Calibration of spatial aquitard distribution using hydraulic head changes and regularisation

Wiese, Bernd; Nützmann, Gunnar

doi:10.1016/j.jhydrol.2011.07.015

Cited by 11 publications

(4 citation statements)

References 19 publications

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“…Leakage can exist across an aquitard, which can strongly affect the drawdown response of an underlying confined aquifer during groundwater pumping ( Jacob, 1946). Aquitard hydrogeology has been well documented, with the majority of the research concentrated on clay-rich aquitards (Desaulniers et al, 1981;Hendry et al, 2004;Hiscock and Tabatabai Najafi, 2011;Larroque et al, 2013;Machado et al, 2007;Wiese and Nützmann, 2011). Having a greater permeability than clay-rich aquitards, silty aquitards have a greater average linear velocity and therefore greater potential for contaminants to reach the aquifer faster.…”

Section: Chloride Dispersion Across Silt Deposits In a Glaciated Bedrmentioning

confidence: 99%

Chloride Dispersion across Silt Deposits in a Glaciated Bedrock River Valley

2014

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Soil and groundwater from the Neponset River floodplain deposit that receive high concentrations of deicing agents from nearby highways were investigated. The silty sand floodplain is separated by a silty aquitard from the underlying aquifer that serves as a public water supply. We made a transport-based assessment of the capacity of the aquitard to protect the underlying aquifer. One hundred seventeen soil samples and 469 groundwater samples collected during a period of 4 yr from boreholes and 10 wells grouped in two well clusters were analyzed for dissolved Cl concentration. The soil characterization and groundwater monitoring results agreed, showing a very slow change in subsurface Cl contamination with time. These data also calibrated a vertical one-dimensional advective-dispersive transport model across the deposits. Advective transport dominated only in the top 3.37 m of the floodplain deposit, with dispersion being the main transport mechanism below this depth. Due to the silty nature of the aquitard, dispersion rather than diffusion was the main transport mechanism into the floodplain-aquitard system. Soil and groundwater quality data confirmed a Cl concentration at the floodplain surface near the highway runoff drainage outlets of 2450 mg L. The model estimated a vertical dispersivity at the site of 8 mm and a vertical hydrodynamic dispersion coefficient of 3.71 × 10 m s. These data confirmed the aquitard's capacity to contain deicing agents, protecting the underlying aquifer from contamination.

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Section: Chloride Dispersion Across Silt Deposits In a Glaciated Bedrmentioning

confidence: 99%

Chloride Dispersion across Silt Deposits in a Glaciated Bedrock River Valley

2014

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“…Most mixed samples are identified at Tegel BF, due to vertical stratification of different ages of bank filtrate (Wiese & Nützmann 2011).…”

Section: Mixingmentioning

confidence: 99%

“…For the Tegel BF site results were reported on transient hydraulics and transport (Wiese & Nützmann, 2011;Wiese, 2006), environmental tracers (Massmann et al, 2008c) and organic compounds (Grünheid et al, 2005). Details of the Wannsee BF site were presented focussing on redox conditions (Massmann et al, 2008a), re-aeration due to waterlevel fluctuations (Massmann & Sültenfuß, 2008, Kofahl et al, 2009, phenazone type PhACs (Massmann et al, 2008a) and antimicrobial residues (Heberer et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Removal kinetics of organic compounds and sum parameters under field conditions for managed aquifer recharge

et al. 2011

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Highlights:removal of trace organics and sum parameters during bank filtration late data aggregation removal kinetics: redox conditions, temporal removal, threshold concentration, residual concentration, site specifics, large database Abstract Managed aquifer recharge (MAR) provides efficient removal for many organic compounds and sum parameters. However, observed in situ removal efficiencies tend to scatter and can not be predicted easily. In this paper, a method is introduced which allows to identify and eliminate biased samples and to quantify simultaneously the impact of (i) redox conditions (ii) kinetics (iii) residual threshold values below which no removal occurs and (iv) field site specifics. It enables to rule out spurious correlations between these factors and therefore improves the predictive power. The method is applied to an extensive database from three MAR field sites which was compiled in the NASRI project -2005. Removal characteristics for 38 organic parameters are obtained, of which 9 are analysed independently in 2 different laboratories. Out of these parameters, mainly pharmaceutically active compounds (PhAC) but also sum parameters and industrial chemicals, four compounds are shown to be readily removable whereas six are persistent. All partly removable compounds show a redox dependency and most of them reveal either kinetic dependencies or residual threshold values, which are determined. Differing removal efficiencies at different field sites can usually be explained by characteristics (i) to (iii).

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“…Natural stimuli combined with the data fusion concept can facilitate the basin‐scale tomographic surveys (Yeh et al ). Numerical analysis with optimal estimation software (e.g., PEST) can be used to calibrate the aquifer and aquitard properties (Schroth and Narasimhan ; Machado et al ; Wiese and Nützmann ). This method can obtain the large‐scale hydraulic properties of the aquifer system, with the numerical results matching the observation data.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Hydraulic Properties of Aquitards Using Earthquake‐Triggered Groundwater Variation

et al. 2017

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The hydraulic properties of aquitards are not easily obtained because monitoring wells are usually installed in aquifers for groundwater resources management. Earthquake-induced crust stress (strain) triggers groundwater level variations over a short period of time in a large area. These groundwater anomalies can be used to investigate aquifer systems. This study uses a poroelastic model to fit the postseismic variations of groundwater level triggered by the Chi-Chi earthquake to evaluate the hydraulic properties of aquitards in the Jhoushuei River alluvial fan (JRAF), Taiwan. Six of the adopted eight wells with depths of 70 to 130 m showed good agreement with the recovery theory. The mean hydraulic conductivities (K) of the aquifers for the eight wells are 1.62 × 10 to 9.06 × 10 m/s, and the thicknesses are 18.8 to 46.1 m. The thicknesses of the aquitards are 11.3 to 42.0 m. Under the isotropic assumption for K, the estimated values of K for the aquitards are 3.0 × 10 to 2.1 × 10 m/s, corresponding to a silty medium. The results match the values obtained for the geological material of the drilling core and those reported in previous studies. The estimated values were combined with those given in previous studies to determine the distribution of K in the first two aquitards in the JRAF. The distribution patterns of the aquitards reflect the sedimentary environments and fit the geological material. The proposed technique can be used to evaluate the K value of aquitards using inverse methods. The inversion results can be used in hydrogeological analyses, contaminant modeling, and subsidence evaluation.

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Calibration of spatial aquitard distribution using hydraulic head changes and regularisation

Cited by 11 publications

References 19 publications

Chloride Dispersion across Silt Deposits in a Glaciated Bedrock River Valley

Chloride Dispersion across Silt Deposits in a Glaciated Bedrock River Valley

Removal kinetics of organic compounds and sum parameters under field conditions for managed aquifer recharge

Evaluation of Hydraulic Properties of Aquitards Using Earthquake‐Triggered Groundwater Variation

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