What is a weir?

A weir is also called as 'low-head dam'; it is a facility to store flowing waters. Historic record indicates our ancestors built weirs for many purposes. They stored water using weirs for agricultural purpose and released water to downward rice paddies when the water level reaches to the highest. The weirs built in the four rivers are basically the same in its logic. We enlarge the water vessel by digging out the riverbed deeper to store more water. However, different from old static types in a structural viewpoint, our movable weirs which are built in the four rivers basins can freely operate the sluice gate to control the flow so to be effective for flood and drought. The 16 movable weirs are all managed undercutting-edge IT system with its own hydroelectric power. By this system, dams of upper stream and level of estuary can be organically controlled.