This facility controls the huge amount of water and huge water pressure stored in the dammed lake. In addition to flood control, which is the main purpose of the dam, there are numerous facilities for various types of water control. Examples include flow rate adjustment for constant river flow rate, selective water intake equipment for intake of water at an appropriate temperature, and measures against turbid water in the dammed lake.

Tokuyama dam emergency flood discharge (crest radial gate)

Main spillway in redevelopment project for Amagase Dam

• Main gate (radial gate)
  • 3.6 meters wide × 4.9 meters high × 9.0 meters radius
  • 2 gates
• Branch pipes
  • Inlet 10.3 meters in diameter (1 line)/outlet 3.6 meters wide × 5.0 meters high (2 lines)
• Total length
  • 43 meters

This gate controls river water, such as estuary weirs that maintain the water level at normal times and then allow river water to flow down quickly in the event of a flood, and gutters and floodgates that intake and discharge of water from the river. There are also various other facilities such as locks that allow ships to come and go upstream and downstream of the estuary weir, fishway gates that assist fish in swimming upstream, and retarding basin locks that store river water in the event of a flood.

• Nagashima water gate (horizontal roller gate)
  • 14.0 meter wide × 14.6 meters high (2 gates)

• Dotonbori river water gate
  • Left: Water control gate (2-stage roller gate)
    12.5 meters wide × 6.8 meters high (1 gate)
  • Right: Downstream lock (submerge radial gate)
    9.0 meters wide × 7.1 meter radius (1 gate)

A penstock transports water from a reservoir, etc., in a high location to a hydroelectric power plant in a low location. Since the water must drop all at once in order to generate power, the interior of the penstock is exposed to high pressure. Therefore, by connecting long distances along steep slopes, a penstock fulfills an important role for hydroelectric power generation.

• Ojiya power station, No. 3 penstock
  • Design water head of 74 meters
  • Extension of 78 meters
  • Inner diameter 3,350 to 4,500 millimeters

• The penstock of Higashiyokoyama hydropower station
  • Design water head of 119 meters
  • Extension of 62 meters × 4 pipes
  • Inner diameter of 1,200 to 1,500 millimeters

Dam renewal work is performed while the dam is operating at a high water level. Therefore, a temporary steel lid known as a "temporary closing facility" is installed on the upstream surface of the dam body to prevent the dammed lake water from flowing out to the downstream side when drilling holes in the dam body. Hitachi Zosen is experienced in constructing a large number of temporary closing facilities. Based on that know-how, we have developed a floating temporary closing method.

• Tsuruta dam upstream temporary closing facility
  • For additional spillway facilities: Inner area 11.0 meters wide × 4.0 meters deep × 38.0 meters high
  • For power generation and water intake: Inner area 13.0 meters wide × 3.7 meters deep × 30.5 meters high
  • Floating temporary closing: Inner area 11.0 meters wide × 4.0 meters deep × 25.5 meters high