Assessing multi‐temporal river‐floodplain dynamics as baseline for process‐oriented restoration in a large river: the Duero River, Spain

Abstract

The time‐based perspective of river‐floodplain processes plays a key role in understanding its evolution until its present situation and in guiding process‐based river restoration. However, despite the wide range of approaches to eco‐hydromorphological characterization, the analysis of fluvial dynamics and their drivers under a temporal perspective requires more investigation. For the present study, a historical analysis of river‐floodplain dynamics has been undertaken in a study section of the Duero River upstream of Zamora (Spain), within the framework of the DRAINAGE project for the integral management of flood risk. Aerial imagery for the period 1945–2017 was used to create habitat maps that were subsequently intersected to identify trajectories of habitat change (anthropization, changeless, progression, and regression). In addition, a Natural Trajectory Index (NTI) and an Anthropization Ratio (AR) were proposed as a way to assess the balance of natural trajectories (progression vs. regression) and the weight of anthropization versus the sum of natural trajectories, respectively. Results show a system with a high degree of stability and anthropization, and a current imbalance of natural trajectories with a predominance of progression in the ecological succession. Rejuvenation processes have to be reactivated through nature‐based solutions, allowing for more sustainable water management practices. This perspective aims at promoting a more resilient system. The diachronic analysis presented is widely exportable to other river‐floodplain systems as a basis for process‐based restoration practice.