An expertise evaluation is given for a management project on the Isere river, upstream and in Grenoble, devoted to reduce the large floods effects when crossing the town. The diagnostic is globally satisfying, but suggests several improvements, and recommends strongly a development and a finalizing of the transitory re-flooding of some adapted plots, solution only just started in the project, and among others by developing the concept of vulnerability wich is largely diversified in the Grésivaudan area.