Sediment transport in two mediterranean regulated rivers

  • Mediterranean climate is characterized by highly irregular rainfall patterns with marked differences between wet and dry seasons which lead to highly variable hydrological fluvial regimes. As a result, and in order to ensure water availability and reduce its temporal variability, a high number of large dams were built during the 20th century (more than 3500 located in Mediterranean rivers). Dams modify the flow regime but also interrupt the continuity of sediment transfer along the river network, thereby changing its functioning as an ecosystem. Within this context, the present paper aims to assess the suspended sediment loads and dynamics of two climatically contrasting Mediterranean regulated rivers (i.e. the Esera and Siurana) during a 2-yr period. Key findings indicate that floods were responsible for 92% of the total suspended sediment load in the River Siurana, while this percentage falls to 70% for the Esera, indicating the importance of baseflows on sediment transport in this river. This fact is related to the high sedimentMediterranean climate is characterized by highly irregular rainfall patterns with marked differences between wet and dry seasons which lead to highly variable hydrological fluvial regimes. As a result, and in order to ensure water availability and reduce its temporal variability, a high number of large dams were built during the 20th century (more than 3500 located in Mediterranean rivers). Dams modify the flow regime but also interrupt the continuity of sediment transfer along the river network, thereby changing its functioning as an ecosystem. Within this context, the present paper aims to assess the suspended sediment loads and dynamics of two climatically contrasting Mediterranean regulated rivers (i.e. the Esera and Siurana) during a 2-yr period. Key findings indicate that floods were responsible for 92% of the total suspended sediment load in the River Siurana, while this percentage falls to 70% for the Esera, indicating the importance of baseflows on sediment transport in this river. This fact is related to the high sediment availability, with the Esera acting as a non-supply-limited catchment due to the high productivity of the sources (i.e. badlands). In contrast, the Siurana can be considered a supply-limited system due to its low geomorphic activity and reduced sediment availability, with suspended sediment concentration remaining low even for high magnitude flood events. Reservoirs in both rivers reduce sediment load up to 90%, although total runoff is only reduced in the case of the River Esera. A remarkable fact is the change of the hydrological character of the River Lem downstream for the dam, shifting from a humid mountainous river regime to a quasi-invariable pattern, whereas the Siurana experiences the opposite effect, changing from a flashy Mediterranean river to a more constant flow regime below the dam. (C) 2015 Elsevier B.V. All rights reserved.show moreshow less

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Metadaten
Author:G. Lobera, R. J. Batalla, D. Vericat, José Andrés López-Tarazón, A. Tena
DOI:https://doi.org/10.1016/j.scitotenv.2015.08.018
ISSN:0048-9697
ISSN:1879-1026
Pubmed Id:http://www.ncbi.nlm.nih.gov/pubmed?term=26372613
Parent Title (English):The science of the total environment : an international journal for scientific research into the environment and its relationship with man
Publisher:Elsevier
Place of publication:Amsterdam
Document Type:Article
Language:English
Year of first Publication:2016
Year of Completion:2016
Release Date:2020/03/22
Tag:Barasona Reservoir; Ebro basin; Flow regime; Mediterranean; Sediment load; Siurana Reservoir; Suspended sediment transport
Volume:540
Pagenumber:13
First Page:101
Last Page:113
Funder:Spanish Ministry of Economy and Competitiveness [CSD2009-00065]; Spanish Ministry of Science and Innovation [RYC-2010-06264]; Secretariat for Universities and Research of the Department of the Economy and Knowledge of the Autonomous Government of Catalonia; Economy and Knowledge Department of the Catalan Government through the Consolidated Research Group [2014 SGR 645]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Erd- und Umweltwissenschaften
Peer Review:Referiert