Abstract
Elucidating the links between catchment and channel geomorphic processes helps the understanding of landscape evolution and the geomorphic development of river basins, and then the land degradation processes. In this study, we analyse suspended sediment dynamics and its relationship with rainfall, discharge and in-channel sediment storage in a highly dynamic Mediterranean montane catchment (the River Isáben, Southern Pyrenees, NE Iberian Peninsula). The aim is to assess hydrological controls on and temporal patterns of the suspended sediment load. High loads in this basin occur as a consequence of intense erosion in badlands located in the middle of the catchment. This study focuses on a reach located downstream from the main badland areas, where rainfall, discharge (Q), sediment transport (SSC) and in-channel sediment storage were monitored for a 1-year period. Marked seasonality in water and sediment load was observed; whereas most of the discharge occurred in winter and spring, most of the sediment was transported during summer and autumn. Q-SSC hysteretic loops revealed the importance of sediment availability (whether stored in the channel or originating from wider catchment source areas) in the river's sedimentary response. Clockwise loops dominated during winter and spring, whereas counter-clockwise loops occurred mostly in summer and autumn, when in-channel storage reached its maximum. There were significant correlations between rainfall intensity in the sediment source areas, in-channel sediment storage and sediment yield. These correlations emphasize the importance of understanding sediment availability when analysing the temporal dynamics of sediment transport, especially in catchments where different source areas (slopes and riverbed) may contribute to the load to differing degrees and at different times of the year.
| Original language | English |
|---|---|
| Pages (from-to) | 1045–1063 |
| Number of pages | 19 |
| Journal | Land Degradation & Development |
| Volume | 27 |
| Issue number | 4 |
| Early online date | 11 Mar 2015 |
| DOIs | |
| Publication status | Published - May 2016 |
Bibliographical note
We are deeply thankful to the members of the RIUS team (Fluvial Dynamics Research Group, University of Lleida, www.fluvialdynamics.com) for the valuable help during fieldwork. We are also thankful to Till Francke for providing the model codes and for the useful and prompt responses. The second author has a Ramon y Cajal Fellowship (RYC-2010-06264) funded by the Spanish Ministry of Science and Innovation. Special thanks are due to the Ebro Water Authorities for providing the rainfall data and issuing permissions to install the equipment. Part of this work has been undertaken within the framework of the research project Consolider Ingenio 2010 CSD2009-00065 funded by the Spanish Ministry of Economy and Competitiveness. Authors also acknowledge the support from the Economy and Knowledge Department of the Catalan Government through the Consolidated Research Groups 2014 SGR 645 (RIUS–Fluvial Dynamics Research Group) and 2014 SGR 291 (Catalan Institute for Water Research).1Keywords
- sediment transport
- sediment load
- badlands
- hysteresis
- in-channel storage
- River Isabena
- Southern Pyrenees
- Mediterranean basin
