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WATER COOPERATION, SUSTAINABILITY AND POVERTY ERADICATIONBasin-wide groundwater management using the system ofnature in Kumamoto City, JapanThis has been the case in Kumamoto City in the centre of Kyushu,the southern major island of Japan. In cooperation with neighbouringmunicipalities, Kumamoto City government has managed anartificial groundwater recharge system using abandoned paddies andprotected watershed forests. Drinking water for the city’s 730,000citizens is totally supplied by this abundant groundwater, whichis chlorinated only at a minimum level without further purification.By protecting the natural systems and conserving Kumamoto’shigh-quality groundwater, the city can provide its citizens with highquality ‘mineral water from the tap’.The city has undertaken various efforts to maintain its abundant,pure and crystal-clean groundwater so it can pass down this treasureto future generations. Between 90,000 and 270,000 years ago, thevolcanic Mount Aso experienced four violent eruptions with pyroclasticflows. These flows deposited and accumulated to more than100 metres in thickness, and became an ideal groundwater aquiferfor the region. In addition, about 400 years ago, Kato Kiyomasa, thefeudal lord of Higo (now Kumamoto), promoted the developmentof paddy fields along the Shira river alluvial low land, where it iseasy to permeate and recharge the local groundwater aquifer. Thissituation worked well and allowed Kumamoto access to a far greateramount of clean groundwater. Kumamoto City does not have analternative source for groundwater, and can face a crisis when theresource dries up or is polluted. With rapid urbanization since theearly 1970s, the amount of percolated groundwater has decreasedwhile water use has increased.Kumamoto has carried out various initiatives to conserve itsgroundwater, including the adoption of the Declaration of theGroundwater Preservation City in 1976 and the installation ofgroundwater observation wells in 1986. As part of these efforts,the city has conducted research on groundwater flow systemsin the area and identified a trend towards long-term decreasesin groundwater levels. This was mainly due to the decrease inPaddy fields along the Shira river helped to recharge Kumamoto City’s localgroundwater aquiferImage: Kumamoto City, Japangroundwater recharge, which was mostly caused bychanges in land use in the recharge area over the past30 years. The decline in groundwater recharge levelsfrom paddy fields was due to the practice of convertingpaddy fields to dry fields, and this accelerated the fallin groundwater levels.As a result, the city saw that it needed to cooperatewith neighbouring municipalities in order to conservegroundwater. To tackle issues that cannot be solvedwithin one administrative district or one municipalityalone, cooperation with concerned adjacentmunicipalities is indispensable. The city formulatedan agreement to maintain and increase groundwaterrecharge through cross-municipal cooperation. Majorcooperative initiatives started in 2004, includinga project to flood the converted paddy fields of theShirakawa river mid-basin and to maintain the watershedprotection forests in the upper basin.Cooperation on the project to flood the paddyfields was carried out through the Council forSustainable Water Use in Agriculture, which consistsof Kumamoto City, Ozu and Kikuyo towns, fourlocal agricultural land improvement districts, JapanAgricultural Cooperatives (JA) Kikuchi and JAKumamoto City East Branch. The project providessubsidies to encourage farmers to flood theirconverted paddy fields with water from the Shirakawariver every day for one to three months between Mayand October. Farmers may flood their fields afterharvesting and before planting and growing crops.The amount of subsidies depends on the length ofthe flooding period. The flooding is effective notonly to recharge groundwater levels, but also to limitthe negative effects of weeds, insects, diseases andcontinuous cropping issues. Moreover, flooding helpsto reduce the use of agricultural chemicals, preventsgroundwater pollution and reduces financial costs.Important watershed forests, which are vital toKumamoto City, are located in the upper basins of thePromoting cooperation in Bogota, ColombiaThe Río Bogotá is highly polluted. The project focused onthis issue and specifically preventing pollution by smallscaleand informal sector tanneries on the upper part ofriver. Key players, including an association of tanners,the environmental regulator, local government, an NGO, auniversity and the Chamber of Commerce, were engagedthroughout the project.The Sustainable Water Management ImprovesTomorrow’s Cities’ Health project of the United Nationssupported a process of conflict resolution, capacity buildingand dialogue, and the regulator is now pursuing thesealternatives to a punitive, legalistic and failing approach.Almost half of the informal small enterprises that werepolluting have now implemented cleaner productionprinciples, thereby removing much of their pollution.This has also led to an increase in their productivity. Theresearch supported the tanners in making changes and afollow-up project is now expanding this approach across awider catchment area. 2[ 193 ]