Modeling Benthic Oxygen Uptake by Pumping

Rutherford, James; Boyle, J. D.; Elliott, Alexander H.; Hatherell, T. V. J.; Chiu, T. W.

doi:10.1061/(asce)0733-9372(1995)121:1(84)

Cited by 63 publications

(65 citation statements)

References 11 publications

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“…5.4 Tracer dynamics in a ripple bed Rutherford et al (1995) provide analytical solutions for the penetration and distribution of O 2 in triangular ripple beds imposing a known (measured) pressure distribution as a boundary condition at the ripple interface. We provide similar numerical simulations of tracer transport, where the pressure distribution is now derived from a free flow model above the ripple bed.…”

Section: Tracer Dynamics In a Benthic Chambermentioning

confidence: 99%

“…Typically however, biological and physical aspects have been studied in different research communities. Physical mechanisms have attracted the attention of engineers and physicists, focusing on the waveinduced advection below sand ripples (Shum, 1992) and flow over ripples (Savant et al, 1987;Rutherford et al, 1995;Elliott and Brooks, 1997a). As a result of this, a firm modelling tradition has been established in the engineering literature (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Quantifying biologically and physically induced flow and tracer dynamics in permeable sediments

et al. 2007

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Abstract. Insight in the biogeochemistry and ecology of sandy sediments crucially depends on a quantitative description of pore water flow and the associated transport of various solutes and particles. We show that widely different problems can be modelled by the same flow and tracer equations. The principal difference between model applications concerns the geometry of the sediment-water interface and the pressure conditions that are specified along this boundary. We illustrate this commonality with four different case studies. These include biologically and physically induced pore water flows, as well as simplified laboratory setups versus more complex field-like conditions: [1] lugworm bio-irrigation in laboratory set-up, [2] interaction of bioirrigation and groundwater seepage on a tidal flat, [3] pore water flow induced by rotational stirring in benthic chambers, and [4] pore water flow induced by unidirectional flow over a ripple sequence. The same two example simulations are performed in all four cases: (a) the time-dependent spreading of an inert tracer in the pore water, and (b) the computation of the steady-state distribution of oxygen in the sediment. Overall, our model comparison indicates that model development for sandy sediments is promising, but within an early stage. Clear challenges remain in terms of model development, model validation, and model implementation.

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Section: Tracer Dynamics In a Benthic Chambermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantifying biologically and physically induced flow and tracer dynamics in permeable sediments

et al. 2007

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“…Thus the "pure turnover" case will only occur when pumping is absent or insignificant over the entire subsurface. Examples of pure turnover cases would be bedrock-dominated rivers or isolated sand bars such that practically the entire bed is subject to scour, or rivers with extremely fine sediment such that the pumping velocities are practically zero (an example is given by Rutherford et al [1995]). Pumping might also reasonably be eliminated when a fast-moving tracer The spiral pattern in Figure lb results from the superposition of the periodic flow induced by moving bed forms and the constant effect of the channel slope.…”

Section: Solute Exchangementioning

confidence: 99%

Hyporheic exchange of solutes and colloids with moving bed forms

Packman¹,

Brooks²

2001

Water Resources Research

147

127

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Abstract. Stream-subsurface exchange provides the opportunity for stream-borne substances to interact with streambed sediments in the subsurface hyporheic mixing zone. The downstream transport of both solutes and colloids can be substantially affected by this exchange, with significant implications for contaminant transport and stream ecology. Several previous studies have demonstrated that bed form-induced advective flows (pumping) and scour/deposition of bed sediments (turnover) will often be the dominant processes controlling local exchange with the streambed. A new model is presented for combined turnover and pumping exchange due to relatively fast-moving bed forms, i.e., when turnover dominates the exchange in the upper part of the bed where active bed sediment transport occurs. While turnover rapidly mixes the upper layer of the bed, advective pumping produces exchange with the deeper, unscoured region of the subsurface. The net exchange due to these processes was analyzed using fundamental hydraulic principles: the initial exchange was calculated using an existing geometric model for turnover, and then the later exchange was determined by analyzing the advective flow induced under the moving bed form field. The exchange of colloidal particles due to moving bed forms was also modeled by considering the further effects of particle settling and filtration in the subsurface. Experiments were conducted in a recirculating flume to evaluate solute (conservative Li +) and colloid (kaolinite) exchange with a sand bed. The solute and colloid exchange models performed well for fast-moving bed forms, but underpredicted the colloid exchanges observed with lower rates of bed sediment transport. For very slowly moving bed forms it was found that turnover could be completely neglected, and observed colloid exchanges were represented well by a pure pumping model. In the intermediate case where turnover and pumping rates are similar, water carried into the bed by turnover is immediately released by pumping, and vice versa. Thus, while this work further elucidated the basic processes controlling solute and colloid exchange with a bed covered by bed forms and provided a fundamental model for exchange due to fast-moving bed forms, exchange in the intermediate case where turnover and pumping tend to compete can only be bounded by current models.

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“…Our simple model builds on an idealized flow field for hyporheic exchange first proposed by Elliott and Brooks (hereafter referred to as EB) 12,13 and generalizes a solution for hyporheic exchange and reaction presented by Rutherford et al that focused on benthic oxygen uptake of sediments in a polluted stream. 14 The Elliott and Brooks Model for Pumping Across Bed forms. The EB flow model is premised on the idea that turbulent flow over periodic bed forms causes the dynamic pressure at the sediment−water interface to oscillate with distance downstream.…”

Section: ■ Introductionmentioning

confidence: 99%

First-Order Contaminant Removal in the Hyporheic Zone of Streams: Physical Insights from a Simple Analytical Model

Grant

Stolzenbach

Azizian

et al. 2014

Environ. Sci. Technol.

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A simple analytical model is presented for the removal of stream-borne contaminants by hyporheic exchange across duned or rippled streambeds. The model assumes a steady-state balance between contaminant supply from the stream and first-order reaction in the sediment. Hyporheic exchange occurs by bed form pumping, in which water and contaminants flow into bed forms in highpressure regions (downwelling zones) and out of bed forms in low-pressure regions (upwelling zones). Model-predicted contaminant concentrations are higher in downwelling zones than upwelling zones, reflecting the strong coupling that exists between transport and reaction in these systems. When flow-averaged, the concentration difference across upwelling and downwelling zones drives a net contaminant flux into the sediment bed proportional to the average downwelling velocity. The downwelling velocity is functionally equivalent to a mass transfer coefficient, and can be estimated from stream state variables including stream velocity, bed form geometry, and the hydraulic conductivity and porosity of the sediment. Increasing the mass transfer coefficient increases the fraction of streamwater cycling through the hyporheic zone (per unit length of stream) but also decreases the time contaminants undergo first-order reaction in the sediment. As a consequence, small changes in stream state variables can significantly alter the performance of hyporheic zone treatment systems.

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Modeling Benthic Oxygen Uptake by Pumping

Cited by 63 publications

References 11 publications

Quantifying biologically and physically induced flow and tracer dynamics in permeable sediments

Quantifying biologically and physically induced flow and tracer dynamics in permeable sediments

Hyporheic exchange of solutes and colloids with moving bed forms

First-Order Contaminant Removal in the Hyporheic Zone of Streams: Physical Insights from a Simple Analytical Model

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