SUBSURFACE DAM FOR WATER RESOURCES DEVELOPMENT IN MIYAKO ISLAND,OKINAWA PREFECTURE, JAPAN

A “Subsurface Dam” can be described as an artificial reservoir storing underground water in the porous spaces of stones, by a cut off wall being constructed in geological strata. The construction of subsurface dams in a southern island of Okinawa Prefecture, Miyakojima, Japan, was the life-giving reservoir project using the latest new technology at that time for water resources development under the fertile soil. In this paper the concept of the subsurface dams of Miyakojima, the construction methods, and other related issues are presented.