Assessment of channel changes in a Mediterranean ephemeral stream since the early twentieth century. The Rambla de Cervera, eastern Spain

Beltrán, Francisca S. Segura; Ibor, Carles Sanchís

doi:10.1016/j.geomorph.2013.06.021

Cited by 56 publications

(30 citation statements)

References 45 publications

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“…The significance of load discharge for channel incision was pointed out by Segura-Beltrán and Sanchis-Ibor (2013) in a similar Mediterranean ephemeral stream environment. They showed that even when large floods are responsible for transporting high amounts of sediment, channel incision only occurs when there is a supply deficit, similar to what happened in their case study following basin afforestation.…”

Section: Discussionmentioning

confidence: 98%

Towards an increase of flash flood geomorphic effects due to gravel mining and ground subsidence in Nogalte stream (Murcia, SE Spain)

Ortega-Becerril

Garzón

Béjar‐Pizarro

et al. 2016

Nat. Hazards Earth Syst. Sci.

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Abstract. Transition from endorheic alluvial fan environments to well-channelized fluvial systems in natural conditions may occur in response to base-level fluctuations. However, human-induced changes in semi-arid regions can also be responsible for similar unforeseen modifications. Our results confirm that in-channel gravel mining and aquifer overexploitation over the last 50 years in the case study area have changed the natural stability of the Nogalte stream and, as a result, its geomorphic parameters including channel depth and longitudinal profile have begun to adapt to the new situation. Using interferometric synthetic aperture radar (InSAR) data we obtain maximum values for ground subsidence in the Upper Guadalentín Basin of ∼ 10 cm yr −1 for the period 2003-2010. In this context of a lowered base level, the river is changing its natural flood model to a more powerful one. A comparison of the 1973 flood event, the most dramatic flood event ever recorded in the area, with the 2012 event, where there was a similar discharge but a sediment load deficit, reveals greater changes and a new flooding pattern and extension. In-channel gravel mining may be responsible for significant local changes in channel incision and profile. This, together with the collateral effects of aquifer overexploitation, can favour increased river velocity and stream power, which intensify the consequences of the flooding. The results obtained here clearly demonstrate an existing transition from the former alluvial pattern to a confined fluvial trend, which may become more pronounced in the future due to the time lag between the drop in aquifer level and ground subsidence, and introduce a new scenario to be taken into consideration in future natural hazard planning in this area.

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Section: Discussionmentioning

confidence: 98%

Towards an increase of flash flood geomorphic effects due to gravel mining and ground subsidence in Nogalte stream (Murcia, SE Spain)

Ortega-Becerril

Garzón

Béjar‐Pizarro

et al. 2016

Nat. Hazards Earth Syst. Sci.

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“…Due to the high infiltration and sporadic nature of rain events, only intensive rains, i.e. a run-off threshold of 65 mm, cause flow in the river corridor (Segura-Beltrán and Sanchis-Ibor, 2013). This run-off threshold may vary between seasons, due to soil moisture and the frequency of rains.…”

Section: Introductionmentioning

confidence: 99%

Topographical changes caused by moderate and small floods in a gravelly ephemeral river – 2D morphodynamic simulation approach

Lotsari

Calle

Benito

et al. 2017

Preprint

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Abstract. In ephemeral rivers, channel morphology represents a snapshot at the end of a succession of geomorphic changes performed by a flood. In most cases, the channel shape and bedform evolution during different phases of a flood hydrograph 15 are not recognized from field evidence. This paper analyzes the capabilities of morphodynamic modelling (Delft 2D) for resolving the evolution of a gravelly ephemeral river channel during consecutive, moderate-and low-magnitude discharge events. We pursue for schematic concepts for simulations in ephemeral gravely rivers that provide an outcome with the closest similarity to the post-flood reality. Based on the simulations, we analyze the morphodynamic evolution of Rambla de la Viuda The spatially varying grain size data and transport equations were the most important factors, in addition to the quality of recorded discharge, for the simulation results of the channel evolution. The total load equation worked better, compared to the 25 deterministic equation. The erosion and deposition can be in total greater during the long-lasting receding phase than during the rising phase. The deposition and erosion peaks are predicted to occur at the beginning of the moderate-magnitude discharge event, whereas deposition dominates throughout the event. On the contrary, the low-magnitude discharge event only experiences the peak of channel changes after the discharge peak. These different predicted erosion/deposition patterns suggest a hysteresis effect on the morphodynamic changes, and stress the importance of previous flood history (timing, succession and 30 magnitude) in understanding the geomorphic response of gravelly ephemeral rivers.Earth Surf. Dynam. Discuss., https://doi

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“…The latter is commonly dominated by coarse fractions (gravels and boulders) (Gómez, 1987), which indicates high-energy environments and the relatively easy access of sediment from hillslopes to channels (Leopold, 1994). Such rivers show extremely large spatial variability in sedimentary features and rapid responses to upstream changes, including the construction of check-dams and land cover changes (Brooks and Brierley, 1997;Kondolf et al, 2002;Marston et al, 2003;Liébault et al, 2005;Boix-Fayos et al, 2007;Keesstra, 2007;García-Ruiz and Lana-Renault, 2011;Segura-Beltrán and Sanchis-Ibor, 2013). Torrential rivers, or torrents, are particular types of mountain rivers, with longitudinal gradients >5%, unstable geological formations, and sediment dominated by boulders and blocks that enter the streambed mainly through debris flows and landslides (Rickenmann, 1997;Benda et al, 2005;D'Agostino, 2013;Picco et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Organización y ajuste de sedimentos en un tramo torrencial de la cabecera del río Ijuez, Pirineo central español

Gómez-Villar

Sanjuán

García‐Ruiz

et al. 2014

CIG

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Assessment of channel changes in a Mediterranean ephemeral stream since the early twentieth century. The Rambla de Cervera, eastern Spain

Cited by 56 publications

References 45 publications

Towards an increase of flash flood geomorphic effects due to gravel mining and ground subsidence in Nogalte stream (Murcia, SE Spain)

Towards an increase of flash flood geomorphic effects due to gravel mining and ground subsidence in Nogalte stream (Murcia, SE Spain)

Topographical changes caused by moderate and small floods in a gravelly ephemeral river – 2D morphodynamic simulation approach

Organización y ajuste de sedimentos en un tramo torrencial de la cabecera del río Ijuez, Pirineo central español

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