Overview

Taki Dam, known locally as Taki Dam (滝ダム), is a gravity dam situated on the Tadami River in Fukushima Prefecture, Japan. The structure is located approximately 7.3 km east of the town of Tadami. As a key component of the region's hydroelectric infrastructure, the dam serves the primary purpose of hydroelectric power generation. It supports a dedicated power station with an installed capacity of 92 MW, which is operational and contributes to the energy output of the area. The facility is characterized by its robust gravity design, which relies on the weight of the structure to resist the upstream water pressure.

The dam's physical dimensions reflect its engineering scale. It stands 46 m tall and extends 264 m in length along the riverbed. These specifications allow the structure to create a substantial reservoir with a total capacity of 27,000,000 m³. Of this total volume, 10,300,000 m³ is designated as active storage specifically for power generation purposes. The remaining capacity serves as dead storage and buffer for seasonal variations in the Tadami River's flow.

The power station associated with the dam utilizes two Kaplan turbines, each rated at 46 MW, to convert the hydraulic energy into electricity. This configuration provides a balanced approach to energy production, allowing for flexibility in output based on water availability. The dam's spillway is equipped with four sluice gates, providing a controlled discharge capacity of 200 m³/s. This system is critical for managing water levels during peak flow periods and ensuring the structural integrity of the dam. Construction of the Taki Dam began in 1959, following surveys conducted in 1958, and was completed in 1961. The project represents a mid-20th-century effort to harness the hydroelectric potential of the Tadami River basin.

History and Construction

The development of the Taki Dam was executed with notable speed, reflecting the urgency of post-war infrastructure projects in Japan. Preliminary surveys for the structure were carried out in 1958. These initial assessments focused on the Tadami River, identifying the site as a viable location for gravity dam construction to support regional hydroelectric power generation. Following the survey phase, physical construction began in 1959. The project involved significant earthworks and concrete pouring to establish the dam's structural integrity along the riverbed.

Completion and Commissioning

Construction activities concluded rapidly, and the dam was complete in 1961. This two-year construction period allowed the facility to be commissioned during a critical phase of Japan's hydroelectric expansion. Upon completion, the dam immediately began supporting a 92 MW power station. The power generation infrastructure consists of 2 x 46 MW Kaplan turbines, designed to optimize water flow efficiency from the reservoir. The dam's structural dimensions were finalized as 46 m tall and 264 m long. These specifications were chosen to create a reservoir with a total capacity of 27,000,000 m3, of which 10,300,000 m3 is active for power generation. The rapid completion in 1961 ensured that the Taki Dam could contribute to the regional grid stability during the early 1960s. The spillway system, controlled by four sluice gates, was also finalized during this phase, providing a 200 m3/s discharge capacity to manage water levels effectively.

Engineering Design and Specifications

The Taki Dam is engineered as a gravity dam, a structural design that relies on the weight of the concrete or masonry to resist the horizontal force of the water. This structure is situated on the Tadami River in Fukushima Prefecture, Japan, and serves as the primary infrastructure for the local hydroelectric power generation system. The dam's dimensions are substantial, standing 46 m tall and spanning 264 m in length, providing the necessary mass and stability to manage the river's flow and create the required reservoir volume for power generation.

Structural Dimensions and Reservoir Capacity

The physical scale of the Taki Dam is defined by its height of 46 m and a crest length of 264 m. These dimensions contribute to the creation of a reservoir with a total capacity of 27,000,000 m3. Of this total volume, 10,300,000 m3 is designated as active storage, which is the portion of the reservoir volume that is directly utilized for hydroelectric power generation. The remaining volume serves as dead storage and other operational buffers. The dam's design ensures that the Tadami River's water is effectively harnessed to drive the power station's turbines.

Spillway and Discharge Mechanisms

Water management and flood control are handled by the dam's spillway system. The spillway is equipped with four sluice gates, which allow for precise control over the outflow from the reservoir. This configuration provides a total discharge capacity of 200 m3/s. The ability to regulate flow through these four gates is critical for maintaining reservoir levels during varying hydrological conditions and for managing peak flows to ensure the structural integrity of the dam and the efficiency of the downstream power generation.

Technical Specifications

Parameter Value
Dam Type Gravity dam
Height 46 m
Length 264 m
Reservoir Total Capacity 27,000,000 m3
Active Reservoir Capacity 10,300,000 m3
Spillway Type Four sluice gates
Discharge Capacity 200 m3/s

Hydroelectric Power Generation

The Taki Dam supports a dedicated hydroelectric power station with a total installed capacity of 92 MW, serving as the primary energy infrastructure associated with the gravity dam on the Tadami River. The power generation facility utilizes two Kaplan turbines, each contributing 46 MW to the total output, allowing for efficient energy production from the water flow of the Tadami River in Fukushima Prefecture, Japan. This configuration enables the plant to maintain operational status and provide a consistent power supply to the regional grid, leveraging the natural hydraulic head created by the dam's 46 m height.

Reservoir and Water Management

The reservoir created by the Taki Dam plays a critical role in the hydroelectric generation process, providing the necessary water storage to sustain turbine operation. The total storage capacity of the reservoir is 27,000,000 m3, which ensures a reliable water supply for power generation even during periods of variable river flow. Of this total volume, 10,300,000 m3 is designated as active storage, meaning this portion of the water is actively cycled through the turbines to generate electricity, optimizing the efficiency of the 92 MW power station.

Water management at the Taki Dam is facilitated by a spillway controlled by four sluice gates, which regulate the discharge capacity to maintain optimal reservoir levels and prevent overflow during high-flow periods. The spillway has a discharge capacity of 200 m3/s, allowing for precise control over the water volume entering the power station and the downstream sections of the Tadami River. This infrastructure ensures that the dam can effectively balance water storage for power generation with flood control and river flow management, supporting the long-term operational stability of the hydroelectric facility since its completion in 1961.

Reservoir Capacity and Water Management

The Taki Dam creates a reservoir with a total storage capacity of 27,000,000 m³ (21,889 acre⋅ft) on the Tadami River, according to Wikipedia. This volume represents the maximum physical storage potential of the impoundment, defined by the dam's structural dimensions and the surrounding topography of Fukushima Prefecture. The dam itself is 46 m (151 ft) tall and 264 m (866 ft) long, forming the gravity barrier that contains this water mass. The total capacity figure includes both the active storage used for daily power generation cycles and the dead storage or surplus capacity that provides flexibility during flood events or seasonal variations in the Tadami River flow.

Active Storage for Power Generation

Of the total 27,000,000 m³ reservoir volume, 10,300,000 m³ (8,350 acre⋅ft) is designated as active capacity for power generation, per Wikipedia. This active storage is the primary operational resource for the 92 MW hydroelectric power station. The power station utilizes two Kaplan turbines, each with a capacity of 46 MW, which draw from this active volume to drive electricity production. The ratio of active to total capacity indicates that approximately one-third of the reservoir's total volume is routinely cycled through the turbines to meet energy demand, while the remaining two-thirds serves as buffer storage. This configuration allows the plant to maintain consistent output even when inflow from the Tadami River fluctuates, leveraging the stored water to smooth out variations in river discharge.

Spillway and Discharge Management

Water management at the Taki Dam is further controlled by its spillway system, which is equipped with four sluice gates. The spillway has a discharge capacity of 200 m³/s (7,063 cu ft/s), according to Wikipedia. This infrastructure is critical for regulating the reservoir level, particularly during periods of high inflow or when the active storage reaches its limit. The sluice gates allow operators to release excess water downstream, preventing the reservoir from exceeding its safe operating levels and protecting the gravity dam structure from hydraulic pressure stress. The 200 m³/s discharge rate defines the maximum volume of water that can be released per second, ensuring that the Tadami River downstream can accommodate the outflow without excessive flooding, while also allowing for strategic water release to optimize the active storage for the Kaplan turbines. The coordination between the 10,300,000 m³ active storage and the 200 m³/s spillway capacity enables efficient water management, balancing the need for consistent hydroelectric power generation with the physical constraints of the dam and the natural flow dynamics of the Tadami River. The dam was completed in 1961, following surveys in 1958 and construction starting in 1959, establishing the baseline infrastructure for this water management system.

Location and Regional Context

The Taki Dam is situated on the Tadami River, positioned 7.3 km east of the town of Tadami within Fukushima Prefecture, Japan. This location places the facility in the mountainous terrain of the region, where the river's flow is harnessed for hydroelectric power generation. The dam's geographic setting is integral to its function as a gravity dam, utilizing the natural topography to create a reservoir with a total capacity of 27,000,000 m3. Of this total volume, 10,300,000 m3 is designated as active storage for power generation, highlighting the strategic use of the river's watershed to support the 92 MW power station. The Taki Dam is part of a broader system of dams along the Tadami River, which plays a significant role in the regional energy infrastructure. Specifically, the Taki Dam is located downstream from the Tadami Dam and upstream from the Honna Dam. This arrangement allows for coordinated water management and power generation across the river's course. The positioning relative to these other dams influences the flow dynamics and reservoir levels, ensuring efficient operation of the Kaplan turbines that drive the power station. The proximity to Tadami town also facilitates access for maintenance and operational oversight, while the surrounding landscape provides the necessary elevation and water volume to sustain the dam's 46 m height and 264 m length. The regional context of the Taki Dam includes the natural environment of Fukushima Prefecture, where the Tadami River serves as a key water resource. The dam's construction, which began in 1959 and was completed in 1961, was informed by surveys conducted in 1958, reflecting a careful assessment of the river's characteristics and the surrounding geography. The dam's spillway, equipped with four sluice gates, has a discharge capacity of 200 m3/s, which helps manage water levels and mitigate potential flooding in the downstream areas, including the vicinity of Tadami town. This infrastructure supports not only energy production but also the broader hydrological balance of the Tadami River system, integrating with the Honna and Tadami Dams to optimize the use of water resources in the region.

Why it matters

The Taki Dam serves as a critical node in the energy infrastructure of Fukushima Prefecture, functioning as a key component of the broader Tadami River hydroelectric scheme. Located on the Tadami River, the facility provides consistent power generation capabilities essential for regional grid stability. The plant's operational significance is derived from its strategic design, which integrates a substantial reservoir capacity with efficient turbine technology to maximize energy output from the water source.

Hydroelectric Generation Capacity

The power station associated with Taki Dam has an installed capacity of 92 MW, achieved through two 46 MW Kaplan turbines. This configuration allows for flexible power generation, as Kaplan turbines are particularly effective at maintaining efficiency across varying flow rates, a common characteristic of river-based hydro schemes. The dam's completion in 1961 marked the introduction of a reliable baseload power source for the region, contributing to the energy mix of Fukushima Prefecture for decades. The facility remains operational, continuing to deliver electricity generated from the kinetic energy of the Tadami River.

Water Management and Reservoir Function

Beyond electricity production, the Taki Dam plays a vital role in water management within the Tadami River basin. The structure creates a reservoir with a total capacity of 27,000,000 m³, of which 10,300,000 m³ is designated as active storage for power generation. This active volume ensures a consistent water supply to the turbines, smoothing out seasonal fluctuations in river flow. The dam's spillway, equipped with four sluice gates, provides a discharge capacity of 200 m³/s, offering critical flood control benefits for downstream communities. The gravity dam structure, standing 46 m tall and extending 264 m in length, provides the necessary structural integrity to manage these water volumes effectively. The strategic location, situated 7.3 km east of Tadami, allows the dam to capture and regulate water flow from the upper reaches of the river, optimizing both energy production and hydraulic control for the surrounding area.

What distinguishes Taki Dam from other gravity dams?

The design of Taki Dam reflects a specific engineering response to the hydrological profile of the Tadami River, distinguishing it through its integration of Kaplan turbines and a precise spillway configuration. As a gravity dam, the structure relies on its mass to resist the water pressure, standing 46 m tall and spanning 264 m in length. This physical footprint supports a reservoir capacity of 27,000,000 m³, a volume specifically managed to optimize hydroelectric output rather than mere storage.

Turbine Selection and Flow Optimization

The power station associated with the dam utilizes two Kaplan turbines, each rated at 46 MW, for a combined installed capacity of 92 MW. The choice of Kaplan turbines is critical to the dam’s operational efficiency. Unlike fixed-blade turbines, Kaplan units feature adjustable blades that allow for high efficiency across a variable range of flow rates. This adaptability is particularly advantageous for the Tadami River, where seasonal variations in water volume can significantly impact head pressure. By adjusting the blade angle, the turbines maintain optimal performance whether the river is in peak flow or experiencing lower discharge periods, ensuring consistent energy generation from the 10,300,000 m³ of active reservoir capacity.

Spillway Configuration

This configuration allows for precise control over water release, balancing the need to maintain reservoir levels for power generation with the necessity of managing flood risks downstream. The use of multiple sluice gates, rather than a single overflow crest, offers greater flexibility in regulating the outflow, which is essential for maintaining the hydraulic head required by the Kaplan turbines. This design ensures that the dam can effectively handle the Tadami River’s flow characteristics while minimizing water loss during periods of high inflow.

See also