The site of Grangettes, registered as a natural reserve of national and international importance for waterfowl and migratory birds, is the last part of the Swiss lakeshore of Lake Geneva that remains natural. Because of repetitive localized dredging activities of the shoreline since the last century, a severe withdraw of the coastline and its associated natural values has been observed between 1964 and 2001 close to the « Gros Brasset » dredge pit.
To prevent further erosion and even to reconstruct part of the shoreline, erosion mitigation measures have been numerically modelled, optimized, applied and monitored by the cantonal authorities through an evolutive process. Since 8 years, the shoreline bottom has been reconstructed by sediment deposition in critical areas and continuously monitored.
This paper presents the mitigation measures from their initial design to their in-situ application and points out their influence on the waves and sediment transport near the shoreline.
