More Room for the Enns

Widening of the Enns increases natural river dynamics

Near Stainach, the Enns is being revitalized to make it more vibrant again. In the area of the Leistenbach confluence, the heavily regulated river is being widened to give it more space for its natural development.

In the widened riverbed, three so-called starter channels are created – narrow, deliberately designed watercourses that guide the flow and reshape the river dynamics. They act as a kind of ‘kickstart’ for natural development and will be further shaped by the river over time. Combined with targeted flow control, natural processes are set in motion and natural dynamics of the watercourse are restored.

In this way, varying zones of depth and flow are created. Over time, this develops into a diverse aquatic landscape with a mosaic of valuable habitats for animals and plants.

The revitalization measures are based on guiding principles and objectives for the Enns, which were developed within the context of the River Development and Risk Management Concept (GE-RM) involving a wide range of stakeholders.

Enns Stainach Fact Sheet:

Widening of the Enns

Total costs

€

Lenght of Revitalization Section

Construction Period

July 2025

July 2026

Due to the nearby airfield, it was suspected that munitions had been disposed of in the Enns after the end of the war. The construction site was therefore initially not cleared for work, which led to delays. A preliminary study then identified a suspected contamination area at the eastern end of the construction site, which is why a safety briefing was required before construction could begin.

When the Enns Valley Blooms

A very special natural spectacle awaits visitors in the Styrian Enns Valley at the end of May: when the Siberian iris (also known simply as iris) blooms, the meadows around Trautenfels Castle are transformed into a vivid violet carpet of flowers. These species-rich meadows are not only beautiful to look at: they also provide a valuable habitat for many rare animal species – such as ground-nesting meadow birds.

Trautenfels Castle is just a few minutes away from our pilot measure and is a particularly worthwhile excursion destination during the iris flowering season.

Timeline: Measures Enns Stainach

Measures Site Plan

Enns Steiermark - Maßnahmen Lageplan Life IRIS

Lageplan downloaden

Measures Site Plan

Download Plan

Why is the Enns near Stainach being revitalized?

In the project section, the Enns is heavily regulated: as part of the Enns river regulation works, it was straightened and narrowed. In addition, the hydropeaking operations of the Sölk and Salza power plants significantly affect the water level. The planned measures aim to make the Enns more dynamic in the long term – with structures that are largely self-sustaining, continue to develop on their own, and require only minimal external intervention.

Before the river regulation works, the Enns had a very different character: historically, the river began to transition from a wandering to a meandering river type roughly in the area of present-day Stainach – a character that was largely lost as a result of the regulation works. The project area is located in a straight river section and already shows a significantly reduced gradient compared to the upper reaches. All of these characteristics of the area were taken into account during the planning of the measures, so that a piece of the river’s original character can be restored to the Styrian Enns Valley.