GEO-INFORMATION ANALYSIS OF MUDFLOW DANGER AND THREAT ASSESSMENT FOR BRIDGE STRUCTURES WITHIN THE TERRITORY OF TRANSCARPATHIA

Abstract

Problem Statement and Purpose. Mudflows are quite common in the world and in Ukraine in particular. There are three mudflow-prone basins in the Carpathian region of Ukraine. Mudflowing processes threaten infrastructure facilities, in particular highways and bridge crossings. Therefore, it is advisable to monitor and forecast their development. Geoinformation technologies are the main tool that should be used for monitoring and modeling the development of mudflow processes. Damage to bridges, which are primarily exposed to the mudflow process, as a result of mudflows, is caused by phenomena that can be summarized by the terms – impact, abrasion, erosion and vibration. Mudflows also activate erosion phenomena, change the position of the watercourse channel, which leads to damage to bridge structures. The purpose of the study is to assess the risk of mudflows for bridge structures for the territory of eastern Transcarpathia using methods of geoinformation analysis and modeling. Data & Methods. At the present stage, it is common to model and forecast the development of mudflow processes based on taking into account the combined effect of factors. The main factors of the occurrence and development of mudflow phenomena include: tectonic, geological, hydrological conditions, modern exogenous geological processes, soil and plant cover and anthropogenic activity. The process of modeling and forecasting of mudflow hazard includes such basic stages as the selection of a set of factors affecting the development of mudflow, assessment of the level of their influence, calculation of integral indices of sediment activity, creation of a prognostic geo-informational model of mudflow hazard. Results. A spatial prognostic model of mudflow hazard was created for the area that occupies the eastern part of Transcarpathia, the main part of which is located in the mountainous Carpathians. Mudflow processes of rain genesis are mainly observed in the mentioned territories. The spatial model has a constant character, since the spatial factors of the development of mudflow processes are not variable in time and determine the probability of the occurrence of a mudflow phenomenon in space, the period of activation is determined by the influence of time factors for which a time complex indicator should be calculated. Based on the created mudflow hazard model for the research area, the mudflow hazard for bridge crossings was assessed. It was established that a high probability of mudflow hazard is characteristic of 45 bridges. These bridge structures are located in the upper reaches of the Tereblya and Teresva rivers, in the basin of the Black Tysa and White Tysa rivers. For a detailed assessment of engineering and geological threats to bridge structures as a result of the development of mudflows, floods, coastal erosion processes, it is advisable to use a comprehensive approach, using the toolkit of geoinformation systems and a wide range of data sources, in particular, data from remote sensing of the Earth.