Abstract: This article examines the principles of fair and rational use of fresh water resources and the right of a sovereign nation to a part of transboundary fresh waters, their historical establishment, statutorization and explanation of their content on universal and regional levels. A special attention is given to the factors of determination of fairness and rationality of the use of the waters and their interconnection, as well as the international legal regulation of the correlation between various types of use of fresh water resources. In the course of the research the author determined the principles of usage and protection of fresh water resources are unified for international waterways and transboundary watercourses. The fairness of usage means an optimal distribution of water, and rationality – passing measures on maintenance and restoration of water resources to the level that ensures maximal benefit from its usage. The author proves that a fresh water object falls under the sovereignty of a nation due to the fact that the “reservoir” represents a part of the territory of the country.

Abstract: This article examines the principles of fair and rational use of fresh water resources and the right of a sovereign nation to a part of transboundary fresh waters, their historical establishment, statutorization and explanation of their content on universal and regional levels. A special attention is given to the factors of determination of fairness and rationality of the use of the waters and their interconnection, as well as the international legal regulation of the correlation between various types of use of fresh water resources. In the course of the research the author determined the principles of usage and protection of fresh water resources are unified for international waterways and transboundary watercourses. The fairness of usage means an optimal distribution of water, and rationality – passing measures on maintenance and restoration of water resources to the level that ensures maximal benefit from its usage. The author proves that a fresh water object falls under the sovereignty of a nation due to the fact that the “reservoir” represents a part of the territory of the country.

Abstract: This article examines the principle of not causing significant damage to another country during the use of transboundary freshwater sources, its legal content, including the obligation of each state, concept of damage, its limitations, as well as its correlation with the principles of fair and reasonable use of freshwater resources, prevention of polluting the environment, implementation of safety measures, “polluter pays”, and the responsibility to assess transboundary effects. The author analyzes the universal and regional international treaties, as well as bilateral agreements with Russia. As a result of the conducted research, the author determines that the principle of not causing significant damage includes in itself not only the obligation to prevent damage, but also containing the damage in the event that it has occurred, liquidating it, and compensating any damages. The damages should be understood as loss of life due to impact to human health, loss of or harm to property, damage to the environment, as well as expenses for reasonable measures of restoration to the previous state of property or the environment.