Towards the Application of a River Management Approach Encompassing most Natural Process Drivers : Lessons Learned from Freedom Space for Rivers in Quebec (Canada)

Abstract:

The consensus around the need for a shift in river management approaches to include more natural processes is steadily growing amongst scientists, practitioners and governmental agencies. Not only is this a sound way to increase resilience of fluvial systems and adapt to climate change, but it will likely result in improved water quality and better aquatic habitat. This paper presents the freedom space for rivers approach which we have developed recently in Quebec (Canada) to combine natural processes related to mobility, flooding and riparian wetland connectivity into a single index. The approach was applied to 3 contrasted rivers (de la Roche, Yamaska Sud-Est and Matane) to produce two main levels of freedom space, operating at two time scales: “short” (in geomorphic terms, i.e. < 50 years) and long (floodplain renewal, ranging from several decades to centuries). For each river, a cost-benefit analysis revealed economic benefits over a 50-year period when taking into account ecosystem services. There is now a growing interest within ministries and watershed agencies to implement such a management approach, but also strong inertia and resistance to change, particularly in agricultural watersheds. Our observations reveal that for such a shift in paradigm to operate, hydrogeomorphogical concepts must be better understood by those in charge of managing rivers, which is currently not the case in Quebec. The role of integrating scientific knowledge in the implementation of a freedom space for rivers management scheme will be discussed based on case studies in 3 watersheds: rivière du Nord, Coaticook and Mitis/Neigette. The original approach was applied only to the main branches, however the second phase of the project is also aiming to determine whether the impact of leaving more space for natural rivers to operate would be more beneficial in headwater tributaries than in higher-order reaches.