ИСТИНА

Regular water and energy supply in permafrost areas are vitally important conditions for inhabitants of the large North territories of Russia. Dam and flank shore stability is the key point for safety of reservoir (power pool, water supply, tailing pit, etc.). In permafrost areas stability of many engineering structures, including hydrotechnical objects, associated with thawing - freezing process. Increasing thawing of Yedoma permafrost may have positive feedback for greenhouse effect when gases emitted to the atmosphere. The presence of artificial reservoirs in permafrost environment gives an additional effect for deeper thawing for active layer due to seepage development. We have emergency situation when seepage occurs in permeable talik zone adjoining to reservoir or directly in dam body. Hydro Units are natural laboratory for the study the interactions between permafrost environment - hydrosphere - climate. We present results of geophysical monitoring on hydro technical objects of Western Yakutia. Complex of discussed geophysical techniques for verification of permafrost state near Hydro Units have included electric, electromagnetic, ground penetrating radar, hydro location, thermal and radio wave measurements. Geophysical information was used for constructing reliable numerical models of interaction of human impact (Hydro Units) on the system "Permafrost-Reservoir-Climate". Another part of our work is spatial electric monitoring of the permafrost state near injection wells on several oil fields in Western Siberia. We present an experience of such monitoring at a multiple-well platform of an oil fields. Changes of permafrost physical state near hot injection wells investigated using radio wave methods of cross well surveys.