Vulnerability assessment of drinking water treatment plants

In the aftermath of an earthquake it is essential that drinking Water Treatment Plant (WTP) and the relative distribution network keep their full, or at least, partial functionality. Indeed, a complete failure of such systems, associated to a long restoration time can result in serious damages to facilities and services depending on water supply as well as harmful consequences for the population. Actually, a WTP shutdown can amplify the damages caused by an earthquake in terms of economical and human losses by failing the supply of fire fighting network and consequently the extinguishment of potential fires, as well as getting worse the hygienic and sanitary conditions of population affected by the natural events, thus favouring the outbreaks of epidemics as it happened in Haiti, where cholera killed hundreds of thousands of people after the earthquake of January 12th, 2010. This paper deals with the assessment of seismic vulnerability of WTPs that constitute the first element of the water distribution network by analyzing the effects of past earthquakes on them with the aim of determining the main causes of damage (ground failure, sloshing phenomenon, structural weakness, etc...) as well as the weaker elements and then, on the base of risk analysis theory, drawing fragility curves that can be useful tools for designing reliable new WTPs and controlling the resilience of those already in service.