Design Screening Tools for Passive Funnel and Gate Systems

Sedivy, Robert A.; Shafer, John M.; Bilbrey, Lacrecia C.

doi:10.1111/j.1745-6592.1999.tb00195.x

Cited by 18 publications

(5 citation statements)

References 6 publications

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“…The adaptation of the FGS design is limited to straight FGSs [cf. Sedivy et al , 1999], meaning that all funnel segments are positioned on a straight line. All FGSs are modeled as fully penetrating the aquifer and as being keyed to an underlying aquitard.…”

Section: Methodsmentioning

confidence: 99%

Algorithmic funnel‐and‐gate system design optimization

Bürger

Bayer

Finkel

2007

Water Resources Research

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[1] Funnel-and-gate systems (FGSs), which constitute a common variant of permeable reactive barriers used for in situ treatment of groundwater, pose particular challenges to the task of design optimization. Because of the complex interplay of funnels and gates, the evolutionary algorithms applied have to cope with multimodality, nonseparability, and nonlinearity of the optimization task. We analyze these features in a test case, introducing an objective function for design cost and constraints to account for plume capture and detention time in the gate reactors. We show that the derandomized evolution strategy with covariance matrix adaptation (CMA-ES) does solve the given design optimization problem with high success rates. We further examine the performance of the algorithm for the example of four-gate systems in three heterogeneous template aquifers. Here a special focus is set on the parameterization of the FGS (i.e., the problem encoding). The comparison of three different encodings reveals their significance concerning the search progress and its success. Among the found optimal and near-optimal design solutions, mutual patterns were recognized. In particular, a large central barrier seems to be a superior feature.Citation: Bürger, C. M., P. Bayer, and M. Finkel (2007), Algorithmic funnel-and-gate system design optimization, Water Resour.

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Section: Methodsmentioning

confidence: 99%

Algorithmic funnel‐and‐gate system design optimization

Bürger

Bayer

Finkel

2007

Water Resources Research

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“…Previous investigators studied flow fields upgradient of interceptor trenches (gates) coupled with low-permeability walls (funnels), using groundwater flow models to identify travel pathways to these coupled configurations (Starr and Cherry, 1994;Sedivy et al, 1999;Bilbrey and Shafer, 2001). These studies considered advection, but not dispersion of contaminants in groundwater.…”

Section: Introductionmentioning

confidence: 98%

Effect of Setback Distance on Ability of Gravel Trenches to Intercept Contaminated Groundwater

Hudak

2005

Environ Monit Assess

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Computer simulations tested the ability of gravel interceptor trenches to capture a plume of contaminated groundwater. The plume had a maximum length and width of 87 and 19 m, respectively. In alternate simulations, one-meter wide trenches were located 5, 10, 20, and 50 m downgradient of the plume. A minimum trench length and time required to capture the plume was determined for each location (setback). The plume was considered captured if it passed entirely through a trench. A 21 m-long trench captured the plume at setbacks of 5 and 10 m. Minimum trench length increased to 23 and 25 m at setbacks of 20 and 50 m, respectively. Increased contaminant spreading with distance traveled dictated longer trenches at larger setbacks. Results of this study suggest that, at settings where contaminant plumes are carefully monitored and spatially defined, passive interceptor trenches should be close to a plume's leading tip and slightly longer than the maximum width of the plume.

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“…Several previous investigators applied particle-tracking (flow path) models to evaluate the performance of continuous trenches (Elder et al, 2002;Eykholt et al, 1999;Gupta & Fox, 1999;Hemsi & Shackelford, 2006;Hudak, 2004a) or funnel-and-gate structures (Bilbrey & Shafer, 2001;Cirpka et al, 2004;Hudak, 2004b;Sedivy et al, 1999) in various simulated subsurface environments. Using particle tracks to evaluate such structures may be problematic, because that approach typically ignores effects of hydrodynamic dispersion.…”

Section: Introductionmentioning

confidence: 99%

Performance assessment of hanging funnel‐and‐gate structures designed by reverse particle tracking for capturing polluted groundwater

Hudak

2007

Remediation Journal

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The objective of this study was to evaluate the capability of partially penetrating (hanging) funneland-gate structures, designed using reverse flow trajectories, for capturing plumes of contaminated groundwater. Linear capture structures, comprised of two slurry cutoff walls on either side of a permeable gate, were positioned perpendicular to regional groundwater flow in a hypothetical unconfined aquifer. A four-step approach was used for each of two simulated settings: (1) a numerical mass transport model generated a contaminant plume originating from a source area; (2) a particle-tracking model projected groundwater flow paths upstream from a treatment gate; (3) the structure was widened and deepened until bounding path lines contained the plume; and (4) mass transport simulation tested the ability of the structure to capture the plume. Results of this study suggest that designing funnel-and-gate structures using reverse particle tracking may result in too small a structure to capture a contaminant plume. This practice generally ignores effects of hydrodynamic dispersion, which may enlarge plumes such that contaminants move beneath or around a capture structure. This bypassing effect may be considerable even for low values of dispersivity. Particle-tracking approaches may also underestimate the amount of time required to reduce contaminant concentrations to acceptable levels. O

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Design Screening Tools for Passive Funnel and Gate Systems

Cited by 18 publications

References 6 publications

Algorithmic funnel‐and‐gate system design optimization

Algorithmic funnel‐and‐gate system design optimization

Effect of Setback Distance on Ability of Gravel Trenches to Intercept Contaminated Groundwater

Performance assessment of hanging funnel‐and‐gate structures designed by reverse particle tracking for capturing polluted groundwater

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