Validity of a sharp-interface approach in confined coastal aquifers
Sakr, S.A. (1999). Validity of a sharp-interface approach in confined coastal aquifers. Natuurwet. Tijdschr. 79(1-4): 85-90
In: Natuurwetenschappelijk Tijdschrift. L. Walschot/Natuur- en Geneeskundige Vennootschap: Gent. ISSN 0770-1748, more
Also appears in:De Breuck, W.; Walschot, L. (Ed.) (1999). Proceedings of the 15th Salt-Water Intrusion Meeting Ghent (Belgium), 25-29 May 1998. Natuurwetenschappelijk Tijdschrift, 79(1-4). Natuurwetenschappelijk Tijdschrift: Gent. 307 pp., more
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| Keywords |
Fronts > Oceanic fronts > Estuarine front
Models
Water > Ground water
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| Abstract |
The problem of sea-water intrusion is considered for the case of a confined coastal aquifer in which there is steady seaward flow of fresh water. Using the GWCH20 model the problem is solved first for the case of no dispersion where a distinct interface exists separating the fresh from the salt water. The problem is solved 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 that density-dependent solute transport.To investigate the limitation of the sharp interface approach in coastal aquifers for both steady and unsteady-state conditions, the problem is solved twice using the two models for different parameter values. These parameters are combined in dimensionless form resulting in three parameters named: seepage factor (A); dispersion to advection ratio (B); and geometry ratio (C). Using the density-dependent model, the dimensionless width of the transition zone (W/d) is determined for different values of A, B, and C. The analysis showed that at any time level the sharp interface applicability is only valid when the system is dominated by advection. In other words when B between 0 and 5% for all values of A and C or when A is larger than or equal to 65% for all values of B and C. |
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