Source of the Danube of Baden): “Danube, the biggest river of Germany, rises at the Martinskapelle in a wild and lonely area of the Black Forest, is called Brege at its origin and forms the river Danube in Donaueschingen where it is unified with the Brigach." (German original: „Donau, der größte Fluß Deutschlands, entspringt bei der Martinskapelle in einer wilden und einsamen Gegend des Schwarzwaldes, heißt am Anfang Brege… und bildet erst in Donaueschingen, wo sie sich mit der Brigach vereinigt, die Donau.“) The identification of the main spring in the uppermost Bregtal (also called Katzensteig) is dependent on a defining convention: Instead of
International Commission for the Protection of the Danube River and the ground water resources. The ICPDR’ legal basis is the “Convention on Cooperation for the Protection and Sustainable use of the Danube River (Danube River Protection Convention)”, generally referred to as the “Danube River Protection Convention” or “DRPC”. It commits the contracting parties to join their efforts in sustainable water management, including conservation of surface and ground water, pollution reduction, and the prevention and control of floods, accidents and ice hazards. The convention was signed in Sofia, Bulgaria, in 1994 and came into force in October 1998. The ICPDR was created to implement the Danube River Protection Convention (DRPC).