Aso-Kuju National Park
Waters of Aso and Kuju
The location of the Aso grasslands, at a high altitude and close to the sea, means they receive a significant amount of rainfall annually; more than double the national average for the rest of Japan. When it rains, grass covering the broad grassland areas moderates the flow of water so that it seeps more slowly into the mineral-rich volcanic ground. It then collects in natural underground reserves and feeds streams and rivers that irrigate northern Kyushu. They include six Class A rivers that provide water for living and agriculture to over five million people in the region. The area is commonly regarded as the water reservoir of Kyushu.
In certain areas, groundwater wells up to the surface under cliffs and at the base of hills, where it forms natural springs producing fresh, clean water. Over large areas of low-lying land, water collects to form a number of wetlands that support a wide range of unique plant and animal life. This has contributed to the area being awarded UNESCO Global Geopark status. There are many hot spring (onsen) towns in the Aso area. Hot springs have been an important part of the daily lives of the locals since ancient times. Many tourists visit the area to bathe in the volcanic hot spring waters, bringing significant economic benefits to the area.