Ruhr (river) Ruhr (river) __notoc__ The Ruhr is a river in western Germany (North Rhine-Westphalia), a right tributary (east-side) of the Rhine. The source of the Ruhr is near the town of Winterberg in the mountainous Sauerland region, at an elevation of approximately 2,200 feet (670 m). It flows into the lower Rhine at an elevation of only 56 feet (17 m) in the municipal area of Duisburg. Its total length is , its average discharge is 79 m³/s (cubic metres per second) at Mülheim near its mouth. Thus, its discharge is, for example, comparable to that of the river Ems in
Battle of the Ruhr the Ruhr, Bomber Command estimated about 70% of their aircraft losses were due to fighters. By July 1943, the German night fighter force totalled 550. Through the summer of 1943, the Germans increased the ground-based anti-aircraft defences in the Ruhr Area; by July 1943 there were more than 1,000 large flak guns (88 mm caliber guns or greater) and 1,500 lighter guns (chiefly 20 mm and 37 mm calibre). This was about one-third of all anti-aircraft guns in Germany. Six-hundred thousand personnel were required to man the AA defences of Germany. The British crews called the area sarcastically "Happy Valley"