The Rehbach rises about 400 m north of Homberg at an altitude of 606 m above sea level. NN. It first flows in a south-easterly direction through deer and then reaches the Krombachtalsperre. After flowing through the reservoir, the Rehbach flows mainly in northeastern directions. After flowing through Mademühlen, the stream is dammed again by the Driedorftalsperre. The barrage of this dam is located on the southern outskirts of Driedorf, although the village itself is not traversed. Further flowing in northeastern directions, the Rehbach passes Guntersdorf (Herborn) on the left bank of the river with another dam. Then it touches Merkenbach north. Here, the Rehbach water is stored in a pressure reservoir (Merkenbacher water tower) and fed to a turbine at the reservoir in Sinn (Hesse) before the brook, after crossing under the federal motorway 45, is on the right at 196 m above sea level. NN flows into the dill.
In terms of length, gradient and amount of water, the Rehbach was one of the best-used creek systems in Germany for energy production as early as the 1930s
. Nowadays the water quality is so good that freshwater mussels have been settled here.
With a height difference of 410 m between the source and the mouth, the mean bed slope is 20.5 ‰. The 48.666 km² catchment area is drained to the North Sea via the Dill, Lahn and Rhine rivers.
Source: Wikipedia