Amphibian escape ladder
The amphibian escape ladders, frog ladders or amphibian gully pot ladders allow amphibians and other animals such as reptiles, shrews, mice, etc to exit from storm drains, light shafts, ventilation shafts and other death traps.
As material for the amphibian escape ladders for the drains certain slope mats, embankment mats or crawl mats are used. All of these mats are made up of a plastic mesh. Certain mats such as the “Sytec Terramat S” from Sytec Bausysteme AG have a polyethylene net on the back (compare Figure 2). This polyethylene net must be removed before assembly in the storm drains, as otherwise too much organic material would get stuck in the amphiban escape ladder. It can be used as an amphibian escape ladder for light shafts (compare Figure 6). If the manhole cover has no slots, the amphibian escape ladder must be fixed to the shaft wall with dowels, screws and metal plates (compare Figures 3 and 4). In the case of manhole covers with drainage openings, the amphibian escape ladder can be attached to the manhole cover using metallic cable ties (compare Figure 5). The installation inside the storm drains (compare Figure 1) has advantages that the mat is more protected from mechanical stress due to the drain opening and UV radiation. The tiny hole (5 mm) protects rather than harms the shaft. The tiny hole allows the infiltrated water to drain away instead of freezing and blasting the concrete.
An instruction for installing the ladder to the storm drain cover can be found at the bottom as a PDF download. The ladder fixed to the storm drain wall does not differ at the bottom from the ladder fixed to the storm drain cover. Both variants immerse only a few centimeters into the water and thus do not reach the mud layer.
A polyethylene net, ofthen also available as a bird protection net, can be used in light shafts (comparge Figure 6). There it is mounted in the corner with a weight stone at the bottom so that it is easy to find. In the case of very large light shafts, several corner can be provided with this system. The polyethylene net is an inexpensive and practical option. The polyethylene net costs a few cents and can be offered free of charge to private customers. In addition, it can be installed even when the light shafts covers are screwed on, so there is no need to enter completely blocked cellars. If slow worms or smaller snakes are caught in the light shaft, however, one should use the claw mats or other systems. However, hardly any reptiles were found from numerous examined light shafts.
From a shaft depth of 2 meters or in the case of permanently open basement windows without fly screens, the light shaft should be covered (compare Figure 7).
Time-lapse videos of the amphibian escape ladders
Instruction for the installation of the amphibian escape ladders to the storm drain cover:
Montageanleitung Amphibienausstiegshilfe* (PDF File)
* The PDF file is in German but has pictures for every installation step.