Calibration and Reliability in Groundwater
Modelling: Credibility of Modelling
(Proceedings of ModelCARE 2007 Conference, held in
Denmark, September 2007). IAHS Publ. 320, 2008, 191-196.
Geochemical
processes and their modelling at the fresh and salt water mixing zone
K. JINNO, T. HOSOKAWA, K. AKAGI, Y. HIROSHIRO
& J. YASUMOTO
Institute of Environmental Systems, Graduate
School of Engineering, Kyushu University,
744 Motooka Nishi-ku Fukuoka, 819-0395 Japan
Abstract Oxidation–reduction
geochemical processes coupled with mass transport in a coastal aquifer is a
unique subsurface environmental phenomenon to model. When a porous material is
contaminated by organic carbons, nitrate is denitrified and manganese dioxide
and oxi-iron hydroxide would be reduced. However, it is expected that the reduced
divalent iron is oxidized once again by seawater when discharged to the sea. The
paper discusses a numerical model of transport and geochemical reaction
processes along the mixing zone of fresh and reduced salt water in a coastal
aquifer. By comparing the numerical solution with experimental observations for
the precipitation of divalent iron along the mixing zone, the validity of the model
is demonstrated.
Key words coastal aquifer; saltwater intrusion; iron and oxygen transport; oxi-iron hydroxide