日本水文科学会誌
Online ISSN : 1883-7166
Print ISSN : 1342-9612
ISSN-L : 1342-9612
37 巻 , 4 号
選択された号の論文の11件中1~11を表示しています
「日本水文科学会設立20周年記念」 特集号
巻頭言
総説
  • Kimpei ICHIYANAGI
    2007 年 37 巻 4 号 p. 165-185
    発行日: 2007/11/30
    公開日: 2009/03/27
    ジャーナル フリー
    This paper reviews observation- and model-based studies of stable isotopes in precipitation and discusses the Global Network for Isotopes in Precipitation (GNIP) and other regional networks and projects involving isotope observations. Using data from the latest GNIP/Isotope Hydrology Information System (ISOHIS) database, the annual and monthly variabilities of δD-δ18O relationships, the temperature effect, and the amount effect for δ18O were calculated as averages for the Northern Hemisphere, Southern Hemisphere, and globe. At the global scale, the global Meteoric Water Line (MWL) was δD = 8.00 × δ18O + 9.62 (R2 = 0.99), the temperature effect was 0.53‰/°C (R2 = 0.71), and the precipitation amount effect was -1.05‰/100 mm (R2 = 0.20). Comparisons of modeled and observed temperature and amount effects indicate that most General Circulation Models (GCMs) have reproduced the present climate well. This paper also summarizes the use of stable isotopes in precipitation as proxy data for climate variability and water origins, as well as the results of recent isotope-observation studies, especially in the Asian monsoon regions.
  • Reo IKAWA
    2007 年 37 巻 4 号 p. 187-200
    発行日: 2007/11/30
    公開日: 2009/03/27
    ジャーナル フリー
    Stemflow has a significant influence on hydrological and ecological processes within forests. However, research on stemflow is scant as stemflow comprises a very small volume compared to throughfall. In Japan, forest cover mainly distributed in mountainous areas occupies nearly 70% of the total land area and ranges from subalpine to subtropical zones. Many hydrological and agricultural studies have been conducted but a comprehensive literature review that summarizes the generation and chemical characteristics of stemflow is lacking. The purpose of this review is to interpret the results from Japanese forest stemflow papers and to propose objectives for future studies.
  • 佐藤 芳徳
    2007 年 37 巻 4 号 p. 201-208
    発行日: 2007/11/30
    公開日: 2009/03/27
    ジャーナル フリー
    The results of the research on the circulation and the mixing of lake water were organized, and the perspective of the research was considered. The flow of lake water is divided into a horizontal flow and a vertical flow. A horizontal flow is chiefly caused by the wind shear stress. As for the research of the flow caused by the wind shear stress, a field observation, a model flume experiment, and a numerical experiment have been conducted. They provided a remarkable advancement from the 1970s to the 1980s. Hereafter, using a new technology such as GPS will be hoped in the flow observation.
    A vertical circulation is caused by the density difference of water due to the cooling on the lake surface and the wind shear stress. A vertical circulation causes the mixing of lake water. The mixing of lake water is investigated by observing the water quality distribution, especially there are a lot of researches that consider a vertical mixing making use of the profiles of the dissolved oxygen. In a tropical lake, there is a close relationship between the mixing of lake water and the heat balance on the lake surface, then the depth of vertical mixing is estimated by the amount of cooling on the lake surface. Therefore, it is considered that the clarification of the lake water mixing on a tropical lake contributes to the information about the global warming phenomenon. Moreover, some natural lakes are expected as a monitor of acid precipitation and the micro pollutant.
  • Yoshiko IIZUMI
    2007 年 37 巻 4 号 p. 209-220
    発行日: 2007/11/30
    公開日: 2009/03/27
    ジャーナル フリー
    Increasing numbers of studies have recently used stable isotopes of nitrogen (δ15N) and carbon (δ13C) to clarify the source of nutrients in lake water and sediments, the structure and energy flow of food webs, the bioaccumulation and biomagnification of hazardous chemicals in aquatic animals, and temporal trends in lake environments. In lake research in particular, the analysis of δ15N and δ13C is a powerful tool in analyzing the structure of the food web and energy flows, as well as the bioaccumulation and biomagnification of toxic chemicals in aquatic animals. Furthermore, the integration of data on food webs, stable isotope ratios, and environmental geochemistry can be useful in evaluating the risks of exposure to environmental contaminants. It is hoped that further research on lake environments using stable isotopic methods can be performed with the aim of conserving water quality and aquatic ecosystems.
  • 風早 康平, 安原 正也, 高橋 浩, 森川 徳敏, 大和田 道子, 戸崎 裕貴, 浅井 和由
    2007 年 37 巻 4 号 p. 221-252
    発行日: 2007/11/30
    公開日: 2009/03/27
    ジャーナル フリー
     近年, 地下水研究においては, 流動プロセス, 水収支, 起源, 化学反応, 年代などの解明の目的で, トレーサーとしての環境同位体の利用が進み, 多くの手法提案もなされている。環境トレーサーのうちよく利用される1) 酸素・水素同位体, 2) 炭素同位体, 3) 希ガス, 4) 塩素同位体, 5) クロロフルオロカーボン類などについて, その利用手法および有効性についてレビューを行った。
     用いる環境トレーサーが, 反応性のないものであれば, それは地下水が涵養されるときの情報を保持しうる。酸素・水素同位体やd値などは, 涵養の場の特徴応じてそれぞれ固有の値を持つ (標高効果, 内陸効果など) ことが知られているため, 地下水の涵養場の情報を得る上で強力なツールである。含炭素成分は反応性が高いが, 炭素同位体の利用により, その起源を知ることができ, それにより地下水系の中で生じる各種化学反応やガス付加のプロセスについての情報を得ることができる。放射性炭素については, 以前より地下水の年代測定に用いられてきたが, DICの起源について吟味した上で年代結果を論じなければならない。トレーサーとしての希ガスの利用は, その溶解度が温度に依存することから, 涵養時の温度の推定に用いることができる。放射壊変起源の4Heは, 地殻内部で生産され深層地下水系内に蓄積されてゆく。したがって, 4Heの蓄積率がわかれば, 非常に長い滞留時間の推定することができる。放射性塩素は~100万年といった非常に古い地下水の年代測定に用いられる。また, 1950年代に行われた核実験により生成されているため, それをトレーサーにして若い地下水年代にも応用可能である。クロロフルオロカーボン類は, 近年の工業利用により大気中に存在するようになったため, 地下水はその涵養時に溶解する。これらの成分は非常に高感度に濃度の測定ができるため, 若い地下水年代測定や深層地下水系への若い浅層地下水の混入・汚染などに応用される。
     個々のトレーサーを用いた手法は, 非常に簡単な地下水系にのみ適用可能であるため, より複雑な地下水流動系の解明のためには, 複合トレーサーとして各種の成分を扱い, 年代や起源の異なる地下水の混合などのプロセスを明らかにしてゆく必要がある。複合トレーサー利用をした複雑系のシミュレーションによる地下水系の研究は現在, 非常に進展している分野のひとつである。
  • 内田 洋平, 佐倉 保夫
    2007 年 37 巻 4 号 p. 253-269
    発行日: 2007/11/30
    公開日: 2009/03/27
    ジャーナル フリー
    Subsurface thermal regime is affected not only by thermal conduction but also by advection owing to groundwater flow. The effect of thermal advection is especially large in shallow sedimentary layer with active groundwater flow. Subsurface temperature distributions in some basins and plains in Japan are affected by regional groundwater flow systems. Both field observation and simulation results in the study area show that thermal transport conducted by regional groundwater flow system, driven by topographic effect, distorts subsurface temperature distributions. Moreover, subsurface temperature distributions in the Yonezawa Basin and Nagaoka Plain show effect of groundwater pumping. Subsurface temperatures in shallow layers in these areas have seasonal change due to groundwater pumping for snow melting in winter season.
    In recent years, subsurface temperature data have been used for reconstruction of ground surface temperature (GST) history as well. The effects of temperature change at the ground surface in the past have conducted into subsurface and have been recorded as transient temperature perturbations onto the background thermal field. Many studies on GST history in North America and Europe are inferred from inversion of borehole temperature profiles in log data.
    On the other hand, direct utilization of low-temperature geothermal resources, such as geothermal heat pump system, is important from the viewpoint of reduction of CO2 that causes global warming. Such systems are gradually increasing in Japan. To evaluate the influence of direct utilization onto subsurface temperature, an areal simulation, which numerical model was cut out from regional 3D groundwater flow and heat transport model of the Sendai plains, was conducted.
    Subsurface temperature observed with comparative ease includes important clues to understand global environment problems and/or hints for development of new energy to preserve global environment.
    It is hoped that hydrological knowledge contributes to understand many problems in various studies with subsurface temperature.
  • 林 武司, 宮越 昭暢, 安原 正也
    2007 年 37 巻 4 号 p. 271-285
    発行日: 2007/11/30
    公開日: 2009/03/27
    ジャーナル フリー
    Urbanization affects quantitatively and qualitatively groundwater environment in urban area. Especially, groundwater environment in large urban area has been changed more than several decades. However, there are few studies about evaluation of secular change of groundwater environment with developing of urban area. In this study, long term change of groundwater environment in the Kanto plain and the Nobi plain which had the very large urban areas were summarized from the view point of regional groundwater flow.
    Present groundwater flows in these plains were significantly different from the groundwater flows in the periods when the effects of urbanization were small, even though more than 30 years have passed since groundwater extraction had been regulated. Also, three dimensional distributions of chemical properties of groundwater quality and environmental isotopes have changed. These results show that the effects of human activities were still strongly remained. On the other hand, demands for groundwater for public use and private use have become increasing in recent years because of recovery of hydraulic potentials of confined aquifers that had depleted from the 1950s to 1970s by huge amount of groundwater abstraction. Therefore, it is important to keep monitoring and evaluating the groundwater environment in these urban areas for sustainable management of groundwater resources.
  • 井岡 聖一郎, 岩月 輝希, 酒井 利彰, 石島 洋二
    2007 年 37 巻 4 号 p. 287-293
    発行日: 2007/11/30
    公開日: 2009/03/27
    ジャーナル フリー
    Redox potential (Eh) is one of the most important physico-chemical properties of groundwater. Groundwater Eh have been studied in terms of safety of high-level radioactive waste disposals, water resource management and so on. As the results, it is getting clear that redox potential of deep groundwater in sedimentary and crystalline rocks have a remarkable variability. For example, some reported Eh values of deep groundwater decrease with increasing depth, i.e. with residence time. However, there are few reports showing data measured in situ. Only some Eh values of deep groundwater measured from research borehole drilled at crystalline rocks in Japan and Sweden have been reported. Between 200 and 1000m depth, the Eh values of the deep groundwater range from about 0 to -400mV.
    This essay first briefly summarizes methodology for Eh measurement and reports Eh values of deep groundwater. Then, it discusses the remaining issues of Eh measurement that are to develop of measurement technology applicable for various geological environments and to understand the redox evolution process through the groundwater flow system.
  • Noboru HIDA
    2007 年 37 巻 4 号 p. 295-302
    発行日: 2007/11/30
    公開日: 2009/03/27
    ジャーナル フリー
    In this paper, the author reviews the present situation of basin artificial recharge of ground water (MAR: managed aquifer recharge) as of 2007 in Japan. Most of the artificial recharge of basin method is carried out using alluvial fans. The enhancing groundwater resources in the Rokugo alluvial aquifer has resulted in sustainability for the groundwater environment, especially in the distal fan. As a general judgment, the basin artificial recharge contributes to sustainable aquifer management in alluvium. As a result of this review, the basin artificial recharge will be utilized more in the future, not only in Japan, but in monsoon Asian countries as well.
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