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Groundwater Flow Field Distortion by Monitoring Wells and Passive Flux Meters
Author(s) -
Verreydt G.,
Bronders J.,
Van Keer I.,
Diels L.,
Vanderauwera P.
Publication year - 2015
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/gwat.12290
Subject(s) - groundwater , distortion (music) , groundwater flow , aquifer , flow (mathematics) , flux (metallurgy) , hydraulic conductivity , field (mathematics) , filter (signal processing) , flow measurement , mechanics , geology , environmental science , geotechnical engineering , soil science , hydrology (agriculture) , engineering , materials science , physics , mathematics , electrical engineering , soil water , amplifier , cmos , pure mathematics , metallurgy
Abstract Due to differences in hydraulic conductivity and effects of well construction geometry, groundwater lateral flow through a monitoring well typically differs from groundwater flow in the surrounding aquifer. These differences must be well understood in order to apply passive measuring techniques, such as passive flux meters (PFMs) used for the measurement of groundwater and contaminant mass fluxes. To understand these differences, lab flow tank experiments were performed to evaluate the influences of the well screen, the surrounding filter pack and the presence of a PFM on the natural groundwater flux through a monitoring well. The results were compared with analytical calculations of flow field distortion based on the potential theory of Drost et al. (1968). Measured well flow field distortion factors were found to be lower than calculated flow field distortion factors, while measured PFM flow field distortion factors were comparable to the calculated ones. However, this latter is not the case for all conditions. The slotted geometry of the well screen seems to make a correct analytical calculation challenging for conditions where flow field deviation occurs, because the potential theory assumes a uniform flow field. Finally, plots of the functional relationships of the distortion of the flow field with the hydraulic conductivities of the filter screen, surrounding filter pack and corresponding radii make it possible to design well construction to optimally function during PFM applications.