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Returning Groundwater
to the Earth. Protecting Water Resources
Groundwater Recharge for
a Sustainable Society
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| Sony
Semiconductor Kyushu Corporation Kumamoto Technology
Center |
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| Kumamoto
is blessed with extensive groundwater resources,
and is one of the few cities in Japan referred
to as a "city of water". Recently
however, the reduction in the volume of that
groundwater has become a serious concern. It
is an invaluable natural resource. As one member
of the community who takes advantage of this
resource, the Kumamoto Technology Center, in
cooperation with environmental NGOs, farmers,
and local government, is now working on improving
groundwater recharge using irrigated rice fields.
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Downward Trend Associated with Reduced Rice
Acreage Policies and Conversion to Residential
Use
The Kumamoto area centered around Kumamoto City
has such rich groundwater resources that essentially
100% of its drinking and residential water supply
is provided by groundwater. The main source
of this groundwater is water that permeates
into the soil from rice fields in the middle
reaches of the Shirakawa river; 200 million
tons of groundwater is pumped every year. The
reduction of the capacity of the region to recharge
the groundwater, due to reductions in the rice
acreage planted and increasing conversion of
farmland to residential use, is causing a rapid
reduction in the amount of this crucial natural
resource. Starting in 2003, the Sony Semiconductor
Kyushu Corporation Kumamoto Technology Center
has begun recharging this groundwater as its
responsibility of a company that uses large
amounts of water in its semiconductor manufacturing
operations.
Immediate Response to Calls from NGO Members
The impetus for the start
of these efforts came from calls from members
of an environmental NGO. When the Kumamoto Technology
Center was founded, members of the local Kumamoto
environmental NGO "Environment Network
Kumamoto" published an open letter to Sony
on the Internet titled "Concerning the
Environmental Burden of the New Factory"
and Sony responded. Given this background, Sony
Semiconductor invited members of that NGO to
the Sony "Environment Month Kickoff Ceremony"
and asked them to present a talk. At that time,
the NGO invited Sony to join a partnership and
to join the NGO in activities to protect the
groundwater. The former president of Sony Semiconductor
Kyushu Corporation, Mr. Hamasaki, accepted that
invitation to work together and started investigating
concrete means for groundwater recharge.
Achievement of Greater than Expected Recharge
Groundwater recharge was implemented
through two methods. The first was to increase
infiltration groundwater recharge by diverting
water from the Shirakawa river to rice fields
that were not being used for growing rice due
to the (government policy of) reductions in
the acreage planted. The second was to also
divert water from the Shirakawa river to fields
that are still used for rice production after
the fall harvest was completed. Based on a policy
of return of an amount corresponding to the
approximately 800,000 tons of water used by
the Kumamoto Technology Center, Sony calculated
the required area from the infiltration depth
(the depth to which water infiltrates in one
day). Sony then implemented this groundwater
recharge over a total rice field area of 30
hectares (about six times the area of the Tokyo
Dome sports area). Since the results achieved
exceeded the originally expected infiltration
depth (10 cm)*, this project achieved a greater
groundwater recharge than originally planned.
At the same time as continuing this groundwater
recharge project, Sony is actively pursuing
environmental protection efforts, such as reducing
the amount of water used, at all its technology
centers including the Kumamoto Technology Center.
*: According to a survey performed
by Professor Ichikawa of Kyushu Tokai University
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| Main Points of this Water
Recharge Effort |
# It is possible for Sony's Kumamoto Technology
Center to be environmentally neutral (with
usage and recharge in balance) by returning
to the aquifer an amount equivalent to the
amount used by the center.
# The significance and importance of Sony
Semiconductor Kyushu Corporation's groundwater
recharge project have been widely recognized
and it has been a stimulus for other groundwater
recharge efforts.
# This was not an independent effort by Sony
Semiconductor Kyushu Corporation, but rather
was a joint effort by local government, local
groups, environmental NGO, and Sony.
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| Concrete Policies |
1. Flooding rice fields
that are the object of reduced rice acreage
policies with water in the summer (mid June
to mid July) Recharging is performed before
fields not used for rice due to reduced rice
acreage policies are used for other crops such
as carrots.
2. Flooding rice fields that are used for growing
rice with water after the harvest (late October
to late November) Recharging is performed after
harvest of rice, which uses organic fertilizers,
but before planting of off-season crops.
Cooperating organizations: Shirakawa
River Middle Reaches Improvement Committee,
JA Kikuchi Kikuyo Office |
| Current
Status of Kumamoto Groundwater |
The recharge amount is
falling rapidly
According to studies by Kumamoto City and Kumamoto
Prefecture, whereas the recharge amount in 1990
was 705.5 million tons, that had fallen to 690
million tons in 2000. This is expected to fall
to 660 million tons by 2010.
Groundwater overextraction status
According to the 1990 study, the amount of groundwater
influx (recharge) was 705.5 million tons. Since
the amount of outflow was 718.1 million tons,
the difference is an net loss of 12.6 million
tons: the balance was in the red.
Reduction in recharge land
Due to the policy of reduced rice acreage, the
rice fields in the towns of Kikuyo and Otsu
that function for groundwater recharge fell
by about 25% for the two towns. |
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Groundwater Recharge
Structure Using Irrigated Rice Fields
Reminded Anew
of the Importance of Groundwater |
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Shoichi Mizoguchi
Sony Semiconductor
Kyushu Corporation Environmental Strategy
Dept. |
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When we began studying concrete approaches with
the members of the Environmental Network Kumamoto
group, the first proposal we received was for
local production/local consumption, that is,
products produced in an area should be consumed
or used in that area. We contracted with local
farmers who accepted that we would flood the
rice fields after the rice grown with organic
fertilizers was harvested, and Sony Semiconductor
Kyushu Corporation purchased that rice for use
in the Kumamoto Technology Center employee dining
hall. We had the contracted farmers use organic
fertilizer and added the cost of flooding the
rice fields to the usual cost of organically
grown rice. These costs were paid by Sony Semiconductor
Kyushu Corporation. I thought that this was
an excellent plan, and immediately contacted
JA (the Japanese nationwide agricultural organization)
and obtained their cooperation. However the
number of farmers who were using organic farming
was still quite small. Furthermore, after the
rice harvest, some rice fields were used for
other crops such as carrots, and the period
that the rice fields could be used for groundwater
recharging was limited to one month out of the
year. As a result, this approach could not achieve
the groundwater recharging goal of 800,000 tons.
While wondering what could be done, I learned
from an NGO member that the Shirakawa River
Middle Reaches Improvement Committee had established
a groundwater recharging plan for locations
not used for rice cultivation whose main purpose
was control of harmful insects. By covering
part of the costs of that plan, Sony Semiconductor
Kyushu Corporation was able to acquire the target
groundwater recharging area required. I feel
that during this project, all of us, the NGO
members, local government, and JA, were able
to forge excellent cooperative relationships.
Through these efforts, I became more strongly
aware of the importance of groundwater for the
future. We must not be satisfied with merely
recharging by the amount we have used, but Sony
Semiconductor Kyushu Corporation as a whole
must continue to strive to reduce the amount
of water used. Just as people who live in Oze,
a region blessed with a rich natural environment
(and famous for it's wild aquatic plants), would
think it only naturally that they should protect
Oze's environment, we also must, as users of
the Kumamoto groundwater resource, work to protect
this region's environment. |
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See all articles with
figures and tables. 
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Vol.35 |
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