VERBUND to restore environmental passability on the Zemmbach river by 2027

€2.7m investment in near-natural habitats and fish migration in the Zillertal Valley

In the Zillertal Valley, VERBUND is taking another important step towards enhancing the environmental quality of the Zemmbach river. By April 2027, a multi-stage project to restore passability will permanently remove existing migration barriers for fish and aquatic invertebrates and make the habitat more natural.

Project start 2026: Near-natural ramp in the tailrace of Mayrhofen power plant

The first construction phase in the tailrace of Mayrhofen power plant started in mid-January 2026 and will be completed in April. This is creating a temporary bypass measuring around 160 metres in length. Once the Zemmbach has been diverted, the existing technical ramp at Kohlstatt will be rebuilt. A flattened, ecologically improved ramp measuring around 90 metres in length will then be built across half the width of the river. With near-natural basin structures, changing water depths and variable water flows, stable migration routes for all life stages of fish and flow-calmed retreat areas will be created in the future, contributing to an increase in the structural diversity of the stretch of water.

Synergy effect for sports and nature: the measures combine ecology and recreational sport because the new body of water will also be easier for kayakers and rafters to navigate.

Construction continuation 2027: Headrace channel and ramp at Kreuzlau

Work will resume at the beginning of 2027. Near the Roßhag power plant, the headrace channel between the power plant and Stillup reservoir crosses the Zemmbach underground. The stream bed, which is now reinforced with armour stone, will be made environmentally passable with new structural elements and the erosion section on the downstream side will be protected against unwanted deepening.

In addition, the Kreuzlau ramp will be rebuilt in a more natural style similar to the Kohlstatt ramp. This enables fish passability and also improves navigability for kayakers and rafters.

According to current plans, all work will be completed by April 2027 and the construction areas dismantled and ecologically restored – the passability of the Zemmbach will thus be established in these areas.

Investment in nature and the region

“VERBUND is investing EUR 2.7 million in restoring the passability of the Zemmbach and setting an important milestone for water ecology in the Zillertal Valley. The newly created structures allow fish to migrate upstream and downstream. Using an accompanying professional monitoring system, we can make adjustments if necessary and thus ensure long-term success,” said VERBUND Plant Group Manager Marco Fiegl.

Multiple benefits of the project:

• Restoration of connectivity and migration corridors along the Zemmbach
• Strengthening fishing and enhancing aquatic ecology
• Improving the quality of the landscape
• No traffic restrictions during construction work

About VERBUND in the Zillertal Valley:

VERBUND is Austria’s leading energy company and one of the largest producers of hydroelectricity in Europe. The company generates around 98% of its electricity from renewable energies, primarily hydropower. In the Zillertal Valley, VERBUND operates nine hydropower plants with around 1,260 MW turbine capacity, 695 MW pumping capacity and annual generation of around 1.7 TWh. This ensures that 500,000 private households are supplied with green electricity from hydropower.

Between 2010 and 2025, regeneration and expansion projects with an investment volume of around EUR 210 million were implemented.