A natural gradient experiment on solute transport in a sand aquifer: Spatial variability of hydraulic conductivity and its role in the dispersion process

Water Resources Research - Tập 22 Số 13 - Trang 2069-2082 - 1986
E. A. Sudicky

Tóm tắt

The spatial variability of hydraulic conductivity at the site of a long‐term tracer test performed in the Borden aquifer was examined in great detail by conducting permeability measurements on a series of cores taken along two cross sections, one along and the other transverse to the mean flow direction. Along the two cross sections, a regular‐spaced grid of hydraulic conductivity data with 0.05 m vertical and 1.0 m horizontal spatial discretization revealed that the aquifer is comprised of numerous thin, discontinuous lenses of contrasting hydraulic conductivity. Estimation of the three‐dimensional covariance structure of the aquifer from the log‐transformed data indicates that an exponential covariance model with a variance equal to 0.29, an isotropic horizontal correlation length equal to about 2.8 m, and a vertical correlation length equal to 0.12 m is representative. A value for the longitudinal macrodispersivity calculated from these statistical parameters using three‐dimensional stochastic transport theory developed by L. W. Gelhar and C. L. Axness (1983) is about 0.6 m. For the vertically averaged case, the two‐dimensional theory developed by G. Dagan (1982, 1984) yields a longitudinal djspersivity equal to 0.45 m. Use of the estimated statistical parameters describing the ln (K) variability in Dagan's transient equations closely predicted the observed longitudinal and horizontal transverse spread of the tracer with time. Weak vertical and horizontal dispersion that is controlled essentially by local‐scale dispersion was obtained from the analysis. Because the dispersion predicted independently from the statistical description of the Borden aquifer is consistent with the spread of the injected tracer, it is felt that the theory holds promise for providing meaningful estimates of effective transport parameters in other complex‐structured aquifers.

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Tài liệu tham khảo

Ackerer P. W.Kinzelbach Modélisation du transport de contaminant par la méthode de marche au hazard: influence des variations du champ d'écoulement au cours du temp sur la dispersionProceedings International Association of Hydraulic Research Symposium on the Stochastic Approach to Subsurface FlowInt. Assoc. of Hydraul. Res.Montvillargenne FranceJune 1985.

10.1080/10643387909381669

Bear J., 1972, Dynamics of Fluids in Porous Media

10.1029/WR018i004p00835

10.1017/S0022112084002858

10.1029/WR022i09Sp0120S

10.1029/WR015i002p00269

Dieulin A. Propagation de pollution dans un aquifère alluvial l'effet de parcours Thése de Docteur‐Ingénieur l'Université Pierre et Marie Curie‐Paris VI 1980.

10.1029/WR011i005p00725

Freyberg D. L., A natural gradient experiment on solute transport in a sand aquifer, 2, Spatial moments and the advection and dispersion of nonreactive tracers, Water Resour. Res., 10.1029/WR022i013p02031

10.1029/WR022i09Sp0135S

10.1029/WR019i001p00161

10.1029/WR015i006p01387

10.1029/WR020i010p01337

10.1029/WR021i004p00563

Jenkins G. M., 1968, Spectral Analysis and its Applications

10.1016/0022-1694(83)90221-4

Mackay D. M., A natural gradient experiment on solute transport in a sand aquifer, 1, Approach and overview of plume movement, Water Resour. Res., 10.1029/WR022i013p02017

10.1029/WR016i005p00901

Nwankwor G. Delayed yield processes and specific yield in a shallow sand aquifer Ph.D. thesis Univ. of Waterloo Waterloo Ont. 1985.

10.1007/BF01032006

Sudicky E. A. An advection‐diffusion theory of contaminant transport for stratified porous media Ph.D. thesis Univ. of Waterloo Waterloo Ont. 1983.

10.1016/0022-1694(83)90224-X

10.1137/0144027

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Water Resources Research

Tập 22 Số 13

2069-2082

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