ABSTRACT
The « Isère Amont » project aims to protect the urbanized areas from a bicentennial flood, from Pontcharra to Grenoble. The key measure is expanding flood areas: the flows, over the 30 -year return period flood, are stored in 16 expanding flood areas representing 3500 ha, named “CIC” or “champ d’inondation controlee”. The expanding flood areas are supplied by spillways, and sometimes by removable floodgates. The draining of these areas is accomplished by agricultural drainage channels. No human action is necessary for this operation. All the agricultural and natural areas of the valley will participate to store floods. This operation is the largest French project of this type currently in progress. 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.
