evidence: Article I (1) The riparian States of Lake Constance, namely the Federal Republic of Germany, the Republic of Austria and the Swiss Confederation, undertake to observe the provisions of this Agreement when withdrawing water from Lake Constance. [...] Article 2 (1) For the purposes of this Agreement, Lake Constance comprises the Upper Lake and the Lower Lake. (2) For the purposes of this Agreement, the region of Lake Constance comprises, in the territory of the Federal Republic of Germany, the hydrological catchment area of the lake, in the territory of the Republic of Austria, the hydrological catchment area of the lake, and in the territory of the Swiss Confederation the hydrological catchment area of the lake lying within the cantons of Appenzell (Outer Rhoden and Inner Rhoden), St. Gallen and Thurgau, the catchment area of the Tur in the canton of Thurgau - excluding the catchment area of the Murg above the commune of Frauenfeld and the catchement area of the Sitter.