Dam type

Gravity Concrete Dam

Most of the dams found throughout Japan are of this type because it is versatile and can be constructed in rivers and valleys of any shape. Since the weight of the dam itself can support the water pressure on the entire embankment, the bedrock on both sides must be strong.

Arch-type concrete dam

The embankment is constructed on an arch to distribute the water pressure on the entire embankment to the bedrock on both sides. Therefore, the embankment can be constructed thinly. The foundation bedrock is cut into a V-shaped valley to absorb the distributed water pressure.

Hollow gravity dam

The basic structure is the same as that of a gravity concrete dam, but by making the inside of the embankment hollow, materials can be saved and construction costs can be reduced.

Buttress Dam

Also known as a "support wall dam," it is a dam with a concrete wall support system. There are only six such dams in Japan, and the Mitaki Dam is the last buttress dam in Japan.

Earth-fill dam

Also known as "earth damAlso abbreviated as "dam". A dam is made by layering soil as the material. Because it is relatively easy to construct, it is not suitable for large-scale dams, but for small-scale dams such as those built in reservoirs.

Central barrier-type rockfill dam

A rock-fill dam is a dam made of rock, not soil as in an earth-fill dam. First, a clay wall is built in the center of the embankment (core) to prevent water from seeping in, then a filter layer is built around the core, and rocks are arranged on the surface of the embankment to create a three-layered structure that makes the embankment strong.

Surface impervious rockfill dam

A dam with the surface of the embankment on the lake side covered with asphalt or concrete to prevent water from seeping into the embankment.