Overview
The Tsubawara Dam, alternatively identified in records as the Tsubakihara Dam, is a significant hydroelectric infrastructure project located in Gifu Prefecture, Japan. This facility functions as a gravity dam situated on the Shō River, positioned approximately 5 km (3.1 mi) north of the town of Shirakawa. As part of the broader Shō River basin development, the dam holds a specific geographical rank among the nine dams constructed along this waterway, standing as the seventh furthest downstream. The structure serves as the primary water retention and flow regulation mechanism for the associated hydroelectric power station, which is operated by the Kansai Electric Power Company.
The construction of the Tsubawara Dam took place between 1952 and 1953, marking a key phase in the regional energy infrastructure development of the mid-20th century. The associated hydroelectric power station, which utilizes the water resources managed by the dam, has a total installed capacity of 107 MW. The development of the power generation component was executed in two distinct phases. The first part of the power station was commissioned in 1954, shortly after the dam's structural completion, while the second part was commissioned later in 1975. This phased approach allowed for the gradual integration of the facility into the regional grid managed by the Kansai Electric Power Company. The dam remains operational, continuing to contribute to the energy output of the region through its gravity-based design and strategic location on the Shō River.
Hydroelectric Infrastructure and Capacity
The Tsubawara Dam supports a 107 MW hydroelectric power station operated by Kansai Electric Power Company. The facility is part of the broader hydroelectric infrastructure along the Shō River in Gifu Prefecture, Japan. The power station was developed in two distinct phases to maximize energy generation capacity over time. The first part of the power station was commissioned in 1954, marking the initial operational milestone for the facility. The second part of the power station was commissioned in 1975, completing the expansion of the hydroelectric infrastructure. This two-part commissioning process allowed for a gradual increase in power output, with the first phase contributing 42 MW and the second phase adding 65 MW to the total installed capacity. The combined capacity of 107 MW represents the full operational potential of the Tsubawara hydroelectric power station.
Technical Specifications and Dam Structure
The Tsubawara Dam is a gravity dam constructed between 1952 and 1953. Gravity dams rely on their own weight to resist the horizontal force of the water, providing stability and structural integrity for the reservoir. The dam is located on the Shō River, approximately 5 km north of Shirakawa in Gifu Prefecture. It is the seventh dam furthest downstream among the nine dams situated on the Shō River. The hydroelectric power station utilizes the water stored and regulated by the gravity dam to generate electricity. The facility remains operational, continuing to contribute to the regional energy supply in Japan. The integration of the dam and power station represents a key component of the Shō River's hydroelectric development strategy. The two-phase construction approach allowed for efficient use of resources and progressive integration into the Kansai Electric Power Company's grid infrastructure.
Construction History
The Tsubawara Dam, alternatively referred to as the Tsubakihara Dam, is a gravity-type structure situated on the Shō River in Gifu Prefecture, Japan. The construction of the dam itself was a focused engineering effort carried out over a two-year period, commencing in 1952 and concluding in 1953. This rapid construction timeline reflects the post-war infrastructure development pace in the region, establishing the primary water retention capacity needed for the hydroelectric scheme. The dam is located approximately 5 km north of Shirakawa and holds the position of the seventh dam furthest downstream among the nine dams that characterize the Shō River system.
Power Station Development Phases
While the civil works for the gravity dam were completed by 1953, the associated hydroelectric power station, with a total installed capacity of 107 MW, was developed in two distinct operational phases. This early commissioning allowed Kansai Electric Power Company to begin harnessing the hydraulic head provided by the newly constructed dam. The power station's development did not conclude immediately after the initial launch; rather, it underwent a second phase of expansion and integration.
This two-part commissioning strategy suggests a phased approach to maximizing the energy output from the Shō River's flow, potentially allowing for technological upgrades or capacity adjustments between the 1954 launch and the 1975 completion. The operator, Kansai Electric Power Company, has maintained the facility in operational status since the final phase was integrated. The staggered commissioning dates—1954 for the first part and 1975 for the second—highlight the long-term engineering strategy employed to optimize the 107 MW output of the Tsubawara hydroelectric power plant.
What is the role of the Tsubawara Dam in the Shō River system?
The Tsubawara Dam serves as a critical node within the broader hydroelectric infrastructure of the Shō River basin in Gifu Prefecture, Japan. As part of a sequence of nine dams constructed along the river’s course, the Tsubawara Dam holds the specific position of being the seventh furthest downstream. This placement is not arbitrary; it reflects a strategic engineering decision to harness the river’s gradient and flow volume at a point that optimizes energy generation while coordinating with upstream storage and downstream release patterns. The Shō River system is characterized by a cascade of hydroelectric facilities, each contributing to the regional power grid managed primarily by the Kansai Electric Power Company. The Tsubawara Dam’s role is therefore both independent and interdependent: it generates power through its own 107 MW capacity while also influencing the hydraulic conditions for the two dams located further downstream and receiving regulated flow from the six dams upstream.
Position within the Cascade System
Being the seventh of nine dams implies that the Tsubawara Dam operates in the lower-middle section of the Shō River’s hydroelectric chain. Upstream, six other dams regulate the water volume, sediment load, and seasonal flow variations before the water reaches the Tsubawara gravity dam. This upstream regulation helps stabilize the inflow to the Tsubawara reservoir, allowing for more consistent turbine operation compared to a standalone dam on an unregulated river. The gravity dam structure, constructed between 1952 and 1953, was designed to withstand the hydrostatic pressure of the accumulated water from these upstream sources, ensuring structural integrity and efficient power generation. The dam’s location, approximately 5 km north of Shirakawa in Gifu Prefecture, places it in a geographic zone where the river’s topography supports significant head height, a key factor in hydroelectric efficiency.
Relationship with Downstream Infrastructure
Downstream of the Tsubawara Dam, two additional dams continue the energy extraction process along the Shō River. The water released from the Tsubawara power station flows into the next reservoir in the sequence, meaning that the operational scheduling of the Tsubawara turbines directly affects the inflow rates and storage levels of these downstream facilities. This creates a coordinated operational dynamic where the Kansai Electric Power Company must balance the power output of the Tsubawara station with the needs of the downstream dams. For instance, during peak demand periods, the Tsubawara Dam may increase its discharge to boost immediate power generation, which in turn increases the inflow to the downstream reservoirs, potentially allowing them to generate additional power or store water for later use. This interdependence highlights the Tsubawara Dam’s role as a mid-cascade regulator, bridging the upper and lower sections of the Shō River’s hydroelectric network.
Historical Development and Operational Phasing
The Tsubawara Dam’s integration into the Shō River system was achieved through a phased development approach. The first part of the associated 107 MW hydroelectric power station was commissioned in 1954, marking the initial operational phase of the dam. However, the full capacity was not realized until the second part of the power station was commissioned in 1975. This 21-year gap between the two commissioning dates suggests a strategic expansion of the hydroelectric infrastructure, likely driven by increasing regional energy demand and advancements in turbine technology. The phased construction allowed the Kansai Electric Power Company to test the dam’s performance and integrate it into the broader grid before fully utilizing its capacity. This historical development underscores the Tsubawara Dam’s evolving role within the Shō River system, transitioning from a partial contributor to a fully integrated component of the regional power supply.
Geographic Context and Location
The Tsubawara Dam is situated in Gifu Prefecture, Japan, positioned along the course of the Shō River. The structure is located approximately 5 km north of the town of Shirakawa, placing it within a defined segment of the river’s downstream progression. Within the broader hydrological system of the Shō River, which features a total of nine dams, the Tsubawara Dam ranks as the seventh furthest downstream. This specific positioning is critical to its operational role within the river’s hydroelectric cascade, influencing water flow dynamics and storage capacity relative to upstream and downstream infrastructure. The dam is also known by the alternative name Tsubakihara Dam, a designation that appears in regional and technical documentation.
Regional Setting
Gifu Prefecture, located in the Chūbu region of Honshu, provides the geographical context for the Tsubawara Dam’s operation. The Shō River flows through this prefecture, serving as a key water resource for energy generation and local hydrology. The dam’s gravity structure is integrated into the river’s natural topography, leveraging the elevation and flow characteristics of the Shō River to support its 107 MW hydroelectric power station. The proximity to Shirakawa, a town in Gifu Prefecture, underscores the dam’s regional significance, connecting energy infrastructure with local municipal geography. The construction of the dam between 1952 and 1953 reflects mid-20th-century engineering efforts to harness the Shō River’s potential, with the power station’s commissioning in two phases—1954 and 1975—further adapting the facility to evolving energy demands. The dam’s location and design remain consistent with its role as a gravity dam, a type that relies on its weight to resist water pressure, ensuring stability within the Shō River’s flow regime.
Why it matters
The Tsubawara Dam serves as a critical node within the hydroelectric infrastructure of the Shō River, contributing significantly to the regional energy security of Japan. As the seventh dam in a sequence of nine structures along the river’s course, it exemplifies the strategic use of cascading hydroelectric development to maximize water resource utilization. This configuration allows for a more consistent and regulated flow of water downstream, enhancing the overall efficiency of the river’s hydroelectric potential. The dam’s gravity design, constructed between 1952 and 1953, provides robust structural integrity, essential for managing the variable flow of the Shō River and ensuring reliable power generation over decades of operation.
Integration into the Kansai Grid
Operated by the Kansai Electric Power Company, the Tsubawara Dam plays a vital role in stabilizing the electrical grid in western Japan. With an installed capacity of 107 MW, the associated power station provides a substantial baseline of renewable energy, crucial for balancing the load on the Kansai grid. The power station was developed in two distinct phases, with the initial commissioning in 1954 and the second part added in 1975. This phased approach allowed for gradual integration into the growing energy demands of the region, demonstrating the adaptability of hydroelectric infrastructure to evolving market needs. The dam’s contribution is particularly valuable during peak demand periods, where the flexibility of hydroelectric power allows for quick adjustments in output, thereby enhancing grid stability.
Strategic Location and Regional Impact
Located approximately 5 km north of Shirakawa in Gifu Prefecture, the Tsubawara Dam’s position is strategically significant for both energy distribution and regional development. Its proximity to Shirakawa facilitates efficient transmission of generated power to nearby urban centers and industrial zones, reducing transmission losses and enhancing the economic viability of the project. The dam also contributes to flood control and water supply management, providing multifaceted benefits to the local community. The integration of the Tsubawara Dam into the broader Shō River cascade underscores the importance of coordinated water resource management in maximizing the hydroelectric output and ensuring sustainable energy production in the region.