Overview
The Alto Lindoso Dam is a concrete double curvature arch dam situated on the Lima River in Portugal. Located within the municipality of Ponte da Barca in the Viana do Castelo District, the structure lies inside Peneda-Gerês National Park, close to the border with Spain. The dam creates the Alto Lindoso reservoir, also known as the Lindoso reservoir, which serves as a key component of the regional hydroelectric infrastructure. This facility functions as a pumped-storage hydroelectric power station, playing a significant role in the energy mix of the region by leveraging the topography of the Lima River valley.
Technical Specifications and Operations
The dam has a height of 110 m and provides a total installed capacity of 630 MW. It was commissioned in 1992, marking the beginning of its operational life as a major energy asset in northern Portugal. The facility is operated by EDP, a leading energy company in the Iberian Peninsula, which manages the day-to-day operations and maintenance of the hydroelectric infrastructure. The ownership of the pumped-storage station is held by CPPE, which oversees the strategic management of the asset. The concrete double curvature arch design allows the dam to efficiently withstand the hydrostatic pressure of the reservoir, making it a robust engineering solution for the rugged terrain of the Peneda-Gerês National Park.
Geographical and Environmental Context
Alto Lindoso Dam is strategically positioned within Peneda-Gerês National Park, one of the oldest national parks in Europe. Its location in the Viana do Castelo District places it in a region characterized by significant rainfall and rugged topography, which are ideal conditions for hydroelectric power generation. The proximity to the Spanish border highlights the transnational nature of the Lima River basin, although the dam itself is a Portuguese infrastructure project. The creation of the Alto Lindoso reservoir has had notable environmental impacts, influencing the local ecosystem and water management strategies in the area. The dam's operation contributes to the stability of the regional power grid, providing flexible energy storage and generation capabilities that are essential for balancing supply and demand in the Portuguese energy market. The facility remains operational, continuing to serve as a vital energy resource for the country.
Why it matters
The Alto Lindoso Dam holds significant geopolitical and social importance due to its unique cross-border configuration. The reservoir created by the dam extends beyond the immediate boundaries of the Peneda-Gerês National Park, spilling over into neighboring Spain. This geographical feature is not merely incidental but is the result of a specific historical arrangement between Portugal and Spain. The expansion of the water body into Spanish territory was facilitated by a compulsory acquisition of land by a Portuguese company, a process rooted in a diplomatic deal between the regimes of Francisco Franco and António de Oliveira Salazar. This agreement allowed for the strategic use of transboundary land to maximize the storage capacity of the Alto Lindoso reservoir, integrating Spanish terrain into the Portuguese energy infrastructure.
Social Impact and Drowned Villages
The creation of the Alto Lindoso reservoir required the submersion of five villages, fundamentally altering the social and demographic landscape of the region. These communities were sacrificed to secure the water storage necessary for the pumped-storage operation, leading to the displacement of local populations and the loss of historic settlements. The social cost of the dam is evident in the five drowned villages that lie beneath the water levels, serving as a testament to the trade-offs involved in large-scale hydroelectric development in the Peneda-Gerês area. The compulsory acquisition process, driven by the Franco-Salazar agreement, directly impacted the residents of these villages, whose lands were taken to support the energy needs of the broader region.
Recent Emergence of Aceredo
In recent years, the dynamic nature of the Alto Lindoso reservoir has brought renewed attention to the submerged areas. In 2022, the village of Aceredo emerged from the waters due to a significant drought. This event provided a rare visual and physical reconnection with the historical landscape that was lost during the dam's construction. The emergence of Aceredo highlights the vulnerability of the reservoir's water levels to climatic variations and offers a tangible reminder of the communities that were drowned to create the 630 MW pumped-storage facility. The visibility of Aceredo serves as a poignant illustration of the intersection between energy infrastructure, historical agreements, and environmental change in the Viana do Castelo District.
What is the engineering design of Alto Lindoso Dam?
This structural design is characteristic of the region's hydroelectric infrastructure, leveraging the valley's topography to support the reservoir created by the dam, known as the Alto Lindoso or Lindoso reservoir.
Dam Dimensions
The dam's engineering specifications define its capacity to hold back the Lima River. The structure stands at a height of 110 m and has a length of 297 m. The total volume of concrete used in the construction is 308,500 m3. The crest altitude is 339 m. The following table summarizes the key dimensional data:
| Parameter | Value |
|---|---|
| Type | Concrete double curvature arch dam |
| Height | 110 m |
| Length | 297 m |
| Volume | 308,500 m3 |
| Crest Altitude | 339 m |
Spillways and Bottom Outlets
The dam features a system of spillways designed to manage water flow and discharge. There are two shaft spillways, each equipped with three gates. The total discharge capacity of these spillways is 2,760 m3/s. Additionally, the dam includes two bottom outlets to facilitate drainage and flow control. The combined discharge capacity of the bottom outlets is 400 m3/s. These components are integral to the operational management of the Alto Lindoso reservoir and the associated pumped storage facility operated by EDP.
How does the pumped-storage system work?
The Alto Lindoso pumped-storage facility operates as a critical component of Portugal's hydroelectric infrastructure, utilizing the elevation difference between upper and lower reservoirs to store and generate energy. The system is anchored by the concrete double curvature arch dam on the Lima River, located in the Peneda-Gerês National Park. This configuration allows for flexible power generation, essential for balancing the national grid.
Power Plant Configuration
The power generation capability is housed in an underground powerhouse, situated at a depth of 340 m below the surface. This subterranean location minimizes the visual impact on the surrounding landscape while providing structural stability. The plant is equipped with two Francis turbine-generators, each rated at 317 MW, contributing to the total installed capacity of 630 MW. These turbines operate at a rotation speed of 214.3 rpm, optimized for the specific hydraulic conditions of the site.
The hydraulic head for the system ranges between 227 m and 288 m, depending on the water levels in the reservoirs. The design flow rate is 125 m3/s, allowing for efficient energy conversion during peak demand periods. The water flows from the upper reservoir, through the penstocks, and drives the turbines before being discharged into the tailrace.
Hydraulic Connections
The pumped-storage cycle relies on the connection between the Alto Lindoso reservoir and the lower reservoir at Touvedo Dam. Water is conveyed from the powerhouse to the lower reservoir via a 4,883 m long tailrace tunnel. This tunnel system ensures efficient water discharge and minimizes energy loss during the generation phase. During pumping operations, water is lifted from the Touvedo reservoir back to the Alto Lindoso reservoir, storing potential energy for future use.
| Parameter | Value |
|---|---|
| Installed Capacity | 630 MW |
| Turbine Type | Francis |
| Number of Turbines | 2 |
| Capacity per Turbine | 317 MW |
| Rotation Speed | 214.3 rpm |
| Hydraulic Head | 227–288 m |
| Flow Rate | 125 m3/s |
| Powerhouse Depth | 340 m |
| Tailrace Tunnel Length | 4,883 m |
Reservoir characteristics and hydrology
The Alto Lindoso reservoir is the primary water storage body for the pumped storage scheme, formed by the concrete double curvature arch dam on the Lima River. The reservoir is situated within the Peneda-Gerês National Park, close to the border with Spain, and is also known as the Lindoso reservoir. The total capacity of the reservoir is 379.01 million m3, with an active capacity of 270 hm3. The surface area of the reservoir is 10.72 km2.
Operating levels and hydrology
The operating levels of the Alto Lindoso reservoir are defined by a full level of 338 m and a minimum level of 280 m. These levels determine the active storage volume available for electricity production. The electricity production potential of the reservoir is 224.6 GWh from 347.9 million m3 of water. This production potential is derived from the hydraulic head and the volume of water available for release through the turbines of the EDP-operated facility.
2022 drought event
During the 2022 drought event, the water levels in the Alto Lindoso reservoir dropped significantly, causing the village of Aceredo to re-emerge. The village had been submerged by the reservoir since the commissioning of the dam in 1992. The re-emergence of Aceredo provided a visible indicator of the severity of the drought in the Viana do Castelo District and the broader region. The event highlighted the vulnerability of the reservoir's storage capacity to climatic variations and the impact on local geography and infrastructure.
History of construction and social impact
Construction of the Alto Lindoso Dam commenced in 1983, initiating a significant infrastructure project within the Peneda-Gerês National Park. The site, located in the municipality of Ponte da Barca in the Viana do Castelo District, was chosen for its strategic position on the Lima River, close to the border with Spain. The engineering design featured a concrete double curvature arch dam, intended to create the Alto Lindoso reservoir, also known as the Lindoso reservoir. This project was a key component of the energy infrastructure development in northern Portugal, managed by the operator EDP.
Compulsory acquisition and social disruption
The expansion of the reservoir required the compulsory acquisition of several Spanish villages, leading to substantial social impact across the border. In 1991, EDP executed the acquisition of the villages of Aceredo, Buscalque, O Bao, A Reloeira, and Lantemil. This decision affected the local population significantly, necessitating the relocation of 120 citizens from the village of Aceredo alone. The process involved the physical moving of community landmarks, including a church and a cemetery, to accommodate the rising water levels of the newly formed reservoir.
Protests and community response
The forced relocation sparked considerable unrest among the affected residents. Protests emerged as the primary form of resistance, with community members organizing demonstrations to voice their dissatisfaction with the acquisition terms and the disruption to their ancestral lands. Hunger strikes were also employed as a tactic to draw attention to the plight of the displaced families. These actions highlighted the tension between national energy infrastructure goals and the socio-cultural heritage of the border communities. The protests underscored the human cost of the dam's construction, bringing international attention to the specific case of the Spanish villages absorbed by the Portuguese reservoir.
Completion and operational status
Despite the social controversies and construction challenges, the Alto Lindoso Dam was completed in 1992. The facility became operational, contributing 630 MW of pumped storage capacity to the regional grid. The dam remains a functional part of Portugal's energy infrastructure, managed by EDP. The completion marked the end of the initial construction phase, although the social impact on the relocated communities from Aceredo and surrounding areas continued to be a point of reference in the history of the Lima River basin development. The reservoir stands as a testament to the engineering efforts of the early 1990s, situated within the natural landscape of the Peneda-Gerês National Park.