The unprecedented degradation of freshwater ecosystems due to the rampant exploitation of water resources re-establishes the importance of preserving freshwater ecosystems in order to ensure their continued viability that supports the attainment of sustainable development. This concern is addressed in Article 20 of the 1997 Watercourses Convention that specifically provides for the preservation of ecosystems of international watercourses. However, the interpretation and the subsequent application of this obligation are complicated by the proliferation of international instruments concerning the environment, which leads to the fragmentation of international law. In response to the apprehension raised over the undesirable consequences of the fragmentation of international law, the potential of Article 31(3)(c) of the 1969 Vienna Convention as an interpretative mechanism that enables the systemic integration of rules has come into the limelight. The objective of the present thesis, titled ‘Preservation of Ecosystems of International Watercourses and the Integration of Relevant Rules’ is to develop a interpretative framework for the operationalisation of Article 31(3)(c) that allows the full realisation of its potential as a tool of integration. A three-tier operationalisation framework that re-interprets the salient features of Article 31(3)(c) through the prism of an interactional understanding of international law is developed and executed through Chapters Two to Eight, where Chapter Nine provides a general conclusion of the thesis. The reconstruction of existing interpretation of Article 31(3)(c) provides a new understanding of this Article, which enables the realisation of its systemic integration potential. The application of this framework of operationalisation in the interpretation of the obligation to preserve ecosystems of international watercourses stipulated under Article 20 reflects contemporaneous development in international environmental law, and enhances the normative content and scope of Article 20.

Recent transboundary disputes between the United States and Canada and in particular, the dispute concerning Devils Lake outlet, call for an improvement of the agreements between the two countries that govern North American international watercourses. One way to do so is by assimilating the cooperative spirit contained in the more recent 1997 U.N. International Watercourses Convention and incorporating its guidelines for balancing different principles and interests into the 1909 Boundary Waters Treaty between the United States and Canada. This paper analyzes the different theories and main international legal instruments in the area of transboundary waters within the context of the issues arising out of Devils Lake and its outlet. It is proposed that the Boundary Waters Treaty be vastly improved by increasing the participation of both the Canadian provinces and the American states as well as renewing and enhancing the role of the International Joint Commission.

Recent transboundary disputes between the United States and Canada and in particular, the dispute concerning Devils Lake outlet, call for an improvement of the agreements between the two countries that govern North American international watercourses. One way to do so is by assimilating the cooperative spirit contained in the more recent 1997 U.N. International Watercourses Convention and incorporating its guidelines for balancing different principles and interests into the 1909 Boundary Waters Treaty between the United States and Canada. This paper analyzes the different theories and main international legal instruments in the area of transboundary waters within the context of the issues arising out of Devils Lake and its outlet. It is proposed that the Boundary Waters Treaty be vastly improved by increasing the participation of both the Canadian provinces and the American states as well as renewing and enhancing the role of the International Joint Commission.

Protection of International Watercourses The purpose of the Thesis is to analyze the present degree of the protection of international watercourses and to describe three main levels: international law, European law and Czech law. Although the issue of environmental protection and sustainable use of international watercourses is considered to be one of the most significant problems of the present society, the topic has been rather neglected by Czech scholars. Analytical, logical and historical methods were primarily applied in the study. The thesis is composed of four chapters, which are furthermore divided into sections and subsections. The term "international watercourses" usually designates rivers, lakes and groundwater sources shared by two or more states. Chapter one deals with international customary law (especially equitable utilization and no harm principle), international treaty law (global and regional cooperation as well as non- binding documents) and selected major cases important for the evolution of protection of water. In the past, international water law concerned mostly with allocating water supply between riparian states. Nowadays the law concentrates more on permissible uses of watercourses and preventing pollution of freshwater resources as well as water ecosystems. The second...