People & environment
A total of 19 buildings within the study perimeter were classified as OMEN. The magnetic field was calculated for all OMENs. In 18 OMENs, the system limit value of 1 microtesla was maintained. In one OMEN, the system limit was exceeded slightly – a dispensation has been granted for this.
The new line routing is used in the entire project perimeter south of the existing building zones and residential areas. By moving the line from the banks of the Rhône and out of the open agricultural land to the wooded hillsides, the potential conflict of the existing 220 kV line from the construction zones in several communities will be resolved. In terms of the landscape, there will be a general improvement over the existing situation.
Due to the bundling with the 132 kV railway power line and the 65 kV line on the same pylons as well as to the higher voltage, however, the pylons will be taller than the existing 220 kV line.
The majority of the pylon sites are located in the forest. Other locations are used intensively for agriculture or include semi-dry meadows and extensively grazed areas.
In the spring of 2018, deforestation work was carried out along the transmission route. This was necessary to ensure safety on the construction site and safe operation of the line. An approximately 30-metre-wide corridor was cleared over a distance of around 16 kilometres. Trees and shrubs are beginning to grow again in this area. Over time, this will allow the line to blend into the landscape better.
To implement the line, a total area of 15,288 m2 of forest need to be cleared for the pylon locations. The temporary clearing of 22,572 m2 is required to provide access to the building sites and pylon locations. Suppression is necessary for an area of 292,471 m2.
The required deforestation and clearance easements were authorised in the approval procedure. Strict requirements have also been imposed on Swissgrid with the construction permit. This includes checking whether additional safeguards against avalanches and snowslides are necessary after the deforestation. A definitive assessment of the situation and the agreement of suitable measures was only possible after the deforestation. For this purpose, Swissgrid commissioned an expert opinion from the Valais engineering firm geoformer igp AG.
Planned protective measures include snow barriers and tripods made of wood as well as young trees in different clearings in the forest along the transmission line. On the one hand, this guarantees that the forest roads on Frid alp and in Chäserstatt, which are used all year round, remain safe during winter. On the other hand, this ensures the growth of the forest in the strip covered by the height easements. The situation is safe for the population. The measures allow the forest to fulfil its long-term role of protecting against avalanches without restriction.
- Amphibians / reptiles / small mammals / fish
No special habitats such as ponds will be affected by the construction work. No interventions in fishing waters are to be made.
- Wild Game
During construction, care will be taken to ensure that game is not disturbed, particularly during the hunting season. As almost all pylon locations are approached by helicopter, these helicopter operations will disturb the wild game only for a limited time.
No serious conflicts for grouse, golden eagles and migratory birds are to be expected. By moving the lines near Mörel, the potential for conflict for the peregrine falcon has been largely defused. The autumn migration is disturbed to only a small extent, as the line runs parallel to the direction of the valley along the slope.
Vegetation and habitats
The interventions are local and cover small areas; they will not lead to the disappearance of larger habitats.
- During the construction phase: The areas of intervention in the soil include the installation locations, the pylon locations and any temporary roads that are required
- During the operating phase: The interventions remain limited to the pylon locations
The following overhead lines are to be dismantled with the commissioning of the new 380 kV line:
- existing Mörel - Ulrichen 220 kV overhead line of Swissgrid
- 65 kV Ernen – Mörel 1 overhead line of Valgrid SA
- 65 kV Ernen – Mörel 2 overhead line of Valgrid SA
- 65 kV Ernen – Ulrichen overhead line of Valgrid SA
- 65 kV Heiligkreuz – Fiesch overhead line of Gommerkraftwerke AG between Binnegga and Fiesch
The three 65 kV Fiesch – Ernen – Heiligkreuz, Mörel – Ernen and Ernen – Ulrichen overhead lines will be installed underground between the Fiesch power plant, the Ernen power plant and pylon No. 1461.
As the forest cover of the reforestation area will occur naturally, alternative measures were defined in addition to a real substitute:
- Tunetsch cultivated landscape: creating a new wet biotope
- Hockmatte-Schärtegga and Binnachra-Sengg cultivated landscapes: extension of the ecological network, keeping open the in-growth areas
- keeping various dry meadows and pastures open