After major floods occurred in 2003 on the Rhône River (France), the State and local authorities created a new institution at river level, in order to tackle flood issues at a supposedly more functional scale. Called Plan Rhône, this new partnership combined several policy sectors and several administrative levels, with the aim of developing the river territory and preserving floodplain retention capacity. The plan included a floodplain restoration project. However, after five years of negotiation, the project was finally abandoned. In this article, we analyze the drivers behind the failure to preserve floodplain retention capacity by focusing on scale issues, using two theoretical frameworks: the concept of "functional fit" between the scale of ecological issues and that of the institutions in charge of those issues, and the concept of "politics of scale" in which scale results from historical processes. We conclude that the scaling of an issue results from history. It legitimates a specific point of view and hampers alternative ways of seeing reality at other scales.

International audienceFloodplain restoration projects are part of sustainable flood management model. However, in practice, they are rarely implemented. We analyze the failure of a floodplain restoration project that was supposed to be implemented on the River Rhône (France). Based on the analysis of floodplain restoration projects implementation literature, we identified several constraints on the implementation of the project. In accordance with the literature, institutional factors were found to have played a critical role in the failure of the project. Other factors such as opposing representations between inhabitants and river managers were also important. Moreover, the strong involvement of the State alongside river managers proved to be a major constraint on implementation

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São Paulo metropolitan region experienced an acute water crisis between 2013 and 2015. According to the Brazilian and international press, it was due to climatic, anthropogenic, and water management factors. This paper assesses the hydro-climatic characteristics of the crisis by focusing on the Alto-Tietê basin and the headwater of the Piracicaba-Capivari-Jundiaí (PCJ) basin that supply 70% of the water consumed in the metropolis. Based on 16 rain-gauge stations, 5 runoff-gauge stations, and several statistical analyses carried over the 1951-2015 period, this assessment shows that the 2013-2015 hydro-climatic crisis resulted from a large number of days without rain in the north of the Alto-Tietê basin and to less intense precipitation events in the headwaters of the PCJ basin during the austral spring 2013 and the year 2014. It also defines a return period of 98 years for observed river flows in 2014. Despite the rare nature of this hydrological drought, the need for efficient water saving policies is brought forward.