The Avalanche Geodatabase Development and Hazard Mapping for the Bishkek-Osh Road in Kyrgyzstan

Abstract

About 53 % (105 000 km²) of the territory of the Kyrgyz Republic are subject to avalanche activity. It is estimated that there are about 30 000 avalanche release areas, from which about 1 000 (3 %) pose a serious threat to people. However, due to new developments in the mountains (e.g. new roads) it is likely that the risk will increase in the next years. The main objective of this research was development of the digital avalanche geodatabase with hazard mapping and modelling of the afforestation susceptibility along the M41 Bishkek-Osh Road. It is the main road between the two largest cities of the Kyrgyz Republic, Bishkek and Osh. The highway crosses the Kyrgyz Range, the Talas Range and the Fergana Range of the Tian Shan Mountains and passes through regions with hot or warm summers, with cool summers and cold winters, through cold steppe and, in the high altitudes, through tundra climates. Various natural hazards endanger the mountainous sections of the highway including the avalanche hazard. The road section from the Ala-Bel Pass to Toktogul Town is selected for the identification and detailed analysis of the avalanche prone areas with the highest potential for reforestation and afforestation. This study included the delineation of the exact release areas as polygon based on an analysis of the inclination, surface roughness and flow accumulation. The release areas are linked to the avalanche catchments in the avalanche cadastre and can in future be used to simulate the runout distance and the destructive potential of design avalanches. The further modelling and mapping of the basic avalanche initiation susceptibility resulted in a map of potential avalanche release areas and the release susceptibility. The GIS based avalanche cadaster only contains large avalanche catchments, which pose a known and considerable risk to the road and mainly originate from avalanche release areas situated above the current mean or upper timberline. This study is part of the project “Natural Hazard Risk Management for Transport Infrastructure in Kyrgyzstan: Focus Avalanche Protection Forests” funded by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW).