Reed roller
The reed bed roller (also: reed bed machine, vegetation roller, vegetation machine, reed bed gravel roller) is a combination of a structure made of pressed coconut fibers and reed beds .
description
Reed rollers usually have vegetation completely rooted in the so-called coconut machine (structure made from pressed coconut fibers) and are attracted over several months. In some cases, the reed rollers are only planted after installation: z. B. in the case of an immediately required slope base protection.
history
The use of reed rollers was described a few decades ago for securing the bases of embankments.
Traditionally, a hollow was profiled on site at the base of the slope. A wire mesh was inserted into this hollow and this wire mesh was then filled with gravel / rock material and soil, so that a cylindrical structure was created. Before this roller was closed (using binding wire), pricked sod was inserted and then the entire construction was closed.
This procedure was optimized over time, as weak points such as susceptibility to corrosion and washouts of the substrate became apparent. Based on this knowledge, a further cultivation system for flowing and hydraulically polluted waters was developed.
construction
A reed roller consists of a firmly pressed coconut machine as a vegetation carrier and reed plants . Coconut fascines are cylindrical structures that are covered with a mesh hose (PP, UV-stabilized or natural fiber / coconut ). The plants are selected depending on the location. B. reeds ( Phragmites australis ), sedges ( Carex ) or rushes ( Juncus ).
Their dimensions are usually 2.20 to 3.0 m in length and 30, 40 or 50 cm in diameter. Depending on the diameter, the coconut machine is planted with a corresponding planting density of 8 to 20 per meter. Basically, two thirds of the diameter of the reed roller is installed in the mean water line.
application areas
Reed rollers are used as an engineering biological safety element at the foot of the embankment and in the area of the mean water line. The flexible structure adapts to the unevenness of the river bed or the bank line and prevents erosion and scouring. As a solid element, reed rollers absorb the pressure of the slope and serve as an abutment for further building up the slope .
Reed rollers take over the functions that bongossi , palisades or harder construction methods used to have. In particular due to the increased nature protection , but also taking into account the discussion about the protection of the tropical forest , they are considered an environmentally friendly alternative solution.
Beyond the bank protection, reed rollers help to ensure that the reed can develop and that the ecologically important contact zone water - land can be colonized again for many organisms. The reed plants used initiate a sustainable (re) settlement of the bank . They can also be used to install upstream breakwaters for temporary use. The water body behind it is calmed down and thus offers growth conditions so that the reed beds that are re-established here can be established under optimal conditions. At the same time, the filter action of the reed rollers prevents fine parts of the bank substrate from being washed away.
Individual evidence
- ↑ see u. a. Begemann / Schiechtl “Handbook on natural hydraulic engineering and earthworks”, 1986