Topic
Stream power
About: Stream power is a research topic. Over the lifetime, 1135 publications have been published within this topic receiving 51324 citations.
Papers published on a yearly basis
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TL;DR: In this paper, the predictive power of 10 bed load formulae against bed load rates obtained for a large regulated river (River Ebro) the armor layer of which is subject to repeated cycles of break-up and reestablishment was tested.
29 citations
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TL;DR: In this article, the authors artificially triggered neck cutoffs by excavating a 04m (width) 1.5m (depth) ditch to connect the beginning and ending of two highly convoluted bends along a meandering tributary of the upper Black River, a major tributial of the Upper Yellow River situated in the northeastern side of the Qinghai-Tibet Plateau in China.
Abstract: Neck cutoff is an essential process that significantly changes the morphodynamic characteristics of a meandering bend In reality, however, observing natural processes of a neck cutoff is very difficult In this study, we artificially triggered neck cutoffs by excavating a 04 m (width) × 05 m (depth) ditch to connect the beginning and ending of two highly convoluted bends along a meandering tributary of the upper Black River, a major tributary of the Upper Yellow River situated in the northeastern side of the Qinghai-Tibet Plateau in China Our morphologic and hydraulic measurements in summers of 2013, 2014, 2016, and 2017, the subsequent hydraulic-geometry analysis, and three-dimensional simulation showed that both artificial ditches expanded fast to the size comparable to the former channel in a three-year period and the oxbow channel was disconnected from the former channel quickly, though sediment supply may be limited in this area The morphological adjustment was featured by (1) distinct temporal trends of the development of the width/depth ratio between the two cutoff channels, (2) different diversion factors of the total discharge to the cutoff channel, and (3) diverse interaction patterns between cutoff and former channels These discrepancies were supported by simulated different three-dimensional velocity distributions in the two cutoff channels, suggesting the importance of the clustered local velocities Comparing these results with those reported in earlier studies showed that besides channel slope, unit stream power, and bank strength, the diversion angle between the cutoff and former channel played an important role in controlling channel adjustment The discrepancy of the adjustment processes between the cutoff channel in this study and those in two previous ones revealed that channel adjustment after neck cutoff behaved differently under different physical settings and require more field-based studies
29 citations
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23 Nov 2018TL;DR: In this article, the authors analyzed the catchment response to the 2014 Emme River flood in terms of channel widening and wood recruitment and deposition, and identified the factors controlling these processes.
Abstract: . On 24 July 2014, an exceptionally large flood (recurrence interval ca.
150 years) caused large-scale inundations, severe overbank sedimentation, and
damage to infrastructure and buildings along the Emme River (central
Switzerland). Widespread lateral bank erosion occurred along the river,
thereby entraining sediment and large wood (LW) from alluvial forest stands.
This work analyzes the catchment response to the flood in terms of channel
widening and LW recruitment and deposition, but also identifies the factors
controlling these processes. We found that hydraulic forces (e.g., stream
power index) or geomorphic variables (e.g., channel width, gradient, valley
confinement), if considered alone, are not sufficient to explain the flood
response. Instead, the spatial variability of channel widening was first driven
by precipitation and secondly by geomorphic variables (e.g., channel width,
gradient, confinement, and forest length). LW recruitment was mainly caused by
channel widening (lateral bank erosion) and thus indirectly driven by
precipitation. In contrast, LW deposition was controlled by channel
morphology (mainly channel gradient and width). However, we also observed
that extending the analysis to the whole upper catchment of the Emme River by
including all the tributaries and not only to the most affected zones
resulted in a different set of significant explanatory or correlated
variables. Our findings highlight the need to continue documenting and
analyzing channel widening after floods at different locations and scales for
a better process understanding. The identification of controlling factors can
also contribute to the identification of critical reaches, which in turn is
crucial for the forecasting and design of sound river basin management
strategies.
29 citations
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TL;DR: In this article, the authors present a novel application of fallout cosmogenic 7Be coupled with a constant initial activity (CIA) sediment aging model to quantitatively assess transitional bed load storage times in bars associated with in-channel obstructions (LWD and boulders).
Abstract: [1] The beneficial ecogeomorphic functions associated with large woody debris (LWD) in fluvial environments are well documented and include positive sediment impacts such as channel margin sequestration, increased substrate heterogeneity, and decreased channel embeddedness, as well as numerous secondary benefits such as nutrient retention and increased habitat heterogeneity. Despite an extensive literature documenting such positive sediment attributes of LWD in forested channels, a quantitative analysis of in-channel sediment storage times associated with channel obstructions has traditionally been difficult to assess. In this study along a 9 km stretch of the Ducktrap River in coastal Maine we present a novel application of fallout cosmogenic 7Be (t1/2 = 53 days) coupled with a constant initial activity (CIA) sediment aging model to quantitatively assess transitional bed load storage times in bars associated with in-channel obstructions (LWD and boulders). We find that reach-scale variability in unit stream power and LWD frequency affect sediment storage times, with transport-limited reaches providing longer-term sediment sequestration (generally > 100 days) associated with in-channel obstructions than supply limited ones (<100 days). Estimates of sediment baraccumulation rates also varied between reaches from 0.2 g cm−2 d−1 in the supply limited reach to 0.7 g cm−2 d−1 in the transport-limited reach. Last, greater frequency of sites, increased sediment volumes and storage times, and naturally viable recruitment mechanisms for LWD in forested channels document its superior ecogeomorphic function when compared to boulders in this study, even in the Ducktrap river, where twentieth century logging has greatly reduced the size, frequency, and geomorphic efficacy of in-channel wood. This study has implications for channel restoration efforts and documents a novel application of 7Be and CIA methodology to constraining transitional bed load storage times in the fluvial environment.
29 citations
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TL;DR: Using historical aerial photographs, optically stimulated luminescence dating of fluvial sediments, and field observations, this article document three avulsions that have occurred in the last 650 years along the lower reaches of the semiarid Tshwane River in northern South Africa.
29 citations