|Numerical modelling and hydrochemical characterisation of a fresh-water lens in the Belgian coastal plain|
Vandenbohede, A.; Lebbe, L. (2002). Numerical modelling and hydrochemical characterisation of a fresh-water lens in the Belgian coastal plain. Hydrogeol. J. 10(5): 576-586
In: Hydrogeology Journal. Springer: Heidelberg; Berlin. ISSN 1431-2174, more
Analytical techniques; Ground water; Hydrology; Ion exchange; Mathematical analysis; Salinity; Soils; Watersheds; Belgium, Belgian Coast [Marine Regions]; Marine; Brackish water; Fresh water
The distribution of fresh and salt water in coastal aquifers is influenced by many processes. The influence of aquifer heterogeneity and human interference such as land reclamation is illustrated in the Belgian coastal plain where, around A.D. 1200, the reclamation of a tidally influenced environment was completed. The aquifer, which was filled with salt water, was thereafter freshened. The areal distribution of peat, clay, silt and sand influences the general flow and distribution of fresh and salt water along with the drainage pattern and results in the development of fresh-water lenses. The water quality in and around the fresh-water lenses below an inverted tidal channel ridge is surveyed. The hydrochemical evolution of the fresh water lens is reconstructed, pointing to cation exchange, solution of calcite and the oxidation of organic material as the major chemical reactions. The formation and evolution of the fresh water lens is modelled using a two-dimensional density-dependent solute transport model and the sensitivity of drainage and conductivities are studied. Drainage level mainly influences the depth of the fresh-water lens, whereas the time of formation is mainly influenced by conductivity.