Modelling Water Flow and Solute Transport in Heterogeneous Unsaturated Porous Media

  • Gerardo Severino
  • Alessandro Santini
  • Valeria Marina Monetti
Part of the Springer Optimization and Its Applications book series (SOIA, volume 25)


New results concerning flow velocity and solute spreading in an unbounded three-dimensional partially saturated heterogeneous porous formation are derived. Assuming that the effective water content is a uniformly distributed constant, and dealing with the recent results of Severino and Santini (Advances in Water Resources 2005;28:964–974) on mean vertical steady flows, first-order approximation of the velocity covariance , and concurrently of the resultant macrodispersion coefficients are calculated. Generally, the velocity covariance is expressed via two quadratures. These quadratures are further reduced after adopting specific (i.e., exponential) shape for the required (cross)correlation functions. Two particular formation structures that are relevant for the applications and lead to significant simplifications of the computational aspect are also considered.

It is shown that the rate at which the Fickian regime is approached is an intrinsic medium property, whereas the value of the macrodispersion coefficients is also influenced by the mean flow conditions as well as the (cross)variances σ2 γ of the input parameters. For a medium of given anisotropy structure, the velocity variances reduce as the medium becomes drier (in mean), and it increases with σ2 γ. In order to emphasize the intrinsic nature of the velocity autocorrelation, good agreement is shown between our analytical results and the velocity autocorrelation as determined by Russo (Water Resources Research 1995;31:129–137) when accounting for groundwater flow normal to the formation bedding. In a similar manner, the intrinsic character of attainment of the Fickian regime is demonstrated by comparing the scaled longitudinal macrodispersion coefficients \(\frac{D_{11} (t)}{{D_{11}}^{(\infty)}}\) as well as the lateral displacement variance \(\frac{X_{22}(t)}{{X_{22}}^{(\infty)}} = \frac{X_{33} (t)}{{X_{33}}^{(\infty)}}\) with the same quantities derived by Russo (Water Resources Research 1995;31:129–137) in the case of groundwater flow normal to the formation bedding.


Groundwater Flow Pressure Head Gaussian Model Vadose Zone Formation Property 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The authors express sincere thanks to Dr. Gabriella Romagnoli for reviewing the manuscript. This study was supported by the grant PRIN (# 2004074597).


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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Gerardo Severino
    • 1
  • Alessandro Santini
  • Valeria Marina Monetti
  1. 1.Division of Water Resources ManagementUniversity of Naples Federico IIItaly

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