Icings in the project area of the Power of Siberia–2 gas pipeline in the Republic of Buryatia

The objective of this study is to evaluate the extent of icings formation along the proposed gas pipeline route within the Republic of Buryatia, including the identification of the areas of their formation, genesis, spatial and temporal dynamics, and potential negative impact on engineering structures. The study was conducted using remote sensing (RS) methods. Based on data from Landsat 4-5 and Landsat 8 satellites, normalized difference snow and ice index (NDSI) maps were created to illustrate the progression of the icings along the gas pipeline route between 1990 and 2022. The approach employed enabled the most reliable determination of the icing’s location areas, which would otherwise be unfeasible using images from a single year and challenging to ascertain in the field for the southern geocryological zone. It was determined that over 30 icings formations, encompassing a total area of 3.7 km², have been observed along the gas pipeline route during the cold season. The formation of the majority of these icings is linked to groundwater emerging at the surface due to cryogenic pressure during the seasonal freezing of rocks (groundwater icings). Over half of the icings are formed annually in the same locations, with seven of them situated along tectonic faults. This may indicate that they are fed by groundwater from deep underpermafrost water-bearing aquifer complexes, which is released through hydrogeogenic taliks. Upon designing gas pipelines, it is essential to consider the probability of icing formation along the route, not only in the northern areas but also in the southern geocryological zone. In this zone, both the construction of facilities and auxiliary structures and their subsequent operation may result in the activation of icings formation processes due to changes in permafrost and hydrogeological conditions.