The Brigach is the shorter of the two German rivers that form the Danube river. It has its source at 925 m above sea level in St. Georgen in the Black Forest. After 43 km, it joins the Breg river in Donaueschingen to form the Danube. Length 2,888 km Elevation of the source 1,078 m Average discharge 30 km before Passau: 580 m³/s Vienna: 1,900 m³/s Budapest: 2,350 m³/s just before Delta: 6,500 m³/s Area watershed 817,000 km² Origin Black Forest (Schwarzwald-Baar, Baden- Württemberg... A map of Germany, showing the Black Forest in red. ... In Irish mythology, Breg was the wife of the Dagda. ... Donaueschingen is a city in the southwest of Baden-Württemberg in the Schwarzwald-Baar district. ...