Swiss contractor Subax is using a amphibious dredger to return approximately 14,000 cubic metres of lakebed sand to the eroding shoreline of the Grande Cariçaie nature reserve on Lake Neuchâtel.
The project is led by the Association de la Grande Cariçaie (AGC). It covers about one kilometre of shore at Crevel, between the port of Cheyres and the Crevel residential area, with nourishment extending roughly 30 metres out from the shore.
The dredger, built by Aquamec of Finland, is working approximately 350 metres offshore. It pumps sand from selected extraction areas through a floating pipeline to the placement area, where a separate machine reshapes it.
Subax Director Ludovic Piccand said the dredger's arm can excavate to a maximum depth of 5.4 metres while put the delivery rate is 50 to 80 cubic metres of sand per hour.
The fill forms a gently sloping beach intended to dissipate wave energy. Reed clumps will be planted in February 2027, when the lake level is low, to stabilise the fill and allow reed beds to recolonise the shore.
"The sand that was here has moved offshore,” said AGC Director Michel Baudraz. “We will simply retrieve it offshore and bring it back here, create a gentle slope so that the waves can no longer erode it, and plant reeds on top and rebuild the reed beds."
Waves and wind-driven currents cause local shoreline retreat of up to around one metre per year. Baudraz said the section shelters high-value natural habitats, UNESCO World Heritage archaeological sites, and homes about 50 metres from the water.
The CHF900,000 (US$1.1 million) project is funded by the cantons of Fribourg and Vaud and the Swiss Government. Effectiveness monitoring is planned for at least five years.
AGC would like to extend the method to the roughly 11 kilometres of southern shoreline affected by erosion.