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16 páginas, 7 figuras, 4 tablas.-- El documento en word es la versión post-print. ; The hydroperiod, flooded sediments and riparian understory were examined for eight riparian wetlands of one Ebro River reach (NE Spain) to relate river-floodplain interactions at different spatio-temporal scales with wetland strucuture. This analysis served as a basis for assessing the ecological status of the study reach and proposing a valid restoration plan. A comparison of water-level fluctuations in riparian wetlands with that in the river channel during an ordinary flood was use to characterize the hydroperiod. This characterization was further linked with the results of a multivariate analysis performed using sediment physico-chemistry. Moreover, different measures of understory diversity were used to estimate the successional stage of eight riparian wetlands located in the same reach of the Ebro River. We described four hydroperiod types from the examined flood, from disconnected oxbow lakes to backflow channels fluctuating in concert with the Ebro River. Also three types of sediment differ in their organic matter content. Both results were closely related reflecting the dominance of endogenous or allogeneous processes. However, such heterogeneity was interpreted as being variable over longer spatiotemporal scales. In addition, the riverscape was found to be homogenous and dominated by wetlands at mature successional stages. Consequently, the lack of erosive floods within the reach seems to make inclusion of ecological restoration of geomorphological dynamics a highly appropriate management objective. Alternative strategies at both reach and site scales are proposed. ; Field and lab work were funded by theDepartment of Environmental Science, Technology and University- Aragon government (Research group E-61 on Ecological Restoration)- and MEC (CGL2005– 07059). The I3P progam from the Spanish research council (CSIC), financed by European Social Funds (UE) granted to Alvaro Cabezas. ; Peer reviewed

It is recognised that the hydrological and erosion processes in watersheds are very much conditioned by the (inter)action of a number of variables. This paper covers a 15-year period of studying those factors that have a major influence on the sediment yield and transport during individual hydrological events in a small Mediterranean agricultural watershed. Multivariate statistical techniques such as cluster analysis and principal component analysis were applied for the interpretation of datasets. In addition, the relationships between suspended sediment concentration and discharge (hysteretic loops) were also analysed. The hydrological response of the studied watershed is mainly controlled by the antecedent condition of the flow. Most of the runoff and sediment are generated during the wet season when vegetation cover is scant and saturation overland flow occurs promptly as a response to almost any rainfall events. In contrast, during the dry seasons even if high-intensity rainfalls normally occur, very scant runoffs are, however recorded, at the exit of the watershed. Most of the eroded sediment seems to come from riparian areas. The discharge registered at the watershed outlet up to 1 h prior to the flood is a very good surrogate for antecedent soil moisture. ; This study was partly funded by the Spanish Government's National Scientific Research, Development and Technological Innovation Plan, both project code CGL2007-63453 and project code CGL2011-24336. The authors also acknowledge the generous contribution of the Department of Rural Development and Environment of the Government of Navarre (Spain).

Dams and impoundments constructed in rivers produce changes in their hydrological and sediment transport regimes, regulate their flows and reduce the supply of sediments downstream. Artificially inducing floods from reservoirs in conjunction with sediment-replenishment strategies is currently being employed to enhance sediment supply to river catchment areas. In this study, sediment-replenished artificial floods are compared to their non-sediment replenishment counterparts. The hysteretic loops between suspended sediment concentration and water flow present low normalized hysteresis indices (close to zero) in the sediment-replenished artificial flood events. In the current work, sediment-replenishment produced a balanced suspended sediment transport in contrast to the without sediment-replenishment cases. The normalized hysteresis indices varied between the different particle sizes studied and the same water flow, indicating that different types of particles are transported differently despite being in the same water flow. Furthermore, both the suspended sediment transport and the sedimentation rate of particles during the flood events was greater for the sediment replenishment cases than for the non-sediment-replenishment cases. All things considered, sediment-replenished artificial flooding provides a successful management strategy for a more balanced suspended sediment transport that could be used as a river restoration practice ; This research was funded by LABAQUA S.A. (Madrid, Spain). We are also grateful for the support given by the Agència Catalana de l'Aigua (ACA Barcelona, Spain) and Serbaikal Ingenieros S.L.L. (Madrid, Spain). This research was funded by the Ministerio de Economía, Industria y Competitividad of the Spanish Government through the grant CGL2017-86515-P. Open Access funding was provided thanks to the CRUE-CSIC agreement with Elsevier