Credit: VdL / Tom Jungbluth

The City of Luxembourg (Ville de Luxembourg - VdL) has confirmed that the first phase of the Pétrusse valley restoration project is set for completion in spring 2023.

On Tuesday 21 September 2021, Luxembourg's Minister of the Environment, Climate and Sustainable Development, Carole Dieschbourg, and Luxembourg City Mayor Lydie Polfer visited the site, where works began back in spring 2020. This visit was an opportunity to take stock of the progress of the work.

The main goal of the ecological restoration of the Pétrusse valley is to restore its degraded and artificial ecosystems in order to return to a more natural state. In this context, the natural conditions of the watercourse must be restored, particularly by removing the concrete bed of the watercourse and by recreating a natural watercourse aimed at improving the balance of flora and fauna, nutrients and water. To achieve this goal, the planting of local plants, but also the felling of certain trees is deemed necessary.

Eventually, the establishment of a grassed recreational area at the level of the playground and the mini-golf course is expected to increase the quality of life and promote relaxation for residents and visitors to the capital.

The Pétrusse restoration project and the overhaul of the adjoining park are being carried out in two construction phases, distinct in time and space.

Phase 1
The first phase of the work, covering the area of ​​the Pétrusse valley located between the mouth of the Alzette and the Bourbon lock, began in spring 2020 and will be completed in spring 2023 in order to represent an important element of the LUGA2023, Luxembourg's first major horticultural exhibition.

  • Preparatory work: In order to prepare the ground, a number of trees had to be removed in places where the stream will flow after the redevelopment and widening of the banks. New trees will be planted in strategic places and remarkable trees near the interventions will be protected.
  • Renaturation of the watercourse: In order to recreate a natural morphology of the watercourse, it is a matter of pulling the Pétrusse out of its concrete bed. For this, different successive stages must be repeated in a dynamic process over short sections throughout the valley. The bottom of the stream will be landscaped with natural stones and the banks will be landscaped to create natural habitats for flora and fauna. The planting of a riparian forest and the succession of plants on the banks will allow the creation of an ecological corridor. This renaturation is expected to result in a more natural and slower water flow, which should reduce the risk of flooding.
  •  "First Flush": The implementation of the “first flush” is independent of the other construction phases. This project, the work of which was completed in early 2021 and the interior technical equipment of which is currently being installed, concerns the construction of a "first flush" catchment structure at the level of the connection to the Pétrusse of the city's rainwater pipe network at the Adolphe bridge. Its construction is expected to improve the quality of the water, especially during dry periods followed by intense downpours.
  • Playground / fitness / mini-golf / Bourbon lock / fish ladder / Skatepark: This construction phase includes, among other things, the dismantling of the existing bank walls and bank protection, the implementation of a new bank wall, renaturation and associated earthworks, surface adjustments and planting. In order to maintain a visual aspect in accordance with the UNESCO classification of the fortifications of the City of Luxembourg, natural stone materials will be used to fit out certain new wall elements. Currently, the implementation of the elements of the mini-golf course has begun, followed by the development of the fitness and play areas, the preparation of the relative locations of which is underway. As work progresses in the Pétrusse bed, the landscaping of the banks and the park will follow.

This first phase will end with the installation of a fish ladder and the "Liegewiese" recreational area.

The budget estimate for phase 1 of this land restoration project amounts to €25,909,385.84 (all taxes included). The project is funded by the City of Luxembourg and partially subsidised by the Water Management Fund.

Phase 2
The second phase of the project consists of the renaturation of the Pétrusse valley and the overhaul of the adjoining park between the old Bourbon lock, removed during phase 1, and Rue d'Anvers from spring 2024.

The project for the renaturation and redevelopment of the Pétrusse valley is characterised by the implementation of the following elements:

  • the development of a rest and leisure area at the entrance to the park on the Rue St Ulric side;
  •  the renewal of play areas and sports facilities such as fitness and mini-golf at the entrance to the park, on the side of the rocks of Ville-Haute;
  •  the integration of the existing Skatepark into the new facilities;
  • the installation of terraces and balconies at various spots along the banks of the Pétrusse;
  • the implementation of a motorable path with a width of 4.50 metres along the watercourse, over the entire length of the valley, and a non-drivable path with a width of 2 to 3 metres, located on the opposite side of the main promenade, near the stream;
  • the redefinition of engineering structures including six new bridges (two motorised structures and four for pedestrians) replacing the existing structures;
  • the reintroduction of fish species through the installation of a fish passage allowing migration between the Alzette and the Pétrusse.

Throughout the duration of the work, access for pedestrians and cyclists is guaranteed and appropriate signage will be put in place to provide information on detours.