Protection of settlements from floods and debris flow on the example of tragedy in Tbilisi on 13-14 June of 2015

This article presents material about the flood on the Vere River on 13-14 June, 2015. It caused significant economic and ecological damage to the country, and there were also human victims. The reasons for the ecological disaster are evaluated and appropriate hydrological calculations have been carried out. It has been particularly established that the predictable (forecasting) maximal discharges of 0,1% value for Vere River is 520 m3/sec and not 410 m3/sec, that was calculated water conduct tunnels in the entrance of city before the Mtkvari River. The flood on the 13-14 June 2015 and the connected tragedy was caused by high intensive precipitation in the catchment basin, the activation of geodynamic processes, and also anthropogenic factors. In our opinion, a reason of disaster also was a design flaw in hydrotechnical buildings (tunnels) – they are not able to manage a water flow rate of 0,1% assurance. The paper presents the recommendations necessary for us to avoid, or at least reduce, the ecological and economic problems caused by floods and debris flow. The presented recommendations against a disaster like that which affected Tbilisi, as well as the expected environmental problems on territory with similar natural conditions, will enable us to avoid or reduce damage caused by flood and debris flow

Estimation of breaking risks of Zhinvali Earth Dam taking into consideration the “CAPRA”

Г. В. Гавардашвили, Э. Г. Кухалашвили, Т. Г. Супаташвили, И. Р. Иремашвили, И. А. Купарашвили, К. Г. Бзиава, Г. Т. Натрошвили. ОЦЕНКА РИСКОВ ПРОРЫВА ЖИНВАЛИЙСКОЙ ПЛОТИНЫ С УЧЕТОМ МЕТОДА «CAPRA»Georgia is one of the most vulnerable countries to natural disasters within South Caucasus Region. In recent years, the disaster risk has increased due to faulty land-using. Outstanding building codes lead to inadequate building construction. There is a lack of real data on natural disasters and the impact of mudflows, floods, debris flows etc. on land-use planning and prompt actions after above mentioned catastrophes. Therefore, it is important task to carry out assessments of critical structures sensitive to natural threats such as dams and reservoirs. In order to be able to improve the resistance of hydraulic engineering structures it is necessary to utilize a formal risk analysis framework, such as the Critical Asset and Portfolio Risk Analysis (CAPRA) method. The scientific article examined the creation of a framework for the condition of the earth dam and risk management using the analysis of the critical state and the risk portfolio, which was developed by Professor Billal Ayyub who represents Maryland University in USA, to examine human-caused threats, such as terrorism events, and natural hazards, such as flooding due to dam failures, with focus on potential failure modes due to deterioration. For this purpose, based on the field and theoretical studies, the regulation of hydrological (floods, debrisflows, snow avalanches), geological (erosion, mudflows), and seismic (earthquake), as well as those natural disasters formed in the water area of Zhinvali Reservoir, which determines the stability and reliability of the Zhinvali Earth Dam, is estimated using existing statistical data and theory of reliability and risk. Special attention is paid to the safety of the population living in the risk zone, as well as the development and evaluation of methods and principles of the impact of expected disasters

Geographic variation in the field response of male European pine sawflies, Neodiprion sertifer , to different pheromone stereoisomers and esters

The European pine sawfly, Neodiprion sertifer (Geoffroy) (Hymenoptera: Diprionidae), is a widespread and economically important forest insect. The sex pheromone communication system of this species has been previously investigated in North America, Japan and Europe, with the acetate or propionate of the alcohol (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol) shown to be the main pheromone component. In some locations, male attraction either increased or decreased by the addition of the (2S,3R,7R)-diprionyl acetate isomer. However, these studies were made with different batches of synthetic pheromones, with different types of traps and according to different procedures, so the observed differences might not reflect true geographic variation. Here we investigate the geographic pattern of male sawfly response by using identical chemicals, traps and experimental procedures at eight field sites ranging from Japan in the east to Canada in the west. We found an increased inhibitory effect of the (2S,3R,7R)-isomer from Japan and Siberia to Europe. At the eastern sites, increasing amounts of the (2S,3R,7R)-isomer up to and equal to the amount of the (2S,3S,7S )-isomer, did not influence the trap catch, whereas at sites in Europe, as little as 1% of the (2S,3R,7R)-isomer almost completely inhibited the attraction. The response of the North American population was intermediate. The only site in which the (2S,3R,7R)-isomer was essential for the attraction of males was in Siberia. A similar pattern was found for the (2S,3R,7S)-isomer. Both the acetate and the propionate form of the (2S,3S,7S)-isomer were attractive by themselves in Japan, Europe and North America, and neither the (2S,3R,7S)-isomer nor the (2S,3R,7R)-isomer alone were attractive, in the acetate or propionate form. We discuss the significance of our findings for the development of more efficient monitoring schemes and for the causes of population divergence and speciation in the European pine sawfly