Manno Reservoir

At around 20 kilometers in circumference, Manno Reservoir in Mannou Town, Kagawa, is one of the largest irrigation reservoirs in Japan. It is said that a reservoir was first constructed here in the early eighth century. Influential Buddhist priest and scholar Kobo Daishi (Kukai; 774–835) then oversaw upgrades to strengthen the reservoir in 821, using the latest civil engineering technology from the Tang Dynasty to construct the first arched dam in Japan. Over time, the reservoir has been continually renovated and improved, and now has a storage capacity of some 15.4 million tons of water.