Environmental care in focus

4 November 2013

Respect for the environment has permeated all ASTA AB’s work at the facility, and several compensatory measures have been carried out for benefit of the protected animals residing in the area: the moor frog, the red-throated diver, the Ortolan Bunting and the Whooper Swan. For example, the company has previously built a rampart, several transportation tunnels and two new ponds to meet the moor frogs’ need for spawning and feeding sites.

The very latest compensatory measure is the construction of a salmon ladder, i.e. a structure on or around artificial barriers to facilitate fish’s natural migration. The fish ladder enables the fish to pass around the barrier by swimming and leaping up a series of relatively low steps (hence the term “ladder”) into the waters on the other side.
The construction of a fish ladder is not easy, since the velocity of water falling over the steps has to be great enough to attract the fish to the ladder, but cannot be so great that it washes the fish back downstream or exhausts them to the point of being unable to continue their journey upriver.

The new fish ladder is now operational, and is located between the entrance to AstaZero and the Volvo Hällered entry. The barrier is an old wall that is part of an old pond construction that has been there for years, and that fish have never managed to swim past. By building three steps from existing stones, the AstaZero builders have decreased the fall height, making it possible for fish to swim all the way up to a creek located nearby.