Numerical investigation of seawater intrusion at Gooburrum, Bundaberg, Queensland, Australia


Autoria(s): Zhang, Q.; Volker, R. E.; Lockington, D. A.
Contribuinte(s)

C. Voss

Data(s)

01/01/2004

Resumo

Seawater intrusion in coastal agricultural areas due to groundwater abstraction is a major environmental problem along the northeastern coast of Australia. Management options are being explored using numerical modelling, however, questions remain concerning the appropriate level of sophistication in models, choice of seaward boundary conditions, and how to accommodate heterogeneity and data uncertainty. The choice of seaward boundary condition is important since it affects the amount of salt transported into the aquifers and forms the focus of the present study. The impact of this boundary condition is illustrated for the seawater-intrusion problem in the Gooburrum aquifers, which occur within Tertiary sedimentary strata. A two-dimensional variable-density groundwater and solute-transport model was constructed using the computer code 2DFEMFAT (Cheng et al. 1998). The code was tested against an experiment for a steady-state freshwater-saltwater interface and against the Elder (Elder 1967) free-convection problem. Numerical simulations show that the imposition of the commonly-used equivalent hydrostatic freshwater heads, combined with a constant salt concentration at the seaward boundary, results in overestimated seawater intrusion in the lower Gooburrum aquifer. Since the imposition of this boundary condition allows water flow across the boundary, which subsequently takes salt into the aquifer, a careful check is essential to estimate whether too much mass of salt is introduced.

Identificador

http://espace.library.uq.edu.au/view/UQ:74030

Idioma(s)

eng

Publicador

Springer-Verlag

Palavras-Chave #Geosciences, Multidisciplinary #Water Resources #Seawater Intrusion #Boundary Condition #Steady-state Solution #Numerical Modelling #Coastal Aquifers #Coupled Groundwater-flow #Variable-density Flow #Porous Medium #Transport #Dispersion #Convection #Aquifers #Model #C1 #291102 Bio-remediation #770502 Land and water management
Tipo

Journal Article