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close this bookFreshwater Resources in Arid Lands (UNU, 1997, 94 p.)
close this folder5: The development of groundwater resources on the Miyakojima Islands
View the document(introduction...)
View the documentIntroduction
View the documentOutline of the Miyakojima Islands
View the documentGeology and the hydrological cycle
View the documentOutline of the irrigation project on Miyakojima
View the documentThe construction and concept of the underground dam
View the documentThe Construction of the Cut-off Walls
View the documentThe construction of the intake facilities
View the documentThe storage situation of the Sunagawa underground dam
View the documentConclusion
View the documentBibliography


An estimation of potential and available groundwater resources is very difficult because of their invisibility. In the case of the construction of underground dams that store the groundwater How, we need to consider many technical issues. Since 1990, on the Miyakojima Islands, the Japan Agricultural Land Development Agency (JALDA) has been implementing a project to construct two underground dams that will be the largest in the world. One of the two was completed in November 1993 and the other is now under construction. This report presents the concept of the underground dams on the Miyakojima Islands, the construction methods, and related technical issues.