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Journal of Environmental Hydrology
ISSN 1058-3912 |
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Electronic Journal of the International Association for
Environmental Hydrology
JEH Volume 15 (2007), Paper 12 Posted May 21, 2007 NUMERICAL MODELING FOR RISK ASSESSMENT OF GROUNDWATER CONTAMINATION UNDER RIVER AND PUMPING EFFECTS
Budi Kurniawan ABSTRACT The two-dimensional groundwater flow and contaminant transport model is designed to support the analysis of a pathway of chlorinated hydrocarbons in a subsurface contaminated site. The proposed modeling approach employs hypothetical scenarios and demonstrates a capability to narrow down uncertain occurrences at the site. Modeling results show a comparison between chlorobenzene distribution in the absence and the presence of a river. Two observation wells indicate that on average 50 and 70 % of the concentration seeps out to the river from the aquifer, leading to contaminant spreading downstream. In addition, the flow and transport of contaminants at the site have been affected by pumping. Modeling estimated that more than 90 % of the contaminant concentration observed in three wells was reduced after 3 years of operation at four pumping wells during 2001 to 2003. This suggests that a high efficiency of multiple pumping techniques can prevent more migration of contaminants. On the other hand, it was shown that the part of the plume that extends more than 130 m downstream of the source cannot be captured by the current pumping since the predicted transport path is beyond well capture zones. It is concluded that a numerical approach using hypothetical scenarios can serve as a useful preliminary attempt to reconstruct the history of contaminant release. It can estimate the future pollutant distribution, in particular when observation data is insufficient. Reference: Kurniawan, B., and K. Jinno. 2007. Numerical modeling for risk assessment of groundwater contamination under river and pumping effects. Journal of Environmental Hydrology, Vol. 15, Paper 12. CONTACT: Budi Kurniawan Institute of Environmental Systems, Kyushu University 6-10-1, Hakozaki, Higashi-ku, Fukuoka-shi, Japan, 812 8581 E-mail: budikurniawan@menlh.go.id |
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