Krassach River


The Krassach is a left tributary of the Weismain about 7 kilometers long, which flows into the Main near Altenkunstadt in Upper Franconia.

Geography

History and description

From its source, the Krassach meanders through the Bärental, maintaining its natural flow, although some straightened sections exist. The Mühlbach of the Herbstmühle is relatively short, about 370 meters, and rejoins the brook immediately after passing the mill. Around 500 meters further, another Mühlbach branches off, belonging to the Krassacher Mühle. This stream, about 600 meters in length, runs mostly parallel to the Krassach, about 50 meters apart, and reunites with the brook at the end of the Bärental.
As the Krassach continues, human interventions have straightened their course, particularly in the Krassach district of Weismain. It flows past several fish ponds used for trout breeding and is joined by its only significant tributary, the Niestener Mühlbach, on the left side near Niesten. About 300 meters downstream is the Rumpelwehr, a natural waterfall falling down over two sintered and moss-covered steps. Following this waterfall, a third Mühlbach splits off from the Krassach. It starts as a free-flowing stream and is later channeled through the town area of Weismain, eventually emptying into the Weismain River near the Püls brewery. The Weismain Mühlbach was historically used to power the Kastenmühle, among other purposes.
For approximately 250 meters along the Niestener Straße, the Krassach is canalized. Continuing eastward, it flows between fields towards Altenkunstadt along the St2191 road. Just before reaching its mouth, it passes by the joint sewage treatment plant of Altenkunstadt and Weismain and is used as a freshwater supply. The Krassach finally merges with the Weismain River south of Woffendorf.

Biology

Flora

The entire length of the Krassach River is flanked mainly by alder and willow trees. The upper reaches have increasingly narrow stream-ash forests, especially near the calcareous spring. During spring, dense stands of the counter-leaved spleenwort also flourish in these areas. The narrow groves of alder, ash, and willow along the riverbanks are remnants of former floodplain forests, which were mostly cleared through human land use during the Middle Ages, leaving only small remnants behind. However, these remaining groves play a crucial role in protecting the stream. They act as buffer strips between the river and adjacent agriculture, offering shade that helps keep the Krassach from warming. The stream bed and the riparian areas are richly structured, except for the straightened sections in Krassach and Weismain, and shallower areas alternate with deeper ones. Also, in its upper reaches, the Krassach has a lively alternation of feeder-rich, faster-flowing and shallower, slower-flowing sections of water.

Fauna

The Krassach River is a habitat for various species, including bullheads, brook lampreys, and brown trout. Additionally, stoneflies, small and large dragonfly larvae, mayfly larvae, caddisfly larvae, gammarus fossarum, and flatworms thrive in its waters. There have been occasional sightings of fire salamanders and damselflies as well.