Numerical modeling of the Gérine river’s widening

The Gérine, a pre-Alpine river and an important tributary of the Sarine, has a non-influenced hydrological regime and natural banks with the exception of certain points, including a 4 km section in Marly (Fribourg). In 2002, for fish migration, rock ramps were added to the weirs, which were notched. In addition, the dams were reinforced and wetlands were created in the undergrowth.  Despite these last ecologically favorable measures, the disruption of the width of the Gérine at Marly and its effects are still present. The objective of the project is to increase the width of the Gérine river in order to eliminate the stabilizing sills while guaranteeing protection against floods. A numerical modeling of the project aims at assessing the flow patterns and the morphodynamics in the widening to optimize the project.