Application of the method of transient processes in the prospecting of groundwater in Central Yakutia

Providing the population with high-quality drinking and household water supply is an important state task and determines the socio-economic well-being of the country. Currently, the need for additional water resources is being experienced by the settlements of Central Yakutia. Therefore, it is becoming urgent to search for and use underground sources for uninterrupted supply of water to settlements.

This article discusses the results of geophysical studies using the transient electromagnetic field sounding in the search for groundwater in Central Yakutia in the cryolithozone. The reasons for the use of inductive pulse electrical exploration in cryolithozone conditions are given. The object of study was the locally aquiferous cryogenic-talic Quaternary-Upper Jurassic terrigenous aquifer complex (Q-J3), distributed under the beds of the Lena River and its largest tributaries within the subsurface talics. The geophysical studies were carried out within the Machchia group of lakes located on the territory of the Megino-Kangalassky district of the Sakha Republic (Yakutia).

The transient electromagnetic field sounding is performed in profile mode in the coaxial "Q-q" version. Geoelectric sections were constructed based on the results of electrical exploration. It was established that the section of the studied area has the same type of geoelectric structure. The sections have a pronounced horizontally layered character and consist of alternating electrical anomalous layers with different values of apparent longitudinal conductivity. Based on the results of the processing and interpretation of the electrical exploration work, the NBT-1 test well was drilled to obtain more detailed information about the geological structure of the studied area. A comparison of drilling and electrical exploration data showed high convergence. An analysis of the geophysical data showed that the water-saturated horizons within the studied area are distinguished by reduced values of apparent longitudinal conductivity.

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