Paddy Field Characteristics in Water Use: Experience in Asia - Water and Agriculture: Sustainability, Markets and Policies - page 232

The local government of Ishikawa prefecture of Japan carried out a long term
monitoring and research on groundwater level in the Tedori River Basin from the 1970s
to 2000. The research report concluded that the groundwater level decreased during non-
irrigation periods when the water supply is cut off to paddy fields. Figure 23 shows the
monthly change of the amount of water discharged by pump and that of groundwater
level in the Tedori River Basin. The report also concluded that the diminishing area of
cultivated paddy fields over the long term caused the gradual decrease in groundwater
level and deterioration of groundwater resources from year to year. Figure 24 shows the
secular change in area of arable paddy fields and groundwater level in the Tedori River
Basin.

Figure 23. Monthly change of amount of water discharged by pump and ground water level
in Tedori River Basin, Japan

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Figure 24. Secular change in area of arable paddy field and ground water level
in Tedori River Basin, Japan