Rens Fish Farm

Rens Fish Farm is situated in River Sønderå, a tributary to the River Vidå.

The fish farm was established in 1969 as a traditional Danish fish farm with earth ponds and water intake from - and outlet into - the stream. The weir was build with a fish ladder, but nevertheless constituted a total block for the upstream migration of houting.

Model fish farm
Rens Fish Farm wasconverted into a so-called model fish farm in 2005. Contrary to an ordinary low-tech fish farm, modern high-tech model fish farms do not use water from the stream but entirely recirculated ground water.

Furthermore, the amount of discharge water is minimized and led to a water treatment plant. A model fish farm does hence not need the stream as water supply or as a drain. Thereby the weir becomes unnecessary.

The Houting-project
The weir will be completely removed, and the former difference in water levels upstream and downstream the weir will be equalised by new meanders. The meanders will be constructed with a 0.4 m thick, gravel and stone bed riffle with a total length of 230 m . The mean gradient of the riffle will be between 3 and 4 ‰.

The heavily modified section of Sønderå along the fish farm will be filled up with earth from excavation of the new meandering section.