Irrigation Systems in Japan

Tabayashi, Akira

doi:10.4157/grj1984b.60.41

Cited by 15 publications

(3 citation statements)

References 20 publications

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“…The Nasunogahara alluvial fan in central Japan was formed by the Naka, Sabi, Kuma, and Houki rivers, which flow out of the mountainous region to the northwest of the fan (Figure 1). The alluvial fan extends over an area of approximately 400 km 2 and is bounded by the Naka River along its eastern edge and the Houki River along its western edge. The flow in the upper reaches of the Sabi and Kuma rivers is usually underground, but these rivers emerge above ground in the central part of the fan and join the Houki River in the toe of the fan.…”

Section: Location Land Use and Water Usementioning

confidence: 99%

“…Vast paddy rice fields are situated on alluvial fans, which occupy more than half (54%) of Japan's lowland area [1]. River water is usually diverted at the apexes of such alluvial fans and then delivered through a network of irrigation canals to each paddy rice field by gravity [2]. Alluvial fans are also vital aquifer systems that support local agricultural, industrial, and socio-economic development worldwide, wherever groundwater is utilized as an important water resource [3].…”

Section: Introductionmentioning

confidence: 99%

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Application of a Self-Organizing Map of Isotopic and Chemical Data for the Identification of Groundwater Recharge Sources in Nasunogahara Alluvial Fan, Japan

Tsuchihara

Shirahata

Ishida

et al. 2020

Water

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Paddy rice fields on an alluvial fan not only use groundwater for irrigation but also play an important role as groundwater recharge sources. In this study, we investigated the spatial distribution of isotopic and hydrochemical compositions of groundwater in the Nasunogahara alluvial fan in Japan and applied a self-organizing map (SOM) to characterize the groundwater. The SOM assisted with the hydrochemical and isotopic interpretation of the groundwater in the fan, and clearly classified the groundwater into four groups reflecting the different origins. Two groundwater groups with lower isotopic ratios of water than the mean precipitation values in the fan were influenced by the infiltration of river water flowing from higher areas in the catchments and were differentiated from each other by their Na+ and Cl− concentrations. A groundwater group with higher isotopic ratios was influenced by the infiltration of paddy irrigation water that had experienced evaporative isotopic enrichment. Groundwater in the fourth group, which was distributed in the upstream area of the fan where dairy farms dominated, showed little influence of recharge waters from paddy rice fields. The findings of this study will contribute to proper management of the groundwater resources in the fan.

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Section: Location Land Use and Water Usementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of a Self-Organizing Map of Isotopic and Chemical Data for the Identification of Groundwater Recharge Sources in Nasunogahara Alluvial Fan, Japan

Tsuchihara

Shirahata

Ishida

et al. 2020

Water

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“…In the study of agricultural region, the regional differences in Japanese irrigation systems were studied by GOMI (1983) and TABAYASHI (1981TABAYASHI ( , 1987. GOMI (1983) attempted to classify river basins based on the data of supply sources for irrigation water.…”

Section: Obtained Through Hydro Geographical Studiesmentioning

confidence: 99%

Recent Trends in Hydro-geographical Studies in Japan

Shimmi

Suzuki

Hida

1988

Geogr. Rev. Jpn, Ser B

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The purpose of this paper are to show the recent trend of hydro-geographical studies in Japan dealing with the hydrological environment and the relationship between water and man, and to discuss problems for future study. At the regional level, the subjects studied are the water balance and the hydrological environment in Japan. Concerning water utilization, the following themes were discussed: water resources development and water problems during the period of rapid economic growth, establishment and development of a public supply system for industrial water, and changes in irrigation water use due to rapid urbanization. In the case of the basin scale, a number of studies on groundwater were conducted. The subjects studied are the unique systems of water use such as manbo, snow meltig system using groundwater, environmental problems due to water use, and groundwater management. Concerning the relationship between water and urbanization, many case studies were made on the following subjects: changes in water use, historical develooment of water transfer, abandonment of irrigation ponds, as well as the hydrological environment and water use in urbanized areas. Other interests are focused on such themes as floods and flood hazard, social problems related to dam construction, and problems specific to water on islands. There are many investigations relating to water and man in the different fields of geography. The geographical information available through this basic research, however, is not summarized comprehensively from the hydro-geographical viewpoint. For future study, it is very important to develop methods of expression for the hydrological environment and water use, to attempt to describe hydro-geography based on the concepts of the hydrologic cycle and water balance, and to publish a reliable manual on hydro-geography.

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