A 3-D numerical model of the influence of meanders on groundwater discharge to a gaining stream in an unconfined sandy aquifer

Balbarini, Nicola; Boon, Wietse M.; Nicolajsen, Ellen; Nordbotten, Jan Martin; Bjerg, Poul Løgstrup; Binning, Philip John

doi:10.1016/j.jhydrol.2017.06.042

Cited by 22 publications

(24 citation statements)

References 56 publications

(37 reference statements)

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“…These trends in the hydraulic head are consistent over time and the temporal changes in groundwater head monitored in screens located in the shallow unconfined aquifer at wells 1448 and 1495 are similar to changes in stream water level (Balbarini et al ). Thus, groundwater flow conditions can be described by assuming a steady‐state simulation.…”

Section: Resultssupporting

confidence: 64%

“…The groundwater equipotential lines (m asl) and labels are marked with darker blue lines and numbers, respectively. The hydropotential map was developed by Balbarini et al () based on hydraulic head measurements from March 25 to 27, 2012. Wells used to develop the groundwater flow model and to collect contaminant concentration samples are indicated by black dots.…”

Section: Study Sitementioning

confidence: 99%

“…Grindsted Stream is a gaining stream with a catchment area of around 200 km 2 . The annual average flow is 2000 L/s and the stream is 8‐ to 12‐m wide and 1‐ to 2.5‐m deep (Balbarini et al ). Groundwater and hyporheic zone water samples collected below the streambed showed that groundwater contaminated by pharmaceutical compounds discharges along a 2‐km stretch of the stream (Rasmussen et al ; Sonne et al ).…”

Section: Study Sitementioning

confidence: 99%

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Assessing the Transport of Pharmaceutical Compounds in a Layered Aquifer Discharging to a Stream

Balbarini¹,

Frederiksen

Rønde

et al. 2019

Groundwater

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A groundwater plume containing high concentrations of pharmaceutical compounds, mainly sulfonamides, barbiturates, and ethyl urethane, in addition to chlorinated ethenes and benzene was investigated. The contamination originating from a former pharmaceutical industry discharges into a multilayered aquifer system and a downgradient stream. In this study, geological and hydrogeological data were integrated into a numerical flow model to examine identified trends using statistical approaches, including principal component analysis and hierarchal cluster analysis. A joint interpretation of the groundwater flow paths and contaminant concentrations in the different compartments (i.e., groundwater and hyporheic zone) provided insight on the transport processes of the different contaminant plumes to the stream. The analysis of historical groundwater concentrations of pharmaceutical compounds at the site suggested these compounds are slowly degrading. The pharmaceutical compounds migrate in both a deep semiconfined aquifer, as well as in the shallow unconfined aquifer, and enter the stream along a 2‐km stretch. This contrasted with the chlorinated ethenes, which mainly discharge to the stream as a focused plume from the unconfined aquifer. The integrated approach developed here, combining groundwater flow modeling and statistical analyses of the contaminant concentration data collected in groundwater and the hyporheic zone, lead to an improved understanding of the observed distribution of contaminants in the unconfined and semiconfined aquifers, and thus to their discharge to the stream. This approach is particularly relevant for large and long‐lasting contaminant sources and plumes, such as abandoned landfills and industrial production sites, where field investigations may be very expensive.

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Section: Resultssupporting

confidence: 64%

Section: Study Sitementioning

confidence: 99%

Section: Study Sitementioning

confidence: 99%

See 1 more Smart Citation

Assessing the Transport of Pharmaceutical Compounds in a Layered Aquifer Discharging to a Stream

Balbarini¹,

Frederiksen

Rønde

et al. 2019

Groundwater

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“…Most of the highest contaminant concentrations are located in the upper meltwater sand. The focus of this study is on the upper aquifer, which is in close hydraulic contact with the stream (Balbarini et al, ). The control plane (S–S′) employed to estimate the contaminant mass discharge at the Grindsted stream is located perpendicular to the groundwater flow and parallel to the stream meander (Figure c).…”

Section: Field Sitesmentioning

confidence: 99%

Geophysics‐Based Contaminant Mass Discharge Quantification Downgradient of a Landfill and a Former Pharmaceutical Factory

Balbarini

Rønde

Maurya

et al. 2018

Water Resources Research

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Contaminant mass discharge is a commonly applied tool to evaluate the environmental impact of contaminated sites on water resources. At large contaminated sites with heterogeneous sources, such as landfills, the number of wells available is often not sufficient, leading to a high uncertainty of mass discharge estimates. In this study, we tackle the uncertainty of the contaminant mass discharge due to low sampling densities by interpolating limited water‐sample data with the support of surface direct current resistivity and induced polarization geophysical data. The method relies on finding a conceptual link between the bulk conductivity imaged from geophysics and the contaminant concentrations. We investigate the link between (1) imaged bulk and electrical water conductivity, (2) water conductivity and conservative ionic species, (3) water conductivity and redox‐sensitive species, (4) water conductivity and semipersistent organic species, and (5) water conductivity and biodegradable organic compounds. The method successfully identify similarities between the distribution of the bulk conductivity and chloride and pharmaceutical compounds in a landfill leachate plume and between the bulk conductivity data and benzene and chlorinated ethenes for a contaminant plume from a former pharmaceutical factory. Contaminant concentrations were interpolated through regression kriging, using geophysical data as the dependent variable. The distribution of concentration determined with the novel method showed a lower mean relative estimation error than the traditional method of kriging only contaminant concentration data. At large sites, the method can improve contaminant mass discharge estimates, especially if surface geophysical measurements are integrated in the site investigation at an early stage.

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“…A sketch of the contaminant plume of total chlorinated ethenes is illustrated (using measurements from groundwater samplings from the water table to 3 m below). The approximate flow direction of the plume (shown as blue arrows) is derived from isopotential curves and groundwater flow modeling carried out at the site (Balbarini et al ; Rønde et al ). The dashed lines at the bottom map indicate the location of the cross sections described in the Methods section and Figure .…”

Section: Study Sitementioning

confidence: 99%

Phytoscreening for Vinyl Chloride in Groundwater Discharging to a Stream

Ottosen¹,

Rønde²,

Trapp³

et al. 2018

Groundwater Monitoring Rem

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This study applies an optimized phytoscreening method to locate a chlorinated ethene plume discharging into a stream. To evaluate the conditions most suitable for successful phytoscreening, trees along the stream bank were monitored through different seasons with different environmental conditions and hence different uptake/loss scenarios. Vinyl chloride (VC) as well as cis-dichloroethylene (cis-DCE), trichloroethylene (TCE), and tetrachloroethylene (PCE) were detected in the trees, documenting that phytoscreening is a viable method to locate chlorinated ethene plumes, including VC, discharging to streams. The results reveal, that phytoscreening for VC is more sensitive to environmental conditions affecting transpiration than for the other chlorinated ethenes detected. Conditions leading to higher groundwater uptake by transpiration than contaminant loss by diffusion from the tree trunks are optimal (e.g., low relative humidity, plentiful hours of sunshine and an intermediate air temperature). Additionally, low precipitation prior to the sampling event is beneficial, as uptake of infiltrating precipitation dilutes the concentration in the trees. All chlorinated ethenes were sensitive to dilution by clean precipitation and in some months, this resulted in no detection of contaminants in the trees at all. Under optimal environmental conditions the tree cores allowed detection of chlorinated solvents and their metabolites in the underlying groundwater. Whereas, for less ideal conditions there was a risk of no detection of the more volatile VC. This study is promising for the future applicability of phytoscreening to locate shallow groundwater contamination with the degradation products of chlorinated solvents.

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A 3-D numerical model of the influence of meanders on groundwater discharge to a gaining stream in an unconfined sandy aquifer

Cited by 22 publications

References 56 publications

Assessing the Transport of Pharmaceutical Compounds in a Layered Aquifer Discharging to a Stream

Assessing the Transport of Pharmaceutical Compounds in a Layered Aquifer Discharging to a Stream

Geophysics‐Based Contaminant Mass Discharge Quantification Downgradient of a Landfill and a Former Pharmaceutical Factory

Phytoscreening for Vinyl Chloride in Groundwater Discharging to a Stream

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