Jettenbach I Run-of-River Plant

The Jettenbach power unit is part of the Jettenbach-Reith weir system in the municipality of Aschau am Inn.

Man in the kitchen

250 households 

supplies the Jettenbach I power plant

Conscious of the environment

850 fewer
tonnes of CO2*

Fish bypass

Fish bypass available



Built in 1923 as the first weir on the Bavarian section of the Inn.


*Source: ENTSO-E Production 2017

The Jettenbach I power plant was completed and opened in 1924. It dams the Inn over a distance of 8 km. A single-blade Francis turbine processes the minimum water flow rate of 5 m3/s and generates an annual average of approx. 1 GWh of electricity.

In the Jettenbach storage area, just before the weir, some of the dammed water is passed through a contactor system into the Innwerkkanal and from there to the Töging run-of-river power plant.
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Image from the Location

Owner VERBUND Innkraftwerke GmbH
Operator VERBUND Innkraftwerke GmbH
Commissioning 1924
Type Run-of-river power plant
Country Germany
Region Bavaria
Waters Inn
Output 01 MW
Annual output 1,100 MWh
Turbine Francis
Connectivity Fish bypass
Environmental protection at VERBUND

Ecology & environmental protection

The Jettenbach power plant is equipped with a fish bypass and has a continuous flow. All hydropower plants on the Inn comprise:
• the machinery hall with the turbines
• the weir systems for flood release
• the dams and dikes for the accompanying flood protection, and,
• the pumping stations and ditches, which guarantee agricultural use that existed before construction of the barrage.

The VERBUND hydropower plants on the Inn are therefore not only plants for generating electricity but also ensure flood protection in the region. VERBUND also focuses on improving the ecological conditions at individual sites and on restoring natural river landscapes. We implement a large number of measures in this regard: from creating continuity of flow with fish bypasses through to giving structure to bodies of water and connecting tributaries. In order to guarantee habitats for fish with all their habitat requirements, management of the gravel banks in the near-natural fish bypass or below the dam stage is additionally carried out. The maintenance of sediment continuity through sediment management, a topic of the EU Water Framework Directive (WFD) for species conservation in man-made rivers, is also an important component for the long-term conservation of fish fauna.
Our latest conservation projects
Weir system: The weir system has 6 openings with a clear width of 17 metres. The weir is closed with double gates that are hung on winches with link chains. The drive unit is housed in a reinforced concrete superstructure clad in wood as a weir construction. On the left, connected almost perpendicularly, are 21 channel inlet openings with a width of 5.6 metres each, which can be closed by 2 sluice boards each. In the building on the right is a small power plant that processes the remaining minimum water flow rate of 5 m³/s with a single-blade Francis turbine. Road bridges pass over the weir system and the inlet structure. The weir is designed for 4,000 m³/s, the highest known water flow rate at the time was 2,900 m³/s and it was built in 1899.

Innwerkkanal between Jettenbach power plant and Töging power plant: The water held back at km 128 by the Jettenbach weir is fed into the canal through the sluice system. It was the first weir structure on the Inn in Bavaria in 1923. The 20 km-long headrace channel begins with a 300 metre-long and 125 metre-wide cleaning basin, in which the material carried along should settle when the flow velocity reduces. To increase leak-tightness and reduce roughness, the canal, which narrows after 6 km from 52 metres to 30 metres in width at the surface and 8 metres in depth, was lined with concrete. The average water velocity with the least possible loss of gradient is 2.0 m/s.