Laboratory Experiments for Seawater Intrusion into Freshwater Aquifer with Heterogeneity

HR: 1340h
AN: H23G-1702 [Abstracts]
TI: Laboratory Experiments for Seawater Intrusion into Freshwater Aquifer with Heterogeneity
AU: * Maekawa, K
EM: maekawa.keisuke@jaea.go.jp
AF: Japan Atomic Energy Agency, Hokushin 432-2, Horonobe-cho, Hokkaido, Horonobe-cho, 098-3224, Japan
AU: Karasaki, K
EM: kkarasaki@lbl.gov
AF: Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., MS 90-1116, Berkeley, CA 94720, United States
AU: Takasu, T
EM: takasu.tamio@jaea.go.jp
AF: Inspection Development Company Ltd., 4-33, Muramatsu, Tokai-mura Naka-gun, Ibaraki, Tokai-mura, 319-1194, Japan
AB: It is important for safety assessment of high-level radioactive waste geologic disposal to understand groundwater flow in deep underground accurately. Especially, groundwater flow in the coastal area is considered to be quite complex that involves density and hydraulic gradient driven flow of freshwater and seawater. In order to understand the behavior of seawater intrusion into freshwater in deep underground, we constructed a laboratory equipment, ‘Mini-MACRO’ (MAss transport Characterization in host ROck). Mini-MACRO consists of three parts: a sandbox (0.5m x 0.25m x 0.1m) and a reservoir tank on each side containing saltwater simulating seawater and freshwater, respectively. Seawater intrusion experiments are conducted using glass beads (sub- millimeter in diameter) and colored saltwater in the sandbox with a transparent face plate to allow visual observation. We created several cases of experimental conditions to observe the seawater intrusion behavior into two-layered stratum against various hydraulic gradients and densities of saltwater resembling the so-called Henry Problem. We confirmed that the results using this equipment match numerical results under simple heterogeneous condition. These results contribute to the better understanding of seawater intrusion behavior and to increasing confidence in modeling methodology of groundwater flow and mass transport in deep underground through comparison with numerical analysis. We believe that it is crucial for the safety assessment of geologic disposal to integrate this knowledge.
DE: 1800 HYDROLOGY
DE: 1805 Computational hydrology
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1894 Instruments and techniques: modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting