An EIS for the analysis of vulnerability of water storage tanks to natural hazards

The concept of vulnerability to some natural hazards (snow, wind and earthquakes) is used in this paper to predict the level of degradation or ageing that may occur on a large scale to a water storage tank. To assess the state of these tanks, our research is based on a diagnostic method which consists in determining the index of vulnerability, taking into account all the influential parameters: environmental, structural and functional. From this index, we propose a scale of classification of tanks in three levels of behaviour (good, average, bad), and each level is associated with a different colour. Additionally, we have constructed an environment information system (EIS) - that is, a computer application associated with a geographic information system (GIS) to allow tank managers to handle the matter, and analyse, display and visualise the data well. The tanks to which we have tied the geo-referenced information are implanted as focal point objects. Therefore, the produced system constitutes for managers of storage structures a tool to reach conclusions and make decisions. In other words, the system informs us about the attention that should be given to vulnerable structures after a thematic analysis. It also allows us to better visualise the priorities of the structures that need rehabilitation. For the needs of the study, 22 tanks are investigated in Tizi-Ouzou, Algeria.