Free Flow

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Transboundary W ater M anagement
City, two local governments and the large groundwater
users in the city areas to support the funding system.
Each year the Kumamoto Prefecture, Kumamoto City
and two local governments together with JA discuss
development initiatives and the preservation of
groundwater resources in the region. During the six
years 2004-20096 the system increased the recharged
area of abandoned paddy fields from 255 hectares per
month to around 550 hectares per month, while esti-
mated groundwater recharge amounts increased from
8.73 million m3/year to 16.77 million m3/year. As a
result, the spring discharge rate in Lake Ezu, which is
located in the discharge area of the groundwater flow
system in the Kumamoto region, has recovered to a
level of around 12 years before.
Accepting those fruitful effects of the system for
groundwater recharge, the Kumamoto Prefecture and
13 local governments made a long-term groundwater
management plan in 2008, for which the target year
is 2024. According to a report by Kumamoto City, the
target groundwater recharge amount in 2024 has been
set at 73 million m3/year, with reduced groundwa-
ter withdrawals set at 16 million m3/year. This target
groundwater recharge amount for the Kumamoto
Artificial groundwater recharge through an abandoned rice paddy field (left: before flooding, right: after flooding)
Conference on Utilizing Rice Paddies for Groundwater
Recharge in the Kumamoto region
Conference on Utilizing Rice Paddies
for Groundwater Recharge
(Consisting of Kumamoto Pref.,
Kumamoto City, relevant two local
governments, four local land improving
districts and JA)
Kumamoto
City
Corporative
farmers
Conf. on Proc Agricul.
of Water Cycle Type
(Relevant two local
governments, four local
land improving
districts and JA)
Effective recharge to groundwater reservoir
Proceeding and adjustment
of the project
Discharge Recharge
Financial
support
Financial
support
Make an
application
and report
Make an
application
Source: T. Tanaka