Miranda Dam ( pt, Barragem de Miranda, links=no) is a

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...

buttress dam A buttress dam or hollow dam is a dam with a solid, water-tight upstream side that is supported at intervals on the downstream side by a series of buttresses or supports. The dam wall may be straight or curved. Most buttress dams are made of reinfor ...

on the

Douro The Douro (, , ; es, Duero ; la, Durius) is the highest-flow river of the Iberian Peninsula. It rises near Duruelo de la Sierra in Soria Province, central Spain, meanders south briefly then flows generally west through the north-west part of ...

, where the river forms the national border line between

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

and

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

. It is located in the municipality

Miranda do Douro Miranda do Douro () or Miranda de l Douro in Mirandese () is a city and a municipality in the district of Bragança, northeastern Portugal. The population in 2011 was 7,482, in an area of 487.18 km². The town proper had a population of 1,9 ...

, in

Bragança District Bragança District ( pt, Distrito de Bragança ; mwl, Çtrito de Bergáncia) is a traditional political division of Portugal, in the northeast corner bordering on Spain (Castile and Leon and Galicia), covering 7.4% of the nation's continental l ...

, Portugal. Construction of the dam began in 1955. The dam was completed in 1961. It is owned by ''Companhia Portuguesa de Produção de Electricidade'' (CPPE).

Dam

Miranda Dam is an 80-m-tall (height above foundation) and 263-m-long buttress dam with a crest altitude of 535 m. The volume of the dam is 240,000 m³. The dam contains 4 crest

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure tha ...

s (maximum discharge 11,000 m³/s) and one bottom outlet.

Reservoir

At full reservoir level of 528.05 m (maximum flood level of 533 m) the reservoir of the dam has a surface area of 1.22 km² and its total capacity is 28.1 mio. m³ (active capacity 6.66 mio. m³).

Power plant

The power plant went operational in 1960. It is a

run-of-the-river Run-of-river hydroelectricity (ROR) or run-of-the-river hydroelectricity is a type of hydroelectric generation plant whereby little or no water storage is provided. Run-of-the-river power plants may have no water storage at all or a limited amou ...

hydroelectric Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...

power station. It is owned by CPPE, but operated by EDP. The plant has a

nameplate capacity Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, or maximum effect, is the intended full-load sustained output of a facility such as a power station,

of 369 (390) MW. Its average annual generation is 897.8 (879 or 1,036.3)

GWh A kilowatt-hour (unit symbol: kW⋅h or kW h; commonly written as kWh) is a unit of energy: one kilowatt of power for one hour. In terms of SI derived units with special names, it equals 3.6 megajoules (MJ). Kilowatt-hours are a common bil ...

Miranda I

The power station contains 3

Francis turbine The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency. The proces ...

-generators with 58.84 (67) MW each in an

underground powerhouse An underground power station is a type of hydroelectric power station constructed by excavating the major components (e.g. machine hall, penstocks, and tailrace) from rock, rather than the more common surface-based construction methods. One or mor ...

. The turbine rotation is 150 rpm. The minimum

hydraulic head Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22. It is usually measured as a liquid surface elevation, expressed in units of length, ...

is 51 m, the maximum 66 m. Maximum flow per turbine is 128 m³/s.

Miranda II

In 1995 an additional underground powerhouse was completed and a further Francis turbine with a 193 MW capacity went online. The turbine rotation is 100 rpm. The minimum

is 40 m, the maximum 60 m. Maximum flow of the turbine is 386 m³/s.

References

{{Douro dams Dams in Portugal Hydroelectric power stations in Portugal Buttress dams Dams completed in 1961 Energy infrastructure completed in 1961 1961 establishments in Portugal Buildings and structures in Bragança District Underground power stations Dams on the Douro River

Dam

Reservoir

Power plant

Miranda I

Miranda II

See also

References