Journal of Groundwater Hydrology
Online ISSN : 2185-5943
Print ISSN : 0913-4182
ISSN-L : 0913-4182
Volume 49, Issue 4
Displaying 1-4 of 4 articles from this issue
  • Masaru TOIDA, Mayumi TANAKA, Satoshi NAGAI, Takehiko SUZUKI, Mitsuyosh ...
    2007 Volume 49 Issue 4 Pages 291-307
    Published: November 30, 2007
    Released on J-STAGE: December 11, 2012
    JOURNAL FREE ACCESS
    Groundwater flow velocity in deep geolog ical formation is estimated in the range of 10-10-10-8m/s of which lowest case is several orders of magnitude less than that measured by the conventional techniques. The situation implies the underestimation of the confinement performance of the geosphere particularly for the radioactive waste disposal. The objective of this study is thus to propose the flow rate measurement method in the deep geologic environment by using a new concept; the solid particle tracer coupled with the ultrasonic detection sensors which are installed in a single borehole. The system enables to measure the flow vector in the range of 10-10-10-5m/s and the performance of this new system has been validated by both the laboratory tests and insitu measurements.
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  • Masaru TOIDA, Mayumi TANAKA, Eiko SUGIMOTO, Tomoyuki HISHIYA, Makoto N ...
    2007 Volume 49 Issue 4 Pages 309-326
    Published: November 30, 2007
    Released on J-STAGE: December 11, 2012
    JOURNAL FREE ACCESS
    The groundwater flow velocity at deep u n derground is expected as low as 10-10-10-8mis that is several orders of magnitude lower than the detection limit of conventional measurement techniques. The authors have developed a new technique to measure such a low flow velocity by using solid particle tracer coupled with ultrasonic sensors in a single borehole sectioned by a double packer system. The 3-D groundwater flow measurement system has been designed to estimate the flow in the surrounding rock medium from the data obtained in a borehole. To establish the design, the disturbance due to the presence of the devices in the measuring rod was examined by numerical analyses. The results indicated the disturbance was minimized and eliminated when the focus area (ca. 1cm3) of the ultrasonic sensors was set at the vicinity of the center of the borehole. Based on the results of numerical analyses, a proto-type vector seepage probe was fabricated and applied in the laboratory for verification. As the results, a wide range of water flow velocity 10-9-10-5m/s could be detected by the set-up of the proposed measurement system and the estimation method of groundwater flow in a measurement area was verificated.
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  • Isao MACHIDA, Kazuhiro ITADERA, Kazutaka MANNEN
    2007 Volume 49 Issue 4 Pages 327-339
    Published: November 30, 2007
    Released on J-STAGE: December 11, 2012
    JOURNAL FREE ACCESS
    This study determines the source areas o f the heat and chemical components at a hot spring from a hydrological viewpoint. The study area, in the Gora region of Hakone, Kanagawa Prefecture, is one of the most famous hot spring resorts in Japan, locates upon the northeastern slope of the central cone of Hakone Caldera. High-temperature NaCl-bearing water -the presence of NaCl is one of the representative chemical properties of hot springs in this region- is formed by the mixing of groundwater with magma-derived thermal fluid (Oki and Hirano,1970).
    The spatial distribution of the hydraulic head to a depth of several hundred meters was estimated using measurement data collected from 1960 to 2000. The data reveal that the groundwater flow has a downward component. The high-temperature NaCl water shows a WNWESE zonal distribution that does not correspond to the direction of groundwater flow and does not related to the boundary of the hydrological basin. It is therefore concluded that this zone is the source area of the heat and chemical components of the hot spring. The Gora region lies within a stress field marked by NESW extension; therefore, the source area is inferred to have formed under the influence of tectonic stress.
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  • Kazuyoshi ASAI, Mamoru YASUDA, Yasuo SHIMANO
    2007 Volume 49 Issue 4 Pages 341-353
    Published: November 30, 2007
    Released on J-STAGE: December 11, 2012
    JOURNAL FREE ACCESS
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