Assessment of downstream trends in channel gradient, total and specific stream power: a GIS approach

Reinfelds, Ivars; Cohen, Tim J; Batten, Paul; Brierley, Gary

doi:10.1016/j.geomorph.2003.10.003

Cited by 103 publications

(106 citation statements)

References 27 publications

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“…Costa and O'Connor (1995) established relationships between stream power and incision or degradation, and other studies have addressed geomorphic changes and effectiveness, channel stability and planform, and especially channel sensitivity to high-magnitude flood events (Bagnold, 1966;Magilligan, 1992;Costa and O'Connor, 1995;Reinfelds et al, 2004). Most studies relating stream power to channel processes have favoured exploring such relationships with specific stream power, which provides a measure of the rate of energy expenditure per unit area of channel bed (Reinfelds et al, 2004).…”

Section: Significant Peak Flow Parametersmentioning

confidence: 99%

Recent human impacts and change in dynamics and morphology of ephemeral rivers

Ortega

Razola

Garzón

2014

Nat. Hazards Earth Syst. Sci.

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Abstract. Ephemeral streams induce flash-flood events, which cause dramatic morphological changes and impacts on population, mainly because they are intermittent and less predictable. Human pressures on the basin modify load and discharge relationships, inducing dormant instability on the fluvial system that will manifest abruptly during flood events. The flash-flood response of two ephemeral streams affected by load supply modification due to land use changes is discussed in a combination of geomorphic and hydraulic approaches. During the Rivillas flash flood, intensive clearing on the basin led to high rates of sediment flowing into an artificially straightened and inefficient channel. The stream evolved from a sinuous single channel into a shallow braiding occupying the entire width of the valley floor. Misfits and unsteady channel conditions increased velocity, stream power and sediment entrainment capacity and considerably magnified flood damage. Resulting morphosedimentary features revealed a close relationship with the valley floor postflood hydraulic model, and pre-event awareness would have made it possible to predict risk-sensitive areas. In the second case, the Azohía stream, modelling of current pre-flood channel conditions make it possible to determine channel narrowing and entrenchment in the lower alluvial fan stretch. Abandonment of intensive agriculture, basin reforestation and urbanization diminish load contribution and trigger channel incision. This induces an increase in slope and velocity in the bankfull channel, producing renewed erosive energy and thus activating upstream propagation of incision and bank undermining. The absence of water-spreading dynamics on the alluvial fan in favour of confinement in a single channel produces an unstable dynamic in the system, also offering a false sense of stability, as long as no large magnitude floods occur. When modelling flood-prone areas and analysing hydraulic variables, it is important to detect possible anthropic disturbances that may affect basin load budgets in order to anticipate catastrophic consequences resulting from inappropriate fluvial management before the occurrence of an extraordinary event.

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Section: Significant Peak Flow Parametersmentioning

confidence: 99%

Recent human impacts and change in dynamics and morphology of ephemeral rivers

Ortega

Razola

Garzón

2014

Nat. Hazards Earth Syst. Sci.

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“…While other smoother functions, such as moving averages, can also be used, the problem with removing spikes in longitudinal profiles using moving averages is one of information preservation. If the span (or averaging window) is too small, spikes remain, but if the window is too large important geomorphic data are averaged out alongside the spikes -ultimately changing the shape of the longitudinal profile from its fundamental form (Reinfelds et al 2004;Jain et al 2006;. Local regression, with and without weights and robustness (lowess, leoss, rlowess and rloess) can also be utilized.…”

Section: Methodsmentioning

confidence: 99%

Analysis of longitudinal profiles along the eastern margin of the Qinghai-Tibetan Plateau

Aiken

Brierley

2013

J. Mt. Sci.

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Abstract:Resulting from the collision of the Eurasian and Indian plates, the Qinghai-Tibetan Plateau is commonly known as the 'roof of the world'. Collectively the Yarlung Tsangpo, Nu, Lancang, Yangtze, Yalong, and Yellow River basins drain the eastern margin of the plateau. In this paper, we utilize Shuttle Radar Topography Mission elevation data to examine morphometric and relief attributes of these basins to reveal insights into tectonic activity and rates of incision. A robust technique using Matlab is proposed to alleviate errors associated with SRTM data in the derivation of river longitudinal profiles. Convex longitudinal profiles are interpreted to be a product of uplift rates that exceed rates of channel incision along the entire margin of the QinghaiTibetan Plateau. Highest relief towards the south reflects extensive fluvial incision. High relief is also prominent along major active faults. Erosion patterns are related to distance from knickpoints. Highest rates of erosion and incision are evident towards the south, with decreasing values towards the north, suggesting a link between tectonic activity and erosion.

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“…This approach was developed into the 'stream power screening tool' [4,35], a bankfull-level assessment with the purpose of rapidly identifying potential sediment issues along a river network and prioritising reaches for further geomorphological investigation. Similarly, Reinfelds et al [116] and Jain et al [117] illustrated how abrupt changes in channel slope along a watercourse, and therefore discontinuities in power, can be linked to deviations from average rates of sediment transport and storage.…”

Section: Stream Energy Approaches In Fluvial Studies: Underpinning Comentioning

confidence: 98%

“…However, where data are available two problematic areas remain: accuracy where banklines are obscured in images or where scans are unreliably filtered for vegetation [141]; wetted width at the time of survey is merely a snapshot of the geometry and might not represent either the bankfull or a temporally-averaged condition [143]. Similarly, for unsurveyed reaches broad-scale channel slope is measured routinely from longitudinal profiles derived from remotely sensed topography and GIS methods (e.g., [116,120,[159][160][161][162]). …”

Section: Cross-sections and Slopementioning

confidence: 99%

“…The employment of flow duration curves in the energy auditing methodology intrinsic to Equation (7) represents a marked difference with other approaches that use single, representative discharges derived from either regional expressions (e.g., [2,116,120,184]) or broad hydrological models (e.g., [118,123,125]). Indeed, Biron et al [126] considered the weakest area in most stream power mapping approaches to be the single, regional-based estimation of bankfull discharge.…”

Section: Channel Dischargementioning

confidence: 99%

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Quantifying River Channel Stability at the Basin Scale

Soar

Wallerstein

Thorne

2017

Water

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This paper examines the feasibility of a basin-scale scheme for characterising and quantifying river reaches in terms of their geomorphological stability status and potential for morphological adjustment based on auditing stream energy. A River Energy Audit Scheme (REAS) is explored, which involves integrating stream power with flow duration to investigate the downstream distribution of Annual Geomorphic Energy (AGE). This measure represents the average annual energy available with which to perform geomorphological work in reshaping the channel boundary. Changes in AGE between successive reaches might indicate whether adjustments are likely to be led by erosion or deposition at the channel perimeter. A case study of the River Kent in Cumbria, UK, demonstrates that basin-wide application is achievable without excessive field work and data processing. However, in addressing the basin scale, the research found that this is inevitably at the cost of a number of assumptions and limitations, which are discussed herein. Technological advances in remotely sensed data capture, developments in image processing and emerging GIS tools provide the near-term prospect of fully quantifying river channel stability at the basin scale, although as yet not fully realized. Potential applications of this type of approach include system-wide assessment of river channel stability and sensitivity to land-use or climate change, and informing strategic planning for river channel and flood risk management.

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Assessment of downstream trends in channel gradient, total and specific stream power: a GIS approach

Cited by 103 publications

References 27 publications

Recent human impacts and change in dynamics and morphology of ephemeral rivers

Recent human impacts and change in dynamics and morphology of ephemeral rivers

Analysis of longitudinal profiles along the eastern margin of the Qinghai-Tibetan Plateau

Quantifying River Channel Stability at the Basin Scale

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