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The relation between rainfall, runoff, erosion and sediment transport is highly variable in Mediterranean catchments. Their relation can be modified by land use changes and climate oscillations that, ultimately, will control water and sediment yields. This paper analyses rainfall, runoff and sediment transport relations in a meso-scale Mediterranean mountain catchment, the Ribera Salada (NE Iberian Peninsula). A total of 73 floods recorded between November 2005 and November 2008 at the Inglabaga Sediment Transport Station (114.5 km2) have been analysed. Suspended sediment transport and flow discharge were measured continuously. Rainfall data was obtained by means of direct rain gauges and daily rainfall reconstructions from radar information. Results indicate that the annual sediment yield (2.3 t km− 1 y− 1 on average) and the flood-based runoff coefficients (4.1% on average) are low. The Ribera Salada presents a low geomorphological and hydrological activity compared with other Mediterranean mountain catchments. Pearson correlations between rainfall, runoff and sediment transport variables were obtained. The hydrological response of the catchment is controlled by the base flows. The magnitude of suspended sediment concentrations is largely correlated with flood magnitude, while sediment load is correlated with the amount of direct runoff. Multivariate analysis shows that total suspended load can be predicted by integrating rainfall and runoff variables. The total direct runoff is the variable with more weight in the equation. Finally, three main hydro-sedimentary phases within the hydrological year are defined in this catchment: (a) Winter, where the catchment produces only water and very little sediment; (b) Spring, where the majority of water and sediment is produced; and (c) Summer–Autumn, when little runoff is produced but significant amount of sediments is exported out of the catchment. Results show as land use and climate change may have an important role in modifying the cycles of water and sediment yields in Mediterranean mountain catchments. ; This work was performed in the framework of research agreement between the Catalan Water Agency and the Forest Sciences Centre of Catalonia to study 'Fluvial dynamics in river basins of the Segre-Ebro in Catalonia', and within the projects CGL2009-09770/BTE and Consolider Ingenio 2010 SCARCE CSD2009-00065, financed by the Ministry of Economy and Competitiveness, and SESAM-1&2 funded by the DFG Deutsche Forschungsgemeinschaft BR 1731/11-1 & BR 1731/11-2. The study has benefited from data analysis methodology developed in the MORPHSED project, funded by the Ministry of Economy and Competitiveness and European FEDER funds (CGL2012-3639). The second author has a research contract funded by the Ramón y Cajal Program (RYC-2010-06264) with Human Capital Attraction Programme funded by funded by the Ministry of Economy and Competitiveness. Authors acknowledge the support from the Economy and Knowledge Department of the Catalan Government through the Consolidated Research Groups: RIUS -Fluvial Dynamics Research Group (2014-SGR-645).

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

AbstractUsing the finite volume method, a 2‐D water‐sediment coupled model was developed to investigate the transport mechanisms of water and sediment in Poyang Lake, the largest river‐connected lake in China. Simulating water and sediment transport processes in an average water year revealed that the total volume of water and the amount of suspended sediment transported from the five main rivers upstream of Poyang Lake were approximately 1.56 × 1011 m3 and 1.25 × 107 t, respectively. The outputs of water and sediment from the lake to the downstream Yangtze River were approximately 2.17 × 1011 m3 and 1.53 × 107 t, respectively. During the wet season, especially between July and September, nearly 1.06 × 1010 m3 of water and 1.89 × 106 t of suspended sediment were transported upstream from the Yangtze River into the lake due to the high external water levels, which accounted for 4.88% and 12.35%, respectively, of the total annual transport from the lake into the Yangtze River.

A common approach used to mitigate riverbank erosion and maintain watercourse alignments has been through the application of riprap or larger, more stable particles to channel boundaries along reaches of interest. However, very often, these large particles become dislodged from their intended locations (failed erosion measures), becoming part of the bed material composition. In natural systems, large immobile sediments or boulders can also be found, which are often sourced from glacial erratics or colluvial inputs with different spacing and arrangements among them. In lower gradient gravel-bed channels, the impacts that large clasts may impart on river morphologies are uncertain and are studied in this paper. This paper utilizes laboratory experiments to evaluate the effects that varying spacing of large immobile particles in a gravel-bed channel have on sediment transport and bed morphology. The laboratory experiments consist of a series of test cases with a varying spacing of large immobile particles and one base case with no large immobile particles present. In each case, the flume bed was composed of a poorly sorted gravel mixture with a bimodal distribution of sand and gravel meant to be representative of a natural gravel-bed channel. The results of the test cases demonstrated that at a low spacing of large immobile particles, the transported material and the bed material both became coarser. At a medium spacing of large immobile particles, the bed material size and erosion reached a maximum, and the coarser bed material was transported at approximately the same rate as the finer material. Finally, at a high spacing of large immobile particles, the size of the transported material and bed material sizes were similar to that of the base case, and the sediment transport also had the strongest clockwise hysteresis trend, which ultimately led to a net erosion of the gravel-bed channel. ; This projectwas supported by funding from an NSERC IPS (McKie), by the H2020-MSCA-IF-2018 programme (Marie Sklodowska-Curie Actions) of the European Union under REA grant agreement number 834329-SEDILAND (Juez) and by Water Regime Investigations and Simulations Ltd., JTB Environmental Systems Inc. and R&M Construction (Plumb). ; Peer reviewed

Antea Group and KULeuven were awarded a project in Flanders to identify the regions exporting high sediment loads to unnavigable watercourses and the sedimentation zones within them. Two types of models are applied: hydrological sediment export models (SEM) and hydraulic sediment transport models (STM). The influence of erosion control measures on sediment export as well as river engineering measures needs to be taken into account. A concept will be developed to connect the SEM and STM, enabling the sediment to be routed from upstream to the sedimentation zones. Results of the study will be used by the Flemish government to plan erosion control measures, estimate future sedimentation volumes, steer sedimentation and optimize river engineering and dredging works. Finally, model results could also be used to obtain better insights to the re-suspension risks of contaminated sediment in watercourses.

Antea Group and KULeuven were awarded a project in Flanders to identify the regions exporting high sediment loads to unnavigable watercourses and the sedimentation zones within them. Two types of models are applied: hydrological sediment export models (SEM) and hydraulic sediment transport models (STM). The influence of erosion control measures on sediment export as well as river engineering measures needs to be taken into account. A concept will be developed to connect the SEM and STM, enabling the sediment to be routed from upstream to the sedimentation zones. Results of the study will be used by the Flemish government to plan erosion control measures, estimate future sedimentation volumes, steer sedimentation and optimize river engineering and dredging works. Finally, model results could also be used to obtain better insights to the re-suspension risks of contaminated sediment in watercourses.

This study involves an assessment of various artificial intelligence-related techniques which aim to produce a more robust system for sediment transport modeling. The intelligent systems developed in this research are directly applicable to academic knowledge and use data from a report on "water circulation assessment in the "Linguado" Channel and Babitonga Bay ,"Santa Catarina", Brazil, developed by Military Engineering Institute (IME). The solution employed for sediment transport was built using an intelligent system from the conception of two hybrid models. The first was a Neuro-Fuzzy (ANFIS) hybrid model for the study of hydrodynamic behavior, aiming to determine flow rate in the channel. The second was a fuzzy genetic model, able to assess sediment transport in the "Linguado" Channel. The study's conclusion compares the different effects involved in the dredging equilibrium in the "Linguado" Channel according to this hybrid model with the results obtained using a finite element model in the MIKE21® software.

Soil erosion by rain and surface runoff is an important problem in the Mediterranean countries. The study of the relationship between erosion and sediment transport with hydrological and climatic factors have been conducted in many countries around the world. The aim of this work is to show rainfall impact on the variability of spatial and temporal concentration in twelve drainage basins in the west of Algeria. We will also seek to find a representative parameter of rainfall erosive potential on a Time and spatial scale. When studying sediment transport in twelve drainage basins of the Centre and the west of Algeria, we have found that the modified Fournier index Which explains much of the specific degradation compared to the Fournier index. The study of the temporal variability of the annual rainfall series, modified Fournier index and concentration of the precipitation in the year for a series from 1930 to 2007 showed a negative trend of the two variables. The annual rainfall and modified Fournier index have declined by more than 20%. This decline is more significant in inland areas.