Today I am heading for a tour at the Miyakojima City Underground Dam Museum in the Fukuzato, Gusukube.
I was lost, and there was a signboard.
I got a little more lost and finally arrived. It is a strangely large, fairly large facility.
It is a general view of the facility. It is integrated with a large park and other facilities.
When entering the facility for an entrance fee of 300 yen, there was a movable model of Miyakojima. The staff spoke to me and explained the mechanism of the underground dam while manipulating the model.
As Miyako's climate is subtropical, it has a lot of rain, but people of old times were plagued by drought and had a harsh agricultural environment. The reason is that because the underground stratum is easy to pour water, the rainwater does not remain on the surface of the soil and soaks deep into the ground, and flows from the end of the island to the sea.
Not only that, it is said that because the sunlight is strong, most of the water remaining on the surface is evaporated, and the water that can be obtained from agricultural products is limited.
The geology of Miyako is three layers, and from the deepest layer, "Shimajiri mudstone layer", "Ryukyu limestone layer", "Shimajiri Merge". The rainwater permeated the easily accessible limestone layer, and then flowed to the sea along the lowermost Shimajiri Formation (inversely, this is a water-impermeable geology).
Therefore, the world's first underground dam system is adopted in which a wall is made in the red part of this figure and the water is stored in the limestone layer before the water flows into the sea.
At last, the first dam was completed in 2000. And Because sunlight does not hit the basement, it is also possible to prevent the water quality from deteriorating due to an increase in phytoplankton.
Today, thanks to this mechanism, not only sugar cane but also many agricultural industries such as pumpkin and mango have flourished.
The hall was large and there were various other display booths. Also displayed are the actual huge drilling machines used to make walls in the basement.
The area around the facility was farmland, and it was in a place that was a bit confusing. When you come close, turn this mark to the left.
|Facility Name||Underground Dam Museum, Miyakojima City|
|Address||Fukuzato1645-8, Gusukube Miyakojima CityMAP|
|Business hours||April-September 9:30am-6:15pm
|Closing day||Monday December 29 to January 3|
|Admission fee||300 yen|
|Parking Lot||There is enough space|
|notice||English is not supported maybe..|