Overview

The Yele Dam is an operational hydroelectric powerplant located in Sichuan Province, China. This infrastructure project is situated on the Nanya River, specifically along the administrative border between Mianning County and Shimian County. The facility functions primarily as an embankment dam designed to harness water resources for electricity generation. It supports a power station with an installed capacity of 240 MW, contributing to the regional energy grid in southwestern China. The dam’s structural design is tailored to the specific geological and hydrological conditions of the Nanya River basin, ensuring stability and efficient water diversion for power production.

Structural Characteristics and Seismic Design

The Yele Dam exhibits significant engineering specifications, measuring 124.5 metres in height and 411 metres in length. A critical aspect of its construction is its location within a Level VIII earthquake intensity zone, which necessitated specialized material choices for its core. The core of the dam is composed of asphalt concrete, a material selected for its flexibility and durability under seismic stress. This design choice reflects the engineering response to the regional geological activity, ensuring the embankment can withstand substantial ground movement. The use of asphalt concrete in the core is a notable technical feature that distinguishes this dam from other embankment structures in less seismically active areas.

Hydroelectric Infrastructure and Operation

The primary function of the Yele Dam is hydroelectric power generation. Water from the dam’s reservoir is diverted through a 7.2 kilometres long headrace tunnel before reaching the power station. This tunnel system is integral to the energy production process, channeling water efficiently to the turbines. The project was completed in August 2006, marking the full operational status of the facility. The reservoir began impounding water on January 1, 2005, initiating the gradual filling process that preceded the final commissioning. Construction activities commenced in the year 2000, spanning a six-year period to achieve the final 240 MW capacity. The integration of the dam, reservoir, and headrace tunnel creates a cohesive hydroelectric system that leverages the Nanya River’s flow for sustained energy output.

Geography and Location

The Yele Dam is situated along the Nanya River, a water body that forms the boundary between Mianning County and Shimian County in Sichuan Province, China. This strategic positioning places the infrastructure directly on the administrative border of these two counties, integrating the hydroelectric facility into the regional geography of southwestern China. The dam’s location is defined by its embankment structure spanning the river, creating a reservoir that is critical for the power station's operation.

The site is characterized by significant geological considerations. The dam lies within a Level VIII earthquake intensity zone, a specific seismic classification that directly influenced the engineering design and material selection for the structure. Due to this seismic vulnerability, the core of the dam is composed of asphalt concrete, a choice made to enhance stability and performance under the specific geological stresses of the Nanya River valley. This geological context is a defining feature of the dam’s location, distinguishing it from hydroelectric projects in less seismically active regions.

The Nanya River serves as the primary water source for the Yele Dam project. The river’s flow and the surrounding terrain of Mianning and Shimian Counties provide the necessary hydraulic head and volume to support the 240 MW power station. The location within Sichuan Province places the dam within a broader network of hydroelectric developments in the region, leveraging the natural water resources of the Nanya River for energy production.

Geological and Topographical Context

The geological setting of the Yele Dam is marked by its classification within a Level VIII earthquake intensity zone. This seismic rating necessitated specific construction techniques, including the use of an asphalt concrete core, to ensure the structural integrity of the 124.5 metres high embankment dam. The topography of the border area between Mianning County and Shimian County provides the natural basin for the reservoir, which began impounding on January 1, 2005. The surrounding landscape influences the hydrological behavior of the Nanya River, affecting water flow patterns and sediment transport that are managed by the dam’s infrastructure. The location’s seismic activity is a continuous operational consideration for the maintenance and monitoring of the dam’s performance.

Technical Specifications and Design

The Yele Dam is an embankment structure situated on the Nanya River, spanning the border between Mianning County and Shimian County in Sichuan Province, China. The dam’s design is heavily influenced by its geological setting, specifically its location within a Level VIII earthquake intensity zone. To accommodate this seismic risk, the core of the dam is composed of asphalt concrete, providing necessary flexibility and structural integrity compared to traditional earth-fill or rock-fill cores. This material choice is a critical engineering decision for hydroelectric infrastructure in seismically active regions, ensuring the dam can withstand significant ground movement without catastrophic failure.

The physical dimensions of the dam are substantial, reflecting the topography of the Nanya River valley. The structure stands 124.5 metres (408 ft) high and extends 411 metres (1,348 ft) in length. These measurements define the scale of the reservoir impoundment and the overall footprint of the project. The dam serves as the primary water retention structure for the hydroelectric power station, which has an installed capacity of 240 MW.

Technical Parameters

Parameter Value
Dam Type Embankment dam
Core Material Asphalt concrete
Height 124.5 metres (408 ft)
Length 411 metres (1,348 ft)
Seismic Zone Level VIII earthquake intensity
Installed Capacity 240 MW
Headrace Tunnel Length 7.2 kilometres (4 mi)

The hydroelectric system utilizes a diversion scheme rather than a direct river-run configuration. Water from the reservoir is channeled through a headrace tunnel that is 7.2 kilometres (4 mi) long. This tunnel transports the water from the dam site to the power station, allowing for a significant hydraulic head to drive the turbines. The length of the tunnel is a key factor in determining the efficiency and output of the 240 MW power station. The entire project, including the dam and the power generation infrastructure, was completed in August 2006, following the start of construction in 2000 and the beginning of reservoir impoundment on January 1, 2005.

How does the asphalt concrete core enhance seismic resilience?

The Yele Dam is situated within a Level VIII earthquake intensity zone, a classification that dictates rigorous structural design to withstand significant ground motion. To address these specific seismic risks, the engineering team selected an asphalt concrete core as the primary impermeable barrier for the embankment dam. This material choice is a critical technical decision, as asphalt concrete offers superior ductility and flexibility compared to traditional compacted clay or rolled concrete cores. In a seismic event, the embankment is subject to complex stress patterns, including compression, tension, and shear forces. A rigid core might crack under such dynamic loading, leading to potential leakage or even structural failure. The asphalt concrete core, however, can deform and recover, maintaining its integrity and watertightness even when the surrounding earthfill moves.

Seismic Performance of Asphalt Concrete

The use of asphalt concrete in dam cores is a well-established practice in seismically active regions. The material's viscoelastic properties allow it to absorb energy from earthquake waves, reducing the transmission of stress to the rest of the dam structure. This flexibility helps prevent the formation of continuous cracks that could compromise the dam's ability to hold back the reservoir. For the Yele Dam, which stands 124.5 metres high and 411 metres long, the reliability of the core is paramount. The asphalt concrete core acts as a resilient spine, ensuring that the dam can endure the expected ground accelerations associated with a Level VIII intensity zone without suffering catastrophic failure. This engineering solution directly mitigates the risk of overtopping or foundation shifting, which are common failure modes for embankment dams during strong earthquakes.

Integration with Hydroelectric Operations

The seismic resilience provided by the asphalt concrete core supports the primary function of the Yele Dam: hydroelectric power generation. The dam supports a 240 MW power station, which relies on a consistent water supply from the reservoir. Water is diverted through a 7.2 kilometres long headrace tunnel to reach the turbines. Any significant leakage or structural compromise of the dam could disrupt this flow, leading to reduced power output or temporary shutdowns. By ensuring the dam's structural integrity during seismic events, the asphalt concrete core helps maintain the operational reliability of the power station. This is particularly important for the local grid in Sichuan Province, where the Yele Dam contributes to the regional energy mix. The construction of the dam began in 2000, with the reservoir starting to impound water on January 1, 2005, and the entire project was completed in August 2006. The successful implementation of the asphalt concrete core has been a key factor in the dam's long-term operational stability.

Hydroelectric Power Generation

The Yele Dam supports a hydroelectric power station with an installed capacity of 240 MW. The facility is operational and was completed in August 2006, following the start of reservoir impoundment on January 1, 2005. The primary purpose of the dam infrastructure is to produce hydroelectricity, utilizing the water resources of the Nanya River.

Diversion System and Headrace Tunnel

The power generation process relies on a diversion system that transports water from the dam's reservoir to the turbines. This tunnel serves as the primary conduit, carrying the water from the reservoir to the power station located downstream or at a strategic elevation difference. The design of this diversion system is critical for maintaining the hydraulic head necessary for efficient power generation at the 240 MW capacity rating.

The structural integrity of the dam itself is tailored to the geological conditions of the site. The Yele Dam is an embankment dam, standing 124.5 metres (408 ft) high and 411 metres (1,348 ft) long. Because the dam lies within a Level VIII earthquake intensity zone, its core is composed of asphalt concrete. This specific construction choice enhances the dam's resilience to seismic activity, ensuring the stability of the reservoir and the continuity of water supply to the headrace tunnel and power station.

Operational Flow

The operational flow begins with water stored in the reservoir, which started impounding in 2005. The water is then channeled through the 7.2-kilometre headrace tunnel to reach the power station. Upon reaching the turbines, the hydraulic energy of the water is converted into mechanical energy, which drives generators to produce electricity. The entire project, including the dam, tunnel, and power station, was completed in August 2006, marking the full operational capability of the 240 MW facility. The location of the dam on the border of Mianning County and Shimian County in Sichuan Province provides the necessary topographical gradient for this hydroelectric scheme.

Construction History and Timeline

The construction of the Yele Dam was a significant engineering undertaking located on the Nanya River, straddling the border between Mianning County and Shimian County in Sichuan Province, China. The project was designed to serve as a hydroelectric power station with an installed capacity of 240 MW. The dam is an embankment structure measuring 124.5 metres in height and 411 metres in length. A critical design consideration for the Yele Dam was its location within a Level VIII earthquake intensity zone, which necessitated the use of asphalt concrete for the dam's core to ensure seismic stability.

Construction Phases and Timeline

Construction activities on the Yele Dam commenced in 2000, marking the beginning of the physical development of the infrastructure. The project progressed over several years, leading to the initial impoundment of the reservoir. The reservoir began to hold water on January 1, 2005, which was a key milestone in the operational readiness of the hydroelectric facility. The entire project, including the dam structure and the associated power station, was declared complete in August 2006.

Year Event
2000 Construction on the Yele Dam began.
2005 The reservoir began impounding on January 1.
2006 The entire project was completed in August.

The completion of the Yele Dam in 2006 established it as an operational hydroelectric powerplant in China. The use of asphalt concrete in the core was a specific engineering response to the seismic risks associated with the Level VIII intensity zone in the region. The 7.2-kilometre headrace tunnel is a key component of the power generation system, connecting the reservoir to the 240 MW power station. The dam continues to function as a source of hydroelectricity, utilizing the water flow from the Nanya River. The structural dimensions of 124.5 metres in height and 411 metres in length define the physical scale of the embankment dam. The project timeline from 2000 to 2006 reflects the construction period required to complete the dam, reservoir, and power station infrastructure.

Why it matters

The Yele Dam represents a significant engineering achievement within Sichuan Province's hydroelectric infrastructure, particularly due to its strategic location and specialized design for seismic resilience. Situated on the Nanya River along the border of Mianning County and Shimian County, the facility plays a crucial role in regional power generation. The dam supports a 240 MW power station, contributing to the energy mix of southwestern China. Its operational status, having been fully completed in August 2006, marks it as a mature asset in the region's grid, having begun impounding water on January 1, 2005.

Seismic Engineering and Design

A defining feature of the Yele Dam is its construction response to the high seismic activity of its location. The dam lies within a Level VIII earthquake intensity zone, a critical factor that dictated its structural composition. To withstand significant ground motion, the core of the embankment dam is composed of asphalt concrete. This material choice provides flexibility and durability, essential for maintaining integrity during seismic events. The dam stands 124.5 metres (408 ft) high and spans 411 metres (1,348 ft) in length, dimensions that reflect the scale of the hydroelectric project. Construction began in 2000, indicating a six-year development period to address these complex engineering challenges.

Hydroelectric Infrastructure and Water Diversion

The Yele Dam's hydroelectric system is designed for efficient energy capture through a specific water diversion process. Water from the dam's reservoir is diverted into a 7.2 kilometres (4 mi) long headrace tunnel before reaching the power station. This tunnel system allows for the controlled flow of water, optimizing the hydraulic head for the 240 MW power station. The integration of the dam and the tunnel system exemplifies the technical approach used in Sichuan's mountainous terrain to harness water power. The project's completion in 2006 added a reliable source of renewable energy to the region, leveraging the natural flow of the Nanya River. The dam's role extends beyond mere storage; it is an active component in the conversion of potential energy into electricity, supporting the local grid with its 240 MW capacity. The use of asphalt concrete in the core is a notable engineering decision, highlighting the importance of material science in modern dam construction in seismically active zones. This approach ensures the longevity and safety of the infrastructure, which is vital for continuous power generation in Sichuan Province.

See also