The uncertainty of mass discharge measurements using pumping methods under simplified conditions

Chen, Xiaosong; Brooks, Michael C.; Wood, A. Lynn

doi:10.1016/j.jconhyd.2013.09.006

Cited by 5 publications

(7 citation statements)

References 49 publications

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“…For example, Troldborg et al (2012) reported a decrease in ṁ uncertainty as the control plane distance from the source increased due to greater lateral transport from transverse dispersion. Chen et al (2014) also noted a decrease in ṁ uncertainty as the plume width increased relative to the well spacing.…”

Section: Screening-level Uncertainty Equationsmentioning

confidence: 83%

“…This approach is similar to that used by Chen et al (2014), who assumed C varied only in the y-direction according to a normal distribution within a homogeneous K field. Expressing J directly as either a bivariate normal distribution in Eq.…”

Section: Screening-level Uncertainty Equationsmentioning

confidence: 99%

“…Specific methods used to measure J and ṁ have been summarized in several publications (e.g., Chen et al, 2014;ITRC, 2010;Kavanaugh et al, 2011;Kübert and Finkel, 2006), and can be divided into two broad categories: pointmeasurement methods and pumping-measurement methods. Point-measurement methods are based on sampling techniques with relatively small sampling volumes, and most often consist either of applications based on multi-level samplers (e.g., Freitas et al, 2011;Guilbeault et al, 2005;Kao and Wang, 2001) or passive flux meters (PFMs) (e.g., Annable et al, 2005;Hatfield et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…A number of studies have been completed on pointmeasurement method uncertainty (Béland-Pelletier et al, 2011;Cai et al, 2011Cai et al, , 2012Chen et al, 2014;Klammler et al, 2012;Kübert and Finkel, 2006;Li and Abriola, 2009;Li et al, 2007;MacKay et al, 2012;Schwede and Cirpka, 2010;Troldborg et al, 2010Troldborg et al, , 2012. Two of these studies were based on field trials (Béland-Pelletier et al, 2011;MacKay et al, 2012), two of the studies used flow and transport simulations within Monte Carlo frameworks (Chen et al, 2014;Kübert and Finkel, 2006); two more studies likewise used flow and transport simulations within Monte Carlo frameworks, but simulations were conditioned to field data (Schwede and Cirpka, 2010;Troldborg et al, 2010); and the remaining studies employed various conditional, geostatistical techniques, wherein one or more parameters across the control plane were treated as spatial random variables.…”

Section: Introductionmentioning

confidence: 99%

“…Two of these studies were based on field trials (Béland-Pelletier et al, 2011;MacKay et al, 2012), two of the studies used flow and transport simulations within Monte Carlo frameworks (Chen et al, 2014;Kübert and Finkel, 2006); two more studies likewise used flow and transport simulations within Monte Carlo frameworks, but simulations were conditioned to field data (Schwede and Cirpka, 2010;Troldborg et al, 2010); and the remaining studies employed various conditional, geostatistical techniques, wherein one or more parameters across the control plane were treated as spatial random variables. Kubert and Finkel (2006) conducted an extensive Monte Carlo analysis on a hypothetical site to evaluate uncertainty as a function of measurement method, sampling density (S D ), and hydraulic conductivity (K) heterogeneity.…”

Section: Introductionmentioning

confidence: 99%

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Screening-level estimates of mass discharge uncertainty from point measurement methods

Brooks

Young

Wood

et al. 2015

Journal of Contaminant Hydrology

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The uncertainty of mass discharge measurements associated with point-scale measurement techniques was investigated by deriving analytical solutions for the mass discharge coefficient of variation for two simplified, conceptual models. In the first case, a depth-averaged domain was assumed, consisting of one-dimensional groundwater flow perpendicular to a one-dimensional control plane of uniformly spaced sampling points. The contaminant flux along the control plane was assumed to be normally distributed. The second case consisted of one-dimensional groundwater flow perpendicular to a two-dimensional control plane of uniformly spaced sampling points. The contaminant flux in this case was assumed to be distributed according to a bivariate normal distribution. The center point for the flux distributions in both cases was allowed to vary in the domain of the control plane as a uniform random variable. Simplified equations for the uncertainty were investigated to facilitate screening-level evaluations of uncertainty as a function of sampling network design. Results were used to express uncertainty as a function of the length of the control plane and number of wells, or alternatively as a function of the sample spacing. Uncertainty was also expressed as a function of a new dimensionless parameter, Ω, defined as the ratio of the maximum local flux to the product of mass discharge and sample density. Expressing uncertainty as a function of Ω provided a convenient means to demonstrate the relationship between uncertainty, the magnitude of a local hot spot, magnitude of mass discharge, distribution of the contaminant across the control plane, and the sampling density.

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Section: Screening-level Uncertainty Equationsmentioning

confidence: 83%

Section: Screening-level Uncertainty Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Screening-level estimates of mass discharge uncertainty from point measurement methods

Brooks

Young

Wood

et al. 2015

Journal of Contaminant Hydrology

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3D numerical modelling of a pulsed pumping process of a large DNAPL pool: In situ pilot-scale case study of hexachlorobutadiene in a keyed enclosure

Giraud

Gonçalvès

Paris

et al. 2018

Journal of Contaminant Hydrology

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Source strength functions from long-term monitoring data and spatially distributed mass discharge measurements

Brooks

Wood

Cho

et al. 2018

Journal of Contaminant Hydrology

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Source strength functions (SSF), defined as contaminant mass discharge or flux-averaged concentration from dense nonaqueous phase liquid (DNAPL) source zones as a function of time, provide a quantitative model of DNAPL source-zone behavior. Such information is useful for calibration of screening-level models to assist with site management decisions. We investigate the use of historic data collected during long-term monitoring (LTM) activities at a site in Rhode Island to predict the SSF based on temporal mass discharge measurements at a fixed location, as well as SSF estimation using mass discharge measurements at a fixed time from three spatially distributed control planes. Mass discharge based on LTM data decreased from ~300 g/day in 1996 to ~70 g/day in 2012 at a control plane downgradient of the suspected DNAPL source zone, and indicates an overall decline of ~80% in 16 years. These measurements were compared to current mass discharge measurements across three spatially distributed control planes. Results indicate that mass discharge increased in the downgradient direction, and was ~6 g/day, ~37 g/day, and ~400 g/day at near, intermediate, and far distances from the suspected source zone, respectively. This behavior was expected given the decreasing trend observed in the LTM data at a fixed location. These two data sets were compared using travel time as a means to plot the data sets on a common axis. The similarity between the two data sets gives greater confidence to the use of this combined data set for site-specific SSF estimation relative to either the sole use of LTM or spatially distributed data sets.

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The uncertainty of mass discharge measurements using pumping methods under simplified conditions

Cited by 5 publications

References 49 publications

Screening-level estimates of mass discharge uncertainty from point measurement methods

Screening-level estimates of mass discharge uncertainty from point measurement methods

3D numerical modelling of a pulsed pumping process of a large DNAPL pool: In situ pilot-scale case study of hexachlorobutadiene in a keyed enclosure

Source strength functions from long-term monitoring data and spatially distributed mass discharge measurements

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