Revitalising the Valangon at Dizy

The project to revitalise the Valangon involves restoring the highly damaged river to its  ecomorphological state, partly due to the fact that half of its course was buried.

In the commune of Dizy, the Valangon consists of a buried and piped section of around 400m. The project involved opening up a 460 m stretch of the river.

This section then connects to the current open-cast Valangon route which flows in the Etroz forest. Directly upstream of this connection, 2 ponds are designed into the scheme. These will be fed by the last section of the Valangon pipeline left in place and fed by a few drainage pipes. There is also the possibility of regulating their supply directly from the Valangon.

The project addresses a number of agricultural issues. Areas of riverbank will be restored to arable land, which will require very gentle slopes (< 18%). Soil management will enable the topsoil to be reused on the banks and on another agricultural plot. Four culverts (see Figure 2) will also provide access to the agricultural plot. These were designed in close collaboration with the farmer.

The project also includes the construction of a bridge where the re-opened watercourse crosses the road. This structure is made of reinforced concrete (see Figure 3).

The project also includes a number of network issues, with the relocation of a drinking water pipe and the creation of a supply pipe for drinking troughs.

The banks will be protected entirely by plant-based engineering, with riprap at key points: a culvert upstream of the crossing structures, a bend, etc. The slopes of the banks are diversified to meet the various environmental constraints (locally steep slopes for crayfish, etc.). A small pond and various pools have also been created.

Period: 2018 - 2023

Gruner services:

Hydraulic sizing ;
Call for tenders for the civil engineering works
Execution project for the civil engineering part,
Local works management (DLT) for the civil engineering part,
Supervision of execution in collaboration with Prona Romandie SA
Project management

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