CHANGES IN THE QUALITATIVE CHARACTERISTICS OF GROUNDWATER OF THE OSSETIAN ARTESIAN AQUIFER.

The basis for the research was the GIS project, which includes groundwater monitoring data on the territory of the Republic of North Ossetia-Alania. The paper presents generalized materials on fresh groundwater and comparative analysis of their quality change during water intake exploitation on the territory of the Republic of North Ossetia-Alania. Special geoinformation system (GIS) including groundwater parameters data for about 20 years of monitoring was developed. The results of chemical analyzes of groundwater for different years are systematized. The characteristics of deformation changes in aquifers and their relationship to surface waters are given. The evaluation of the groundwater protection against natural and anthropogenic pollution is given. The methodology for calculating of protective sanitary zones for water intakes with various hydrogeological conditions is developed, and measures for sanitary protection and revealing of pollution sources are offered (reasons for increasing hardness and mineralization of fresh groundwater in the industrial zone of Vladikavkaz city). Based on the investigation results, the conclusions on possible sources of hardness increase and deterioration of groundwater quality in the Ossetian artesian aquifer were drawn. [ABSTRACT FROM AUTHOR]