Mühlkanal
A Mühlkanal ( Mühlengraben , Mühlgraben , Mühlgang , also Mühlenbach or Mühlbach , regionally also Mühlenfließ , [in the Eifel] Mühlenteich ) is a channel that was created for the operation of water mills .
The canal usually branches off the natural course of a flowing water above the mill and feeds part of the water into the mill as impact water . The feeding part of the mill ditch is called the upper ditch . Any existing natural river bed is preserved and serves as a flood . Below the mill, the canal usually reunites with the feeding water. This part of the mill ditch is called the underground trench . More rarely, the entire river in the area of a mill is straightened and regulated so much that it is called a mill ditch .
The discharge from a main body of water , the tee , is often regulated by a weir . Then one speaks of a moat .
The Mühlkanal or Mühlgraben is always an artificially created or at least artificially managed, canalized body of water; a “Mühlbach” can also be a completely natural body of water (possibly provided with a dam). Many mill streams are completely normal streams, they are called that because at least one mill is attached to them.
Purpose and construction
The prerequisite for the operation of a water mill is a steady flow of water and a certain amount of water . In natural water beds, the water volume, gradient and flow speed are often not sufficient, so that when mills were built in the past centuries, water had to be channeled through a ditch or channel to the mill wheel. This was particularly true of overshot mills. The mill channel was necessary here to let the water fall from above onto the mill wheel. Therefore, watermills are rarely located directly on a natural watercourse.
The length of a mill canal can range from a few meters to a length of one kilometer. On average, the lengths are a few hundred meters. The shape of the water wheel and the gradient of the water were decisive for the length. Through weirs and sluices at the beginnings and ends of the mill canals, the water could mostly be diverted out and also diverted, so that an exact regulation of the head water volume was possible. The possibility of draining the sewer was particularly necessary in the case of a low flow rate or a low flow velocity, since such sewers tend to become more silted and therefore had to be cleaned regularly.
The trenches themselves can be very different. From uniform transverse profiles with a continuous bank and bed construction made of concrete or natural stone to loose bank reinforcement made of compacted soil, all construction methods are conceivable and implemented.
Mühlkanal habitat
Very heavily built-up channels are usually relatively poor in species . Many individuals of one species can live there, but biodiversity is usually low there. The reason for this is the lack of pronounced sole and edge structures, which are immensely important for many small organisms and fish as a habitat and for foraging. On the other hand, the abandoned or poorly built-up mill canals are of growing ecological importance because, with their often different properties compared to the original waters, they create a new habitat for many animals and plants.
photos
Tee of a Mühlkanal (from Klemmbach , above the channel on the right, Müllheim (Baden) )
A mill canal built on stilts (center):
Glade Creek Mill ( West Virginia )
A very short, brick mill canal (directly in front of the mill building): Odilienmühle in Göttingen
literature
- Jutta Böhm: Mill bike tour. Routes: Kleinziegenfelder Tal and Bärental , Weismain environmental station in the Lichtenfels district, Weismain / Lichtenfels (Lichtenfels district), 2000, 52 pages (numerous illustrations, canton)
