is drawn to the respective causes of danger within the catchment areas, specified plan symbols must be used . These are signatures for mass movements with which on the one hand geomorphological phenomena (e.g. sliding areas) and on the other hand processes (e.g. falling processes) are represented. The hazard map is created on a scale of 1: 50,000 or 1: 25,000.

Hazard zone plan

The danger zone plan is an extensive report with "Presentation and assessment of natural hazards in accordance with the applicable legal situation, in particular the Forest Act 1975, as  amended ". It contains the area within the area relevant for the determination of the area. Red and yellow danger zones as well as reserved and information areas are shown over a large area . Within the designated danger zones, the different types of danger are represented by letter combinations and marked in color. The zoning is specified in the Hazardous Zone Plan Ordinance, whereby, if available, hazard zones shown in red and yellow and blue reserved areas must always be identified, while the delimitation of brown and purple warning areas is optional. The demarcation of the zones is based on purely technical criteria, regardless of the parcel boundaries.

  • The red danger zone includes those areas that are so endangered by torrents or avalanches that their permanent use for settlement and transport purposes is not possible or only possible with disproportionately high effort due to the likely damage effects of the assessment event or the frequency of the hazard.
  • The yellow zone encloses areas whose permanent use for settlement or traffic purposes is impaired as a result of this hazard.
  • Those areas are mapped as blue reservation areas that
  • : (1) are required for the implementation of technical or forestry-biological measures by WLV departments and for the maintenance of the functions of these measures or
  • : (2) require a special type of management to ensure a protective function or a successful construction.
  • Brown warning areas indicate areas which, due to elevations, are likely to be exposed to natural hazards other than those caused by torrents and avalanches, such as falling rocks or landslides not related to torrents or avalanches .
  • Purple warning areas are areas whose protective function depends on the preservation of the condition of the ground or terrain.

The basis for the designation of the red and yellow danger zone is the assessment event , which corresponds approximately to a 150-year recurrence probability. The danger zones represent an expert determination of the sum line of all possibilities in the event of a measurement event and can be assessed as qualified expert reports with a prognostic character.

Text part

The text part supplements and explains the map part of the danger zone plan and thus ensures the traceability of the statements on the maps . Accordingly, a description of the planning principles used, a justification for the assessment and representation of the danger zones as well as notes for spatial planning, construction and security are included. For the planning bases used, all documents are listed in the form of maps, aerial photos, literature references and reports that are available for the respective planning area and that were incorporated into the creation of the hazard zone plan. This also includes a compilation of all catchment areas of torrents and avalanches that affect the spatially relevant area, as well as relevant catchment area parameters such as area, runoff and the potential bed load during a measurement event.

The description is standardized for each catchment area using appropriate forms. In addition, inspection protocols are integrated in the text section, which are prepared for each catchment area. This summarizes all the observations that are important for the assessment of the individual torrents and avalanches, such as conspicuous herds of bed load or possible eruption points of a channel . A description and justification of the representation of the danger zones and reserved areas as well as notes for spatial planning, construction and security supplement the text part. Suggestions are made here as to how the statements of the danger zone plan should be incorporated into the processes of local spatial planning . In addition, possible construction requirements for the yellow zone are formulated.

Legal relevance

The consideration of the danger zone plans by private individuals and municipalities cannot be legally enforced. For this reason, the forerunner of today's BMLFUW created the set of obstacles , according to which non-observance of the danger zone plans can prevent the allocation of state funding for protective measures against torrent and avalanche risks, which in itself represent a voluntary service by the federal government. However, the respective state governments can also issue special building regulations on the basis of the reports. In Lower Austria, for example, building in the red zone is prohibited and areas where the hazard potential cannot be eliminated must be rededicated.

Creation process

After receipt of the order for a danger zone plan for a municipality by the responsible section management of the WLV, the respective plan author, in consultation with the mayor, first determines the area-relevant area for which the danger zone plan is created. During the subsequent creation of the hazard map, an overview of the hazard situation is given with the help of aerial photo evaluations and other basic data as well as the event register. This backward-looking indication is updated through a current overview as part of a systematic inspection of the individual catchment areas.

Taking into account all available sources and the findings from the site inspection, a draft of the danger zone plan is drawn up. The delimitation of the individual danger zones is carried out by determining the areas of impact of processes in the room on the basis of the measurement events of a defined annual rate . For this purpose, analogies to potential events in similar topographical situations are made primarily on the basis of events of a known extent in the past - and usually also calculations and process modeling. All work steps are based on the current state of scientific knowledge. Tried and tested methodological developments are incorporated into the practice of hazard zone planning.

The approval procedure following the completion of the draft hazard zone plan results from Section 11 of the Forest Act. As a result, the draft of the danger zone plan is to be sent to the responsible mayor and then to be displayed in the community for four weeks for general inspection. The launch is to be announced publicly. Anyone who can substantiate a legitimate interest is entitled to comment in writing on the draft of the danger zone plan within the opening period.

Then the draft of the danger zone plan is to be checked by a commission for its technical correctness and, if this appears necessary, to be changed. The commission consists of a representative of the Federal Minister for Agriculture, Regions and Tourism as chairman as well as one representative each from the responsible office of the WLV, the state and the municipality. Since this review by a committee represents the last technical stage in the preparation and approval process, it plays a key role in the preparation of the hazard zone plan. The technical decision of the commission corresponds to the final determination of the zoning. The Federal Minister has to approve the draft of the danger zone plan examined by the commission; the responsible offices of the WLV have to make the approved danger zone plan available for inspection and copying. One equivalent each is to be made available to the local authorities and district administrative authorities concerned . All test and approval steps are contained in the form of detailed records in the text part of the hazard zone plan.

This standardized procedure for the official designation of danger zones has been practiced successfully for over 30 years and has undoubtedly led to the alpine habitat in Austria having a high safety standard.


Since the 2000s, the danger zone plan has also been digitized and implemented as a geographic information system and web GIS , and networked with other geographic information data.


The danger zone plan is available to every municipality , the district administration and the regional construction management for torrent and avalanche control .

The entire plan is also available online for citizens via the environmental hazard service HORA (hora.gv.at) of the Ministry of Life, where it is integrated into the flood risk zoning Austria  (HORA). The map is also partially available on the GIS servers of the countries (portal: Geoland ).


  • Federal Ministry of Agriculture and Forestry, Environment and Water Management - Department IV 5, Torrent and Avalanche Control (Ed.): The danger zone plan of the forestry service for torrent and avalanche control . Folder ( pdf , Lebensministerium.at)
  • Helmut Aigner: The danger zone plan for torrent and avalanche control ., Lower Austria GEOTAGE - 29 & 30 September 2011 in Haindorf near Langenlois. In: Reports Geol. B.-A. 88, pp. 19–23 ( pdf , www.geologie.ac.at)
  • Nikolaus Gstir (Telekom Austria AG - EID / Central Services Risk Management), Franz Schmid (WLV): The model of danger zone planning in spatial development - real or unreal? In: 10th International Conference on Information & Communication Technologies (ICT) in Urban Planning and Spatial Development and Impacts of ICT on Physical Space , 2005, conference report, pp. 437–441 ( pdf , corp.at - conference website)

Web links

Individual evidence

  1. 30 years of danger zone plan for torrent and avalanche control. For the anniversary event 30 years of the danger zone plan 2005. (No longer available online.) In: Rinderzucht Austria. Central Association of Austrian Cattle Breeders (ZAR), October 7, 2005, formerly in the original ; Retrieved on May 1, 2012 (given web link is now invalid).  ( Page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Toter Link / www.zar.at  
  2. Quoting the danger zone plan. bmlfuw.gv.at → Forest → Austria's Forest → Spatial Planning (accessed April 19, 2016).
  3. Seven percent of the buildings in the red zone . ORF, August 11, 2012 (accessed on August 11, 2012).
  4. ^ State of Salzburg, Section 7: Spatial Planning; Ref. 7/01: Landesplanung und SAGIS, Friedrich Mair (Ed.): Descriptive data interface for the digital recording of hazard zone plans in the state of Salzburg , Salzburg, February 2005 ( pdf ( memento of the original from April 20, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Service.salzburg.gv.at) @1@ 2Template: Webachiv / IABot / service.salzburg.gv.at
  5. Danger zone plan, agrar.steiermark.at