Know More about Miyagase Dam
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Introducing Facilities Inside the Dam
Low-level spillway for normal use
External view of the low-level spillway for normal use
The low-level spillway for normal use is the lowest gate that is installed on Miyagase Dam at EL. 190m (Note 1: Intake port).
Situated at the end of a discharge pipeline that vertically passes through the dam body, this equipment is capable of discharging a maximum of 100m³ (Note 2) of water per second.(Note 1) EL: Elevation
(Note 2): Reference value: A 25m swimming pool at an elementary school has capacity of 375m³Used at Such Times
low-level spillway for normal use
When flooding occurs continuously, this facility conducts discharge to rapidly lower the water level before further flooding after it has been initially raised due to typhoon or heavy rainfall. Since priority is first given to using the high-level spillway for normal use, the low-level spillway for normal use can be regarded as a preliminary facility for conducting flood control (Note 3).
(Note 3) Flood control: One of Miyagase Dam's functions. This refers to the function of temporarily holding heavy rains caused by typhoon, etc. and conducting safe discharge to the downstream.
The Power to Stop Water: "High-pressure Radial Gate"
The gate is subject to the greatest water pressure in Japan!
Installed in deep water, the gate is almost entirely made from stainless steel and is arc-shaped to withstand high water pressure, and it is moved up and down by hydraulic power. The main gate has a design wet depth of 115.163m and is designed to withstand the highest water pressure of any high-pressure radial gate in Japan.