Those who build and renovate plan for natural hazards
The available habitat is being used more and more intensively, even in exposed places - keyword floods. In addition, climate change is also having an impact, and damage to buildings and infrastructure is increasing. This can be mitigated, a natural hazard check helps.
Extreme events are to be expected throughout Switzerland, as shown by the recently published risk analysis of the Federal Office for Civil Protection. Heavy rain, gale-force winds, hail, etc. can lead to major damage and mean hassle and financial losses for affected businesses and homeowners. Those who deal with the issue at an early stage can save themselves a lot of trouble later on. Experts therefore advise taking preventive action with targeted building protection measures.
Location-specific hazard overview
But against which natural hazards and to what extent should a building be protected? Whether flooding from high water, debris flows, surface runoff, hail and other hazards can occur at a particular location must first be clarified. Only then can the property owner take appropriate precautions.
The Association of Cantonal Building Insurers (VKG) has revised its "Protection against Natural Hazards" platform: The most important innovation is the location query. By entering an address, interested parties receive information on all possible natural hazards at the location of the building or planned new construction. On the platform, it is now also possible to find sites without an address by searching for coordinates and plots of land. This is particularly useful for planning new buildings, according to the VKG.
The natural hazard check accesses the cantonal hazard maps and many other hazard maps. Within seconds, you get an overview of all the risks that are relevant for the location in question. In addition to the hazard levels, map views with legends, contact details for cantonal specialist agencies and direct links to the cantonal geoportals are also provided. For various cantons, specific information on legal and insurance requirements can now be accessed, according to the VKG. Over the next few months, it plans to expand the platform with additional canton-specific information.
Planning starts early
No matter whether a new building, a renovation or whether an existing building is to be better protected, the natural hazard check provides suitable recommendations. These recommendations are narrowed down using two to three simple initial questions. These questions differ depending on the user profile (owner, architect/planner or specialist). In addition to the hazard at the location, the possible courses of action are also taken into account and suitable protective measures are shown for the situation.
The scope for action in the construction phase is much smaller than during planning. At most, hail-tested products can still be selected, an automatic flood protection folding bulkhead can be installed, or a hail warning system for the slat blinds can be installed.
The earlier you plan measures for a project, the less protection will cost in the end, says risk expert Bernhard Krummenacher of Geotest AG. He is one of the fathers of Zurich Insurance's Natural Hazard Radar. This tool, which is based on official hazard maps, also provides a site-specific analysis. The expert cites two examples of effective preventive measures against flooding: "This can be a small terrain adjustment, or exposed windows are fitted with safety glass."
Be sure to contact local authority
"You have to distinguish between object and area protection when it comes to natural hazards. An example: If a certain part of a village is flooded from time to time because of a torrent, it makes little sense for each individual homeowner to protect his building. If, for example, he builds a small protective wall around his house, this would probably cause even greater damage to the neighbor's house in the event of flooding. At best, such an approach is advisable for individual, detached houses," explains Krummenacher. He therefore emphasizes: "Before implementing measures on one's own building, it is essential to contact the local authorities. Perhaps they are already planning land protection. In the case of our torrent, the municipality is responsible for site protection. The affected part of the village can therefore be effectively protected with an adapted flood protection. Thus, all properties in the corresponding perimeter are safe from flooding."
Who pays the bill?
In principle, prevention measures approved for site protection are subsidized by the federal government and the canton, Krummenacher said. Depending on the financial strength of a municipality, the contributions would be higher or lower. However, if a municipality wants to receive money for natural hazard prevention, it must prove the cost-effectiveness of a project. This is calculated using the online tool developed by the Federal Office for the Environment. "EconoMe". This makes it possible to quantify the risk to people and property. Based on the calculated risks and the costs for the planned measures, the cost-effectiveness can be determined, says the expert.
Natural Hazard Check: www.schutz-vor-naturgefahren.ch
Natural Hazards Radar: www.zurich.ch/naturgefahren
Cantonal offices (natural hazards and building protection): www.schutz-vor-naturgefahren.ch/bauherr/service/fachstellen.html
Protection target specifications of SIA 261 and 261/1
The Swiss Society of Engineers and Architects has included various natural hazards in the construction standard SIA 261/1 or revised it. It is considered an important basis for experts, because it shows how natural hazards are to be taken into account in the planning and calculation of buildings and facilities.
