泥炭の水理特性を反映した地下水流動モデル  [in Japanese] Groundwater Flow Model Considering Hydraulic Properties of Peat  [in Japanese]

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Abstract

泥炭の水理特性は深度によって異なっていることが知られている.従来,泥炭地定点での地下水位変動は泥炭の性質と関連させてタンクモデルを援用する方法によって解析され,良い結果を得てきた.しかしこの方法を広域に適用するには,地点ごとに異なるパラメータの取り扱いなど解決すべき点が多い.一方,広域の地下水流動計算にはダルシー則によった運動方程式と連続方程式に基づく方法が多用されてきたが,泥炭の性質が正確に反映されていない場合があった.本研究では観測した降雨と地下水位の変動記録に基づき,泥炭地の空隙率や透水係数などの水理学的特性を定式化した.ついで従来のダルシー則に基づいた方法と,本稿で提案する泥炭の水理学的性質を考慮した方法によって自由地下水の二次元流動計算を行なった.その結果透水量係数と同じ次元をもつパラメータを地下水位深度の指数関数で表わすことにより観測結果をよく再現できることがわかった.

The hydraulic properties of peat are well known to be different depending on the depth from the ground surface. Conventionally, the groundwater movement in a fixed point on peatland has been analyzed by the method of Tank Model, for instance, and has attained fairy good results. However, when we need to apply this method to the extensive area, there are issues of solving a vast number of parameters to be determined at each point. Using the motion equitation based on the Darcy's law and the continuity equation is another conventional solution for calculating the groundwater flow in extensive area, but the properties of peat is scarcely reflected to this model. In this study, first we formulated the hydraulic properties of peat such as porosity and permeability from the observed fluctuations of groundwater table and amount of rainfall. Then we carried two-dimensional flow model for unconfined groundwater in two methods. One is conventional method based on Darcy's law, and the other is proposed method considering hydraulic properties of peat. By using newly defined T-parameter, which has homogeneous element with the coefficient of transmissivity, the peat hydraulic properties have been represented as the factor of depth, and this derived good result in simulation of groundwater fluctuations in the latter method.

Journal

  • Wetland research

    Wetland research 1(0), 3-15, 2010

    Japan Wetland Society

Codes

  • NII Article ID (NAID)
    130007622473
  • Text Lang
    JPN
  • ISSN
    2185-4238
  • NDL Article ID
    023977343
  • NDL Call No.
    Z74-G899
  • Data Source
    NDL  J-STAGE 
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