Development and Application of Numerical Models of Sediment Transport Associated with Dam Removal

Cui, Yantao; Wilcox, Andrew C.

doi:10.1061/9780784408148.ch23

Cited by 41 publications

(52 citation statements)

References 21 publications

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“…A concern for the natural flush sediment routing is the significant impact of sedimentation downstream in a relatively short period after dam removal (e.g. Cui & Wilcox, 2008). For better sedimentation management, it should be best to find an improved way to minimize this kind of geomorphic impact, which could be the control of sediment routing at the dam site.…”

Section: Optimization Of Sediment Releasementioning

confidence: 99%

“…For example, the time series of discharge in 2008 was used as the input hydrograph of the first year. For the rest of the nine year hydrograph, we adopted the selected discharge data records from 1932 to 1997 by Stillwater Science (2000) and Cui & Wilcox (2008). The peak discharge varied from 180.4 m 3 /s in the first year to 390.8 m 3 /s in the 10th year post dam removal.…”

Section: Impact Assessment Of the Marmot Dam Removal In The Sandy Rivermentioning

confidence: 99%

“…Wu-Wang-Jia's formula). By means of an approach similar to that adopted by Cui and Wilcox (2008), a 10-year-long hydrograph measured in the river was selected for the long-term assessment, in which each yearly hydrograph was picked up from a yearly data record. For example, the time series of discharge in 2008 was used as the input hydrograph of the first year.…”

Section: Impact Assessment Of the Marmot Dam Removal In The Sandy Rivermentioning

confidence: 99%

“…As a result, bank erosion and channel widening are important adjustment processes. Even if the dam removal process is gradual, river floodwaters can entrain large amounts of deposited sediment and transport it over the low-head dam (Cui & Wilcox, 2008). Furthermore, the bio-geomorphic impact of dam removal on the riverine environment is long-term and long-range both upstream and downstream (Doyle and Stanley, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…For reservoirs with large sediment deposits, released sediments may significantly change the river morphology in both the reservoir and the downstream channels (e.g. Cui & Wilcox, 2008). If reservoir sediment deposits contain contaminants, sediment release may further exacerbate environmental hazards downstream (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Simulation and control of morphological changes due to dam removal in the Sandy River, Oregon, USA

Ding

Altinakar

2015

Proc. IAHS

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A one-dimensional channel evolution simulation model (CCHE1D) is applied to assess morphological changes in a reach of the Sandy River, Oregon, USA, due to the Marmot Dam removal in 2007. Sediment transport model parameters (e.g. sediment transport capacity, bed roughness coefficient) were calibrated using observed bed changes after the dam removal. The validated model is then applied to assess long-term morphological changes in response to a 10-year hydrograph selected from historical storm water records. The long-term assessment of sedimentation gives a reasonable prediction of morphological changes, expanding erosion in reservoir and growing deposition immediately downstream of the dam site. This prediction result can be used for managing and planning river sedimentation after dam removal. A simulation-based optimization model is also applied to determine the optimal sediment release rates during dam-removal that will minimize the morphological changes in the downstream reaches.

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Section: Optimization Of Sediment Releasementioning

confidence: 99%

Section: Impact Assessment Of the Marmot Dam Removal In The Sandy Rivermentioning

confidence: 99%

Section: Impact Assessment Of the Marmot Dam Removal In The Sandy Rivermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Simulation and control of morphological changes due to dam removal in the Sandy River, Oregon, USA

Ding

Altinakar

2015

Proc. IAHS

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Rapid reservoir erosion, hyperconcentrated flow, and downstream deposition triggered by breaching of 38 m tall Condit Dam, White Salmon River, Washington

Wilcox

O'Connor

Major

2014

J. Geophys. Res. Earth Surf.

131

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Condit Dam on the White Salmon River, Washington, a 38 m high dam impounding a large volume (1.8 million m 3 ) of fine-grained sediment (60% sand, 35% silt and clay, and 5% gravel), was rapidly breached in October 2011. This unique dam decommissioning produced dramatic upstream and downstream geomorphic responses in the hours and weeks following breaching. Blasting a 5 m wide hole into the base of the dam resulted in rapid reservoir drawdown, abruptly releasing~1.6 million m 3 of reservoir water, exposing reservoir sediment to erosion, and triggering mass failures of the thickly accumulated reservoir sediment. Within 90 min of breaching, the reservoir's water and~10% of its sediment had evacuated. At a gauging station 2.3 km downstream, flow increased briefly by 400 m 3 s À1 during passage of the initial pulse of released reservoir water, followed by a highly concentrated flow phase-up to 32% sediment by volume-as landslide-generated slurries from the reservoir moved downstream. This hyperconcentrated flow, analogous to those following volcanic eruptions or large landslides, draped the downstream river with predominantly fine sand. During the ensuing weeks, suspended-sediment concentration declined and sand and gravel bed load derived from continued reservoir erosion aggraded the channel by >1 m at the gauging station, after which the river incised back to near its initial elevation at this site. Within 15 weeks after breaching, over 1 million m 3 of suspended load is estimated to have passed the gauging station, consistent with estimates that >60% of the reservoir's sediment had eroded. This dam removal highlights the influence of interactions among reservoir erosion processes, sediment composition, and style of decommissioning on rate of reservoir erosion and consequent downstream behavior of released sediment.

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Channel evolution after dam removal in a poorly sorted sediment mixture: Experiments and numerical model

Ferrer‐Boix

Vide

Parker

2014

Water Resources Research

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Dam removal is commonly used for river restoration. However, there are still some uncertainties associated with dam removal, mainly related to the sediment transport rates released downstream from the deposit that had previously filled the impoundment. This research studies the physical response to dam removal in the antecedent deposit by answering the following questions: (a) how does an initial channel excavated into the deposit evolve, and (b) what is the time distribution of the material released during the early stages of the process. These goals are achieved by an experimental campaign using a poorly sorted mixture of sediment in the antecedent deposit. The research shows that for the given conditions of our experiments, the rate at which the sediment is released depends on the height of the removed dam, the water discharge and the maximum potential volume of sediment to be eroded. This investigation provides new insights of the width evolution when the sediment is composed of a poorly sorted mixture. This evolution is linked to the bed degradation rates: channel narrows during a rapid incisional phase, and subsequently widens when bed degradation rates decrease. Channel width changes propagate upstream as a convection-like perturbation associated with a kinematic wave starting at the location of the antecedent dam. These features are modeled through a new numerical model accounting for mixtures. More specifically, a set of equations has been derived for the variation of bed elevation, channel bottom width, and bed grain-size distribution, which when solved numerically, describe the observed channel processes.

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Development and Application of Numerical Models of Sediment Transport Associated with Dam Removal

Abstract: Because reservoir sediment deposits behave as large sediment pulses once dams are removed, previous simulations of the evolution of sediment pulses in rivers have provided

Cited by 41 publications

References 21 publications

Simulation and control of morphological changes due to dam removal in the Sandy River, Oregon, USA

Simulation and control of morphological changes due to dam removal in the Sandy River, Oregon, USA

Rapid reservoir erosion, hyperconcentrated flow, and downstream deposition triggered by breaching of 38 m tall Condit Dam, White Salmon River, Washington

Channel evolution after dam removal in a poorly sorted sediment mixture: Experiments and numerical model

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