Validity of a sharp-interface model in a confined coastal aquifer |
| |
| Authors: | Sameh A Sakr |
| |
| Institution: | (1) Research Institute for Ground Water, El-Kanater El-Khairiya, Cairo, Egypt Fax: +1-202-218-8729, EG |
| |
| Abstract: | The problem of seawater intrusion is considered for the case of a confined coastal aquifer in which there is steady seaward
flow of fresh water. Using the GWCH2O model, the problem is solved first for the case of no dispersion where a distinct interface
exists separating the fresh water from the salt water. The problem is solved next by taking into account dispersion and diffusion
of the salt-water component, along with the density effect. In this respect, a two-dimensional finite-element model, 2D-VDTRAN,
is developed to simulate density-dependent solute transport.
To investigate the limitation of the sharp-interface approach in coastal aquifers for conditions of both steady state and
unsteady state, the problem is solved twice using the two models with different parameter values. These parameters are combined
in dimensionless form, resulting in four named parameters: seepage factor (A); dispersion-to-advection ratio (B); geometry
ratio (C); and time-scale factor (T). Using the density-dependent model, the dimensionless width of the transition zone (W/L)
is determined for different values of A, B, C, and T. Steady-state simulations show that the sharp-interface approach is valid
only when the system is dominated by advection, i.e., when 0<B≤5% for all values of A and C, or when A≥65% for all values
of B and C. However, the unsteady-state analysis shows that the applicability of the sharp-interface approach is sufficiently
accurate at early times.
Received, October 1997 Revised, June 1998, October 1998 Accepted, November 1998 |
| |
| Keywords: | diffusion salt-water/fresh-water relations sharp interface numerical modeling |
| 本文献已被 SpringerLink 等数据库收录！ |
|
