The Modau is a 44-kilometre-long right tributary of the river Rhine running through the German state of Hesse. Historically, there have been many watermills on the river and its tributaries, giving rise to the name Mühltal, a district through which the river flows. It passes through Darmstadt, and Ober-Ramstadt, and Pfungstadt, and flows into a branch of the Rhin…The Modau is a 44-kilometre-long right tributary of the river Rhine running through the German state of Hesse. Historically, there have been many watermills on the river and its tributaries, giving rise to the name Mühltal, a district through which the river flows. It passes through Darmstadt, and Ober-Ramstadt, and Pfungstadt, and flows into a branch of the Rhine in Stockstadt am Rhein.