地下水学会誌
Online ISSN : 2185-5943
Print ISSN : 0913-4182
ISSN-L : 0913-4182
35 巻, 3 号
選択された号の論文の8件中1~8を表示しています
  • 井内 国光, 中山 祐輔, 柿沼 忠男
    1993 年 35 巻 3 号 p. 157-163
    発行日: 1993/10/18
    公開日: 2012/12/11
    ジャーナル フリー
    Various water qualities, especially stable isotope ratios, of groundwater in shallow wells were measured, together with groundwater levels, in Gogo Island, Ehime Prefecture.
    In a coastal region of the Yura district, chloride ion concentration far greater than 200mg·1-1 (the standard value of city water) was always found and the δD versus δ18O diagram suggests that the groundwater in this region is a mixture of seawater and upstream groundwater.
    Non-dimensional values of δD, δ18O and Cl- of groundwater near the bottom of a well in a coastal region of the Yura district indicate almost the same value, and it was estimated that groundwater contained approximately 20% seawater. The vertical distribution of non-dimensional Cl- is different from those of δD or δ18O. The former indicates higher concentration in the upper part of the well. The higher concentration may be caused by the Cl source except seawater, e. g. fertilizer.
  • -水質と222Rn濃度を指標とした地下水と渓流水の交流解析-
    今泉 眞之, 濱田 浩正, 金子 文宜, 奥山 武彦, 小前 隆美
    1993 年 35 巻 3 号 p. 165-183
    発行日: 1993/10/18
    公開日: 2012/12/11
    ジャーナル フリー
    222Rn is an inert, naturally occurring, radioactive gas. The source of 222Rn in groundwater is 226Ra which is ubiquitous in sediments and sedimentary rocks, incorporated in aquifer material. As the 226Ra decays, its daughter product, 222Rn, diffuses into the pore waters of rock formations and becomes concentrated in the aqueous phase. Because 222Rn is present in much higher concentrations in groundwater than surface flow, anomalously high concentrations detected in a stream can be indicative of the influx of groundwater to surface flow.
    Volumes of stream flow were measured and water samples of stream were systematically collected for analysis of chemical compositions and 222Rn concentrations at nineteen locations along the stream in a small watershed of landslide area in Kyonan City, Chiba prefecture. Sevevteen samples of branches and springs were also collected.
    Two types of groundwater, the shallow groundwater and the deep groundwater, have been identified, clearly defined on the (Ca2+ + Mg2+) -HCO3 daiagram. The chemical compositions of streamwater and branch water are the intermediate compositions between two types on the diagram.
    Based on the fact of the change of chemical compositions, discharge volume and concentration of 222Rn in stream water, we found several possible groundwater seepage points along the river.
    The geochemical evolution of the streamwater along the river course presents a gradual increase in Mg2+, Ca2+, HCO3-, SO42-, K+ and PO4-P and a relative decrease in NO3-N, and Si. However, there are step changes at mixing points of branch water and groundwater with streamwater.
    From the present results, it is concluded that the compositions of streamwater are initially originate from shallow groundwater and are modified along the river course, mainly due to the mixing of branche water and deep groundwater, then yielding the range of deep groundwater compositions.
    222Rn data can also be used in a simple mass-balance equation in conjunction with stream discharge data to quantify groundwater inputs to surface discharge in stream.
  • 本島 勲
    1993 年 35 巻 3 号 p. 185-200
    発行日: 1993/10/18
    公開日: 2012/12/11
    ジャーナル フリー
    In this paper, a method for analysis on some characteristic features and residence time of groundwater in bedrock using isotopes of oxygen(18O), hydrogen(D, 3H) and radon(222Rn) were examined.
    And on the basis of these examinations, some characteristic features and residence time of groundwater around the underground caverns located in the Central and Kantoh areas in Japan were investigated.
    Main results obtaind from this investigation are summarized as follows;
    1) Isotopic composition of groundwater proves that the groundwater around underground cavern contains some amount of fresh groundwater through the unsaturated zone.
    2) On the basis of the examination using hydrogen isotope(3H), the discharge water into the caverns cntained 10-20 % of old groundwater of which the age was calculated as about 20 years.
  • 馬原 保典, 五十嵐 敏文, 田中 靖治
    1993 年 35 巻 3 号 p. 201-215
    発行日: 1993/10/18
    公開日: 2012/12/11
    ジャーナル フリー
    This study focused on developing a tritium and helium -3(3H-3He) dating method to survey the flow of groundwater in a large geohydrologic catchment area with groundwater basins including candidate disposal sites for wastes. The dating method is based on counting the increase of 3He produced by beta decay of tritium in groundwater. Precise detection of 3He is very difficult because the ratio of 3He to 4He is generally less than 10-6 for 10-8 ccSTP of helium dissolved in one gram of groundwater. We developed an isolating sampling method for groundwater in which atmospheric air is prevented from contacting groundwater sample and the 3He is measured by mass spectrometry. We applied this dating method to the confined aquifer in the Mishima lava flow located in the east side of Mt. Fuji. The measured age of groundwater is aligned young to old following the groundwater flow. The groundwater in the Mishima area was grouped into two different sources based on the measured groundwater ages and the stable isotope composition (δD and δ18O). The movement of groundwater in the lava flow was calculated to be an approximate 16m/day based on the difference between the groundwater ages measured at two sampling sites (Izushimada and Kakitagawa) and the geographical distance. This is in good agreement with results measured by radioisotope flow meter in a geohydrologic investigation 20 years ago and calculated by Darcy's law.
  • 竹田 信
    1993 年 35 巻 3 号 p. 217-225
    発行日: 1993/10/18
    公開日: 2012/12/11
    ジャーナル フリー
    It is expected that permeable dune sand areas have high potential of recharge to groundwater. The purpose of this paper is to clarify the soil moisture movement mechanism in unsaturated zone on the bare soil surface site on the Syounai Dune area. Actual evaporation duringll fine weather days was about 5-26% of the Penman potential evapo-transpiration. Evaporation experiment indicated that the thickening of dry sand layer restricted evaporation. As the result that the dry sand layer restrained evaporation, we could expect that the amount of recharge in the sand dune area increased relatively.
  • 4.2ボーリング調査と検層法
    上田 敏雄
    1993 年 35 巻 3 号 p. 227-246
    発行日: 1993/10/18
    公開日: 2012/12/11
    ジャーナル フリー
  • 5.1 単孔式現場透水試験
    平田 洋一
    1993 年 35 巻 3 号 p. 247-254
    発行日: 1993/10/18
    公開日: 2012/12/11
    ジャーナル フリー
  • -大野盆地の湧水群-御清水
    高村 弘毅, 河野 忠
    1993 年 35 巻 3 号 p. 255-261_1
    発行日: 1993/10/18
    公開日: 2012/12/11
    ジャーナル フリー
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