Shin Jinma

Planned high water flow rate indicates the river flow rate when flood control is carried out by a dam after the dam is constructed, compared to the base high water flow rate. In other words, the planned high water flow rate is the flow rate obtained by subtracting the amount of flood control by flood control facilities such as dams from the base high water flow rate. The water level at which the planned high water flow rate is displayed as a river channel cross section is called the planned high water level.

The planned sediment capacity is the amount of sediment that is assumed to flow into a dam lake over a 100-year period. In Japan, where there are many mountains, more sediment than planned may flow into dam lakes due to the influence of the Median Tectonic Line and crustal movement such as earthquakes. The sediment problem is particularly serious in the Tenryu River system.

A catwalk is a narrow passageway installed downstream of the embankment wall, mainly in concrete dams, for work during the construction phase of the dam and for inspection after completion. They are especially seen in arch dams. As with the audit corridor, the general public is not allowed to enter the corridor, but it may be opened only for various events or when special permission is granted.

A cable crane is a crane used in dam construction to transport materials and place concrete. Since they transport materials from the aggregate plant to the dam embankment, cables are usually stretched across the dam. Cable cranes themselves are not unique to dams, but those associated with dam construction are generally large, and sometimes only the crane foundations remain after the dam is completed.

Reverse control reservoirs exist at large hydroelectric power plants where the flow increases during the day and decreases at night. A "reverse control reservoir" is a dam that is also built downstream of a power plant to store water, and by releasing a certain amount of water, the flow downstream is regulated. Depending on the size of the dam, there are dams and weirs that serve as reverse control reservoirs.

The base high water flow rate refers to the river flow rate (1/100 chance flow rate) at the time of a flood that is expected to occur once every 100 years (or once every 200 years) under the river conditions prior to dam construction. The term "Takamizu" is used to avoid mistakenly reading "Kozui" as "high water. The maximum value of this flow is the basis for flood control planning. When graphing, a graph called a "hydrograph" is created with time on the horizontal axis and flow rate on the vertical axis.

The foundation ground is the ground that supports the weight of the dam. In some dams, the foundation ground is quite deep. The embankment height, which expresses the height of the dam, is the height measured from the foundation ground to the top of the embankment. Therefore, some dams may actually appear lower than the embankment height.

An audit corridor is a passageway used to check for damage inside the dam embankment. Normally, it is off-limits to all but authorized personnel. If permission is obtained, visitors may be allowed to take a special tour. However, if the dam is designated as a "dam open to the community," it may be used as a tour course, but in most cases it is a separate passage from the original audit corridor.

A temporary drainage tunnel is a kind of detour tunnel that is dug from upstream to downstream of a dam site during dam construction to divert overflowing upstream water downstream by damming the river. One of the temporary drainage channels. It is constructed to prevent overflow, to prevent the downstream river from becoming a waterless river, and to keep the construction site dry.

The River Law is a current administrative law enacted in 1964 for the purpose of preventing floods and other disasters in Japan, maintaining normal functions, maintenance, conservation, and proper use of rivers. The Act defines and classifies rivers, and defines management facilities related to rivers.