Dimensionless morphological ratios versus stream power variations at bankfull stage in an ephemeral channel

Conesa-García, Carmelo; Pérez‐Cutillas, Pedro; García-Lorenzo, Rafael; Eekhout, Joris; Gutiérrez, Álvaro Gómez; Millares, Agustín; Martínez-Salvador, Alberto

doi:10.1016/j.geomorph.2020.107199

Cited by 7 publications

(20 citation statements)

References 37 publications

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“…In the second case, downstream narrowing, the major event caused significant variations in the topography of the bed, creating new active bars that later, in the event of September 2019, were partially or totally destroyed. These morphological adjustments must have been caused by high stream power values concentrated in short distances, as already suggested by Conesa-García et al [59] for entrenched channel cross-sections, along stretches with sudden changes in bed roughness. This pattern has been found to be linked to channel degradation in semi-arid ephemeral streams (e.g., [35,56]).…”

Section: Morphological Bed Adjustments Observed In Rcr From Tls Datamentioning

confidence: 56%

Combining SfM Photogrammetry and Terrestrial Laser Scanning to Assess Event-Scale Sediment Budgets along a Gravel-Bed Ephemeral Stream

et al. 2020

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Stream power represents the rate of energy expenditure along a stream reach and can be calculated using topographic data acquired via structure-from-motion (SfM) photogrammetry and terrestrial laser scanning (TLS). This study sought to quantitatively relate morphological adjustments in the Azohía Rambla, a gravel-bed ephemeral stream in southeastern Spain, to stream power (ω), critical power (ωc), and energy gradients (∂ω/∂s), along different reference channel reaches of 200 to 300 m in length. High-resolution digital terrain models (HRDTMs), combined with ortophotographs and point clouds from 2018, 2019, and 2020, and ground-based surveys, were used to estimate the spatial variability of morphological sediment budgets and to assess channel bed mobility during the study period at different spatial scales: reference channel reaches (RCRs), pilot bed survey areas (PBSAs), and representative geomorphic units (RGUs). The optimized complementary role of the SfM technique and terrestrial laser scanning allowed the generation of accurate and reliable HRDTMs, upon which a 1-D hydrodynamic model was calibrated and sediment budgets calculated. The resulting high-resolution maps allowed a spatially explicit analysis of stream power and transport efficiency in relation to volumes of erosion and deposition in the RCR and PBSA. In addition, net incision or downcutting and vertical sedimentary accretion were monitored for each flood event in relation to bedforms and hydraulic variables. Sediment sources and sinks and bed armoring processes showed different trends according to the critical energy and stream power gradient, which were verified from field observations. During flows exceeding bankfull discharges (between 18 and 24 m3s−1 according to channel reach), significant variations in ∂ω/∂s values and ω/ωc ratios (e.g., −15< ∂ω/∂s <15 Wm−3; ω/ωc >2 for a peak discharge of 31 m3s−1) were associated with a large amount of bedload mobilized upstream and vertical accretion along the middle reach (average rise height of 0.20 to 0.35 m for the same event). By contrast, more moderate peak flows (≤10 m3s−1) only produced minor changes resulting in surface washing, selective transport, and local bed scouring.

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Section: Morphological Bed Adjustments Observed In Rcr From Tls Datamentioning

confidence: 56%

Combining SfM Photogrammetry and Terrestrial Laser Scanning to Assess Event-Scale Sediment Budgets along a Gravel-Bed Ephemeral Stream

et al. 2020

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“…In the second case, downstream narrowing, the major event caused significant variations in the topography of the bed, creating new active bars that later, in the event of September 2019, were partially or totally destroyed. These morphological adjustments must have been caused by high stream power values concentrated in short distances -as already suggested by Conesa-García et al (Conesa-García et al, 2020) for entrenched channel cross-sectionsalong stretches with sudden changes in bed roughness. This pattern has been found to be linked to channel degradation in semi-arid ephemeral streams (e.g., ).…”

Section: Morphological Bed Adjustments Observed In Rcr From Tls Datamentioning

confidence: 59%

“…Mediterranean ephemeral streams are particularly sensitive to short-term climatic changes, and the impacts related to human activities may affect the degree of response of them (Conesa-García et al, 2020). Heavy rainfalls can produce large volumes of torrential runoff and therefore an increase in the energy load in the transport of sediments.…”

Section: Ephemeral Streamsmentioning

confidence: 99%

“…Ephemeral streams are watercourses in arid and semi-arid environments with unstable morphology and high temporal variability of runoff. The episodes of sudden and extreme discharges that are isolated in time alternate with long periods of drought (Conesa-García et al, 2020). These types of currents are particularly sensitive to shortterm climatic changes, and human impacts can alter their degree of response, sometimes leading to large morphological adjustments during flash floods .…”

Section: Introductionmentioning

confidence: 99%

“…proposed a non-metric multidimensional scale ordering, based on geometric and hydraulic variables: width-to-depth ratio (W/D), stream gradient (S), stream power (Ω), and shear stress (τ). Other authors related morphological adjustments in EGBSs to systematic changes in the mean stream power (ω) / resisting power (ωc) ratio (ω/ωc) (Bull, 1997), and hence in the transport efficiency, associated with the mean stream power gradient (∂ω/∂s) and excess energy (Conesa-García et al, 2020b). Nor are there many studies aimed at evaluating these morphological changes in relation to erosion volumes, deposition, and sediment transport (sediment budgets) on a detailed scale.…”

Section: Introductionmentioning

confidence: 99%

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Remote Sensing and UAVs for the Geomorphological and Habitat Analysis in Ephemeral and Permanent Mediterranean Streams

Mengual¹,

Antonio²

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Assessing current and future available resources to supply urban water demands using a high-resolution SWAT model coupled with recurrent neural networks and validated through the SIMPA model in karstic Mediterranean environments

Jodar-Abellan,

Pardo,

Asadollah

et al. 2024

Environ Sci Pollut Res

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Hydrological simulation in karstic areas is a hard task due to the intrinsic intricacy of these environments and the common lack of data related to their geometry. Hydrological dynamics of karstic sites in Mediterranean semiarid regions are difficult to be modelled mathematically owing to the existence of short wet episodes and long dry periods. In this paper, the suitability of an open-source SWAT method was checked to estimate the comportment of a karstic catchment in a Mediterranean semiarid domain (southeast of Spain), which wet and dry periods were evaluated using box-whisker plots and self-developed wavelet test. A novel expression of the Nash–Sutcliffe index for arid areas (ANSE) was considered through the calibration and validation of SWAT. Both steps were completed with 20- and 10-year discharge records of stream (1996–2015 to calibrate the model as this period depicts minimum gaps and 1985–1995 to validate it). Further, SWAT assessments were made with records of groundwater discharge and relating SWAT outputs with the SIMPA method, the Spain’s national hydrological tool. These methods, along with recurrent neural network algorithms, were utilised to examine current and predicted water resources available to supply urban demands considering also groundwater abstractions from aquifers and the related exploitation index. According to the results, SWAT achieved a “very good” statistical performance (with ANSE of 0.96 and 0.78 in calibration and validation). Spatial distributions of the main hydrological processes, as surface runoff, evapotranspiration and aquifer recharge, were studied with SWAT and SIMPA obtaining similar results over the period with registers (1980–2016). During this period, the decreasing trend of rainfalls, characterised by short wet periods and long dry periods, has generated a progressive reduction of groundwater recharge. According to algorithms prediction (until 2050), this declining trend will continue reducing groundwater available to meet urban demands and increasing the exploitation index of aquifers. These results offer valuable information to authorities for assessing water accessibility and to provide water demands in karstic areas.

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Dimensionless morphological ratios versus stream power variations at bankfull stage in an ephemeral channel

Cited by 7 publications

References 37 publications

Combining SfM Photogrammetry and Terrestrial Laser Scanning to Assess Event-Scale Sediment Budgets along a Gravel-Bed Ephemeral Stream

Combining SfM Photogrammetry and Terrestrial Laser Scanning to Assess Event-Scale Sediment Budgets along a Gravel-Bed Ephemeral Stream

Remote Sensing and UAVs for the Geomorphological and Habitat Analysis in Ephemeral and Permanent Mediterranean Streams

Assessing current and future available resources to supply urban water demands using a high-resolution SWAT model coupled with recurrent neural networks and validated through the SIMPA model in karstic Mediterranean environments

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