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 5). 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 9). 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 6 and 7). 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 8). The installation inside the storm drains (compare Figure 1 – 4) has advantages that the mat is more protected from mechanical stress due to the drain opening.

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.

Figure 1: Amphibian escape ladder attached to the storm drain wall.
Figure 2: Amphibian escape ladder attached to the storm drain wall.
Figure 3: Amphibian escape ladder attached to the storm drain wall.
Figure 4: Amphibian escape ladder attached to the storm drain wall.
Figure 5: „Sytec Terramat“ with the undesirable polyethylene net on the back
Figure 6: Storm drain cover without drainage openings
Figure 7: Amphibian escape ladder attached to the storm drain wall
Figure 8: Storm drain cover with drainage openings and attached amphiban escape ladder

Light shafts

A polyethylene net, ofthen also available as a bird protection net, can be used in light shafts (comparge Figure 9). 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.

Figure 9: Amphibian escape ladder made of polyethylene nets in the 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 10).

Figure 10: Light Shaft Cover

Time-lapse videos of the amphibian escape ladders

Video 1: Alpine newt climbs out of a drain.
© Department of the Environment of the Canton of Aargau
Video 2: Alpine newts climb out of a drain.
© Department of the Environment of the Canton of Aargau
Video 3: Common toad climbs out of a drain.
© Department of the Environment of the Canton of Aargau
Video 4: Yellow-bellied toad climbs out of a drain.
© Department of the Environment of the Canton of Aargau
Video 5: Fire salamander climbs out of a drain.
© Department of the Environment of the Canton of Aargau
Video 6: Slow worm climbs out of a lightwell.
© Department of the Environment of the Canton of Aargau