Paddy Field Characteristics in Water Use: Experience in Asia - Water and Agriculture: Sustainability, Markets and Policies - page 225

Figure 13. Component ratio of return flow from agricultural land in the diverted flow discharge at each
diversion work
(by year, average for an irrigation period)

50

1983 1987

40

1984 1988

1985 1989

30

1986 1990

20

Average in 1983-1990

10

0

Shimobuchi Oda Fujisaki Iwade Shinrokka

Figure 14. Irrigation water re-use ratio (%) at each diversion work
(by year, average for an irrigation period)

50

1983 1987

40

1984 1988

1985 1989

30

1986 1990

20

Average in 1983-1990

10

0

Shimobuchi Oda Fujisaki Iwade Shinrokka

Figure 15 shows the ￿￿ ￿￿ ￿￿ Iwade D.W. from June to September in

a dry year, 1987. ￿￿￿￿ ￿￿ ￿￿￿￿￿ ￿￿￿! ￿￿

respectively after a dry spell. Figure 16 shows the transition of river flow and its
￿￿￿ ￿￿ ￿￿

Iwade D.W. from June 20 to July 1 in 1987. It
indicates that the return flow from upstream agricultural land ( ) and return flow of

water irrigated in the upstream farmland ( ) plays a very important role for stabilising

the river flow during the dry period.