During recovery, the reconstruction of buildings and infrastructure are top priority – as well as the analysis of the disaster. After having dealt with the most urgent problems, every day life returns successively. The main duty is to correctly convert the results of the disaster-analysis and to integrate them into planning. Sustainable solutions are to be preferred to easy or cheap solutions.
Evaluating disasters should help to understand the evolution of an event and the involved processes (e.g. rain, discharge and transport of soil and rock material or snow and ice), as well as to classify them in comparison to previous events.
It is important that first results of disaster analysis should be at disposal as soon as possible, in order to plan reconstruction and to be able to correct former mistakes or deficiencies. Caused damage on buildings, infrastructure and cultivated areas show the vulnerability. They, too, have to be analysed in detail that during reconstruction the right consequences can be taken. Evaluation includes the analysis of activities of management units and emergency services to identify possible improvements for future operations.
Cantonal services for natural hazard (mostly the Department for Forestry or Civil Engineering) record smaller events themselves. After bigger disasters, specialised agencies take over the documentation. In extraordinary cases, research institutes support those agencies, to guarantee the sound investigation of cause and effect of the disaster and to gain data for basic research.
Protection deficiencies can be spotted in two ways:
- retrospectively: assessing deficiencies by analysing damage straight after the disaster. It must be determined whether all damaged objects are really worth protecting.
- prospectively: with regard to the future: municipalities are obliged to set up hazard maps and to clearly show the endangered areas in the land-use plan. For each zone different protection aims are determined. When comparing damage potential (vulnerability) with the hazard map, it is possible to determine protection deficiencies using defined scenarios.
Actors in charge
During the process of determining protection aims and deficiencies a lot of specialists and institutions are involved, as the main aim is to protect endangered people in and outside of buildings and to protect valuable assets. Landowners have to know a possible protection deficiency as well as do insurance companies.
If people or animals are hurt or buildings and infrastructure are being destroyed during a natural event, it is necessary to find out the damage’s cause. In order to be able to do that, it is important that the various impact factors are known, such as wind speed, height of flood or the magnitude of an earthquake according to the Richter scale. Those parameters are much more difficult to determine for complex processes such as avalanches, rockfalls or landslides. Simulations and models might provide helpful results in such situations.
It is important that analysing damage already starts before clearing-up operations when the traces of processes are still visible. Even traces on only slightly damage objects within the immediate vicinity of severely damaged objects provide valuable information on the effects of natural processes, but also on the resistance of buildings.
As only very few natural hazards cause damages which can be analysed systematically, damaging processes are being simulated and investigated in laboratories, as for example the shaking table used for earthquake simulations. The results of vulnerability analysis provide crucial information for the definition of building regulations and conditions for objects in danger zones.
Actors in charge
The vulnerability analysis very often is neglected in the event of a natural event, as immediate measures and reconstruction absorb all energy. Therefore, if possible, uninvolved experts such as personnal from insurance companies and researchers should carry out the analysis.
The results of vulnerability analysis provide the basis for needed changes during reconstruction. For example the brook flume in Schlans (Surselva, GR), which was curling through the middle of the village, was replaced by a reinforced runoff channel. Due to this a couple of destroyed buildings could not be rebuilt. Simple constructive changes in reconstruction (as for example putting ground floor windows and doors a bit higher than ground level in flood areas) can effectively prevent further damage.
When, according to damage analysis and estimating the effects of further natural hazards, no or only very disproportionate reconstruction is possible, the danger zone has to be left. An example for this was the huge landslide in the housing estate "Falli Hölli" in Fribourg in 1994.
Actors in charge
In order to not make the same planning mistakes again, it is absolutely vital to pay attention to reconstructing buildings and facilities. The difference between provisional reconditions and reconstruction must be clear. Construction permits, therefore, should only be discussed after hazard and damage analysis. Authorities have to stand up to the great pressure in such situations.
Insurance companies tend to have tight building regulations for reconstruction. Landowners are asked to see their autonomy and to realise simple construction changes as for example putting entrances on a higher level or to replace a fence by a protective wall. Though it is important that future hazards are not diverted into other more unfortunate directions by "egotistical" protection measures. Therefore, it is necessary that measures are planned in a coordinated manner by authorities and experts
In case of severe damage after a natural event, the hazard assessment should be revised and the hazard zone map has to be adapted accordingly. Basing on the new hazard map, the land-use plan is to be adapted.
The land-use plan cannot be changed arbitrarily, but requires a formal revision. This usually occurs every 10 to 15 years. Urgent adaptations are put down in a so called partly revised zoning and conditions for land-use can be implemented, e.g. abolishing a recreation area or a sports field due to rockfall.
Local authorities decide on further actions and eventual part-revisions of planning principles basing on the new hazard map. These regulations are settled by the Cantons and, hence, are different all over Switzerland. Municipal and cantonal authorities work closely together in this process. The affected landowners are being involved.