The paper presents the results of the field and laboratory research carried out in the Chokheltkhevi river basin, according to which the sediment-forming solid mass accumulated in the bed of the Chokhelthkhevi river w...The paper presents the results of the field and laboratory research carried out in the Chokheltkhevi river basin, according to which the sediment-forming solid mass accumulated in the bed of the Chokhelthkhevi river was recorded and its granulometric and chemical composition, as well as physical-mechanical characteristics, were studied. Based on the results of the research, it can be said that in the debrisflow channel of the Chokheltkhevi River, coarse and sandy-clay soils are mainly accumulated, which represent an unstable mass for the expected debrisflow in the gorge, which, together with other geological, hydrological and climatic factors, helps to increase the scale of the expected ecological danger. According to the results of the laboratory research, it can be concluded that the soil accumulated in the drainage channel is low in ion concentration, and the humus content in it is minimal, which indicates the possibility of easy displacement of the solid mass accumulated in the drainage channel and, accordingly, the risk of a catastrophic debrisflow.展开更多
Assessment and emergency planning to cope with disaster risks are usually founded primarily on expert evaluations, in part because local governments and public bodies mainly finance the recovery activities. Local comm...Assessment and emergency planning to cope with disaster risks are usually founded primarily on expert evaluations, in part because local governments and public bodies mainly finance the recovery activities. Local communities affected by disasters are scarcely really involved in the processes of information collection, problem analysis, or design of emergency plans.However, the development of good practices for incorporating local people’s knowledge into disaster risk management, known as Community-Based Disaster Risk Management (CBDRM), is becoming more common. Scientific communities increasingly realize the importance of local knowledge, though in Georgia this is still uncommon. Georgia faces frequent natural disasters and threats to its fragile ecosystems caused by unsustainable natural resource management and agricultural practices, improper infrastructure and urban development, as well as by innate geological and climatic factors. In this context, the lack of communication between local communities and public administrations is absolutely deleterious. The article analyzes the effectiveness of participatory methods and tools for better comprehension of people’s vulnerability and responses. Fieldwork in mountain areas of Caucasus involved local communities to investigate the direct participation of local people in Disaster Risk Management and assess their availability and interest to engage in hazard mapping and risk responses.展开更多
River Tergi, Aragvi and Asa-Arghuni, which occupy significant area of mountainous region of central Caucasus, by its geographic location, strategic meaning, peculiarities of natural landscape and infrastructural objec...River Tergi, Aragvi and Asa-Arghuni, which occupy significant area of mountainous region of central Caucasus, by its geographic location, strategic meaning, peculiarities of natural landscape and infrastructural objects (Trans-Caucasian highway, gas pipeline, water supply of the capital, Gudauri ski-mountainous complex) minerals, historic-ethnographic monuments, opportunities for development of mountainous tourism and mountaineering, where more important engineering projects are being planned;all the above give perspective of development of economic base, employment of the population and restoration of motivated villages, more over that the major part of their perimeter represents state border. At the same time, extremely complex relief, landscape-climatic conditions and sensitive geologic environment have been always defining peculiarities of settlement of population and agricultural activities and determining landscape-ecologic balance of geographic environment. However, whereas amount of land for optimal adaptation is extremely limited, its irregular adaptation causes critical degradation-devastation of lands. Consequently, this causes development of scaled and diverse geologic processes (land-slides, debrisflow, erosion, etc.), which have been complicated anyway and are followed by enormous material loss, forcing thousands of people to leave their homes, emptying if tens of villages and human sacrifice. The article considers conditions of development of a catastrophic debrisflow, which occurred in Dariali in the year 2014 and its negative consequences.展开更多
Debris flow often causes enormous loss to life and property,especially on alluvial fans.Engineering structures such as retention check dams are essential to reduce the damage.In hazard mitigation evaluation and planni...Debris flow often causes enormous loss to life and property,especially on alluvial fans.Engineering structures such as retention check dams are essential to reduce the damage.In hazard mitigation evaluation and planning it is of significance to determine the location,size and type of dam and the effects of damage mitigation.We present a numerical simulation method using Kanako simulator for hazard mitigation planning of debris flow disaster in Tanjutani Gully,Kyoto City,Japan.The simulations were carried out for three situations:1) the simulations of erosion,deposition,hydrograph changing and inundation when there were no mitigation measures;2) the simulations of check dams in four locations(470 m,810 m,1,210 m and 1,610 m from the upstream end) to identify the best location;3) the simulations of check dams of three types(closed,slit and grid) to analyze their effects on sediment trapping and discharge reduction.Based on the simulations,it was concluded that two closed check dams(located at 470 m and 1,610 m from the upstream end) in the channel and a drainage channel on the alluvial fan can reduce the risk on the alluvial fan to an acceptable level.展开更多
The concentration of cosmogenic loBe in riverine sediments has been widely used as a proxy for catchment-wide denudation rate （CWDR）. One of the key assumptions of this approach is that sediments originating from su...The concentration of cosmogenic loBe in riverine sediments has been widely used as a proxy for catchment-wide denudation rate （CWDR）. One of the key assumptions of this approach is that sediments originating from sub-basins with different erosional histories are well mixed. A tragic debris flow occurred in the Seti River watershed, central Nepal, on May 5, 2012. This catastrophic debris flow was triggered by slope failure on the peak of Annapurna IV and resulted in many casualties in the lower Seti Khola. However, it provided an opportunity to test the assumption of equal mixing of sediments in an understudied rapidly eroding watershed. This study documents the CWDR of ^10Be to evaluate the extent of the influence of episodic erosional processes such as debris flow on the spatio-temporal redistribution of loBe concentrations. Our data show that the debris flow caused little change in CWDR across the debris flow event. In addition to isotopic measurement, we calculated denudation rates by using the modeled concentrations in pre- and post-landslide sediments based on the local ^10Be production rate. The modeled result showed little change across the event, indicating that the debris flow in May 2012 played a minor role in sediment evacuation, despite the rapid erosion in the catchment. Our study concludes that although the 2012 event caused many casualties and severe damage, it was a low-magnitude, high frequency event.展开更多
During 13-14 June 2015 heavy rainfall in the Riv. Vere basin area and its tributaries caused a drastic increase in the water level and triggered/activated large-scale landslide and debrisflow events. This put the Tskn...During 13-14 June 2015 heavy rainfall in the Riv. Vere basin area and its tributaries caused a drastic increase in the water level and triggered/activated large-scale landslide and debrisflow events. This put the Tskneti-Samadlo and Tsnketi-Akhal- daba motorways out of order. Residential buildings and miscellaneous infrastructural facilities, buildings and structures and Tbilisi Zoo located at the low elevations in the Riv. Vere Gorge were significantly damaged or/and totally destroyed. 23 persons died during the disaster. This study presents the results on an analysis of the landslides/ debrisflows in the riv. Vere catchment and discusses main triggering factors of natural disaster, statistics for the prior period, and geodynamic situation of Akhaldaba “big” landslide developed at the Tskneti-Samadlo road section. It is given recommendations for future activities to reduce landslide/debrisflow hazard in this catchment.展开更多
文摘The paper presents the results of the field and laboratory research carried out in the Chokheltkhevi river basin, according to which the sediment-forming solid mass accumulated in the bed of the Chokhelthkhevi river was recorded and its granulometric and chemical composition, as well as physical-mechanical characteristics, were studied. Based on the results of the research, it can be said that in the debrisflow channel of the Chokheltkhevi River, coarse and sandy-clay soils are mainly accumulated, which represent an unstable mass for the expected debrisflow in the gorge, which, together with other geological, hydrological and climatic factors, helps to increase the scale of the expected ecological danger. According to the results of the laboratory research, it can be concluded that the soil accumulated in the drainage channel is low in ion concentration, and the humus content in it is minimal, which indicates the possibility of easy displacement of the solid mass accumulated in the drainage channel and, accordingly, the risk of a catastrophic debrisflow.
文摘Assessment and emergency planning to cope with disaster risks are usually founded primarily on expert evaluations, in part because local governments and public bodies mainly finance the recovery activities. Local communities affected by disasters are scarcely really involved in the processes of information collection, problem analysis, or design of emergency plans.However, the development of good practices for incorporating local people’s knowledge into disaster risk management, known as Community-Based Disaster Risk Management (CBDRM), is becoming more common. Scientific communities increasingly realize the importance of local knowledge, though in Georgia this is still uncommon. Georgia faces frequent natural disasters and threats to its fragile ecosystems caused by unsustainable natural resource management and agricultural practices, improper infrastructure and urban development, as well as by innate geological and climatic factors. In this context, the lack of communication between local communities and public administrations is absolutely deleterious. The article analyzes the effectiveness of participatory methods and tools for better comprehension of people’s vulnerability and responses. Fieldwork in mountain areas of Caucasus involved local communities to investigate the direct participation of local people in Disaster Risk Management and assess their availability and interest to engage in hazard mapping and risk responses.
文摘River Tergi, Aragvi and Asa-Arghuni, which occupy significant area of mountainous region of central Caucasus, by its geographic location, strategic meaning, peculiarities of natural landscape and infrastructural objects (Trans-Caucasian highway, gas pipeline, water supply of the capital, Gudauri ski-mountainous complex) minerals, historic-ethnographic monuments, opportunities for development of mountainous tourism and mountaineering, where more important engineering projects are being planned;all the above give perspective of development of economic base, employment of the population and restoration of motivated villages, more over that the major part of their perimeter represents state border. At the same time, extremely complex relief, landscape-climatic conditions and sensitive geologic environment have been always defining peculiarities of settlement of population and agricultural activities and determining landscape-ecologic balance of geographic environment. However, whereas amount of land for optimal adaptation is extremely limited, its irregular adaptation causes critical degradation-devastation of lands. Consequently, this causes development of scaled and diverse geologic processes (land-slides, debrisflow, erosion, etc.), which have been complicated anyway and are followed by enormous material loss, forcing thousands of people to leave their homes, emptying if tens of villages and human sacrifice. The article considers conditions of development of a catastrophic debrisflow, which occurred in Dariali in the year 2014 and its negative consequences.
基金supported by the National Science and Technology Support Program(Grant No. 2012BAC06B02)the National Natural Science Foundation (Grant No. 40971014)
文摘Debris flow often causes enormous loss to life and property,especially on alluvial fans.Engineering structures such as retention check dams are essential to reduce the damage.In hazard mitigation evaluation and planning it is of significance to determine the location,size and type of dam and the effects of damage mitigation.We present a numerical simulation method using Kanako simulator for hazard mitigation planning of debris flow disaster in Tanjutani Gully,Kyoto City,Japan.The simulations were carried out for three situations:1) the simulations of erosion,deposition,hydrograph changing and inundation when there were no mitigation measures;2) the simulations of check dams in four locations(470 m,810 m,1,210 m and 1,610 m from the upstream end) to identify the best location;3) the simulations of check dams of three types(closed,slit and grid) to analyze their effects on sediment trapping and discharge reduction.Based on the simulations,it was concluded that two closed check dams(located at 470 m and 1,610 m from the upstream end) in the channel and a drainage channel on the alluvial fan can reduce the risk on the alluvial fan to an acceptable level.
基金supported by the College of Education,Korea University Grant in 2016
文摘The concentration of cosmogenic loBe in riverine sediments has been widely used as a proxy for catchment-wide denudation rate （CWDR）. One of the key assumptions of this approach is that sediments originating from sub-basins with different erosional histories are well mixed. A tragic debris flow occurred in the Seti River watershed, central Nepal, on May 5, 2012. This catastrophic debris flow was triggered by slope failure on the peak of Annapurna IV and resulted in many casualties in the lower Seti Khola. However, it provided an opportunity to test the assumption of equal mixing of sediments in an understudied rapidly eroding watershed. This study documents the CWDR of ^10Be to evaluate the extent of the influence of episodic erosional processes such as debris flow on the spatio-temporal redistribution of loBe concentrations. Our data show that the debris flow caused little change in CWDR across the debris flow event. In addition to isotopic measurement, we calculated denudation rates by using the modeled concentrations in pre- and post-landslide sediments based on the local ^10Be production rate. The modeled result showed little change across the event, indicating that the debris flow in May 2012 played a minor role in sediment evacuation, despite the rapid erosion in the catchment. Our study concludes that although the 2012 event caused many casualties and severe damage, it was a low-magnitude, high frequency event.
文摘During 13-14 June 2015 heavy rainfall in the Riv. Vere basin area and its tributaries caused a drastic increase in the water level and triggered/activated large-scale landslide and debrisflow events. This put the Tskneti-Samadlo and Tsnketi-Akhal- daba motorways out of order. Residential buildings and miscellaneous infrastructural facilities, buildings and structures and Tbilisi Zoo located at the low elevations in the Riv. Vere Gorge were significantly damaged or/and totally destroyed. 23 persons died during the disaster. This study presents the results on an analysis of the landslides/ debrisflows in the riv. Vere catchment and discusses main triggering factors of natural disaster, statistics for the prior period, and geodynamic situation of Akhaldaba “big” landslide developed at the Tskneti-Samadlo road section. It is given recommendations for future activities to reduce landslide/debrisflow hazard in this catchment.
