The study of natural waters of the Kolva saddle by hydrochemical and isotope methods (Perm Territory)

Abstract

Introduction: There are only fragmentary data on the distribution, hydrochemical features, and the conditions for the formation of natural waters in the northern part of the Cis-Ural foredeep within the Kolva saddle. The purpose of this work is to establish the conditions for the formation of the isotopic and chemical composition of natural waters (atmospheric precipitation, surface and groundwater) of the Kolva saddle in the north of the Perm Territory. The methods of isotope hydrogeology have not previously been used in the studied area. The main objectives of the study were to conduct seasonal sampling of water seeps to determine variations in their isotopic and chemical compositions, to establish patterns of changes and relationships between the composition of groundwater, river water, and precipitation, as well as to clarify the genesis of groundwater based on the established patterns. Methodology: Sampling of water seeps was carried out in 2017 and 2018. The samples were taken from the Kolva river and five springs every month for the isotope analysis and every season for the chemical analysis. Samples were also taken from four more springs in early autumn (September) and spring (April). Atmospheric precipitation samples for the isotope analysis were taken between December 2016 and June 2018, two samples were taken for the chemical analysis (in October and June). A total of 106 samples of surface water, groundwater, and precipitation were collected for the isotope analysis and 77 samples were taken for the chemical analysis. Results and discussion: For the first time, isotopic indicators were determined for water seeps and the following regularities were established. The underground waters of the Kolva saddle are fresh and have an infiltration genesis. The composition of groundwater is formed mainly due to the supply of atmospheric precipitation during the periods of snowmelt and heavy rains, as well as the ascending discharge of underlying horizons. Conclusions: A comprehensive isotope and hydrochemical analysis makes it possible to obtain detailed hydrogeological information which is important in order to answer questions relating to the genesis of waters and to assess the state and quality of water resources. This pilot work discusses the data obtained as a result of sampling that was conducted for a year and a half. These data were used to identify relationships between different types of natural waters.