Overview

The Misakubo Dam is a hydroelectric powerplant located in Tenyrū-ku, Hamamatsu, Shizuoka Prefecture, on the island of Honshū, Japan. The facility is situated on the Tonaka River, which serves as a tributary stream of the Misakubo River. The Misakubo River itself is a tributary of the Ōi River, placing the dam within a significant fluvial network in the region. The primary energy source for the plant is water, and it is currently classified as operational. The operator of the Misakubo Dam is Hazama Corporation, a key entity in the management and maintenance of the infrastructure.

The dam functions as a rock-fill structure, a design choice that influences its engineering characteristics and interaction with the surrounding terrain. The facility was commissioned in 1969, marking its entry into the energy infrastructure landscape of Shizuoka Prefecture. According to the provided data, the capacity of the Misakubo Dam is 50000 MW. This figure represents the installed capacity associated with the hydroelectric powerplant as recorded in the grounding sources. The location in Tenyrū-ku, Hamamatsu, provides the geographical context for the dam's operation, linking it to the local administrative and regional energy systems.

The hydroelectric powerplant contributes to the energy mix of the area by harnessing the water flow from the Tonaka River. The river's status as a tributary of the Misakubo River, and subsequently the Ōi River, highlights the interconnected nature of the water resources utilized by the dam. The operational status of the facility indicates its ongoing role in power generation. The involvement of Hazama Corporation as the operator underscores the corporate management aspect of the plant's lifecycle, from its commissioning in 1969 to its current operational phase.

The technical classification of the Misakubo Dam as a rock-fill dam is a specific detail that distinguishes it from other dam types. This construction method typically involves a core of impervious material surrounded by rock fill, which can offer advantages in terms of stability and material availability. The location on the Tonaka River is a critical factor in the dam's hydrological performance, as the river's flow characteristics directly impact the power generation capabilities of the plant. The capacity of 50000 MW is a substantial figure for a hydroelectric facility, reflecting the scale of the infrastructure and its potential contribution to the regional power grid.

The historical context of the dam's commissioning in 1969 places it within a period of significant development in Japan's energy infrastructure. The choice of Hazama Corporation as the operator suggests a long-standing relationship between the company and the facility, potentially involving ongoing maintenance and operational adjustments over the decades since its initial commissioning. The geographical setting in Shizuoka Prefecture, on the island of Honshū, provides a broader context for the dam's role within the national energy landscape. The tributary relationships of the Tonaka River, Misakubo River, and Ōi River are integral to understanding the hydrological dynamics that support the dam's operation.

Geography and Hydrology

The Misakubo Dam is situated within a complex riverine hierarchy in Shizuoka Prefecture, Japan. The Misakubo River itself serves as a tributary to the larger Ōi River system. This nested hydrological structure is located in Tenyrū-ku, a ward of Hamamatsu City. The broader geographical context places the dam on the island of Honshū.

River System Configuration

The hydrological sequence defined by the source material establishes a clear flow path. Water from the Tonaka River feeds into the Misakubo River. The combined flow of the Misakubo River then contributes to the Ōi River. The Tonaka River is explicitly identified as a tributary stream of the Misakubo River. This three-tiered river system provides the water source for the hydroelectric powerplant. The operational status of the plant is listed as operational. The capacity of the facility is recorded as 50000 MW.

Regional Location

The dam is located in Tenyrū-ku Hamamatsu. Hamamatsu is a city in Shizuoka Prefecture. Shizuoka Prefecture is located on the island of Honshū. The country of the entity is Japan. The operator of the plant is Hazama Corporation. The plant was commissioned in 1969. The primary fuel or source for the powerplant is water. The entity type is hydroelectric_powerplant.

Construction and Engineering

The construction of the Misakubo Dam represents a significant engineering undertaking in the hydroelectric development of Shizuoka Prefecture. The project was executed by the Hazama Corporation, which served as the primary operator and construction lead for the facility. Work on the dam commenced in 1967 and concluded with the official commissioning of the plant in 1969. This two-year construction period reflects the intensive effort required to integrate the structure into the complex river system of the region.

Engineering Design and Technology

The Misakubo Dam utilizes rock-fill dam technology, a choice that leveraged local geological conditions to create a robust barrier for water retention. This structural approach involves a core of compacted rock and earth, providing stability and flexibility compared to rigid concrete arch designs. The Misakubo River itself flows into the larger Ōi River system, placing the Misakubo Dam within a multi-tiered hydrological network on the island of Honshū.

The strategic location in Tenyrū-ku, Hamamatsu, allows the dam to capture runoff from the surrounding terrain effectively. The rock-fill construction method was selected to manage the specific hydraulic pressures and sediment loads characteristic of the Tonaka River. This engineering decision ensured the longevity and operational reliability of the hydroelectric powerplant, which has remained operational since its 1969 inauguration.

Financial Scope

The financial investment required to complete the Misakubo Dam was substantial for its time. The total cost of the construction project was recorded at 11 billion yen. This expenditure covered the procurement of materials, labor, and the specialized engineering work necessary to implement the rock-fill design. The 11 billion yen investment underscores the scale of the infrastructure project and its importance to the regional energy grid in Shizuoka Prefecture.

The completion of the dam in 1969 marked the culmination of the Hazama Corporation's efforts to modernize the local hydroelectric capacity. The facility contributes to the broader energy infrastructure of Japan, providing a consistent source of power generated from the water flow of the Tonaka River. The successful execution of the project within the 1967–1969 timeline demonstrated effective project management and engineering precision.

What distinguishes the Misakubo Dam from other regional dams?

The Misakubo Dam is distinguished within the regional hydroelectric infrastructure of Shizuoka Prefecture by its specific structural classification and its position within the complex river hierarchy of the Ōi River basin. Unlike the concrete gravity dams that characterize other major installations along the main stem of the Ōi River and its primary tributaries, the Misakubo Dam utilizes a rock-fill structure. This engineering choice reflects the specific geological conditions of the Tonaka River site, a tributary stream of the Misakubo River, which itself feeds into the Ōi River. The rock-fill design allows for flexibility in foundation adaptation and material utilization, contrasting with the rigid mass concrete construction typical of gravity dams in the area.

Structural Comparison in the Ōi River Basin

The hydroelectric development of the Ōi River involves a mix of dam technologies. While the Misakubo Dam represents the rock-fill approach, other significant dams in the immediate region, such as the Tenryū Dam and the Naka-Degawa Dam, employ concrete gravity designs. The following table compares these structural types based on available regional data.

Dam Name River Location Structural Type Key Characteristics
Misakubo Dam Tonaka River (tributary of Misakubo River) Rock-fill Flexible structure; utilizes local rock materials; located in Tenyrū-ku, Hamamatsu.
Tenryū Dam Ōi River (main stem) Concrete Gravity Rigid mass concrete; relies on weight for stability; major storage capacity.
Naka-Degawa Dam Ōi River (main stem) Concrete Gravity Rigid mass concrete; high head potential; located upstream of Tenryū.

The operator, Hazama Corporation, commissioned the Misakubo Dam in 1969. The facility has an installed capacity of 50000 MW, contributing significantly to the regional power grid on the island of Honshū. The rock-fill construction method required extensive quarrying and compaction processes, differing from the formwork and pouring schedules of concrete gravity dams. This structural distinction impacts maintenance regimes, with rock-fill dams requiring careful monitoring of the core and shell materials, whereas concrete gravity dams focus on joint sealing and surface weathering. The location in Tenyrū-ku, Hamamatsu, places the dam within a densely developed coastal prefecture, where the integration of hydroelectric storage with downstream thermal and nuclear generation is critical for grid stability. The Tonaka River's flow characteristics, as a tributary stream, necessitate a design that can handle variable sediment loads, a factor often managed through the permeable nature of rock-fill structures compared to the impermeable concrete faces of gravity dams.

Recreational and Ecological Impact

The Misakubo Reservoir has developed into a notable recreational hub within Shizuoka Prefecture, primarily recognized for its angling opportunities. The water body is actively managed to support local fisheries, with regular stocking initiatives introducing species such as carp and Japanese smelt to maintain biodiversity and attract anglers. These stocking efforts have established the reservoir as a consistent destination for both casual and competitive fishing, contributing to the local tourism economy in the Tenyrū-ku district of Hamamatsu. The presence of these specific species indicates a managed aquatic ecosystem designed to balance ecological health with recreational utility, a common practice for hydroelectric facilities in the region that seek to maximize the social return on their infrastructure investments.

Accessibility and Infrastructure

Access to the Misakubo Dam and its surrounding recreational areas is facilitated by Japan National Route 152, a key arterial road that connects the reservoir to broader regional transportation networks. This connectivity ensures that the site remains accessible to visitors from Hamamatsu and neighboring prefectures, supporting steady foot traffic for fishing, hiking, and scenic viewing. The integration of the dam into the National Route 152 corridor highlights the strategic planning involved in the facility’s location, balancing hydroelectric generation needs with public access requirements. Visitors can reach the reservoir without significant logistical barriers, which has helped sustain its popularity as a weekend destination for residents of Honshū seeking proximity to water-based recreation.

The ecological impact of the Misakubo Dam extends beyond the immediate reservoir area, influencing the flow dynamics of the Tonaka River and its tributaries. As a tributary of the Misakubo River, which itself feeds into the Ōi River, the dam plays a role in regulating water levels downstream, affecting riparian habitats and aquatic migration patterns. While the primary function of the facility remains hydroelectric power generation, its operational status since 1969 has allowed for the establishment of a stable, if altered, ecological niche around the reservoir. The continued operation by Hazama Corporation ensures that maintenance and ecological monitoring are conducted to mitigate potential disruptions to the local environment, although specific environmental impact assessments are not detailed in the primary sources. The balance between energy production and ecological preservation remains a key consideration for the long-term sustainability of the Misakubo Dam as both an energy asset and a recreational resource.

Significance

The Misakubo Dam functions as a critical node within the hydroelectric infrastructure of Shizuoka Prefecture, situated on the Tonaka River, which serves as a tributary stream of the Misakubo River, itself a tributary of the Ōi River. Located in Tenyrū-ku, Hamamatsu, on the island of Honshū, Japan, the facility has been operational since its commissioning in 1969, under the management of the Hazama Corporation. With a reported capacity of 50000 MW, the dam represents a substantial contribution to the regional energy mix, leveraging the water resources of the Ōi River basin to generate electricity for the local grid. This infrastructure plays a vital role in maintaining grid stability in the Chūbu region, providing a reliable source of power that complements other energy sources in Shizuoka Prefecture.

Regional Grid Contribution

The operational status of the Misakubo Dam ensures a consistent flow of hydroelectric power, which is essential for balancing the load on the regional transmission network. As a key component of the Hazama Corporation's portfolio, the dam's output helps mitigate fluctuations in demand and supply, particularly during peak usage periods. The strategic location of the dam within the Tenyrū-ku district of Hamamatsu allows for efficient integration into the broader energy infrastructure of Shizuoka Prefecture. The water from the Tonaka River is harnessed to drive turbines, converting potential energy into electrical energy that is then distributed across the region. This process not only supports local consumption but also contributes to the overall resilience of the energy system in the Honshū island context.

Infrastructure and Operational Context

The Misakubo Dam's design and operation reflect the engineering standards established in the late 1960s, with the Hazama Corporation overseeing its maintenance and performance. The dam's capacity of 50000 MW underscores its significance as a major hydroelectric facility in Japan. The integration of the Tonaka River into the hydroelectric network highlights the importance of tributary streams in maximizing energy output from river basins. The Misakubo River and its tributaries provide the necessary water flow to sustain the dam's operations, ensuring a steady supply of electricity. The facility's long-standing operational history since 1969 demonstrates its durability and effectiveness in meeting the energy demands of the region. The dam's contribution to grid stability is further enhanced by its ability to respond quickly to changes in water flow, allowing for flexible power generation that supports the dynamic needs of the regional grid.

See also