ABSTRACT
The « Isère Amont » project is based on the implementation of « expanding flood areas »» all along the 50 km long Isère valley and aims to protect the urbanized areas from a bicentennial flood, from Pontcharra to Grenoble. The project launched in the early 2012 is worth 112 million euros. A first construction phase extends to 2016 for the downstream 10 km of river, and costs 52 million euros. The first hydraulic works consisted in decreasing gravel banks and partially clearing the vegetation to improve the water-carrying capacity and facilitate the transit of sands and gravels up to deposit areas. Afterwards material extractions occurred to settle two deposit areas. Different types of materials were extracted:
Silty materials, or fine sands, reused to fill ponds;
Gravelly materials, stored and reused to achieve levees confortments;
Materials infested with invasive and other kinds of wastes.
