Soil Salinity Effects on the Spatial Variability of Hydraulic Conductivity

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.

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EFFECT OF SPATIAL VARIABILITY IN HYDRAULIC CONDUCTIVITY ON WATER TABLE DRAWDOWN

Transactions of the ASAE ◽

10.13031/2013.21430 ◽

1997 ◽

Vol 40 (2) ◽

pp. 371-375

Author(s):

S. O. Prasher ◽

M. Singh ◽

A. K. Maheshwari ◽

R. S. Clemente

Keyword(s):

Hydraulic Conductivity ◽

Spatial Variability ◽

Water Table

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Experimental investigation to characterize simple versus multi scaling analysis of hydraulic conductivity at a mesoscale

Stochastic Environmental Research and Risk Assessment ◽

10.1007/s00477-021-02079-w ◽

2021 ◽

Author(s):

Guglielmo Federico Antonio Brunetti ◽

Samuele De Bartolo ◽

Carmine Fallico ◽

Ferdinando Frega ◽

Maria Fernanda Rivera Velásquez ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Spatial Variability ◽

Hydraulic Properties ◽

Scaling Laws ◽

Scaling Analysis ◽

Field Scale ◽

Porous Formation ◽

Proper Design ◽

First Time

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.

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Development of a Practical Model for Predicting Soil Salinity in a Salt Marsh in the Arakawa River Estuary

Water ◽

10.3390/w13152054 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2054

Author(s):

Naoki Kuroda ◽

Katsuhide Yokoyama ◽

Tadaharu Ishikawa

Keyword(s):

Salt Marsh ◽

Hydraulic Conductivity ◽

Shallow Water ◽

Soil Salinity ◽

River Estuary ◽

Flow Simulation ◽

Design Tool ◽

Water Model ◽

Shallow Water Model ◽

Practical Model

Our group has studied the spatiotemporal variation of soil and water salinity in an artificial salt marsh along the Arakawa River estuary and developed a practical model for predicting soil salinity. The salinity of the salt marsh and the water level of a nearby channel were measured once a month for 13 consecutive months. The vertical profile of the soil salinity in the salt marsh was measured once monthly over the same period. A numerical flow simulation adopting the shallow water model faithfully reproduced the salinity variation in the salt marsh. Further, we developed a soil salinity model to estimate the soil salinity in a salt marsh in Arakawa River. The vertical distribution of the soil salinity in the salt marsh was uniform and changed at almost the same time. The hydraulic conductivity of the soil, moreover, was high. The uniform distribution of salinity and high hydraulic conductivity could be explained by the vertical and horizontal transport of salinity through channels burrowed in the soil by organisms. By combining the shallow water model and the soil salinity model, the soil salinity of the salt marsh was well reproduced. The above results suggest that a stable brackish ecotone can be created in an artificial salt marsh using our numerical model as a design tool.

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