International Symposium on
Drylands Ecology and Human Security

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Complex Approach for the Definition of Risk-Factors
of Technogenous Systems in Flood Conditions

Guram Grigolia, Davit Kereselidze, Irakli Khomeriki

Tbilisi State University, Georgia


Humankind is well aware of flood, as one of the most frequent calamities, which causes more victims in comparison with any other extreme natural disasters. Last decades have shown significant increase of damages caused by high water and floods, which is associated with high intensity and repeated occurrence of such phenomena due to strong anthropogenic factors present at areas of water collection, river valleys and water meadows. Consequently to this, improving reliability of calculations for maximum drain, combined with risk origin studies and flood risk influence, is an actual task for South Caucasus region.
There are new technogenous systems, which have corresponding infrastructures, emerging in areas of South Caucasus, and particularly in Georgia; such systems are specified by certain risk factors. These factors, as opposed to natural factors, have features different both in terms of origin and influence. Moreover, activated are factors associated with management (control). The abovementioned factors are closely interconnected. The problem of determining priorities for risk control (definition of methods and ways for risk reduction) is being faced with. Risk estimation and risk control are two constituent aspects of the same single process of decision-making.
Safety of technogenous systems is associated with notion of danger and risk. Danger implies anticipated occurrence of any less desired and undesirable phenomenon, in the first turn the natural ones, that may cause damage to various objects. It is important not to mix up danger with risk. By making a choice of decision when designing, constructing and operating important and dangerous objects (such as oil-and gas pipelines and etc.), it is advisable to be fully aware to reduce risks for environment and human health. The higher the risk, the more reasons to perform reliably and reasonably, minimizing the risks.
The quantitative method of estimation of risk-factors in the investigated system, requires complex approach, with full coverage of all components, from hydrological one to the so-called risk control. In case of setting up large-scale technogenous systems for mountainous relief environs (e.g., same oil-and gas pipelines) the significance of calculation accuracy is increased by many times. In similar situations natural disasters of both endogenous and exogenous background may occur, namely, earthquake, floods, landslide, mudslides, change riverbeds, etc., which may pose a cause of calamity with serious negative consequences. In certain cases, each of these factors may have probability of occurrence and different rates of disaster, i.e., represent different risk-factors. In similar cases, it will be required to estimate particular criteria of safety, considering both probability of occurrence of individual calamities, and conditional probability of joint occurrence of various phenomena, as well as the risk of occurrence of each of them, by taking into account, the probability of both single and multiple exaggeration. This is a rather complicated task, and should be solved in complex with consideration of any available information and data.