More fish for the Lafnitz

Restoration measures create new habitats for fish and other organisms

The restoration measures for the IRIS project on the Lafnitz are in full swing. On 28 November 2024, the ground-breaking ceremony took place. The measures are transforming the Lafnitz along the Styrian-Burgenland border in Rudersdorf into a structurally rich and healthy river with many key habitats for native species. Fish in particular, but also many other animals and plants will benefit from the measures.

In addition to the structure-improving measures, measures are also planned to improve flood protection and protect residential areas in the event of extreme weather events.

The following measures are planned to improve the ecological quality and flood protection of the Lafnitz:

Flood protection Fritzmühle:

To protect the Fritzmühle building and the settlement area behind it, the construction of a flood protection dam and a flood protection wall integrated into the mill building is planned.

Removal of the existing dam:

In order to give the Lafnitz a corridor for its own dynamic development, the existing flood protection dam will be moved back. This self-dynamic development will be initiated by removing the existing bank protection.

Improving aquatic ecology:

Structural improvement measures will enhance aquatic ecology. The measures will create important key habitats that will benefit fish in particular, but also other animals such as amphibians.

The following measures are planned:

Connection of an oxbow lake in the area of the Fritzmühle (mill), where the Lafnitz used to have a low point due to mill utilisation.
Removal of bed sills and bank stabilisation
Construction of groynes, pools and fords
Creation of riparian forests and forest improvement measures in the riparian area
Creation of three water bodies for amphibians

Removal of the existing water division

The Lafnitz outflow used to be divided in the project area. A diversion by means of a pipe channelled water into the course of the Lafnitz that was previously used by the Fritzmühle (mill). This diversion will be dismantled as part of the project. The main reason for this is the declining discharge of the Lafnitz – also due to climate change. From an ecological point of view, it is counterproductive to divide up this low discharge during periods of low flow.

Temporary and permanent forest clearances are necessary for the project. In order to compensate for the permanent loss of forest areas, replacement afforestation will be carried out outside the project area with local trees and shrubs.

Lafnitz Rudersdorf Facts

Investment costs

€

Of which:

€

EU funding

€ 27.000 of the costs are covered by a contribution from stakeholders

Construction time

Start of realisation: Nov 2024

In order to minimise disturbance, construction work in the river and on the river banks will be carried out outside the spawning season of the FFH fish species (March-June). Clearing work will be carried out outside the bird breeding season.

Purple Lafnitz

A very special natural highlight can be experienced in the months of May and June. At this time of year, the Siberian iris transforms many a meadow along the Lafnitz into a purple carpet of flowers. An excursion is worthwhile. One way to discover many places along the Lafnitz in a short period of time is the Lafnitz Valley Cycle Path, a cycle path with a length of around 70 kilometres, which also takes enthusiastic cyclists directly past both LIFE IRIS pilot measures.

Timeline: Measure Lafnitz Rudersdorf

Measures Site Plan

Lageplan downloaden

Download Site Plan

Why are the restoration measures on the Lafnitz necessary?

The LIFE IP IRIS project aims to combine flood protection with ecological objectives. This is achieved primarily through the use of nature-based solutions. The IRIS project is therefore bringing parts of rivers back closer to their natural form as part of the river restoration measures. In addition to improved flood protection, the measures on the Lafnitz are primarily intended to help the fish population recover in the coming years.

More fish in the Lafnitz

Even though the Lafnitz can flow relatively freely in some sections and meanders through the landscape with its typical bends, its ecological status is inadequate to poor in many places. This poor classification is mainly due to the lack of fish, which is probably due to a lack of suitable habitats – especially for juvenile fish.
The planned measures to improve the structure of the Lafnitz will create important habitats for fish and other organisms. This will allow the fish population to recover in the coming years and improve the ecological quality of the Lafnitz.

Improved flood protection

Many residential areas are already protected against floods with a medium probability (HQ100) by flood protection systems. In other areas, the planning of such facilities is already well advanced. Nevertheless, damage would still occur in these areas in the event of a major flood. The planned measures ensure that residential areas are protected even in the event of extreme weather events.