Miyagase Dam in Kanagawa Prefecture is the biggest dam in Japan's capital region. It's close enough to Tokyo and Yokohama to visit on a day trip, and it has become a popular tourist spot. On fixed days between April and November there are even "sightseeing discharges," a rare occurrence in Japan. Over the course of six minutes, a huge quantity of water is released over a drop of 70 meters, and visitors can view the power of the water flowing out and the mist floating up from an observation area below the dam. On sunny days, the mist and water often results in rainbows. After taking an elevator to the top of the dam, the entire dam and the nature of Miyagase will be visible, and if the weather is good, as far as Yokohama can be seen.
There are plenty of other activities as well, including the road train Aichan-go that runs within the premises of the dam, the cable car Ink Line that connects the top and bottom of the embankment, the Miya Maru dam lake cruise boats, dam and water resources, and the Water and Energy Hall where visitors can have fun while learning about energy. With so many activities, visitors will have no problem spending a entire day here.
Additionally, the dam is illuminated at night for the Miyagase Dam Night Discharge, during the Christmas season illumination events take place on the shores of Miyagaseko Lake, and there are plenty of fireworks and other events throughout the year, so make sure to check the official website for detailed event information.
Sightseeing discharges: every Wednesday, the second Sunday of each month, the second and fourth Fridays of each month, and other irregular days (events, etc.) from April through November.
*There are no sightseeing discharges December through March.
Times: 11:00 a.m. to 11:06 a.m. (six minutes long) and 2:00 p.m. to 2:06 p.m. (six minutes long).