The Cachi Dam is located in the province of Cartago, in the canton of Paraíso - Valle de Ujarras, near the town of Cachi, Costa Rica. It is situated on the Reventazon River, one of the country's main rivers.
Lake Cachi is a small artificial lagoon spanning approximately 3.24 km². It is located inland in Costa Rica. The main population center that lends its name to the lake is Cachi, situated 1 kilometer from the eastern shore of the lake.
The reservoir was created by the Cachi Dam, which has a structural configuration of an arch (one of the thinnest in the world), and was constructed by the Costa Rican Institute of Electricity for hydroelectric power generation. It was formed by harnessing the water flows of the Reventazon River.
Furthermore, it is located in one of the most rainfall-rich areas of the country, with an average annual rainfall ranging from 1,200 to 8,000 millimeters. The Cachí Hydroelectric Plant began operation in 1966, with a total installed capacity of 100,800 kW. It stands at an approximate height of 84 meters and has a length of 287 meters at the crest. The reservoir has a storage capacity of around 62 million cubic meters of water.
It is the second water utilization project in the middle basin of the Reventazón River. The powerhouse is located 4 kilometers south of Juan Viñas in the district of Tucurrique, Jiménez canton, while the reservoir and dam are situated in the Cachí district of Paraíso canton, both in the province of Cartago.
Lake Cachi is situated in a narrow alluvial plain with abundant inputs of loosely consolidated sedimentary materials. It is surrounded by low-lying mountains with steep slopes. The reservoir includes the Cachi Dam, located in the northeastern part of the lake, near the town of Ujarrás along National Highway 225 in the middle course of the Reventazon River, in the Ujarras Valley.
The lake was artificially created by the Reventazon River reservoir as it flows in a meandering course to the northeast, through a narrow valley. The river has a total drainage area of 3,000 square kilometers, spanning an altitudinal range from 3,432 meters above sea level at its highest point to its lowest point at its mouth into the Caribbean Sea. The reservoir formed by the Cachi Dam intercepts the upper basin of 919 square kilometers.
The annual precipitation in the entire watershed ranges from 1,200 to 8,000 mm. In 80% of the total surface area of the basin, the terrain varies significantly, with mountains having slopes ranging from 20 to 85 degrees. The average annual water inflow into the reservoir is around 104 cubic meters per second. The gross storage capacity of the reservoir is 51 million cubic meters. The flood discharge capacity of the project is 3,500 cubic meters per second.
The reservoir has a water surface area of 324 hectares (3.24 km²) with a highly irregular shape. It extends for a length of 6 kilometers and has an average width of 1 kilometer, reaching a maximum depth of 69 meters. Approximately 60% of the reservoir basin is covered by forests, while the remaining area consists of agricultural land.
The Cachi Dam is a unique concrete gravity arch dam in the country, with significant historical and touristic value, and incomparable scenic beauty. The structure of the Cachi Dam was designed and constructed by the Swedish company Skanska. Skanska is a global construction and development company with expertise in building infrastructure projects, including hydroelectric dams.
The design of the Cachi Dam is based on the technique of a concrete gravity arch dam, which is a solid and robust structure. This type of dam is constructed using a curved shape that allows the weight of the water stored in the reservoir to be distributed towards the dam's foundation and slopes. This provides stability and strength to the structure. During the construction of the dam, concrete was used to form the dam's structure, and excavation and site preparation works were carried out to ensure a solid foundation.
Furthermore, geotechnical and engineering studies were conducted to assess the feasibility and safety of the project. Skanska undertook the construction of the Cachi Dam between 1961 and 1966, employing modern construction techniques and adhering to the prevailing safety standards and regulations at that time.
It is important to highlight that the construction of large infrastructure projects like a hydroelectric dam involves the participation of multiple companies and specialized professionals from various disciplines, including civil engineers, architects, geologists, among others.
This power plant became part of the National Electric System in the 1960s with an initial capacity of 64,000 kW. It consists of a generation plant with three generating units, each having an installed capacity of 55 megawatts (MW), resulting in a total capacity of 165 MW (two units of 32 MW each). Due to its geographical location, the plant harnesses the water resources from the Macho River (in a cascade system) in addition to the waters of the Reventazón River, Navarro River, and Agua Caliente River. These units were commissioned on May 7, 1966, and January 12, 1967, respectively.
With the Tapantí water conveyance project in 1972 and the expansions that took place in Río Macho between 1976 and 1978, the flow entering the Cachi reservoir was increased, allowing for the installation of a third unit with a capacity of 36,800 kW. This addition completed the plant with a total installed capacity of 100,800 kW, consisting of three units. The third unit began operating on August 4, 1978. The Cachi Dam is one of the main sources of electricity generation in Costa Rica. It contributes significantly to the country's energy supply and is an integral part of the national electric system.
In addition to its power generation function, the Cachi Dam also attracts tourists and visitors due to its scenic beauty. The reservoir created by the dam offers a stunning natural environment, surrounded by mountains and lush vegetation. Activities such as boat rides, fishing, and enjoying panoramic views can be enjoyed in the area.
This iconic hydroelectric project has made a significant impact on the country by providing renewable energy and reducing dependence on fossil fuels, thus protecting the environment. It plays a crucial role in diversifying Costa Rica's energy matrix as the electricity generated by the dam supplies homes, businesses, industries, and public services, ensuring a reliable and continuous power supply. Moreover, it helps enhance resilience against potential fluctuations in energy prices and availability. The project's legacy showcases the country's commitment to sustainable development and the promotion of clean, renewable energy sources.
The Cachi Dam is a notable example of Costa Rica's commitment to renewable energy. Generating electricity from clean sources such as hydroelectric power has contributed to mitigating the greenhouse effect and preserving the environment. By regulating the flow of water, the dam helps control river flooding and ensures a steady water supply in the area, benefiting agriculture and other local uses. In terms of economic development and employment, the construction and operation of the Cachi Dam have created job opportunities and spurred economic growth in the region. This project showcases how sustainable energy initiatives can have positive environmental, social, and economic impacts on a local and national scale.
The hydroelectric infrastructure requires workforce and related services, benefiting the local community in terms of direct and indirect employment, investments, and associated economic activities. The Cachi Hydroelectric Dam plays a crucial role in generating clean and renewable energy, ensuring electrical supply, maintaining grid stability, fostering local economic development, and promoting tourism. Its significance lies in its contribution to sustainable development and the overall well-being of both Costa Rica and the region it is situated in.
Nestled amidst breathtaking landscapes, the Cachi Hydroelectric Dam is much more than a source of energy. It stands as a symbol of innovation, progress, and environmental consciousness. Through its efficient and sustainable operation, it showcases that it is possible to harness natural resources responsibly to meet our energy needs. The Cachi Dam invites us to reflect on the balance between human development and environmental protection, reminding us that we can move towards a cleaner and more prosperous future. It serves as a testament to the possibilities of harmonizing our technological advancements with the preservation of our natural surroundings.
Nestled amidst breathtaking landscapes, the Cachi Hydroelectric Dam is much more than a source of energy. It stands as a symbol of innovation, progress, and environmental consciousness. Through its efficient and sustainable operation, it demonstrates that it is possible to harness natural resources responsibly to meet our energy needs. The Cachi Dam invites us to reflect on the balance between human development and environmental protection, reminding us that we can move towards a cleaner and more prosperous future. It serves as a testament to the possibilities of harmonizing our technological advancements with the preservation of our natural surroundings.