There's a River Gauge at the Blau in Ulm, Baden-Württemberg, Germany.
There are two gauges. One is a 2,50 Meter high river gauge, the second is a 1,70 Meter high river gauge at the Bridge of "Magirusstrasse" at the Blau.
The blue is a 22 km long river on the southern edge of the "Schwäbischen Alb" in the east of Baden-Württemberg, flows through the city of Ulm leads in the upper Danube.