Channel Restoration Design for Meandering Rivers

Soar, Philip J.; Thorne, Colin R.

doi:10.21236/ada397049

Cited by 149 publications

(146 citation statements)

References 178 publications

(432 reference statements)

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“…Baker and Pickup, 1987). Present day analogues can be seen where pool spacing is adjusted to differing channel width via the discharge-width to meander wavelength relationship (Soar and Thorne, 2001), over channel boundaries of differing resistance. Similarly, the co-location of meander apexes at pools along the lower Suir, represented by the 0.47 ratio of the peak LP cyclicity of 1430 m to median Lm (3050 m), accords with the consensus that pool-spacing approximates Lm/2 (Leopold et al, 1964;Keller and Melhorn, 1978).…”

Section: Preservation Of Bedrock or Coarse Clasticmentioning

confidence: 99%

Eskers in a complete, wet-based glacial system in the Phlegra Montes region, Mars

Gallagher

Balme

2015

Earth and Planetary Science Letters

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This paper investigates the influences of palaeohydrology and geologicaltopographic inheritance in shaping the channel of the lower River Suir, southeast Ireland. Results of acoustic surveys of the lower River Suir and Waterford Harbour reveal two scales of pseudo-cyclic river bedforms. Longitudinal elevation profiles of the geological topography (undulating bedrock and till-mantled bedrock) bounding the present floodplain swath reveal pseudo-cyclicity in that terrain too. Spectral and statistical analyses are used to quantify the cyclicity of the long profile and geological-topographic series. These methods show that the dominant cyclicity of the long profile reflects autocorrelation more than inheritance of cyclicity from the bounding geological topography. The cyclicity of the long profile mainly reflects a hydraulic control on pool-spacing, although some cyclicity probably has been inherited from the geological-topography. Channel-forming palaeodischarge is estimated based on the dominant pool-spacing revealed by spectral analysis, validated using relationships between meander wavelength, channel cross-sectional geometry and hydraulically-informed discharge reconstruction. The palaeodischarge estimates are in close agreement and are two orders of magnitude greater than present flood maxima. Significantly, these palaeodischarge estimates also agree closely with palaeodischarge calculated for the submerged Pleistocene palaeochannel that extends across the near-shore continental shelf from Waterford Harbour. The pool-sequence of the lower Suir and the submerged palaeochannel represent a former land-system that was active during a period of low relative sea level during the last glacial. More broadly, the paper offers insights into the landscape evolution of formerly glaciated regions that experienced very wide This article is protected by copyright. All rights reserved. discharge variability during and after the transition from glacial to interglacial regimes, in a context of complex relative sea level change.

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Section: Preservation Of Bedrock or Coarse Clasticmentioning

confidence: 99%

Eskers in a complete, wet-based glacial system in the Phlegra Montes region, Mars

Gallagher

Balme

2015

Earth and Planetary Science Letters

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“…Restoration is usually intended as "the complete structural and functional return of the river to a predisturbance state" (Cairns, 1991). Soar and Thorne (2001) notice that full-restoration to a pre-disturbance state is an ideal concept. Hence, in the context of this paper, we define river restoration as "the input actions that serve to trigger the fluvial ecosystem evolution toward a new self-sustaining statistical equilibrium (if existing)" (Wohl et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Modern comprehensive approach to monitor the morphodynamic evolution of a restored river corridor

Pasquale

Perona

Schneider

et al. 2011

Hydrol. Earth Syst. Sci.

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Abstract. River restoration has become a common measure to repair anthropogenically-induced alteration of fluvial ecosystems. The inherent complexity of ecohydrologic systems leads to limitations in understanding the response of such systems to restoration over time. Therefore, a significant effort has been dedicated in the recent years worldwide to document the efficiency of restoration actions and to produce new effective guidelines that may help overcoming existing deficiencies. At the same time little attention was paid to illustrate the reasons and the use of certain monitoring and experimental techniques in spite of others, or in relation to the specific ecohydrologic process being investigated. The purpose of this paper is to enrich efforts in this direction by presenting the framework of experimental activities and the related experimental setup that we designed and installed in order to accomplish some of the research tasks of the multidisciplinary scientific project RECORD (Restored Corridor Dynamics). Therein, we studied the morphodynamic evolution of the restored reach of the River Thur near Niederneunforn (Switzerland), also in relation to the role of pioneer vegetation roots in stabilizing the alluvial sediment. In this work we describe the methodology chosen for monitoring the river morphodynamics, the dynamics of riparian and of in-bed vegetation and their mutual interactions, as well as the need of complementing such observations with experiments and with the hydraulic modeling of the site. We also discuss how the designed installation and the experiments Correspondence to: N. Pasquale (nicola.pasquale@ifu.baug.ethz.ch) integrate with the needs of other research groups within the project, in particular providing data for a number of investigations thereby including surface water and groundwater interactions, soil moisture and vegetation dynamics.

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“…Soar and Thorne [19] introduced the CSR concept, using it to analyze the faults in a channel design that led to a failed river restoration project at White Marsh Run, Maryland. It is an extension of the Copeland method developed for the USACE SAM software package [18], and subsequently included in the stable channel design section of HEC-RAS.…”

Section: The Capacity/supply Ratiomentioning

confidence: 99%

“…A more recent approach that aims to improve the physical basis of the Copeland method is the Capacity/Supply Ratio (CSR) method [19]. This approach is analogous to the Copeland method; however, it balances the total sediment delivered from an upstream supply reach through a design reach across the entire flow duration curve (FDC).…”

Section: Introductionmentioning

confidence: 99%

“…The CSR approach can provide a more rigorous analysis of stable channel designs compared to single-discharge methods because it accounts for the influence of geomorphically-effective discharges across the entire FDC, thereby alleviating the uncertainty of selecting and assuming the dominant influence of a single discharge [8]. Although there are still many uncertainties that can arise in the CSR methodology as well, specifically in deriving a representative FDC, this approach nevertheless has the potential to provide a more comprehensive and robust channel design analysis over the single-discharge technique [19].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Full Spectrum Analytical Channel Design with the Capacity/Supply Ratio (CSR)

Stroth¹,

Bledsoe²,

Nelson³

2017

Preprint

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Analytical channel design tools have not advanced appreciably in the last decades, and continue to produce designs based upon a single representative discharge that may not lead to overall sediment continuity. It is beneficial for designers to know when a simplified design may be problematic and to efficiently produce alternative designs that approximate sediment balance over the entire flow regime. The Capacity/Supply Ratio (CSR) approach, an extension of the Copeland method of analytical channel design for sand channels, balances the sediment transport capacity of a design reach with the sediment supply of a stable upstream reach over the entire flow duration curve (FDC) rather than just a single discharge. Although CSR has a stronger physical basis than previous analytical channel design approaches, it has not been adopted in practice because it can be a cumbersome and time-consuming iterative analysis without the use of software. We investigate eighteen sand-bed rivers in a comparison of designs based on the CSR approach and five single-discharge metrics: the effective discharge (Qeff) or discharge that transports the most sediment over time, the 1.5-year recurrence interval discharge (Q1.5), the bankfull discharge (Qbf), and the discharges associated with 50th (Qs50) and 75th (Qs75) percentiles of the cumulative sediment yield curve. To facilitate this analysis we developed a novel design tool using the Visual Basic for Applications (VBA) programming language in Excel ® to produce stable channel slope-width combinations based on the CSR methodology for both sand-and gravel-bed streams. The CSR Stable Channel Design Tool's (CSR Tool) code structure was based on Copeland's method in SAM and HEC-RAS (Hydrologic Engineering Center's River Analysis System) and was tested with a single discharge to verify outputs. The Qs50 and Qs75 single-discharge designs match the CSR output most closely, followed by the Qbf, Qeff, and Q1.5. The Qeff proved to be the most inconsistent design metric because it can be highly dependent on the binning procedure used in the effectiveness analysis. Furthermore, we found that the more rigorous physical basis of the CSR analysis is potentially most important in designing 'labile' channels with highly erodible substrate, high perennial flow 'flashiness,' low width-to-depth ratio, and high incoming sediment load. The CSR Tool provides a resource for river restoration practitioners to efficiently utilize in-depth design techniques that can promote sediment balance in dynamic fluvial systems.

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Channel Restoration Design for Meandering Rivers

Cited by 149 publications

References 178 publications

Eskers in a complete, wet-based glacial system in the Phlegra Montes region, Mars

Eskers in a complete, wet-based glacial system in the Phlegra Montes region, Mars

Modern comprehensive approach to monitor the morphodynamic evolution of a restored river corridor

Full Spectrum Analytical Channel Design with the Capacity/Supply Ratio (CSR)

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