Comparison of Slug Test Methodologies for Determination of Hydraulic Conductivity in Fine-Grained Sediments

2009 ◽  
pp. 152-152-13 ◽  
Author(s):  
BL Herzog ◽  
WJ Morse
1992 ◽  
Vol 136 (1-4) ◽  
pp. 87-106 ◽  
Author(s):  
Klaus Hinsby ◽  
Poul L. Bjerg ◽  
Lars J. Andersen ◽  
Bent Skov ◽  
Erik V. Clausen

2003 ◽  
Vol 36 ◽  
pp. 103-109 ◽  
Author(s):  
Bernd Kulessa ◽  
Tavi Murray

AbstractWe investigate the differences in subglacial hydraulic properties between Bakaninbreen, a surge-type glacier in southern Svalbard, and midre Lovénbreen, a non-surge-type glacier in northwest Svalbard, using slug tests. At Bakaninbreen, underlain by fine-grained glacial till and marine sediments, slug-test responses were underdamped and are analyzed with the Van der Kamp method using a fully penetrating screen. At midre Lovénbreen, underlain by metres-thick permafrost consisting of coarse clasts, ice and water, slug-test responses were overdamped and are analyzed with the Butler–Garnett method using a partially penetrating screen. We calculate typical hydraulic conductivities of 8.2 ± 7.8 x 10–3 ms–1 for Bakaninbreen, and 1.9 ± 0.5 × 10–5 m s–1 for midre Lovénbreen, after correction for a high-conductivity skin. At Bakaninbreen, late surge-induced subglacial sediment dilation probably caused marked hydraulic conductivity enhancement, which could be widespread during times of peak ice flow. We argue that the flow pathways in the permafrost beneath midre Lovénbreen are present, though limited in terms of their discharge capacity, which in combination with drilling-based observations and independent evidence suggests that midre Lovénbreen is not capable of surging.


1999 ◽  
Vol 30 (4-5) ◽  
pp. 333-360 ◽  
Author(s):  
Larry McKay ◽  
Johnny Fredericia ◽  
Melissa Lenczewski ◽  
Jørn Morthorst ◽  
Knud Erik S. Klint

A field experiment shows that rapid downward migration of solutes and microorganisms can occur in a fractured till. A solute tracer, chloride, and a bacteriophage tracer, PRD-1, were added to groundwater and allowed to infiltrate downwards over a 4 × 4 m area. Chloride was detected in horizontal filters at 2.0 m depth within 3-40 days of the start of the tracer test, and PRD-1 was detected in the same filters within 0.27 - 27 days. At 2.8 m depth chloride appeared in all the filters, but PRD-1 appeared in only about one-third of the filters. At 4.0 m depth chloride appeared in about one-third of the filters and trace amounts of PRD-1 were detected in only 2 of the 36 filters. Transport rates and peak tracer concentrations decreased with depth, but at each depth there was a high degree of variability. The transport data is generally consistent with expectations based on hydraulic conductivity measurements and on the observed density of fractures and biopores, both of which decrease with depth. Transport of chloride was apparently retarded by diffusion into the fine-grained matrix between fractures, but the rapid transport of PRD-1, with little dispersion, indicates that it was transported mainly through the fractures.


Author(s):  
Guglielmo Federico Antonio Brunetti ◽  
Samuele De Bartolo ◽  
Carmine Fallico ◽  
Ferdinando Frega ◽  
Maria Fernanda Rivera Velásquez ◽  
...  

AbstractThe spatial variability of the aquifers' hydraulic properties can be satisfactorily described by means of scaling laws. The latter enable one to relate the small (typically laboratory) scale to the larger (typically formation/regional) ones, therefore leading de facto to an upscaling procedure. In the present study, we are concerned with the spatial variability of the hydraulic conductivity K into a strongly heterogeneous porous formation. A strategy, allowing one to identify correctly the single/multiple scaling of K, is applied for the first time to a large caisson, where the medium was packed. In particular, we show how to identify the various scaling ranges with special emphasis on the determination of the related cut-off limits. Finally, we illustrate how the heterogeneity enhances with the increasing scale of observation, by identifying the proper law accounting for the transition from the laboratory to the field scale. Results of the present study are of paramount utility for the proper design of pumping tests in formations where the degree of spatial variability of the hydraulic conductivity does not allow regarding them as “weakly heterogeneous”, as well as for the study of dispersion mechanisms.


Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1131
Author(s):  
Soonkie Nam ◽  
Marte Gutierrez ◽  
Panayiotis Diplas ◽  
John Petrie

This paper critically compares the use of laboratory tests against in situ tests combined with numerical seepage modeling to determine the hydraulic conductivity of natural soil deposits. Laboratory determination of hydraulic conductivity used the constant head permeability and oedometer tests on undisturbed Shelby tube and block soil samples. The auger hole method and Guelph permeameter tests were performed in the field. Groundwater table elevations in natural soil deposits with different hydraulic conductivity values were predicted using finite element seepage modeling and compared with field measurements to assess the various test results. Hydraulic conductivity values obtained by the auger hole method provide predictions that best match the groundwater table’s observed location at the field site. This observation indicates that hydraulic conductivity determined by the in situ test represents the actual conditions in the field better than that determined in a laboratory setting. The differences between the laboratory and in situ hydraulic conductivity values can be attributed to factors such as sample disturbance, soil anisotropy, fissures and cracks, and soil structure in addition to the conceptual and procedural differences in testing methods and effects of sample size.


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